Patterns of herbivore species richness in Kenya and current ecoclimatic stability

Abstract

The increased attention to biodiversity worldwide has stimulatedinterest in understanding biophysical factors associated with indicators ofbiodiversity such as species richness. Although levels of biodiversity may seemto be equivalent in different areas, high species richness may be caused byaccumulation of species over a long time in places where environmentalconditions remained stable and predictable. The advanced very high resolutionradiometer (AVHRR)–normalized difference vegetation index (NDVI) has beenestablished to be a good proxy for studying interannual climate variability aswell as regional drought condition. In this study, I examined the relationshipbetween large herbivore species richness and AVHRR–NDVI derivedclimatic-variability indices, interannual average NDVI and coefficient ofvariation of NDVI at a regional spatial scale in Kenya. Regions with a relativelylow coefficient of variation of NDVI and high interannual average NDVIcharacterize current ecoclimatic stability. By contrast, a high coefficient ofvariation of NDVI and relatively low interannual average NDVI characterizeecoclimatic instability (drought risk). Statistical analyses revealed that a highinterannual average NDVI increases species richness, whereas a high coefficient ofvariation of NDVI lowers species richness. This indicates that maximum numbers ofspecies are found in regions with current ecoclimatic stability. Understandingsuch relationships can help in explaining spatial distribution of speciesrichness and predicting global changes resulting from human impacts on theenvironment.