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  • 1. Acharya, Kamal Prasad
    et al.
    De Frenne, Pieter
    Brunet, Jörg
    Chabrerie, Olivier
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Diekmann, Martin
    Hermy, Martin
    Kolb, Annette
    Lemke, Isgard
    Plue, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Verheyen, Kris
    Graae, Bente Jessen
    Latitudinal variation of life-history traits of an exotic and a native impatiens species in Europe2017In: Acta Oecologica, ISSN 1146-609X, E-ISSN 1873-6238, Vol. 81, p. 40-47Article in journal (Refereed)
    Abstract [en]

    Understanding the responses of invasive and native populations to environmental change is crucial for reliable predictions of invasions in the face of global change. While comparisons of responses across invasive species with different life histories have been performed before, comparing functional traits of congeneric native and invasive species may help to reveal driving factors associated with invasion. Here we compared morphological functional trait patterns of an invasive species (Impatiens parviflora) with its congeneric native species (I. noli-tangere) along an approximately 1600 km European latitudinal gradient from France (49 degrees 34'N) to Norway (63 degrees 40'N). Soil nitrogen was recorded during six weeks of the growing season, and light, soil moisture, and nutrient availability were estimated for each sampled population using community weighted means of indicator values for co-occurring species. Temperature data were gathered from nearby weather stations. Both the native and invasive species are taller at higher latitudes and this response is strongest in the invasive species. Seed mass and number of seeds per capsule increase in I. noli-tangere but decrease in I. parviflora towards higher latitudes. Surprisingly, plant height in the invasive I. parviflora decreases with increasing soil nitrogen availability. The latitudinal pattern in seed mass is positively related to temperature in I. noli-tangere and negatively in I. parviflora. Leaf area of both species decreases with increasing Ellenberg indicator values for nitrogen and light but increases with increasing soil moisture. Soil nitrogen concentrations and Ellenberg indicator values for nitrogen have significant positive (I. nolitangere) and negative (I. parviflora) effects on the number of seeds per capsule. Our results show that the native I. noli-tangere has efficient reproduction at its range edge while the invasive I. parviflora shows a marked decrease in seed size and seed number per capsule. These patterns are unrelated to the growth and obtained size of the plants: even low soil nitrogen availability in the north seemed not to limit plant growth and size. Our results suggest that the invasive I. parviflora tends to become more invasive at lower latitudes by producing heavier seeds and more seeds per capsule.

  • 2.
    Aggemyr, Elsa
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Auffret, Alistair G.
    Stockholm University, Faculty of Science, Department of Physical Geography. Swedish University of Agricultural Sciences, Sweden.
    Jädergård, Love
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Species richness and composition differ in response to landscape and biogeography2018In: Landscape Ecology, ISSN 0921-2973, E-ISSN 1572-9761, Vol. 33, no 12, p. 2273-2284Article in journal (Refereed)
    Abstract [en]

    Context Understanding how landscape patterns affect species diversity is of great importance in the fields of biogeography, landscape ecology and conservation planning, but despite the rapid advance in biodiversity analysis, investigations of spatial effects on biodiversity are still largely focused on species richness.

    Objectives We wanted to know if and how species richness and species composition are differentially driven by the spatial measures dominating studies in landscape ecology and biogeography. As both measures require the same limited presence/absence information, it is important to choose an appropriate diversity measure, as differing results could have important consequences for interpreting ecological processes.

    Methods We recorded plant occurrences on 112 islands in the Baltic archipelago. Species richness and composition were calculated for each island, and the explanatory power of island area and habitat heterogeneity, distance to mainland and structural connectivity at three different landscape sizes were examined.

    Results A total of 354 different plant species were recorded. The influence of landscape variables differed depending on which diversity measure was used. Island area and structural connectivity determined plant species richness, while species composition revealed a more complex pattern, being influenced by island area, habitat heterogeneity and structural connectivity.

    Conclusions Although both measures require the same basic input data, species composition can reveal more about the ecological processes affecting plant communities in fragmented landscapes than species richness alone. Therefore, we recommend that species community composition should be used as an additional standard measure of diversity for biogeography, landscape ecology and conservation planning.

  • 3.
    Aggemyr, Elsa
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Landscape structure and land use history influence changes in island plant composition after 100 years2012In: Journal of Biogeography, ISSN 0305-0270, E-ISSN 1365-2699, Vol. 39, no 9, p. 1645-1656Article in journal (Refereed)
    Abstract [en]

    Aim We investigated how current and historical land use and landscape structure affect species richness and the processes of extinction, immigration and species turnover. Location The northern part of the Stockholm archipelago, Baltic Sea, Sweden. We resurveyed 27 islands ranging from 0.3 to 33 ha in area. Methods We compared current plant survey data, cadastral maps and aerial photographs with records obtained from a survey in 1908, using databases and a digital elevation model to examine changes in plant community dynamics in space and time. We examined the effects of local and landscape structure and land use changes on plant species dynamics by using stepwise regression in relation to eight local and three landscape variables. The eight local variables were area, relative age, shape, soil heterogeneity, bedrock ratio, number of houses, forest cover change, and grazing 100 years ago. The three landscape variables were distance to mainland, distance to closest island with a farm 100 years ago, and structural connectivity. Hanskis connectivity measure was modified to incorporate both connectivity and fragmentation. Results The investigated islands have undergone drastic changes, with increasing forest cover, habitation, and abandonment of grassland management. Although the total species richness increased by 31% and mean island area by 23%, we found no significant increase in species richness per unit area. Local variables explain past species richness (100 years ago), whereas both local and landscape variables explain current species richness, extinctions, immigrations and species turnover. Grazing that occurred 100 years ago still influences species richness, even though grazing management was abandoned several decades ago. The evidence clearly shows an increase in nitrophilous plant species, particularly among immigrant species. Main conclusions This study highlights the importance of including land use history when interpreting current patterns of species richness. Furthermore, local environment and landscape patterns affect important ecological processes such as immigration, extinction and species turnover, and hence should be included when assessing the impact of habitat fragmentation and land use change. We suggest that our modified structural connectivity measure can be applied to other types of landscapes to investigate the effects of fragmentation and habitat loss.

  • 4.
    Aggemyr, Elsa
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology (INK).
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology (INK).
    Revisiting 27 islands in the Stockholm archipelago after a century – the effect of land use change on species composition2010Conference paper (Refereed)
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  • 5. Albert, Aurélie
    et al.
    Auffret, Alistair G.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Cosyns, Eric
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    D'hondt, Bram
    Eichberg, Carsten
    Eycott, Amy E.
    Heinken, Thilo
    Hoffmann, Maurice
    Jaroszewicz, Bogdan
    Malo, Juan E.
    Mårell, Anders
    Mouissie, Maarten
    Pakeman, Robin J.
    Picard, Mélanie
    Plue, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Poschlod, Peter
    Provoost, Sam
    Schulze, Kiowa Alraune
    Baltzinger, Christophe
    Seed dispersal by ungulates as an ecological filter: a trait-based meta-analysis2015In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 124, no 9, p. 1109-1120Article in journal (Refereed)
    Abstract [en]

    Plant communities are often dispersal-limited and zoochory can be an efficient mechanism for plants to colonize new patches of potentially suitable habitat. We predicted that seed dispersal by ungulates acts as an ecological filter - which differentially affects individuals according to their characteristics and shapes species assemblages - and that the filter varies according to the dispersal mechanism (endozoochory, fur-epizoochory and hoof-epizoochory). We conducted two-step individual participant data meta-analyses of 52 studies on plant dispersal by ungulates in fragmented landscapes, comparing eight plant traits and two habitat indicators between dispersed and non-dispersed plants. We found that ungulates dispersed at least 44% of the available plant species. Moreover, some plant traits and habitat indicators increased the likelihood for plant of being dispersed. Persistent or nitrophilous plant species from open habitats or bearing dry or elongated diaspores were more likely to be dispersed by ungulates, whatever the dispersal mechanism. In addition, endozoochory was more likely for diaspores bearing elongated appendages whereas epizoochory was more likely for diaspores released relatively high in vegetation. Hoof-epizoochory was more likely for light diaspores without hooked appendages. Fur-epizoochory was more likely for diaspores with appendages, particularly elongated or hooked ones. We thus observed a gradient of filtering effect among the three dispersal mechanisms. Endozoochory had an effect of rather weak intensity (impacting six plant characteristics with variations between ungulate-dispersed and non-dispersed plant species mostly below 25%), whereas hoof-epizoochory had a stronger effect (eight characteristics included five ones with above 75% variation), and fur-epizoochory an even stronger one (nine characteristics included six ones with above 75% variation). Our results demonstrate that seed dispersal by ungulates is an ecological filter whose intensity varies according to the dispersal mechanism considered. Ungulates can thus play a key role in plant community dynamics and have implications for plant spatial distribution patterns at multiple scales.

  • 6.
    Arnell, Matilda
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Does historical land use affect the regional distribution of fleshy-fruited woody plants?2019In: PLOS ONE, E-ISSN 1932-6203, Vol. 14, no 12, article id e0225791Article in journal (Refereed)
    Abstract [en]

    Species richness and composition of current vegetation may reflect historical land use. We develop and examine the hypothesis that regional distribution and richness of fleshy-fruited woody plants, a group sharing life-form and dispersal system, reflect historical land use in open or semi-open habitats. Historical land use was based on maps from around the year 1900 for two regions in Sweden, and field data was gathered from surveys made in these regions. Species richness was positively related to historical land use indicated as open habitat in 1900. In one of the regions, five out of nine examined species were positively related to historical land use (with historical effect R-2 ranging between 0.03 and 0.22). In the other region, we found a weaker positive relationship with historical land use in two out of nine examined species (R-2 0.01 and 0.02). We conclude that current occurrence and richness of fleshy-fruited woody species is partly a legacy of historical land use, and that regions may vary in this respect. Based on a comparison between the two regions examined here, we discuss some potential causes behind this variation.

  • 7.
    Auffret, Alistair G.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Aggemyr, Elsa
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Plue, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Spatial scale and specialization affect how biogeography and functional traits predict long-term patterns of community turnover2017In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 31, no 2, p. 436-443Article in journal (Refereed)
    Abstract [en]

    1. Immigration, extirpation and persistence of individual populations of species are key processes determining community responses to environmental change. However, they are difficult to study over long time periods without corresponding historical and modern-day species occurrences.

    2. We used historical and present-day plant species occurrence data from two different spatial scales (resolutions) to investigate the plant community turnover during the 20th century in a Baltic Sea archipelago. Patterns of turnover were analysed in relation to plant functional traits relating to dispersal and competition/persistence, as well as biogeographical variables.

    3. Turnover was largely driven by interactions between functional traits and measures of area, connectivity and distance to mainland. However, the combinations of traits and biogeographical variables that were most important for predicting immigration and extirpation differed between data sets, and between species associated with grassland management and the entire species pool.

    4. Taller plants were more likely to persist regardless of scale and biogeography, reflecting the grazing abandonment that occurred in the study area. Interactions between dispersal traits and biogeography were related to immigrations when the entire species pool was considered. However, increased dispersal potential, a smaller island size and increasing distance to mainland combined to promote extirpations in management-associated species. A perennial life span and seed banking contributed to species persistence. At the larger spatial scale, trait-driven turnover was not mediated by the biogeographical context.

    5. We showed that it is important to consider functional traits, biogeographical variables and their interactions when analysing community turnover over time. Furthermore, we found that the understanding of how combinations of traits and biogeography predict turnover depends on the source and spatial scale of the available data, and the species pool analysed.

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  • 8.
    Auffret, Alistair G.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Berg, Johan
    Stockholm University, Faculty of Social Sciences, Department of Human Geography.
    Cousins, Sara
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Dispersal geography: a new concept for managing seed dispersal in rural landscapesManuscript (preprint) (Other academic)
  • 9.
    Auffret, Alistair G.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Humans as Long-Distance Dispersers of Rural Plant Communities2013In: PLOS ONE, E-ISSN 1932-6203, Vol. 8, no 5, article id e62763Article in journal (Refereed)
    Abstract [en]

    Humans are known for their capacity to disperse organisms long distances. Long-distance dispersal can be important for species threatened by habitat destruction, but research into human-mediated dispersal is often focused upon few and/or invasive species. Here we use citizen science to identify the capacity for humans to disperse seeds on their clothes and footwear from a known species pool in a valuable habitat, allowing for an assessment of the fraction and types of species dispersed by humans in an alternative context. We collected material from volunteers cutting 48 species-rich meadows throughout Sweden. We counted 24 354 seeds of 197 species, representing 34% of the available species pool, including several rare and protected species. However, 71 species (36%) are considered invasive elsewhere in the world. Trait analysis showed that seeds with hooks or other appendages were more likely to be dispersed by humans, as well as those with a persistent seed bank. More activity in a meadow resulted in more dispersal, both in terms of species and representation of the source communities. Average potential dispersal distances were measured at 13 km. We consider humans capable seed dispersers, transporting a significant proportion of the plant communities in which they are active, just like more traditional vectors such as livestock. When rural populations were larger, people might have been regular and effective seed dispersers, and the net rural-urban migration resulting in a reduction in humans in the landscape may have exacerbated the dispersal failure evident in declining plant populations today. With the fragmentation of habitat and changes in land use resulting from agricultural change, and the increased mobility of humans worldwide, the dispersal role of humans may have shifted from providers of regular local and landscape dispersal to providers of much rarer long-distance and regional dispersal, and international invasion.

  • 10.
    Auffret, Alistair G.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography. Swedish University of Agricultural Sciences, Sweden; University of York, UK.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Land uplift creates important meadow habitat and a potential original niche for grassland species2018In: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 285, no 1876, article id 20172349Article in journal (Refereed)
    Abstract [en]

    Semi-natural grasslands have been severely affected by agricultural land-use change. However, the isostatic land adjustment following deglaciation in the Northern Hemisphere means that new land is continually being created in coastal areas. We modelled isostatic adjustment during the last 4000 years in a region of the Baltic coast to estimate the emergence of potential grassland habitat. We also compared the alpha and beta diversity of existing managed and abandoned coastal meadows, and assessed their contribution to biodiversity at landscape scales. We estimated that half the 7866 km(2) of emerging land had the potential to become coastal meadow habitat, which is an order of magnitude larger than the total area of all valuable semi-natural grassland in the study region today. The small area of managed coastal habitat remaining was found to have a disproportionate influence on the richness of threatened species at landscape scales, but our results also show that continued management is essential for the maintenance of grassland biodiversity. Our combination of approaches identifies uplifted coastal meadows as an additional original niche for grassland plant species, while highlighting that low-intensity disturbance through grassland management is essential for the maintenance of diversity at multiple scales.

  • 11.
    Auffret, Alistair G.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Past and present management influences the seed bank and seed rain in a rural landscape mosaic2011In: Journal of Applied Ecology, ISSN 0021-8901, E-ISSN 1365-2664, Vol. 48, no 5, p. 1278-1285Article in journal (Refereed)
    Abstract [en]

    1. Seed bank and seed rain represent dispersal in time and space. They can be important sources of diversity in the rural landscape, where fragmented habitats are linked by their histories. 2. Seed bank, seed rain and above-ground vegetation were sampled in four habitat types (abandoned semi-natural grassland (ABA), grazed former arable field (FAF), mid-field islet (MFI) and grazed semi-natural grassland (SNG)) in a rural landscape in southern Sweden, to examine whether community patterns can be distinguished at large spatial scales and whether seed bank and seed rain are best explained by current, past or intended future vegetation communities. 3. We counted 54 357 seedlings of 188 species from 1190 seed bank and 797 seed rain samples. Seed bank, seed rain and above-ground vegetation communities differed according to habitat. Several species characteristic of managed grassland vegetation were present in the seed bank, seed rain and vegetation of the other habitats. 4. The seed banks of SNGs and the seed rain of the FAFs were generally better predicted by the surrounding above-ground vegetation than were the other habitat types. The seed rain of the grazed communities was most similar to the vegetation in the FAFs, while the seed banks of the abandoned grasslands most resembled the vegetation in SNGs. 5. Gap availability and seed input could be limiting the colonisation of target species in FAFs, while remnant populations in the seed bank and the presence of grassland specialists in the above-ground vegetation indicate that abandoned grasslands and mid-field islets could be valuable sources of future diversity in the landscape after restoration. 6. Synthesis and applications. SNG communities are able to form seed banks which survive land-use change, but their seed rain does not reflect their above-ground communities. It is important that grassland plants set seed. By connecting existing grasslands with restoration targets, increased disturbance in the target habitats would allow for colonisation via the seed bank or seed rain, while decreased grazing intensity would benefit seed production in the source grasslands. Otherwise, landscape-wide propagule availability might increase with a more varied timing and intensity of management.

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  • 12.
    Auffret, Alistair G.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Cousins, Sara A.O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Grassland connectivity by motor vehicles and grazing livestock2013In: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 36, no 10, p. 1150-1157Article in journal (Refereed)
    Abstract [en]

    In addition to habitat loss and fragmentation, agricultural change has led to a change in seed dispersal processes in therural landscape through a loss of structural and functional connectivity. Here, human-mediated dispersal vectors areprevalent, and we explored whether the loss of connectivity via free-ranging livestock could be mitigated by the increasein roads and motor vehicles. We found that structurally, 39% of all valuable semi-natural grassland habitats in southernSweden are adjacent to public road verges, which in the rural landscape are often considered to be suitable habitat forgrassland species. Additionally, by collecting mud attached to cars and farming machinery and manure from livestock(cattle, horse, sheep) grazing semi-natural grassland pasture, we found that motor vehicles are also capable seed dispers-ers. A similar number of species were dispersed by both vectors, although the composition of samples was quite different.Motor vehicles dispersed more grassland specialists than invasive species, although in much lower abundances than didgrazing livestock. Despite these differences, motor vehicles were found to be able to disperse species with the same kindsof dispersal traits as livestock. A high number of seeds, species and specialists in manure samples means that greater move-ment of livestock is desirable to increase functional grassland connectivity. However, effective management could improvethe suitability of roadsides as grassland corridors and increase the availability of seeds for long-distance human-mediateddispersal via cars and tractors. Our results suggest that in many rural landscapes, connectivity by road networks couldhelp mediate habitat loss and fragmentation of grasslands. However, such effects can be context dependent, and the con-nectivity provided by roads could have serious negative consequences in other regions.

  • 13.
    Auffret, Alistair G.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography. University of York, UK.
    Kimberley, Adam
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Plue, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Skånes, Helle
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Jakobsson, Simon
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Waldén, Emelie
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Wennbom, Marika
    Wood, Heather
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Bullock, James M.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Gartz, Mira
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Hooftman, Danny A. P.
    Tränk, Louise
    Stockholm University, Faculty of Science, Department of Physical Geography.
    HistMapR: Rapid digitization of historical land-use maps in R2017In: Methods in Ecology and Evolution, E-ISSN 2041-210X, Vol. 8, no 11, p. 1453-1457Article in journal (Refereed)
    Abstract [en]

    Habitat destruction and degradation represent serious threats to biodiversity, and quantification of land-use change over time is important for understanding the consequences of these changes to organisms and ecosystem service provision. Comparing land use between maps from different time periods allows estimation of the magnitude of habitat change in an area. However, digitizing historical maps manually is time-consuming and analyses of change are usually carried out at small spatial extents or at low resolutions. HistMapR contains a number of functions that can be used to semi-automatically digitize historical land use according to a map's colours, as defined by the RGB bands of the raster image. We test the method on different historical land-use map series and compare results to manual digitizations. Digitization is fast, and agreement with manually digitized maps of around 80-90% meets common targets for image classification. We hope that the ability to quickly classify large areas of historical land use will promote the inclusion of land-use change into analyses of biodiversity, species distributions and ecosystem services.

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  • 14.
    Auffret, Alistair G.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Plue, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    The spatial and temporal components of functional connectivity in fragmented landscapes2015In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, p. s51-S59Article in journal (Refereed)
    Abstract [en]

    Connectivity is key for understanding how ecological systems respond to the challenges of land-use change and habitat fragmentation. Structural and functional connectivity are both established concepts in ecology, but the temporal component of connectivity deserves more attention. Whereas functional connectivity is often associated with spatial patterns (spatial functional connectivity), temporal functional connectivity relates to the persistence of organisms in time, in the same place. Both temporal and spatial processes determine biodiversity responses to changes in landscape structure, and it is therefore necessary that all aspects of connectivity are considered together. In this perspective, we use a case study to outline why we believe that both the spatial and temporal components of functional connectivity are important for understanding biodiversity patterns in the present-day landscape, and how they can also help us to make better-informed decisions about conserving and restoring landscapes and improving resilience to future change.

  • 15.
    Auffret, Alistair G.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography. University of York, UK.
    Rico, Yessica
    Bullock, James M.
    Hooftman, Danny A. P.
    Pakeman, Robin J.
    Soons, Merel B.
    Suarez-Esteban, Alberto
    Traveset, Anna
    Wagner, Helene H.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Plant functional connectivity - integrating landscape structure and effective dispersal2017In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 105, no 6, p. 1648-1656Article, review/survey (Refereed)
    Abstract [en]

    1. Dispersal is essential for species to survive the threats of habitat destruction and climate change. Combining descriptions of dispersal ability with those of landscape structure, the concept of functional connectivity has been popular for understanding and predicting species' spatial responses to environmental change. 2. Following recent advances, the functional connectivity concept is now able to move beyond landscape structure to consider more explicitly how other external factors such as climate and resources affect species movement. We argue that these factors, in addition to a consideration of the complete dispersal process, are critical for an accurate understanding of functional connectivity for plant species in response to environmental change. 3. We use recent advances in dispersal, landscape and molecular ecology to describe how a range of external factors can influence effective dispersal in plant species, and how the resulting functional connectivity can be assessed. 4. Synthesis. We define plant functional connectivity as the effective dispersal of propagules or pollen among habitat patches in a landscape. Plant functional connectivity is determined by a combination of landscape structure, interactions between plant, environment and dispersal vectors, and the successful establishment of individuals. We hope that this consolidation of recent research will help focus future connectivity research and conservation.

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  • 16.
    Auffret, Alistair G.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Schmucki, Reto
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Reimark, Josefin
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Grazing networks provide useful functional connectivity for plants in fragmented systems2012In: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 23, no 5, p. 970-977Article in journal (Refereed)
    Abstract [en]

    Question To what extent does the movement of animals between fragmented habitat patches provide functional connectivity via endozoochorous seed dispersal? Location The Stockholm archipelago, Sweden. Methods We followed all movements of livestock between islands during one grazing season. After each movement, manure was collected and its seed content assessed through seedling emergence. Seedling data were then compared to vegetation surveys from the grazed islands with regard to functional traits. Results Light- and nitrogen-demanding locally abundant species, and those with relatively small and persistent seeds were more likely to be moved between islands. For quantitative traits, only a subset of the available trait ranges were dispersed, with extreme values left behind. Species apparently specialized to other means of dispersal emerged from the manure samples. Neither dispersed traits nor seed density changed with timing of movement, but seed richness and diversity both increased throughout the season. The subsets of endozoochorously-dispersed species in the established vegetation were more similar than non-dispersed subsets between islands linked by livestock. Conclusions Grazing networks contribute to the connectivity of the core species in the system, and could provide useful tools for grassland management in fragmented landscapes.

  • 17.
    Auffret, Alistair
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Schmucki, Reto
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Reimark, Josefin
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Cousins, Sara
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    A trait-based analysis of the functional connectivity provided by mobile grazers in an island grazing system2011In: 8th IALE World Congress, Beijing 18-21 August 2011: Landscape Ecology for Sustainable Environment and Culture, 2011Conference paper (Refereed)
    Abstract [en]

    The area of species-rich semi-natural grassland in Europe has declined dramatically duringthe past two centuries. The Stockholm archipelago was once a vibrant agricultural landscape,with the movement of livestock between islands forming an extensive grazing network. Likein much of Europe, agricultural industrialisation led to most grasslands either beingabandoned to become scrub or woodland, or converted to arable fields and subsequentlyreverted to relatively species-poor pasture. The restoration of these habitats to species-richgrassland communities has been a major goal, but restoration success has often been found tobe seed or dispersal limited. In island systems, the hostility of the matrix exacerbates thisproblem, but also provides an ideal study system for investigating the dispersal of plantspecies between fragmented habitats. One management strategy has been to restart smallgrazing networks to improve connectivity in the landscape, and in the summer of 2009, wecollected fresh manure samples from grazing cattle and sheep after movement by boatbetween islands. These were then grown in a greenhouse, and 5915 seedlings of 74 speciesemerged from the 18 samples, corresponding to 18 movements within the grazing network.Comparing the species dispersed with the vegetation communities in the donor and receiverislands, we assess the subset of species and species traits which were transported. We can thusexamine the extent of the functional connectivity provided by these mobile grazers, and theeffect that timing of movement has on the range of species and traits dispersed.

  • 18.
    Borgström, Sara
    et al.
    Stockholm University, Faculty of Science, Department of Systems Ecology.
    Cousins, Sara
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Outside the boundary - land use changes in the surroundings of urban nature reserves2012In: Applied Geography, ISSN 0143-6228, E-ISSN 1873-7730, Vol. 32, no 2, p. 350-359Article in journal (Refereed)
    Abstract [en]

    The importance of the landscape surrounding a protected area for sustaining its values is frequently discussed in conservation literature. Studies on the interactions of urbanisation and nature conservation at the global scale suggest that protected nature attracts urbanisation, and that this in turn might negatively impact the area. However, studies specifically addressing such land use dynamics at city scale are largely missing. In this study we examine the change in proportion of built up area in two zones (500 m and 1000 m) surrounding 15 urban nature reserves in southern Sweden. By using comprehensive maps from the last 50 years, we compared the zones to the overall urbanisation in the cities to reveal discrepancies in land use surrounding the nature reserves. We found that the amount of built up area in the buffer zones surrounding nature reserves followed the same trend as the corresponding cities and this relation was stable over time, although the positive relationship was not significant. The establishment of nature reserves had no detectable effect on surrounding land use, however two distinguished groups of reserves were identified with either more or less built up area in buffers zones compared to cities. These differences were related to specific local drivers such as land ownership, land use history and nature reserve location. In contrast to earlier studies at global scale, our study did not show that nature reserves attract urbanisation. Instead, we stress that the great variety of contextual factors at the city scale makes quantitative analysis of this kind extremely difficult. However, a general neglect from planning and nature conservation agencies to recognise nature reserves’ dependence on the surrounding landscape configuration could be detrimental to sustain their values in the long-term. Hence we suggest that zones surrounding nature-protected areas should be planned and managed according to local land use history and current landscape conditions to enable and enhance necessary cross-boundary interactions.

  • 19. Brunet, Jörg
    et al.
    Hedwall, Per-Ola
    Lindgren, Jessica
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Immigration credit of temperate forest herbs in fragmented landscapes—Implications for restoration of habitat connectivity2021In: Journal of Applied Ecology, ISSN 0021-8901, E-ISSN 1365-2664, Vol. 58, no 10, p. 2195-2206Article in journal (Refereed)
    Abstract [en]
    1. In many agricultural landscapes, it is important to restore networks of forests to provide habitat and stepping stones for forest specialist taxa. More knowledge is, however, needed on how to facilitate the immigration of such taxa in restored forest patches. Here, we present the first chronosequence study to quantify the dynamics of immigration credits of forest specialist plants in post-arable forest patches.
    2. We studied the distribution of herbaceous forest specialist plant species in 54 post-arable broadleaved forest patches along gradients of age (20–140 years since forest establishment), distance from ancient forest (0–2,600 m) and patch area (0.5–9.6 ha). With linear mixed models, we estimated the effects of these factors on species richness, patch means of four dispersal-related plant traits and with generalized linear models on the occurrence of 20 individual species.
    3. Post-arable forest patch age and spatial isolation from ancient forest, but not patch size, were important predictors for species richness of forest specialists, suggesting that also small patches are valuable for habitat connectivity. Compared to species richness in ancient forest stands, the immigration credit was reduced by more than 90% after 80 years in post-arable forest patches contiguous to ancient forest compared to 40% after 80 years and 60% after 140 years in isolated patches (at least 100 m to next forest). Tall-growing species with adaptations to long-distance dispersal were faster colonizers, whereas species with heavy diaspores and clonal growth were slower to colonize.
    4. Synthesis and applications. We show that post-arable oak plantations have a high potential for restoration of forest herb vegetation. Dispersal-related plant traits play a key role in explaining interspecific differences among forest specialists. To facilitate forest herb immigration across all functional groups in agricultural landscapes, we suggest to create clusters of relatively small new forest patches nearby older forest with source populations.
  • 20.
    Börjeson, Lowe
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Human Geography.
    Berg, Johan
    Stockholm University, Faculty of Social Sciences, Department of Human Geography.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Jansson, Ulf
    Stockholm University, Faculty of Social Sciences, Department of Human Geography.
    Open Access to Rural Landscapes!2014In: Rural Landscapes: Society, Environment, History, E-ISSN 2002-0104, Vol. 1, no 1, p. 1-2Article in journal (Other academic)
    Abstract [en]

    The academic study of rural landscapes covers a broad range of academic disciplines and thematic, methodological and theoretical concerns and interests; including questions concerned with resource use (e.g. agriculture, forestry, water and mining), settlement, livelihoods, conflicts, conservation, culture and identity. This diversity is clearly a strength (the rich empirical and intellectual base), but also presents a challenge, as the dissemination of research findings is distributed through a plethora of publishing channels, which do not necessarily encourage exchange of results and ideas that are not already perceived as germane to already established academic networks.

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  • 21. Caron, M. M.
    et al.
    De Frenne, P.
    Brunet, J.
    Chabrerie, O.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    De Backer, L.
    Decocq, G.
    Diekmann, M.
    Heinken, T.
    Kolb, A.
    Naaf, T.
    Plue, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Selvi, F.
    Strimbeck, G. R.
    Wulf, M.
    Verheyen, K.
    Interacting effects of warming and drought on regeneration and early growth of Acer pseudoplatanus and A. platanoides2015In: Plant Biology, ISSN 1435-8603, E-ISSN 1438-8677, Vol. 17, no 1, p. 52-62Article in journal (Refereed)
    Abstract [en]

    Climate change is acting on several aspects of plant life cycles, including the sexual reproductive stage, which is considered amongst the most sensitive life-cycle phases. In temperate forests, it is expected that climate change will lead to a compositional change in community structure due to changes in the dominance of currently more abundant forest tree species. Increasing our understanding of the effects of climate change on currently secondary tree species recruitment is therefore important to better understand and forecast population and community dynamics in forests. Here, we analyse the interactive effects of rising temperatures and soil moisture reduction on germination, seedling survival and early growth of two important secondary European tree species, Acer pseudoplatanus and A.platanoides. Additionally, we analyse the effect of the temperature experienced by the mother tree during seed production by collecting seeds of both species along a 2200-km long latitudinal gradient. For most of the responses, A.platanoides showed higher sensitivity to the treatments applied, and especially to its joint manipulation, which for some variables resulted in additive effects while for others only partial compensation. In both species, germination and survival decreased with rising temperatures and/or soil moisture reduction while early growth decreased with declining soil moisture content. We conclude that although A.platanoides germination and survival were more affected after the applied treatments, its initial higher germination and larger seedlings might allow this species to be relatively more successful than A.pseudoplatanus in the face of climate change.

  • 22. Caron, M. M.
    et al.
    De Frenne, P.
    Brunet, J.
    Chabrerie, O.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    De Backer, L.
    Diekmann, M.
    Graae, B. J.
    Heinken, T.
    Kolb, A.
    Naaf, T.
    Plue, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Selvi, F.
    Strimbeck, G. R.
    Wulf, M.
    Verheyen, K.
    Latitudinal variation in seeds characteristics of Acer platanoides and A. pseudoplatanus2014In: Plant Ecology, ISSN 1385-0237, E-ISSN 1573-5052, Vol. 215, no 8, p. 911-925Article in journal (Refereed)
    Abstract [en]

    Climate change will likely affect population dynamics of numerous plant species by modifying several aspects of the life cycle. Because plant regeneration from seeds may be particularly vulnerable, here we assess the possible effects of climate change on seed characteristics and present an integrated analysis of seven seed traits (nutrient concentrations, samara mass, seed mass, wing length, seed viability, germination percentage, and seedling biomass) of Acer platanoides and A. pseudoplatanus seeds collected along a wide latitudinal gradient from Italy to Norway. Seed traits were analyzed in relation to the environmental conditions experienced by the mother trees along the latitudinal gradient. We found that seed traits of A. platanoides were more influenced by the climatic conditions than those of A. pseudoplatanus. Additionally, seed viability, germination percentage, and seedling biomass of A. platanoides were strongly related to the seed mass and nutrient concentration. While A. platanoides seeds were more influenced by the environmental conditions (generally negatively affected by rising temperatures), compared to A. pseudoplatanus, A. platanoides still showed higher germination percentage and seedling biomass than A. pseudoplatanus. Thus, further research on subsequent life-history stages of both species is needed. The variation in seed quality observed along the climatic gradient highlights the importance of studying the possible impact of climate change on seed production and species demography.

  • 23. Caron, M. M.
    et al.
    De Frenne, P.
    Brunet, J.
    Chabrerie, O.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Decocq, G.
    Diekmann, M.
    Graae, B. J.
    Heinken, T.
    Kolb, A.
    Lenoir, J.
    Naaf, T.
    Plue, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Selvi, F.
    Wulf, M.
    Verheyen, K.
    Divergent regeneration responses of two closely related tree species to direct abiotic and indirect biotic effects of climate change2015In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 342, p. 21-29Article in journal (Refereed)
    Abstract [en]

    Changing temperature and precipitation can strongly influence plant reproduction. However, also biotic interactions might indirectly affect the reproduction and recruitment success of plants in the context of climate change. Information about the interactive effects of changes in abiotic and biotic factors is essential, but still largely lacking, to better understand the potential effects of a changing climate on plant populations. Here we analyze the regeneration from seeds of Acer platanoides and Acer pseudoplatanus, two currently secondary forest tree species from seven regions along a 2200 km-wide latitudinal gradient in Europe. We assessed the germination, seedling survival and growth during two years in a common garden experiment where temperature, precipitation and competition with the understory vegetation were manipulated. A. platanoides was more sensitive to changes in biotic conditions while A. pseudoplatanus was affected by both abiotic and biotic changes. In general, competition reduced (in A. platanoides) and warming enhanced (in A. pseudoplatanus) germination and survival, respectively. Reduced competition strongly increased the growth of A. platanoides seedlings. Seedling responses were independent of the conditions experienced by the mother tree during seed production and maturation. Our results indicate that, due to the negative effects of competition on the regeneration of A. platanoides, it is likely that under stronger competition (projected under future climatic conditions) this species will be negatively affected in terms of germination, survival and seedling biomass. Climate-change experiments including both abiotic and biotic factors constitute a key step forward to better understand the response of tree species' regeneration to climate change.

  • 24. Caron, M. M.
    et al.
    De Frenne, P.
    Chabrerie, O.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    De Backer, L.
    Decocq, G.
    Diekmann, M.
    Heinken, T.
    Kolb, A.
    Naaf, T.
    Plue, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Selvi, F.
    Strimbeck, G. R.
    Wulf, M.
    Verheyen, K.
    Impacts of warming and changes in precipitation frequency on the regeneration of two Acer species2015In: Flora: Morphologie, Geobotanik, Oekophysiologie, ISSN 0367-2530, E-ISSN 1618-0585, Vol. 214, p. 24-33Article in journal (Refereed)
    Abstract [en]

    Climate projections indicate that temperatures will increase by up to 4.5 degrees C in Europe by the end of this century, and that more extreme rainfall events and longer intervening dry periods will take place. Climate change will likely affect all phases of the life cycle of plants, but plant reproduction has been suggested to be especially sensitive. Here, using a combination of approaches (soil heaters and different provenances along a latitudinal gradient), we analyzed the regeneration from seeds of Acer platanoides and A. pseudoplatanus, two tree species considered, from a management point of view, of secondary relevance. We studied germination, seedling survival and growth in a full-factorial experiment including warming and changes in watering frequency. Both species responded to warming, watering frequency and seed provenance, with stronger (negative) effects of warming and provenance than of watering frequency. In general, the central provenances performed better than the northernmost and southern-most provenances. We also detected interactive effects between warming, watering frequency and/or seed provenance. Based on these results, both species are expected to show dissimilar responses to the changes in the studied climatic factors, but also the impacts of climate change on the different phases of plant regeneration may differ in direction and magnitude. In general increases in the precipitation, frequency will stimulate germination while warming will reduce survival and growth. Moreover, the frequent divergent responses of seedlings along the latitudinal gradient suggest that climate change will likely have heterogeneous impacts across Europe, with stronger impacts in the northern and southern parts of the species' distribution ranges.

  • 25.
    Chibeya, Doubt
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Wood, Heather
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Cousins, Sara
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Carter, Kerryn
    Nyirenda, Moses Amos
    Maseka, Henry
    How do African elephants utilize the landscape during wet season? A habitat connectivity analysis for Sioma Ngwezi landscape in Zambia2021In: Ecology and Evolution, E-ISSN 2045-7758, Vol. 11, no 21, p. 14916-14931Article in journal (Refereed)
    Abstract [en]
    1. The influence of environmental factors on the distribution and persistence of African elephants (Loxodonta africana) is pertinent to policy makers and managers to formulate balanced plans for different land-use types.
    2. The study focuses on movement of elephants and how they utilize foraging areas in Sioma Ngwezi landscape in Zambia by answering the following questions: (1) Which environmental variables and land-cover class predict the movement of elephants during the wet season in Sioma Ngwezi landscape? (2) What is the wet season suitable habitat for elephants in Sioma Ngwezi landscape? (3) What are the major wet season movement corridors for elephants in Sioma Ngwezi landscape?
    3. We used GPS telemetry data from the collared elephants to assess habitat connectivity. Maximum entropy (MaxEnt) and linkage mapper were the tools used to predict habitat suitability, movement corridors, and barriers in the landscape during the wet season.
    4. The study identified elevation, land cover, and NDVI as the most important environmental predictors that modify the dispersal of elephants in the landscape during the wet season. Additionally, a total of 36 potential wet season corridors were identified connecting 15 core areas mainly used for foraging and protection from poachers in the landscape. Of these, 24 corridors were highly utilized and are suggested as priority corridors for elephant movement in the landscape.
    5. The identified wet season habitats and functional corridors may help to combat elephant poaching by patrolling areas with high relative probability of elephant presence. The findings may also help abate human–elephant conflict such as crop-raiding by managing identified corridors that run into agriculture zones in the game management area.
  • 26.
    Cousins, Sara
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Extinction debt in fragmented grasslands: paid or not?2009In: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 20, no 1, p. 3-7Article in journal (Refereed)
    Abstract [en]

    Fragmentation of grasslands and forests is considered amajor threat to biodiversity. In the case of plants, theeffect of fragmentation or landscape context is still unclearand published results are divergent. One explanation forthis divergence is the slow response of long-lived plants,creating an extinction debt. However, this has not beenempirically confirmed. In this study, data were compiledfrom broad-scale studies of grasslands from throughoutthe world that relate plant diversity to fragmentationeffects. Only seven studies from northern Europe, out ofa total 61, gave any information on actual habitat fragmentationin time and space. In landscapes with 410%grassland remaining, present-day species richness wasrelated to past landscape or habitat pattern. In landscapeswith o10% grassland remaining, in contrast, plant speciesrichness was more related to contemporary landscapeor habitat pattern. Studies from landscapes with 410%grassland remaining supported the concept of an extinctiondebt, while studies from more fragmented landscapesdid not provide any evidence of an extinction debt. Inorder to make generalisations about historical legacies onspecies diversity in grasslands it is important to consider arange of highly transformed landscapes, and not onlylandscapes with a high amount of grassland remaining.

  • 27.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Analysis of land-cover transitions based on 17th and 18th century cadastral maps and aerial photographs2001In: Landscape Ecology, ISSN 0921-2973, E-ISSN 1572-9761, Vol. 16, no 1, p. 41-54Article in journal (Refereed)
    Abstract [en]

    This paper explores the possibility of using non-geometric cadastral maps from the 17th and 18th century together with aerial photographs from 1945 and 1981 to analyse land-cover change in south-east Sweden. Habitats rich in plant species in the European rural landscape seem to be correlated with a long continuity of management. Accurate spatial data from historical data sources are fundamental to understand patterns of vegetation and biodiversity in the present-day landscape. However, traditional methods for rectification of non-geometric maps using corresponding points from orthophotos or modern maps are not satisfying, as internal inaccuracies will remain in the maps. This study presents a method to rectify the maps by local warping, thereby eliminating geometrical irregularities. Further, the land-cover changes were calculated and presented as transition matrices. The extent of arable fields and grasslands were analysed in relation to soil characteristics and continuity of management. The results show a dynamic relation between grassland and arable field, albeit the overall proportions remained almost the same between 17th and 18th centuries: 60% grassland to 32% arable field. The most substantial changes in land-cover were prior to 1945. Today there is 18% grasslands left in the study area, while 56% of the land-cover is arable field. Approximately 8% of present-day land-cover is semi-natural grassland 300 years of age or more. Compared to 300 years ago there is only 1% grassland left on peat and 2% on clay. In contrast, grassland covers associated with bare bedrock have been fairly stable in size. All semi-natural grasslands with a long continuity of management were situated on shallow soils, less than 50 cm depth. The major conclusions from this study are that (i) correctly rectified, old maps are very useful to address questions of land-cover changes in historical time, (ii) general trends in land use over 300 years in this hemi-boreal landscape seem to underestimate the full dynamics of land use change, and (iii) only a small proportion of the semi-natural grassland area had a 300 year continuity of management.

  • 28.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Moving towards the edge: matrix matters!2013In: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 24, no 1, p. 7-8Article in journal (Other academic)
    Abstract [en]

    In this issue of the Journal of Vegetation Science, Chabrerie et al. use plant inventories and geographical data to investigate effects on species richness and turnover caused by management intensity in the surrounding matrix in new and old forest fragments. Although forest edge age was important, more intensive management of the matrix clearly sharpened the edgeinterior gradient.

  • 29.
    Cousins, Sara A. O.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Auffret, Alistair G.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Lindgren, Jessica
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Tränk, Louise
    Regional-scale land-cover change during the 20th century and its consequences for biodiversity2015In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, p. S17-S27Article in journal (Refereed)
    Abstract [en]

    Extensive changes in land cover during the 20th century are known to have had detrimental effects on biodiversity in rural landscapes, but the magnitude of change and their ecological effects are not well known on regional scales. We digitized historical maps from the beginning of the 20th century over a 1652 km(2) study area in southeastern Sweden, comparing it to modern-day land cover with a focus on valuable habitat types. Semi-natural grassland cover decreased by over 96 % in the study area, being largely lost to afforestation and silviculture. Grasslands on finer soils were more likely to be converted into modern grassland or arable fields. However, in addition to remaining semi-natural grassland, today's valuable deciduous forest and wetland habitats were mostly grazed grassland in 1900. An analysis of the landscape-level biodiversity revealed that plant species richness was generally more related to the modern landscape, with grazing management being a positive influence on species richness.

  • 30.
    Cousins, Sara A. O.
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    After the hotspots are gone: land use history and grassland plant species diversity in a strongly transformed agricultural landscape2008In: Applied Vegetation Science, ISSN 1402-2001, E-ISSN 1654-109X, Vol. 11, no 3, p. 365-374Article in journal (Refereed)
    Abstract [en]

    Question: We asked how landscape configuration and present management influence plant species richness and abundance of habitat specialists in grasslands in a ‘modern’ (much exploited and transformed) agricultural Swedish landscape.

    Location: Selaön, south-eastern Sweden (59°24' N, 17°10' E).

    Methods: Present and past (150 and 50 years ago) landscape pattern was analysed in a 25 km2 area. Species richness was investigated in 63 different grassland patches; grazed and abandoned semi-natural grasslands, and grazed ex-arable fields. Influence of landscape variables; area, past and present grassland connectivity, present management on total species richness, density and abundance of 25 grassland specialists was analysed.

    Results: Semi-natural grasslands (permanent unfertilised pastures or meadows formed by traditional agricultural methods) had declined from 60% 150 years ago to 5% today. There was a significant decline in species richness and density in abandoned semi-natural grasslands. Total species richness was influenced by present management, size and connectivity to present and past grassland pattern. Landscape variables did not influence species density in grazed semi-natural grassland suggesting that maintained grazing management makes grassland patches independent of landscape context. The abundance of 16 grassland specialists was mainly influenced by management and to some extent also by landscape variables.

    Conclusion: Although species richness pattern reflect management and to some extent landscape variables, the response of individual species may be idiosyncratic. The historical signal from past landscapes is weak on present-day species richness in highly transformed, agricultural landscapes. Generalizations of historical legacies on species diversity in grasslands should consider also highly transformed landscapes and not only landscapes with a high amount of diversity hotspots left.

  • 31.
    Cousins, Sara A. O.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    The influence of management history and habitat on plant species richness in a rural hemiboreal landscape, Sweden2002In: Landscape Ecology, ISSN 0921-2973, E-ISSN 1572-9761, Vol. 17, no 6, p. 517-529Article in journal (Refereed)
    Abstract [en]

    We explored patterns of plant species richness at different spatial scales in 14 habitats in a Swedish rural landscape. Effects of physical conditions, and relationships between species richness and management history reaching back to the 17 (th) century were examined, using old cadastral maps and aerial photographs. The most species-rich habitats were dry open semi- natural grasslands, midfield islets and road verges. Alpha diversity (species richness within sites) was highest in habitats on dry substrates (excluding bedrock with sparse pines) and beta diversity (species richness among sites) was highest in moist to wet habitats. Alpha and beta components of species richness tended to be inversely related among habitats with similar species richness. Management history influenced diversity patterns. Areas managed as grasslands in the 17 th and 18 th century harboured more species than areas outside the villages. We also found significant relationships between species richness and soil type. Silt proved to be the most species- rich topsoil (10- 20 cm) in addition to thin soils top of on green- or limestone bedrock. The variation in species richness due to local relief or form of the site also showed significant relationships, where flat surfaces had the highest number of species. In contrast, no significant relationship was found between species richness and aspect. Our study suggests that present- day diversity patterns are much influenced by management history, and that small habitat, e. g., road verges and midfield islets, are important for maintaining species richness.

  • 32.
    Cousins, Sara A. O.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Eriksson, Åsa
    Stockholm University, Faculty of Science, Department of Botany.
    Franzen, Daniel
    Stockholm University, Faculty of Science, Department of Botany.
    Reconstructing past land use and vegetation patterns using palaeogeographical and archaeological data: A focus on grasslands in Nynas by the Baltic Sea in south-eastern Sweden2002In: Landscape and Urban Planning, ISSN 0169-2046, E-ISSN 1872-6062, Vol. 61, no 1, p. 1-18Article in journal (Refereed)
    Abstract [en]

    Past landscape characteristics were reconstructed in Nynas, south-eastern Sweden, using geographical and archaeological data together with pollen stratigraphy and an existing shore displacement model, with the aim to explore the development of semi-natural grasslands in the area. A 2.3 m peat core was analysed and radiocarbon dated at three levels. The pollen stratigraphy was estimated to start at approximately 3800 C-14 years before present (BP), at the end of Late Neolithic. Human activities are evident, from both archaeological findings and pollen analysis, for more than 4000 years. Grazing is apparent, possibly more intense around 3200 C-14 years BP, 2500-2600 C-14 years BP, 2100-2200 C-14 years BP, and 1300/1400 C-14 years BP to present day. From 1900+/-80 C-14 years BP and onwards cultivation is intensified at the same time as spruce (Picea abies) expands. Maps on land-cover distribution in the late 17th century was used as a model for the utilisation of the landscape during the Iron Age. Land-covers on very thin soils were grazed and sometimes mown within the village boundaries, but they were also used for cultivation in narrow strips where bedrock is adjacent to clays. Till and varved glacial clays would have been used for cultivation. A reasonable estimation is that 10% of the study area could have been used for cultivation 1900 C-14 years BP, compared to 28% in the end of the 17th century. During the last century there has been a shift towards more arable fields and more forestry. There are 10% open or semi-open grassland left today, and 6% wooded grassland, compared with 47% open or semi-open grassland in the 17th century. Little more than half of the open grasslands are managed today, all by grazing. It is argued that encroachment of trees and shrubs on open or semi-open grasslands will not only reduce species richness in the landscape but also threaten parts of our cultural heritage.

  • 33.
    Cousins, Sara A. O.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Ihse, Margareta
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    A methodological study for biotope and landscape mapping based on CIR aerial photographs1998In: Landscape and Urban Planning, ISSN 0169-2046, E-ISSN 1872-6062, Vol. 41, no 3-4, p. 183-192Article in journal (Refereed)
    Abstract [en]

    In this paper, we present a method for base-line mapping of biotope and landscape elements in the rural Swedish agricultural landscape. The overall goal is to elaborate a classification system for a national landscape monitoring program, based on interpretation of existing colour infrared (CIR) aerial photographs at the scale 1:30000, and including a field control. The classification system developed was tested by mapping landscape elements in strategically selected test areas, and it is assessed with respect to interpretation accuracy. The landscape elements, mapped separately as patches, lines and points, are significant for the biodiversity on landscape level, and are susceptible to change. The classification system is based on a hierarchical approach in five levels, with regard to land use and management, nature type and succession stage, moisture, physiognomy, vegetation cover and plant species. By using the method and the suggested classification system, a base-line mapping can be done very quickly and accurately. The mapping rate is 1.4-2.8 km(2)/h and the interpretation accuracy is 95-99%.

  • 34.
    Cousins, Sara A. O.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Kaligaric, Mitja
    Bakan, Branko
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Political Systems Affect Mobile and Sessile Species Diversity - A Legacy from the Post-WWII Period2014In: PLOS ONE, E-ISSN 1932-6203, Vol. 9, no 8, p. e103367-Article in journal (Refereed)
    Abstract [en]

    Political ideologies, policies and economy affect land use which in turn may affect biodiversity patterns and future conservation targets. However, few studies have investigated biodiversity in landscapes with similar physical properties but governed by different political systems. Here we investigate land use and biodiversity patterns, and number and composition of birds and plants, in the borderland of Austria, Slovenia and Hungary. It is a physically uniform landscape but managed differently during the last 70 years as a consequence of the political map of Europe after World War I and II. We used a historical map from 1910 and satellite data to delineate land use within three 10-kilometre transects starting from the point where the three countries meet. There was a clear difference between countries detectable in current biodiversity patterns, which relates to land use history. Mobile species richness was associated with current land use whereas diversity of sessile species was more associated with past land use. Heterogeneous landscapes were positively and forest cover was negatively correlated to bird species richness. Our results provide insights into why landscape history is important to understand present and future biodiversity patterns, which is crucial for designing policies and conservation strategies across the world.

  • 35.
    Cousins, Sara A. O.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Lavorel, Sandra
    Centre d’Ecologie Fonctionnelle et Ev olutive, CNRS, Montpellier, France.
    Davies, Ian
    Ecosystem Dynamics Group, Research School of Biological Sciences, Australian National University, Australia.
    Modelling the effects of landscape pattern and grazing regimes on the persistence of plant species with high conservation value in grasslands in south-eastern Sweden2003In: Landscape Ecology, ISSN 0921-2973, E-ISSN 1572-9761, Vol. 18, no 3, p. 315-332Article in journal (Refereed)
    Abstract [en]

    Semi-natural grasslands in Sweden are threatened by land-use change and lack of management with attendant risk to their biodiversity. We present a model to explore the effects of grazing frequency and intensity on plant species persistence, and the relative effects of grassland size and pattern. We used a landscape modelling platform, LAMOS (LAndscape MOdelling Shell), to design a landscape model of vegetation dynamics incorporating the effects of local succession, dispersal and grazing disturbance. Five plant functional groups (PFG), representing various combinations of persistence and dispersal character, light requirements and disturbance responses, were defined to model species dynamics. Based on old cadastral maps three different landscapes were designed representing specific time-layers, i.e., a historical (17th to 18th century), a pre-modern (1940s) and a present-day landscape. Simulations showed that a threshold was crossed when grasslands decreased in area to about 10 - 30% of the modelled area, and as a consequence the biomass of grassland-specific PFGs was strongly reduced. These competition sensitive groups did not persist in the model even with intense grazing in the present-day landscape, where grasslands occupy 11% of the total area. However, all grassland species would have been able to persist in the historical landscape, where grasslands occupied 59% of the total area, even without grazing. Our results suggest that continuous but low-intensity grazing is more positive for grassland PFGs than discontinuous but highly intensive grazing. This effect was particularly strong when the frequency and/or intensity of grazing dropped below a threshold of 20%. Simulations using three landscape maps designed to explore effects of further fragmentation and habitat loss showed that the spatial pattern of remaining grasslands is important for the persistence of grassland-specific PFG. The model presented here is an advance towards more realistic grazing models to explore the effects of prescribed grazing and landscape fragmentation on the persistence species or plant functional groups.

  • 36.
    Cousins, Sara A. O.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Assessing changes in plant distribution patterns - indicator species versus plant functional types2004In: Ecological Indicators, ISSN 1470-160X, E-ISSN 1872-7034, Vol. 4, no 1, p. 17-27Article in journal (Refereed)
    Abstract [en]

    To meet conservation goals it is necessary to assess vegetation status and to be able to monitor effects of management and environmental change. In northern Europe grazed grasslands are one of the most threatened habitat in the rural landscape and thus in focus for conservation plans. At present managers use species indicator list to assess past and present management status of grassland and succession stages in particular, as well as effects of the environment. However, these indicators have rarely been scientifically tested. In this study we discuss if plant functional traits may be a key to select suitable indicator species for monitoring land-use change in Swedish rural landscape. The suitability of two possible monitoring tools: (i) plant species selected from functional traits (PFTs) and (ii) indicator species commonly used today to assess grassland management status, were tested along two gradients, a succession gradient and a wetness gradient. We found no association between successional change and plant functional traits, but a response in plant functional traits was found along the wetness gradient. However, the more common non-scientific indicator species responded fairly well to the varying gradient categories along both gradients. We believe that there is a need to further validate the ecological mechanisms behind the present-day indicators and to place them in a geographical context.

  • 37.
    Cousins, Sara A. O.
    et al.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Vanhoenacker, Didrik
    Stockholm University, Faculty of Science, Department of Botany.
    Detection of extinction debt depends on scale and specialisation2011In: Biological Conservation, ISSN 0006-3207, E-ISSN 1873-2917, Vol. 144, no 2, p. 782-787Article in journal (Refereed)
    Abstract [en]

    Many plants can persist in landscapes for a long time after focal habitats have disappeared or become fragmented, which might contribute to an extinction debt. Delayed responses of plant occurrence have recently received great attention, particularly in conservation, although evidence for extinction debts is incongruent. Here we asked if we could detect an extinction debt for plant species after 100 years of fragmentation, depending on regional or local (gamma or alpha respectively) diversity measure used, and if all plant species or only habitat specialists were investigated. Historical and contemporary grassland patterns were analysed in 33 rural landscapes (each 1 km(2) in diameter) in south-eastern Sweden. Results show that managed semi-natural grassland had declined from 39% to 3% in 100 years. Diversity measured at regional scale was best explained by grassland extent 100 years ago, for both all species and grassland specialists. Present-day management, but neither present nor past grassland extent, was important for grassland specialists' occurrence at the local scale, although present-day grassland proportion had a positive influence on species richness at the local scale. We found evidence of an extinction debt at both local and regional scale when all species were included in the analysis, but not for grassland specialist species at the local scale. However, the extinction debt is still to be settled for grassland specialists at the regional scale, and therefore the estimation of extinction debts in fragmented habitats presents one of the greatest challenges for conservation today and in the future.

  • 38. Dahlström, Anna
    et al.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    The History (1620-2003) of Land Use, People and Livestock, and the Relationship to Present Plant Species Diversity in a Rural Landscape in Sweden2006In: Environment and History, ISSN 0967-3407, E-ISSN 1752-7023, Vol. 12, p. 191-212Article in journal (Refereed)
    Abstract [en]

    The traditional agriculture in Europe favoured numerous plant and animal species that are presently declining. Integrated studies based on various sources are needed in order to unravel the complex relationships between changing landscapes and biological diversity. The objectives of this study were to describe changes in land use during c. 350 years in a Swedish agricultural landscape in relation to changes in human population and livestock, and to analyse relationships between historical land use and present-day plant species diversity. There were only minor long-term changes in land use, population and livestock between 1640 and 1854 in the two studied hamlets, but detailed data 1620-41 showed a large short-term fluctuation in livestock numbers. After 1854 larger changes took place. Grasslands were cultivated and livestock composition changed. After 1932, livestock number decreased and most of the former grazed outland (areas located outside the fenced infields) turned into forest by natural succession. 7 per cent of the study area is still grazed semi-natural grassland. The highest plant species richness is today found on semi-natural grassland with a long continuity of grazing. The distribution of five target species suggests that previous land use still has an important effect today. The majority of their occurrences are remnant populations located in previous outland pastures which are today forests.

  • 39. De Frenne, P.
    et al.
    Blondeel, H.
    Brunet, J.
    Caron, M. M.
    Chabrerie, O.
    Cougnon, M.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography. Stockholm Univ, Biogeog & Geomat, Dept Phys Geog, Stockholm, Sweden.
    Decocq, G.
    Diekmann, M.
    Graae, B. J.
    Hanley, M. E.
    Heinken, T.
    Hermy, M.
    Kolb, A.
    Lenoir, J.
    Liira, J.
    Orczewska, A.
    Shevtsova, A.
    Vanneste, T.
    Verheyen, K.
    Atmospheric nitrogen deposition on petals enhances seed quality of the forest herb Anemone nemorosa2018In: Plant Biology, ISSN 1435-8603, E-ISSN 1438-8677, Vol. 20, no 3, p. 619-626Article in journal (Refereed)
    Abstract [en]

    Elevated atmospheric input of nitrogen (N) is currently affecting plant biodiversity and ecosystem functioning. The growth and survival of numerous plant species is known to respond strongly to N fertilisation. Yet, few studies have assessed the effects of N deposition on seed quality and reproductive performance, which is an important life-history stage of plants. Here we address this knowledge gap by assessing the effects of atmospheric N deposition on seed quality of the ancient forest herb Anemone nemorosa using two complementary approaches. By taking advantage of the wide spatiotemporal variation in N deposition rates in pan-European temperate and boreal forests over 2years, we detected positive effects of N deposition on the N concentration (percentage N per unit seed mass, increased from 2.8% to 4.1%) and N content (total N mass per seed more than doubled) of A.nemorosa seeds. In a complementary experiment, we applied ammonium nitrate to aboveground plant tissues and the soil surface to determine whether dissolved N sources in precipitation could be incorporated into seeds. Although the addition of N to leaves and the soil surface had no effect, a concentrated N solution applied to petals during anthesis resulted in increased seed mass, seed N concentration and N content. Our results demonstrate that N deposition on the petals enhances bioaccumulation of N in the seeds of A.nemorosa. Enhanced atmospheric inputs of N can thus not only affect growth and population dynamics via root or canopy uptake, but can also influence seed quality and reproduction via intake through the inflorescences.

  • 40. De Frenne, P
    et al.
    Graae, B J
    Kolb, A
    Brunet, J
    Chabrerie, O
    Cousins, S A O
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Decocq, G
    Dhondt, R
    Diekmann, M
    Eriksson, Ove
    Stockholm University, Faculty of Science, Department of Botany.
    Heinken, T
    Hermy, M
    Jögar, U
    Saguez, R
    Shevtsova, A
    Stanton, S
    Zindel, R
    Zobel, M
    Verheyen, K
    Significant effects of temperature on the reproductive output of the forest herb Anemone nemorosa L.2010In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 259, no 4, p. 809-817Article in journal (Refereed)
    Abstract [en]

    Climate warming is already influencing plant migration in different parts of the world.Numerous modelshave been developed to forecast future plant distributions. Few studies, however, have investigated thepotential effect of warming on the reproductive output of plants. Understorey forest herbs in particular,have received little attention in the debate on climate change impacts.This study focuses on the effect of temperature on sexual reproductive output (number of seeds, seedmass, germination percentage and seedling mass) of Anemone nemorosa L., a model species for slowcolonizing herbaceous forest plants. We sampled seeds of A. nemorosa in populations along a 2400 kmlatitudinal gradient from northern France to northern Sweden during three growing seasons (2005, 2006and 2008). This study design allowed us to isolate the effects of accumulated temperature (GrowingDegree Hours; GDH) from latitude and the local abiotic and biotic environment. Germination and seedsowing trials were performed in incubators, a greenhouse and under field conditions in a forest. Finally,we disentangled correlations between the different reproductive traits of A. nemorosa along thelatitudinal gradient.We found a clear positive relationship between accumulated temperature and seed and seedlingtraits: reproductive output of A. nemorosa improved with increasing GDH along the latitudinal gradient.Seedmass and seedling mass, for instance, increased by 9.7% and 10.4%, respectively, for every 1000 8C hincrease in GDH.Wealso derived strong correlations between several seed and seedling traits both underfield conditions and in incubators. Our results indicate that seed mass, incubator-based germinationpercentage (Germ%Inc) and the output of germinable seeds (product of number of seeds and Germ%Incdivided by 100) from plants grown along a latitudinal gradient (i.e. at different temperature regimes)provide valuable proxies to parameterize key population processes in models.We conclude that (1) climate warming may have a pronounced positive impact on sexualreproduction of A. nemorosa and (2) climate models forecasting plant distributions would benefit fromincluding the temperature sensitivity of key seed traits and population processes.

  • 41. De Frenne, P.
    et al.
    Kolb, A.
    Graae, B. J.
    Decocq, G.
    Baltora, S.
    De Schrijver, A.
    Brunet, J.
    Chabrerie, O.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Dhondt, R.
    Diekmann, M.
    Gruwez, R.
    Heinken, T.
    Hermy, M.
    Liira, J.
    Saguez, R.
    Shevtsova, A.
    Baskin, C. C.
    Verheyen, K.
    A latitudinal gradient in seed nutrients of the forest herb Anemone nemorosa2011In: Plant Biology, ISSN 1435-8603, E-ISSN 1438-8677, Vol. 13, no 3, p. 493-501Article in journal (Refereed)
    Abstract [en]

    The nutrient concentration in seeds determines many aspects of potential success of the sexual reproductive phase of plants, including the seed predation probability, efficiency of seed dispersal and seedling performance. Despite considerable research interest in latitudinal gradients of foliar nutrients, a similar gradient for seeds remains unexplored. We investigated a potential latitudinal gradient in seed nutrient concentrations within the widespread European understorey forest herb Anemone nemorosa L. We sampled seeds of A. nemorosa in 15 populations along a 1900-km long latitudinal gradient at three to seven seed collection dates post-anthesis and investigated the relative effects of growing degree-hours > 5 degrees C, soil characteristics and latitude on seed nutrient concentrations. Seed nitrogen, nitrogen:phosphorus ratio and calcium concentration decreased towards northern latitudes, while carbon:nitrogen ratios increased. When taking differences in growing degree-hours and measured soil characteristics into account and only considering the most mature seeds, the latitudinal decline remained particularly significant for seed nitrogen concentration. We argue that the decline in seed nitrogen concentration can be attributed to northward decreasing seed provisioning due to lower soil nitrogen availability or greater investment in clonal reproduction. This pattern may have large implications for the reproductive performance of this forest herb as the degree of seed provisioning ultimately co-determines seedling survival and reproductive success.

  • 42. De Frenne, Pieter
    et al.
    Baeten, Lander
    Graae, Bente J.
    Brunet, Jorg
    Wulf, Monika
    Orczewska, Anna
    Kolb, Annette
    Jansen, Ivy
    Jamoneau, Aurelien
    Jacquemyn, Hans
    Hermy, Martin
    Diekmann, Martin
    De Schrijver, An
    De Sanctis, Michele
    Decocq, Guillaume
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Verheyen, Kris
    Interregional variation in the floristic recovery of post-agricultural forests2011In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 99, no 2, p. 600-609Article in journal (Refereed)
    Abstract [en]

    1. Worldwide, the floristic composition of temperate forests bears the imprint of past land use for decades to centuries as forests regrow on agricultural land. Many species, however, display significant interregional variation in their ability to (re)colonize post-agricultural forests. This variation in colonization across regions and the underlying factors remain largely unexplored. 2. We compiled data on 90 species and 812 species x study combinations from 18 studies across Europe that determined species' distribution patterns in ancient (i.e. continuously forested since the first available land use maps) and post-agricultural forests. The recovery rate (RR) of species in each landscape was quantified as the log-response ratio of the percentage occurrence in post-agricultural over ancient forest and related to the species-specific life-history traits and local (soil characteristics and light availability) and regional factors (landscape properties as habitat availability, time available for colonization, and climate). 3. For the herb species, we demonstrate a strong (interactive) effect of species' life-history traits and forest habitat availability on the RR of post-agricultural forest. In graminoids, however, none of the investigated variables were significantly related to the RR. 4. The better colonizing species that mainly belonged to the short-lived herbs group showed the largest interregional variability. Their recovery significantly increased with the amount of forest habitat within the landscape, whereas, surprisingly, the time available for colonization, climate, soil characteristics and light availability had no effect. 5. Synthesis. By analysing 18 independent studies across Europe, we clearly showed for the first time on a continental scale that the recovery of short-lived forest herbs increased with the forest habitat availability in the landscape. Small perennial forest herbs, however, were generally unsuccessful in colonizing post-agricultural forest even in relatively densely forested landscapes. Hence, our results stress the need to avoid ancient forest clearance to preserve the typical woodland flora.

  • 43. De Frenne, Pieter
    et al.
    Brunet, Jorg
    Shevtsova, Anna
    Kolb, Annette
    Graae, Bente J.
    Chabrerie, Olivier
    Cousins, Sara Ao
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Decocq, Guillaume
    De Schrijver, An
    Diekmann, Martin
    Gruwez, Robert
    Heinken, Thilo
    Hermy, Martin
    Nilsson, Christer
    Stanton, Sharon
    Tack, Wesley
    Willaert, Justin
    Verheyen, Kris
    Temperature effects on forest herbs assessed by warming and transplant experiments along a latitudinal gradient2011In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 17, no 10, p. 3240-3253Article in journal (Refereed)
    Abstract [en]

    Slow-colonizing forest understorey plants are probably not able to rapidly adjust their distribution range following large-scale climate change. Therefore, the acclimation potential to climate change within their actual occupied habitats will likely be key for their short-and long-term persistence. We combined transplant experiments along a latitudinal gradient with open-top chambers to assess the effects of temperature on phenology, growth and reproductive performance of multiple populations of slow-colonizing understorey plants, using the spring flowering geophytic forb Anemone nemorosa and the early summer flowering grass Milium effusum as study species. In both species, emergence time and start of flowering clearly advanced with increasing temperatures. Vegetative growth (plant height, aboveground biomass) and reproductive success (seed mass, seed germination and germinable seed output) of A. nemorosa benefited from higher temperatures. Climate warming may thus increase future competitive ability and colonization rates of this species. Apart from the effects on phenology, growth and reproductive performance of M. effusum generally decreased when transplanted southwards (e. g., plant size and number of individuals decreased towards the south) and was probably more limited by light availability in the south. Specific leaf area of both species increased when transplanted southwards, but decreased with open-top chamber installation in A. nemorosa. In general, individuals of both species transplanted at the home site performed best, suggesting local adaptation. We conclude that contrasting understorey plants may display divergent plasticity in response to changing temperatures which may alter future understorey community dynamics.

  • 44. De Frenne, Pieter
    et al.
    Graae, Bente J.
    Brunet, Joerg
    Shevtsova, Anna
    De Schrijver, An
    Chabrerie, Olivier
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Decocq, Guillaume
    Diekmann, Martin
    Hermy, Martin
    Heinken, Thilo
    Kolb, Annette
    Nilsson, Christer
    Stanton, Sharon
    Verheyen, Kris
    The response of forest plant regeneration to temperature variation along a latitudinal gradient2012In: Annals of Botany, ISSN 0305-7364, E-ISSN 1095-8290, Vol. 109, no 5, p. 1037-1046Article in journal (Refereed)
    Abstract [en]

    The response of forest herb regeneration from seed to temperature variations across latitudes was experimentally assessed in order to forecast the likely response of understorey community dynamics to climate warming. Seeds of two characteristic forest plants (Anemone nemorosa and Milium effusum) were collected in natural populations along a latitudinal gradient from northern France to northern Sweden and exposed to three temperature regimes in growth chambers (first experiment). To test the importance of local adaptation, reciprocal transplants were also made of adult individuals that originated from the same populations in three common gardens located in southern, central and northern sites along the same gradient, and the resulting seeds were germinated (second experiment). Seedling establishment was quantified by measuring the timing and percentage of seedling emergence, and seedling biomass in both experiments. Spring warming increased emergence rates and seedling growth in the early-flowering forb A. nemorosa. Seedlings of the summer-flowering grass M. effusum originating from northern populations responded more strongly in terms of biomass growth to temperature than southern populations. The above-ground biomass of the seedlings of both species decreased with increasing latitude of origin, irrespective of whether seeds were collected from natural populations or from the common gardens. The emergence percentage decreased with increasing home-away distance in seeds from the transplant experiment, suggesting that the maternal plants were locally adapted. Decreasing seedling emergence and growth were found from the centre to the northern edge of the distribution range for both species. Stronger responses to temperature variation in seedling growth of the grass M. effusum in the north may offer a way to cope with environmental change. The results further suggest that climate warming might differentially affect seedling establishment of understorey plants across their distribution range and thus alter future understorey plant dynamics.

  • 45. De Frenne, Pieter
    et al.
    Graae, Bente J.
    Kolb, Annette
    Shevtsova, Anna
    Baeten, Lander
    Brunet, Jorg
    Chabrerie, Olivier
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography and Quaternary Geology.
    Decocq, Guillaume
    Dhondt, Rob
    Diekmann, Martin
    Gruwez, Robert
    Heinken, Thilo
    Hermy, Martin
    Oster, Mathias
    Saguez, Robert
    Stanton, Sharon
    Tack, Wesley
    Vanhellemont, Margot
    Verheyen, Kris
    An intraspecific application of the leaf-height-seed ecology strategy scheme to forest herbs along a latitudinal gradient2011In: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 34, no 1, p. 132-140Article in journal (Refereed)
    Abstract [en]

    We measured LHS traits in 41 Anemone nemorosa and 44 Milium effusum populations along a 1900-2300 km latitudinal gradient from N France to N Sweden. We then applied multilevel models to identify the effects of regional (temperature, latitude) and local (soil fertility and acidity, overstorey canopy cover) environmental factors on LHS traits. Both species displayed a significant 4% increase in plant height with every degree northward shift (almost a two-fold plant height difference between the southernmost and northernmost populations). Neither seed mass nor SLA showed a significant latitudinal cline. Temperature had a large effect on the three LHS traits of Anemone. Latitude, canopy cover and soil nutrients were related to the SLA and plant height of Milium. None of the investigated variables appeared to be related to the seed mass of Milium. The variation in LHS traits indicates that the ecological strategy determined by the position of each population in this three-factor triangle is not constant along the latitudinal gradient. The significant increase in plant height suggests greater competitive abilities for both species in the northernmost populations. We also found that the studied environmental factors affected the LHS traits of the two species on various scales: spring-flowering Anemone was affected more by temperature, whereas early-summer flowering Milium was affected more by local and other latitude-related factors. Finally, previously reported cross-species correlations between LHS traits and latitude were generally unsupported by our within-species approach.

  • 46. De Pauw, Karen
    et al.
    Depauw, Leen
    Calders, Kim
    Caluwaerts, Steven
    Cousins, Sara
    Stockholm University, Faculty of Science, Department of Physical Geography. Stockholm University, Faculty of Science, The Bolin Centre for Climate Research (together with KTH & SMHI).
    De Lombaerde, Emiel
    Diekmann, Martin
    Frey, David
    Lenoir, Jonathan
    Meeussen, Camille
    Orczewska, Anna
    Plue, Jan
    Spicher, Fabien
    Zellweger, Florian
    Vangansbeke, Pieter
    Verheyen, Kris
    De Frenne, Pieter
    Urban forest microclimates across temperate Europe are shaped by deep edge effects and forest structure2023In: Agricultural and Forest Meteorology, ISSN 0168-1923, E-ISSN 1873-2240, Vol. 341, article id 109632Article in journal (Refereed)
    Abstract [en]

    The urban heat island (UHI) causes strong warming of cities and their urban forests worldwide. Especially urban forest edges are strongly exposed to the UHI effect, which could impact urban forest biodiversity and functioning. However, it is not known to what extent the UHI effect alters edge-to-interior microclimatic gradients within urban forests and whether this depends on the forests' structure.Here we quantified gradients of air temperature, relative air humidity and vapour pressure deficits (VPD) along urban forest edge-to-interior transects with contrasting stand structures in six major cities across Europe. We performed continuous hourly microclimate measurements for two consecutive years and analysed the magnitude and depth of edge effects, as well as forest structural drivers of microclimatic variation.Compared to edge studies in rural temperate forests, we found that edge effects reached deeper into urban forests, at least up to 50 m. Throughout the year, urban forest edges were warmer and drier compared to forest interiors, with the largest differences occurring during summer and daytime. Not only maximum, but also mean and minimum temperatures were higher at the urban forest edge up to large edge distances (at least 85 m). Denser forests with a higher plant area index buffered high air temperatures and VPDs from spring to autumn.We conclude that urban forest edges are unique ecotones with specific microclimates shaped by the UHI effect. Both forest edges and interiors showed increased buffering capacities with higher forest canopy density. We advocate for the conservation and expansion of urban forests which can buffer increasingly frequent and intense climate extremes. To this end, urban forest managers are encouraged to aim for multi-layered dense forest canopies and consider edge buffer zones of at least 50 m wide.

  • 47. De Pauw, Karen
    et al.
    Depauw, Leen
    Calders, Kim
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Decocq, Guillaume
    De Lombaerde, Emiel
    Diekmann, Martin
    Frey, David
    Lenoir, Jonathan
    Meeussen, Camille
    Orczewska, Anna
    Plue, Jan
    Spicher, Fabien
    Zellweger, Florian
    Vangansbeke, Pieter
    Verheyen, Kris
    De Frenne, Pieter
    Nutrient-demanding and thermophilous plants dominate urban forest-edge vegetation across temperate Europe2024In: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 35, no 1, article id e13236Article in journal (Refereed)
    Abstract [en]

    Questions

    Forests are highly fragmented across the globe. For urban forests in particular, fragmentation increases the exposure to local warming caused by the urban heat island (UHI) effect. We here aim to quantify edge effects on herbaceous understorey vegetation in urban forests, and test whether these effects interact with forest structural complexity.

    Location

    We set up a pan-European study at the continental scale including six urban forests in Zurich, Paris, Katowice, Brussels, Bremen, and Stockholm.

    Methods

    We recorded understorey plant communities from the edge towards the interior of urban forests. Within each urban forest, we studied edge-to-interior gradients in paired stands with differing forest structural complexity. Community composition was analysed based on species specialism, life form, light, nutrient, acidity and disturbance indicator values and species' thermal niches.

    Results

    We found that herbaceous communities at urban forest edges supported more generalists and forbs but fewer ferns than in forests' interiors. A buffered summer microclimate proved crucial for the presence of fern species. The edge communities contained more thermophilous, disturbance-tolerant, nutrient-demanding and basiphilous plant species, a pattern strongly confirmed by corresponding edge-to-interior gradients in microclimate, soil and light conditions in the understorey. Additionally, plots with a lower canopy cover and higher light availability supported higher numbers of both generalists and forest specialists. Even though no significant interactions were found between the edge distance and forest structural complexity, opposing additive effects indicated that a dense canopy can be used to buffer negative edge effects.

    Conclusion

    The urban environment poses a multifaceted filter on understorey plant communities which contributes to significant differences in community composition between urban forest edges and interiors. For urban biodiversity conservation and the buffering of edge effects, it will be key to maintain dense canopies near urban forest edges. The urban environment poses a multifaceted filter on understorey plant communities which contributes to significant differences in community composition between urban forest edges and interiors. For urban biodiversity conservation and the buffering of edge effects, it will be key to maintain dense canopies near urban forest edges.image

  • 48. De Pauw, Karen
    et al.
    Depauw, Leen
    Cousins, Sara
    Stockholm University, Faculty of Science, Department of Physical Geography. Stockholm University, Faculty of Science, The Bolin Centre for Climate Research (together with KTH & SMHI).
    De Lombaerde, Emiel
    Diekmann, Martin
    Frey, David
    Kwietniowska, Katarzyna
    Lenoir, Jonathan
    Meeussen, Camille
    Orczewska, Anna
    Plue, Jan
    Spicher, Fabien
    Vanneste, Thomas
    Zellweger, Florian
    Verheyen, Kris
    Vangansbeke, Pieter
    De Frenne, Pieter
    The urban heat island accelerates litter decomposition through microclimatic warming in temperate urban forests2024In: Urban Ecosystems, ISSN 1083-8155, E-ISSN 1573-1642Article in journal (Refereed)
    Abstract [en]

    Forests worldwide are experiencing fragmentation, with especially important consequences for ecosystems bordering urbanized areas. Urban forests are exposed to local warming due to the urban heat island which affects their biodiversity and ecosystem functioning. A key ecosystem function affecting carbon and nutrient cycling in forests is litter decomposition, a process driven by the local microclimate. Thus, our aim was to clarify the impact of the urban heat island on litter decomposition in urban forests. We studied soil microclimate and litter decomposition in six urban forests across Europe and along local gradients from the urban forest edge to the interior. To quantify decomposition independent from local forest composition and litter quality, we used standardized green tea and rooibos tea litterbags. We determined the role of the soil microclimate and other environmental drivers for litter decomposition. Secondly, we assessed effects of edge proximity and landscape context on the soil microclimate. Soil characteristics were only driving green tea and not rooibos tea decomposition. On the contrary, higher soil temperatures resulted in faster rates of litter decomposition for both green and rooibos tea and were related to the proximity to the forest edge and the proportion of built-up area in the landscape. Via structural equation modelling we detected cascading effects of the urban heat island on litter decomposition. Such changes in litter decomposition have the potential to alter the soil food web, nutrient cycling and carbon drawdown in urban forests, and could result in significant interactions between urbanisation and ongoing climate change.

  • 49. De Pauw, Karen
    et al.
    Meeussen, Camille
    Govaert, Sanne
    Sanczuk, Pieter
    Vanneste, Thomas
    Bernhardt-Romermann, Markus
    Bollmann, Kurt
    Brunet, Jorg
    Calders, Kim
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Diekmann, Martin
    Hedwall, Per-Ola
    Iacopetti, Giovanni
    Lenoir, Jonathan
    Lindmo, Sigrid
    Orczewska, Anna
    Ponette, Quentin
    Plue, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography. IVL Swedish Environmental Institute, Sweden.
    Selvi, Federico
    Spicher, Fabien
    Verbeeck, Hans
    Vermeir, Pieter
    Zellweger, Florian
    Verheyen, Kris
    Vangansbeke, Pieter
    De Frenne, Pieter
    Taxonomic, phylogenetic and functional diversity of understorey plants respond differently to environmental conditions in European forest edges2021In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 109, no 7, p. 2629-2648Article in journal (Refereed)
    Abstract [en]
    1. Forest biodiversity world-wide is affected by climate change, habitat loss and fragmentation, and today 20% of the forest area is located within 100 m of a forest edge. Still, forest edges harbour a substantial amount of terrestrial biodiversity, especially in the understorey. The functional and phylogenetic diversity of forest edges have never been studied simultaneously at a continental scale, in spite of their importance for the forests' functioning and for communities' resilience to future change.
    2. We assessed nine metrics of taxonomic, phylogenetic and functional diversity of understorey plant communities in 225 plots spread along edge-to-interior gradients in deciduous forests across Europe. We then derived the relative effects and importance of edaphic, stand and landscape conditions on the diversity metrics.
    3. Here, we show that taxonomic, phylogenetic and functional diversity metrics respond differently to environmental conditions. We report an increase in functional diversity in plots with stronger microclimatic buffering, in spite of their lower taxonomic species richness. Additionally, we found increased taxonomic species richness at the forest edge, but in forests with intermediate and high openness, these communities had decreased phylogenetic diversity.
    4. Functional and phylogenetic diversity revealed complementary and important insights in community assembly mechanisms. Several environmental filters were identified as potential drivers of the patterns, such as a colder macroclimate and less buffered microclimate for functional diversity. For phylogenetic diversity, edaphic conditions were more important. Interestingly, plots with lower soil pH had decreased taxonomic species richness, but led to increased phylogenetic diversity, challenging the phylogenetic niche conservatism concept.
    5. Synthesis. Taxonomic, phylogenetic and functional diversity of understorey communities in forest edges respond differently to environmental conditions, providing insight into different community assembly mechanisms and their interactions. Therefore, it is important to look beyond species richness with phylogenetic and functional diversity approaches when focusing on forest understorey biodiversity.
  • 50. De Pauw, Karen
    et al.
    Sanczuk, Pieter
    Meeussen, Camille
    Depauw, Leen
    De Lombaerde, Emiel
    Govaert, Sanne
    Vanneste, Thomas
    Brunet, Jörg
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Gasperini, Cristina
    Hedwall, Per-Ola
    Iacopetti, Giovanni
    Lenoir, Jonathan
    Plue, Jan
    Selvi, Federico
    Spicher, Fabien
    Uria-Diez, Jaime
    Verheyen, Kris
    Vangansbeke, Pieter
    De Frenne, Pieter
    Forest understorey communities respond strongly to light in interaction with forest structure, but not to microclimate warming2022In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 233, no 1, p. 219-235Article in journal (Refereed)
    Abstract [en]
    • Forests harbour large spatiotemporal heterogeneity in canopy structure. This variation drives the microclimate and light availability at the forest floor. So far, we do not know how light availability and sub-canopy temperature interactively mediate the impact of macroclimate warming on understorey communities.
    • We therefore assessed the functional response of understorey plant communities to warming and light addition in a full factorial experiment installed in temperate deciduous forests across Europe along natural microclimate, light and macroclimate gradients. Furthermore, we related these functional responses to the species’ life-history syndromes and thermal niches.
    • We found no significant community responses to the warming treatment. The light treatment, however, had a stronger impact on communities, mainly due to responses by fast-colonizing generalists and not by slow-colonizing forest specialists. The forest structure strongly mediated the response to light addition and also had a clear impact on functional traits and total plant cover.
    • The effects of short-term experimental warming were small and suggest a time-lag in the response of understorey species to climate change. Canopy disturbance, for instance due to drought, pests or logging, has a strong and immediate impact and particularly favours generalists in the understorey in structurally complex forests.
123 1 - 50 of 142
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