Can the Iberian Floristic Diversity Withstand Near-Future Climate Change?

Marshall J Heap,Alastair Culham,Jonathan Lenoir,Rosario G Gavilán

doi:10.4236/oje.2015.417089

Abstract

We assess how effectively the current network of protected areas (PAs) across the Iberian Peninsula will conserve plant diversity under near-future (2020) climate change. We computed 3267 MAXENT environmental niche models (ENMs) at 1-km spatial resolution for known Iberian plant species under two climate scenarios (1950-2000 baseline & 2020). To predict near-future species distributions across the network of Iberian and Balearics PAs, we combined projections of species’ ENMs with simulations of propagule dispersal by using six scenarios of annual dispersal rates (no dispersal, 0.1 km, 0.5 km, 1 km, 2 km and unlimited). Mined PA grid cell values for each species were then analyzed. We forecast 3% overall floristic diversity richness loss by 2020. The habitat of regionally extant species will contract on average by 13.14%. Niche movement exceeds 1 km per annum for 30% of extant species. While the southerly range margin of northern plant species retracts northward at 8.9 km per decade, overall niche movement is more easterly and westerly than northerly. There is little expansion of the northern range margin of southern plant species even under unlimited dispersal. Regardless of propagule dispersal rate, altitudinal niche movement of +25 m per decade is strongest for northern species. Pyrenees flora is most vulnerable to near-future climate change with many northern plant species responding by shifting their range westerly and easterly rather than northerly. Northern humid habitats will be particularly vulnerable to near-future climate change. Andalusian National Parks will become important southern biodiversity refuges. With limited human intervention (particularly in the Pyrenees), we conclude that floristic diversity in Iberian PAs should withstand near-future climate change.

Highlights

IntroductionThe bulk of peer-reviewed literature on geographical patterns of species range shifts under contemporary and future climate change has focused on unidirectional (upward or poleward) and often unidimensional (latitudinal or elevational) range shifts
The bulk of peer-reviewed literature on geographical patterns of species range shifts under contemporary and future climate change has focused on unidirectional and often unidimensional range shifts
Biodiversity richness changes between the baseline and 2020 climate scenarios are positively correlated with increasing dispersal rates

Summary

Introduction

The bulk of peer-reviewed literature on geographical patterns of species range shifts under contemporary and future climate change has focused on unidirectional (upward or poleward) and often unidimensional (latitudinal or elevational) range shifts. Using a meta-analysis encompassing the animal and plant kingdoms, Chen and colleagues [1], observed a median rate of 11.0 m per decade upward and 16.9 km per decade poleward in species range shifts under contemporary climate change: two and three times faster than previously reported [2]. Still these are general tendencies and, as Chen and colleagues went on observing, there is a significant minority of species bucking these trends such as the downhill movement of 25% of the species they examined [1]. There were no distinct trends in climatic niche movement direction possibly due to the numbers of plant species considered (238 to 423 depending on region)

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