Treesearch

The distribution of Brown-headed Cowbirds should reflect the distribution of their feeding (agricultural or grassy areas) and breeding (host) resources. Because an increase in one resource (e.g., agricultural areas) is often at the expense of the second resource (forest hosts), relationships between cowbird abundance, forest area, and number of hosts may reflect this trade-off. We studied cowbird distribution and abundance in the extensively forested Missouri Ozarks and fragmented central Missouri. Cowbirds were more abundant on fragments than on unfragmented Ozark study areas, even though...

Four bottomland tree species (green ash, bald cypress, water tupelo, and swamp chestnut oak) were planted under four levels of willow canopy (intact canopy, 60% thinned with herbicide, complete control with herbicide, and complete mechanical removal plus control with herbicide). Through age 5, species selection rather than canopy control treatment was the dominant factor in determining regeneration success. About 55% of the cypress and green ash seedlings were surviving at age 5, versus 17 and 27% of water tupelo and swamp chestnut oak, respectively. Green ash was significantly taller (at...

In 1996, the US-Canadian International Joint Commission identified five key stresses impacting the Great Lakes Basin Ecosystem: nutrient inputs (e.g., phosphorous and nitrogen), persistent toxic substances, physical alterations (e.g., sedimentation, infiltration, runoff, water levels), human activities and values (as manifested in land-use change, populations growth, urbanization, etc.), and exotic species. Michigan's Grand Traverse Bay Watershed (GTBW) is currently undergoing all of these problems as a result of rapid population growth and regional land-use change. In 1992, a Relative...

Established populations of the Asian longhorned beetle, Anoplophora glabeipennis, were first discovered in New York City in 1996 and then in Chicago in 1998. Because of the limited number and size of infestations discovered in 1996, the US Department of Agriculmre (USDA) initiated an eradication program that requires cutting and chipping of all infested trees. As of September 2000, more than 4800 infested trees have been cut in New York and more than 1400 in Chicago.

Ground beetles (Carabidae) are often used as bioindicators in land-use studies because they are (1) diverse, (2) abundant, (3) well known taxonomically, and (4) appear highly sensitive to habitat change. In 1996, we initiated a study on the Huron-Manistee National Forests in Newaygo County, Michigan, to document changes in the carabid community structure as a result of harvesting the overstory red pine stand on more than 140 acres. Prior to planting these sites with red pine seedlings in the 1940s, they were open dry sand prairies. Surrounding the harvested sites were natural stands of...

It is estimated that there are at least 4500 exotic (non-indigenous) organisms currently established in the United States(US) (US Congress 1993) and possibly as many as 50,000 (Pimentel et al. 2000). Of the many exotic organisms now in the US, more than 400 are insects that feed on trees and shrubs.(Haack and Byler 1993, Mattson et al. 1994, Niemela and Mattson 1996). Many of these exotic insects have severely impacted forest ecosystems throughout the US (Ciesla 1993, Liebhold et al. 1995, Morrell and Filip 1996, Wallner 1996, Mattson 1997).

Human economic and agricultural activities contribute to the endangerment of over 900 species that are currently listed or proposed for listing under the federal Endangered Species Act in the United States (Dobson et al. 1997). One approach to conserving the elements of biological diversity--including plants, animals, and ecological communities--is to establish and enhance biological reserves in which economic development is curtailed (Ando et al. 1998). For example, between 1927 and 1998, the U.S. Forest Service established 427 research natural areas (RNAs)coveting over 500,000 acres of...

When translocating individuals to found new populations, managers must allocate limited funds among release and monitoring activities that differ in method, cost, and probable result. In addition, managers are increasingly expected to justify the funding decisions they have made. Within the framework of decision analysis, we used robust optimization to formulate and solve different translocation problems in which both population growth and future funding were uncertain. Performance criteria included maximizing mean population size and minimizing the risk of undesirable population-size...

The Monarch Butterfly Project is a cooperative project between the Hiawatha National Forest of the US Forest Service and Wildlife Unlimited of Delta County, Michigan. In 1999, 58 volunteers contributed over 450 hours to monitor monarch reproduction and migation and to improve habitat for monarch butterflies near Penninsula Point, Delta County, in Michigan's upper peninsula.

Development of an assessment framework and associated indicators that can be used to evaluate the effectiveness of a wetland restoration is critical to demonstrating the sustainability of restored sites. Current wetland restoration assessment techniques such as the index of biotic integrity (IBI) or the hydrogeomorphic method (HGM) generally focus on either the biotic or abiotic components of wetlands. In addition, current methods generally rely on qualitative, or semi-quantitative rankings in the assessment. We propose a quantitative, ecosystem level assessment method similar to that...