Breaking ground: Quantitative fossorial herpetofaunal ecology in South Africa

Abstract

Basic ecological data are lacking for many species of herpetofauna, particularly fossorial species. Quantitative analyses of the factors that may influence the occurrence of fossorial herpetofaunal species are rare, with minimal work conducted in southern Africa. We mapped the absolute and relative fossorial herpetofaunal species richness across South Africa in order to highlight underlying trends in diversity. We also quantitatively surveyed fossorial herpetofauna at a site in Zululand, KwaZulu‐Natal, South Africa, using two methods. The first method has previously been used for surveying fossorial herpetofauna and involved two investigators excavating 28 clusters of five 1 m × 1 m × 0.3 m pits (total of 71 tons), placing all excavated soil on a plastic sheet and searching through the excavated soil by hand. The second method involved the use of heavy‐duty, earthmoving machinery to systematically excavate 193 m × 3 m × 1 m pits (total of 234 tons), passing all soil through a custom‐built table‐sieve to expose herpetofauna. At each site, soil compaction, particle size distribution, and land use were recorded. A Generalized Linear/Nonlinear Model (GLZ) was used to test for factors that predicted fossorial herpetofaunal density. Only seven specimens were captured from three species, yielding density estimates of between 0 and 0.4 individuals.m‐². None of the measured factors predicted fossorial herpetofaunal density, possibly because of the low capture rates. Our data indicate that fossorial herpetofauna occurrence was patchy and individuals occurred at low densities at the site. We explore several possible explanations for these patterns.