Using individual-condition measures to predict the long-term importance of habitat extent for population persistence

Cosgrove, Anita J., McWhorter, Todd J. and Maron, Martine (2017) Using individual-condition measures to predict the long-term importance of habitat extent for population persistence. Conservation Biology, 31 5: 1141-1151. doi:10.1111/cobi.12903

Author Cosgrove, Anita J.
McWhorter, Todd J.
Maron, Martine
Title Using individual-condition measures to predict the long-term importance of habitat extent for population persistence
Journal name Conservation Biology   Check publisher's open access policy
ISSN 1523-1739
Publication date 2017-10-01
Year available 2017
Sub-type Article (original research)
DOI 10.1111/cobi.12903
Open Access Status Not yet assessed
Volume 31
Issue 5
Start page 1141
End page 1151
Total pages 11
Place of publication Malden, MA, United States
Publisher Wiley-Blackwell Publishing
Language eng
Abstract Habitat loss and fragmentation are causing widespread population declines, but identifying how and when to intervene remains challenging. Predicting where extirpations are likely to occur and implementing management actions before losses result may be more cost-effective than trying to reestablish lost populations. Early indicators of pressure on populations could be used to make such predictions. Previous work conducted in 2009 and 2010 identified that the presence of Eastern Yellow Robins (Eopsaltria australis) in 42 sites in a fragmented region of eastern Australia was unrelated to woodland extent within 500 m of a site, but the robins’ heterophil:lymphocyte (H:L) ratios (an indicator of chronic stress) were elevated at sites with low levels of surrounding woodland. We resurveyed these 42 sites in 2013 and 2014 for robin presence to determine whether the H:L ratios obtained in 2009 and 2010 predicted the locations of extirpations and whether the previous pattern in H:L ratios was an early sign that woodland extent would become an important predictor of occupancy. We also surveyed for robins at 43 additional sites to determine whether current occupancy could be better predicted by landscape context at a larger scale, relevant to dispersal movements. At the original 42 sites, H:L ratios and extirpations were not related, although only 4 extirpations were observed. Woodland extent within 500 m had become a strong predictor of occupancy. Taken together, these results provide mixed evidence as to whether patterns of individual condition can reveal habitat relationships that become evident as local shifts in occupancy occur but that are not revealed by a single snapshot of species distribution. Across all 85 sites, woodland extent at scales relevant to dispersal (5 km) was not related to occurrence. We recommend that conservation actions focus on regenerating areas of habitat large enough to support robin territories rather than increasing connectivity within the landscape.
Keyword Birds
Brigalow Belt South
Chronic stress
Extinction debt
Habitat connectivity
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
School of Earth and Environmental Sciences
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Created: Tue, 19 Sep 2017, 08:20:21 EST by Anita Cosgrove on behalf of School of Earth and Environmental Sciences