Canadian Forest Service Publications
Habitat network topology influences the importance of ecological traps in metapopulations. 2020. Edge, C.B.; Fortin, M.J. Ecosphere 11 (5)
Issued by: Atlantic Forestry Centre
Catalog ID: 40593
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The majority of species exist in metapopulations, where populations are linked to one another through dispersal. Disturbances (natural or anthropogenic) are known to affect population vital rates which can reverberate to the metapopulations through dispersal, which is determined by the topology of the habitat network (i.e., the number of patches and their spatial layout). Within a habitat network, disturbed patches become sinks or ecological traps depending on whether individuals avoid or are attracted to the disturbed patch. Ecological traps occur when individuals preferentially disperse to patches that result in low fitness which can have severe consequences for metapopulations. However, the effects of ecological traps should be considered relative to a number of factors, such as the number of disturbed patches, the fitness cost of the disturbance, and dispersal. Further, the relative importance of each factor can vary among different habitat network topologies according to the position and role of the disturbed patches for maintaining the functional connectivity of the entire metapopulation. Using a spatially explicit stochastic stage-based metapopulation model based on amphibian life history, we investigate how the number of disturbed patches, fitness cost of the disturbance, dispersal rate, and attractiveness of disturbed habitat patches affect the persistence of metapopulations in different habitat network topologies (random, tree, and full). Overall, dispersal, the number of disturbed patches, and the fitness penalty of the disturbance were the most important factors affecting mean metapopulation growth rate, the probability of extinction, and time to extinction. Ecological traps had the largest effect in the tree network topology where the number of links between patches was limited. For all network topologies studied, larger negative effects were observed when disturbed patches were centrally located in the network. Reducing the number and spatial correlation of disturbances is known to be a reliable conservation strategy, we add the importance of considering the location of disturbances within habitat networks and network topology.
Plain Language Summary
The vast majority of species persist within metapopulations, which consist of individual populations within habitat patches that are linked by dispersal. When disturbances occur in a habitat patch, there is an effect on that particular population, and there could be effects on other populations that are linked to it through dispersal or the broad metapopulation that occurs at the landscape scale. When land management occurs at a broad spatial and long temporal scale, effects on the metapopulation are of more concern than those on individual populations because the metapopulation allows the species to persist over long time periods. In the present paper, we use a spatially explicit, stochastic, stage-based population model to evaluate the consequences of disturbances in three different habitat networks. We demonstrate that dispersal, the number of disturbances, and the fitness penalty of the disturbance are the most important factors determining the persistence of metapopulations and that the importance of these factors varies among the habitat networks. This paper presents the theory and general application of the population model, which will be used in future work to explore and make predictions for real-world scenarios in the forestry sector.