A practical approach to measuring the biodiversity impacts of land conversion

1. Further progress in reducing biodiversity loss relies on the improved
quantification of the connections between drivers of habitat loss and
subsequent biodiversity impacts. To this end, 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 within a single
metric. 2. Here we develop a globally applicable methodological framework
that uses freely and publicly available datasets to quantify the relative
impacts of anthropogenic activities on biodiversity. We 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 our approach we assess the impacts of soy
expansion and other land uses within the Brazilian Cerrado on over 2,000
species of amphibians, birds, mammals and plants for three periods between
2000 and 2014. 3.  Our results showed that mammals and plants
suffered the greatest overall reduction of suitable habitat. However,
among endemic and near-endemic species – which face 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 Geráis, Goiás
and Mato Grosso - but the impact on biodiversity of production of soy was
greatest within the agricultural frontiers of Bahía and Piauí. 4. The
flexibility of our approach to examine linkages between biodiversity loss
and specific human activities has clear potential to better characterise
the pathways by which habitat loss drivers operate. Its capacity to
incorporate species-specific ecological needs, through a globally
applicable methodology, can improve the tangibility of biodiversity loss
assessments.