Measuring burrows as a feasible non-destructive method for studying the population dynamics of ghost crabs

Abstract

The use of ghost crabs in environmental quality assessments of sandy beaches is supported by their ecological role and abundance. This study evaluated the spatial distribution and population dynamics of Ocypode quadrata by the non-destructive method of counting and measuring its burrows. Additionally, individuals were captured, weighed, sexed and had their carapaces and burrows measured for correlation analysis. The density of burrows differed statistically among beach levels and seasons, but did not differ among beach sectors. The population showed a bimodal distribution during most of the year, with a small shift in modal peaks. Estimation of growth parameters suggested that our population was slow-growing and long-lived, despite reaching sexual maturity early. These characteristics could be related to the survival strategy of this species in a hostile environment. Growth curves plotted against burrow diameter and carapace width showed no statistical differences, demonstrating that burrow counting and measuring is a feasible low-impact method to infer ghost crab population dynamics.