Scale, Variable Density, and Conservation Planning for Mammalian Carnivores

Abstract: Many mammalian carnivores are in local or global decline. To slow this process, continued planning to protect these species is warranted, Still, the data bases that we have at our disposal do not adequately document population requirements for space at scales appropriate for conservation planning. To illustrate this problem, we have collected published data for 214 population censuses of carnivores. We tested for a relationship between the number of individuals censused and the size of study site for our entire data set. We conducted the same test for each family, for which we obtained sufficient and qualifying census data With areas ranging from less than 10 km² to over 40,000 km², we obtained a significant regression (p < .001; r²= 76%) for the sample as a whole. We examined the distribution of densities with increasing area and found that the relationship was not constant but decreased We noticed that numbers per census-area size increased with a slope (m < 1). We also noticed that the sizes of study areas were unevenly distributed Only 7% of the studies in our sample censused regions larger than 10,000 km². It remains unclear to what extent and how the density decreases with increasing scale We expect that extrapolations from small scales to larger ones are likely to underestimate space requirements for carnivores.