Trapdoor spider (Cantuaria dendyi)

Mohamed bin Zayed Species project number 13256662

My research will explore the ecology and conservation issues surrounding New Zealand's endemic trapdoor spider genus, Cantuaria, focusing on C. dendyi. Cantuaria spp. primarily inhabit humid forests and grasslands throughout New Zealand (Forster & Forster 2005). Their apparent lack of dispersal ability has resulted in many species being locally endemic (Hitchmough, Leigh, & Cromarty, 2005), and therefore susceptible to decline due to habitat destruction.

The only New Zealand representatives of the family Idiopidae, Cantuaria spp. are important forest and grassland predators; conserving them will help to preserve New Zealand's endemic biodiversity, and maintain fragile ecosystems. Cantuaria dendyi is the type species for the genus Cantuaria, distributed in miniscule populations around Christchurch and Banks Peninsula. Its habitat is fragmented by agriculture and invasive vegetation, but the impacts of such disturbance on C. dendyi are unknown.

Aims

• To investigate the ecology of Cantuaria spp.

By examining the distribution, range sizes and habitat types preferred by Cantuaria spp., I hope to elucidate how different microhabitats affect their population demographics, growth rates and survivorship. Quadrat sampling for C. dendyi burrows will reveal what features are correlated with high abundance, and therefore which areas of habitat are of highest conservation priority. Male C. dendyi will be tracked using harmonic radar to study their dispersal patterns.

• To uncover the conservation statuses of Cantuaria spp.

The genus Cantuaria includes many data deficient species (Sirvid et al., 2012). Smaller patches of habitat may harbour declining species and require protection to preserve them. I will survey Cantuaria spp. in forests and grasslands using the New Zealand Threat Classification System (Stringer & Hitchmough, 2012) to reveal their conservation statuses and study their distribution.

• To identify threats to Cantuaria caused by anthropogenic activity

Some habitat patches are situated near anthropogenically disturbed areas. Surveying land either side of obstacles such as roads and towns using burrow counts will show whether distance from an obstacle affects population density. Comparing fixation indices across an obstacle will show whether there is gene flow between populations found on both sides of the obstacle. By researching Cantuaria spp. in their natural habitat, finding the habitat requirements of individual species and threats to their existence, I will catalyse in situ conservation of Cantuaria spp., many of which are likely threatened by habitat loss and disturbance. Although C. dendyi will be the focus of my research, the entire genus will be considered in order to address the paucity of published literature on Cantuaria spp.