Abstract
An important challenge in theoretical ecology is to better predict ecological responses to environmental change, and in particular to spatial changes such as habitat fragmentation. Classical food-web models have focused on purely ecological predictions, without taking adaptation or evolution of species traits into account. We address this issue using an eco-evolutionary model, which is based on body masses and diets as the key traits that determine metabolic rates and trophic interactions. The model implements evolution by the introduction of new morphs that are related to the existing ones, so that the network structure itself evolves in a self-organized manner. We consider the coupling and decoupling of habitats in multi-trophic metacommunities consisting of 2 or 4 habitats. Our model thus integrates metacommunity models, which describe ecosystems as networks of networks, with large community evolution models. We find that rescue effects and source-sink effects occur within coupled habitats, which have the potential to change local selection pressures so that the local food web structure shows a fingerprint of its spatial conditions. Within our model system, we observe that habitat coupling increases the lifetimes of top predators and promotes local biodiversity.
Highlights
IntroductionEcologist currently observe alarmingly high extinction rates, with spatial changes (such as habitat fragmentation or habitat loss due to land use) being one of the most important drivers[1, 2]
All over the world, ecologist currently observe alarmingly high extinction rates, with spatial changes being one of the most important drivers[1, 2]
Gravel et al studied complex food webs that were locally prone to extinctions, but whose complexity was observed to promote their persistence through regional dynamics[13]
Summary
Ecologist currently observe alarmingly high extinction rates, with spatial changes (such as habitat fragmentation or habitat loss due to land use) being one of the most important drivers[1, 2]. Gravel et al studied complex food webs that were locally prone to extinctions, but whose complexity was observed to promote their persistence through regional dynamics[13]. Richhardt et al.[19] analysed this effect in more detail and found that the connectance and the centrality of the migration network topology best predict its impact on the local food webs. It is surprising that they all agree on one very important observation: The coupling of several communities can enhance local biodiversity and food web stability. It is important to note that this is only true for idealized systems that neglect various spatial processes, such as the spreading of diseases or the invasion of fundamentally different alien species, which might lead to negative effects of habitat coupling on local diversity
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