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Invasive Species – Lesson 6

This week, we are turning our attention to an invasive species we call EDRR (Early Detection, Rapid Response).  In the invasive species world, there is something called the invasive species curve (see diagram).  The yellow to dark red curve represents the population of the invasive species.  At first there are very few, then the population climbs, then population levels off and remains slightly constant (albeit there are a lot of them).

The Invasive Curve
Image: University of Florida

At the beginning, and through the “yellow” portion of the curve is your best chance to eradicate the species from your area.  Once it reaches the red – you are in what we call “management mode” – you are not going to get rid of them.  The other species we have discussed in lessons 1-5 are in “management mode”.  Another example would be the lionfish.  But there are potential invasive species that are not here yet or are in very low numbers.  THESE we term EDRR Species and these are the ones we can possibly eradicate if we know about them and react quickly.

The invasive Cuban Treefrog.
Photo: University of Florida Wildlife.

Our first EDRR species will be the Cuban Treefrog.  This frog is considered invasive.

#1 – it is from Cuba, the Bahamas, and other Antilles Islands.  So, it is nonnative.

#2 – it was brought to Florida in the 1920s on a boat, probably accidentally.  So, we brought it here.

#3 – it is a large consumer of native frogs and reptiles, it has been known to short circuit HVAC systems while hiding in them, they like human habitats and make a loud annoying call (some folks consider this a problem).  So, they are causing both an environmental and an economic problem.

 

They have become established (in the red portion of the curve) in much of south Florida as far north as Gainesville.  There are not yet established in the panhandle.  There have been five reports in the Tallahassee area, four from Panama City, four from Pensacola, and one from Eglin AFB.  Of the ones in Pensacola they have all been single individuals that were removed.

 

HOW DID THEY GET HERE?

We think the most common method of spreading is on plants from the nurseries in south Florida.  Most of the plants you purchase at the big stores are grown in large nurseries down near Homestead FL.  These are loaded onto trucks and delivered here – many times carrying lizards, frogs, spiders, and other south Florida creatures.  You purchase the plant and bring the creature home.  Wah-La… introduction.

In each local case, this is what happened.  A new plant was purchased for landscaping and then they found this really large treefrog on their door or window.  But they can hitch hike on other vehicles (campers) as well.

 

A similar story happened at the Audubon Zoo in New Orleans.  They had purchased nine palm trees from a south Florida nursery for their elephant exhibit.  A few days later the staff noticed all of these strange looking frogs.  They called the state wildlife group who immediately feared what they had.  Arriving, the first checked an electric panel in one of the boy’s restrooms (a favorite haunt of the CTF during the daylight hours) and found 30 in there.  They began to find them everywhere including the cracks of the wooden posts holding up a fence along the river walk – they were invested.

 

I recently was camping on the north side of Lake Pontchartrain and found one in their bathroom – I believe that the New Orleans may now be in the red part of the curve for these unwanted frogs.

 

HOW DO YOU KNOW A CUBAN TREEFROG WHEN YOU SEE ONE?

This is a good question, because you do not want to remove a native one.

They like to be around human homes and will come out at night near your porch lights to hunt.  They are big, warty, treefrogs that can be green, beige, even brown and usually lightly spotted.

A large Cuban Treefrog captured in Collier County FL

#1 – They are much larger than our native treefrogs.  Our natives will reach 1-2 inches, the Cuban Treefrog will reach 5-6 inches.  I found one last year in Ft. Myers that was almost the size of my hand (photo).

#2 – They have warty-bumpy skin – however, some of our native species do as well.  We have four species that have little bumps and are called “granular”.  There is one with larger bumps, or warts, like the CTF and that is the cricket frog.  The cricket frog differs in that it has a triangle pattern between the eyes, the skin between the eyes is loose (not fused to the head), and it does not reach such large size.

#3 – CTFs will begin life small – so how to do you tell then?  With a small CTF you can look at its belly side and the skeleton appear blue through the skin.

 

HANDLE WITH CARE.  CTFs produce a mildly toxic slime that can irritate the skin and eyes.  We recommend handling with gloves – or – wash your hands after handling and do not put near your face until you do. 

 

WHAT DO I DO IF I FIND ONE?

Call me 😊

Then let’s report it on EDDMapS.

We will go from there.

 

For our activity today, we are going to set up a “treefrog trap” and see what we find.  Chances are VERY low you will find one in your yard – but you may…

 

ACTIVITY

          See if you can log onto EDDMapS and see the distribution of Cuban Treefrogs in Florida.  Good practice.     

          Building a Treefrog Trap

1)      You will need a 3-foot section of PVC pipe about 1.25” in diameter

2)      Cut one end at an angle so it is easier to hammer into ground

3)      Find a location near your house where the outdoor lights can be found, and a bush or tree is nearby.  Place the PVC tube(s) in the ground near the house.

You are set.  Now just check it each morning and see what you have.

If there are small green treefrogs in there (will have smooth skin and a white stripe along the side) – cool, let them hangout if you like, they like it in there.

If you find the large warty Cuban Treefrog, place a Ziplock bag over the top of the pipe.  Remove the pipe from the ground.  Using a broom handle (or something similar) go from the bottom and force the CTF into the Ziplock bag and call me 😊.  (roc1@ufl.edu )

Treefrog Trap.

Volunteer showing how to get the CTF into a Ziplock bag.

We will discuss more EDRR species in the coming weeks.  You probably do not have any… but you might.

 

HAVE FUN AND STAY SAFE.