Effects of land?use change on community diversity and composition are highly variable among functional groups

Abstract

In order to understand how the effects of land?use change vary among taxa and environmental contexts, we investigate how three types of land?use change have influenced phylogenetic diversity (PD) and species composition of three functionally distinct communities: plants, small mammals, and large mammals. We found large mammal communities were by far the most heavily impacted by land?use change, with areas of attempted large wildlife exclusion and intense livestock grazing, respectively, containing 164 and 165 million fewer years of evolutionary history than conserved areas (~40% declines). The effects of land?use change on PD varied substantially across taxa, type of land?use change, and, for most groups, also across abiotic conditions. This highlights the need for taxa?specific or multi?taxa evaluations, for managers interested in conserving specific groups or whole communities, respectively. It also suggests that efforts to conserve and restore PD may be most successful if they focus on areas of particular land?use types and abiotic conditions. Importantly, we also describe the substantial species turnover and compositional changes that cannot be detected by alpha diversity metrics, emphasizing that neither PD nor other taxonomic diversity metrics are sufficient proxies for ecological integrity. Finally, our results provide further support for the emerging consensus that conserved landscapes are critical to support intact assemblages of some lineages such as large mammals, but that mosaics of disturbed land?uses, including both agricultural and pastoral land, do provide important habitats for a diverse array of plants and small mammals