Ecological traits and conservation biology of five fossorial ‘sand-swimming’ snake species (Simoselaps: Elapidae) insouth-western Australia

Abstract

Although small, nocturnal, fossorial snakes are a significant component of the reptile fauna in many parts of the world, their biology is poorly known. An 11-year pit-trapping study in urban bushland remnants near the city of Perth, Western Australia, provided data from >500 captures of small fossorial snakes of the genus Simoselaps. The five species differed in relative abundances and in distribution, both among localities and among habitats within a single locality. For example, three saurophagous taxa (Simoselaps bertholdi, S. bimaculatus, S. calonotos) were most abundant in Banksia woodland, whereas two species that feed on reptile eggs (S. semifasciatus, S. fasciolatus) were most abundant in coastal heath. Capture rates for most species were low (for three of the five species, <one specimen captured per 1000 trapdays), and these taxa may be genuinely rare in most of the habitats that we surveyed. Activity patterns were highly seasonal, with little activity in winter or in midsummer. The two oophagous species showed a more restricted activity period (late spring–early summer) than did species with broader dietary habits. In the most abundant taxon (Simoselaps bertholdi), males were active mainly during spring (the mating season) and females during autumn, after oviposition. Capture rates and body condition of the captured snakes varied substantially among seasons and across years. Low capture rates mean that very prolonged surveys are needed to determine reliably whether or not a taxon occurs on any given site.