Multiannual analysis of chigüiro (Hydrochoerus hydrochaeris) population parameters in flooded savannas of colombia, towards its sustainable exploitation

Abstract

Sustainable use of wildlife requires information about the demographic parameters of free-ranging populations. Although exploitation of capybara populations occurs throughout its distribution, in Colombia its legal use has been suspended for two decades. The flooded savannas of Colombia and Venezuela that are home to the largest population of capybara are under high risk due to anthropic transformations. Here, we estimated the density, size, age structure, and group size of a population of capybara. We present information from seven samplings between the years 2004 and 2017. We established a 3600 ha grid with 700 m spaced transects in Paz de Ariporo, Casanare (Colombia). Three types of comparisons were made: 1) Interannual, equal climatic periods in samples of contiguous years, 2) Seasonal, different climatic periods of contiguous years, and 3) by decade, equal climatic periods in intervals of one decade. For all sampling, we calculated the finite population growth rate (λ), the maximum production index (Pmax), and only for the samplings that coincided with the harvesting period allowed in Colombia the sustained harvest index (h). In 2005, the population presented the largest size (N = 12 802, D = 3.75ind/ ha), while in 2017 it tended to decrease (N = 6928, D = 2.03ind/ ha). In the seasonal rain-dry comparisons, λ shows a decrease near to 30 %, while, per decade, there are positive and negative fluctuations. For the samplings in 2005 and 2015, (h), indicates that sustainable harvesting is viable, however, it is necessary the monitoring of the populations and their habitat.