Climate change in metacommunities: dispersal gives double-sided effects on persistence

Abstract

Climate change is increasingly affecting the structure and dynamics of ecological communities both at local and at regional scales, and this can be expected to have important consequences for their robustness and long-term persistence. The aim of the present work is to analyse how the spatial structure of the landscape and dispersal patterns of species (dispersal rate and average dispersal distance) affects metacommunity response to two disturbances: (i) increased mortality during dispersal and (ii) local species extinction. We analyse the disturbances both in isolation and in combination. Using a spatially and dynamically explicit metacommunity model, we find that the effect of dispersal on metacommunity persistence is two-sided: on the one hand, high dispersal significantly reduces the risk of bottom-up extinction cascades following the local removal of a species; on the other hand, when dispersal imposes a risk to the dispersing individuals, high dispersal increases extinction risks, especially when dispersal is global. Large-bodied species with long generation times at the highest trophic level are particularly vulnerable to extinction when dispersal involves a risk. This suggests that decreasing the mortality risk of dispersing individuals by improving the quality of the habitat matrix may greatly increase the robustness of metacommunities.

Climate change in size-structured ecosystems

“…However, warming may also increase the hostility of the landscape matrix surrounding the local habitats thus yielding higher extinction rates during dispersal. In an analysis of a spatially and dynamically explicit metacommunity model, community persistence was highest at intermediate levels of dispersal [12]. Persistence decreased towards low dispersal rates, because local bottom-up extinction cascades were not balanced by re-invasions.…”

“…Persistence decreased towards low dispersal rates, because local bottom-up extinction cascades were not balanced by re-invasions. However, high dispersal rates also decreased persistence due to high mortality experienced by the dispersing individuals [12]. Perdomo et al [22] complement this theoretical approach by addressing interactions between habitat fragmentation and warming in a laboratory experiment with moss communities.…”

“…This theme issue integrates novel approaches for addressing the consequences of climate change in complex, sizestructured ecosystems. This includes the development of novel concepts [7][8][9][10], model analyses [11][12][13] and empirical studies in marine [14,15], freshwater [16,17] and terrestrial ecosystems [18][19][20][21][22]. In the following, we will introduce the framework of this theme issue by describing the complexity and the size structure of natural communities and how they might interact with climate change in determining top-down or bottom-up control, community stability and spatial processes.…”

Present, Future, and Novel Bioclimates of the San Francisco, California Region

“…Very fine scale topoclimate variability becomes an important factor because short distance dispersal, such as from the other side of a canyon, may provide propagules for community recombination. This suggests differentiating the landscape into areas where the velocity of climate change is more or less important depending on the dispersal abilities of species [50], [51], [52] and taking advantage of higher resolution elevation data to better incorporate topoclimatic variation. Developing adaptive management strategies will be further challenged by ecosystem processes that are stimulated or exacerbated by increasing temperatures or changing precipitation patterns such as wildfires [53] and the increased photosynthetic efficiency in response to increasing levels of CO 2 [54], [55].…”

Connectivity of fragmented amphibian populations in a Neotropical landscape

“…Landscape connectivity has emerged as a key concept in conservation biology, landscape ecology, and population genetics, because the interaction between landscape structure and species responses drives ecologically and evolutionarily important processes (Kool et al 2013, Manel and. Among these processes, dispersal of individuals and geneflow are considered crucial for maintaining genetic diversity of local populations, allowing populations to respond to changing environments, and lowering risk of inbreeding depression and extinctions that translate to species loss at the community level (Frankham et al 2002, Campbell Grant et al 2010, Eklöf et al 2012.…”