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  • 1. Aalto, Juha
    et al.
    Riihimäki, Henri
    Meineri, Eric
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Luoto, Miska
    Revealing topoclimatic heterogeneity using meteorological station data2017In: International Journal of Climatology, ISSN 0899-8418, E-ISSN 1097-0088, Vol. 37, no Suppl. 1, p. 544-556Article in journal (Refereed)
    Abstract [en]

    Climate is a crucial driver of the distributions and activity of multiple biotic and abiotic processes, and thus high-quality and high-resolution climate data are often prerequisite in various environmental research. However, contemporary gridded climate products suffer critical problems mainly related to sub-optimal pixel size and lack of local topography-driven temperature heterogeneity. Here, by integrating meteorological station data, high-quality terrain information and multivariate modelling, we aim to explicitly demonstrate this deficiency. Monthly average temperatures (1981-2010) from Finland, Sweden and Norway were modelled using generalized additive modelling under (1) a conventional (i.e. considering geographical location, elevation and water cover) and (2) a topoclimatic framework (i.e. also accounting for solar radiation and cold-air pooling). The performance of the topoclimatic model was significantly higher than the conventional approach for most months, with bootstrapped mean R-2 for the topoclimatic model varying from 0.88 (January) to 0.95 (October). The estimated effect of solar radiation was evident during summer, while cold air pooling was identified to improve local temperature estimates in winter. The topoclimatic modelling exposed a substantial temperature heterogeneity within coarser landscape units (>5 degrees C/1 km(-2) in summer) thus unveiling a wide range of potential microclimatic conditions neglected by the conventional approach. Moreover, the topoclimatic model predictions revealed a pronounced asymmetry in average temperature conditions, causing isotherms during summer to differ several hundreds of metres in altitude between the equator and pole facing slopes. In contrast, cold-air pooling in sheltered landscapes lowered the winter temperatures ca. 1.1 degrees C/100m towards the local minimum altitude. Noteworthy, the analysis implies that conventional models produce biassed predictions of long-term average temperature conditions, with errors likely to be high at sites associated with complex topography.

  • 2.
    Ango, Tola Gemechu
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Human Geography.
    Börjeson, Lowe
    Stockholm University, Faculty of Social Sciences, Department of Human Geography.
    Senbeta, Feyera
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Balancing Ecosystem Services and Disservices: Smallholder Farmers' Use and Management of Forest and Trees in an Agricultural Landscape in Southwestern Ethiopia2014In: Ecology & society, ISSN 1708-3087, E-ISSN 1708-3087, Vol. 19, no 1, article id 30Article in journal (Refereed)
    Abstract [en]

    Farmers' practices in the management of agricultural landscapes influence biodiversity with implications for livelihoods, ecosystem service provision, and biodiversity conservation. In this study, we examined how smallholding farmers in an agriculture-forest mosaic landscape in southwestern Ethiopia manage trees and forests with regard to a few selected ecosystem services and disservices that they highlighted as beneficial or problematic. Qualitative and quantitative data were collected from six villages, located both near and far from forest, using participatory field mapping and semistructured interviews, tree species inventory, focus group discussions, and observation. The study showed that farmers' management practices, i.e., the planting of trees on field boundaries amid their removal from inside arable fields, preservation of trees in semimanaged forest coffee, maintenance of patches of shade coffee fields in the agricultural landscape, and establishment of woodlots with exotic trees result in a restructuring of the forest-agriculture mosaic. In addition, the strategies farmers employed to mitigate crop damage by wild mammals such as baboons and bush pigs, e. g., migration and allocation of migrants on lands along forests, have contributed to a reduction in forest and tree cover in the agricultural landscape. Because farmers' management practices were overall geared toward mitigating the negative impact of disservices and to augment positive services, we conclude that it is important to operationalize ecosystem processes as both services and disservices in studies related to agricultural landscapes.

  • 3.
    Ango, Tola Gemechu
    et al.
    Stockholm University, Faculty of Social Sciences, Department of Human Geography.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Börjeson, Lowe
    Stockholm University, Faculty of Social Sciences, Department of Human Geography.
    Drivers and patterns of forest cover change since the late 1950s in southwest Ethiopia: deforestation, agriculture expansion, and coffee productionManuscript (preprint) (Other academic)
  • 4.
    Dahlberg, C. Johan
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Performance of Forest Bryophytes with Different Geographical Distributions Transplanted across a Topographically Heterogeneous Landscape2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 11, article id e112943Article in journal (Refereed)
    Abstract [en]

    Most species distribution models assume a close link between climatic conditions and species distributions. Yet, we know little about the link between species’ geographical distributions and the sensitivity of performance to local environmental factors. We studied the performance of three bryophyte species transplanted at south- and north-facing slopes in a boreal forest landscape in Sweden. At the same sites, we measured both air and ground temperature. We hypothesized that the two southerly distributed species Eurhynchium angustirete and Herzogiella seligeri perform better on south-facing slopes and in warm conditions, and that the northerly distributed species Barbilophozia lycopodioides perform better on north-facing slopes and in relatively cool conditions. The northern, but not the two southern species, showed the predicted relationship with slope aspect. However, the performance of one of the two southern species was still enhanced by warm temperatures. An important reason for the inconsistent results can be that microclimatic gradients across landscapes are complex and influenced by many climate-forcing factors. Therefore, comparing only north- and south-facing slopes might not capture the complexity of microclimatic gradients. Population growth rates and potential distributions are the integrated results of all vital rates. Still, the study of selected vital rates constitutes an important first step to understand the relationship between population growth rates and geographical distributions and is essential to better predict how climate change influences species distributions.

  • 5.
    Dahlberg, C. Johan
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Population dynamics of moss transplants across microclimatic gradientsManuscript (preprint) (Other academic)
    Abstract [en]

    In order to determine the response of a species to climatic change it is important to study how climatic factors influence its vital rates and population growth rate across climatic gradients. We investigated how microclimate influence the population dynamics of transplants from northern and more southern populations of the forest bryophyte Hylocomiastrum umbratum. We predicted that its population growth rate is favored by moist microclimates with colder maximum temperatures, longer snow cover duration and less evaporation, and that annual shoots (segments) will be shorter under drier conditions. We also predicted that northern populations will have higher population growth rate and larger segments than southern populations when transplanted to the northern range. We placed transplants from three northern and three southern populations of H. umbratum at 30 forested sites in central Sweden differing in microclimate. We marked and followed the growth of individual shoots during two years, and calculated population growth rates and stable stage distributions of segment size classes using transition matrix models for northern and southern transplants, respectively, at each locality. Population growth rate was lower and shorter segments developed at sites with higher evaporation, corresponding to our hypothesis. There were no significant difference in population growth rate and stable stage segment length between southern and northern populations. Higher evaporation during the summer result in lower population growth rates of H. umbratum by affecting vital rates, in terms of less segment growth. Both climate change and forestry may alter evaporation conditions across the landscape and, thus, the future distribution of the species.

  • 6.
    Dahlberg, C. Johan
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Fogelström, Elsa
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Population differentiation in timing of development in a forest herb associated with local climate and canopy closureManuscript (preprint) (Other academic)
    Abstract [en]

    Our knowledge of how plant seasonal development is related to local versus larger-scale environmental variation is limited. We investigated differentiation in the timing of vegetative and reproductive development among populations of the forest herb Lathyrus vernus over different spatial scales. We predicted earlier development and shorter development time for populations from a colder, northern region compared to populations from a warmer, southern region. Also, we predicted earlier and shorter development within regions to be associated with colder temperatures and higher proportions of deciduous trees at their sites of origin. Lastly, we predicted that earlier flowering is strongly correlated with earlier start of development. To examine these predictions, we conducted a common garden study, and compared the development of 10 northern and 10 southern Swedish L. vernus populations. Start of development, development time and start of flowering did not differ between populations from the two regions in contrast to our prediction. Within the southern region, start of flowering was earlier in populations from colder sites, while start of development was earlier with colder temperatures within the northern region. Start of flowering occurred earlier in southern populations from sites with higher proportion of deciduous trees. Thus, the prediction for the timing of development within regions was partly confirmed. However, vegetative and reproductive development was not simultaneously influenced by temperature and proportion of deciduous trees within regions, possibly due to the negative correlation between vegetative growth and development time. This implies that earlier start of development or shorter development time not necessarily correspond to earlier start of flowering or vice versa. Overall, the results suggest that smaller scale effects within region, such as temperature and interspecific competition for light, was more important for the timing of development than the larger scale gradients between regions. Lastly, the population differentiation across gradients of temperature and proportion of deciduous trees implies that populations may adapt to long-term changes in light or climatic conditions, and differ in their short-term response to climate change.

  • 7. Dorresteijn, Ine
    et al.
    Schultner, Jannik
    Collier, Neil French
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Senbeta, Feyera
    Fischer, Joern
    Disaggregating ecosystem services and disservices in the cultural landscapes of southwestern Ethiopia: a study of rural perceptions2017In: Landscape Ecology, ISSN 0921-2973, E-ISSN 1572-9761, Vol. 32, no 11, p. 2151-2165Article in journal (Refereed)
    Abstract [en]

    Cultural landscapes provide essential ecosystem services to local communities, especially in poor rural settings. However, potentially negative impacts of ecosystems-or disservices-remain inadequately understood. Similarly, how benefit-cost outcomes differ within communities is unclear, but potentially important for cultural landscape management. Here we investigated whether distinct forest ecosystem service-disservice outcomes emerge within local communities. We aimed to characterize groups of community members according to service-disservice outcomes, and assessed their attitudes towards the forest. We interviewed 150 rural households in southwestern Ethiopia about locally relevant ecosystem services (provisioning services) and disservices (wildlife impacts). Households were grouped based on their ecosystem service-disservice profiles through hierarchical clustering. We used linear models to assess differences between groups in geographic and socioeconomic characteristics, as well as attitudes toward the forest. We identified three groups with distinct ecosystem service-disservice profiles. Half of the households fell into a lose-lose profile (low benefits, high costs), while fewer had lose-escape (low benefits, low costs) and win-lose (high benefits, high costs) profiles. Location relative to forest and altitude explained differences between the lose-escape profile and other households. Socioeconomic factors were also important. Win-lose households appeared to be wealthier and had better forest use rights compared to lose-lose households. Attitudes towards the forest did not differ between profiles. Our study demonstrates the importance of disaggregating both ecosystem services and disservices, instead of assuming that communities receive benefits and costs homogenously. To manage cultural landscapes sustainably, such heterogeneity must be acknowledged and better understood.

  • 8. Ellis, L. T.
    et al.
    Aleffi, M.
    Asthana, A. K.
    Srivastava, A.
    Bakalin, V. A.
    Batan, N.
    Ozdemir, T.
    Bednarek-Ochyra, H.
    Borovichev, E. A.
    Brugues, M.
    Cano, M. J.
    Choi, S. S.
    De Beer, D.
    Eckstein, J.
    Erzberger, P.
    Fedosov, V. E.
    Ganeva, A.
    Natcheva, R.
    Garcia, C. A.
    Sergio, C.
    Garilleti, R.
    Albertos, B.
    Puche, F.
    Guecel, S.
    Higuchi, M.
    Hugonnot, V.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Kirmaci, M.
    Aslan, G.
    Koponen, T.
    Lara, F.
    Mazimpaka, V.
    van Melick, H.
    Mueller, F.
    Kiremit, H. Ozenoglu
    Papp, B.
    Szurdoki, E.
    Plasek, V.
    Cihal, L.
    van der Pluijm, A.
    Poponessi, S.
    Mariotti, M. G.
    Reyniers, J.
    Sabovljevic, M. S.
    Sawicki, J.
    Smith, V. R.
    Stebel, A.
    Stefanut, S.
    Sun, B. -Y
    Vana, J.
    Venanzoni, R.
    New national and regional bryophyte records, 402014In: Journal of Bryology, ISSN 0373-6687, E-ISSN 1743-2820, Vol. 36, no 3, p. 223-U98Article in journal (Refereed)
  • 9.
    Elmhagen, Bodil
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Destouni, Georgia
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Angerbjörn, Anders
    Stockholm University, Faculty of Science, Department of Zoology.
    Borgström, Sara
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Boyd, Emily
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. University of Reading, England.
    Cousins, Sara A. O.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Dalen, Love
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Physical Geography. Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ermold, Matti
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hedlund, Johanna
    Stockholm University, Faculty of Science, Department of Zoology.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Jaramillo, Fernando
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Lagerholm, Vendela K.
    Stockholm University, Faculty of Science, Department of Zoology. Swedish Museum of Natural History, Sweden.
    Lyon, Steve W.
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Moor, Helen
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Nykvist, Björn
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Stockholm University, Stockholm Environment Institute.
    Pasanen-Mortensen, Marianne
    Stockholm University, Faculty of Science, Department of Zoology.
    Plue, Jan
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Prieto, Carmen
    Stockholm University, Faculty of Science, Department of Physical Geography.
    van der Velde, Ype
    Stockholm University, Faculty of Science, Department of Physical Geography. Wageningen University & Research Center, Netherlands.
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Interacting effects of change in climate, human population, land use, and water use on biodiversity and ecosystem services2015In: Ecology & society, ISSN 1708-3087, E-ISSN 1708-3087, Vol. 20, no 1, article id UNSP 23Article in journal (Refereed)
    Abstract [en]

    Human population growth and resource use, mediated by changes in climate, land use, and water use, increasingly impact biodiversity and ecosystem services provision. However, impacts of these drivers on biodiversity and ecosystem services are rarely analyzed simultaneously and remain largely unknown. An emerging question is how science can improve the understanding of change in biodiversity and ecosystem service delivery and of potential feedback mechanisms of adaptive governance. We analyzed past and future change in drivers in south-central Sweden. We used the analysis to identify main research challenges and outline important research tasks. Since the 19th century, our study area has experienced substantial and interlinked changes; a 1.6 degrees C temperature increase, rapid population growth, urbanization, and massive changes in land use and water use. Considerable future changes are also projected until the mid-21st century. However, little is known about the impacts on biodiversity and ecosystem services so far, and this in turn hampers future projections of such effects. Therefore, we urge scientists to explore interdisciplinary approaches designed to investigate change in multiple drivers, underlying mechanisms, and interactions over time, including assessment and analysis of matching-scale data from several disciplines. Such a perspective is needed for science to contribute to adaptive governance by constantly improving the understanding of linked change complexities and their impacts.

  • 10. Fenton, Nicole J.
    et al.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Pharo, Emma J.
    Bryophytes in Forest Ecosystems2015In: Routledge Handbook of Forest Ecology / [ed] Kelvin S.-H. Peh, Richard T. Corlett, Yves Bergeron, London: Routledge, 2015, p. 239-249Chapter in book (Refereed)
  • 11. Fischer, Joern
    et al.
    Abson, David J.
    Bergsten, Arvid
    Collier, Neil French
    Dorresteijn, Ine
    Hanspach, Jan
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Schultner, Jannik
    Senbeta, Feyera
    Reframing the Food-Biodiversity Challenge2017In: Trends in Ecology & Evolution, ISSN 0169-5347, E-ISSN 1872-8383, Vol. 32, no 5, p. 335-345Article, review/survey (Refereed)
    Abstract [en]

    Given the serious limitations of production-oriented frameworks, we offer here a new conceptual framework for how to analyze the nexus of food security and biodiversity conservation. We introduce four archetypes of social-ecological system states corresponding to win-win (e.g., agroecology), win-lose (e.g., intensive agriculture), lose-win (e.g., fortress conservation), and lose-lose (e.g., degraded landscapes) outcomes for food security and biodiversity conservation. Each archetype is shaped by characteristic external drivers, exhibits characteristic internal social-ecological features, and has characteristic feedbacks that maintain it. This framework shifts the emphasis from focusing on production only to considering social-ecological dynamics, and enables comparison among landscapes. Moreover, examining drivers and feedbacks facilitates the analysis of possible transitions between system states (e.g., from a lose-lose outcome to a more preferred outcome).

  • 12. Fischer, Joern
    et al.
    Abson, David J.
    Bergsten, Arvid
    Collier, Neil French
    Dorresteijn, Ine
    Hanspach, Jan
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Schultner, Jannik
    Senbeta, Feyera
    We Need Qualitative Progress to Address the Food-Biodiversity Nexus: A Reply to Seppelt et al.2017In: Trends in Ecology & Evolution, ISSN 0169-5347, E-ISSN 1872-8383, Vol. 32, no 9, p. 632-633Article in journal (Refereed)
  • 13.
    Gove, Aaron D.
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Botany.
    Nemomissa, Sileshi
    Shimelis, Anteneh
    Enkossa, Woldeyohannes
    Structurally complex farms support high avian functional diversity in tropical montane Ethiopia2013In: Journal of Tropical Ecology, ISSN 0266-4674, E-ISSN 1469-7831, Vol. 29, p. 87-97Article in journal (Refereed)
    Abstract [en]

    Of all feeding guilds, understorey insectivores are thought to be most sensitive to disturbance and forest conversion. We compared the composition of bird feeding guilds in tropical forest fragments with adjacent agro-ecosystems in a montane region of south-west Ethiopia. We used a series of point counts to survey birds in 19 agriculture and 19 forest sites and recorded tree species within each farm across an area of 40 x 35 km. Insectivores (similar to 17 spp. per plot), frugivores (similar to 3 spp. per plot) and omnivores (similar to 5 spp. per plot) maintained species density across habitats, while granivores and nectarivores increased in the agricultural sites by factors of 7 and 3 respectively. Species accumulation curves of each guild were equal or steeper in agriculture, suggesting that agricultural and forest landscapes were equally heterogeneous for all bird guilds. Counter to most published studies, we found no decline in insectivore species richness with forest conversion. However, species composition differed between the two habitats, with certain forest specialists replaced by other species within each feeding guild. We suggest that the lack of difference in insectivorous species numbers between forest and agriculture in this region is due to the benign nature of the agricultural habitat, but also due to a regional species pool which contains many bird species which are adapted to open habitats.

  • 14. Gove, A.D.
    et al.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Botany. Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Nemomissa, Sileshi
    Shimelis, A.
    Ethiopian coffee cultivation: Implications for bird conservation and environmental certification2008In: Conservation Letters, Vol. 1, p. 208-216Article in journal (Refereed)
  • 15.
    Greiser, Caroline
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Meineri, Eric
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Marseille University, France.
    Luoto, Miska
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Monthly microclimate models in a managed boreal forest landscape2018In: Agricultural and Forest Meteorology, ISSN 0168-1923, E-ISSN 1873-2240, Vol. 250-251, p. 147-158Article in journal (Refereed)
    Abstract [en]

    The majority of microclimate studies have been done in topographically complex landscapes to quantify and predict how near-ground temperatures vary as a function of terrain properties. However, in forests understory temperatures can be strongly influenced also by vegetation. We quantified the relative influence of vegetation features and physiography (topography and moisture-related variables) on understory temperatures in managed boreal forests in central Sweden. We used a multivariate regression approach to relate near-ground temperature of 203 loggers over the snow-free seasons in an area of ∼16,000 km2 to remotely sensed and on-site measured variables of forest structure and physiography. We produced climate grids of monthly minimum and maximum temperatures at 25 m resolution by using only remotely sensed and mapped predictors. The quality and predictions of the models containing only remotely sensed predictors (MAP models) were compared with the models containing also on-site measured predictors (OS models). Our data suggest that during the warm season, where landscape microclimate variability is largest, canopy cover and basal area were the most important microclimatic drivers for both minimum and maximum temperatures, while physiographic drivers (mainly elevation) dominated maximum temperatures during autumn and early winter. The MAP models were able to reproduce findings from the OS models but tended to underestimate high and overestimate low temperatures. Including important microclimatic drivers, particularly soil moisture, that are yet lacking in a mapped form should improve the microclimate maps. Because of the dynamic nature of managed forests, continuous updates of mapped forest structure parameters are needed to accurately predict temperatures. Our results suggest that forest management (e.g. stand size, structure and composition) and conservation may play a key role in amplifying or impeding the effects of climate-forcing factors on near-ground temperature and may locally modify the impact of global warming.

  • 16. Haenke, Hendrik
    et al.
    Börjeson, Lowe
    Stockholm University, Faculty of Social Sciences, Department of Human Geography.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Enfors-Kautsky, Elin
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Drought tolerant species dominate as rainfall and tree cover returns in the West African Sahel2016In: Land use policy, ISSN 0264-8377, E-ISSN 1873-5754, Vol. 59, p. 111-120Article in journal (Refereed)
    Abstract [en]

    After the severe droughts in the 1970s and 1980s, and subsequent debates about desertification, analyses of satellite images reveal that the West African Sahel has become greener again. In this paper we report a study on changes in tree cover and tree species composition in three village landscapes in northern Burkina Faso, based on a combination of methods: tree density change detection using aerial photos and satellite images, a tree species inventory including size class distribution analysis, and interviews with local farmers about woody vegetation changes. Our results show a decrease in tree cover in the 1970s followed by an increase since the mid-1980s, a pattern correlating with the temporal trends in rainfall as well as remotely sensed greening in the region. However, both the inventory and interview data shows that the species composition has changed substantially towards a higher dominance of drought-resistant and exotic species. This shift, occurring during a period of increasing annual precipitation, points to the complexity of current landscape changes and questions rain as the sole primary driver of the increase in tree cover. We propose that the observed changes in woody vegetation (densities, species composition and spatial distribution) are mediated by changes in land use, including intensification and promotion of drought tolerant and fast growing species. Our findings, which indicate a rather surprising trajectory of land cover change, highlight the importance of studies that integrate evidence of changes in tree density and species composition to complement our understanding of land use and vegetation change trajectories in the Sahel obtained from satellite images. We conclude that a better understanding of the social-ecological relations and emerging land use trajectories that produce new types of agroforestry parklands in the region is of crucial importance for designing suitable policies for climate change adaptation, biodiversity conservation and the sustainable delivery of ecosystem services that benefit local livelihoods in one of the world's poorest regions.

  • 17. Harper, Karen A.
    et al.
    Macdonald, S. Ellen
    Mayerhofer, Michael S.
    Biswas, Shekhar R.
    Esseen, Per-Anders
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Stewart, Katherine J.
    Mallik, Azim U.
    Drapeau, Pierre
    Jonsson, Bengt-Gunnar
    Lesieur, Daniel
    Kouki, Jari
    Bergeron, Yves
    Edge influence on vegetation at natural and anthropogenic edges of boreal forests in Canada and Fennoscandia2015In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 103, no 3, p. 550-562Article in journal (Refereed)
    Abstract [en]

    Although anthropogenic edges are an important consequence of timber harvesting, edges due to natural disturbances or landscape heterogeneity are also common. Forest edges have been well studied in temperate and tropical forests, but less so in less productive, disturbance-adapted boreal forests. We synthesized data on forest vegetation at edges of boreal forests and compared edge influence among edge types (fire, cut, lake/wetland; old vs. young), forest types (broadleaf vs. coniferous) and geographic regions. Our objectives were to quantify vegetation responses at edges of all types and to compare the strength and extent of edge influence among different types of edges and forests. Research was conducted using the same general sampling design in Alberta, Ontario and Quebec in Canada, and in Sweden and Finland. We conducted a meta-analysis for a variety of response variables including forest structure, deadwood abundance, regeneration, understorey abundance and diversity, and non-vascular plant cover. We also determined the magnitude and distance of edge influence (DEI) using randomization tests. Some edge responses (lower tree basal area, tree canopy and bryophyte cover; more logs; higher regeneration) were significant overall across studies. Edge influence on ground vegetation in boreal forests was generally weak, not very extensive (DEI usually <20m) and decreased with time. We found more extensive edge influence at natural edges, at younger edges and in broadleaf forests. The comparison among regions revealed weaker edge influence in Fennoscandian forests.Synthesis. Edges created by forest harvesting do not appear to have as strong, extensive or persistent influence on vegetation in boreal as in tropical or temperate forested ecosystems. We attribute this apparent resistance to shorter canopy heights, inherent heterogeneity in boreal forests and their adaptation to frequent natural disturbance. Nevertheless, notable differences between forest structure responses to natural (fire) and anthropogenic (cut) edges raise concerns about biodiversity implications of extensive creation of anthropogenic edges. By highlighting universal responses to edge influence in boreal forests that are significant irrespective of edge or forest type, and those which vary by edge type, we provide a context for the conservation of boreal forests.

  • 18. Hudson, Lawrence N.
    et al.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Samnegård, Ulrika
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Lund University, Sweden.
    The database of the PREDICTS (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems) project2017In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 7, no 1, p. 145-188Article in journal (Refereed)
    Abstract [en]

    The PREDICTS project-Projecting Responses of Ecological Diversity In Changing Terrestrial Systems (www.predicts.org.uk)-has collated from published studies a large, reasonably representative database of comparable samples of biodiversity from multiple sites that differ in the nature or intensity of human impacts relating to land use. We have used this evidence base to develop global and regional statistical models of how local biodiversity responds to these measures. We describe and make freely available this 2016 release of the database, containing more than 3.2 million records sampled at over 26,000 locations and representing over 47,000 species. We outline how the database can help in answering a range of questions in ecology and conservation biology. To our knowledge, this is the largest and most geographically and taxonomically representative database of spatial comparisons of biodiversity that has been collated to date; it will be useful to researchers and international efforts wishing to model and understand the global status of biodiversity.

  • 19. Hudson, Lawrence N.
    et al.
    Newbold, Tim
    Contu, Sara
    Hill, Samantha L. L.
    Lysenko, Igor
    De Palma, Adriana
    Phillips, Helen R. P.
    Senior, Rebecca A.
    Bennett, Dominic J.
    Booth, Hollie
    Choimes, Argyrios
    Correia, David L. P.
    Day, Julie
    Echeverria-Londono, Susy
    Garon, Morgan
    Harrison, Michelle L. K.
    Ingram, Daniel J.
    Jung, Martin
    Kemp, Victoria
    Kirkpatrick, Lucinda
    Martin, Callum D.
    Pan, Yuan
    White, Hannah J.
    Aben, Job
    Abrahamczyk, Stefan
    Adum, Gilbert B.
    Aguilar-Barquero, Virginia
    Aizen, Marcelo A.
    Ancrenaz, Marc
    Arbelaez-Cortes, Enrique
    Armbrecht, Inge
    Azhar, Badrul
    Azpiroz, Adrian B.
    Baeten, Lander
    Baldi, Andras
    Banks, John E.
    Barlow, Jos
    Batary, Peter
    Bates, Adam J.
    Bayne, Erin M.
    Beja, Pedro
    Berg, Ake
    Berry, Nicholas J.
    Bicknell, Jake E.
    Bihn, Jochen H.
    Boehning-Gaese, Katrin
    Boekhout, Teun
    Boutin, Celine
    Bouyer, Jeremy
    Brearley, Francis Q.
    Brito, Isabel
    Brunet, Joerg
    Buczkowski, Grzegorz
    Buscardo, Erika
    Cabra-Garcia, Jimmy
    Calvino-Cancela, Maria
    Cameron, Sydney A.
    Cancello, Eliana M.
    Carrijo, Tiago F.
    Carvalho, Anelena L.
    Castro, Helena
    Castro-Luna, Alejandro A.
    Cerda, Rolando
    Cerezo, Alexis
    Chauvat, Matthieu
    Clarke, Frank M.
    Cleary, Daniel F. R.
    Connop, Stuart P.
    D'Aniello, Biagio
    da Silva, Pedro Giovani
    Darvill, Ben
    Dauber, Jens
    Dejean, Alain
    Diekoetter, Tim
    Dominguez-Haydar, Yamileth
    Dormann, Carsten F.
    Dumont, Bertrand
    Dures, Simon G.
    Dynesius, Mats
    Edenius, Lars
    Elek, Zoltan
    Entling, Martin H.
    Farwig, Nina
    Fayle, Tom M.
    Felicioli, Antonio
    Felton, Annika M.
    Ficetola, Gentile F.
    Filgueiras, Bruno K. C.
    Fonte, Steven J.
    Fraser, Lauchlan H.
    Fukuda, Daisuke
    Furlani, Dario
    Ganzhorn, Joerg U.
    Garden, Jenni G.
    Gheler-Costa, Carla
    Giordani, Paolo
    Giordano, Simonetta
    Gottschalk, Marco S.
    Goulson, Dave
    Gove, Aaron D.
    Grogan, James
    Hanley, Mick E.
    Hanson, Thor
    Hashim, Nor R.
    Hawes, Joseph E.
    Hebert, Christian
    Helden, Alvin J.
    Henden, John-Andre
    Hernandez, Lionel
    Herzog, Felix
    Higuera-Diaz, Diego
    Hilje, Branko
    Horgan, Finbarr G.
    Horvath, Roland
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Isaacs-Cubides, Paola
    Ishitani, Masahiro
    Jacobs, Carmen T.
    Jaramillo, Victor J.
    Jauker, Birgit
    Jonsell, Mats
    Jung, Thomas S.
    Kapoor, Vena
    Kati, Vassiliki
    Katovai, Eric
    Kessler, Michael
    Knop, Eva
    Kolb, Annette
    Koroesi, Adam
    Lachat, Thibault
    Lantschner, Victoria
    Le Feon, Violette
    LeBuhn, Gretchen
    Legare, Jean-Philippe
    Letcher, Susan G.
    Littlewood, Nick A.
    Lopez-Quintero, Carlos A.
    Louhaichi, Mounir
    Loevei, Gabor L.
    Lucas-Borja, Manuel Esteban
    Luja, Victor H.
    Maeto, Kaoru
    Magura, Tibor
    Mallari, Neil Aldrin
    Marin-Spiotta, Erika
    Marshall, E. J. P.
    Martinez, Eliana
    Mayfield, Margaret M.
    Mikusinski, Grzegorz
    Milder, Jeffrey C.
    Miller, James R.
    Morales, Carolina L.
    Muchane, Mary N.
    Muchane, Muchai
    Naidoo, Robin
    Nakamura, Akihiro
    Naoe, Shoji
    Nates-Parra, Guiomar
    Navarrete Gutierrez, Dario A.
    Neuschulz, Eike L.
    Noreika, Norbertas
    Norfolk, Olivia
    Noriega, Jorge Ari
    Noeske, Nicole M.
    O'Dea, Niall
    Oduro, William
    Ofori-Boateng, Caleb
    Oke, Chris O.
    Osgathorpe, Lynne M.
    Paritsis, Juan
    Parra-H, Alejandro
    Pelegrin, Nicolas
    Peres, Carlos A.
    Persson, Anna S.
    Petanidou, Theodora
    Phalan, Ben
    Philips, T. Keith
    Poveda, Katja
    Power, Eileen F.
    Presley, Steven J.
    Proenca, Vania
    Quaranta, Marino
    Quintero, Carolina
    Redpath-Downing, Nicola A.
    Reid, J. Leighton
    Reis, Yana T.
    Ribeiro, Danilo B.
    Richardson, Barbara A.
    Richardson, Michael J.
    Robles, Carolina A.
    Roembke, Joerg
    Romero-Duque, Luz Piedad
    Rosselli, Loreta
    Rossiter, Stephen J.
    Roulston, T'ai H.
    Rousseau, Laurent
    Sadler, Jonathan P.
    Safian, Szabolcs
    Saldana-Vazquez, Romeo A.
    Samnegård, Ulrika
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Schueepp, Christof
    Schweiger, Oliver
    Sedlock, Jodi L.
    Shahabuddin, Ghazala
    Sheil, Douglas
    Silva, Fernando A. B.
    Slade, Eleanor M.
    Smith-Pardo, Allan H.
    Sodhi, Navjot S.
    Somarriba, Eduardo J.
    Sosa, Ramon A.
    Stout, Jane C.
    Struebig, Matthew J.
    Sung, Yik-Hei
    Threlfall, Caragh G.
    Tonietto, Rebecca
    Tothmeresz, Bela
    Tscharntke, Teja
    Turner, Edgar C.
    Tylianakis, Jason M.
    Vanbergen, Adam J.
    Vassilev, Kiril
    Verboven, Hans A. F.
    Vergara, Carlos H.
    Vergara, Pablo M.
    Verhulst, Jort
    Walker, Tony R.
    Wang, Yanping
    Watling, James I.
    Wells, Konstans
    Williams, Christopher D.
    Willig, Michael R.
    Woinarski, John C. Z.
    Wolf, Jan H. D.
    Woodcock, Ben A.
    Yu, Douglas W.
    Zaitsev, Andrey S.
    Collen, Ben
    Ewers, Rob M.
    Mace, Georgina M.
    Purves, Drew W.
    Scharlemann, Joern P. W.
    Purvis, Andy
    The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts2014In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 4, no 24, p. 4701-4735Article in journal (Refereed)
    Abstract [en]

    Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species' threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project - and avert - future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups - including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems - ). We make site-level summary data available alongside this article. The full database will be publicly available in 2015.

  • 20.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Botany.
    Riparian zones increase regional species richness by harboring different, not more, species: comment.2006In: Ecology, ISSN 0012-9658, Vol. 87, no 8, p. 2126-2128Article in journal (Refereed)
  • 21.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Botany.
    The response of land snail assemblages below aspens to forest fire and clear-cutting in Fennoscandian boreal forests2011In: Forest Ecology and Management, ISSN 0378-1127, E-ISSN 1872-7042, Vol. 261, no 11, p. 1811-1819Article in journal (Refereed)
    Abstract [en]

    Species can persist in a landscape with recurrent disturbances either through local survival or by dispersing to sites of a preferred successional stage. This study investigated in what extent forest floor dwelling land snails survived forest fires and clear-cutting. Snail fauna in LFH (litter, fermenting litter and humus) samples below retained aspen trees in disturbed areas were compared with samples under scattered aspens in adjacent forests by extracting snails from LFH samples below five aspens in several stands of each type (five forest fires, six clear-cuts, and seven undisturbed forests). LFH samples from burnt sites had a higher pH than from forests, but on average a lower abundance of individual snails (11 vs. 30 in 0.5 I LFH) and 50% lower species density (3 vs. 6 species). The abundances and species densities in the clear-cuts were less affected. There was generally a positive relationship between pH and both species density and abundance in all the stand types. Burning apparently depleted the snail fauna considerably and some species may be dependent on dispersal if they are to recover within the burnt area, while the snail assemblages at clear-cuts did not differ significantly in species composition from adjacent forests. The positive relationship between pH and snail prevalence on the burnt sites raises questions regarding the pre- and post-fire spatial variation in pH (and available minerals) within and among stands and how it relates to snail survival rates and their capacity to track suitable places after the disturbance. Retained aspens at clear-cuts seem to harbour a forest like land snail fauna.

  • 22.
    Hylander, Kristoffer
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ehrlen, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    The mechanisms causing extinction debts2013In: Trends in Ecology & Evolution, ISSN 0169-5347, E-ISSN 1872-8383, Vol. 28, no 6, p. 341-346Article in journal (Refereed)
    Abstract [en]

    Extinction debts can result from many types of habitat changes involving mechanisms other than metapopulation processes. This is a fact that most recent literature on extinction debts pays little attention to. We argue that extinction debts can arise because (i) individuals survive in resistant life-cycle stages long after habitat quality change, (ii) stochastic extinctions of populations that have become small are not immediate, and (iii) metapopulations survive long after that connectivity has decreased if colonization-extinction dynamics is slow. A failure to distinguish between these different mechanisms and to simultaneously consider both the size of the extinction debt and the relaxation time hampers our understanding of how extinction debts arise and our ability to prevent ultimate extinctions.

  • 23.
    Hylander, Kristoffer
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ehrlén, Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Luoto, Miska
    Meineri, Eric
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Microrefugia: Not for everyone2015In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, p. s60-S68Article in journal (Refereed)
    Abstract [en]

    Microrefugia are sites that support populations of species when their ranges contract during unfavorable climate episodes. Here, we review and discuss two aspects relevant for microrefugia. First, distributions of different species are influenced by different climatic variables. Second, climatic variables differ in the degree of local decoupling from the regional climate. Based on this, we suggest that only species limited by climatic conditions decoupled from the regional climate can benefit from microrefugia. We argue that this restriction has received little attention in spite of its importance for microrefugia as a mechanism for species resilience (the survival of unfavorable episodes and subsequent range expansion). Presence of microrefugia will depend on both the responses of individual species to local climatic variation and how climate-forcing factors shape the correlation between local and regional climate across space and time.

  • 24.
    Hylander, Kristoffer
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Johnson, Samuel
    Stockholm University, Faculty of Science, Department of Botany.
    In situ survival of forest bryophytes in small-scale refugia after an intense forest fire2010In: Journal of Vegetation Science, ISSN 1100-9233, E-ISSN 1654-1103, Vol. 21, no 6, p. 1099-1109Article in journal (Refereed)
    Abstract [en]

    Question Species can persist in landscapes with recurring disturbances either by migrating to places suitable for the moment or by enduring the threatening conditions. We investigated to what extent boreal forest bryophytes survived an intense forest fire in situ and whether bryophytes had started to recolonize the area 7-8 years later. Location Tyresta National Park, eastern Sweden. Methods We recorded bryophytes in 14 burnt and 12 forest reference plots (50 x 50 m). In each plot we investigated 15 random 1-m2 micro-plots. In plots in the burnt area we also examined micro-plots at locations of all fire refugia, and in case of the forest references, of 10 potential refugia. Results We found on average three small refugia per 50 x 50-m plot; each containing on average 4.8 forest bryophytes, a level similar to that of micro-plots in the references, but significantly higher than in random micro-plots in the burnt plots (1.5 species). Many refugia were located in rocky areas, but few were in wet sites. The burnt area remained dominated by a few fire-favoured species, even if recolonization of forest bryophytes had begun. There was, however, no significant correlation between number of refugia and number of forest species in random micro-plots, leaving open the question of the importance of refugia as regulators of early succession. Conclusion We conclude that small-scale refugia can also occur for sensitive species such as forest bryophytes, and that the refugia in our case were frequently found on rocky or mesic rather than wet sites. The role of such refugia in recolonization, however, warrants further investigation.

  • 25.
    Hylander, Kristoffer
    et al.
    Stockholm University, Faculty of Science, Department of Botany. Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Nemomissa, Sileshi
    Home garden coffee as a repository of epiphyte biodiversity in Ethiopia2008In: Frontiers of Ecology and the Environment, Vol. 6, no 10, p. 524-528Article in journal (Refereed)
  • 26.
    Hylander, Kristoffer
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Nemomissa, Sileshi
    Waiving the extinction debt: Can shade from coffee prevent extinctions of epiphytic plants from isolated trees?2017In: Diversity & distributions: A journal of biological invasions and biodiversity, ISSN 1366-9516, E-ISSN 1472-4642, Vol. 23, no 8, p. 888-897Article in journal (Refereed)
    Abstract [en]

    AimLocal extinction after habitat modifications is often delayed, leading to an extinction debt. Our first aim was to develop a conceptual model for natural and human-mediated habitat improvements after a disturbance that may waive part of the predicted extinction debt. Second, we wanted to test this model on the distribution of epiphytic plants on trees that had been isolated in the agricultural matrix after forest clearing, around which coffee subsequently had been planted with a possible improvement of the microclimate. LocationBonga, Southern Nations, Nationalities and Peoples Region (SNNPR), Ethiopia. MethodsWe studied 50 trees that had been isolated for periods ranging from a few years to half a century after clearing. The trees were now located in the agricultural landscape at different distances from intact Afromontane forests. Fourteen trees in the forests were used as references. Each tree was inventoried for all vascular epiphytic plants, mosses and liverworts. ResultsTime since clearance had a direct negative effect on number of forest specialist species via delayed extinctions and the detected large extinction debt of both bryophytes and vascular plants continued to be paid over several decades. However, time since clearance had an indirect positive effect on number of forest indicator species via the reappearance of shade from coffee planted surrounding the trees, even if the waiving effect on the extinction debt was rather small. Additionally, trees at further distances from the forest edge had fewer forest-associated species. Main conclusionsOur results show that the ability of agroecological landscapes to foster forest biodiversity may be overestimated if meta-community processes over time and space are not taken into account. However, the possibility of initiating counteracting processes that modify the level of expected local extinctions should be evaluated more often to find ways of improving conditions for biodiversity in human-modified landscapes.

  • 27.
    Hylander, Kristoffer
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Nemomissa, Sileshi
    Delrue, Josefien
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Enkosa, Woldeyohannes
    Effects of Coffee Management on Deforestation Rates and Forest Integrity2013In: Conservation Biology, ISSN 0888-8892, E-ISSN 1523-1739, Vol. 27, no 5, p. 1031-1040Article in journal (Refereed)
    Abstract [en]

    Knowledge about how forest margins are utilized can be crucial for a general understanding of changes in forest cover, forest structure, and biodiversity across landscapes. We studied forest-agriculture transitions in southwestern Ethiopia and hypothesized that the presence of coffee (Coffea arabica)decreases deforestation rates because of coffee's importance to local economies and its widespread occurrence in forests and forest margins. Using satellite images and elevation data, we compared changes in forest cover over 37 years (1973-2010) across elevations in 2 forest-agriculture mosaic landscapes (1100 km(2) around Bonga and 3000 km(2) in Goma-Gera). In the field in the Bonga area, we determined coffee cover and forest structure in 40 forest margins that differed in time since deforestation. Both the absolute and relative deforestation rates were lower at coffee-growing elevations compared with at higher elevations (-10/20% vs. -40/50% comparing relative rates at 1800 m asl and 2300-2500 m asl, respectively). Within the coffee-growing elevation, the proportion of sites with high coffee cover (>20%) was significantly higher in stable margins (42% of sites that had been in the same location for the entire period) than in recently changed margins (0% of sites where expansion of annual crops had changed the margin). Disturbance level and forest structure did not differ between sites with 30% or 3% coffee. However, a growing body of literature on gradients of coffee management in Ethiopia reports coffee's negative effects on abundances of forest-specialist species. Even if the presence of coffee slows down the conversion of forest to annual-crop agriculture, there is a risk that an intensification of coffee management will still threaten forest biodiversity, including the genetic diversity of wild coffee. Conservation policy for Ethiopian forests thus needs to develop strategies that acknowledge that forests without coffee production may have higher deforestation risks than forests with coffee production and that forests with coffee production often have lower biodiversity value. Efectos de la Administracion Cafetalera sobre las Tasas de Deforestacion y la Integridad de los Bosques Resumen El conocimiento sobre como se utilizan los margenes de los bosques puede ser crucial para el entendimiento general de los cambios en la cubierta boscosa, la estructura de los bosques y la biodiversidad en el paisaje. Estudiamos transiciones bosque-agricultura en el suroeste de Etiopia y partimos de la hipotesis de que la presencia del cafe (Coffea arabica) disminuye las tasas de deforestacion por la importancia del cafe para las economias locales y su ocurrencia extensa en los bosques y los margenes de estos. Usando imagenes de satelite e informacion de elevacion, comparamos los cambios en la cubierta boscosa a traves de 37 anos (1973-2010) a lo largo de elevaciones en 2 paisajes mosaico de bosque y sembradios (1100 km(2) alrededor de Bonga y 3000 km(2) en Goma-Gera). En el campo en el area de Bonga determinamos la cobertura de cafe y la estructura del bosque en 40 margenes de bosque que difirieron en el tiempo desde la deforestacion. Tanto la tasa absoluta como la relativa de deforestacion fueron mas bajas en las elevaciones donde se cultiva cafe comparadas con las de elevaciones mas altas (-10/20% vs. -40/50% comparando tasas relativas en 1800 msnm y 2300-2500 msnm, respectivamente). Dentro de la elevacion donde se cultiva cafe, la proporcion de sitios con una alta cobertura de cafe (>20%) fue significativamente mas alta en los margenes estables (42% de los sitios que habian estado en la misma localidad durante el periodo entero) que en los margenes con cambios recientes (0% de los sitios donde la expansion anual de cultivos habian alterado el margen). El nivel de perturbacion y de estructura del bosque no difirio entre los sitios con 30% o 3% de cafe. Sin embargo, un creciente cuerpo de literatura sobre los gradientes de administracion del cafe en Etiopia reportan los efectos negativos del cafe sobre la abundancia de especies especialistas de bosques. Aunque sea cierto que la presencia de cafe disminuye la conversion de bosque a sembradios de cosecha anual, existe el riesgo de que la intensificacion de la administracion de cafe todavia amenace la biodiversidad del bosque, incluyendo la diversidad genetica del cafe silvestre. La politica de conservacion para los bosques etiopes entonces debe desarrollar estrategias que reconozcan que los bosques sin produccion cafetalera pueden tener riesgos mayores de deforestacion que los bosques con produccion cafetalera y que los bosques con produccion cafetalera seguido tienen un valor bajo de biodiversidad.

  • 28.
    Hylander, Kristoffer
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Nemomissa, Sileshi
    Hedenäs, Lars
    Mosses of southwest Ethiopian montane forests - notes on their occurrence pattern and many new country records2017In: Journal of Bryology, ISSN 0373-6687, E-ISSN 1743-2820, Vol. 39, no 4, p. 342-352Article in journal (Refereed)
    Abstract [en]

    One hundred and thirty-nine taxa of mosses are reported from the montane forest zone of southwest Ethiopia. Of these, 53 taxa are new country records and Meteoriopsis reclinata (Mull. Hal.) M. Fleisch. ex Broth. is, in addition, new to Africa. Most of the new records are of species also found in Uganda, Kenya or Tanzania, but there are some surprises, such as Fabronia perciliata Mull. Hal. with the closest location in South Africa and Namibia, Entodontella cameruniae Broth. previously known only from West Africa and Bryomaltaea obtusifolia (Hook.) Goffinet, otherwise reported only from the Democratic Republic of the Congo. We list all taxa and give a short account of their frequency and in which habitat and on which substrate they grow. That such a large proportion of the species are new to the country suggests that Ethiopia is bryologically very under-explored, and that further exploration will reveal many additional species. In particular, the remnant forests of southwest Ethiopia are likely to be of great importance as bryophyte hotspots.

  • 29.
    Hylander, Kristoffer
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Pocs, Tamas
    Nemomissa, Sileshi
    Liverworts of southwest Ethiopian montane forests: ecological and biogeographical notes2010In: Journal of Bryology, ISSN 0373-6687, E-ISSN 1743-2820, Vol. 32, p. 92-100Article in journal (Refereed)
    Abstract [en]

    Ethiopia has diverse topographic features and climatic conditions with a diverse flora. The liverwort flora of southwest Ethiopia is practically unknown, despite a favourable climate and the occurrence of suitable ecosystems such as montane rainforests. During an ecological study of diversity patterns of bryophytes and vascular plants in relation to land use, we recorded many bryophyte species. In this paper we report the finding of 89 species of liverworts, and give short ecological notes and describe the distribution (locally and in Africa) for each species. Of these, 51 species are newly reported from Ethiopia. It is thus obvious that Ethiopia is considerably richer in liverworts than might be expected from previous checklists.

  • 30.
    Hylander, Kristoffer
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Weibull, Henrik
    Do time-lagged extinctions and colonizations change the interpretation of buffer strip effectiveness?: a study of riparian bryophytes in the first decade after logging2012In: Journal of Applied Ecology, ISSN 0021-8901, E-ISSN 1365-2664, Vol. 49, no 6, p. 1316-1324Article in journal (Refereed)
    Abstract [en]

    There is a risk that short-term studies either underestimate disturbance effects because of time-lagged responses, including both time-lagged extinctions and colonizations, or overestimate them because of fast recovery. To evaluate the conservation effectiveness of tree group retention (in this case, buffer strips along streams), we studied the bryophyte community once prior to, and twice after logging, comparing one buffer and one clear-cut plot (0.1 ha) in each of 13 riparian sites. We asked whether time-lagged responses or recovery processes had dominated the period between two re-inventories, 2.5 and 10.5 years after logging, focusing both on the whole community and on species of conservation concern. Although there were examples of recovering species in both clear-cuts and buffer strips, the similarity in species composition to predisturbance conditions had decreased in the second re-inventory. Even if the buffer strips displayed more time-lagged colonizations and local extinctions over the later period compared to the clear-cuts, the overall species composition in the buffer strips was still significantly more similar to the prelogging conditions than the clear-cuts. The red-listed species had mostly declined during the first period, and the number of red-list species per plot (mostly species growing on dead wood) was rather stable at <20% of predisturbance levels in clear-cuts and <60% in buffer strips in the last re-inventory. Synthesis and applications. We show that most extinctions of red-list species occurred soon after disturbance and that the conclusions drawn from a study carried out 2.5 years after the disturbance did not change profoundly 8 years later. Although the species composition in the buffer strips continued to change over time, sensitive species survived much better in buffer strips than in clear-cuts, which supports the practice of retaining buffer strips for terrestrial species too. This knowledge should encourage managers to find ways of increasing the efficacy of this practice. One obvious measure could be to retain wider strips or implement other management practices that make the buffer strips less sensitive to wind, which will lead to higher tree retention to support a prelogging species composition.

  • 31. Jara, Taye
    et al.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Nemomissa, Sileshi
    Tree diversity across different tropical agricultural land use types2017In: Agriculture, Ecosystems & Environment, ISSN 0167-8809, E-ISSN 1873-2305, Vol. 240, p. 92-100Article in journal (Refereed)
    Abstract [en]

    A recent trend in conservation biology is not only to focus on protected areas of natural vegetation but also on the management of agricultural landscapes, since these landscapes are considered to be-of vital importance for overall landscape biodiversity both through the opportunity for species to thrive there and as conduits for inter-patch dispersal. Since trees are considered to be key structures to enhance biodiversity in agricultural landscapes, we need to understand what factors regulate their occurrences. Farmers choices will decide the composition of land-uses and the associated densities and composition of trees. We compared tree density and tree species composition across eight different land use types replicated in ten agricultural landscapes in relatively humid climates of mid-altitudes (1500-2500 m asl) in Ethiopia. In each landscape five transects of 1 km divided into 50 plots of 20 x 20 m were surveyed for woody plants. Annual crop plots had a low tree density (of trees >10 cm DBH) (6 per ha), but since it generally was the most abundant land use type altogether, many tree species were still found there (4-29 per transect in the different landscapes). Most tree species had their highest relative occurrence in the perenial crops land-use type and among the different perenial crop types, plots with coffee were more species rich than plots with khat (Catha edulis) (a stimulant crop increasing in frequency); plots with Eucalyptus trees were intermediate. A few species were more associated with grazing areas and homegardens indicating that a combination of land-uses enhances the overall species diversity in these agricultural landscapes. However, if the trend of increasing areas of khat and Eucalyptus would lead to decreases in shade coffee there is a risk for severe erosion of tree density and species richness across these landscapes with cascading effects on associated biodiversity.

  • 32.
    Johansson, Victor
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Swedish University of Agricultural Sciences, Sweden.
    Lönnell, Niklas
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Swedish University of Agricultural Sciences, Sweden.
    Rannik, Ullar
    Sundberg, Sebastian
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Air humidity thresholds trigger active moss spore release to extend dispersal in space and time2016In: Functional Ecology, ISSN 0269-8463, E-ISSN 1365-2435, Vol. 30, no 7, p. 1196-1204Article in journal (Refereed)
    Abstract [en]

    Understanding the complete dispersal process is important for making realistic predictions of species distributions, but mechanisms for diaspore release in wind-dispersed species are often unknown. However, diaspore release under conditions that increase the probability of longer dispersal distances and mechanisms that extend dispersal events in time may have evolutionary advantages. We quantified air humidity thresholds regulating spore release in the moss Brachythecium rutabulum. We also investigated the prevailing micrometeorological conditions when these thresholds occur in nature and how they affect dispersal distances up to 100m, using a mechanistic dispersal model. We show that moss spores were mainly released when the peristome teeth were opening, as relative air humidity (RH) decreased from high values to relatively low (mainly between 90% and 75% RH). This most often occurred in the morning, when wind speeds were relatively low. Surprisingly, the model predicted that an equally high proportion of the spores would travel distances beyond 100m (horizontally) when released in the wind conditions prevailing during events of RH decrease in the morning, that lead to peristome opening, as in the highest wind speeds. Moreover, a higher proportion of the spores reached high altitudes when released at the lower wind speeds during the morning compared to the higher speeds later in the day, indicating a possibility for extended dispersal distances when released in the morning. Dispersal in the morning is enhanced by a combination of a more unstable atmospheric surface layer that promotes vertical dispersal, and a lower wind speed that decreases the spore deposition probability onto the ground, compared to later in the day. Our study demonstrates an active spore release mechanism in response to diurnally changing air humidity. The mechanism may promote longer dispersal distances, because of enhanced vertical dispersal and because spores being released in the morning have more time to travel before the wind calms down at night. The mechanism also leads to a prolonged dispersal period over the season, which may be viewed as a risk spreading in time that ultimately also leads to a higher diversity of establishment conditions, dispersal distances and directions.

  • 33.
    Johansson, Victor
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Lönnell, Niklas
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Sundberg, Sebastian
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Release thresholds for moss spores: the importance of turbulence and sporophyte length2014In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 102, no 3, p. 721-729Article in journal (Refereed)
    Abstract [en]

    Adequately describing the dispersal mechanisms of a species is important for understanding and predicting its distribution dynamics in space and time. For wind-dispersed species, the transportation of airborne propagules is comparatively well studied, while the mechanisms triggering propagule release are poorly understood, especially for cryptogams. We investigated the effect of wind speed and turbulence on spore release in the moss Atrichum undulatum in a wind tunnel. Specifically, we measured the amount of spores released from sporophytes when exposed to different wind speeds, in high and low turbulence, using a particle counter. We also related spore release to variation in vibrations of the sporophyte and investigated how the vibrations were affected by wind speed, turbulence and sporophyte length (here including capsule, seta and the top part of the shoot). We show that in high turbulence, the amount of spores released increased with increasing wind speed, while in low turbulence, it did not, within the wind speed range 0.8-4.3ms(-1). However, there was a threshold in wind speed (similar to 2.5-3ms(-1)) before large amounts of spores started to be released in turbulent flow, which coincided with incipient vibrations of the sporophyte. Thresholds in wind variation, rather than average wind speed, seemed to initiate sporophyte vibrations. The vibration threshold increased with decreasing sporophyte length. The deposition of spores near the source decreased with increasing wind variation during the time of their release, based on simulated spore deposition from another study of moss dispersal. Synthesis. We suggest that vibration of moss sporophytes is an important mechanism to regulate spore release and that turbulence and sporophyte length regulate the onset of sporophyte vibration. Spore release thresholds affect dispersal distances and have implications for our understanding and predictions of species distribution patterns, population dynamics and persistence. The mechanisms of this phase of the dispersal process are also important to explore for other species, as there may be a substantial variation depending on the species' different traits.

  • 34. Juřičková, L.
    et al.
    Horsák, M
    Cameron, R.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Botany. Växtekologi.
    Míkovcová, A.
    Hlaváč, J.Č.
    Rohovec, J.
    Land snail distribution patterns within a site: the role of different calcium sources2008In: European Journal of Soil Biology, Vol. 44, p. 172-179Article in journal (Refereed)
  • 35. Lemessa, Debissa
    et al.
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Arthropod but Not Bird Predation in Ethiopian Homegardens Is Higher in Tree-Poor than in Tree-Rich Landscapes2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 5, article id e0126639Article in journal (Refereed)
    Abstract [en]

    Bird and arthropod predation is often associated with natural pest control in agricultural landscapes, but the rates of predation may vary with the amount of tree cover or other environmental factors. We examined bird and arthropod predation in three tree-rich and three tree-poor landscapes across southwestern Ethiopia. Within each landscape we selected three tree-rich and three tree-poor homegardens in which we recorded the number of tree species and tree stems within 100 x 100 m surrounding the central house. To estimate predation rates, we attached plasticine caterpillars on leaves of two coffee and two avocado shrubs in each homegarden, and recorded the number of attacked caterpillars for 7-9 consecutive weeks. The overall mean daily predation rate was 1.45% for birds and 1.60% for arthropods. The rates of arthropod predation varied among landscapes and were higher in tree-poor landscapes. There was no such difference for birds. Within landscapes, predation rates from birds and arthropods did not vary between tree-rich and tree-poor homegardens in either tree-rich or tree-poor landscapes. The most surprising result was the lack of response by birds to tree cover at either spatial scale. Our results suggest that in tree-poor landscapes there are still enough non-crop habitats to support predatory arthropods and birds to deliver strong top-down effect on crop pests.

  • 36.
    Lemessa, Debissa
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    The effect of local and landscape level land-use composition on predatory arthropods in a tropical agricultural landscape2015In: Landscape Ecology, ISSN 0921-2973, E-ISSN 1572-9761, Vol. 30, no 1, p. 167-180Article in journal (Refereed)
    Abstract [en]

    It has been suggested that the composition of different non-crop land-use types along with tree density regulate local biodiversity in agricultural landscapes. However, specific data is limited, not least from tropical regions. We examined how different land-use types and forest cover at different scales influenced the abundance and species composition of predatory arthropods in 40 homegardens of southwest Ethiopia. We collected specimens using pitfall traps during two separate months and related sample composition to land-use in the vicinity (1 ha plot, local scale, field data) and tree cover within 200 and 500 m radius zones (landscape scale, satellite data). Spiders, beetles and ants were most common. A high abundance of ants was found in tree-rich homegardens while the variation in abundance of spiders was best explained by the interaction between tree cover at the local and landscape scales. The highest spider abundances were found when either the homegarden or the surroundings had high tree-cover and was lower in both the most tree-rich and tree-poor landscape-garden combinations. In addition, open non-crop cover (mostly grasslands) and ensete (a banana-like perennial crop) favored spiders. This pattern demonstrates that different land-use types at different scales can interact to create variations in biodiversity across an agricultural landscape. To enhance numbers of predatory arthropods in homegardens, which may be beneficial for natural pest control, our results suggest that different strategies are needed depending on the target group or species. Grasslands, ensete fields and tree-rich habitats seem to play important roles.

  • 37.
    Lemessa, Debissa
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hambäck, Peter
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Birds and arthropod predation on plasticine caterpillars across tropical agricultural landscapesManuscript (preprint) (Other academic)
  • 38.
    Lemessa, Debissa
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hambäck, Peter
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Composition of crops and land-use types in relation to crop raiding pattern at different distances from forests2013In: Agriculture, Ecosystems & Environment, ISSN 0167-8809, E-ISSN 1873-2305, Vol. 167, p. 71-78Article in journal (Refereed)
    Abstract [en]

    Among the issues that farmers need to account for when planning their land-use and crop choice is yield loss from wild animals. The aim of this study was to examine both the distribution of land-use types and crops (in fields and homegardens) in relation to distance from forest edges and the possible impact of crop raiding mammals. Thirty transects of 1 km in length were laid out in a pair-wise design - 15 close to (<= 0.3 km) and 15 far from (1-3.5 km) forest edges. We measured the cover of the land-use types and field crops in each transect and assessed crop species composition in 4-6 homegardens along each transect. We also conducted a questionnaire survey for the occurrence of baboons and bush pigs in maize fields and in homegardens. Our results indicated that the distribution of land-use types and field crops was not significantly different between sites close to and far from forest edges. Similarly, the distributions of field and homegarden crop species composition were also similar between these locations. The occurrence pattern of baboons and bush pigs coming to the fields and homegardens was however strongly inclined toward transects close to forest edges according to the answers from the farmers. Although crops, such as maize, sorghum, tuber and root crops are frequently attacked by either baboons or pigs or both, farmers apparently did not stop growing these crops. The major reasons for this lack of response in growing practices between sites close to and far from forests could either be a perceived lack of alternative less susceptible crops or that farmers have adapted different protection mechanisms for the problem to be manageable. Both ecological and socio-economic studies are needed in order to understand the variation (and sometimes lack of variation) of ecosystem properties and corresponding management practices across landscapes.

  • 39. Lemessa, Debissa
    et al.
    Samnegård, Ulrika
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hambäck, Peter A.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Tree cover mediates the effect on rapeseed leaf damage of excluding predatory arthropods, but in an unexpected way2015In: Agriculture, Ecosystems & Environment, ISSN 0167-8809, E-ISSN 1873-2305, Vol. 211, p. 57-64Article in journal (Refereed)
    Abstract [en]

    Birds and predatory arthropods are often implicated in pest control, but their relative impact and how this is mediated by variation in tree cover requires elucidation. We excluded birds and ground predatory arthropods from rapeseed plants in 2.5 x 1 m plots in 26 homegardens in Ethiopia, leaving the same sized control plots. From six groups of plants in bird exclosure and control plots, respectively, three groups were excluded from ground predatory arthropods. Data on leaf damage were surveyed four times at weekly intervals. The tree cover and land-use composition within 100 x 100 m surrounding each plots were recorded in the field and from a satellite image within 200 and 500 m buffer zones. The results show that the mean leaf damage was higher on rapeseed plants from which predatory arthropods were excluded than on control plants. However, excluding birds had no or only a weak impact on leaf damage. The mean leaf damage within predatory arthropod exclosures decreased with increasing tree, forest and perennial cover but increased with increasing grazing land cover and annual crop cover, while on control plants it was low across the tree cover variation. This pattern may indicate the presence of a higher density of herbivores on rapeseed plants and also more predatory arthropods (i.e., to control them) in tree-poor homegardens compared to tree-rich homegardens. Hence, tree-poor homegardens in this landscape have sufficient habitat heterogeneity to support natural enemies to deliver significant pest control on rapeseed. Our results show that there was variation in the dynamics of pests and predatory arthropods across the tree cover variation, suggesting changes in landscape composition could affect the pest control services and the outcomes for local farmers.

  • 40. Lenoir, Jonathan
    et al.
    Graae, Bente Jessen
    Aarrestad, Per Arild
    Alsos, Inger Greve
    Armbruster, W. Scott
    Austrheim, Gunnar
    Bergendorff, Claes
    Birks, H. John B.
    Brathen, Kari Anne
    Brunet, Jorg
    Bruun, Hans Henrik
    Dahlberg, Carl Johan
    Stockholm University, Faculty of Science, Department of Botany.
    Decocq, Guillaume
    Diekmann, Martin
    Dynesius, Mats
    Ejrnaes, Rasmus
    Grytnes, John-Arvid
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Botany.
    Klanderud, Kari
    Luoto, Miska
    Milbau, Ann
    Moora, Mari
    Nygaard, Bettina
    Odland, Arvid
    Ravolainen, Virve Tuulia
    Reinhardt, Stefanie
    Sandvik, Sylvi Marlen
    Schei, Fride Hoistad
    Speed, James David Mervyn
    Tveraabak, Liv Unn
    Vandvik, Vigdis
    Velle, Liv Guri
    Virtanen, Risto
    Zobel, Martin
    Svenning, Jens-Christian
    Local temperatures inferred from plant communities suggest strong spatial buffering of climate warming across Northern Europe2013In: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 19, no 5, p. 1470-1481Article in journal (Refereed)
    Abstract [en]

    Recent studies from mountainous areas of small spatial extent (<2500km2) suggest that fine-grained thermal variability over tens or hundreds of metres exceeds much of the climate warming expected for the coming decades. Such variability in temperature provides buffering to mitigate climate-change impacts. Is this local spatial buffering restricted to topographically complex terrains? To answer this, we here study fine-grained thermal variability across a 2500-km wide latitudinal gradient in Northern Europe encompassing a large array of topographic complexities. We first combined plant community data, Ellenberg temperature indicator values, locally measured temperatures (LmT) and globally interpolated temperatures (GiT) in a modelling framework to infer biologically relevant temperature conditions from plant assemblages within <1000-m2 units (community-inferred temperatures: CiT). We then assessed: (1) CiT range (thermal variability) within 1-km2 units; (2) the relationship between CiT range and topographically and geographically derived predictors at 1-km resolution; and (3) whether spatial turnover in CiT is greater than spatial turnover in GiT within 100-km2 units. Ellenberg temperature indicator values in combination with plant assemblages explained 4672% of variation in LmT and 9296% of variation in GiT during the growing season (June, July, August). Growing-season CiT range within 1-km2 units peaked at 6065 degrees N and increased with terrain roughness, averaging 1.97 degrees C (SD=0.84 degrees C) and 2.68 degrees C (SD=1.26 degrees C) within the flattest and roughest units respectively. Complex interactions between topography-related variables and latitude explained 35% of variation in growing-season CiT range when accounting for sampling effort and residual spatial autocorrelation. Spatial turnover in growing-season CiT within 100-km2 units was, on average, 1.8 times greater (0.32 degrees Ckm1) than spatial turnover in growing-season GiT (0.18 degrees Ckm1). We conclude that thermal variability within 1-km2 units strongly increases local spatial buffering of future climate warming across Northern Europe, even in the flattest terrains.

  • 41.
    Lönnell, Niklas
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Calcicolous plants colonize limed mires after long-distance dispersal.Manuscript (preprint) (Other academic)
  • 42.
    Lönnell, Niklas
    et al.
    Stockholm University, Faculty of Science, Department of Botany.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Botany.
    Jonsson, Bengt Gunnar
    Sundberg, Sebastian
    The fate of the missing spores patterns of realized dispersal beyond the closest vicinity of a sporulating moss2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 7, p. e41987-Article in journal (Refereed)
    Abstract [en]

    It is well-known that many species with small diaspores can disperse far during extended temporal scales (many years). However, studies on short temporal scales usually only cover short distances (in, e.g., bryophytes up to 15 m). By using a novel experimental design, studying the realized dispersal, we extend this range by almost two orders of magnitude. We recorded establishment of the fast-growing moss Discelium nudum on introduced suitable substrates, placed around a translocated, sporulating mother colony. Around 2,000 pots with acidic clay were placed at different distances between 5 m and 600 m, in four directions, on a raised bog, with increased pot numbers with distance. The experiment was set up in April-May and the realized dispersal (number of colonized pots) was recorded in September. Close to the mother colony (up to 10 m), the mean colonization rates (ratio of colonized pots) exceeded 50%. At distances between 10 and 50 m colonization dropped sharply, but beyond 50 m the mean colonization rates stabilized and hardly changed (1-3%). The estimated density of spores causing establishments at the further distances (2-6 spores/m(2)) was realistic when compared to the estimated spore output from the central colonies. Our study supports calculations from earlier studies, limited to short distances, that a majority of the spores disperse beyond the nearest vicinity of a source. The even colonization pattern at further distances raises interesting questions about under what conditions spores are transported and deposited. However, it is clear that regular establishment is likely at the km-scale for this and many other species with similar spore output and dispersal mechanism.

  • 43.
    Lönnell, Niklas
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Jonsson, Bengt Gunnar
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Production of diaspores at the landscape level regulates local colonization: an experiment with a spore-dispersed moss2014In: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 37, no 6, p. 591-598Article in journal (Refereed)
    Abstract [en]

    Effective dispersal is crucial to species inhabiting transient substrates in order for them to be able to persist in a landscape. Bryophytes, pteridophytes, lichens and fungi all have wind-dispersed small diaspores and can be efficiently dispersed if their diaspores reach air masses above canopy height. However, empirical data on dispersal over landscape scales are scarce. We investigated how the colonization of an acrocarpous clay-inhabiting pioneer moss, Discelium nudum, varied between sites that differed in connectivity to potential dispersal sources at spatial scales from 1 to 20 km in a region in northern Sweden. We recorded the colonization on ˜25 introduced clay heaps at each of 14 experimental sites some months after the dispersal period. The colonization rate ranged from 0–82% and had a statistically significant relationship with a proxy for potential habitats (amount of clay-dominated soil) in a buffer of 20 km radius surrounding the experimental sites (and also weakly with the amount of substrate in a 10 km buffer). There were no significant relationships between colonization rate and connectivity at smaller scales (1 and 5 km). We made a rough estimate of the number of spores available for dispersal in a landscape, given the amount of clay-dominated soil, by recording the number of Discelium nudum colonies in two 25 × 25 km landscapes. The estimated available spore numbers in the different 20 km buffers were of the same order of magnitude as the deposition densities at the experimental sites calculated from the colonization rates. The results suggest that the spores of species with scattered occurrences and small diaspores (25 μm) in open landscapes can be deposited over extensive areas, at rates high enough to drive colonization patterns. This also implies that regional connectivity may be more important than local connectivity for these kinds of species.

  • 44. Lönnell, Niklas
    et al.
    Norros, Veera
    Sundberg, Sebastian
    Rannik, Üllar
    Johansson, Victor
    Ovaskainen, Otso
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Testing a mechanistic dispersal model against a dispersal experiment with a wind-dispersed moss2015In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 124, no 9, p. 1232-1240Article in journal (Refereed)
    Abstract [en]

    Wind is the main dispersal agent for a wide array of species and for these species the environmental conditions under which diaspores are released can potentially modify the dispersal kernel substantially. Little is known about how bryophytes regulate spore release, but conditions affecting peristome movements and vibration of the seta may be important. We modelled airborne spore dispersal of the bryophyte species Discelium nudum (spore diameter 25 m), in four different release scenarios, using a Lagrangian stochastic dispersion model and meteorological data. We tested the model predictions against experimental data on colonization success at five distances (5, 10, 30, 50 and 100 m) and eight directions from a translocated point source during seven two-day periods. The model predictions were generally successful in describing the observed colonization patterns, especially beyond 10 m. In the laboratory we established spore release thresholds; horizontal wind speed sd > 0.25 m s(-1) induced the seta to vibrate and in relative humidity < 75% the peristome was open. Our dispersal model predicts that the proportion of spores dispersing beyond 100 m is almost twice as large if the spores are released under turbulent conditions than under more stable conditions. However, including release thresholds improved the fit of the model to the colonization data only minimally, with roughly the same amount of variation explained by the most constrained scenario (assuming both vibration of the seta and an open peristome) and the scenario assuming random release. Model predictions under realised experimental conditions suggest that we had a low statistical power to rank the release scenarios due to the lack of measurements of the absolute rate of spore release. Our results hint at the importance of release conditions, but also highlight the challenges in dispersal experiments intended for validating mechanistic dispersal models.

  • 45.
    Lönnell, Niklas
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Sundberg, Sebastian
    Norros, Veera
    Rannik, Üllar
    Johansson, Victor
    Ovaskainen, Otso
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Colonization patterns of a wind-dispersed moss in relation to modelled dispersal based on meteorological data.Manuscript (preprint) (Other academic)
  • 46. Medina, Rafael
    et al.
    Yang, Liu
    Wang, Li-Song
    Guo, Shuiliang
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Botany.
    Goffinet, Bernard
    DNA based revised geographic circumscription of species of Physcomitrella s.l. (Funariaceae): P. patens new to East Asia and P. magdalenae new to East Africa2015In: The Bryologist, ISSN 0007-2745, E-ISSN 1938-4378, Vol. 118, no 1, p. 22-31Article in journal (Refereed)
    Abstract [en]

    Physcomitrella, as traditionally defined, accommodates certain Funariaceae with immersed and cleistocarpous capsules. Recent molecular inferences revealed that the three or four taxa typically recognized within Physcomitrella did not arise from a unique common ancestor, and hence that their morphological similarities likely resulted from convergence, while one potential taxon, P. patens subsp. californica (=Physcomitridium readeri s.l.), is currently regarded as a polyphyletic entity, making Physcomitridium polyphyletic. Following recent discoveries that would greatly expand the known range of two taxa, we sampled populations of Physcomitrella s.l. from all main geographic regions, and sequenced the nuclear ITS regions and four plastid loci to assess the geographic circumscription of each clade. We recovered three unambiguous monophyletic entities matching the three morphotypes recognized by Fife, each with a distinct geographic range: Physcomitrella patens s.str. with a range in Europe and North America extended to East Asia (China); P. magdalenae with a range from West and Central Africa extended eastwards to Ethiopia; and Physcomitridium (Physcomitrella) readeri from western Europe and western North America to Japan and Australia, plus a doubtful occurrence in China. Although the distinction of P. californica from P. readeri remains doubtful, we reject the hypothesis that Physcomitridium is polyphyletic, arguing that this resulted from a misidentification of the sequenced voucher.

  • 47.
    Meineri, Eric
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Dahlberg, C. Johan
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Using Gaussian Bayesian Networks to disentangle direct and indirect associations between landscape physiography, environmental variables and species distribution2015In: Ecological Modelling, ISSN 0304-3800, E-ISSN 1872-7026, Vol. 313, p. 127-136Article in journal (Refereed)
    Abstract [en]

    Landscape physiography affects temperature, soil moisture and solar radiation. In turn, these variables are thought to determine how species are distributed across landscapes. Systems involving direct and indirect associations between variables can be described using path models. However, studies applying these to species distribution modelling are rare. Bayesian Networks are path models designed to represent associations across observed variables. Here, we demonstrate the use of Bayesian Networks to disentangle the direct and indirect associations between landscape physiography, soil moisture, solar radiation, temperature and the distribution patterns of four plants at their northern range limit in Sweden. Fine scale variations in maximum temperatures were associated with variations in elevation, distance to coast and solar radiation. In contrast, fine scale variations in minimum temperature were associated with distance to coast, cold air drainage and soil moisture. These associations between landscape physiography and minimum and maximum temperature were predicted, furthermore, to be associated with growing season length, growing degree day and ultimately species distributions. All species were indirectly associated with aspect through their responses to either solar radiation or temperature. The models demonstrated strong indirect associations between landscape physiography and species distributions. The models suggested that local variation in light can be as important as temperature for species distributions. Disentangling the direct and indirect associations between landscape physiography, environmental variables and species distribution can provide new and important insights into how landscape components are linked to species distributions.

  • 48.
    Meineri, Eric
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Fine-grain, large-domain climate models based on climate station and comprehensive topographic information improve microrefugia detection2017In: Ecography, ISSN 0906-7590, E-ISSN 1600-0587, Vol. 40, no 8, p. 1003-1013Article in journal (Refereed)
    Abstract [en]

    Large-domain species distribution models (SDMs) fail to identify microrefugia, as they are based on climate estimates that are either too coarse or that ignore relevant topographic climate-forcing factors. Climate station data are considered inadequate to produce such estimates, a viewpoint we challenge here. Using climate stations and topographic data, we developed three sets of large-domain (450 000 km(2)), fine-grain (50m) temperature grids accounting for different levels of topographic complexity. Using these fine-grain grids and the Worldclim data, we fitted SDMs for 78 alpine species over Sweden, and assessed over-versus underestimations of local extinction and area of microrefugia by comparing modelled distributions at species' rear edges. Accounting for well-known topographic climate-forcing factors improved our ability to model fine-scale climate, despite using only climate station data. This approach captured the effect of cool air pooling, distance to sea, and relative humidity on local-scale temperature, but the effect of solar radiation could not be accurately accounted for. Predicted extinction rate decreased with increasing spatial resolution of the climate models and with increasing number of topographic climate-forcing factors accounted for. About half of the microrefugia detected in the most topographically complete models were not detected in the coarser SDMs and in the models calibrated from climate variables extracted from elevation only. Although major limitations remain, climate station data can potentially be used to produce fine-grain topoclimate grids, opening up the opportunity to model local-scale ecological processes over large domains. Accounting for the topographic complexity encountered within landscapes permits the detection of microrefugia that would otherwise remain undetected. Topographic heterogeneity is likely to have a massive impact on species persistence, and should be included in studies on the effects of climate change.

  • 49.
    Moor, Helen
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Norberg, Jon
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Predicting climate change effects on wetland ecosystem services using species distribution modeling and plant functional traits2015In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, p. 113-126Article in journal (Refereed)
    Abstract [en]

    Wetlands provide multiple ecosystem services, the sustainable use of which requires knowledge of the underlying ecological mechanisms. Functional traits, particularly the community-weighted mean trait (CWMT), provide a strong link between species communities and ecosystem functioning. We here combine species distribution modeling and plant functional traits to estimate the direction of change of ecosystem processes under climate change. We model changes in CWMT values for traits relevant to three key services, focusing on the regional species pool in the Norrstrom area (central Sweden) and three main wetland types. Our method predicts proportional shifts toward faster growing, more productive and taller species, which tend to increase CWMT values of specific leaf area and canopy height, whereas changes in root depth vary. The predicted changes in CWMT values suggest a potential increase in flood attenuation services, a potential increase in short (but not long)-term nutrient retention, and ambiguous outcomes for carbon sequestration.

  • 50.
    Moor, Helen
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Rydin, Håkan
    Hylander, Kristoffer
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Nilsson, Mats B.
    Lindborg, Regina
    Stockholm University, Faculty of Science, Department of Physical Geography.
    Norberg, Jon
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Towards a trait-based ecology of wetland vegetation2017In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 105, no 6, p. 1623-1635Article, review/survey (Refereed)
    Abstract [en]

    1. Functional traits mechanistically capture plant responses to environmental gradients as well as plant effects on ecosystem functioning. Yet most trait-based theory stems from terrestrial systems and extension to other habitats can provide new insights. 2. Wetlands differ from terrestrial systems in conditions (e.g. soil water saturation, anoxia, pH extremes), plant adaptations (e.g. aerenchyma, clonality, ubiquity of bryophytes) and important processes (e.g. denitrification, peat accumulation, methane emission). Wetland plant adaptations and trait (co-)variation can be situated along major plant trait trade-off axes (e.g. the resource economics spectrum), but soil saturation represents a complex stress gradient beyond a simple extension of commonly studied water availability gradients. 3. Traits that affect ecosystem functioning overlap with patterns in terrestrial systems. But wetland-specific traits that mediate plant effects on soil redox conditions, microbial communities and on water flow, as well as trait spectra of mosses, vary among wetland types. 4. Synthesis. With increasing availability of quantitative plant traits a trait-based ecology of wetlands is emerging, with the potential to advance process-based understanding and prediction. We provide an interactive cause-and-effect framework that may guide research efforts to disentangle the multiple interacting processes involved in scaling from environmental conditions to ecosystem functioning via plant communities.

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