Further progress in reducing biodiversity loss depends on improving quantification of how drivers of habitat loss contribute to subsequent biodiversity impacts. Biodiversity impact metrics should be able to report linked trends in specific human activities and changes in biodiversity state, accounting for both the ecology of different species and the cumulative effects of historical habitat losses. These characteristics are not currently captured by a single metric.
The authors have therefore developed a globally applicable methodological framework that uses freely and publicly available datasets to quantify the relative impacts of human activities on biodiversity. They use species-specific habitat suitability models to link specific land uses to ensuing changes in the likelihood that local populations of those species will persist.
To illustrate the approach they assess the impacts of soy expansion and other land uses within the Brazilian Cerrado on over 2000 species of amphibians, birds, mammals and plants for three periods between 2000 and 2014. The results show that mammals and plants suffered the greatest overall reduction of suitable habitat. However, among endemic and near-endemic species – which face the greatest risk of global extinction from habitat conversion in the Cerrado – birds and mammals were the most affected groups.
While conversion of natural vegetation to grassland and planted pastures were together responsible for most of the biodiversity impact of recent changes, soy expansion (via direct conversion of natural vegetation) had the greatest impact per unit area. The total biodiversity impact of recent land-use change was concentrated in the southern states of the Cerrado: Minas Gerais, Goiás and Mato Grosso. However, the impact on biodiversity of soy production soy was greatest within the agricultural frontiers of Bahia and Piauí.
The authors suggest that the flexibility of the approach has clear potential to better characterize the pathways by which habitat loss drivers operate. Its capacity to incorporate species-specific ecological needs, through a globally applicable methodology, can improve the accuracy of biodiversity loss assessments.