| 1. |
- Brännström, Åke, 1975-, et al.
(författare)
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Emergence and maintenance of biodiversity in an evolutionary food-web model
- 2011
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Ingår i: Theoretical Ecology. - : Springer Science+Business Media B.V.. - 1874-1738 .- 1874-1746. ; 4:4, s. 467-478
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Tidskriftsartikel (refereegranskat)abstract
- Ecological communities emerge as a consequence of gradual evolution, speciation, and immigration. In this study, we explore how these processes and the structure of the evolved food webs are affected by species-level properties. Using a model of biodiversity formation that is based on body size as the evolving trait and incorporates gradual evolution and adaptive radiation, we investigate how conditions for initial diversification relate to the eventual diversity of a food web. We also study how trophic interactions, interference competition, and energy availability affect a food web’s maximum trophic level and contrast this with conditions for high diversity. We find that there is not always a positive relationship between conditions that promote initial diversification and eventual diversity, and that the most diverse food webs often do not have the highest trophic levels.
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| 2. |
- Brännström, Åke, et al.
(författare)
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Modelling the ecology and evolution of communities : a review of past achievements, current efforts, and future promises
- 2012
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Ingår i: Evolutionary Ecology Research. - 1522-0613 .- 1937-3791. ; 14:5, s. 601-625
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Tidskriftsartikel (refereegranskat)abstract
- Background: The complexity and dynamical nature of community interactions make modelling a useful tool for understanding how communities develop over time and how they respond to external perturbations. Large community-evolution models (LCEMs) are particularly promising, since they can address both ecological and evolutionary questions, and can give rise to richly structured and diverse model communities.Questions: Which types of models have been used to study community structure and what are their key features and limitations? How do adaptations and/or invasions affect community formation? Which mechanisms promote diverse and stable communities? What are the implications of LCEMs for management and conservation? What are the key challenges for future research?Models considered: Static models of community structure, demographic community models, and small and large community-evolution models.Conclusions: Large community-evolution models encompass a variety of modelled traits and interactions, demographic dynamics, and evolutionary dynamics. They are able to reproduce empirical community structures. They have already generated new insights, such as the dual role of competition, which limits diversity through competitive exclusion yet facilitates diversity through speciation. Other critical factors determining eventual community structure are the shape of trade-off functions, inclusion of adaptive foraging, and energy availability. A particularly interesting feature of LCEMs is that these models not only help to contrast outcomes of community formation via species assembly with those of community formation via gradual evolution and speciation, but that they can furthermore unify the underlying invasion processes and evolutionary processes into a single framework.
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| 3. |
- Dakos, Vasilis, et al.
(författare)
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Ecosystem tipping points in an evolving world
- 2019
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Ingår i: Nature Ecology & Evolution. - : Springer Science and Business Media LLC. - 2397-334X. ; 3:3, s. 355-362
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Forskningsöversikt (refereegranskat)abstract
- There is growing concern over tipping points arising in ecosystems because of the crossing of environmental thresholds. Tipping points lead to abrupt and possibly irreversible shifts between alternative ecosystem states, potentially incurring high societal costs. Trait variation in populations is central to the biotic feedbacks that maintain alternative ecosystem states, as they govern the responses of populations to environmental change that could stabilize or destabilize ecosystem states. However, we know little about how evolutionary changes in trait distributions over time affect the occurrence of tipping points and even less about how big-scale ecological shifts reciprocally interact with trait dynamics. We argue that interactions between ecological and evolutionary processes should be taken into account in order to understand the balance of feedbacks governing tipping points in nature.
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| 4. |
- Lundström, Niklas L. P., 1980-, et al.
(författare)
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Meeting yield and conservation objectives by harvesting both juveniles and adults
- 2019
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Ingår i: American Naturalist. - : University of Chicago Press. - 0003-0147 .- 1537-5323. ; 193:3, s. 373-390
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Tidskriftsartikel (refereegranskat)abstract
- Sustainable yields that are at least 80% of the maximum sustainable yield are sometimes referred to as "pretty good yields" (PGY). The range of PGY harvesting strategies is generally broad and thus leaves room to account for additional objectives besides high yield. Here, we analyze stage-dependent harvesting strategies that realize PGY with conservation as a second objective. We show that (1) PGY harvesting strategies can give large conservation benefits and (2) equal harvesting rates of juveniles and adults is often a good strategy. These conclusions are based on trade-off curves between yield and four measures of conservation that form in two established population models, one age-structured model and one stage-structured model, when considering different harvesting rates of juveniles and adults. These conclusions hold for a broad range of parameter settings, although our investigation of robustness also reveals that (3) predictions of the age-structured model are more sensitive to variations in parameter values than those of the stage-structured model. Finally, we find that (4) measures of stability that are often quite difficult to assess in the field (e.g., basic reproduction ratio and resilience) are systematically negatively correlated with impacts on biomass and size structure, so that these later quantities can provide integrative signals to detect possible collapses.
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| 5. |
- Norberg, Jon, et al.
(författare)
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Eco-evolutionary responses of biodiversity to climate change
- 2012
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Ingår i: Nature Climate Change. - 1758-678X .- 1758-6798. ; 2:10, s. 747-751
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Tidskriftsartikel (refereegranskat)abstract
- Climate change is predicted to alter global species diversity(1), the distribution of human pathogens' and ecosystem services(3). Forecasting these changes and designing adequate management of future ecosystem services will require predictive models encompassing the most fundamental biotic responses. However, most present models omit important processes such as evolution and competition(4,5). Here we develop a spatially explicit eco-evolutionary model of multi-species responses to climate change. We demonstrate that both dispersal and evolution differentially mediate extinction risks and biodiversity alterations through time and across climate gradients. Together, high genetic variance and low dispersal best minimized extinction risks. Surprisingly, high dispersal did not reduce extinctions, because the shifting ranges of some species hastened the decline of others. Evolutionary responses dominated during the later stages of climatic changes and in hot regions. No extinctions occurred without competition, which highlights the importance of including species interactions in global biodiversity models. Most notably, climate change created extinction and evolutionary debts, with changes in species richness and traits occuring long after climate stabilization. Therefore, even if we halt anthropogenic climate change today, transient eco-evolutionary dynamics would ensure centuries of additional alterations in global biodiversity.
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| 6. |
- Robinson, Kathryn M, et al.
(författare)
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Relative impacts of environmental variation and evolutionary history on the nestedness and modularity of tree-herbivore networks
- 2015
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Ingår i: Ecology and Evolution. - : Wiley-Blackwell. - 2045-7758. ; 5:14, s. 2898-2915
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Tidskriftsartikel (refereegranskat)abstract
- Nestedness and modularity are measures of ecological networks whose causative effects are little understood. We analyzed antagonistic plant-herbivore bipartite networks using common gardens in two contrasting environments comprised of aspen trees with differing evolutionary histories of defence against herbivores. These networks were tightly connected owing to a high level of specialization of arthropod herbivores that spend a large proportion of the life cycle on aspen. The gardens were separated by ten degrees of latitude with resultant differences in abiotic conditions. We evaluated network metrics and reported similar connectance between gardens but greater numbers of links per species in the northern common garden. Interaction matrices revealed clear nestedness, indicating subsetting of the bipartite interactions into specialist divisions, in both the environmental and evolutionary aspen groups, although nestedness values were only significant in the northern garden. Variation in plant vulnerability, measured as the frequency of herbivore specialization in the aspen population, was significantly partitioned by environment (common garden) but not by evolutionary origin of the aspens. Significant values of modularity were observed in all network matrices. Trait-matching indicated that growth traits, leaf morphology, and phenolic metabolites affected modular structure in both the garden and evolutionary groups, whereas extra-floral nectaries had little influence. Further examination of module configuration revealed that plant vulnerability explained considerable variance in web structure. The contrasting conditions between the two gardens resulted in bottom-up effects of the environment, which most strongly influenced the overall network architecture, however, the aspen groups with dissimilar evolutionary history also showed contrasting degrees of nestedness and modularity. Our research therefore shows that, while evolution does affect the structure of aspen-herbivore bipartite networks, the role of environmental variations is a dominant constraint.
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| 7. |
- Romanuk, Tamara N., et al.
(författare)
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Simulated evolution assembles more realistic food webs with more functionally similar species than invasion
- 2019
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- While natural communities are assembled by both ecological and evolutionary processes, ecological assembly processes have been studied much more and are rarely compared with evolutionary assembly processes. We address these disparities here by comparing community food webs assembled by simulating introductions of species from regional pools of species and from speciation events. Compared to introductions of trophically dissimilar species assumed to be more typical of invasions, introducing species trophically similar to native species assumed to be more typical of sympatric or parapatric speciation events caused fewer extinctions and assembled more empirically realistic networks by introducing more persistent species with higher trophic generality, vulnerability, and enduring similarity to native species. Such events also increased niche overlap and the persistence of both native and introduced species. Contrary to much competition theory, these findings suggest that evolutionary and other processes that more tightly pack ecological niches contribute more to ecosystem structure and function than previously thought.
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