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Relationships between nutritional condition of adult females and relative carrying capacity for rocky mountain Elk

Rangeland Ecology and Management

By:
and
DOI: 10.2111/07-020.1

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Abstract

Lactation can have significant costs to individual and population-level productivity because of the high energetic demands it places on dams. Because the difference in condition between lactating and dry Rocky Mountain elk (Cervus elaphus nelsoni) cows tends to disappear as nutritional quality rises, the magnitude of that difference could be used to relate condition to habitat quality or the capability of habitats to support elk. We therefore compared nutritional condition of ???2.5-yr-old lactating and dry cows from six free-ranging RockyMountain elk populations throughout the United States.Our goal was to quantify differential accrual of body fat (BF) reserves to determine whether the condition of dry and lactating cows could be used to define relevant management thresholds of habitat quality (i.e., relative carrying capacity) and consequently potential performance of elk populations. Levels of BF that lactating cows were able to accrue in autumn and the proportional difference in BF between dry and lactating cows in autumn were related (F 1-2,10???16.2, P<0.001). Models indicated that elk experienced no negative effects of reproduction on condition when lactating cows were able to accrue ???13.7%BF in autumn.When lactating cows are accruing ???7.9%BF, elk are in a nutritionally stressed condition, which may be limiting population performance. Using the logistic model to predict relative proximity to ecological carrying capacity (ECC), our population-years ranged from3-97%ofECCand proportion of the population lactating (an index of calf survival) was negatively related to proportion of ECC. Results indicate that the proportional difference in accrual of BF between lactating and dry cows can provide a sensitive index to where elk populations reside relative to the quality of their range.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Relationships between nutritional condition of adult females and relative carrying capacity for rocky mountain Elk
Series title:
Rangeland Ecology and Management
DOI:
10.2111/07-020.1
Volume
62
Issue:
2
Year Published:
2009
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Rangeland Ecology and Management
First page:
145
Last page:
152
Number of Pages:
8