Radiotelemetry and trapping were used to examine the home range and activity of Mastacomysfuscus Thomas in subalpine heathland at Smiggin Holes, N.S.W. The 75% utilisation contour was used to represent the home range. Its size varied between sexes and between seasons. During the mid-breeding season (January) male home ranges were larger than those of females. In late summer and autumn home ranges of males decreased and were no longer significantly larger than those of females. There was no significant variation in home ranges of females from January to autumn, although there was a slightly decreasing trend. In winter, individuals of both sexes congregated into communal nests, and home range decreased dramatically. Seasonal variation in home range is explained in terms of the social behaviour of the species. M. fuscus was mainly nocturnal but also exhibited some diurnal activity. There was no variation in activity between the sexes. Individuals were most active in January and February, became less active in March and late autumn, and were least active in winter.
Travelling paths and overnight roosts of the lace monitor, Varanus varius, were recorded by radiotracking during periods of up to 19 months in lowland open forest of south-eastern Australia. Home ranges were calculated by four methods: convex polygon (without correction for small sample size), convex polygon (with correction for small sample size), and two 95% probability ellipses. From field observations, I conclude that the convex polygon method without correction for sample size provides the most realistic description of the space used by V. varius. By this method, I calculated a mean (+/- s.d.) home range of 65 +/- 34 ha for 13 male V. varius (mean mass 5.1kg) that were radio-tracked for 2-19 months.
The Cross River gorilla (Gorilla gorilla diehli; hereafter: CRG) is one of the world's most endangered and least studied primates. CRG exist only in a patchy distribution in the southern portion of the Cameroon-Nigeria border region and may have as few as 300 individuals remaining, divided into 14 fragmented subpopulations. Though Western gorillas (Gorilla gorilla spp) probably once inhabited much greater ranges throughout West Africa, today CRG represent the most northern and western distribution of all gorillas and are isolated from Western lowland gorilla populations by more than 250 km. CRG have proved challenging to study and protect, and many of the remaining subpopulations currently exist outside of protected areas. Very little is known about where the various subpopulations range on the landscape or why they occur in a patchy distribution within seemingly intact habitat. Active efforts are currently underway to identify critical habitat for landscape conservation efforts to protect the CRG in this biodiversity hotspot but, to date, a lack of understanding of the relationship between CRG ecology and available habitat has hampered conservation endeavors. This dissertation aims to improve our understanding of CRG ecology and distribution to inform conservation management decision making. This research has four main components. First, I describe the plant diet of one CRG subpopulation (the Mone subpopulation). Successful habitat management for primate conservation requires understanding which plants are important and how these plants vary in availability across the landscape. Using feeding trail sign collected over a 10 month period, I record the components of the CRG diet, evaluate CRG selectivity among herbaceous food species, compare Mone CRG diet to that of another CRG subpopulation, and examine differences in herbaceous food availability in areas used and unused by the CRG. During the study period, the CRG ate 141 different plant parts from 102 different species, 23 of which were quantitatively important in the diet. Similarly to other Western lowland and CRG populations, Landolphia, Aframomum, and Palisota spp, were important staple species for the Mone CRG and Marantochloa purpurea played an important fallback role in their diet. By contrast, Araceae species, like Cercestis camerunensis, may be more important to the CRG at Mone than elsewhere. My results suggest that CRG in the Mone-Mt. Oko region prefer certain foods in their diet, and may also selectively use areas with higher availability of preferred foods. Second, I estimate the Mone subpopulation range and assess both the effects of model choice on resulting range estimates and the conservation utility of various models. Measuring and characterizing the area utilized by a population or species is essential for evaluation of conservation status and for effective allocation of habitat to ensure population persistence. Models considered in this study range from basic traditional approaches (e.g. Minimum Convex Polygon) to newer home range techniques such as Local Convex Hull (LoCoH). I used overlap analysis comparing sub-sampled to complete data sets to evaluate the robustness of various modeling techniques to data limitations. I employed Likelihood Cross Validation Criterion to compare core range model performance. Results suggest that differing LoCoH models produce similar range estimates, are robust to data requirements, provide a good fit for core habitat estimation, and are best able to detect unused habitat within the subpopulation range. LoCoH methods may thus be useful for studies of habitat selection and factors limiting endangered species distributions. However, LoCoH models tend to overfit data, and Kernel methods may provide similar information about animal space use while supporting protection of larger swaths of critical habitat. Subpopulation range analyses for conservation/management planning should therefore explore multiple modeling techniques, and employ both qualitative and quantitative assessments to select the best models to inform decision making for species of conservation concern.Third, I review current use of Least Cost Path modeling techniques for connectivity conservation, and highlight both weaknesses and ways to improve application for species like the Cross River gorilla. Promoting connectivity between areas utilized by isolated subpopulations is essential to maintain population viability in fragmented species like the CRG, where each subpopulation contains relatively few individuals. The most common approach to connectivity design is the Least Cost Path (LCP) analysis, which has been applied to the CRG landscape. This review highlights three weaknesses common in recent LCP analyses. First, LCP models typically rely on remotely-sensed habitat maps, but few studies assess whether such maps are suitable proxies for factors affecting animal movement or consider the effects of adjacent habitats. Secondly, many studies use expert opinion to assign costs associated with landscape features, yet few validate these costs with empirical data or assess model sensitivity to errors in cost assignment. Thirdly, studies that consider multiple, alternative movement paths often propose width or length requirements for linkages without justification. LCP modelling and similar approaches to linkage design guide connectivity planning, yet often lack a biological or empirical foundation. Ecologists must clarify the biological processes on which resistance values are based, explicitly justify cost schemes and scale (grain) of analysis, evaluate the effects of landscape context and sensitivity to cost schemes, and strive to optimize cost schemes with empirical data. Research relating species' fine-grain habitat use to movement across broad extents is desperately needed, as are methods to determine biologically relevant length and width restrictions for linkages. While data on such fine grain habitat use have to date been lacking for the Cross River gorilla, this dissertation research aims to improve our understanding of these variables.Thus, finally, I use hierarchical resource selection functions (RSFs) to examine habitat selection and requirements of the CRG at multiple scales to inform connectivity modeling and conservation planning. Specifically, I employ generalized additive models at the scale of the subpopulation range and conditional logistic regression at the scale of individual movements. Understanding resource and habitat selection by endangered species will better inform conservation planning for protection of both critical habitat, and essential linkages between subpopulations. Results indicate that CRG habitat selection is highly scale dependent. Localized measures of habitat quality strongly influenced selection at the subpopulation or landscape scale, while human activity and food availability are the best predictors of selection at finer scales. Understanding why CRG do not occur in seemingly suitable habitat is crucial for designating critical habitat both within and between CRG subpopulations. My results indicate that conservation planning to maintain critical habitat and connectivity among CRG populations will require an integrative, multi-scale planning approach incorporating large-scale landscape characteristics, human use patterns and CRG food availability. Further fine-scale data collection across the landscape will be necessary to use RSF results in connectivity models to inform conservation of important linkages between subpopulations.This research marks a significant addition to the current limited knowledge about the CRG dietary and spatial ecology and conservation biology. My study results complement past and ongoing research by other PhD students, conservation NGOs, and government officials, and compiling these various works will likely provide us with a more complete understanding of CRG ecology for effective conservation decision making
Twenty-one feral cats were radio-tracked using direct sighting and triangulation techniques (amassing 730 location fixes) during winter in an agricultural landscape in central-western New South Wales. Factors affecting home-range size, home-range overlap and habitat use were assessed. Mean home-range size was 248 ha (s.e. = 34.9, n = 15 cats, 598 location fixes). Home-range size and habitat use were not influenced by sex or age of adult cats, prey abundance or time of day. However, cat weight significantly influenced range size, with heavier cats having larger ranges than smaller cats. Although the cats are apparently solitary, their home ranges overlapped considerably, particularly between young adults and old adult cats. Cats were active both by day and night and did not occupy permanent dens. Home ranges encompassed mixed habitat types that provided both shelter and prey. Open woodland and open forest were the main habitat types covered by home ranges, but within these areas cats showed a preference for grassland, where rabbits were more abundant. The results recorded in this study indicate that cat-control programs should concentrate in mixed habitat areas, where both shelter and food are available, and over widely dispersed areas. The absence of group living suggests that the effectiveness of virally vectored fertility or biological control agents would be limited.
Context The number of teats that a female agile antechinus (Antechinus agilis) possesses effectively determines her initial litter size. In the Otway Ranges, south-eastern Australia, numerous separate populations in which all females have either six or 10 teats occur fairly close together in similar, contiguous forest at comparable altitudes and latitudes. Six-teat and 10-teat females have a similar mean mass, but the latter have a 1.7 × greater reproductive potential and so should have a greater nutritional requirement while raising young than do six-teat females. Theoretically, they could meet this requirement by occupying larger and/or more exclusive home ranges during breeding than do six-teat females do (provided that their food-resource abundance is comparable), albeit at a greater energetic cost. Aims The aim of the study was to determine whether 10-teat A. agilis females occupied larger and less overlapping home ranges than did six-teat females. To interpret the findings more meaningfully, it was necessary to compare food abundance and habitat characteristics in areas occupied by the two phenotypes. Methods The investigation was conducted in six-teat and 10-teat A. agilis areas in cool temperate forest over 22 months. Population density was determined by mark–recapture methods and arthropod prey biomass and abundance by pitfall trapping. Vegetation structure and plant-taxa abundance and diversity were determined by standard plant-survey methods. Female home-range estimates determined by radio-tracking were based on 95% minimal convex polygons (MCP) and kernel analysis. Home-range overlap was based on 80% MCP range determinations and core areas were calculated from utilisation plots. Key results Female population density was 2.5 × lower in exclusively 10-teat than in exclusively six-teat populations. Radio-tracked 10-teat females' home ranges less commonly overlapped those of identified female neighbours and, on average, were 1.5 × larger than ranges of six-teat females. Food abundance and composition was similar in six-teat and 10-teat areas, but ground cover was denser and more complex in the latter areas. Conclusions Food-resource availability was similar in the six-teat and 10-teat phenotype areas, so the larger, and probably more exclusive, home ranges of 10-teat females could reflect greater nutritional requirements resulting from having larger litters, and account for their lower population density. Implications The A. agilis teat-number variation pattern in the Otways may be a rare, visible example of ongoing incipient speciation. This makes it of great scientific and conservation value and it is important to document how the phenomenon operates.
Between 1983 and 1986, various aspects of red fox spatial behaviour were studied in both rural and semi-urban environments in central Victoria. Using radio-telemetry, the short-term home ranges of three adult foxes (2 male, 1 female) in a pasture/woodland habitat were estimated to be of the order of 5-7 km2 each. In a semi-urban environment nearby, the home ranges of a further 3 adult animals (2 male, 1 female) were estimated to be 0.6-1.3 km2 each. Estimates of home range size based on a 90% space utilisation effectively halved the home range area for all six foxes. There were indications that, for the animals concerned, ranges were mutually exclusive except in the case of a breeding pair which shared a common home range. During the studies, 137 young fox cubs were ear-tagged and released at the point of capture. Subsequently, 46 of these animals were returned by hunters. Nearly 70% of the returned animals were killed at a distance of 2 km or less from the tagging site but dispersal distances of up to 30 km were recorded. The average dispersal distance for animals killed more than 2 km from the tagging site was 11 km. Estimates of fox density in a rural area of some 2400 ha were obtained by a survey of active breeding dens in the 1985 and 1986 breeding seasons. Assuming one breeding pair plus three surviving young per litter, the maximum summer density was estimated at about 3.0 foxes km-2 and the minimum winter density as about 1.2 foxes km-2. For a further estimate of density, 13 foxes were live-captured, fitted with radios and released. In a short control program on the study area a few weeks later, 7 of these animals were recovered in a total sample of 50 foxes killed. The remaining 6 foxes were established as still present in the study area. Using this capturehecapture data, an early autumn density of about 3.9 foxes km-2 was indicated. The significance of this data in relation to the possible role of foxes as vectors of rabies disease in Australia is discussed.
The common brushtail possum (Trichosurus vulpecula) is an arboreal marsupial that has adapted well to urban landscapes. Fifteen adult possums (12 female, 3 male) caught in small patches of indigenous vegetation (remnants) in the south-east of metropolitan Melbourne were radio-tracked over a three-month period to investigate nocturnal behaviour and den use. Minimum convex polygon (100%) home-range estimates of both female (1.02 ± 0.28 ha) and male (1.19 ± 0.33 ha) urban brushtail possums trapped in urban forest remnants appear to be smaller than those previously reported for urban brushtail possums. All the brushtail possums foraged extensively in remnants but made repeated forays into adjacent residential areas. The use of few dens, by both female (2.21 ± 0.35 ha) and male (2.51 ± 1.45 ha) brushtail possums, in close proximity to their nocturnal ranges is similar to the behaviour of non-urban brushtail possums
The movements of two subspecies of the sand goanna, V. gouldii, were studied at two localities in South Australia. The estimated home ranges of individuals of V.g. rosenbergi differed considerably, the largest area being 25 times the size of the smallest. Daily activity areas varied with the season, being largest in summer and smallest in winter. There were distinct differences between the two subspecies in their activity patterns, V. g. rosenbergi being active throughout the year whereas Kg. gouldii remained underground during winter.
This paper was accepted for publication in International Journal of Ventilation in Aug 2016, and published online in Nov 2016. ; This work was also funded and supported by the European Union's Seventh Programme for research, technological development and demonstration under grant agreement No 314283. ['HERB': www.euroretrofit.com/]; and the Innovate UK programme for 'Scaling Up Retrofit' under project No: 101609. ['PULSE': www.pulseairtest.com/]
Context Understanding habitat selection is important for determining conservation and management strategies for endangered species. The Carolina northern flying squirrel (CNFS; Glaucomys sabrinus coloratus) is an endangered subspecies found in the high-elevation montane forests of the southern Appalachians, USA. The primary use of nest boxes to monitor CNFS has provided biased information on habitat use for this subspecies, as nest boxes are typically placed in suitable denning habitat. Aims We conducted a radio-telemetry study on CNFS to determine home range, den site selection and habitat use at multiple spatial scales. Methods We radio-collared 21 CNFS in 2012 and 2014–15. We tracked squirrels to diurnal den sites and during night-time activity. Key results The MCP (minimum convex polygon) home range at 95% for males was 5.2±1.2ha and for females was 4.0±0.7. The BRB (biased random bridge) home range at 95% for males was 10.8±3.8ha and for females was 8.3±2.1. Den site (n=81) selection occurred more frequently in montane conifer dominate forests (81.4%) vs northern hardwood forests or conifer–northern hardwood forests (9.9% and 8.7%, respectively). We assessed habitat selection using Euclidean distance-based analysis at the 2nd order and 3rd order scale. We found that squirrels were non-randomly selecting for habitat at both 2nd and 3rd order scales. Conclusions At both spatial scales, CNFS preferentially selected for montane conifer forests more than expected based on availability on the landscape. Squirrels selected neither for nor against northern hardwood forests, regardless of availability on the landscape. Additionally, CNFS denned in montane conifer forests more than other habitat types. Implications Our results highlight the importance of montane conifer to CNFS in the southern Appalachians. Management and restoration activities that increase the quality, connectivity and extent of this naturally rare forest type may be important for long-term conservation of this subspecies, especially with the impending threat of anthropogenic climate change.
