Remote assessments of human pressure on biodiversity may miss important human threats

Abstract

Monitoring human pressure on biodiversity within protected areas (PAs) remains a challenging task due to the vast number of PAs worldwide (> 250,000) and the fact that we lack basic information for most of them. Consequently, researchers are increasingly relying on remote sensing techniques to overcome this challenge. However, remote assessments of human pressure on biodiversity may miss crucial threats, such as hunting and invasive species, which are often best documented through in-situ field surveys. Here, we use a unique European Union dataset documenting human threats within 8,210 PAs through field surveys to assess the relationship between those threats and three commonly used indices of human pressure that are largely derived using remote-sensing methods—the Human Footprint and Human Modification indices and the LandScan Global Population Database. We find that the indices are not always related to the threats recorded within PAs through field surveys. The indices seem to best capture threats associated with urbanization, agriculture, and pollution but not necessarily others. Although remote assessments of human pressure on biodiversity are crucial for conservation, researchers and practitioners must be aware of their limitations and must complement such assessments with information collected in the field whenever possible.