Integrating multiple indices of geobiodiversity reveals a series of regional species-rich areas worthy of conservation in the region of the Qinghai-Tibet Plateau

Abstract

While there is a general understanding of broadscale patterns of the region of the Qinghai-Tibet Plateau (QTP)'s biodiversity, this is largely reliant upon knowledge of species richness. Less known is the correlation between species richness and other measures of biodiversity, and how this correlation varies among different types of taxa. Using county-level seed plant data for the QTP region, we identified and compared regional species-rich areas, using six indices quantifying taxonomic, endemic and phylogenetic diversity for distinct plant types (trees, shrubs, herbs, endemic/non-endemic, alpine/non-alpine/non-alpine-endemic plants). We modelled diversity for each index and plant types using predictors of contemporary climate, topography and historical factors. We found a high congruence between species richness and phylogenetic diversity, which showed a consistent gradient from high values in the southeast to low values in the northwest. We confirm that this known pattern was largely associated with contemporary climatic and topographic predictors. There was a similarly high congruence of species-rich areas among plant types, except for alpine species. Strikingly, we identified species-rich areas which were previously unrecognized. Their identification largely derives from a low congruence between general patterns and patterns predicted by corrected weighted endemism. Nine of these species-rich areas are located where coverage in nature reserves is absent or inadequate, highlighting clear conservation gaps in the regional conservation strategy. Our study is the first to compare taxonomic, endemic and phylogenetic diversity for different plant types in the QTP region. Thus, it provides the essential bases for designing strategies for local to regional biodiversity conservation.