The origins of the landscape stretch back a billion years, and the Great Smoky Mountains National Park is the most biologically diverse in the entire National Park system. The effects of the Park's history are what allows for the vast array of plant and animal species found in the Smokies, which are supported by its present rainy, temperate climate.
Great Smoky Mountains National Park is known to be the most biologically diverse in the entire National Park system. This biodiversity is in part a result of its past as a refuge for animals and plants migrating south away from glaciers. It can also be attributed to its mild, rainy climate. Scientists have identified 19,000 different species of plants and animals in the park and think that as many as 100,000 other species may have yet to be identified.
The vast majority of Great Smoky Mountains National Park is covered with forest—almost 95%. A quarter of that forest is considered old growth, which is a mature, mostly undisturbed forest with trees that are hundreds of years old. There are four different types of forest with the park: Spruce-fir forests, Northern Hardwood forests, Hemlock forests, and Pine-and-Oak forests. Spruce-fir forests are found at the highest elevations in the park some 4,500 feet above sea level and are a boreal forest. These forests are similar to those that can be found in Maine and Canada. Northern Hardwood forests are indicated by American beech, birch, and maple trees and grow mostly in the middle to upper elevations of the park. This is the forest type that creates the beautiful fall colors for which the Appalachians are famous. You can see the changing colors of the forests in seasonal images from the USGS/NASA Landsat program.
Hemlock forests grow in shady places often in almost pure stands. They are an ecologically important species, but unfortunately their existence is threatened by the hemlock woolly adelgid, a tiny non-native insect. Pine and oak forests grow best in the drier parts of the park where steep slopes allow the soil to drain quickly. Forest fires are an important of the natural system in this forest type.
Other ecosystems that can found within Great Smoky Mountains National Park include grassy and heath balds and wetlands. Balds are large meadows found in the middle and upper elevations of the park which support unique plant and animal types. Heath balds are composed of shrubby plants, and grassy balds are made up of grass and other shade-intolerant plants. Wetlands make up only a tiny part of the land area of Great Smoky Mountains National Park, but over 20% of the plant species found in the park are associated with these unique ecosystems. These wetlands support key ecological services including flood control, groundwater recharge, and prevention of stream erosion, among others.
Great Smoky Mountains National Park is home to more than 240 bird species, 67 native fish species, 65 different mammal species, and over 80 species of reptile and amphibians. Probably most notable among those mammal species, and the symbol of the park, is the black bear. There are about 1,500 black bears living in the park. These bears mostly eat berries and nuts with insects and animal carrion constituting a much smaller part of their diet. In the summer male black bears weigh on average about 250 pounds and female bears around 100, but in the fall, when bears are preparing for hibernation, bears over 600 pounds have been documented. Other mammal species of particular interest include elk and North river otters. Both species were recently reintroduced to the park after being wiped out. Before being reintroduced, elk had last been seen in the Southern Appalachians in the early 1800s.
Great Smoky Mountains National Park is a particularly important site for salamanders. In fact, the Great Smoky Mountains are known as the "Salamander Capital of the World.” Salamanders are lungless and “breathe” through tiny blood vessels in their skin. They are moist and slimy to the touch and most likely to be found along streams under rocks and leaves. One type of salamander found in the park, the Hellbender, can grow to 29 inches in length. Research done by USGS scientists plays an important role in the protecting and understanding these species.
The same streams that provide habitat for the park’s salamanders are also home to a number of fish species including lampreys, darters, shiners, minnows, suckers, bass, and trout. Fish and other aquatic animals are particularly vulnerable to environmental changes and degradation. There are already four federally-protected fish species in the park: the spotfin chub (threatened), duskytail darter (endangered), smoky madtom (endangered), and yellowfin madtom (threatened). USGS scientists in collaboration with National Park Service staff are currently working on a project to better understand the effect of high levels of acid deposition resulting from atmospheric emissions of nitrogen and sulfur oxides on vulnerable aquatic species.
Great Smoky Mountains National Park also supports over 240 species of birds, with new species being documented as recently as 2017. The variety of forest types and ecosystems within the park provide refuge for a diversity of bird types including a number of migratory species. More than a 100 bird species use the park as a breeding ground including species migrating from the neotropics and northern climes. The Smokies are the southernmost nesting limit for a number of northern birds, and the northernmost nesting limit for many southern birds. A study by USGS researchers in 2005 examined the differences in bird populations between the park’s old growth and secondary forests.
The diversity of plant life and rich ecosystems in Great Smoky Mountains National Park would not be possible without its pollinators. These include bees, beetles, ants, flies, wasps, butterflies, and moths. The USGS Native Bee Inventory and Monitoring Lab surveys and identifies native bees like those found in Great Smoky Mountains National Park. More than 4,000 Ultra Hi-Res public domain images of these amazing insects are available!