Bioregionalization approaches for conservation: methods, biases, and their implications for Australian biodiversity

Abstract

Biogeographic classification schemes have been developed to prioritize biodiversity conservation efforts at large scales, but their efficacy remains understudied. Here we develop a systematic map of the literature on bioregional planning, based on a case study of the Interim Biogeographic Regionalization for Australia (IBRA), to identify where and how such schemes have been used in scientific research. We identified 67 relevant studies, finding that the majority investigated biodiversity exclusively within a single bioregion (65.7%), with 18 of these studies splitting the targeted bioregion based on administrative boundaries. Most used inferential techniques (74.6%) or pattern-based measures (68.7%), and few studies (9%) both considered biodiversity across multiple bioregions and compared findings between bioregions. Species were investigated ten times more frequently than ecosystems attributes, with mammals and birds monopolizing scientists’ attention. These findings show that our knowledge of biodiversity at bioregional scales is patchy, even for well-studied taxa, and that we have a limited understanding of the synthetic relationship between biodiversity and IBRA bioregions (which are demarcated according to other biophysical factors). This creates a barrier for systematic conservation planning, which requires unbiased information on the spatial attributes of biodiversity, and therefore this knowledge deficit warrants more attention.