By: Steve Roark
Volunteer, Cumberland Gap National Park

Biodiversity is a big deal in ecology science these days. The dictionary defines it simply as the variety of living things in a particular area or region. Opinions on the importance of biodiversity vary, but to me the loss of native plant or animal species means something’s wrong, and rightfully raises some concerns.

There are around 1.8 million species of life formerly documented by scientists, and some estimate the actual number could be much higher. The United States is blessed with the most temperate assembly of species in the world, more than 200,000. Of the 14 biomes (ecological regions) identified world wide, the US has representatives of all but two of them. This is no surprise, considering our country encompasses 3.5 million acres of space, outsized only by Canada, Russia, and China. The US is also geologically diverse, with peaks above 20,000 feet to valleys 200 feet below sea level. We have large rivers, small intermittent streams, hot deserts, cold deserts, Great Plains, Great Lakes, temperate (not too hot, not too cold) forests, tropical rain forests, coastal plains, basins and ranges, and alpine tundra. The secret to our lush diversity is a temperate climate that through overlap can support both cold and warm adapted species.

Here is a rough head count of species in the U.S. There are a lot of insects, nearly 100,000 species. Next are mushrooms and their relatives, weighing in at 34,000 species. There are 7,500 mollusks (clams and mussels) and 1400 mosses. There are 1,600 species of jellyfish and coral, 700 liverworts, and 375 sponges. Microscopic life forms are immense in number.

Ten percent of the world’s freshwater fish species are in the US, and half of all crayfish. We have 40% of Earth’s salamanders, 17% of the fresh water snails, 22% of the fresh water turtles, 15% of the coniferous trees (pine, spruce, hemlock), and 9% of the mammals.

The United States has six ecological hot spots that have a high number of rare species. One of them is the Southern Appalachians where we live, so it’s important to take care of what we have. Some threats to biodiversity include loss of habitat through converting wild land to something else. We have a huge problem with invading alien species, which out compete or kill native plants and animals. There are 4500 alien species that have a toehold in the US, and that number is growing fast. Pollution is another problem, impacting aquatic species the hardest. Other problems include overexploitation (we’re harvesting too many of them), and diseases (both foreign and native).