Home range, movement and habitat utilisation of the Carpentarian rock-rat (Zyzomys palatalis) in an isolated habitat patch

Abstract

Radio-telemetry was used to examine the home range, movement and habitat utilisation of the critically endangered Carpentarian rock-rat (Zyzomys palatalis) in an isolated habitat patch in the Gulf of Carpentaria hinterland over a 13-month period. Two home-range estimators were used in the study, (i) minimum convex polygon (MCP) and (ii) fixed Kernel (KL), the latter also being used to estimate core areas of activity. Based on a total sample size of 21 individuals, the mean MCP home range was 11 165 m2, similar to the mean KL home range of 10 687 m2. Core areas were, on average, 11.9% of the KL home-range estimate. There was no significant difference in the size of home range or core area of males and females. Juveniles had a significantly smaller home range than adults. Home ranges and, to a lesser degree, core areas were non-exclusive, with multiple areas of overlap (averaging 41% and 38% respectively) within and between all age and gender categories, but especially between males and between juveniles. Movement frequencies showed that animals made many short forays in a central area close to the arithmetic home-range mean and far fewer long forays of distances greater than 100 m from the central area. The spatial and temporal activity of Z. palatalis was concentrated in, but not confined to, the 'valley' and 'slope' habitats, with fewer movements of rats onto the surrounding 'plateau'. Resource selection analyses showed that Z. palatalis tended to prefer valley and slope habitats over the plateau and that the proportion of point locations was significantly higher for adults in the slope habitat and for juveniles in the valley habitat. Most home ranges were centred on the ecotone between these two habitat types. Although isolated and spatially limited, these habitat patches provide high-quality resources for dense populations of Z. palatalis. This study exemplifies a species' attempt to make efficient use of a limited resource in an otherwise hostile environment. Even small declines in habitat area or quality due to their vulnerability to fire would impact upon many animals.

Home range and den characteristics of the brush-tailed rabbit-rat (Conilurus penicillatus) in the monsoonal tropics of the Northern Territory, Australia

“…Note that the home-range calculations used only radio-tracking data: they did not include the location at which the individual was initially trapped. Other home-range studies carried out on small mammals in Australia have used these same techniques (see Pavey et al 2003;Puckey et al 2004). The MCP method draws the smallest convex polygon possible that takes in all known or estimated locations for the animal (Hayne 1949;Powell 2000).…”

“…Relatively few home-range studies using radio-tracking have been undertaken on rodents in Australia (but see Bubela et al 1991;Anstee et al 1997;Brandle and Moseby 1999;Cox et al 2000;Moro and Morris 2000), particularly so for rodents in the monsoonal tropics (but see Griffiths et al 2002;Puckey et al 2004). The present study concerns the home range and den characteristics of a little-known tropical rodent whose geographical distribution in the Northern Territory appears to have contracted (Woinarski 2000).…”

Variations in home range and core area of red-backed voles (Myodes regulus) in response to various ecological factors

“…Furthermore, several studies have also characterized the effects of seasonal factors on the distribution of rodents in relation to demographic factors 5,11,28 . However, topographic and cover factors, which are independent variables, have not been studied as much as other ecological factors [29][30][31] . Additionally, very few studies have comprehensively assessed the effects of various types of ecological factors on species distribution in South Korea.…”

Measure it to better manage it: a biodiversity monitoring framework for the Australian rangelands

“…Zyzomys palatalis,Puckey et al 2004; Gouldian Finch Erythrura gouldiae, O'Malley 2005; Julia Creek Dunnart Sminthopsis douglasi, DERM 2009b), and it is sensible to incorporate information from ongoing programs into the national rangeland monitoring framework. Additionally, the rangeland biodiversity monitoring framework could provide one mechanism for improved co-ordination and national reporting of such programs, which are currently ad-hoc and idiosyncratic.…”