Land sparing, land sharing, and the fate of Africa's lions.

Taxonomic bias in organismal research and conservation is well recognized, with focus disproportionately directed toward birds and mammals (1). Among mammals, carnivores often receive excessive attention and large carnivores are particularly well studied (2). Although papers reporting the population trends of a single species do not usually result in high-profile publications, an analysis of population trends from across the global range of a large carnivore (3) is now in PNAS. To allay concerns that this is simply more evidence of taxonomic bias, some justification is required. Here, I argue that the work of Bauer et al. (3) goes far beyond documenting population trends in a single species, posing, instead, fundamental questions about how biodiversity should function and where it should occur in the landscapes of the future. The once vast distribution of the lion (Panthera leo) (4) has contracted dramatically and, apart from an isolated population in India, the species is now restricted to sub-Saharan Africa. Within that range, habitat is highly fragmented and a previous, expert assessment identified 67 separate areas likely to contain resident lion populations (5). In their study, Bauer et al. (3) collate population estimates for 47 of these, representing all of the areas with repeated population estimates obtained by monitoring, and excluding only those for which estimates were based largely on extrapolation or expert opinion. Across these 47 areas, population estimates span an average of 13 y (range 4–47) with just over one estimate for every 2 y of monitoring. The data tell a bleak tale: lions in West and Central Africa and those in East Africa are declining, and are projected to continue to do so by 50% or more over the next two decades. The majority of populations that have been stable or increasing are in fenced reserves found in just four countries