Document Detail


An ecological comparison of the two arid-zone kangaroos of Australia, and their anomalous prosperity since the introduction of ruminant stock to their environment.
MedLine Citation:
PMID:  1221459     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This paper discusses the interactions between the large and medium-sized marsupials, the introduced ruminant domestic stock, and the environment in the arid zone of Australia. The grazing of sheep and cattle has produced suitable subclimax pastures which today favor two sympatric kangaroos but not the smaller bandicoots and wallabies. Tall grass tussocks used as shelter by the latter have been grazed down by the ruminants, and replaced by "marsupial lawns" or xeric spinifex, depending on locality, thereby improving the food supplies for the plains kangaroo and the hill kangaroo, respectively. It is argued, however, that even these smaller marsupials benefited originally from the new grazing regime. Patchy grazing of the grasslands probably created edge effects and other early seral changes which improved the food supplies while leaving adequate shelter. Continued grazing by increasingly large numbers of sheep and cattle ultimately and critically removed the shelter and, therefore, eliminated the bandicoots and wallabies. There is evidence that the plains kangaroo, though generally abundant at the present time, is vulnerable to competitive displacement by sheep, cattle, rabbits, and, in one region, by the hill kangaroo when it invades the plains. The plains kangaroo with its diet of green herbage is most threatened during droughts because the other herbivores have finer-grained diets. Like the bandicoots and wallabies the plains kangaroo in at least two localities appears to have first increased in numbers and then decreased. Sheep and cattle numbers have generally done the same. It is postulated, therefore, that there may not be two opposing response curves for the large and medium-sized marsupials to the ruminant invasion of the inland plains, but, in the long run, only one: an initial numerical increase and then decline. Only the time-scale is different, taking 50 years or more for the plains kangaroo, but perhaps half that time or less for the bandicoots and wallabies. The hill kangaroo may be the ultimate winner because it requires the least nitrogen, and the spinifex it eats during drought has spread as part of the subclimax created by ruminants.
Authors:
A E Newsome
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  The Quarterly review of biology     Volume:  50     ISSN:  0033-5770     ISO Abbreviation:  Q Rev Biol     Publication Date:  1975 Dec 
Date Detail:
Created Date:  1976-06-02     Completed Date:  1976-06-02     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0376515     Medline TA:  Q Rev Biol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  389-424     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Biological
Animals
Australia
Cattle / physiology
Diet
Ecology
Macropodidae / physiology*
Marsupialia / physiology*
Reproduction
Sheep / physiology
Water
Chemical
Reg. No./Substance:
7732-18-5/Water

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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