It is an unfortunate reality that conservation efforts are restricted by funding, which is typically provided by national or state governments, or by private donors. As such, a growing literature has focused on how to maximise return-on-investment (ROI) in conservation. The vast majority of this literature has hitherto been concerned primarily with identifying locations with high biodiversity value (e.g. species richness, functional diversity, ecosystem services) and low conservation costs (e.g. low land value and minimal value for economic activities, such as agriculture). However, much of the work done by the Conservation Planning Group has highlighted the importance of protecting not only areas with high biodiversity, but also areas under high threat of biodiversity loss. If areas unlikely to lose biodiversity are protected, such protection is likely to have made little difference compared to no protection at all (referred to as ‘residual conservation’).
In our new paper published in Conservation Letters (https://doi.org/10.1111/conl.12663), we explore the spatial relationship between conservation costs and threats from land clearing, using the case study of Queensland, Australia. It is widely assumed in conservation science that protecting high-threat areas will be expensive, and this assumption is used to justify targeting low-threat areas for protection. However, this assumption has yet to be empirically tested.
We found that, contrary to the widespread assumption of correlated threats and cost, there is no clear relationship between the two, with the relationship characterised by extreme amounts of variability (see figure below). The implications of this finding are significant. We show that conservation landscapes can be full of bargains: areas with low costs of protection, but that are under immense and imminent risk of biodiversity loss. As a result, it is essential that conservation planners quantify threats to biodiversity to identify these bargains, and avoid assuming that targeting low-threat areas is an effective way of minimising conservation costs.