Dataset Identification:
Resource Abstract:
- description: The White-faced Ibis (Plegadis chihi) in the Great Basin and surrounding area was listed as a Species of Management
Concern (Sharp 1985, USFWS 1995) based on its small population size and vulnerability to breeding habitat loss. Traditionally,
most Great Basin ibises have bred in Utah and Nevada with peripheral but growing colonies in Idaho, California, and Oregon
(Sharp 1985, Ryder and Manry 1994). After apparently declining precipitously in the 1960's and 1970's (Capen 1977),
the Great Basin population was estimated at only 7,500 breeding pairs in 1984 (Sharp 1985). In addition to the Great Basin
population (as defined here), small numbers of ibises breed locally in Colorado, Wyoming, Montana, North and South Dakota,
and southern Alberta, and large numbers breed in Louisiana, Texas, Mexico, and South America (reviewed in Ryder and Manry
1994). Interchange among these sites and Great Basin colonies has not been investigated. In the arid Great Basin region, ibises
breed in semi-permanent wetlands which are susceptible to naturally occurring droughts and floods. Local population fluctuations
and colony abandonment reflect this vulnerability. The highly nomadic White-faced Ibis apparently compensates for wetland
dynamics by moving among breeding colonies and colonizing new wetlands within and between years (e.g., Ryder 1967, Capen 1977,
Ivey et al. 1988, Henny and Herron 1989). The nomadic nature of the White-faced Ibis, like that of several other colonial
ciconiiforms, suggests that conservation efforts be undertaken at the landscape level and that population dynamics, distribution,
and trends be monitored at the regional or population scale (e.g., Frederick et al. 1996). The status of the Great Basin breeding
population has not been reviewed since 1984 (Sharp 1985). Increases in breeding numbers in Oregon, Idaho, and California during
the 1980's and 1990's suggested either that ibises were increasing regionally or individuals displaced from flooded
Great Salt Lake marshes were colonizing elsewhere (e.g., Ivey et al. 1988, Follansbee and Mauser 1994, Trost and GersteIl1994).
An increase in wintering numbers also suggested a population increase (Shuford et al. 1989). Recognizing the need for a comprehensive
estimate of the breeding population, U.S. Fish and Wildlife Service (USFWS) coordinated a regional survey of all historic,
active, and probable colony sites in 1995. To further assess the 1985-1997 population trend, we compiled available annual
survey data for all known colonies. Here we report results of the 1995 survey and annual counts for 1985-1997. The objectives
of this report are as follows: I. Document changes in the distribution, abundance, and population trend of White-faced Ibis
breeding in the Great Basin and surrounding area during 1985-1997. 2. Interpret population-wide changes in ibis distribution
and abundance in relation to wetland dynamics throughout the region. 3. Discuss implications for future monitoring, research,
and conservation.; abstract: The White-faced Ibis (Plegadis chihi) in the Great Basin and surrounding area was listed as a
Species of Management Concern (Sharp 1985, USFWS 1995) based on its small population size and vulnerability to breeding habitat
loss. Traditionally, most Great Basin ibises have bred in Utah and Nevada with peripheral but growing colonies in Idaho, California,
and Oregon (Sharp 1985, Ryder and Manry 1994). After apparently declining precipitously in the 1960's and 1970's
(Capen 1977), the Great Basin population was estimated at only 7,500 breeding pairs in 1984 (Sharp 1985). In addition to the
Great Basin population (as defined here), small numbers of ibises breed locally in Colorado, Wyoming, Montana, North and South
Dakota, and southern Alberta, and large numbers breed in Louisiana, Texas, Mexico, and South America (reviewed in Ryder and
Manry 1994). Interchange among these sites and Great Basin colonies has not been investigated. In the arid Great Basin region,
ibises breed in semi-permanent wetlands which are susceptible to naturally occurring droughts and floods. Local population
fluctuations and colony abandonment reflect this vulnerability. The highly nomadic White-faced Ibis apparently compensates
for wetland dynamics by moving among breeding colonies and colonizing new wetlands within and between years (e.g., Ryder 1967,
Capen 1977, Ivey et al. 1988, Henny and Herron 1989). The nomadic nature of the White-faced Ibis, like that of several other
colonial ciconiiforms, suggests that conservation efforts be undertaken at the landscape level and that population dynamics,
distribution, and trends be monitored at the regional or population scale (e.g., Frederick et al. 1996). The status of the
Great Basin breeding population has not been reviewed since 1984 (Sharp 1985). Increases in breeding numbers in Oregon, Idaho,
and California during the 1980's and 1990's suggested either that ibises were increasing regionally or individuals
displaced from flooded Great Salt Lake marshes were colonizing elsewhere (e.g., Ivey et al. 1988, Follansbee and Mauser 1994,
Trost and GersteIl1994). An increase in wintering numbers also suggested a population increase (Shuford et al. 1989). Recognizing
the need for a comprehensive estimate of the breeding population, U.S. Fish and Wildlife Service (USFWS) coordinated a regional
survey of all historic, active, and probable colony sites in 1995. To further assess the 1985-1997 population trend, we compiled
available annual survey data for all known colonies. Here we report results of the 1995 survey and annual counts for 1985-1997.
The objectives of this report are as follows: I. Document changes in the distribution, abundance, and population trend of
White-faced Ibis breeding in the Great Basin and surrounding area during 1985-1997. 2. Interpret population-wide changes in
ibis distribution and abundance in relation to wetland dynamics throughout the region. 3. Discuss implications for future
monitoring, research, and conservation.
Citation
- Title White-faced Ibis in the Great Basin Area: A Population Trend Summary, 1985-1997.
-
- creation Date
2018-05-21T07:20:35.741568
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2018-08-07T00:11:32Z
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- notes: This metadata record was generated by an xslt transformation from a dc metadata record; Transform by Stephen M. Richard, based
on a transform by Damian Ulbricht. Run on 2018-08-07T00:11:32Z
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pointOfContact
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CINERGI Metadata catalog
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ISO 19139 Geographic Information - Metadata - Implementation Specification
standard version:
2007
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urn:dciso:metadataabout:2488b477-440e-4ff6-bb3a-6030ebc35f8f
Metadata record format is ISO19139 XML (MD_Metadata)