Species with naturally small distribution ranges are termed short range endemic (SRE) species (Harvey 2002). Many species of terrestrial and aquatic invertebrates are SREs, including both surface and subterranean invertebrates. SRE species typically exhibit several life history traits including poor dispersal powers, confinement to discontinuous or rare habitats, slow growth and low fecundity (Harvey 2002).
In Western Australia, invertebrate groups that contain species which exhibit these life history traits include spiders, pseudoscorpions, schizomids, millipedes, slaters, land snails and others.
Harvey (2002) suggested a nominal distribution range of less than 10 000 square kilometres as a working definition for SRE species, although Eberhard et al. (2009) recommended a smaller area of less than 1000 square kilometres for stygofauna.
Because of their restricted distribution SREs are vulnerable to extinction from environmental changes and human impacts.
SRE invertebrates are important because they:
Trapdoor spider. This family (Idiopidae) contains numerous SRE species in Western Australia.