Barrier Island Wildlife in the Florida Panhandle; Part 5 The Dunes

Barrier Island Wildlife in the Florida Panhandle; Part 5 The Dunes

The dune fields of the panhandle barrier islands closely mimic those in the deserts of the American southwest.  With rolling hills of sand (less the rock), small, spaced shrubs, and high temperatures, hiking through the dunes reminds me a lot of hiking the deserts and canyonlands out west.  Oh… and you rarely see wildlife in both habitats. 

There are many forms of wildlife that are very hard to find in our area. But we continue to look. Photo: Rick O’Connor

It’s not that wildlife is not present, its just not visible – and this would be true for both habitats.  These systems are more open, easier to spot predator and prey, and the temperatures can be extreme.  Because of this the animals who reside here are more active at other times of the day and we are made aware of their presence by tracks or scat. 

The deserts of the American southwest are ecologically very similar to the dunes of barrier islands. Photo: Rick O’Connor

In winter the temperatures in the dunes can get quite cold.  Being in the eastern United States, and closer to the warm Gulf Stream, the atmosphere is more humid and cold temperatures can feel even colder – the “wet chill” everyone talks about.  Add to this the winds from the north and it can be an unpleasant place to be out and about.  Many plants have gone dormant not producing flowers or seed, and the leaves falling or shriveled and brown, and you have very little for the herbivores to feed on.  When conditions get like this animals have basically two options.  One, hunker down, hibernate, wait for conditions and food sources to improve.  Two, leave – head south where conditions are more favorable.  Either way, you do not see them. 

A hike in winter finds little wildlife moving about.  Birds are common.  Many have flown south from harsher conditions further north and seem to enjoy being out.  Unless it is unseasonably cold and windy, you can find a variety of passerines (songbirds) in the shrubs and bushes of the dunes.  Mockingbirds, cardinals, and mourning doves are often seen.  There are also unique species more common up north.  Christmas time is a popular time for the Audubon Society to conduct their annual bird counts.  Many volunteers often log species rarely seen during other times of the year. 

Mockingbirds are a common passerine bird found on barrier islands. Photo: Rick O’Connor

Mammals and reptiles are not often seen during the daylight hours.  Some reptiles may come out of hiding on days when the sun is bright, and the winds are low.  They will find a windbreak near a dune and bask in this sunlight for a few hours.  But to see them it is one of those “being in the right place and the right time”.  Daytime is short this time of year and they are not out very long. 

Mammals being endothermic can move around.  They are still not frequently seen during the daylight hours because the habitat is too open and hunting not as successful.  There are also a lot of humans on our islands now and many mammals are not fond of this and tend to avoid us.  So, they change their pattern of activity to other times.  Animals who are active during the daytime are called diurnal.  Those more active at night are nocturnal.  And those more active at dawn and dusk are called crepuscular.  During the winter many mammals tend to be more crepuscular because the evenings can get quite cold no matter what the wind is doing.  If they are not hibernating, they will hunt for a few hours at dawn or dusk and then hide during the colder parts of the evenings. 

During my winter hikes I have seen primarily passerine birds, and occasionally an armadillo.  But most sign of wildlife are the tracks of raccoons, coyote, and deer. 

Raccoons are common all over the island.

In the spring things change.  The earth is tilting more towards the sun, the days become longer, and the cold air masses are met by the more tropical warmer ones.  Temperatures and rainfall increases.  These warmer temperatures are more inviting to daytime foraging for prey.  Ephemeral ponds form due to the increase rainfall.  Island amphibians take advantage of this mating and laying their non-cledoic eggs in these ponds while they are still there.  The warmer evenings are filled the calls of male frogs seeking females.  Mammals are still more crepuscular and nocturnal, but it is a time when your chances of spotting one during the daylight hours increases.  Not only is the weather better but the food sources are as well, and some have been hibernating for a couple of months and are quite hungry.  Hunger will push them to be more active during daylight than they would otherwise be.  The same can be said for reptiles.  Snakes moving during daylight is more common this time of year. 

Freshwater ephemeral pond.

This is also the time for mating.  It will be warm for several more months and this is the best time to raise a small offspring.  The temperatures are warmer (conducive to growth), food more abundant (needed for growth), and you avoid the colder temperatures that can kill small animals.  Males of these species are out and about seeking females and defending territories.  Nesting birds of several varieties can be found building such nests.  Turtles and snakes are breeding and seeking good locations to lay their eggs.  With all of this comes more activity and more encounters by human hikers. 

Let’s not forget the insects.  Actually, you can find these creatures at all times of the day in all seasons.  Insects are one of the most resilient groups of animals on the planet, and their high diversity – even on barrier islands – supports this.  In the spring when the rains come and the ephemeral ponds are available, insects begin to breed and fill the skies.  Spring is a very active time in the dunes. 

This tick was a hitchhiker on our trip through the dunes. Photo: Molly O’Connor

Summer brings the heat – particularly late summer.  Like the deserts of the southwest, temperatures can rise above 100°F and it is not the best time to be out and about.  Much of the wildlife becomes more crepuscular or nocturnal.  I have noticed when doing snake surveys, that the snakes may be moving at dawn but by 8:00-9:00am, when you begin to feel the heat of the day, you find no more.  They have moved to the shade or a burrow somewhere.  BUT the lizards begin to move.  Lizards are a popular food for snakes, and it makes sense they would be more active when snakes are not.  However, the sand is hot, and birds are also predators.  So, lizards, like the six lined skink (Aspidoscelis), move VERY fast across the hot sand from one bush to another.  I even notice the passerine birds becoming less common as the heat increases – it is hot out there.  Interestingly human activity seems to increase when the temperatures are at their highest.  We tend to sleep later than most animals this time of year. 

This straight line the sign of a tail drag by a lizard, most likely the six-lined skink.

The fall brings some relief from the heat.  As the earth begins to tilt away from the sun and the days become shorter, the temperatures begin to drop, and it is more comfortable coming out during daylight hours.  Humans are still around so many will still avoid daylight but it also a time to prepare for winter.  Seeking food resources and eating as much as possible is the rule for many.  For some it is also a time for breeding.  Carrying for offspring in a den or burrow over winter is an option for some species.  Because of this they are out seeking mates and may be seen during daylight hours when doing so.  This would include some of the snakes like the eastern diamondback rattle snake (Crotalus) and the cottonmouth (Agkistrodon). 

Coyote seen on Pensacola Beach. Photo: Kristen Marks

Though dunes seem void of wildlife there are actually many species that reside here and even more than transient there from other parts of the island.  Hikes through the dunes can bring magnificent sunrises and sunsets, just as you see in the deserts out west, and – if you are there at the right time and not moving too much – some really neat wildlife encounters can occur.  But further back on the island exist the maritime forest.  Here there are more creatures and more encounters.  This will be the focus of Part 6. 

Photo: Molly O’Connor

Beach Mice of Florida

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

The Choctawhatchee Beach Mouse is one of four Florida Panhandle subspecies classified as endangered or threatened. Beach mice provide important ecological roles promoting the health of our coastal dunes and beaches. Photo provided by Jeff Talbert

Sea Turtles are one of the largest and most beloved animals associated with Florida coastal habitats. However, there is a tiny creature that depends on the coastal dune system that few get a chance to see, the beach mouse. As the name implies, beach mice make their home on beaches and in nearby dunes. These mice are a subspecies of the oldfield mouse. There are eight subspecies, five on the Gulf Coast, two on the Atlantic, and one extinct species.

The Florida Panhandle has four beach mouse subspecies: (in order from East to West) St. Andrew beach mouse, Choctawhatchee beach mouse, Santa Rosa beach mouse, and the Perdido Key beach mouse. Beach mice utilize the primary and secondary dunes for food, water, cover, and raising young. They have many burrows throughout the dunes and forage on seeds, fruits of beach plants, and insects. Beach mice are most active during the night and considered to be nocturnal. Under the cover of darkness, they make several trips in and out of their burrows to find and cache food.  Feeding activities of beach mice disperse seeds and plants, adding to the health of the dune ecosystem.

Worldwide, the biggest threat to ecosystem biodiversity is habitat loss and fragmentation. Since beach mice are dependent on one specific type of habitat, it makes them susceptible to natural and human created disturbances. Due to loss of their primary and secondary dune habitats, all the beach mice except for one are classified threatened or endangered. The Santa Rosa beach mouse is the only subspecies that is not listed as threatened or endangered due to most of their habitat being protected within conservation lands on Santa Rosa Island.

Beach mice populations are continually monitored to track movement, growth, and reproduction. The common method for population counts is through the use of traps and track tubes that record mice tracks. Track indices have been developed to estimate mouse abundance.

Choctawhatchee Beach Mouse photographed during research effort in South Walton County.  Photo by Jeff Talbert

Choctawhatchee Beach Mouse photographed during research effort in South Walton County. Photo by Jeff Talbert

A collaboration of three state agencies just concluded a five day population study of the Choctawhatchee beach mouse in south Walton County. The purpose of this effort was to study the movement in heavily (beach mice) populated areas and the effects of non-native predators on those populations. Predators specifically studied were feral cats, foxes, and coyotes. The study also evaluated the 2011 re-introduction of 50 beach mice, from the Topsail Hill Preserve State Park population into the Grayton Beach State Park population. Reintroduction was done to boost numbers of the mice in that area and expand the gene pool for the subspecies.

The data from the current effort is still being analyzed but positive results are expected due to healthy beach mice being found in areas of focus and some new areas. Public lands such as parks and wildlife refuges are important for the preservation of beach mice as well as other coastal dune species that utilize similar habitats.  It is important that awareness be shared on these and other species to help these efforts to keep our habitats safe and healthy.

For more information on marine science and natural resources information, email or call bsaari@ufl.edu or 850-689-5850.

Beach Vitex… Is It a Growing Problem?

Beach vitex expands it's woody rhizomes aggressively; it can actually grow over sidewalks.

Beach vitex expands its woody rhizomes aggressively; it can actually grow over sidewalks and driveways.

 

It’s actually a pretty plant, this Beach Vitex (Vitex rotundifolia), and it is very good at stabilizing eroding dunes. In the 1990’s, the state of South Carolina planted this shrub to help restore dunes lost during hurricanes. It was selected because of salt tolerance, production of woody rhizomes (runners) that extend over 60 feet to trap sand, and the beautiful purple flowers that attract beneficial insects; it seemed perfect! However, folks along the Atlantic coast had no idea how invasive it would become a few years later. Residents discovered that it chokes out many of the native species such as sea rocket and sea oats producing an area of only this plant.

 

 

It is now causing problems for sea turtles. As you can see in some of these photos, the plant grows over the fore-dune, blocking access for nesting. Beach Vitex grows so aggressively that during the 60 day incubation time many turtle nests are overgrown, entrapping the hatchlings. Some have been found dead, entangled within the rhizome mats. The Beach Vitex “invasion” has become so bad that South Carolina developed a Vitex Task Force to deal with the problem.

 

 

This yard on Pensacola Beach has become over run by vitex.

This yard on Pensacola Beach has become overrun by vitex.

Is this a problem for Florida?

According to the records the Early Detection and Distribution Mapping System EDDmaps.com, Beach Vitex is distributed northward to the Chesapeake Bay area and south to Jacksonville. It is found in coastal Alabama and there is one record of the plant in Escambia County.

With so few records in Florida it is not currently listed as an invasive species in our state and there is no program set up to control it. However the Sea Grant Extension Agent in Escambia County, Rick O’Connor, was alerted in 2013 that vitex was in Gulf Breeze, Florida (Santa Rosa County) and possibly on Santa Rosa Island (Escambia County).

 

 

Please circulate to area residents to provide visual identification of Beach Vitex. Contact your Extension Office for control options and help reduce it’s impact on native species.

 

A “Wanted Poster” was developed by O’Connor to post in the coastal communities of Escambia and Santa Rosa counties to see if the plant was more common than the records indicated. At this time, six properties on Santa Rosa Island have confirmed records of Vitex and two more will be surveyed soon. The wanted poster program was published in the local newspaper which reached the east coast of Florida. Reports from that coast indicate that it has extended south into Volusia County. Okaloosa/Walton Sea Grant Agent Brooke Saari is posting the wanted poster in those counties to see if the plant has reached their coasts.

 

 

 

The owner of this yard mowed the vitex.  However the woody rhizomes are still present.  They will need to either dig this up or use mutliple chemical applications to completely remove.

The owner of this yard mowed the vitex. However the woody rhizomes are still present. They will need to either dig this up or use multiple chemical applications to completely remove.

 

Anyone along the coast of the Florida Panhandle who feels they may have this plant can contact either Rick O’Connor (850-475-5230; roc1@ufl.edu) or Brooke Saari (850-689-5850; bsaari@ufl.edu) and we can confirm identification. The plant is not currently listed as invasive in our state and removal is not required. However, based on the experience in the Carolina’s and other invasive species, if you wish to eradicate this plant doing so early is important. It is much less labor intensive and less costly when there are few plants. If you do choose to remove it please contact your local Extension office first. We can provide methods of successful removal. We would also like to photograph and log the record on EDDmaps.

Editor’s note: Rick provided all the photos in this article.