The classic model of ecological succession begins with new land. This could be new land formed by a sand bar, or a new landscape formed after a volcanic eruption, but new land none the less. Then the pioneer community begins. Based on the model, the plants need to be first, herbivores cannot survive unless there are plants already present. When we teach students about maintaining aquaria, we actually begin with the bacteria community needed to breakdown the organic waste from the plants and animals when they arrive. So, some would say “begin there”. As the pioneer plant communities form, the pioneer herbivores arrive. This would be followed by more advanced communities of plants and then more advanced communities of animals, until you reach the climax community.
Beach
The open beach is how most barrier island ecosystems begin awaiting the arrival of the pioneer community.
Phot: Rick O’Connor
But science understands that it is more complicated than that. Each new member of the community would make chemical and physical changes to the environment that could allow new species to thrive while other existing ones die off. Then those would make changes as well and the process is ALWAYS changing. That there is never a true climax community, change is happening all of the time. Then there was the case of Mt. St. Helens.
St. Helens erupted in 1980 destroying 229 square miles of habitat. This new landscape gave ecologists an opportunity to witness ecological succession firsthand. Like everyone, they expected the pioneer plant community to arrive first, and so on. But in some areas, it was the carnivores that arrived first, completely against the classic model. These carnivores apparently survived the blast and began to wonder the new landscape. How did they survive? They survived by feeding on each other. But eventually the pioneer plants did arrive, all creatures “got in line” and the world was good once again. The interesting thing was it did not happen the way they thought it would. It also shows the resiliency of life.
Mt. St. Helens destroyed almost 300 square miles and produced new habitat.
Photo: University of Washington.
So, how did this process unfold on our barrier islands? I do not know. You would guess that it unfolded the way the model suggests – pioneer plants first, pioneer animals, more complex plants, more complex animals, barrier island ecosystem. But as we have seen, there are several ways it could have started.
What we do know is that the animals who made it to the islands had to do so by either swimming, flying, or walking. For those who reached our islands on foot – beach mice, ants, etc. this must have happened at a time when the island was still connected to the mainland.
The Choctawhatchee Beach Mouse is one of four Florida Panhandle Species classified as endangered or threatened. Beach mice provide important ecological roles promoting the health of our coastal dunes and beaches. Photo provided by Jeff Tabbert
For the swimmers, short swims like Indian Pass could be achieved by several species. Deer and other small mammals may have been able to do this. I have seen bears swim and assume coyotes could make short swims. As the island continued to move with the tide and currents, the distance to the island would have increased. The pass across the mouth of our estuaries, or across the intracoastal waterway, is now daunting for many of these swimmers – but not all. I have seen eastern diamondback rattlesnakes swim across the ICW and have heard bears can still make this trip. For the flyers, these distances do not seem to be an issue. They easily, and often, do so.
Eastern diamondback rattlesnake swimming in intracoastal waterway near Ft. McRee in Pensacola.
Photo: Sue Saffron
If you imagine the early days of an island being low elevated sand, the new wildlife arrivals would face a daunting landscape. Burrowers, such as ghost crabs, could easily make a living here. Their burrows protect them from the elements and being scavengers, they would feed on anything the Gulf washed ashore – something they still do. Sea turtles and shorebirds could easily use the sand bars for nesting, and probably preferred it due to the few predators around. But eventually, the pioneer plants would become more established, allowing selected herbivores (who could survive in low elevation sand) to move in. Next the dunes would form, providing new habitat (read part 2 of this series). Additional herbivores, if they could reach the island, could now become established and at some point, the carnivores would enter the picture.
The line of seaweed and debris along the surf zone is called wrack. Photo: Rick O’Connor
There would initially be a finite amount of space for inhabitation and competition for that space and its resources would be high. Some would be more adapted to the environment than others, or physically stronger, or have a higher reproductive rate, to give them an edge over the others and the island wildlife community would begin. This community would include such things as insects, worms, amphibians, reptiles, birds and mammals. The marsh habitat would include aquatic species such as snails, clams, crabs, shrimp, and fish. All would have had to be able to reach the island, find a suitable habitat for their needs, find suitable food, and out compete others who had made the trip across as well. I was asked once as a college student – “who is a rhinoceros’s greatest competition?” It was an oral exam, and I was very nervous. My mind began reeling in all directions trying to think of what a rhino would have to compete for and WHO would be their greatest competitor. And then, with a little discussion from my professors, it dawned on me. Their greatest competitor would be another rhino. The other rhino would be seeking the same resources, habitat, and mates as the original one. Your first problem is with your own kind. And so, it would be for barrier island wildlife.
The bizarre looking armadillo enjoys a walk on the beach.
Photo: Rick O’Connor
With the arrival of humans, with their bridges and boats, additional creatures would be able to reach the islands and play a role in the competition, but that is another story, and we will discuss this more down the road. In Part 4 we will look at the species that have inhabited the beaches of our barrier islands.
Coastal plain honeycombhead blooms through the summer on local beaches. Photo credit, Bob Pitts, National Park Service
Over my years of leading people on interpretive trail hikes, I have learned it is particularly important to know the names of whatever happens to be in bloom. These flowers are eye-catching, and inevitably someone will ask what they are. In fact, one of my favorite wildflower identification books is categorized not by taxonomy, but by bloom color—with a rainbow of tabs down the edge of the book for easy identification.
Wildflower identification can be tough, but color-coded guidebooks are really helpful! Photo credit: Carrie Stevenson, UF IFAS Extension
In our coastal dunes right now, several plants are showing off vibrant yellow blooms. Seaside goldenrod, coreopsis, and other asters are common. Rarer, and the subject of today’s post, is the Coastal Plain Honeycombhead (Balduina angustifolia). It has bright yellow flowers, but often gets more notice due to its unusual appearance when not in bloom. The basal leaves are bright green and similar in shape and arrangement to a pine cone or bottlebrush (albeit a tiny one), sticking straight up in the sand. The plants are typically found on the more protected back side of primary dunes or further into secondary dunes, a little more inland from the Gulf.
When not in bloom, the plant resembles a green pinecone planted in the sand. Photo credit: Carrie Stevenson, UF IFAS Extension
The plant plays a special role in beach ecology, as a host plant for Gulf fritillary butterflies and the Gulf Coast solitary bee (Hesperapis oraria). The bee is a ground-dwelling pollinator insect that forages only in the barrier islands of Mississippi, Alabama, and Florida. The species is currently the subject of a University of Florida study (they’re out at Ft. Pickens right now), as the endemic bee’s sole source of nectar and pollen is the honeycombhead flower. As of publication date, no bee nests have been discovered. Researchers are interested in learning more about the insect’s life cycle and nesting behaviors to better understand and protect its use of local habitats. Based on closely related species, it is believed the Gulf Coast solitary bee builds a multi-chambered nest under the soft sands of the dunes.
Adult female Hesperapis oraria foraging on coastal plain honeycombhead (Balduina angustifolia). Photograph by John Bente, Florida Department of Environmental Protection, Florida Park Service.
While the honeycombhead plant is found in peninsular Florida and coastal Georgia, the bee has been identified only in a 100 km² area between Horn Island, MS, and St. Andrews Bay, FL. Luckily for the bee, large swaths of this land are preserved as part of Gulf Islands National Seashore and several state parks. Nonetheless, these coastal dune habitats are threatened by hurricanes, sea level rise, and development (outside the park boundaries). Due to its rarity and limited habitat, a petition has been submitted to the Fish and Wildlife Service for protection under the Endangered Species Act. 0
You are probably not going to see them… but they are there.
Mammals are fur covered warm blooded creatures. Beaches are hot, dry, sandy places. Just as in the deserts, it would make sense for island mammals to be nocturnal. We know of their existence by their tracks and their scat. Rabbit, raccoon, and armadillo tracks are quite common. Deer, coyote, and beach mice less so. All that said, some are seen at dawn and dusk and it is not unheard of to see them in the middle of the day – especially during the cooler months.
One question that may come up is – “how did they get to an isolated island?” Some scientists have a lot of fun trying to solve that mystery. Some island mammals, like otters, are very good swimmers and would have no problem. Many barrier islands begin as sand spits connected to the mainland – the mammals ventured out into new territory – set up camp – and either over time, or over night in a hurricane – the spit breaks off and the mammals are there. And let’s not forget we built bridges – they know how to use them. Coyotes have been seen walking across the Bob Sikes Bridge from Gulf Breeze.
Another question that comes up – “where are they in the middle of the day?” Most dig, or find, burrows and dens. Just a few inches below the surface it is very cool. Some will find thick hammocks in the maritime forest and “hunker down” for the day.
The sneaky raccoon is an intelligent creature and has learned to live with humans. Photo: Molly O’Connor
Raccoons
The raccoon (Procyon lotor) is one of the more intelligent and fearless of the beach mammals. Their opportunistic behavior frequently brings them into contact with humans. They will scurry across your lawn at night looking for insects, cat food, garbage, whatever they can find to eat – and outdoor lights do not seem to bother them. There are even videos of them reaching into “dog doors” searching. On the island, their tracks are often found in the marsh areas – where they grab shellfish and are one of the few animals that wash their food before eating it. They usually like to settle into hollow trees during the day. But on the island, it is more likely burrows in the sand.
Their tracks might show the presence of a claw (always hard in soft sand – better chance in wet). The front foot is smaller than the back and they walk with an alternating pattern – usually the front and back foot are close to each other – unless they are running. The front foot is about 2.5”x2.5” – a little round, and the index from the pad to the tip is thinner. The hind foot is about 2.5” wide but closer to 4” long.
The bizarre looking armadillo enjoys a walk on the beach. Photo: Rick O’Connor
Armadillo
Here is an interesting creature. It doesn’t even look like a mammal – not sure what it looks like. But mammals they are. If you find one that has been hit by a car you can see, amongst the armored plating, hairs spaced across the body – they are mammals. It is one that is sometimes seen roaming in the middle of the day. They plunge through the leaf litter and bushes of the maritime forest, making a lot of noise, while searching for insects and grubs and crushing them with their peg-like teeth. They are not from around here – rather from central America – and worked their way into the American southwest and southeast. They probably reached the island via the bridges. They are prolific produces – usually having quadruplets of the same sex. You once found them occasionally in the national seashore – but since Hurricane Ivan, you can find them almost anywhere. One bothersome fact of this animal – they are known to carry leprosy – which can be contacted by eating the animal, or handling it.
Their tracks are one of the most common on the beach. The front foot is about 1.8” long and 1.4” wide. You will see only four toes and claw marks may be seen. The two middle toes are longer. The hind foot has a similar pattern, but you will see five toes and they are about 2.2” long. Most tracks include the tail drag between the foot marks. These are quite common all over the island.
The scat is round-ish and not very long – about 2”.
A coyote moving on Pensacola Beach near dawn. Photo provided by Shelley Johnson.
Coyote
This is an animal that makes people nervous. They are one of the larger mammals on the beach, and they are carnivores. Attacks on pets and children are a concern for many. However, this is rarely the case. Studies show that they are actually very nervous around people and tend to stay at a distance. However, if fed cat food or available garbage, they will lose that fear and problems can occur. Like most island mammals, they are nocturnal, and diet studies have found the bulk of their meals are rodents – which is doing us a favor. But, like raccoons, they are intelligent and opportunistic. If they find an easy meal, like shorebird and turtle eggs – or the chicks and hatchlings – they will take them. It was once thought they were creatures of the American west and migrated into the eastern United States. Some scientists have found coyote remains in the eastern US that predate the ice age – so maybe they are just returning home. There are also reports of humans bringing them here for “fox hunts” – not realizing these were not fox. Either way, they are in all 67 counties of Florida, and on Pensacola Beach. They look similar to dogs – but will be thinner and their tails hang down between their legs when they run. One way to know if they are around is to listen when a siren is going – they tend to howl at these.
Their tracks are very similar to dogs and more people are bringing dogs onto the beach and into natural areas – hard to tell them apart. The pad at the rear of both the front and back paws of the coyote has three lobes, dogs have two on the front foot. In general, dog tracks are more round, coyotes typically are long and not as wide. Characteristic of dog family – the claw marks can be seen. Keep in mind that tracks are distorted in soft sand – best to look in wet sand.
The scat is also characteristic of wild canines – long and thin (like a hot dog) and tapered at each end (like a tamale). Coyote scat is usually 3-8” long and may have the characteristic claw scratching marks some dogs do.
The Choctawhatchee Beach Mouse is one of four Florida Panhandle Species classified as endangered or threatened. Beach mice provide important ecological roles promoting the health of our coastal dunes and beaches. Photo provided by Jeff Tabbert
BeachMouse
Beach mice are like the Loch Ness monster – everyone talks about them, but no one has seen one. Many locals have lived on this beach all of their lives and have never seen one – but they are there – and they are protected. The deal with protection is that these are isolated populations on each island. With no chance to mix genes, they have become “unique” and found no where else. There are four species in the state listed as endangered – including the nearby Perdido Key Beach Mouse and the Choctawhatchee Beach Mouse. It is believed the subspecies found on Pensacola Beach is the Santa Rosa Beach Mouse and is not listed as endangered – but is a species of concern (see list in link below). These little guys dig multiple burrows throughout the dune field but prefer those that are more open and have plenty of sea oats. They emerge at night feeding on a variety of seeds, fruits, and even insects – but sea oats are their favorite. It has been suggested they play an important role of dispersing these seeds. The introduction of new predators, and human development, have put these guys at high risk of extinction.
As you can imagine, the tracks are tiny. They are round in shape and show claw marks.
For locals along the coast ghost crabs are as common as mockingbirds and mourning doves. Before Ivan, when the dunes were larger and closer to the road, viewing the white crabs scouring across the road at night in your headlights forced all into defensive driving maneuvers. And for those who have ever tried to catch one, all would agree it is one of the fastest animals on the beach.
The common ghost crab. Photo: Virginia Institute of Marine Sciences
Ghost crabs (Ocypode quadrata) are members of the fiddler crab family. Like their fiddler crab cousins, they are more terrestrial than aquatic and dig burrows to protect themselves from predators and the intense heat of the midday sun. Though ghost crabs can be found in a variety of locations on the island, they are most frequently found between the mean high tide line and the upper portions of the primary dune line; typically on the Gulf side. Their “J” shaped burrows reach the water level below the sand and can run as deep as four feet. Larger individuals can dig deeper burrows and are often found further away from the water’s edge. These are crabs and thus still possess gills. Gills must be in contact with water in order to obtain needed oxygen. To do this ghost crabs have a gill chamber that will hold water for periods of time. The crabs can obtain water either at the bottom of their burrow or by running to the edge of the Gulf. And running is a good term for what they do. Once they have left the burrow they will lift five of their 10 legs above their head running on the remaining five. Running sideways they will have three in contact with ground in the direction they are going and two on the opposite side; if you look closely you can actually the remaining legs raised high in the air. When they tire, they will stop, make a 180° turn, and begin running again; resting their legs. They have reached speeds of 1.6 meters/second, which is 3.5 mph!
Ghost crabs are most active at night, though they are found at dawn and dusk and occasionally at midday. They feed on invertebrates at the surface zone such as mole crabs (sand fleas) and coquinas (bean clams). Dead fish and other animals found along the shoreline are also part of their diet, often dragging them back to their burrow. Unfortunately they are one of the predators of sea turtle hatchlings heading to the Gulf at night. Ghost crabs breed in late spring and early fall. The females will carry her developed eggs to the surf zone to release them. The developing young will return the following spring to mate and release their own eggs. Females may produce eggs in their second year but rarely live to do the same the third year. They are quite social with other crabs communicating, like their fiddler crab cousins, with body postures and claw movements. They are most active from March to December, plugging the entrance of their burrows and going dormant during the colder months of the year.
There has been concern about the impact of the oil spill on their numbers and the numbers of their prey, mole crabs and coquina. Our beaches did have small and large patches of oil that seeped down into the sand and then there were the methods used to remove the oil from the beach. At this point we do not know how hard their populations were impacted but scientists have collected data before and after the spill and are analyzing this now. However low their population dropped I am sure these resilient creatures will rebound and we will once again dodge them during our evening drives.
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