An endemic organism is one that is found only within a certain region. There is a rush that goes along with seeing a species that can be found nowhere else. Georgia is actually home to a handful of endemic species, most of which are aquatic. The Altamaha Spinymussel (Elliptio spinosa) is a freshwater mussel only found in 3 river systems in Georgia. Freshwater mussels are actually the most imperiled group of organisms in North America. There are a large number of reasons why this could be but one thing is for sure, mussels are dying in large numbers. To give you an idea of how rare some species can be, when I worked in a mussel lab we would actually pit tag some species so that we would be able to find them later. In the time span of less than a year, our most productive mussel bed had completely died. For the Altamaha spinymuseel, it is estimated that populations have declined 50-70 percent and it only occurred in 7 sites out of 120 sites that were sampled after 2000. Few juveniles or small individuals were found in these surveys. It used to be found in the Ohoopee River system and Oconee River in addition to the Altamaha River system. In the Ohoopee and Oconee, the mussel is thought to be extirpated or populations are so small it is undetectable. All freshwater mussels, expect the Salamander mussel (Simpsonaias ambigua), have a stage in their life-cycle in which they are fish parasites. The glochidia, or baby mussels, attach to fish gills and develop there until they become juveniles. This is how they expand their range.
The Etowah darter (Etheostoma etowahae) is another species that is only found in the Peachtree state. It is a small fish that is about 2 inches long. The fish occurs a less than 10 locations in the Etowah River system. They prefer swift riffle habitats that have either cobble or gravel. There is likely less than 10,000 adults and at sites sampled the darter represents only a small part of the community. Because of this and the expansion of metro Atlanta into its habitat, the species is protected as an endangered species both federally and at the state level. They look very similar to the closely related greenbreast darter (Etheostoma jordani) and lipstick darter (Etheostoma chuckwachatte). Some scientists say that the Etowah darter and greenbreast darter differ by the red markings the Etowah darter has on its sides. This difference between species has been recently challenged with some saying you can’t tell the species apart without genetic testing. The Etowah darter does not co-occur with the lipstick darter so range maps can be used to determine which species you are looking at.
Stone Mountain is metro Atlanta’s most popular hiking spots. It also happens to be one of the 7 natural wonders of Georgia joining the ranks of; Amicalola Falls, Warm Springs, Okefenokee Swamp, Providence Canyon, Radium Springs and Tallulah Gorge. Stone Mountain is a giant igneous monolith that has a circumference of 5 miles at the base above ground but extends further underground. While it is very large it is not the largest piece of granite in the world, and some of the mountains is not composed entirely of granite, composition ranges from quartz monzonite to granite and granodiorite according to the Georgia Geological Survey Bullet. It is unclear what the largest piece of granite in the world is; I’ve heard the same claim from the Polar Caves in New Hampshire and from a rock in Yellowstone. It was formed from an upwelling of magma, about the same time that the Blue Ridge Mountains were formed.
There are many interesting species to observe at Stone Mountain as well. During the rainy season in the pools clam shrimp (Laevicaudata) and fairy shrimp (Anostraca) can be observed. Both of these are orders of small bivalves and crustaceans. The fairy shrimp is most commonly known as the sea monkey. Clam shrimps are very similar but they have a protective shell around the shrimp. They are both able to enter a state called diapause, in this state the eggs basically dry out and remain that way until it rains again. The eggs can even survive being out in space! Centuries later the eggs are still able to hatch. The species are not mobile unless they are aided by wind, bird’s feet, or currents. Fairy shrimp can well found on every single continent, including Antarctica.
Today I attended a lecture by Dr. Christopher Mowry who teaches at Berry College and founded the Atlanta Coyote project. The presentation opened with an image of a coyote (Canis latrans) standing inside Piedmont Park, which was taken in 2016. Coyotes belong to the Genus Canis, which is also home to the gray wolf (Canis lupus), red wolf (Canis rufus), and domestic dog (Canis lupus familiaris). While the gray wolf and coyote are agreed to be clearly separate species by experts, the red wolf has a lot of coyote genes. Both the red wolf and coyote are endemic to North America, meaning they are native and only found in that region. Sadly, the red wolf is now only found in the wild inside Alligator River National Wildlife Refuge in North Carolina.
Historically coyotes were a great plains species. They moved westward for two reasons in particular. The gray wolf is a natural predator of the gray wolf as is the red wolf. Due to the elimination of these predators the coyote was able to expand into new territory. But historically there was a region in which the gray wolf and coyote did live together, known as an admixture zone, where possible hybridization occurred. Urbanization also created an ideal habitat for the coyote, as it creates more edge habitat which increases their food supply of small mammals. For these regions, the coyote can now be found in every state, except for Hawaii.