Follow Solberg on a Survey

Two weeks ago I described some of the work being conducted by Cliff Maehr and Jenna May at the Florida Panther NWR. This week I am excited to take you with me on my Anuran Survey. With our wildlife conservation heroes Batman and Swallowtail…I felt obligated to give myself a catchy conservation-orientated nickname. And thus, Anurman was born! His attention for detail and affiliation for frogs has given Anurman an edge with anurans. Anura is the Order that encompasses all families of frogs and toads. So if you’re not sure whether it’s a frog or a toad, you can call it an Anuran and never be wrong!

Project Background

Here at the Florida Panther National Wildlife Refuge I’m seeing how many different species of Anurans I can find across different habitats on the refuge. Because frogs and toads have permeable skin and a biphasic life cycle, they are very sensitive to disturbances. Alterations to habitat, pollution, and too much exposure to UV rays are more likely to affect Anurans before they begin affecting other animals like mammals. And because of this sensitivity, Anurans are a great indicator species of ecosystem health. If an area is being affected by a disturbance, Anurans are one of the first to go!

Using Anurans as an indicator species allows one to assess habitat quality and managment applications. In addition, you can prioritize restoration work. This is important when you have little funding and a large area of habitat to manage. This is something I hope to contribute to the Florida Panther National Wildlife Refuge.

So as a very general rule,
Anurans within an Ecosystem = Healthy Ecosystem

However, there are some exceptions to this. Bull frogs and cane toads can be found in high densities in disturbed areas! Sometimes our actions make conditions good for one species. Think about crows, mice, and other generalist species. So by looking at the number of species present or species richness, I am able to get a more accurate representation of ecosystem health. After all, you can’t put all your eggs in one frog…or basket, whichever you prefer!

My neighbor Fred
Southern Toad, Bufo terrestris

So what is the best way to survey Anurans? Some species like this Southern toad vist my house on a daily basis. Fred is easily captured, identified, and extremely predictable. But what about other species? There are a lot of variables to consider:

• Time
• Funding
• Manpower
• Transportation
• Tools
• Accessibility
• Season
• Time of Day
• Weather
• Region
• Habitat
• Site
• Terrestrial Species
• Aquatic Species
• Are Species Active?
• Do Species Call?
• Are Species Easily Captured?
• Can Species be Identified Easily?

Just to name a few…

Although I did some undergraduate work with amphibians, I didn’t realize the extent of surveying Anuran species until I designed my own study! So I did the sensible thing and started Googling.

Once I had the basics, I began conducting some more in-depth research. I found that Florida has 33 species of Anurans! Of these only 17 species occur in the South Florida Region (14 native species and 3 introduced species). Out of these 17 species in South Florida, 5 species are tree frogs (Family Hylidae). That encompasses nearly a third of all the species in my area! So I decided to set my sights on them.

Green Tree Frog, Hyla cinerea

Tree frogs are easily identified by their large toe discs, long limbs, and slender waists. Arboreal creatures, tree frogs spend much of their time inhabiting trees. They often seek refuge in moist tree nooks or within the boots and fronds of palms. Thats not to say they can't be found on the ground! You can often find tree frogs hiding around your garden hose in warmer months. A popular method for catching such frogs is the use of pvc pipe. Small diameter pvc pipes provide a safe refuge that can easily retain moisture and provide a humid home for tree frogs. Few animals can climb up pvc pipe, so this method helps avoid indiscriminate capture. After all, you wouldn’t want to find a venomous snake in your pipe!

Methods

Pvc pipes were cut, drilled, and placed at chosen sites on the Florida Panther National Wildlife Refuge. I chose sites based on habitat type, proximity to water, and accessibility.

Three days a week, I wake up early and hop on the ATV to visit my survey sites. Every morning brings new wildlife encounters and lessons. I have the opportunity to see first-hand how these different habitats change over time. And what’s more exciting than checking the unknown? You never know what you’re going to find at the bottom of a pvc pipe. One morning I found a half-frozen Green Anole lizard. He must have fallen in the pipe scampering up a tree. But a few hours in my pocket had the lil fella good as new, before he was released back into the wild.

During every capture event I record the species, size, weight, pipe, site, and date captured. Weather data is also an integral part of my data collection.

Results

Thus far the only species of tree frog I have captured in my pvc pipe refugia is the Cuban tree frog. They are an invasive species of tree frog introduced from Cuba. These frogs not only out-compete native species but will eat native species as well! So despite my inability to assess habitat quality from one species, my results have opened my eyes to perhaps, a larger issue.

A massive Cuban Tree Frog, Osteopilus septentrionalis

When things don’t go according to plan… take what you can from it and learn. Because you never know where it will take you!

Wishing you all the best,
Matt Solberg