Birds as Indicators of Riparian Vegetation Condition in the Western U.S.
Wetlands and riparian areas comprise <1% of the land area in the western U.S., yet they support a tremendous diversity and abundance of wildlife. For example, in Arizona and New Mexico, at least 80% of all animals use riparian areas at some stage of their lives. In the Interior Columbia River Basin, 64% of neotropical migratory landbirds depend on riparian vegetation during the breeding season. This habitat may harbor from 2-10 times as many individual birds as does adjacent, non-riparian, vegetation.
Monitoring the health of riparian ecosystems involves the measurement of several different variables. For example, channel characteristics and vegetation age-class distribution are currently evaluated under the Proper Functioning Condition process (TR 1737-9, BLM, 1993). Additional monitoring to assess the occurrence of riparian obligate or dependent bird species will provide a fuller picture of ecosystem health. Experience on the San Pedro River in Arizona shows that the Common Yellowthroat and Song Sparrow, among other species, are excellent indicators of ecosystem recovery following the cessation of livestock grazing (see graph).
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| Populations of five riparian obligate species increased dramatically on the San Pedro River in Arizona following the complete removal of livestock. |
Those monitoring riparian systems can readily learn the distinctive songs of species that should be present and thereby help assess the health of riparian vegetation. Some good indicators, such as the Song Sparrow, are widespread and still reasonably common. Others, such as the Willow Flycatcher, require conservation action now to prevent further losses of habitat and population numbers (see table).
Although a large number of bird species use riparian vegetation at some time during the year, it is possible to define two sub-groups of landbird species that are especially reliant on riparian habitats during the breeding season.
This resource is based on the following source:
Bureau of Land Management. No date. Birds as indicators of riparian vegetation
condition in the western U.S. Bureau of Land Management, Partners in Flight,
Boise, Idaho. BLM/ID/PT-98/004+6635. Unpaginated.
This resource should be cited as:
Bureau of Land Management. No date. Birds as indicators of riparian vegetation
condition in the western U.S. Bureau of Land Management, Partners in Flight,
Boise, Idaho. BLM/ID/PT-98/004+6635. Jamestown, ND:
Northern Prairie Wildlife Research Center Online.
http://www.npwrc.usgs.gov/resource/birds/ripveg/index.htm
(Version 15DEC98).
Table of Contents
Tables and Figures
- Table 1 -- Riparian Obligate Bird Species
- Table 2 -- Riparian Dependent Bird Species
- Map -- The Western Working Group of Partners in Flight has defined six general geographic regions with inherent commonalities in the occurrence of riparian bird species. These correspond with groups of physiographic areas defined for the Breeding Bird Survey
- Graph -- Populations of five riparian obligate species increased dramatically on the San Pedro River in Arizona following the complete removal of livestock.
For further information, contact: Nongame Program Manager, Bureau of Land Management, 1387 S. Vinnell Way, Boise, Idaho 83703, 208-373-4043, or your Partners in Flight State Working Group Chair.
Installation: Extract all files and open index.htm in a web browser.ripveg.zip ( 52K) -- Birds as Indicators of Riparian Vegetation Condition in the Western U.S.
