Influence of Landscape Structure on Kangaroo Abundance in a Disturbed Semi-Arid Woodland of Queensland.

Abstract

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

Movements of Marine Fish and Decapod Crustaceans: Process, Theory and Application

“…Furthermore, marine animals are likely to respond to and be constrained by the composition and spatial arrangement of resources in a hierarchical way, as has been suggested for many terrestrial animals (Senft et al, 1987;Schaefer and Messier, 1995;McAlpine et al, 1999;Rolstad et al, 2000). A single scale approach cannot incorporate important patterns and processes at scales above and below the focal scale and therefore this approach is limited in ecology.…”

“…Researchers that practice landscape ecology recognise that ecological patterns and processes operate at a range of scales in time and space and that many organisms respond to this hierarchically. This organism-based perspective means that 'habitat' and the relevant patterns and processes in the surrounding environment are defined and scaled by the activities and responses of the organisms of interest (Wiens, 1976;Harris, 1980;Addicott et al, 1987;Morris, 1987;Wiens and Milne, 1989;Kotliar and Wiens, 1990;Pearson et al, 1996;McAlpine et al, 1999).…”

“…In animal ecology, however, the process must also ensure that the chosen metrics capture all dimensions of spatial pattern relevant to an animal. For exploratory studies of the influence of mosaic pattern on animals, a suite of metrics is typically used (26 metrics by McGarigal and McComb (1995) for bird assemblages; 17 metrics by McAlpine et al (1999) for kangaroos and eight metrics by Hansen et al (2001) for caribou). For marine systems, however, this type of approach remains largely theoretical (Robbins and Bell, 1994), with few attempts to quantify spatial pattern (Garrabou et al, 1998 for rocky shores; Robbins and Bell, 2000 for seagrasses; Teixidó et al, 2002, for Antarctic benthic communities).…”

“…In addition, exploratory studies undertaken on a wide range of highly mobile animals including hoverflies (Haslett, 1994), birds (Pearson, 1993;McGarigal and McComb, 1995), kangaroos (McAlpine et al, 1999) and Florida panther (Kerkhoff et al, 2000) have recognised that investigation of a species response to spatial pattern must take place at multiple scales. These previous studies have quantified mosaic structure within a range of spatial extents, delineated around an observation area for a particular species or group of species.…”

“…In the Alps of southern Germany, Haslett (1994) quantified mosaic complexity by computing fractal dimensions within circles of 300 m radius that were estimated to have incorporated hoverfly home ranges. In Queensland, Australia, McAlpine et al (1999) quantified mosaic structure for kangaroos at a number of radial extents from 5 to 15 km surrounding each 10 km line transect. In Florida, USA, Kerkhoff et al (2000) quantified forest cover at multiple scales using fractal dimensions and assessed the association with known panther locations (telemetry) via conditional mapping.…”