Document Detail

Understanding abundance patterns of a declining seabird: implications for monitoring.
MedLine Citation:
PMID:  18213960     Owner:  NLM     Status:  MEDLINE    
The Kittlitz's Murrelet (Brachyramphus brevirostris) is a rare, non-colonial seabird often associated with tidewater glaciers and a recent candidate for listing under the Endangered Species Act. We estimated abundance of Kittlitz's Murrelets across space and time from at-sea surveys along the coast of Alaska (USA) and then used these data to develop spatial models to describe abundance patterns and identify environmental factors affecting abundance. Over a five-week period in the summer of 2005, we recorded 794 Kittlitz's Murrelets, 16 Marbled Murrelets (B. marmoratus), and 70 unidentified murrelets. The overall population estimate (N, mean +/- SE) during the peak period (3-9 July) was 1317 +/- 294 birds, decreasing to 68 +/- 37 by the last survey period (31 July-6 August). Density of Kittlitz's Murrelets was highest in pelagic waters of Taan Fjord (18.6 +/- 7.8 birds/km2, mean +/- SE) during 10-16 July. Spatial models identified consistent "hotspots" of Kittlitz's Murrelets, including several small areas where high densities of murrelets were found throughout the survey period. Of the explanatory variables that we evaluated, tidal current strength influenced murrelet abundance most consistently, with higher abundance associated with strong tidal currents. Simulations based on the empirically derived estimates of variation demonstrated that spatial variation strongly influenced power to detect trend, although power changed little across the threefold difference in the coefficient of variation on detection probability. We include recommendations for monitoring Kittlitz's Murrelets (or other marine species) when there is a high degree of uncertainty about factors affecting abundance, especially spatial variability.
Michelle L Kissling; Mason Reid; Paul M Lukacs; Scott M Gende; Stephen B Lewis
Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Ecological applications : a publication of the Ecological Society of America     Volume:  17     ISSN:  1051-0761     ISO Abbreviation:  Ecol Appl     Publication Date:  2007 Dec 
Date Detail:
Created Date:  2008-01-24     Completed Date:  2008-02-20     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9889808     Medline TA:  Ecol Appl     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2164-74     Citation Subset:  IM    
U.S. Fish and Wildlife Service, 3000 Vintage Boulevard, Suite 201, Juneau, Alaska 99801, USA.
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MeSH Terms
Charadriiformes / physiology*
Conservation of Natural Resources
Environmental Monitoring
Population Dynamics
Time Factors

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

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