Climate change impacts on body size and food web structure on mountain ecosystems

Lurgi M., López B.C., Montoya J.M. (2012) Climate change impacts on body size and food web structure on mountain ecosystems. Philosophical Transactions of the Royal Society B: Biological Sciences. 367: 3050-3057.
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Doi: 10.1098/rstb.2012.0239

Resum:

The current distribution of climatic conditions will be rearranged on the globe. To survive, species will have to keep pace with climates as they move. Mountains are among the most affected regions owing to both climate and land-use change. Here, we explore the effects of climate change in the vertebrate food web of the Pyrenees. We investigate elevation range expansions between two time-periods illustrative of warming conditions, to assess: (i) the taxonomic composition of range expanders; (ii) changes in food web properties such as the distribution of links per species and community size-structure; and (iii) what are the specific traits of range expanders that set them apart from the other species in the community-in particular, body mass, diet generalism, vulnerability and trophic position within the food web. We found an upward expansion of species at all elevations, which was not even for all taxonomic groups and trophic positions. At low and intermediate elevations, predator: prey mass ratios were significantly reduced. Expanders were larger, had fewer predators and were, in general, more specialists. Our study shows that elevation range expansions as climate warms have important and predictable impacts on the structure and size distribution of food webs across space. © 2012 The Royal Society.

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Novel communities from climate change

Lurgi M., López B.C., Montoya J.M. (2012) Novel communities from climate change. Philosophical Transactions of the Royal Society B: Biological Sciences. 367: 2913-2922.
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Doi: 10.1098/rstb.2012.0238

Resum:

Climate change is generating novel communities composed of new combinations of species. These result from different degrees of species adaptations to changing biotic and abiotic conditions, and from differential range shifts of species. To determine whether the responses of organisms are determined by particular species traits and how species interactions and community dynamics are likely to be disrupted is a challenge.Here, we focus on two key traits: body size and ecological specialization.We present theoretical expectations and empirical evidence on how climate change affects these traitswithin communities. We then explore howthese traits predispose species to shift or expand their distribution ranges, and associated changes on community size structure, food web organization and dynamics.We identify three major broad changes: (i) Shift in the distribution of body sizes towards smaller sizes, (ii) dominance of generalized interactions and the loss of specialized interactions, and (iii) changes in the balance of strong andweak interaction strengths in the short term. We finally identify two major uncertainties: (i) whether largebodied species tend to preferentially shift their ranges more than small-bodied ones, and (ii) how interaction strengths will change in the long term and in the case of newly interacting species. © 2012 The Royal Society.

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