Naturalist Fact: Orchard Spider

orchard spider 2

Orchard spiders are very common on Little St. Simons Island.  You can often see them in the maritime forest, but these successful spiders don’t just thrive in Georgia’s humid heat.  Orchard spiders have an extensive range from southern Canada to central America.  Orchard spiders (genus Leucauge) are in the family Tetragnathidae, which also includes the common long-jawed orb weavers (genus Tetragnatha).  Both the orchard spiders and the common long-jawed orb weavers are considered long-jawed orb weavers and are distinguished from true orb weaver spiders by their long chelicerae (fangs).  Like the true orb weaver spiders, orchard spiders create webs which are in the shape of a circular grid.  All spiders in the Tetragnathidae family have eight eyes, and typically do not exceed one inch across.  Male spiders are usually about half the size of the females.

Although orchard spiders are in the long-jawed orb weaver family, they more closely resemble true orb weaver spiders (family Araneidae) than the species in the common long-jawed orb weaver genus (Tetragnatha).  Orchard spiders usually build webs only a few feet from the ground, and most webs are horizontal in orientation.  The spiders are typically seen hanging upside-down in the middle of their webs while waiting for prey to land in the web.  Webs are built in strategic locations to catch flies, moths, and other insects.  Birds and other small animals may predate on orchard spiders.

Although there is some variation in coloration for each species of orchard spider, most have bright coloration on their abdomen, and many have dark green to black legs.  Leucauge venusta is the most easily identifiable orchard spider in our area.  This species is easily seen on Little St. Simons Island and usually have orange markings on the underside of their abdomen.  A hike on backbone trail on LSSI may produce many opportunities to observe these beautiful little creatures.  Although a small spider, they can usually be photographed with relative ease because they often remain quite still hanging on their web.

Cool Fact:  This species is parasitized by a wasp larva which attaches to the spider at the junction of the cephalothorax and the abdomen!

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Naturalist Fact: Manatee

Manatee (Trichechus manatus)

http://animalscamp.com/wp-content/uploads/2011/11/Florida-Manatee.jpg

From: http://animalscamp.com/wp-content/uploads/2011/11/Florida-Manatee.jpg

Manatees are large aquatic mammals found in warm coastal waters including tidal rivers and estuaries.  Often called “sea cows”, manatees are in fact more closely related to elephants than they are to cows.  Being entirely herbivorous, manatees will eat large amounts both saltwater and freshwater plants.  Manatees only have molars, which are used to grind up the plant matter they ingest.  In just one day a manatee may eat up to a tenth of its bodyweight, and they can be quite heavy.  Individuals are typically 8 to 13 feet in length and will weigh 440 to 1,300 pounds.  The average lifespan of manatees in the wild is 40 years.

 

Manatees prefer warm water, and tend to be found in regions where the water temperature is above 68 degrees Fahrenheit.  These gentle and slow-moving creatures will migrate north along the Atlantic coast during the warm summer months and can be found in the coastal waterways near Little St Simons Island throughout the summer.  Manatees spend most of their time resting and eating, but they can be playful as well.  Like all marine mammals, manatees must breathe air at the surface through nostrils, but can remain submerged for up to 15 minutes at a time.

 

Historically, manatees were often hunted for their hides, oil, and bones.  Being gentle and slow-moving made the manatee an easy target for hunters.  Today manatees are an endangered species, and they are protected by law.  Even with protection, manatees still face a number of threats including boat strikes and entanglement in fishing equipment.  On many individuals scars are visible where a wound from a boat has healed.

 

While it may be tempting to pet manatees or give them freshwater to bring them closer, these actions may negatively affect manatees.  Manatees may begin to associate humans or boats with these actions which can put them at higher risk for boat strikes.  If you do happen to have the exciting experience of seeing a manatee, the best thing to do is simply enjoy watching it interact with its natural environment.

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Horseshoe crab and shorebird bonanza!

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Horseshoe crabs gather in large groups at nesting beaches in the days surrounding full and new moons.

Having inhabited the oceans for over 350 million years, horseshoe crabs (Limulus polyphemus) are a glimpse into prehistory. We spot them most often as dead carcasses or molts along the shoreline. However, right now we are seeing hundreds of live, healthy, active crabs at the waterline.

Birders at Sancho Panza marvel at the horseshoe crab "arribada."

Birders at Sancho Panza marvel at the horseshoe crab “arribada.”

Horseshoe crabs spend most of the year in deeper waters, but in the late Spring they begin to move inshore to mate in large aggregations. Hundreds are gathering at Sancho Panza Beach here on Little St. Simons Island. Mating activity peaks around the full moon and new moon cycles, and with the full moon last week, we found big groups of males fighting for the chance to fertilize some eggs, and several indentations in the soft, wet sand where undoubtedly nests had been left behind.

A female will push several clumps of eggs down into the sand with specially adapted appendages. Each clump can contain two to four thousand eggs, and over the course of her spawning season, a female will deposit around 90,000 miniature eggs! Of those 90,000 eggs, only about 10 are expected to mature into adult horseshoe crabs.

If you are familiar with our island, you know that Sancho Panza is an excellent shorebirding spot, and right now we are in the peak of Spring migration. It is quite the spectacle to see a variety of shorebirds eating to their little hearts’ content at the buffet of horseshoe crab eggs! In fact, horseshoe crabs are instrumental in the journeys of at least 20 species of migratory shorebirds along the Eastern Seaboard.

Ruddy Turnstone feeding at a horseshoe crab nest. (Photo: Pete Oxford)

Ruddy Turnstone feeding at a horseshoe crab nest. (Photo: Pete Oxford)

Sanderling feeding on horseshoe crab eggs. (Photo: Pete Oxford)

Sanderling feeding on horseshoe crab eggs. (Photo: Pete Oxford)

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Naturalist Fact: Lichens

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Crustose lichen commonly found on Southern Magnolia trees on LSSI.

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Foliose lichen on a Southern Red Cedar.

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Fruticose lichen on a downed oak branch.

 

Lichens can be found in several habitats across Little St. Simons Island, and they take a variety of forms and colors. Lichens have the ability to survive long dry periods, but after a good soaking rain, they will catch your eye with their bright colors and interesting textures.

Lichens are actually not a plant, but a composite of fungi and a photobiont that behave together as a single organism. The fungus usually provides the structure and facilitates the uptake of water and minerals, while the photobiont generates sugars through photosynthesis. The photobiont is usually a green algae, but can also be a cyanobacteria.  In most cases, the fungus and its photobiont would not exist outside of the lichen association.

Lichens have the ability to grow on soil-less surfaces, and therefore are one of the first colonizers in many plant communities. They are very slow-growing, but can derive most of their water and nutrients from the air and rainfall. On Little St. Simons Island, you can find lichens growing on the smooth bark of Southern Magnolias or Southern Red Cedars. You will also find it colonizing open sandy areas.

Lichens can be divided into three groups based on their morphology. Crustose lichens grow flat against hard surfaces (like a crust), and are the simplest form of lichen. As they grow, they radiate out from the center, so the newest growth is on the perimeter. Foliose lichens grow in a more “leafy” structure, but stay close to the surface they inhabit. Fruticose lichens are more shrub-like, growing on a stalk or exhibiting a highly branching, more complicated structure. On Little St. Simons, you can find lichens that belong to all three of these groups.

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Living Shoreline promotes fish habitat and erosion control

Barrier islands are very dynamic landscapes. As the tides, currents, and winds sweep around the island, it continuously changes the landscape. Where you first arrive to the dock at Little St. Simons Island, there has been a wooden bulkhead adjacent to the dock creating a vertical barrier between the creek system and the upland.

Imagine a section of healthy marsh joining the higher ground and the creek. That’s what we invision as we replace this bulkhead with a Living Shoreline.

Bulkheads will weaken and eventually fail over time, and we have been planning on replacing the current bulkhead (constructed in 1995) for several years. However, rather than building another bulkhead that inevitably will have to be replaced again sometime in the future, we are putting in a “Living Shoreline.”

This Living Shoreline will be a more natural slope from the upland into the marsh habitat, and as the name suggests, create excellent habitat for the many organisms that utilize the different zones between the low tide mark and the high tide mark. We will be planting native plants that thrive in the marsh zones whose root systems will help stabilize the sediments, and using recycled oyster shells as structure to recruit new living oysters to the site, which will create habitat for myriad of marine organisms including several species of fish. To learn more about the benefits and implementation of a Living Shoreline, visit NOAA’s resource pages or learn about a similar project on Sapelo Island.

Tom Bliss with UGA’s MAREX and Jan Mackinnon with DNR’s Coastal Resources Division remove their nets after a fish sampling session.

Along with stabilizing the shoreline in a more natural and efficient way, one of the goals of this project is to enhance fish habitat. In order to get some baseline data on what is already hanging out around our dock, with the help of the University of Georgia’s Marine Extension (MAREX) team, we have been sampling the fish populations around the dock for the past year.

Next comes the construction! Scheduled to start in the middle of February, we will begin removing the old bulkhead, and creating the living shoreline. With the guidance of cicil engineer Tom Havens and landscape architect Thomas Angell who specializes in ecologically-sensitive environmental design, we will transform our current bulkhead garden into a seamless junction with the marsh.

In the meantime, as you park your car at the Hampton Marina, you might notice a mountain of oyster shells. As these are put into mesh bags (8,000 mesh bags to be exact!), they will be the foundation for which oyster spat (free-swimming larval oysters) will attach. Overtime, they will grow into a living oyster reef, one of those living oyster reefs that are vital to the functioning of the marsh ecosystem.

Of course, Little St. Simons Island cannot take on such a big project on our own. Our primary partners include: UGA Marine Extension, The Nature ConservancySapelo Island National Estuarine Research Reserve, Georgia Department of Natural Resources, Coastal Resources Divsion, NOAAWe are also working with volunteers from these organizations to help implement the project: Coastal WildScapes, Americorps.

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Naturalist Fact: Prickly pear cactus (Opuntia hemifusa)

Prickly pear fruits are ripening in the fall. Almost ready for sorbet!

The prickly pear cactus (also called devil’s tongue and Indian fig) is a native species of cactus found throughout the United States, east of the Rocky Mountains. It prefers the well-drained gravel and sandy soils found on the island. They thrive in the open sunlight of early plant succession communities and disturbed areas. These iconic desert plants line Beach Road, Marsh Road, and can also be found on the south end of Little St. Simons Island.

The prickly pear can grow to be about three feet tall, with succulent, segmented stems forming wide “pads.” Cacti’s leaves are modified into spines, and on the prickly pear these can be two inches long and protrude from the pads and fruits. Also covering these surfaces are “glochids,” or tiny hair-like barbed bristles that can also irritate your skin.

Showy yellow flowers of late spring give way to a cylindrical fruit that ripens to a purple color in the fall. Both the pads and the fruits of the prickly pear are edible. The melony-tasting fruit can be incorporated into jams, jellies, and syrups (and are a good source of Vitamin C!) Our chefs also use prickly pear fruit in a refreshing dessert sorbet.

 

 

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Sea Turtle Update: Coming to a close

Loggerhead sea turtle hatchling crawls to the ocean. (Photo courtesy of Natalie Folsom.)

Sea turtle season is wrapping up. Our last nest was laid on August 3rd, and all but 20 nests have hatched and been excavated. As the nests began to hatch, we discovered a few “wild” nests, ones that weren’t detected or marked right after they were laid, the only evidence being several tiny turtle tracks spread across the sand.  This brings our total to 116 nests–a record for Little St. Simons Island!

As the beach changed throughout the summer due to winds, currents, tides, and other factors, we accumulated a thick line of wrack (dead Spartina grass) at the base of the dunes. Most of the nests laid in the latter part of the season ended up in this wrack line and therefore had to be relocated, resulting in a high relocation percentage of 60% (70 of 115 nests). However, we are also experiencing a high hatching success rate. The average hatch success rate so far is 73%, and the majority of nests have had 60% success or higher. One of our nests that was relocated this season had 100% hatch success, which is almost unheard of for a relocated nest or ones left undisturbed!

Sea turtle technician, Natalie Folsom, carries hatchlings down to the ocean. (Photo: Britt Brown.)

Five days after we see the first signs of emergence, we will excavate the nest and take an inventory of hatched eggshells, unhatched eggs, dead hatchlings, and live hatchlings. This data is used to determine the hatching success rate for our beach. These excavations also provide a great opportunity to see live hatchlings that may have been unable to make it out of the nest on their own.

We have also had several sea turtles stranded on our beach this year. Two of which were large Loggerheads with splits in their carapace, possibly results of boat collisions. A smaller Loggerhead was found alive and transported to the nearby Georgia Sea Turtle Center on Jekyll Island for rehabilitation.
This sea turtle nesting season has been a busy one for the entire Georgia coast, with a total of 2,226 nests. For more nesting data for the Georgia coast, check out SeaTurtle.org.
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Naturalist Fact: Redbay Ambrosia Beetle

Redbay ambrosia beetle (Xyleborus glabratus)

The redbay ambrosia beetle is an invasive pest first detected in 2002 near Savannah’s Port Wentworth. Originating in Asia, this tiny beetle (2 mm) is thought to have been introduced via infested wooden packing materials at the port. Like several other invasive species, this ambrosia beetle has spread quickly and its effects can now be seen on redbay trees throughout the Georgia Coast and into Florida and South Carolina.

Fungus introduced to redbay trees by the invasive ambrosia beetle causes laurel wilt in the tree.

Unlike native ambrosia beetles, this beetle attacks healthy redbay trees by boring into the wood just under the bark, creating galleries in the sapwood where it will lay its eggs. However, it is not the boring, or even the beetles themselves that will kill the tree. The female carries spores of a fungus (Raffaelea lauricola) in a pouch in her mouth which she inoculates into the sapwood as she bores. The developing and adult beetles feed on the fungus while the fungus grows within the tree. As the fungus grows, it blocks water and nutrient movement within the tree, causing laurel wilt and eventually, the death of the redbay tree.

As you explore the maritime forest here on Little St. Simons Island, you will see sapling redbay trees, with the majority of their leaves brown with wilt. Currently, scientists have not found a method of fighting back against the redbay ambrosia beetle. As the beetle and fungus spread, the redbay could be affected across its entire range. An important host plant to three species of swallowtail butterflies, a decline in the redbay could also mean hardships for palamedes, Schaus, and spicebush swallowtails in the coming years.

For more on the palamedes swallowtail, read our previous Naturalist Fact of the Week.

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Naturalist Fact: Flounder


There are two species of flounder that are commonly found in the tidal creeks and off the shore of Little St. Simons Island, the summer flounder and southern flounder. Both are members of the left-eyed flounder family Paralichthyidae. Summer flounder can be distinguished from the southern flounder by the presence of 5 to 14 eye-like spots called ocelli. Like most members of the left-eye flounders, they can change the color and pattern of their dark side to match the surrounding bottom, and are also capable of rapidly burrowing into muddy or sandy bottoms. Flounder lay buried with only their head exposed to ambush prey which includes many species of fish, squid, shrimp, and crabs. A small body cavity and the absence of an air bladder aid the fish in maintaining its position on the bottom. While primarily considered a bottom fish, they are rapid swimmers over short distances and can become very aggressive, feeding actively at middepths, even chasing prey to the surface. Flounder have a fascinating life history as well. After hatching, the larval fish swim in an upright position and the eyes are located on opposite sides of the head. As the young fish grows, the right eye begins to “migrate” to the left side of the head. When body length of about one-half inch has been attained, the eye migration is complete and the fish assumes its left-side-up position for life. Flounder migrate inshore and offshore seasonally in response to changes in water temperature. During winter and early spring, they are found offshore along the outer edge of the continental shelf where spawning occurs, but in late spring and early summer, they move inshore and concentrate in shallow coastal waters and estuaries. Flounder are considered to be a very important species along the Atlantic coast as it is important to both the commercial fishing industry and very popular for recreational fishing.

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Naturalist Fact of the Week: Common Nighthawk

Nighthawks can be spotted on Little St. Simons Island in the late spring and summer months. Traveling from their wintering grounds in South America, Nighthawks nest across most of North America. They nest on open ground (including the dunes at our beaches), laying two speckled, dark gray eggs. The female will incubate the eggs for 2-3 weeks, leaving the nest to feed in the evening. The adults have cryptic brown coloration, making them almost impossible to spot while sitting on a nest or roosting on the ground.

Nighthawks are crepuscular, feeding and dawn and dusk. Their tiny bills and large mouths help them feed on insects, catching them as they fly. Canadian breeding populations and populations in the Northeast United States have been listed as threatened. Indiscriminate insecticides reducing food sources are a contributing factor to declining Nighthawk populations. Nesting on the ground also makes the eggs vulnerable to raccoons, opossums, ghost crabs, and other predators.

Contrary to what their name suggests, the Nighthawk is not a hawk. They are in the same family as Whip-poor-wills and Chuck-wills-widows. Chuck-wills-widows and Nighthawks can be spotted after dark by their red eye-shine as they roost on the ground.

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