USDA provide vision to preserve our Nation's natural resources through conservation, restored forests, improved watersheds, and healthy private working lands.
A first choice for finding research articles in all areas of ecology and environmental studies. Web of Science provides access to the key ISI Citation databases Science Citation Index and Social Science Citation Index.
An interdisciplinary database that offers abstracts and citations to a wide range of research in biology, including zoology and ecology, and some aspects of agriculture and veterinary science.
GreenFILE offers well-researched but accessible information covering all aspects of human impact on the environment. Its collection of scholarly, government and general-interest titles include content on the environmental effects of individuals, corporations and local/national governments, and what can be done on each level to minimize negative impact. GreenFILE is multidisciplinary by nature and draws on the connections between the environment and a variety of disciplines such as agriculture, education, law, health and technology.
The Biodiversity Heritage Library works collaboratively to make biodiversity literature openly available to the world as part of a global biodiversity community. BHL also serves as the foundational literature component of the Encyclopedia of Life.
The Catalogue of Life is a comprehensive and authoritative global index of species with essential information on the names, relationships and distributions of over 1.5 million species.
From USGS, this site offers programs, databases, monitoring information and much more. If you are interested in the ramifications of invasive species, this is a good place to start.
Neotropical Birds Online is an authoritative, online resource for life histories of Neotropical birds.The scope of Neotropical Birds Online is all bird species that regularly occur in the Neotropics, from Mexico and the Caribbean south to southernmost South America. The emphasis is on species that breed within this region, but the eventual goal is to provide accounts for all species that regularly occur within this region.
Essentials of Conservation Biology by 
Key Topics in Conservation Biology 2 by