If you spend any amount of time in the town of Wimberly, Texas locals will be sure to mention the flood that happened in 2015. 13 people died and 350 homes were destroyed. However, there was a silver lining to the flood, a large number of fossils, including dinosaur footprints were discovered in the Blanco River. These footprints were discovered when the City of Blanco GIS manager was reviewing aerial photographs. From the photographs, we can clearly see the footprints of a four-legged dinosaur (or sauropod). Based on the distance between the front feet, foot size, time at which the tracks where made, and stride length it’s like that the tracks belong to Paluxysaurus Jonesi, or as anyone who has watched the land before time would call it, a longneck. It’s actually the state dinosaur of Texas. The footprints are located on federal owned land that you can only access with a ranger and I’m not sure if the public can visit. I was able to visit through the master naturalist program. Here is a link to other dinosaur footprint site in Texas you can visit though.
There were a ton of other fossils the rangers pointed out to us as well. The most mind-blowing to me was a microfossil. At one point we were walking in some small gravel and the ranger told us to look down. Turns out we were actually walking on millions of microfossils of a former unicellular organism that lived in the ocean. The sheer number of them was astounding. The concept of microfossils is pretty crazy too. Researchers can actually find microfossils of plankton or pollen and learn a lot about what past environments where like.
The Georgia coast contains many unique habitats. Although the coastline is only 90 miles long it contains a third of all coastal wetlands on the East Coast. Most of these wetlands are found in the region referred to as the Golden Isles which are made up of Brunswick and its four barrier islands; St Simons Island, Jekyll Island, Sea Island and Little St Simons. These islands actually contain 28 percent of the coastal wetlands of the east coast of the united states. Jekyll Island in particular is owned by the State of Georgia, which has created zoning that allows 65 percent of the island to remain in a natural state. I have been fortunate enough to spend some time in this region and it is well worth the 4-hour drive from metro Atlanta to get there.
Driftwood beach on Jekyll Island is among the most well known in the region. Strong currents let to erosion which caused the trees to die, which were then preserved by the salt air. The in the southern part of the beach there are piles of large rocks. In these rocks, you can find sea squirts, blue mussels (Mytilus edulis), and some species of crabs. Be sure to visit the beach at low tide as the critters in these rocks can only be accessed at this time. In addition, as the tide rises most of the beach goes underwater and you will be forced to either walk back in the uplands or in the water. If you walk northward on the beach you can reach a bike path that runs through a salt marsh. If you continue north you will eventually end up in St Simons Sound. This marsh contains a lot of bird species, in fact, e-bird has reports of over 304 species here. If you don’t have an e-bird you can view birds that have been seen on the beach on this inaturalist page. This is in part due to the fact that the beach serves as a critical stop-over habitat for migrating shorebirds. Highlights include the threatened birds like thepiping plover (Charadrius melodus), wood stork (Mycteria americana), golden-winged warbler (Vermivora chrysoptera), red-cockaded woodpecker (Leuconotopicus borealis), black-capped petrel (Pterodroma hasitata) and Fea’s petrel (Pterodroma feae).
Okefenokee National Wildlife Refuge is located in South Georgia, near the border with Florida. Recently my friend and I visited to paddle around the swamp and drive around swamp island and walk the Chesser Island boardwalk to try and see some wildlife. The refuge is 630 square miles and encompasses nearly all of the swamp and was designated as a refuge in 1937 by President Roosevelt. It is one of the best preserved freshwater ecosystems in the world and some of the swamp is a national wilderness area. In the western part of the refuge there are is a cypress swamp but in the east it opens up to a prairie land. If you rent a kayak from Okefenokee adventures its is a short trip to see both regions of the swamp. The swamp is births the St. Marys river and the Suwannee river. Okefenokee is a native american word which means land of trembling earth. Most of the “solid” ground is actually peat that is floating. This floating peat is called batteries. Overtime the batteries grow larger and area able to support trees and large animals. The swamp was formed in a saucer shaped depression that used to be a part of the ocean floor.
Many people do not realize that fire plays an important role in the swamp. Without fire the swamp would simple become a hardwood forest. Today prescribed burns reduce the amount of fuel available fire fires. In areas where there is a natural fire regime and humans stop these fires there is a build up of organic materiel. When a fire does break out because there is more fuel, the fire burns hotter than it normally would, damaging the seed bank in the soil. This can permanently damage the ecosystem. One of the most recent fires in Okefenokee occurred in 2011 in the Honey Prairie which burned down the former boardwalk on Chester Island. This was not due to a build up of fuel however, as the parks service lets fires that were caused by lighting burn which maintaining the safety of people and structures inside the park. The new boardwalk has a built in sprinkler system. Over the 7,000 years that the swamp has existed fires occur an average of every 20 years. Currently the swamp is regenerating from the fire. Notable from the young pond cypress trees (Taxodium ascendens) that are sprouting. Trees that sprout from old stumps are common and actually grow faster than seed generated trees. This stump sprouts are called coppices.
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 (Etheostomajordani) 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.
Recently I had the joy of going birding with a local group in a small park in Brookhaven, Georgia. We saw over 33 species.
I was surprised that members of the group were excited to see double-crested cormorant (Phalacrocorax auritus). There is a common misconception about them that I have heard mostly due to the increase in their population, particularly on Lake Champlain in Vermont, where I grew up. When DDT was banned in 1972, it opened the door for the cormorant population to expand and it did. On Lake Champlain, the populations went from one breeding pair in 1981 to over 4,500 breeding pairs. Cormorants are piscivorous, meaning that they consume fish. Their population growth raised concerns with fisherman, one of which who told me that cormorants are an invasive species. To further this belief, the state of Vermont in 1999 began to oil the eggs of the birds. This prevents gas exchange and kills the birds in the eggs. The birds prefer to eat fish that are between 3 to 6 inches. On Lake Champlain, it has been shown that most of their diet is yellow perch (Perca flavescens) and alewives (Alosa pseudoharengus). Rarely are trout and salmon found in their stomachs, except when the fish are released annually into the lake from fish stocking facilities.
We also saw 17 tufted titmouse (Baeolophus bicolor), which I learned to identify by their classic peter-peter-peter call. They are year-round residents of this area and in most of the Eastern United States. They often flock with chickadees, nuthatches, and woodpeckers. Flocking means that predators are less likely to capture one as more birds are on the lookout for them. Food gathering efficiency is also increased by flocking behavior. In addition, there is reduced inter-species aggression which reduces competition. If you would like to attract tufted titmouse to your property they visit bird feeders and also benefit from nesting boxes. It is important to place a guard around nesting boxes to protect from predators and to place the boxes up well before breeding season.
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.