Integrating disparate occurrence reports to map data-poor species ranges and occupancy: a case study of the Vulnerable bearded pig Sus barbatus

Abstract

AbstractMonitoring species ranges and suitable and occupied habitat are core components of biogeography, ecology and conservation biology, but it is difficult to do for rare, cryptic, wide-ranging, migratory or nomadic species. We present a transparent and objective process to combine multiple types of locality data (peer-reviewed and grey literature, museum collections, camera-trap inventories, and citizen science reports). We illustrate the advantages of this pooled approach by assessing change in range and patch occupancy for a data-poor and threatened nomadic keystone species, the bearded pig Sus barbatus, in Borneo, Sumatra and Peninsular Malaysia. We used a collated set of all occurrence observations (n = 240) to create minimum convex polygons for forested habitats for two time periods. We evaluated confidence that a patch was truly occupied by the overlap among data types. We found that 62% of the forest habitat of the Sumatran bearded pig S. barbatus oi was lost during 1990–2010 and that its range contracted by 76%; the Bornean bearded pig S. barbatus barbatus lost 23 and 24% of its forest habitat and range, respectively, and in Peninsular Malaysia the 93% range collapse of this subspecies during 1985–2010 is more severe than the 33% habitat loss alone would suggest. We conclude that integrating data types can improve mapping of the ranges of many data-poor species.