Search Results for density

.... The accuracy of habitat definition and mapping was tested by stratified transect counts of koala calls and sightings over two consecutive years (1997–98). Average koala density increased steeply and significantly, from 0.02 – 0.20 koalas/hectare, with increasing mapped habitat quality based on increasing...

... prior to and post significant rainfall events. Following this, top down regulation of fox populations during dry periods at sites where dingoes are retained may enable higher and more stable “baseline” densities of small vertebrates, from which a larger and more rapid rate of increase of these prey...

.... Nevertheless, several features of Koala ecology must be considered. Firstly, their sustainable density for any habitat is unknown. The fact that they were not discovered by European colonists during the first 10 years of settlement indicates that the original population density was very low near Sydney...

... these assessments because imperfect detection (false negatives) needs to be accounted for prior to estimating occupancy or density. Because male koalas are the primary sex that bellows, the method is sex-biased, although sex ratios for koalas are commonly 1:1. Further, assessment of sex-based habitat use is best...

... their behavioural adaptations to developed landscapes. This study compared the behaviour of eastern grey kangaroos in a developed environment to those surrounded by a natural environment. Data were collected using infra-red camera traps that recorded one minute videos. Population density was calculated using pellet...

...B. Law; L. Gonsalves; R. Bilney; J. Peterie; R. Pietsch; P. Roe; A. Truskinger ABSTRACT Cost-effective surveys of low density koala populations are challenging, but technological developments in the acoustics field offer great potential for landscape-scale surveys and monitoring. We assessed...

...A. R. Pople In order to monitor population trends through space and time, aerial surveys need to provide density estimates that are a constant proportion of the true population density and are therefore repeatable. Previous work has identified factors that affect the visibility of kangaroos from...

..., it was confirmed as one of the abundant wallabies on Kawau Island, Aotearoa New Zealand where they had been introduced a century before. N. parma is patchily distributed at low densities in moist forests along the Great Dividing Range in northern New South Wales. It is a Critical Weight Range macropod subject...

... detected during systematic surveys and 22 reptile species during targeted diurnal searches and opportunistic sightings. The highest species richness and density of reptiles were recorded in the logged New England Hardwood and Gorge Red Gum forest types. The Moist Hardwood type, with a closed mid-canopy had...

...A. Glen; C. Dickman This paper explores the question of why the endangered Spotted-tailed Quoll Dasyurus maculatus remains abundant in parts of north-eastern New South Wales, while populations in many other areas have declined or disappeared. Based on a two-year field study of a high-density...

...Frances Zewe; David Booth Many tadpole species aggregate in nature and if larval densities are not too high there is generally a positive effect of grouping on growth and development. The benefits of grouping may be due to social facilitation and the availability of other tadpoles' faeces...

...Peter R Mawson; Rick Dawson; Denis A Saunders ABSTRACT Barn Owls Tyto alba were recorded breeding in natural nest hollows in a Wandoo Eucalyptus wandoo woodland in the northern wheatbelt of Western Australia infrequently and at low densities during the period 1969-2022. During a record cropping...

... ) in suppressing Red Fox ( Vulpes vulpes ) populations in Australia has been investigated, with various data tending to show an inverse relationship between densities of the two species (e.g. Letnic et al. 2012; Johnson and VanDerWal 2009). There are very few examples in the literature where direct killing...

... detected electronically. The highest capture rate was in Jerrawangala National Park where 38 animals consisting of five species were trapped in one trap on a single night. The highest species richness and density was found in tall open forests, especially those along the Illawarra escarpment. Analysis...

... sex ratio, size structure, biomass, and density of Gambusia holbrooki populations in wetlands used for storage of 1) tertiary treated sewage effluent; 2) urban stormwater runoff; and 3) wetlands without effluent supplementation (control wetlands). Those wetlands that had previously been determined...

... of an agricultural weed for food has allowed the birds to increase their distribution and abundance, but is a potential threat to the cockatoos, as any control measure that severely reduces the density of Double Gee may adversely impact on the distribution of the cockatoos in the southern part of their range...