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Annual number of breeding pairs, fledged eaglets, and reproductive success increased during the study but below reproductive success of healthy bald eagle populations.
Voyageurs National Park (VOYA) in northern Minnesota contains significant aquatic resources including 30 lakes and numerous wetlands. This synthesis contains an integrated account of what is known about the aquatic resources of VOYA; compares VOYA resources to those of other areas; and identifies opportunities and needs for future studies and surveys. Surveys and studies in VOYA have identified fifty-four fish species from 16 families 820 vascular plant species and 7 amphibian and 3 reptile species (higher numbers probably occur). Estimates of relative abundance for phyto- and zooplankton vary among VOYA lakes and depths surveyed. The VOYA fish populations and communities have been the most intensively studied. Twenty-eight percent of VOYA wetlands are the result of beaver activity. Mercury contamination and its food-chain bioaccumulation in VOYA are of particular concern. An integrated monitoring plan is needed in VOYA to provide continuous data and information on the complex physical chemical, and biological factors that influence aquatic systems. Resource managers in VOYA will use this information to understand and explain observed changes and to predict the potential for future changes.
A variety of air pollutants are emitted into the atmosphere from human-caused and natural emissions sources throughout the United States and elsewhere. These contaminants impact sensitive natural resources in wilderness, including the national parks. The system of national parks in the United States is among our greatest assets. This book provides a compilation and synthesis of current scientific understanding regarding the causes and effects of these pollutants within national park lands. It describes pollutant emissions, deposition, and exposures; it identifies the critical (tipping point) loads of pollutant deposition at which adverse impacts are manifested.