spatial ecology

Domestic cats (Felis catus) in Halfmoon Bay, Stewart Island/Rakiura, were tracked to assess the potential for incursions into native forest around the township, and into Rakiura National Park c. 5 km away. During February and April 2005, 15 and 4 radio-collared cats were tracked, respectively. During a six-month period, cat-owners logged prey brought home by 11 cats. Cats were at home >90% of the time. Of the six cats that left home, movements were small: home range was between 0.05 and 16.6 ha (100% minimum convex polygon).

>Spatial studies of ecology rarely look at small-scale spatial community organisation within multiple plots on multiple sites therefore it is difficult to draw conclusions that can be generalised. We hypothesised that small-scale spatial patterns of Festuca tussock grasslands should be consistent within a site and between various sites because their functional ecology is likely to be similar. Tussocks were mapped in 15 plots ranging in size from 56 to 400 m² spread over four sites.

Improvements in technology now make it possible to track animals of cat size using Global Positioning System (GPS)-telemetry. GPS technology has important advantages over traditional Very High Frequency (VHF)-radio tracking, but does incur higher per-tag costs. Budget is a limiting factor in experimental research; thus, an evaluation of the costs associated with both technologies according to the targets of a project should be undertaken before making any final decisions on the purchase of units and final experimental design.

The presence of feral cats (Felis catus) in the braided river valleys of New Zealand poses a threat to native species such as the critically endangered black stilt (Himantopus novaezelandiae). Trapping remains the most common method to control introduced predators, but trap placement criteria have not been fully informed by advances in the understanding of the spatial ecology of the pest species. We assessed the suitability of Global Positioning System (GPS) tags to study the spatial behaviour of feral cats in New Zealand braided rivers.