Ecosystem greenspots pass the first test

Susan F Gould,Luciana L Porfirio,Brendan Mackey,Sonia Hugh

doi:10.1007/s10980-014-0112-1

Susan F Gould, Luciana L Porfirio + Show 2 more

Open Access

https://doi.org/10.1007/s10980-014-0112-1

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Abstract

Given climate change projections, the ability to identify locations that provide refuge under drought conditions is an urgent conservation priority. Previously, it has been proposed that the ecosystem greenspot index could be used to identify locations that currently function as habitat refuges from drought and fire. If this is true, these locations may have the potential to function as climate-change micro-refuges. In this study we aimed to: (1) test whether ecosystem greenspot indices are related to vegetation specific gradients of habitat resources; and (2) identify environmental correlates of the ecosystem greenspots. Ecosystem greenspot indices were calculated for two vegetation types: a woodland and a grassland, and compared with in situ data on vegetation structure. There were inaccuracies in the identification of the grassland greenspot index due to fine scale spatial heterogeneity and misclassification. However, the woodland greenspot index accurately identified vegetation specific gradients in the biomass of the relevant framework species. The spatial distribution of woodland greenspots was related to interacting rainfall, soil and landscape variables. The ability to provide information about variation in resources, and hence habitat quality, within specific vegetation types has immediate applications for conservation planning. This is the first step toward validating whether the ecosystem greenspot index of Mackey et al. (Ecol Appl 22:1852–1864, 2012) can identify potential drought micro-refuges. More work is needed to (1) address sources of error in identifying specific vegetation types; (2) refine the analysis and field validation methods for grasslands; and (3) to test whether species persistence during drought is supported by identified greenspots.

Highlights

Climate projections indicate that drought frequency and severity is likely to increase over much of eastern Australia over the coming century (Hennessy et al 2007; White et al 2010)
Locations where conditions are such that species can persist in situ while their populations are generally contracting in range or abundance have been termed cryptic refugia and micro-refuges
The woodland greenspot index was a good predictor of variation in the basal area, and biomass, of the framework species, E. viminalis

Summary

Introduction

Climate projections indicate that drought frequency and severity is likely to increase over much of eastern Australia over the coming century (Hennessy et al 2007; White et al 2010). Species can respond in one of three ways to changing environmental conditions: extinction, adaptation or stasis. Evidence from the Pleistocene shows that species responses to climatic oscillations varied with topography, latitude and individual species characteristics (Hewitt 2004). The most typical response was evolutionary stasis in situ combined with changes in distribution and abundance (Stewart and Lister 2001; Byrne 2008; Magri 2008; Provan and Bennett 2008; Kearns et al 2010). Locations where conditions are such that species can persist in situ while their populations are generally contracting in range or abundance have been termed cryptic refugia and micro-refuges. The ability to identify potential climate change microrefuges is a research and conservation priority (Keppel et al 2011; Sublette Mosblech et al 2011)

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