Using implanted radiotransmitters, we monitored body temperatures in five platypuses ranging freely in the Thredbo River in Australia's southern alps between April and October 1988, where the water gets as cold as any that a platypus is likely to encounter. Activity pattern showed a distinct daily cycle. No evidence of hibernation or even brief periods of torpor was found, all individuals maintaining body temperatures close to 32-degrees-C throughout the winter (mean+/-s.d., 32.08 +/- 0.75-degrees-C, range 29.2-34.6-degrees-C, n = 2237). No differences were found between the means or the variances of body temperatures of animals during day-time rest in stream-bank burrows and those during night-time foraging in winter at temperatures as low as 1.0-degrees-C.
This paper develops a hierarchical landscape approach for investigating how landscape structure influences the abundance of eastern grey kangaroos, red kangaroos and common wallaroos on properties in a partially cleared semi-arid woodland of Queensland. This approach is applied to examine the extent to which a mosaic of spatial factors at a hierarchy of scales influences kangaroo abundance at the property level. the level of management interest. The analysis concludes that the structure of the property habitat mosaic, coupled with pasture productivity, is the most important influence for each species. Access to water was not a limiting factor. although it may be important locally. Grey kangaroos prefer an even mosaic of all habitat types on properties with productive grass-dominated pastures. Red kangaroos are positively associated with run-on areas and large-shrub regrowth patches. reflecting their foraging preferences for forbs and short grasses and their ability to use more open habitats. Wallaroos have a clumped density distribution associated with a heterogeneous mosaic of open habitats interspersed with fragmented forest patches and small to medium-grained shrub-regrowth patches. The research. \+bile not replicated. identifies linkages between tree clearing practices at the property level and increased large kangaroo abundance in the region, These linkages have been previously overlooked in thc kangaroo Inanagement debare. Therefore. any tree clearing guidelines dt.\eloped at the propert) level need to be sensitive to key ecological processes influencing kangaroo populations at both the landscape and property levels. If not, the sustainable management of total grazing pressure (livestock plus kangaroos) and biodiversity conservation will never become a reality. Key words: kangaroos, landscape structure, landscape change, pattern, process, scale
As part of a large-scale monitoring program
linked to the management of kangaroos in the South Australian pastoral zone,
the western grey kangaroo populations have been surveyed annually with
fixed-wing aircraft over the 15-years-period 1978–92. Western grey
kangaroos are restricted in their distribution to the southern regions of the
pastoral zone. During the period of the study, western grey kangaroo numbers
showed no long-term trends, but did show some marked fluctuations, principally
in association with a severe drought. Despite this, and unlike red kangaroos
in the South Australian pastoral zone, no consistent, direct association
between changes in western grey kangaroo numbers and antecedent rainfall could
be demonstrated. The postulated reason for this is that most of the regional
western grey kangaroo populations examined in this study were low-density
populations at the edge of the range of this species. Outside of drought,
these populations are likely to be limited by factors other than food, such as
climate and unmodified resources in the form of suitable habitat. Also,
because boundary populations may well only be maintained by constant loss and
recolonisation, local extinctions associated with drought may result in
extended delays in the re-establishment of populations in marginal areas. Over
the period 1978–92, these populations were harvested commercially at
annual rates of 5–25%, which were, on the whole, considered to be
below the rates suggested to be maximum and sustainable.
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