On the misuse of historical data to set conservation baselines: Wolves in Spain as an example

Long-term information on species trends is needed to accurately assess the magnitude of biodiversity change. Mining wildlife records from historical documents is a promising option to describe past species distributions and estimate conservation baselines. However, historical species records have multiple biases, and ignoring them can produce distorted views of past species distributions and misinform present-day environmental management. Here, we use recently published analyses of Iberian wolf (Canis lupus signatus) historical ranges in Spain to show how information gaps and biases in historical species accounts may lead to misleading conclusions about range trends and a downgrade of conservation targets. We call for the adoption of predictive models to assess historical species ranges for conservation and propose guidelines for the management and analysis of historical species records.