Treesearch

It is clear that grassland bird populations have declined significantly during the last 30 years. Declines are widespread in North America, making grassland birds a continental conservation priority. In New England and New York steep population declines for many species warranted listing in many states. Habitat loss through farm abandonment and the subsequent succession of grassland habitat to forest is the principle cause of the observed population declines. Because of the concern for grassland bird conservation and the lack of an understanding of the regional distribution and relative...

It is clear that grassland bird populations have declined significantly during the last 30 years. Declines are widespread in North America, making grassland birds a continental conservation priority. In New England and New York steep population declines for many species warranted listing in many states. Habitat loss through farm abandonment and the subsequent succession of grassland habitat to forest is the principle cause of the observed population declines. Because of the concern for grassland bird conservation and the lack of an understanding of the regional distribution and relative...

Grassland songbird populations have experienced some of the most severe declines of any migratory songbird guild in North America and are continuing to disappear from portions of their historic ranges. Habitat loss and degradation have been implicated as primary causes of these declines. However, intensive surface coal mining and subsequent reclamation in western Pennsylvania have created large tracts of grassland habitat during the past 30 to 40 years. We estimated the area of habitat suitable for breeding grassland songbirds on reclaimed strip mines in nine western counties of Pennsylvani...

We developed models to predict the potential response of wintering Neotropical migrant and resident bird species to alternative management scenarios, using data from point counts of birds along with habitat variables measured or estimated from remotely sensed data in a Geographic Information System. Expected numbers of occurrences at points were calculated for 100 species of birds, under current habitat conditions and under habitat conditions that would result from seven alternative management scenarios for Rancho Sandoval, a cattle ranch and private nature reserve in Campeche, México....

The majority of California Black Rails (Laterallus jamaicensis coturniculus; >90 percent) are found in the tidal salt marshes of the northern San Francisco Bay region, primarily in San Pablo and Suisun Bays (Manolis 1978, Evens et al. 1991). Smaller populations occur in San Francisco Bay, the Outer Coast of Marin County, freshwater marshes in the foothills of the Sierra Nevada, and in the Colorado River Area (Trulio and Evens 2000). Loss of more than 80 percent of historic tidal marsh habitat, as well as habitat fragmentation and degradation have directly and indirectly impacted this and...

Millions of Nearctic-Neotropical landbirds move through the coastal forests of the Gulf of Mexico each spring and autumn as they migrate across and around the gulf. Migration routes in the gulf region are not static—they shift year to year and season to season according to prevailing wind patterns. Given the dynamic nature of migration routes, coastal forests around the Gulf of Mexico potentially can provide important stopover habitat to en route migrants. The coastal forests from the Florida Keys to the Yucatan Peninsula include a wide range of habitat types that we have classified as 19...

Conservation planning for birds is increasingly focused on landscapes. However, little spatially explicit information is available to guide landscape-level conservation planning for many species of birds. We used georeferenced 1995 Breeding Bird Survey (BBS) data in conjunction with land-cover information to develop a spatially explicit habitat model predicting the occurrence of Northern Harrier (Circus cyaneus) in the Prairie Pothole Region of North Dakota, USA. Presence of Northern Harriers was positively associated with the amount of grassland in the landscape and presence of Northern...

In Canada, grassland conservation has been mobilized and directed through the development of Prairie Conservation Action Plans and Action Plan Committees in the three prairie provinces of Alberta (45 partner agencies and organizations), Saskatchewan (26 partners), and Manitoba (26 partners). In Alberta, 43 percent of the native prairie remains; in Saskatchewan and Manitoba the amount of mixed-grass prairie remaining is less than 20 percent, while tall-grass prairie in Manitoba has been reduced to less than one percent. Although there are many similarities in the approaches taken to...

Research at Caspar Creek provides information that helps forest managers assess and predict the environmental effects of forest practices and natural disturbances on downstream resources. Monitoring long-term effects and adapting practices can help protect and restore water quality and fish habitat in Northern California.

Ponderosa pine is a wide-ranging conifer occurring throughout the United States, southern Canada, and northern Mexico. Since the 1800s, ponderosa pine forests have fueled the economies of the West. In western North America, ponderosa pine grows predominantly in the moist and dry forests. In the Black Hills of South Dakota and the southern portion of its range, the species primarily occupies ponderosa pine potential vegetation types (PVTs) but, in the northern portion of its range, it grows on Douglas-fir, grand fir and/or white fir and western redcedar PVTs. Within this wide range of...