Remote Sensing indicators and vertebrate biodiversity distribution in global drylands: An assessment with ESA Diversity II products

Remotely sensed estimates represent relevant tools for assessing biodiversity distribution, yet their relationships with functional groups across drylands have never been evaluated. We assessed relationship between bio-indicators derived by the ESA Diversity II project and distribution of terrestrial vertebrates in five drylands. Twenty seven bio-indicators were derived from MERIS data, including averages and inter-annual variability of seasonally aggregated proxies for net primary production, rainfall, soil moisture, rain use efficiency, and soil moisture use efficiency. For each dryland, the functional strategy of 739 terrestrial vertebrates was summarized into functional groups and predicted functional species richness was related with bio-indicators. Water availability was better related with functional species richness than net primary production estimates, suggesting water availability as a critical aspect shaping vertebrate distribution in drylands. Body size appeared as an important functional trait influencing vertebrate distribution across drylands, especially in small-sized species associated with water availability. Selected functional traits, quality of species presence data, and ecological modelling approaches affected analyses relating bio-indicators to vertebrate distribution. The 27 bio-indicators showed potential for biodiversity distribution assessments, and may be taken into consideration in future studies with appropriate model adaptations. The followed methodological approach could be applied to other drylands and even other ecosystems.