Establishing a baseline of plant diversity and endemism on a neotropical mountain summit for future comparative studies assessing upward migration: an approach from biogeography and nature conservation

Teresa Vegas-Vilarrúbia,Argelia Silva,Elisabet Safont,Otto Huber,Shingo Nozawa,Bruce K Holst,Valentí Rull,Yuribia Vivas

doi:10.1080/14772000.2014.918061

Abstract

Climate change is forcing many plant species to shift their range in search of adequate environmental conditions, being localized endemic species particularly at risk on mountain summits. The Pantepui biogeographic province, a set of flat-topped mountain summits (called tepuis) of northern South America, contains both high plant diversity and a high degree of endemism. Previous studies based on warming projections for the area suggested that half of the Pantepui endemic flora would disappear due to habitat loss by 2100. In this study, we selected one of the best-explored tepuis, Roraima-tepui, to establish the baseline of diversity and endemism for comparisons with historical data and future monitoring surveys, aimed at testing the hypothesis of upward migration of plants in response to global warming. We also analysed floristic and physiognomic features of the Eastern Tepui Chain (ETC, the mountain range where Roraima is located), and the phytogeographic patterns of both the ETC and Pantepui. The Roraima summit contains 227 species, including 44 new records, 13 exotic species (some of them with high invasive potential), and at least one species new to science. At the ETC level, Roraima is the tepui with highest species richness and degree of endemism, and shows a relatively high floristic similarity with Kukenán and Ilú. Herbaceous species dominate over shrubs on these tepuis, Tramen and Maringma, whereas on Yuruaní, Karaurín and Uei, they reach similar abundances. At the Pantepui level, endemic species have highly localized distribution patterns (17% local endemics). Conservation opportunities are evaluated in light of these results.

Highlights

Global warming is considered to be a major threat to high-mountain flora worldwide (Grabherr et al, 2010)
We suggest that patterns of vascular plant diversity and endemism in Pantepui should be 805 ideally studied using island biogeography techniques
The only information currently available for Pantepui concerning plant responses to climate change comes from models based on IPCC projections, which predict high 925 habitat loss by the end of this century associated with significant plant diversity declines on many tepuis (Rull & Vegas-Vilarrúbia, 2006; Nogué et al, 2009; Safont et al, 2012; Vegas-Vilarrúbia et al, 2012)

Summary

Introduction

Global warming is considered to be a major threat to high-mountain flora worldwide (Grabherr et al, 2010). As a response to climate change, plants may shift their distribution (e.g., Pauli et al, 2007; Kelly & Goulden, 2008; Lenoir et al, 2008; Feeley 55 et al, 2011; Jump et al, 2012), which can in turn produce the fragmentation or loss of their habitat (Thuiller et al, 2005; Colwell et al, 2008; Engler et al, 2011) Those inhabiting summits could find themselves without suitable substrate; in the case of endemic species, extinctions would result in biodiversity loss on a global scale (Rull & Vegas-Vilarrúbia, 2006; Kreyling et al, 2010; Dirnböck et al, 2011). The 0--5% reduction in mean annual rainfall forecasted by the IPCC scenario by the end of 105 this century (Christensen et al, 2007) is almost negligible, considering the perhumid climate of the tepui summits

Methods

Results

Discussion

Conclusion