What is Biodiversity? The United Nations Environmental Program's Convention on Biological Diversity uses the following definitions, which we will also use here: Biological diversity means the variability among living organisms from all sources including terrestrial, marine, and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species, and of ecosystems. Ecosystem means a dynamic complex of plant and animal communities and their non-living environment interacting as a unit. Habitat means the place or type of site where an organism or population naturally occurs. Protected area means a geographically defined area which is designated or regulated and managed to achieve specific conservation objectives. Sustainable use means the use of components of biological diversity in a way and at a rate that does not lead to the long-term decline of biological diversity, thereby maintaining its potential to meet the needs and aspirations of present and future generations. Ecosystem diversity refers to the variety of habitats and communities, as well as ecological processes driving those communities. This web of interaction is an essential aspect of the total diversity of a region. Humans, along with all other life on earth, depend on biodiversity for food, shelter, water, climate stability, temperature control, clean air and water, medicine, flood control, economic security, and natural beauty. Biodiversity describes the variety of living things and their relationships to each other and interactions with the environment. It's often easy to forget how important biodiversity is to our everyday life. But without forests, we would not see deer or chipmunks. Without clean rivers, there would be no fish. Without lakes, we couldn't take our children to feed the ducks. The Rutgers University Biodiversity Initiative defines biodiversity as "the sum total of all plants, animals (including humans), fungi and microorganisms, along with their individual variations and the interactions between them. It is the set of living organisms and their genetic basis that make up the fabric of the planet earth and allow it to function as it does, by capturing energy from the sun and using it to drive all of life's processes." There are three commonly used types of biodiversity: habitat diversity, genetic diversity, and species diversity. For the purposes of this website, we will focus on habitat diversity, because smart growth planning tools are generally used to reduce irresponsible land consumption, thereby preserving habitat. If habitats are areas where plants and animals interact with each other, habitat diversity refers to the variety of places where life exists. These habitats allow biodiversity to flourish, and when habitats disappear, so do the species that live in them. Forests, waterways, wetlands, and many other types of habitats provide homes for the plant and animal life that exists within them. Without an intact, unpolluted habitat, biodiversity is diminished. Habitats are compromised not only when they are completely eliminated with a bulldozer, but also when they are cut into small pieces, closed off from surrounding natural areas, or used irresponsibly. According to the Biodiversity Project, a non-profit biodiversity protection advocacy organization, biodiversity can be measured in four ways: Genetic variability within a species. Genetic differences are expressed through different sizes, colors, etc. Diversity of populations of a species. This is measured in both the number of individuals within a local group as well as the distribution of a species' geographic range. Diversity of species within a natural community. This refers to the variety of different species in a particular area. A wide array of natural communities and ecosystems throughout the world. The United States hosts a huge variety of life, providing habitat for more than 200,000 identified species and suspected of hosting another 200,000 not-yet-identified species. But there is a documented decline in the nation's flora and fauna, and it is estimated that one-third of U.S. species are at risk. More than 500 U.S. species are already extinct or missing, and nearly 60% of the U.S. mainland has lots its natural vegetation. Habitat loss it the leading threat to U.S. species.