Environmental Protection
Living Resources
Biodiversity
In essence, biodiversity (biological diversity) is the full array of life on Earth. Yet biodiversity is more than just the number and diversity of species. The concept also includes the genetic variation within a given species of plant or animal. At a higher level, it includes the natural communities, ecosystems, and landscapes of which species are a part. The concept of biodiversity includes both the variety of these things and the variability found within and among them. Biodiversity also encompasses the processes � both ecological and evolutionary � that allow life on Earth to continue adapting and evolving. The Nature Conservancy describes three of the principal levels of biological organization as species, ecosystems, and landscapes.
Species diversity
Species diversity encompasses the variety of living organisms inhabiting an area. This is most commonly gauged by the number of different types of organisms � for instance, the number of different birds or plants in a state, region, or ecosystem. While this is the most easily grasped aspect of biodiversity for most people, it is actually populations or "bands" of species in a geographic area and their interactions that together are the focus of on-the-ground conservation efforts. By extension, this concept includes the interactions of "populations of populations."
Ecological diversity
Ecological diversity refers to the higher-level organization of different species into natural communities, and the interplay between these communities and the physical environment that forms ecosystems. Interactions are key to ecological diversity. This includes interactions among different species � predators and prey, for instance, or pollinators and flowers � as well as interaction among these species and the physical processes, such as nutrient cycling or periodic fires, that are essential to maintaining ecosystem function.
Landscape diversity
Landscape diversity refers to the geography of different ecosystems across a large area and the connections among them. Natural communities and ecosystems change across the landscape in response to environmental gradients such as climate, soils, moisture, or altitude and form characteristic mosaics. Understanding the patterns among these natural ecosystems and how they relate to other landscape features, such as farms, cities, and roads, is key to maintaining such regional diversity. There is an old saying amongst ecologists that "diversity breeds diversity."
Conservation of biodiversity requires attention to each of these levels, because all contribute to the persistence and variety of life on Earth. More than most people realize, humans rely on wild biological resources for food, shelter, medicine, and essential life processes.
Everything really is connected to everything else.
