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  • 1.
    Aalberg Haugen, Inger M.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Berger, David
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen. Uppsala University, Sweden.
    Gotthard, Karl
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    The evolution of alternative developmental pathways: footprints of selection on life-history traits in a butterfly2012Inngår i: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 25, nr 7, s. 1377-1388Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Developmental pathways may evolve to optimize alternative phenotypes across environments. However, the maintenance of such adaptive plasticity under relaxed selection has received little study. We compare the expression of life-history traits across two developmental pathways in two populations of the butterfly Pararge aegeria where both populations express a diapause pathway but one never expresses direct development in nature. In the population with ongoing selection on both pathways, the difference between pathways in development time and growth rate was larger, whereas the difference in body size was smaller compared with the population experiencing relaxed selection on one pathway. This indicates that relaxed selection on the direct pathway has allowed life-history traits to drift towards values associated with lower fitness when following this pathway. Relaxed selection on direct development was also associated with a higher degree of genetic variation for protandry expressed as within-family sexual dimorphism in growth rate. Genetic correlations for larval growth rate across sexes and pathways were generally positive, with the notable exception of correlation estimates that involved directly developing males of the population that experienced relaxed selection on this pathway. We conclude that relaxed selection on one developmental pathway appears to have partly disrupted the developmental regulation of life-history trait expression. This in turn suggests that ongoing selection may be responsible for maintaining adaptive developmental regulation along alternative developmental pathways in these populations.

  • 2.
    Abbasi, Saeed
    et al.
    KTH Royal Inst Technol, Dept Machine Design, Stockholm, Sweden.
    Jansson, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Sellgren, Ulf
    KTH Royal Inst Technol, Dept Machine Design, Stockholm, Sweden.
    Olofsson, Ulf
    KTH Royal Inst Technol, Dept Machine Design, Stockholm, Sweden.
    Particle Emissions From Rail Traffic: A Literature Review2013Inngår i: Critical reviews in environmental science and technology, ISSN 1064-3389, E-ISSN 1547-6537, Vol. 43, nr 23, s. 2511-2544Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Particle emissions are a drawback of rail transport. This work is a comprehensive presentation of recent research into particle emissions from rail vehicles. Both exhaust and nonexhaust particle emissions are considered when examining particle characteristics such as PM10, and PM2.5 concentration levels, size, morphology, composition, and adverse health effects, current legislation, and available and proposed solutions for reducing such emissions. High concentration levels in enclosed rail traffic environments are reported and some toxic effects of the particles. The authors find that only a few limited studies have examined the adverse health effects of nonexhaust particle emissions and that no relevant legislation exists. Thus further research in this area is warranted.

  • 3. Abunge, Caroline
    et al.
    Coulthard, Sarah
    Daw, Tim M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Connecting Marine Ecosystem Services to Human Well-being: Insights from Participatory Well-being Assessment in Kenya2013Inngår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 42, nr 8, s. 1010-1021Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The linkage between ecosystems and human well-being is a focus of the conceptualization of ecosystem services as promoted by the Millennium Ecosystem Assessment. However, the actual nature of connections between ecosystems and the well-being of individuals remains complex and poorly understood. We conducted a series of qualitative focus groups with five different stakeholder groups connected to a small-scale Kenyan coastal fishery to understand (1) how well-being is understood within the community, and what is important for well-being, (2) how people's well-being has been affected by changes over the recent past, and (3) people's hopes and aspirations for their future fishery. Our results show that people conceive well-being in a diversity of ways, but that these can clearly map onto the MA framework. In particular, our research unpacks the freedoms and choices element of the framework and argues for greater recognition of these aspects of well-being in fisheries management in Kenya through, for example, more participatory governance processes.

  • 4.
    Ackefors, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Global fisheries - threats and opportunities2009Inngår i: Fisheries, sustainablity and development: fifty-two authors on coexistence and development of fisheries and aquaculture in developing and developed countries / [ed] Per Wramner, Hans Ackefors et al, Stockholm: Kungl. Skogs- och lantbruksakademien , 2009, s. 35-68-Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 5.
    Ackefors, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Är det politikerna eller fiskenäringen som styr fisket?2008Inngår i: Kungl. Skogs- och Lantbruksakademiens Tidskrift, ISSN 0023-5350, Vol. 147, nr 2, s. 36-43Artikkel i tidsskrift (Annet (populærvitenskap, debatt, mm))
  • 6.
    Aeppli, Christoph
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Bastviken, David
    Andersson, Per
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Chlorine Isotope Effects and Composition of Naturally Produced Organochlorines from Chloroperoxidases, Flavin-Dependent Halogenases, and in Forest Soil2013Inngår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 47, nr 13, s. 6864-6871Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The use of stable chlorine isotopic signatures (delta Cl-37) of organochlorine compounds has been suggested as a tool to determine both their origins and transformations in the environment. Here we investigated the delta Cl-37 fractionation of two important pathways for enzymatic natural halogenation: chlorination by chloroperoxidase (CPO) and flavin-dependent halogenases (FDH). Phenolic products of CPO were highly Cl-37 depleted (delta Cl-37 = -12.6 +/- 0.9 parts per thousand); significantly more depleted than all known industrially produced organochlorine compounds (delta Cl-37 = -7 to +6 parts per thousand). In contrast, four FDH products did not exhibit any observable isotopic shifts (delta Cl-37 = -0.3 +/- 0.6 parts per thousand). We attributed the different isotopic effect to the distinctly different chlorination mechanisms employed by the two enzymes. Furthermore, the delta Cl-37 in bulk organochlorines extracted from boreal forest soils were only slightly depleted in Cl-37 relative to inorganic Cl. In contrast to previous suggestions that CPO plays a key role in production of soil organochlorines, this observation points to the additional involvement of either other chlorination pathways, or that dechlorination of naturally produced organochlorines can neutralize delta Cl-37 shifts caused by CPO chlorination. Overall, this study demonstrates that chlorine isotopic signatures are highly useful to understand sources and cycling of organochlorines in nature. Furthermore, this study presents delta Cl-37 values of FDH products as well of bulk organochlorines extracted from pristine forest soil for the first time.

  • 7.
    Aeppli, Christoph
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Tysklind, Mats
    Holmstrand, Henry
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Use of Cl and C Isotopic Fractionation to Identify Degradation and Sources of Polychlorinated Phenols: Mechanistic Study and Field Application2013Inngår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 47, nr 2, s. 790-797Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The widespread use of chlorinated phenols (CPs) as a wood preservative has led to numerous contaminated sawmill sites. However, it remains challenging to assess the extent of in situ degradation of CPs. We evaluated the use of compound-specific chlorine and carbon isotope analysis (Cl- and C-CSLA) to assess CP biotransformation. In a laboratory system, we measured isotopic fractionation during oxidative 2,4,6-trichlorophenol dechlorination by representative soil enzymes (C. fumago chloroperoxidase, horseradish peroxidase, and laccase from T. versicolor). Using a mathematical model, the validity of the Rayleigh approach to evaluate apparent kinetic isotope effects (AKIE) was confirmed. A small but significant Cl-AKIE of 1.0022 +/- 0.0006 was observed for all three enzymes, consistent with a reaction pathway via a cationic radical species. For carbon, a slight inverse isotope effect was observed (C-AKIE = 0.9945 +/- 0.0019). This fractionation behavior is clearly distinguishable from reported reductive dechlorination mechanisms. Based on these results we then assessed degradation and apportioned different types of technical CP mixtures used at two former sawmill sites. To our knowledge, this is the first study that makes use of two-element CSIA to study sources and transformation of CPs in the environment.

  • 8.
    Ahlbeck, Ida
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Living in a predation matrix: Studies on fish and their prey in a Baltic Sea coastal area2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis was written within the framework of a biomanipulation project where young-of-the-year (YOY) pikeperch (Sander lucioperca) were stocked to a Baltic Sea bay to improve water quality through a top-down trophic cascade. The aim of my doctorial studies was however focused on a broader ecological question, namely predation (the main driving force in a biomanipulation). Hence, this thesis consists of four papers where we study the interactions between predator and prey using fish and zooplankton and how these interactions can be measured.

    In paper I we evaluated the performance of different diet analysis methods by individual based modelling and found that when having a nutritional gain perspective, mass based methods described diets best. Paper II investigated how the explorative, foraging and anti-predator behaviour of the YOY pikeperch used for stocking were affected by their rearing environment (pond vs. tank rearing). The more complex and varied environment in the semi-natural ponds seemed to promote a more flexible and active behaviour, better equipping young fish for survival in the wild. For paper III we studied the diel vertical migration in the six copepodite stages of the zooplankton Acartia spp. and Eurytemora affinis in relation to fish biomass, phytoplankton abundance and temperature. Both species migrated and in addition showed increased migration range with size within species, indicating evasion from visual predators. Paper IV addressed the movement of littoral Eurasian perch (Perca fluviatilis) via stable isotope signatures (13C and 15N) and body condition. We found clear indications of sedentarity and intra-habitat dietary differences. Interactions between predators and prey are complex and affected by both physiological and environmental characteristics as well as behavioural traits. The results in this thesis suggest that different species and even different life stages pursue different strategies to survive.

  • 9.
    Ahlbeck, Ida
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Hansson, Sture
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Hjerne, Olle
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Evaluation of diet analysis methods by individual based modellingInngår i: Canadian Journal of Fisheries and Aquatic Sciences, ISSN 0706-652X, E-ISSN 1205-7533Artikkel i tidsskrift (Fagfellevurdert)
  • 10.
    Ahlbeck, Ida
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Hansson, Sture
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Karlöf, Oliver
    Sedentarity in Eurasian perch (Perca fluviatilis) in a coastal Baltic Sea areaInngår i: Ecology of Freshwater Fish, ISSN 0906-6691, E-ISSN 1600-0633Artikkel i tidsskrift (Fagfellevurdert)
  • 11.
    Ahlbeck, Ida
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Holliland, Per B.
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Rearing environment affect important life skills in pikeperch (Sander lucioperca)2012Inngår i: Boreal environment research, ISSN 1239-6095, E-ISSN 1797-2469, Vol. 17, nr 3-4, s. 291-304Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The effect of rearing environment on the behaviour of young-of-the-year pikeperch (Sander lucioperca) bred at three different production facilities was investigated. Two groups were reared in semi-natural ponds and one group in indoor tanks. Exploratory, foraging and anti-predator behaviours were studied in aquarium experiments. There were no significant differences between pond- and tank-reared fish in reluctance to explore their new environment, but pond-reared fish spent significantly more time in macro-vegetation. Pond-reared fish were significantly faster to start foraging on live prey (Neomysis integer) that they had not encountered before. As compared with tank-reared fish, pond-reared fish were also significantly more active in their anti-predator response. Rearing environment obviously influences the development of important life skills. These differences may impact the success rate when stocking young-of-the-year pikeperch into natural waters.

  • 12. Ahmed, S.E.
    et al.
    Lees, A.C.
    Moura, N.G.
    Gardner, Toby A.
    Stockholms universitet, Stockholm Environment Institute.
    Road networks predict human influence on Amazonian bird communities2014Inngår i: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 281, nr 1795Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Road building can lead to significant deleterious impacts on biodiversity, varying from direct road-kill mortality and direct habitat loss associated with road construction, to more subtle indirect impacts from edge effects and fragmentation. However, little work has been done to evaluate the specific effects of road networks and biodiversity loss beyond the more generalized effects of habitat loss. Here, we compared forest bird species richness and composition in the municipalities of Santarém and Belterra in Pará state, eastern Brazilian Amazon, with a road network metric called ‘roadless volume (RV)’ at the scale of small hydrological catchments (averaging 3721 ha). We found a significant positive relationship between RV and both forest bird richness and the average number of unique species (species represented by a single record) recorded at each site. Forest bird community composition was also significantly affected by RV. Moreover, there was no significant correlation between RV and forest cover, suggesting that road networks may impact biodiversity independently of changes in forest cover. However, variance partitioning analysis indicated that RV has partially independent and therefore additive effects, suggesting that RV and forest cover are best used in a complementary manner to investigate changes in biodiversity. Road impacts on avian species richness and composition independent of habitat loss may result from road-dependent habitat disturbance and fragmentation effects that are not captured by total percentage habitat cover, such as selective logging, fire, hunting, traffic disturbance, edge effects and road-induced fragmentation

  • 13.
    Ahrné, Karin
    et al.
    Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Bengtsson, Jan
    Department of Ecology, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Elmqvist, Thomas
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Bumble Bees (Bombus spp) along a Gradient of Increasing Urbanization2009Inngår i: PLoS ONE, Vol. 4, nr 5Artikkel i tidsskrift (Fagfellevurdert)
  • 14.
    al Rawaf, Rawaf
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Social-Ecological Urbanism: Lessons in Design from the Albano Resilient Campus2017Independent thesis Advanced level (degree of Master (Two Years)), 80 poäng / 120 hpOppgave
    Abstract [en]

    Currently there is a demand for practical ways to integrate ecological insights into practices of design, which previously have lacked a substantive empirical basis. In the process of developing the Albano Resilient Campus, a transdisciplinary group of ecologists, design scholars, and architects pioneered a conceptual innovation, and a new paradigm of urban sustainability and development: Social-Ecological Urbanism.  Social-Ecological Urbanism is based on the frameworks of Ecosystem Services and Resilience thinking. This approach has created novel ideas with interesting repercussions for the international debate on sustainable urban development. From a discourse point of view, the concept of SEU can be seen as a next evolutionary step for sustainable urbanism paradigms, since it develops synergies between ecological and socio-technical systems. This case study collects ‘best practices’ that can lay a foundational platform for learning, innovation, partnership and trust building within the field of urban sustainability. It also bridges gaps in existing design approaches, such as Projective Ecologies and Design Thinking, with respect to a design methodology with its basis firmly rooted in Ecology.

  • 15. Alexandre, Ana
    et al.
    Silva, Joao
    Buapet, Pimchanok
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen.
    Björk, Mats
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen.
    Santos, Rui
    Effects of CO2 enrichment on photosynthesis, growth, and nitrogen metabolism of the seagrass Zostera noltii2012Inngår i: Ecology and Evolution, ISSN 2045-7758, Vol. 2, nr 10, s. 2620-2630Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Seagrass ecosystems are expected to benefit from the global increase in CO2 in the ocean because the photosynthetic rate of these plants may be C-i-limited at the current CO2 level. As well, it is expected that lower external pH will facilitate the nitrate uptake of seagrasses if nitrate is cotransported with H+ across the membrane as in terrestrial plants. Here, we investigate the effects of CO2 enrichment on both carbon and nitrogen metabolism of the seagrass Zostera noltii in a mesocosm experiment where plants were exposed for 5 months to two experimental CO2 concentrations (360 and 700 ppm). Both the maximum photosynthetic rate (Pm) and photosynthetic efficiency (alpha) were higher (1.3- and 4.1-fold, respectively) in plants exposed to CO2-enriched conditions. On the other hand, no significant effects of CO2 enrichment on leaf growth rates were observed, probably due to nitrogen limitation as revealed by the low nitrogen content of leaves. The leaf ammonium uptake rate and glutamine synthetase activity were not significantly affected by increased CO2 concentrations. On the other hand, the leaf nitrate uptake rate of plants exposed to CO2-enriched conditions was fourfold lower than the uptake of plants exposed to current CO2 level, suggesting that in the seagrass Z. noltii nitrate is not cotransported with H+ as in terrestrial plants. In contrast, the activity of nitrate reductase was threefold higher in plant leaves grown at high-CO2 concentrations. Our results suggest that the global effects of CO2 on seagrass production may be spatially heterogeneous and depend on the specific nitrogen availability of each system. Under a CO2 increase scenario, the natural levels of nutrients will probably become limiting for Z. noltii. This potential limitation becomes more relevant because the expected positive effect of CO2 increase on nitrate uptake rate was not confirmed.

  • 16. Allan, Ian J.
    et al.
    Nilsson, Hans C.
    Tjensvoll, Ingrid
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Bradshaw, Clare
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Naes, Kristoffer
    PCDD/F release during benthic trawler-induced sediment resuspension2012Inngår i: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 31, nr 12, s. 2780-2787Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Benthic trawling can cause the resuspension of large amounts of sediments. Such regular practice in the Grenland fjord system in the south of Norway has the potential to affect the fate, movement, and bioavailability of sediment-associated polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). A novel mode of exposing passive sampling devices consisting of towing semipermeable membrane devices attached to the trawl net was used to gauge in situ changes in the freely dissolved concentration of PCDD/Fs on benthic trawlerinduced sediment resuspension. Significant accumulation of a number of PCDD/F congeners was observed despite the short (5?h) sampler exposure times. On average, a one order of magnitude increase in freely dissolved PCCD/F concentrations was seen within minutes of the sediment being resuspended. This observation was supported by similar changes in filtered PCDD/F concentrations measured by high-volume sampling prior to resuspension and in the sediment plume. Environ. Toxicol. Chem. 2012; 31: 27802787.

  • 17. Allen, Craig R.
    et al.
    Angeler, David G.
    Cumming, Graeme S.
    Folke, Carl
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre. Royal Swedish Academy of Sciences, Sweden.
    Twidwell, Dirac
    Uden, Daniel R.
    Quantifying spatial resilience2016Inngår i: Journal of Applied Ecology, ISSN 0021-8901, E-ISSN 1365-2664, Vol. 53, nr 3, s. 625-635Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    1. Anthropogenic stressors affect the ecosystems upon which humanity relies. In some cases when resilience is exceeded, relatively small linear changes in stressors can cause relatively abrupt and nonlinear changes in ecosystems. 2. Ecological regime shifts occur when resilience is exceeded and ecosystems enter a new local equilibrium that differs in its structure and function from the previous state. Ecological resilience, the amount of disturbance that a system can withstand before it shifts into an alternative stability domain, is an important framework for understanding and managing ecological systems subject to collapse and reorganization. 3. Recently, interest in the influence of spatial characteristics of landscapes on resilience has increased. Understanding how spatial structure and variation in relevant variables in landscapes affects resilience to disturbance will assist with resilience quantification, and with local and regional management. 4. Synthesis and applications. We review the history and current status of spatial resilience in the research literature, expand upon existing literature to develop a more operational definition of spatial resilience, introduce additional elements of a spatial analytical approach to understanding resilience, present a framework for resilience operationalization and provide an overview of critical knowledge and technology gaps that should be addressed for the advancement of spatial resilience theory and its applications to management and conservation.

  • 18. Allen, Lisa Zeigler
    et al.
    McCrow, John P.
    Ininbergs, Karolina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik. Stockholms universitet, Science for Life Laboratory (SciLifeLab).
    Dupont, Christopher L.
    Badger, Jonathan H.
    Hoffman, Jeffery M.
    Ekman, Martin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik. Stockholms universitet, Science for Life Laboratory (SciLifeLab).
    Allen, Andrew E.
    Bergman, Birgitta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik. Stockholms universitet, Science for Life Laboratory (SciLifeLab).
    Venter, J. Craig
    The Baltic Sea Virome: Diversity and Transcriptional Activity of DNA and RNA Viruses2017Inngår i: mSystems, ISSN 2379-5077, Vol. 2, nr 1, artikkel-id UNSP e00125-16Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Metagenomic and metatranscriptomic data were generated from size-fractionated samples from 11 sites within the Baltic Sea and adjacent marine waters of Kattegat and freshwater Lake Tornetrask in order to investigate the diversity, distribution, and transcriptional activity of virioplankton. Such a transect, spanning a salinity gradient from freshwater to the open sea, facilitated a broad genome-enabled investigation of natural as well as impacted aspects of Baltic Sea viral communities. Taxonomic signatures representative of phages within the widely distributed order Caudovirales were identified with enrichments in lesser-known families such as Podoviridae and Siphoviridae. The distribution of phage reported to infect diverse and ubiquitous heterotrophic bacteria (SAR11 clades) and cyanobacteria (Synechococcus sp.) displayed population-level shifts in diversity. Samples from higher-salinity conditions (>14 practical salinity units [PSU]) had increased abundances of viruses for picoeukaryotes, i.e., Ostreococcus. These data, combined with host diversity estimates, suggest viral modulation of diversity on the whole-community scale, as well as in specific prokaryotic and eukaryotic lineages. RNA libraries revealed single-stranded DNA (ssDNA) and RNA viral populations throughout the Baltic Sea, with ssDNA phage highly represented in Lake Tornetrask. Further, our data suggest relatively high transcriptional activity of fish viruses within diverse families known to have broad host ranges, such as Nodoviridae (RNA), Iridoviridae (DNA), and predicted zoonotic viruses that can cause ecological and economic damage as well as impact human health. IMPORTANCE Inferred virus-host relationships, community structures of ubiquitous ecologically relevant groups, and identification of transcriptionally active populations have been achieved with our Baltic Sea study. Further, these data, highlighting the transcriptional activity of viruses, represent one of the more powerful uses of omics concerning ecosystem health. The use of omics-related data to assess ecosystem health holds great promise for rapid and relatively inexpensive determination of perturbations and risk, explicitly with regard to viral assemblages, as no single marker gene is suitable for widespread taxonomic coverage.

  • 19. Allendorf, Fred W.
    et al.
    Berry, Oliver
    Ryman, Nils
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    So long to genetic diversity, and thanks for all the fish2014Inngår i: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 23, nr 1, s. 23-25Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The world faces a global fishing crisis. Wild marine fisheries comprise nearly 15% of all animal protein in the human diet, but, according to the U.N. Food and Agriculture Organization, nearly 60% of all commercially important marine fish stocks are overexploited, recovering, or depleted (FAO 2012; Fig. 1). Some authors have suggested that the large population sizes of harvested marine fish make even collapsed populations resistant to the loss of genetic variation by genetic drift (e. g. Beverton 1990). In contrast, others have argued that the loss of alleles because of overfishing may actually be more dramatic in large populations than in small ones (Ryman et al. 1995). In this issue, Pinsky & Palumbi (2014) report that overfished populations have approximately 2% lower heterozygosity and 12% lower allelic richness than populations that are not overfished. They also performed simulations which suggest that their estimates likely underestimate the actual loss of rare alleles by a factor of three or four. This important paper shows that the harvesting of marine fish can have genetic effects that threaten the long-term sustainability of this valuable resource.

  • 20.
    Alm Bergvall, Ulrika
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Food choice in fallow deer – experimental studies of selectivity2007Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    In this thesis, I experimentally investigate feeding selectivity in fallow deer (Dama dama), with respect to plant secondary compounds, especially tannins, which can decrease the quality of foods. I found that fallow deer avoided foods with higher amounts of tannic acid and Quebracho tannin, even though the deer ate some high-tannin food. The food choice was strongly dependent on the context in which the food was presented, so that the food choice in relation to tannin content was relative rather than absolute. When high-tannin food occurred at low frequency, the deer ate proportionally less from this type of food, at least when the difference in tannin content between the two foods was large. A basic implication is that an unpalatable plant type could benefit from its unpalatability, especially when occurring at low frequency. In experiments with two patches, the finding of a stronger within- than between-patch selectivity was mirrored in associational effects. First, low-tannin, palatable food was more eaten when occurring in a high-tannin patch, which corresponds to neighbour contrast susceptibility. Second, high-tannin, unpalatable food in a less defended patch was less eaten, which corresponds to neighbour contrast defence. A proximate cause of the associational effects can be the presence of a simultaneous negative contrast, which was experimentally demonstrated in an additional study. Individual differences in selectivity were present early in life and were consistent over five years, and selectivity was correlated with foraging exploratory behaviour. The results from this thesis suggest that fallow deer are selective in their food choice with respect to tannins from the beginning, and that the frequency of occurrence of different foods, but also the distance between foods and the complexity of presentation, influence the food choice. It is also suggested that a foraging behavioural syndrome is present in mammalian herbivores.

  • 21. Almeida, Joao
    et al.
    Schobesberger, Siegfried
    Kuerten, Andreas
    Ortega, Ismael K.
    Kupiainen-Maatta, Oona
    Praplan, Arnaud P.
    Adamov, Alexey
    Amorim, Antonio
    Bianchi, Federico
    Breitenlechner, Martin
    David, Andre
    Dommen, Josef
    Donahue, Neil M.
    Downard, Andrew
    Dunne, Eimear
    Duplissy, Jonathan
    Ehrhart, Sebastian
    Flagan, Richard C.
    Franchin, Alessandro
    Guida, Roberto
    Hakala, Jani
    Hansel, Armin
    Heinritzi, Martin
    Henschel, Henning
    Jokinen, Tuija
    Junninen, Heikki
    Kajos, Maija
    Kangasluoma, Juha
    Keskinen, Helmi
    Kupc, Agnieszka
    Kurten, Theo
    Kvashin, Alexander N.
    Laaksonen, Ari
    Lehtipalo, Katrianne
    Leiminger, Markus
    Leppa, Johannes
    Loukonen, Ville
    Makhmutov, Vladimir
    Mathot, Serge
    McGrath, Matthew J.
    Nieminen, Tuomo
    Olenius, Tinja
    Onnela, Antti
    Petaja, Tuukka
    Riccobono, Francesco
    Riipinen, Ilona
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Rissanen, Matti
    Rondo, Linda
    Ruuskanen, Taina
    Santos, Filipe D.
    Sarnela, Nina
    Schallhart, Simon
    Schnitzhofer, Ralf
    Seinfeld, John H.
    Simon, Mario
    Sipila, Mikko
    Stozhkov, Yuri
    Stratmann, Frank
    Tome, Antonio
    Troestl, Jasmin
    Tsagkogeorgas, Georgios
    Vaattovaara, Petri
    Viisanen, Yrjo
    Virtanen, Annele
    Vrtala, Aron
    Wagner, Paul E.
    Weingartner, Ernest
    Wex, Heike
    Williamson, Christina
    Wimmer, Daniela
    Ye, Penglin
    Yli-Juuti, Taina
    Carslaw, Kenneth S.
    Kulmala, Markku
    Curtius, Joachim
    Baltensperger, Urs
    Worsnop, Douglas R.
    Vehkamaki, Hanna
    Kirkby, Jasper
    Molecular understanding of sulphuric acid-amine particle nucleation in the atmosphere2013Inngår i: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 502, nr 7471, s. 359-+Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nucleation of aerosol particles from trace atmospheric vapours is thought to provide up to half of global cloud condensation nuclei(1). Aerosols can cause a net cooling of climate by scattering sunlight and by leading to smaller but more numerous cloud droplets, which makes clouds brighter and extends their lifetimes(2). Atmospheric aerosols derived from human activities are thought to have compensated for a large fraction of the warming caused by greenhouse gases(2). However, despite its importance for climate, atmospheric nucleation is poorly understood. Recently, it has been shown that sulphuric acid and ammonia cannot explain particle formation rates observed in the lower atmosphere(3). It is thought that amines may enhance nucleation(4-16), but until now there has been no direct evidence for amine ternary nucleation under atmospheric conditions. Here we use the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN and find that dimethylamine above three parts per trillion by volume can enhance particle formation rates more than 1,000-fold compared with ammonia, sufficient to account for the particle formation rates observed in the atmosphere. Molecular analysis of the clusters reveals that the faster nucleation is explained by a base-stabilization mechanism involving acid-amine pairs, which strongly decrease evaporation. The ion-induced contribution is generally small, reflecting the high stability of sulphuric acid-dimethylamine clusters and indicating that galactic cosmic rays exert only a small influence on their formation, except at low overall formation rates. Our experimental measurements are well reproduced by a dynamical model based on quantum chemical calculations of binding energies of molecular clusters, without any fitted parameters. These results show that, in regions of the atmosphere near amine sources, both amines and sulphur dioxide should be considered when assessing the impact of anthropogenic activities on particle formation.

  • 22.
    Almesjö, Lisa
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Limén, Helene
    Fiskpopulationer i svenska vatten. Hur påverkas de av fiske, övergödning och miljögifter?2008Rapport (Annet vitenskapelig)
  • 23.
    Almqvist, Gustaf
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Round goby Neogobius melanostomus in the Baltic Sea – Invasion Biology in practice2008Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Human mediated transfer of non-indigenous species is considered to be a major threat to global biodiversity. The Ponto-Caspian round goby (Neogobius melanostomus), which has established populations in various regions in Eurasia and North-America, was first observed in Gulf of Gdańsk, Baltic Sea, in 1990. In this thesis the round goby is used as case study for assessing the invasion process of an alien species in to the Baltic Sea. Factors governing life history characteristics, traits that have enhanced the invasion, and ecological consequences for the Baltic Sea are assessed. Two diverging life history strategies of the round goby related to habitat were found: one to-wards early maturation and short population turnover time in sheltered areas, the other towards high growth rate and late maturation in exposed areas. Females produced two batches in average during the spawning season. Lengths of spawning season and annual fecundity of round gobies in Gulf of Gdańsk were in the same range as in the donor region. The species was found to compete with juvenile flounder for space and food resources, and probably also other native species are affected in coastal areas. Round goby comprised a main food source for cod and perch, forming a new energetic pathway between mussels and predatory fish. It is predicted that the species must produce more than one batch per season to sustain a viable population. Low temperature in the northern Baltic Sea is expected to hamper the devel-opment of new round goby populations, however, the global climate change might change this situation. In the southern Baltic Sea a shortage of optimal reproduction habitats is suggested to moderate the rate of spread. Although round goby in the Gulf of Gdańsk seems to have passed abundance maximum it is likely that the species will continue to be an important ecosystem component, at least in southern Baltic Sea, in the future.

  • 24.
    Alonso Aller, Elisa
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Effects of Marine Protected Areas on Tropical Seagrass Ecosystems2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Seagrass beds are highly productive coastal ecosystems that sustain a rich and diverse associated fauna and flora. Increasing anthropogenic pressures threaten seagrass ecosystems and have already led to major seagrass losses across the world. Marine Protected Areas (MPAs) have become one of the key strategies to manage coastal ecosystems and associated resources worldwide and have been often shown to successfully protect marine ecosystems. However, relatively few studies have assessed the effects of MPAs on seagrass ecosystems, and there are indications that MPAs may not be able to fully protect seagrasses, especially from disturbances originating outside their boundaries. Within this context, this thesis aimed to investigate the direct and indirect effects (those mediated by biotic interactions) of MPAs on tropical seagrasses, associated fish communities, and ecosystem processes.

    The thesis consists of three parts. First, we used 10-years of seagrass monitoring data within a MPA to evaluate the temporal variability in seagrass cover and species composition in relation to changes in environmental conditions (Paper I). Second, we investigated the potential of MPAs to enhance the temporal stability of seagrass ecosystems using a 10-month field study. We surveyed seagrass-associated fish communities (Paper II) and estimated seagrass growth and herbivory rates (Paper III) during three different seasons within MPAs and unprotected sites. Finally, to evaluate the effects of MPAs and land-use on seagrass ecosystems we surveyed seagrass species and trait composition within government-managed MPAs, community-managed MPAs, and unprotected sites (Paper IV).

    The seagrass bed monitored in Paper I showed a high temporal and spatial variability, with a temporal decline in cover and change in species composition, followed by a period of recovery. This pattern could not be associated with any of the climate and tidal variables considered, suggesting that potential drivers of decline may have originated outside MPA boundaries. The results from the seasonal field study showed that MPAs increased the temporal stability of seagrass-associated fish communities, particularly juvenile fish (Paper II), and strengthened a positive link between herbivorous fish, herbivory rates, and seagrass growth (Paper III), suggesting the presence of a positive feedback that promotes stability. Finally, MPAs affected seagrass species and trait composition (by selecting for more stress-sensitive species) but did not seem to be able to protect seagrasses from land-use effects, with seagrasses showing similar changes in species and trait composition within and outside MPAs (Paper IV). Considering these results, this thesis builds to a body of literature indicating that MPAs alone may not be sufficient to protect seagrass ecosystems and that improved management strategies may be necessary to preserve these important coastal habitats.

  • 25.
    Alonso Aller, Elisa
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Gullström, Martin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Eveleens Maarse, Floriaan K. J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Gren, Michaela
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Nordlund, Lina Mtwana
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik. WIO CARE, Zanzibar, Tanzania.
    Jiddawi, Narriman
    Eklöf, Johan S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Single and joint effects of regional- and local-scale variables on tropical seagrass fish assemblages2014Inngår i: Marine Biology, ISSN 0025-3162, E-ISSN 1432-1793, Vol. 161, nr 10, s. 2395-2405Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Seagrass beds are highly important for tropical ecosystems by supporting abundant and diverse fish assemblages that form the basis for artisanal fisheries. Although a number of local- and regional-scale variables are known to influence the abundance, diversity and assemblage structure of seagrass-associated fish assemblages, few studies have evaluated the relative and joint (interacting) influences of variables, especially those acting at different scales. Here, we examined the relative importance of local- and regional-scale factors structuring seagrass-associated fish assemblages, using a field survey in six seagrass (Thalassodendron ciliatum) areas around Unguja Island (Zanzibar, Tanzania). Fish density and assemblage structure were mostly affected by two regional-scale variables; distance to coral reefs, which positively affected fish density, and level of human development, which negatively affected fish density. On the local scale, seagrass biomass had a positive (but weaker) influence on fish density. However, the positive effect of seagrass biomass decreased with increasing level of human development. In summary, our results highlight the importance of assessing how multiple local and regional variables, alone and together, influence fish communities, in order to improve management of seagrass ecosystems and their services.

  • 26.
    Amir, Omar A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Biology, ecology and anthropogenic threats of Indo-Pacific bottlenose dolphins in east Africa2010Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This thesis examines the biology, ecology and anthropogenic threats of Indo-Pacific bottlenose dolphins (Tursiops aduncus) off Zanzibar, Tanzania, based on research conducted and samples collected between 2000 and 2008. Distribution and occurrence are described based on incidental catches (bycatch) in gillnet fisheries. Biology and ecology are examined by ageing and studying the reproductive biology and stomach contents of collected specimens. The composition of organohalogen compounds is determined in blubber samples, and assessment and mitigation of bycatch are conducted using observers onboard fishing vessels. Fisheries bycatch data showed that Indo-Pacific bottlenose dolphins occur year round in all areas around Zanzibar. Sexual maturity was attained between 7 and 8 years and body length 190-200 cm in females and at 16 years and body length 213 cm in males. The gestation period was estimated to be 12.3 months, with calving occurring throughout the year, peaking November-March and with an interval of 2.7 years. The estimated pregnancy rate was between 0.10 and 0.58 depending on methods used. Stomach contents revealed a relatively large number of prey species, but that only a few small- and medium-sized neritic fish and cephalopods contribute substantially to the diet. Estimates of total annual bycatch were >9% which is not considered sustainable. An experiment showed that pingers can be a short term mitigation measure to reduce bycatch of dolphins in both drift- and bottom set gillnets. Methoxylated polybrominated diphenyl ethers (Meo-BDEs) were found at higher concentrations than anthropogenic organic pesticides (OCPs), with only traces of polychlorinated biphenyls (PCBs) detected. This study reveals the magnitude and apparent susceptibility of Indo-Pacific bottlenose dolphins off Zanzibar to anthropogenic threats, especially fisheries bycatch, and it is clear that immediate conservation and management measures are needed to reduce bycatch.

  • 27.
    Amir, Omar A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Berggren, Per
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Estimates of bycatch and field experiment using pingers to reduce bycatch of dolphins in drift- and bottom set gillnets in Menai Bay, Zanzibar, TanzaniaManuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    In order to estimate the total bycatch in gillnet fisheries and to assess the impact on dolphin populations in the Menai Bay Conservation Area, a survey using independent observers aboard the fishing vessels was conducted in 2003/2004. The observer programme covered 23.6% and 24.5% of the drift- and bottom set gillnets effort, respectively. The estimated total bycatch was 13 Indo-Pacific bottlenose dolphins in drift gillnets and 4 humpback dolphins in bottom set gillnets representing 9.6% and 6.3%, respectively of the estimated 136 Indo-Pacific bottlenose and 63 humpback dolphins resident in the area in 2002. These bycatch levels were not considered sustainable. In 2007/2008 a second observer programme was conducted in the same area to investigate the effectiveness of acoustic alarms (pingers) in reducing the bycatch of dolphins in the drift- and bottom set gillnets. The observed effort in the drift gillnets was 257 sets without pingers and 251 sets with pingers representing 21% and 20% of the total recorded effort, respectively. Six dolphins were bycaught during the pinger experiment in the drift gillnets (1 Indo-Pacific bottlenose dolphin in sets with pingers and 4 Indo-Pacific bottlenose dolphins and 1 spinner dolphin in the sets without pingers). In the bottom set gillnet fishery, the observed fishing effort was 236 sets without pingers and 224 sets with pingers, representing 28% and 27% of the total recorded effort, respectively. In the bottom set gillnets, one humpback dolphin was bycaught in the sets without pingers and no dolphin was bycaught in the sets with pingers. Pingers reduced the bycatch of dolphins in both drift- and bottom set gillnets, however the reduction was only significant in the drift gillnets. Estimates of the total bycatch in the sets without pingers in 2007/2008 fishing season were 16 Indo-Pacific bottlenose dolphins in drift gillnets and 3 humpback dolphins in the bottom set gillnet fishery, representing 11.8% and 4.8% of estimated population size for respective species in the area in 2002. Given the documented unsustainable removal levels in the drift- and bottom set gillnets, immediate management actions are needed to reduce dolphin bycatch in these fisheries.

  • 28.
    Amir, Omar A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Berggren, Per
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Jiddawi, Narriman
    Growth and reproduction of Indo-Pacific bottlenose dolphins (Tursiops aduncus) incidentally caught in gillnets off Zanzibar, TanzaniaArtikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Life history parameters of Indo-Pacific bottlenose dolphin (Tursiops aduncus) were examined in 69 specimens incidentally caught in gillnet fisheries off Zanzibar, Tanzania between 2000 and 2008. Calves were born at a body length of 103 cm and a weight of 12-15 kg. Sexual maturity in females was reached at 7-8 years and body length 190-200 cm. Sexual maturity in males was attained at 16 years and a body length of 213 cm. Calving occurred throughout the year with a peak November-March, after a gestation period of 12.3 months. The estimated pregnancy rate was 0.10 based on the proportion pregnant mature females in the sample and 0.58 based on the occurrence of Corpora Lutea in the ovaries. The average calving interval was calculated to 2.7 years. The results are important for assessment of fisheries bycatch mortality and conservation and management of Indo-Pacific bottlenose dolphins in western Indian Ocean

  • 29.
    Amir, Omar A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Berggren, Per
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Ndaro, Simon
    Jiddawi, Narriman
    Feeding ecology of the Indo-Pacific bottlenose dolphin (Tursiops aduncus) incidentally caught in the gillnet fisheriesoff Zanzibar, Tanzania2005Inngår i: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 63, nr 3, s. 429-437Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The stomach contents of 26 Indo-Pacific bottlenose dolphins (Tursiops aduncus) incidentally caught in gillnet fisheries aroundUnguja Island (Zanzibar) between February 2000 and August 2002 were examined. The relative importance of each prey species wasassessed through indices of relative importance. In total, 1403 prey items comprising 50 species of bony fish and three species ofsquid were identified from food remains. Five species of fish, Uroconger lepturus, Synaphobranchus kaupii, Apogon apogonides,Lethrinus crocineus, Lutjanus fulvus, and three species of squid, Sepioteuthis lessoniana, Sepia latimanus and Loligo duvauceli, werethe most important prey species. Based on an index that included frequency of occurrence, percentage by number and by weight,Uroconger lepturus proved to be the most important prey species of mature dolphins whereas Apogon apogonides was the preferredprey of immature dolphins. These results indicate that Indo-Pacific bottlenose dolphins off the coast of Zanzibar forage ona relatively large number of prey species, but that only a few small- and medium-sized neritic fish and cephalopods contributesubstantially to the diet. Further, the ecology and behavior of the preferred fish prey species indicate that the dolphins forage overreef or soft bottom substrata and near the shore.

  • 30.
    Amir, Omar A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Jiddawi, Narriman
    Berggren, Per
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    The occurrence and distribution of dolphins in Zanzibar, Tanzania, with comments on the differences between two species of Tursiops2005Inngår i: Western Indian Ocean journal of marine science, ISSN 0856-860X, Vol. 4, nr 1, s. 85-93Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Incidental catches (bycatch) in gillnet fisheries off Zanzibar (Unguja Island), as asource of mortality among several species of dolphins, were reported in a questionnaire surveyconducted in 1999. As a follow-up to that survey, from January 2000 to August 2003, wemonitored the incidental catches of dolphins collected from 12 fish landing sites. Six species ofdolphins were recorded from 143 specimens retrieved from bycatches in drift- and bottom setgillnets. Of these, 68 (48%) were Indo-Pacific bottlenose dolphins (Tursiops aduncus), 44 (31%) spinner dolphins (Stenella longirostris), 12 (8%) Risso’s dolphins (Grampus griseus), 11 (8%) Indo-Pacific humpback dolphins (Sousa chinensis), 6 (4%) Pan-tropical spotted dolphins(Stenella attenuata) and 2 (1%) common bottlenose dolphins (Tursiops truncatus). Most of thebycatches (71%) were in nets set off the north coast of Unguja Island. In this paper, bycatchrecords are examined to describe the occurrence and distribution of dolphin species in UngujaIsland coastal waters. The relatively large numbers of bycatch dolphins recorded indicate thatbycatch may be a potential threat to local populations that need to be addressed in futureconservation and management efforts in the region.

  • 31. Anderies, J. M.
    et al.
    Carpenter, S. R.
    Steffen, Will
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre. Australian National University, Australia.
    Rockström, Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    The topology of non-linear global carbon dynamics: from tipping points to planetary boundaries2013Inngår i: Environmental Research Letters, ISSN 1748-9326, E-ISSN 1748-9326, Vol. 8, nr 4, s. 044048-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a minimal model of land use and carbon cycle dynamics and use it to explore the relationship between non-linear dynamics and planetary boundaries. Only the most basic interactions between land cover and terrestrial, atmospheric, and marine carbon stocks are considered in the model. Our goal is not to predict global carbon dynamics as it occurs in the actual Earth System. Rather, we construct a conceptually reasonable heuristic model of a feedback system between different carbon stocks that captures the qualitative features of the actual Earth System and use it to explore the topology of the boundaries of what can be called a 'safe operating space' for humans. The model analysis illustrates the existence of dynamic, non-linear tipping points in carbon cycle dynamics and the potential complexity of planetary boundaries. Finally, we use the model to illustrate some challenges associated with navigating planetary boundaries.

  • 32. Anderies, John M.
    et al.
    Folke, Carl
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Walker, Brian
    Östrom, Elinor
    Aligning Key Concepts for Global Change Policy: Robustness, Resilience, and Sustainability2013Inngår i: Ecology & society, ISSN 1708-3087, E-ISSN 1708-3087, Vol. 18, nr 2, s. 8-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Globalization, the process by which local social-ecological systems (SESs) are becoming linked in a global network, presents policy scientists and practitioners with unique and difficult challenges. Although local SESs can be extremely complex, when they become more tightly linked in the global system, complexity increases very rapidly as multi-scale and multi-level processes become more important. Here, we argue that addressing these multi-scale and multi-level challenges requires a collection of theories and models. We suggest that the conceptual domains of sustainability, resilience, and robustness provide a sufficiently rich collection of theories and models, but overlapping definitions and confusion about how these conceptual domains articulate with one another reduces their utility. We attempt to eliminate this confusion and illustrate how sustainability, resilience, and robustness can be used in tandem to address the multi-scale and multi-level challenges associated with global change.

  • 33.
    Andersen Borg, Marc
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Non-indigenous zooplankton: the role of predatory cladocerans and of copepods in trophic dynamics2009Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Human-mediated introductions of non-indigenous species now threaten to homogenize the biota of the Globe, causing huge economic and ecological damage. This thesis studies the ecological role of 3 invasive planktonic crustaceans, the omnivorous copepod Acartia tonsa (western Atlantic and Indo-Pacific) and the predatory cladocerans, Cercopagis pengoi (Ponto-Caspian) and Bythotrephes longimanus (Eurasian). B. longimanus invaded the North American Great Lakes in 1982, C. pengoi the Baltic in 1992 and the Great Lakes in 1999, while A. tonsa has an extensive invasion history that includes the Baltic.

    We review current knowledge on feeding biology of the predatory cladocerans. A study of stable C and N isotope ratios indicated mesozooplankton as the main food source of C. pengoi in the northern Baltic Sea proper, with young C. pengoi also eating microzooplankton, such as rotifers. Young-of-the-year herring did eat C. pengoi and herring trophic position shifted from 2.6 before the invasion to 3.4 after, indicating that C. pengoi had been “sandwiched” into the modified food web between mesozooplankton and fish.

    Salinity tolerance experiments on Acartia tonsa and co-occurring Acartia clausi showed the formers euryhaline character and high grazing potential. Energy partitioning between ingestion, production and respiration was rather constant over the tested salinity range of 2 to 33, with small differences in gross growth efficiency and cost of growth, but maximum ingestion at 10-20. Egg hatching in A. tonsa was only reduced at the lowest salinity. Extreme changes in salinity were needed to cause significant mortality of A. tonsa in the field, but its feeding activity could be severely reduced by salinity changes likely to occur in estuaries. A study of a hypertrophic estuary showed that A. tonsa can sustain a population despite very high mortality rates, caused by predation, high pH and low oxygen, helping explain the success of A. tonsa as an invader of estuaries.

  • 34. Andersen, Liselotte
    et al.
    Olsen, Morten
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för genetik, mikrobiologi och toxikologi.
    Distribution and population structure of North Atlantic harbour seals2010Inngår i: NAMMCO scientific publications, ISSN 1560-2206, E-ISSN 2309-2491, Vol. 8, s. 15-36Artikkel i tidsskrift (Fagfellevurdert)
  • 35. Anderson, Pippin
    et al.
    Elmqvist, Thomas
    Stockholms universitet, Stockholm Resilience Centre.
    Urban Ecological and Social-Ecological Research in the City of Cape Town: Insights Emerging from an Urban Ecology CityLab2012Inngår i: Ecology & society, ISSN 1708-3087, E-ISSN 1708-3087, Vol. 17, nr 4, s. 23-Artikkel i tidsskrift (Fagfellevurdert)
  • 36.
    Andersson, Erik
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen.
    Ahrné, Karin
    Department of Ecology, Swedish University of Agricultural Sciences.
    Pyykönen, Markku
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen. Stockholms universitet, Stockholm Resilience Centre.
    Elmqvist, Thomas
    Stockholms universitet, Naturvetenskapliga fakulteten, Systemekologiska institutionen. Stockholms universitet, Stockholm Resilience Centre.
    Patterns and scale relations among urbanization measures in Stockholm, Sweden2009Inngår i: Landscape Ecology, ISSN 0921-2973, E-ISSN 1572-9761, Vol. 24, s. 1331-1339Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study we measure urbanization based on a diverse set of 21 variables ranging from landscape indices to demographic factors such as income and land ownership using data from Stockholm, Sweden. The primary aims were to test how the variables behaved in relation to each other and if these patterns were consistent across scales. The variables were mostly identified from the literature and limited to the kind of data that was readily accessible. We used GIS to sample the variables and then principal component analyses to search for patterns among them, repeating the sampling and analysis at four different scales (250 × 250, 750 × 750, 1,250 × 1,250 and 1,750 × 1,750, all in meters). At the smallest scale most variables seemed to be roughly structured along two axes, one with landscape indices and one mainly with demographic factors but also impervious surface and coniferous forest. The other land-cover types did not align very well with these two axes. When increasing the scale this pattern was not as obvious, instead the variables separated into several smaller bundles of highly correlated variables. Some pairs or bundles of variables were correlated on all scales and thus interchangeable while other associations changed with scale. This is important to keep in mind when one chooses measures of urbanization, especially if the measures are indices based on several variables. Comparing our results with the findings from other cities, we argue that universal gradients will be difficult to find since city shape and size, as well as available information, differ greatly. We also believe that a multivariate gradient is needed if you wish not only to compare cities but also ask questions about how urbanization influences the ecological character in different parts of a city.

  • 37.
    Andersson, Erik
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Barthel, Stephan
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Borgström, Sara
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Colding, Johan
    Elmqvist, Thomas
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Folke, Carl
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre. Royal Swedish Academy of Science, Beijer Institute, Sweden.
    Gren, Åsa
    Reconnecting Cities to the Biosphere: Stewardship of Green Infrastructure and Urban Ecosystem Services2014Inngår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 43, nr 4, s. 445-453Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Within-city green infrastructure can offer opportunities and new contexts for people to become stewards of ecosystem services. We analyze cities as social-ecological systems, synthesize the literature, and provide examples from more than 15 years of research in the Stockholm urban region, Sweden. The social-ecological approach spans from investigating ecosystem properties to the social frameworks and personal values that drive and shape human interactions with nature. Key findings demonstrate that urban ecosystem services are generated by social-ecological systems and that local stewards are critically important. However, land-use planning and management seldom account for their role in the generation of urban ecosystem services. While the small scale patchwork of land uses in cities stimulates intense interactions across borders much focus is still on individual patches. The results highlight the importance and complexity of stewardship of urban biodiversity and ecosystem services and of the planning and governance of urban green infrastructure.

  • 38.
    Andersson, Mathias H.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Offshore wind farms - ecological effects of noise and habitat alteration on fish2011Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    There are large gaps in our understanding how fish populations are affected by the anthropogenic noise and the alteration of habitat caused by the construction and operation of offshore wind farms. These issues are of great importance as the construction of offshore wind farms will increase all over the world in the near future. This thesis studies these effects with a focus on fish. The wind turbine foundations function as artificial reefs and are colonized by invertebrates, algae and fish. The epibenthic assemblages are influenced by factors such as hydrographical parameters, time of submergence, distance to natural hard bottom, material and texture (PAPER I, II). Once an epibenthic assemblage has been developed, fish utilize it for different ecosystem services such as food, shelter, and spawning and nursery area. Benthic and semi-pelagic species show a stronger response to the introduced foundation than pelagic species, as it is the bottom habitat that has mainly been altered (PAPER I, II). Pelagic species could be positively affected by the increased food availability - but it takes time and the effect is local.

    Construction noise like pile driving creates high levels of sound pressure and acoustic particle motion in the water and seabed. This noise induces behavioural reactions in cod (Gadus morhua) and sole (Solea solea). These reactions could occur up to tens of kilometres distance from the source (PAPER III). During power production, the wind turbines generate a broadband noise with a few dominating tones (PAPER IV, V), which are detectable by sound pressure sensitive fish at a distance of several kilometres even though intense shipping occurs in the area. Motion sensitive species will only detect the turbine noise at around a ten meter distance. Sound levels are only high enough to possibly cause a behavioural reaction within meters from a turbine (PAPER IV, V).

  • 39.
    Andersson, Mathias H.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Berggren, Matz
    Wilhelmsson, Dan
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Öhman, Marcus C
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen.
    Epibenthic colonization of concrete and steel pilingsin a cold-temperate embayment: a feld experiment2009Inngår i: Helgoland Marine Research, ISSN 1438-387X, E-ISSN 1438-3888, Vol. 63, nr 3, s. 249-260Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    With large-scale development of offshore wind farms, vertical structures are becoming more common in open water areas. To examine how vertical structures of different materials may be colonized by epibenthic organisms, an experiment was carried out using steel and concrete pilings constructed to resemble those commonly used in wind farm constructions as well as in bridges, jetties and oil platforms. The early recruitment and succession of the epibenthic communities were sampled once a month for the first 5 months and then again after 1 year. Further, the fish assemblages associated with the pillars were sampled and compared to natural areas. The main epibenthic species groups, in terms of coverage, diVered between the two materials at five out of six sampling occasions. Dominant organisms on steel pillars were the barnacle Balanus improvisus,the calcareous tubeworm Pomatoceros triqueter and the tunicate Ciona intestinalis. On the concrete pillars, the hydroid Laomedea sp. and the tunicates Corella parallelogramma and Ascidiella spp. dominated. However, there was no different in coverage at different heights on the pillars or in biomass and species abundance at different directions (north-east or south-west) 5 months after submergence. Fish showed overall higher abundances and species numbers on the pillars (but no difference between steel and concrete)compared to the surrounding soft bottom habitats but not compared to natural vertical rock walls. Two species were attracted to the pillars, indicating a reef effect; Gobiusculus flavescens and Ctenolabrus rupestris. The bottom-dwelling gobies, Pomatoschistus spp., did not show such preferences.

  • 40.
    Andersson, Mathias H
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Dock-Åkerman, Emily
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Ubral-Hedenberg, Ramona
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Öhman, Marcus C
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Sigray, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Swimming Behavior of Roach (Rutilus rutilus) and Three-spined Stickleback Gasterosteus aculeatus) in Response to Wind Power Noise and Single tone frequencies2007Inngår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 36, nr 8, s. 636-638Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Human-induced underwater noise is drastically increasing as the result of offshore installations and human activities in the marine environment. Many of these structures and activities produce low-frequency noise that could potentially disturb or have harmful effects on several species of teleost fishes. Within the next decade, thousands of wind turbines will be in use in coastal and offshore waters and there is increasing concern on how they may influence marine life. The aims of this study were to examine how swimming behavior of roach (Rutilus rutilus) and three-spined stickleback (Gasterosteus aculeatus) were influenced by single-frequency sounds and noise generated by an offshore wind turbine, and the function of sound pressure level.

  • 41.
    Andersson, Mathias H
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Gullström, Martin
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Asplund, Maria E
    Department of Marine Ecology, Göteborg University.
    Öhman, Marcus C
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Importance of Using Multiple Sampling Methodologies for Estimating of Fish Community Composition in Offshore Wind Power Construction Areas of the Baltic Sea2007Inngår i: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 36, nr 8, s. 634-636Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It is standard procedure that an Environmental Impact Assessment (EIA) is conducted before larger constructions are built. To adequately describe the impact, methods used in an EIA should be carefully adapted considering both the character of the constructions under development and the environment that will be affected. Various sampling techniques are applied to estimate fish abundances and species composition. Methods used, including trawling, seine and gill netting, angling, echo-sound sampling, fishery data, video recordings, dredging, and visual counts using SCUBA, will all give different estimates of fish community composition.

  • 42.
    Andersson, Mathias H.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Sigray, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Persson, Leif K. G.
    FOI.
    Wind farm noise influence on the audibility of fishManuskript (preprint) (Annet vitenskapelig)
  • 43.
    Andersson, Mathias H.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Öhman, Marcus C.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Fish and sessile assemblages associated with wind-turbineconstructions in the Baltic Sea2010Inngår i: Marine and Freshwater Research, ISSN 1323-1650, E-ISSN 1448-6059, Vol. 61, nr 6, s. 642-650Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Offshore wind farms are being built at a high rate around the world to meet the demand for renewable energy. We studied fish and sessile communities on and around offshore wind-turbine foundations in the southern Baltic Sea, 7 years after construction, using visual census techniques to determine how fish, sessile-invertebrate and algal communities are affected by the introduction of such structures. Fish assemblages were dominated by two-spotted gobies (Gobiusculus flavescens) that were found in large shoals in close association with the vertical surface. At the seabed, close to the foundation, the black goby (Gobius niger) was recorded in large numbers. The most obvious difference in fish densities was found between wind-power foundations extending through the entire water column and the surrounding open waters. Fouling assemblages on the vertical foundation surfaces and at the seabed just below differed from those at the seabed further away by having higher coverage of blue mussel (Mytilus edulis) and less algal growth. The results from the present study suggest that the introduction of offshore wind turbines in marine waters could have a positive effect on fish numbers and the presence of sessile invertebrates

  • 44.
    Andersson, Petter
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen.
    Quantitative aspects of plant-insect interactions in fragmented landscapes:  the role of insect search behavior2009Bok (Annet vitenskapelig)
    Abstract [en]

    Insects searching for host plants in the landscape are challenged by habitat fragmentation and heterogeneity. Host plants or habitat are usually distributed in scattered patches that may differ in size, shape and isolation. The ability of finding these patches strongly depends on the insect´s search behavior and the sensory cues used for detecting and locating patches. Here, I describe sensory systems of insects, such as vision, olfaction and taste, in relation to host plant search. I discuss quantitative patterns of insect distributions and density-area relations arising from search behavior. Migration pattern may be strongly affected by the cue used by the insect in the patch detection process. The relation between visual cues and patch size is well known, but we lack knowledge about how olfactory cues are connected to patch size. Since search behavior affects the spatial distribution of insects, I briefly describe consequences for host plants. Finally, I describe the main objectives of my PhD-project.

  • 45.
    Andersson, Petter
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen.
    The importance of search behavior and movements for spatial distributions of herbivorous insects2011Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Insect populations commonly show large spatial variation in density, and much variation have been shown to be explained by the search behavior applied by the insect when locating habitat patches. This thesis explores the importance of odor-mediated attraction for immigration rates of herbivorous insects in relation to the size of the patches and the density of host plants within the patches. By using electroantennogram and measuring moth antennal responses to sex pheromones and thereby estimating the relative odor-mediated attraction from odor patches in field experiments (Paper I, III), I show that the length of the odor plumes emanating from the patches increase proportional with the square-root of the number of odor sources. In laboratory and field experiments (with the weevils Cionus scrophulariae and C. tuberculosus and the host plant figwort Scrophularia nodosa; Paper II) and meta-analyses on multiple insect herbivores (Paper III), I examined whether the relative increase in plume length could also predict the immigration rates of olfactory searching insects in relation to patches with increasing area and increasing density of host plants. The experiments (Paper II) and meta-analyses (Paper III) showed that the observed immigration rates of olfactory searching insects was well predicted by the relative increase in plume length, as estimated from the electroantennogram measurements (Paper I, III). The importance of immigration rates, relative to the effect of emigration and local growth was also investigated for the Cionus weevils in natural S. nodosa patches (Paper IV). This study showed that the density-patch size relationships of the weevils during early season were predicted by the net scaling of emigration and immigration rates, and differences in density-patch size relationships between the two species could be explained by inter-specific differences in their emigration rates from small patches. In conclusion, this thesis shows that search behavior can be used to predict immigration rates and spatial distributions of insects, with implications for pest control, conservation ecology and general ecological theory.

  • 46.
    Andersson, Petter
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen.
    Hambäck, Peter A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen.
    Immigration of olfactory searching insects into host plant patches: testing scaling rules for olfactory information2011Inngår i: Arthropod-Plant Interactions, ISSN 1872-8855, E-ISSN 1872-8847, Vol. 5, s. 269-277Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Herbivorous insects are commonly faced with host plants being distributed in scattered patches across a landscape. Immigration rates into habitat patches may strongly depend on the sensory cues used in the patch location process, and immigration rates of insects can be predicted based on the scaling of sensory cues. Here, we tested recent estimates of the scaling of olfactory information to patch size, which predicts a scaling coefficientf z = -0.5 (A^z, where A = patch size, z = scaling coefficient). We predicted that immigration rates of olfactory searching insects into patches of different sizes should scale according to the estimated slope. We investigated attraction of the weevils Cionus tuberculosus and Cionus scrophulariae to odors from figwort Scrophularia nodosa and quantified immigration rates of weevils into differently sized patches. We also investigated oviposition rates of the sawfly Tenthredo scrophulariae. The slope in the regression between density and patch size for herbivores was then compared with the predicted scaling coefficient. Using olfactometers, we found that weevils were attracted to figwort odors. Weevil densities were significantly affected by patch size, and the slope in the relationship between density and patch size was z = -0.53. The slope in the relationship between larval densities of sawflies and patch size was less negative with a slope of z = -0.15, indicating differences in search behavior compared with the weevils. The density–patch size relationship for the weevils closely matched the predicted slope and supported the previous estimations of the scaling of olfactory informationto patch size.

  • 47.
    Andersson, Petter
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Löfstedt, Christer
    Lund Univ, Dept Biol..
    Hambäck, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Insect density-plant density relationships: a modified view of insect responses to resource concentrations2013Inngår i: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 173, nr 4, s. 1333-1344Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Habitat area is an important predictor of spatial variation in animal densities. However, the area often correlates with the quantity of resources within habitats, complicating our understanding of the factors shaping animal distributions. We addressed this problem by investigating densities of insect herbivores in habitat patches with a constant area but varying numbers of plants. Using a mathematical model, predictions of scale-dependent immigration and emigration rates for insects into patches with different densities of host plants were derived. Moreover, a field experiment was conducted where the scaling properties of odour-mediated attraction in relation to the number of odour sources were estimated, in order to derive a prediction of immigration rates of olfactory searchers. The theoretical model predicted that we should expect immigration rates of contact and visual searchers to be determined by patch area, with a steep scaling coefficient, mu = -1. The field experiment suggested that olfactory searchers should show a less steep scaling coefficient, with mu a parts per thousand -0.5. A parameter estimation and analysis of published data revealed a correspondence between observations and predictions, and density-variation among groups could largely be explained by search behaviour. Aphids showed scaling coefficients corresponding to the prediction for contact/visual searchers, whereas moths, flies and beetles corresponded to the prediction for olfactory searchers. As density responses varied considerably among groups, and variation could be explained by a certain trait, we conclude that a general theory of insect responses to habitat heterogeneity should be based on shared traits, rather than a general prediction for all species.

  • 48.
    Andersson, Petter
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Löfstedt, Christer
    Hambäck, Peter A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    How insects sense olfactory patches: the spatial scaling of olfactory information2013Inngår i: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 122, nr 7, s. 1009-1016Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    When searching for resources in heterogeneous environments, animals must rely on their abilities to detect the resources via their sensory systems. However, variation in the strength of the sensory cue may be mediated by the physical size of the resource patch. Patch detection of insects are often predicted by the scaling of sensory cues to patch size, where visual cues has been proposed to scale proportional to the diameter of the patch. The scaling properties of olfactory cues are, however, virtually unknown. Here, we investigated scaling rules for olfactory information in a gradient of numbers of odour sources, relevant to odour-mediated attraction under field conditions. We recorded moth antennal responses to sex pheromones downwind from pheromone patches and estimated the slope in the scaling relationship between the effective length of the odour plumes and the number of odour sources. These measurements showed that the effective plume length increased proportional to the square root of the number of odour sources. The scaling relationship, as estimated in the field experiment, was then evaluated against field data of the slope in the relationship between trap catch and release rate of chemical attractants for a wide range of insects. This meta-analysis revealed an average slope largely consistent with the estimated scaling relationship between the effective plume length and the number of odour sources. This study is the first to estimate the scaling properties of olfactory cues empirically and has implications for understanding and predicting the spatial distributions of insects searching by means of olfactory cues in heterogeneous environments.

  • 49.
    Andersson, Petter
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen.
    Löfstedt, Christer
    Hambäck, Peter A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Botaniska institutionen.
    Insect density-plant density relationships – a modified view of insect responses to resource concentrationsArtikkel i tidsskrift (Fagfellevurdert)
  • 50.
    Andesson, Mathias H.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Zoologiska institutionen, Avdelningen för zoologisk ekologi.
    Sigray, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Particle motion measured at an operational wind turbine in relation to hearing sensitivity in fishManuskript (preprint) (Annet vitenskapelig)
1234567 1 - 50 of 1126
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