| 1. |
- De Laender, Frederik, et al.
(författare)
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Mean species responses predict effects of environmental change on coexistence
- 2023
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Ingår i: Ecology Letters. - : WILEY. - 1461-023X .- 1461-0248. ; 26:9, s. 1535-1547
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Tidskriftsartikel (refereegranskat)abstract
- Environmental change research is plagued by the curse of dimensionality: the number of communities at risk and the number of environmental drivers are both large. This raises the pressing question if a general understanding of ecological effects is achievable. Here, we show evidence that this is indeed possible. Using theoretical and simulation-based evidence for bi- and tritrophic communities, we show that environmental change effects on coexistence are proportional to mean species responses and depend on how trophic levels on average interact prior to environmental change. We then benchmark our findings using relevant cases of environmental change, showing that means of temperature optima and of species sensitivities to pollution predict concomitant effects on coexistence. Finally, we demonstrate how to apply our theory to the analysis of field data, finding support for effects of land use change on coexistence in natural invertebrate communities.
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| 2. |
- Song, Chuliang, et al.
(författare)
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On the Consequences of the Interdependence of Stabilizing and Equalizing Mechanisms
- 2019
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Ingår i: American Naturalist. - : UNIV CHICAGO PRESS. - 0003-0147 .- 1537-5323. ; 194:5, s. 627-639
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Tidskriftsartikel (refereegranskat)abstract
- We present an overlooked but important property of modern coexistence theory (MCT), along with two key new results and their consequences. The overlooked property is that stabilizing mechanisms (increasing species niche differences) and equalizing mechanisms (reducing species fitness differences) have two distinct sets of meanings within MCT: one in a two-species context and another in a general multispecies context. We demonstrate that the two-species framework is not a special case of the multispecies one, and therefore these two parallel frameworks must be studied independently. Our first result is that, using the two-species framework and mechanistic consumer-resource models, stabilizing and equalizing mechanisms exhibit complex interdependence, such that changing one will simultaneously change the other. Furthermore, the nature and direction of this simultaneous change sensitively depend on model parameters. The second result states that while MCT is often seen as bridging niche and neutral modes of coexistence by building a niche-neutrality continuum, the interdependence between stabilizing and equalizing mechanisms acts to break this continuum under almost any biologically relevant circumstance. We conclude that the complex entanglement of stabilizing and equalizing terms makes their impact on coexistence difficult to understand, but by seeing them as aggregated effects (rather than underlying causes) of coexistence, we may increase our understanding of ecological dynamics.
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