Multiscale habitat selection of wetland birds in the northern Gulf Coast

Estuaries and Coasts
US Geological Survey; US Fish and Wildlife Service; Gulf Coast Joint Venture; Louisiana State University
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Abstract

The spatial scale of habitat selection has become a prominent concept in ecology, but has received less attention in coastal ecology. In coastal marshes, broad-scale marsh types are defined by vegetation composition over thousands of hectares, water-level management is applied over hundreds of hectares, and fine-scale habitat is depicted by tens of meters. Individually, these scales are known to affect wetland fauna, but studies have not examined all three spatial scales simultaneously. We investigated wetland bird habitat selection at the three scales and compared single- and multiscale models. From 2009 to 2011, we surveyed marsh birds (i.e., Rallidae, bitterns, grebes), shorebirds, and wading birds in fresh and intermediate (oligohaline) coastal marsh in Louisiana and Texas, USA. Within each year, six repeated surveys of wintering, resident, and migratory breeding birds were conducted at > 100 points (n = 304). The results revealed fine-scale factors, primarily water depth, were consistently better predictors than marsh type or management. However, 10 of 11 species had improved models with the three scales combined. Birds with a linear association with water depth were, correspondingly, most abundant with deeper fresh marsh and permanently impounded water. Conversely, intermediate marsh had a greater abundance of shallow water species, such as king rail Rallus elegans, least bittern Ixobrychus exilis, and sora Porzana carolina. These birds had quadratic relationships with water depth or no relationship. Overall, coastal birds were influenced by multiple scales corresponding with hydrological characteristics. The effects suggest the timing of drawdowns and interannual variability in spring water levels can greatly affect wetland bird abundance.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Multiscale habitat selection of wetland birds in the northern Gulf Coast
Series title Estuaries and Coasts
DOI 10.1007/s12237-013-9757-2
Volume 37
Issue 5
Year Published 2014
Language English
Publisher Estuarine Research Federation
Publisher location Port Republic, MD
Contributing office(s) Coop Res Unit Atlanta
Description 11 p.
First page 1301
Last page 1311
Online Only (Y/N) N
Additional Online Files (Y/N) N
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