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Large-herbivore distribution and abundance: Intra- and interspecific niche variation in the tropics

Ritchie, Euan G., Martin, Jennifer K., Krockenberger, Andrew K., Garnett, Stephen T. and Johnson, Christopher N. (2008). Large-herbivore distribution and abundance: Intra- and interspecific niche variation in the tropics. Ecological Monographs,78(1):105-122.

Document type: Journal Article
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Title Large-herbivore distribution and abundance: Intra- and interspecific niche variation in the tropics
Author Ritchie, Euan G.
Martin, Jennifer K.
Krockenberger, Andrew K.
Garnett, Stephen T.
Johnson, Christopher N.
Journal Name Ecological Monographs
Publication Date 2008
Volume Number 78
Issue Number 1
ISSN 0012-9615   (check CDU catalogue open catalogue search in new window)
Start Page 105
End Page 122
Total Pages 18
Place of Publication Washington, United States
Publisher Ecological Society of America
Field of Research 0406 - Physical Geography and Environmental Geoscience
0501 - Ecological Applications
0602 - Ecology
HERDC Category C1 - Journal Article (DEST)
Abstract Determining the biological and environmental factors that limit the distribution and abundance of organisms is central to our understanding of the niche concept and crucial for predicting how species may respond to large-scale environmental change, such as global warming. However, detailed ecological information for the majority of species has been collected only at a local scale, and insufficient consideration has been given to geographical variation in intraspecific niche requirements. To evaluate the influence of environmental and biological factors on patterns of species distribution and abundance, we conducted a detailed, broadscale study across the tropical savannas of northern Australia on the ecology of three large, sympatric marsupial herbivores (family Macropodidae): the antilopine wallaroo (Macropus antilopinus), common wallaroo (M. robustus), and eastern grey kangaroo (M. giganteus). Using information on species abundance, climate, fire history, habitat, and resource availability, we constructed species' habitat models varying from the level of the complete distribution to smaller regional areas. Multiple factors affected macropod abundance, and the importance of these factors was dependent on the spatial scale of analyses. Fire regimes, water availability, geology, and soil type and climate were most important at the large scale, whereas aspects of habitat structure and interspecific species abundance were important at smaller scales. The distribution and abundance of eastern grey kangaroos and common wallaroos were strongly influenced by climate. Our results suggest that interspecific competition between antilopine wallaroos and eastern grey kangaroos may occur. The antilopine wallaroo and eastern grey kangaroo (grazers) preferred more nutrient-rich soils than the common wallaroo (grazer/browser), which we relate to differences in feeding modes. The abundance of antilopine wallaroos was higher on sites that were burned, whereas the abundance of common wallaroos was higher on unburned sites. Future climate change predicted for Australia has the capacity to seriously affect the abundance and conservation of macropod species in tropical savannas. The results of our models suggest that, in particular, the effects of changing climatic conditions on fire regimes, habitat structure, and water availability may lead to species declines and marked changes in macropod communities.
Keywords Australia
climate change
conservation
fire
kangaroo
macroecology
Macropus
marsupial
species habitat model
sympatric niches
tropical savanna
wallaroo
DOI http://dx.doi.org/10.1890/06-2117.1   (check subscription with CDU E-Gateway service for CDU Staff and Students  check subscription with CDU E-Gateway in new window)


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