Wittmer et al. 2007 (caribou) - Journal of Animal Ecology.pdf (295.06 kB)

Changes in landscape composition influence the decline of a threatened woodland caribou population

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journal contribution
posted on 18.09.2020 by Heiko Wittmer, B McLellan, R Serrouya, C Apps
Large-scale habitat loss is frequently identified with loss of biodiversity, but examples of the direct effect of habitat alterations on changes in vital rates remain rare. Quantifying and understanding the relationship between habitat composition and changes in vital rates, however, is essential for the development of effective conservation strategies. It has been suggested that the decline of woodland caribou Rangifer tarandus caribou populations in North America is precipitated by timber harvesting that creates landscapes of early seral forests. Such habitat changes have altered the predator-prey system resulting in asymmetric predation, where predators are maintained by alternative prey (i.e. apparent competition). However, a direct link between habitat condition and caribou population declines has not been documented. We estimated survival probabilities for the threatened arboreal lichen-feeding ecotype of woodland caribou in British Columbia, Canada, at two different spatial scales. At the broader scale, observed variation in adult female survival rates among 10 distinct populations (range = 0.67-0.93) was best explained by variation in the amount of early seral stands within population ranges and population density. At the finer scale, home ranges of caribou killed by predators had lower proportions of old forest and more mid-aged forest as compared with multi-annual home ranges where caribou were alive. These results are consistent with predictions from the apparent competition hypothesis and quantify direct fitness consequences for caribou following habitat alterations. We conclude that apparent competition can cause rapid population declines and even extinction where changes in species composition occur following large scale habitat change. © 2007 The Authors. Journal compilation © 2007 British Ecological Society.

History

Preferred citation

Wittmer, H., McLellan, B., Serrouya, R. & Apps, C. (2007). Changes in landscape composition influence the decline of a threatened woodland caribou population. Journal of Animal Ecology, 76(3), 568-579. https://doi.org/10.1111/j.1365-2656.2007.01220.x

Journal title

Journal of Animal Ecology

Volume

76

Issue

3

Publication date

01/01/2007

Pagination

568-579

Publisher

Wiley

Publication status

Published

Contribution type

Article

ISSN

0021-8790

eISSN

1365-2656

Language

en

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