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Category Archives: Exotic South Florida series

A NatGeo chameleon hunt and more Ventures ahead…

Hey folks,

Its been almost a year since my last post – it has been a turbulent year, but the posts will be picking up again – starting here. I’ve started this semester as a full-time professor at Montreat College – a small Christian liberal arts college in western North Carolina. I’ll be teaching biology and environmental science classes, and of course bringing students out to look for reptiles, amphibians, and all sorts of other creeping things.

 

In the meantime, I’ve got another book in the works and some collaborations with other universities. And, of course, the occasional wildlife filming. Just this past spring I got out with NatGeo and some friends from the Souh Florida Herpetological Society to look for some chameleons. They ended up putting out a well-put together video (of course – it’s NatGeo!) and we had an excellent time that had us out until morning broke in southern Florida. Check it out here, with the accompanying video: http://news.nationalgeographic.com/2017/06/chameleons-ranching-florida-invasives-pets/

 

the best is yet to come,’

JDH

 

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Exotic South Florida: Farming For Chameleons?

 

Hello all, I’ve finished up my Master’s Degree and finally have some free time on my hands that isn’t spent working on theses and whatnot – so a little thought I’ve been musing on for some time… But first, an anecdote:

 

 


I walked through the lonely rows of twisted avocado trees, intently scanning for something off… Something that would betray my saurian quarry, something – there it was! A flash of light green, almost lime in color, a telltale sign that I had not only found my target species the Oustalet’s Chameleon (Furcifer oustaleti), but that I’d turned up a female at that. I got a little closer, waiting for the color to make itself manifest as a curly-tailed shape. But it didn’t: I got close and examined the light patch in the illumination of my headlamp, and sure enough: t’was a caterpillar.

 

Such has been a typical scene from searching for Oustalet’s Chameleons in Dade County from the past year-or-so. Chameleons are becoming ever-harder to find because of constant nightly pressure from collectors of every sort, and their roommates in the agricultural lands they call home – caterpillars, other insects and Anoles of various species – seem to be abundant. Of particular note are the caterpillars, which the grove workers have complained of late have a tendency to eat the leaves on the avocado trees, which in turn affects the overall fitness of the plant, and in turn fruit production. What’s interesting is, when I first started looking for Oustalet’s in years past, these chameleons were plentiful: a dozen or more in a night was little problem oftentimes. During this time one of the only living things found in the grove were the chameleons themselves: seldom if ever was a caterpillar or insect of any kind detected.

So, given the concerns in southern Florida about overuse of pesticides, might we not turn to herpetofaunal biocontrol? These chameleons have the potential to limit prey species, which coincidentally are often agricultural pests species – in fact, a study done by UF found that most of their diet consisted of insects (http://www.conference.ifas.ufl.edu/intecol/presentations/Posters/Vinci_Chameleon_Final.pdf). Obviously, the big question here is whether Oustalets (or Veileds, or any other species for that matter) have the potential to become invasive. This is a question that has received little research (and understandably so: there are bigger exotic fish to fry!) but as of now it does seem that they are largely dependent on agricultural areas as a source population, though they have been found in far lesser densities outside such areas. Let’s hear from some of the Field Ventures readers: what do you think about Oustalet’s Chameleons (or other species) as pest control in Florida?

 

 

 
 

A ‘School’s out’ Field Venture

Well, schools out for the winter: I just finished the last class of my Master’s Degree, and before hunkering down to write my thesis, I figured a little celebration was in order. Soon after such a decision, the question arises of what to do. It’s Florida and there are as many options for field herping fun as there are counties, species and natural areas. Well, it turns out my in-laws had been visiting and had forgotten a jacket at our house, but were a mere 3 hours away in Florida’s Southwest reaches, and that’s about as good of an excuse as I need. Given that the trip I had in my head was due to run me all day and most of the night, I needed a “herping bud” to make sure I didn’t fall asleep behind the wheel or die alone in the coils of a python (kidding about that second one) and my friend Josh Young was able to join me despite the last minute text.

 

Seven AM and we hit the road; flipping our way around Lake Okeechobee. Already it was hot, hotter than I’d expected (86 degrees or so was the high) and I figured flipping would probably be fruitless in terms of our target for the morning, Scarlet Kingsnakes (Lampropeltis elapsoides) – this is a small and fossorial species and although they can be very easily found under artificial human-generated cover (AC), the window to actually flip them is quite small and temperature-dependent. And we missed that window. But, though fruitless it was not pointless: just being out in the field and looking under boards is like opening presents on Christmas morning. We did find a couple of racers; a lump of coal, to keep with the metaphor, for many snake lovers. But I love seeing them out and about – such a prolific and successful species should be admired. But, even still, nothing else under AC, so it was time to mosey.

We drove on a bit and decided to try for an Eastern Indigo Snake (Drymarchon couperi) – Not an impossible snake to find, but they take some effort: seeing the glimpse of a big, thick deep-black snake swagger across the road usually comes at the cost of lots of time and gas (or calories, if you are hiking them on foot.) And yes, I did use the term “swagger” – this species never seems in a rush to get where it’s going, and will slither with palpable confidence through the scrub or across the road; an impressive sight, but probably unfortunate as a 5+ foot snake is easy fodder for passing cars. So we turned down the road we were to cruise, as I said to Josh “This is where we’ll start looking for them.”

Five or ten seconds passed followed soon after by a anatomical chain reaction: an adrenaline rush. Sitting right off to the side in the road in the palmettos was a ~6 foot Indigo. Given this a federally protected species, it isn’t legal to manipulate them for photos, so I had to be content with only a couple of pictures that I was less-than-satisfied with, but ahh well. The best of the bunch:

 

Beautiful!

 

Victorious in this goal, we continued south to the southwestern Florida coast, stopping along the way for some delicious Barbeque. That evening we went to a coastal area and searched for Mangrove Salt Marsh Snakes (Nerodia clarkii compressicauda), a species I’ve been working with on a few projects over the past year. We turned up a few, some of them hybrids: but I’m going to dedicate some posts specifically to them a little later, so that’s all for now. It’s at this point that my friend Jason W joined up with us for some of the excitement. I don’t get to see Jason too often, so it’s always enjoyable to chat about herping adventures and whatnot.

 

Finally, the evening brought us to an area where the landowner was nice enough to let us look around for another species near and dear to my heart: Florida’s exotic Veiled Chameleons (Chamaeleo calyptratus). We didn’t find a ton, but we found a pair of beautiful males:

A little closer, believe it or not the hardest part of photographing chameleons is getting them to actually look at you:

 

Josh and Jason with one of the veileds:

 

And myself with the two of them:

 

A great celebration after lots of hard work. Expect more posts soon.

 

JDH

 

Exotic South Florida Part V: The Veiled Chameleon (Chameleo calyptratus) in Florida

Well, based on the lovely statistics that WordPress sends me, most people find my blog by searching for “Chameleons,” it would seem. Well, there are other species other than the Oustalet’s Chameleons (which I’ve talked about previously) here in Florida. The most well known, and perhaps most dear to my heart, is the Veiled Chameleon. Well known because they are widespread (In at least 5 counties, by my reckoning); and dear to my heart because they are, in fact, the one animal species I have been shot at while looking for.

These chameleons from Yemen have been in the pet trade for a number of years. Though they can often be expensive and/or tedious to keep in captivity, they thrive in southern Florida for a number of reasons. Of course, food is typically abundant in the disturbed habitats where they thrive, and chameleons are slow, yet deadly predators; however the real thing that has a potential to limit their distribution is the cold weather. They can succumb to frigid temperatures just like any other reptile: Veiled Chameleons, however, have a trick up their sleeve. They have the ability to burrow down – up to several feet – under the ground, and will readily use this ability to find refuge from frost and extreme cold. There is yet another use for this magnificent adaptation: they will use the same excavation ability once full grown (which takes less than a year) to make a safe, temperature-buffered chamber in which to lay their dozens of eggs. And I mean ‘dozens’ most literally: one individual I found a few years ago laid about 70 eggs.

By one way or another, it seems the hardiness of these chameleons became well known and they began to be spread by helping hands across the southern peninsula of Florida and eventually some of the populations began to be published (See Krysko et al, 2004). And, once published these sites attracted many more visitors – some not observing the trespassing laws, jumping fences and wreaking havoc with concerned locals.

Interestingly enough, though these lizards are certainly exotic, at times hard to find, and can have voracious appetites; I haven’t seen any evidence as-of-yet to suggest that they are invasive. To be clear: an exotic species is not necessarily an invasive species. In fact, as far as is known the majority of exotic species that end up getting released into a new environment die off rather quickly, and a majority of those that do survive will not be able to find a mate and reproduce. But even if an animal is able to reproduce in the wild, it still may not meet the distinction of being invasive. According to the USDA, an invasive species is one that is “non-native (or alien) to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm or harm to human health.”

Does the Veiled Chameleon meet these criteria? Perhaps it will be found to, but given the evidence at this point in time we cannot but sure, so it would be premature at best and completely false at worst to label them such. These are a species which thrive in disturbed habitats in Florida, habitat which is often comprised of mostly exotic plants to begin with; and even so it is not entirely known what they eat in Florida: many keepers of the species note their affinity for eating brown anoles in captivity, an invasive species itself, and a species for which the south Florida ecosystem would benefit from reduced numbers.

Now, I don’t make this argument as an activist of some sort who is “pro” having chameleons in the wild in Florida, I only wish to make the point that we do not know. It would be a mistake (and a common one) to assume that this lack of knowledge means that the Veiled Chameleon is a completely harmless exotic; and it would be equally foolish to assume that this is an invasive species here. For myself, the lack of knowledge more than anything is an invitation to let curiosity run wild and seek out the truth of the matter: to delve deep into the species, to watch and to study it. And hopefully one day, to know it – that is the essence of why I became a biologist in the first place.

Krysko, K. L., K. M. Enge, and F. W. King. 2004. The veiled chameleon, Chamaeleo calyptratus Duméril and Bibron 1851 (Sauria: Chamaeleonidae): a new exotic species in Florida. Florida Scientist 67:249-253.

 

Exotic South Florida Part IV: The Benefits of Burmese Pythons?

Let’s infer for a moment.

We know:

A.)  There are Burmese Pythons in southern Florida.

B.)   These Burmese Pythons are breeding.

C.)   Burmese Pythons must eat to remain in southern Florida and breed.

D.)  The preferred food of Burmese Pythons, based on stomach contents surveys, is overwhelmingly endothermic/warm blooded in nature.

These are all facts. From these facts we can infer that Burmese Pythons are probably eating a good number of warm blooded animals, that is, Birds and Mammals. Based on this hypothesis I researched and co-wrote a paper (https://fieldventures.files.wordpress.com/2011/07/holbrookchesnespythonsflsc-74-01-17-24-e.pdf), hoping to see if there were, in fact, fewer mammals sighted where the Pythons were established. It turns out, much fewer mammals were observed in the Python’s range when compared to a similar area outside of the Python’s range. Now, my study (and every other study so far,) was not designed to and does not prove that the paucity of mammals in the Everglades is because of Burmese Pythons; but it does allow us to give an educated guess and allow me to make this statement with good conscience: it appears that before the large python die-off in 2010, there were enough pythons in Florida that they were having a significant effect on mammal populations.

Though mammals such as this Florida Panther are for the most part safe from Python predation, most smaller mammals are vulnerable to Pythons.

For more discussion on this aspect, read my paper. But for now, I’d like to take a step beyond the discussion of this paper. Ask yourself, if you lived on the east coast of the United States and took a night drive and saw mammals on the road, which mammals would you most likely see? If you’ve been paying attention to your night drives, you should recall that although Coyotes, Foxes, Panthers/Mountain Lions, and dozens of other mammal species can potentially be seen on a night drive there are two that rule the night in terms of numbers: the Virginia Opossum (Diadelphis virginanus) and the Raccoon (Procyon lotor.)

Forget about the Opossum for a minute: what do we know about the Raccoon? Well, as any person who has herped, camped, hunted, fished, hiked, picnicked, or done just about anything outside will tell you, these little animals are mischievous, smart and really good at finding food. In fact, numerous studies cite Raccoons as the number one predator of many Reptile eggs, especially Sea Turtles.

Now, here’s an ecological concept we call a “Trophic cascade:” Burmese Pythons eat Raccoons, Raccoons eat turtles and their eggs. So what happens when we get more Burmese Pythons? They eat more and we have fewer Raccoons. What happens when we have fewer Raccoons? They eat less and we have more turtles/eggs.

 

So, most people will not dispute that Burmese Pythons are a invasive species, can and will have adverse effects to their South Floridian prey, and may be present in very high numbers (I’ve found about 55, personally.) So the question is this: might this “plague” on Florida actually be helping to protect their ectothermic brethren? Might the Pythons be a detriment on the 8 or so threatened and endangered Mammals occurring in their range but a help to the 17 threatened and endangered reptiles? Don’t get me wrong: pythons should not be here, and best management practices should be used to try to control their numbers – but maybe, especially for Reptile and Amphibians fans, every Burm has a silver lining.

 
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Posted by on 23/06/2012 in Exotic South Florida series

 

Exotic South Florida Part III: The Oustalet’s Chameleon (Furcifer oustaleti) in Florida

Some new stuff coming soon, including some more equipment reviews, but this for now: a few pictures and narrative on the invasive Oustalet’s Chameleons that are established in Dade County, FL.

The second species “officially” recognized (published) in the family Chameleonidae in Florida, though as many as half a dozen or more species of Chameleon are likely present/established in Florida.

Chameleons are good candidates for invasive species in Florida, because many species are hardy and can thrive here, and they are common and valuable in the pet trade. This has lead to a number of collectors setting up “ranches” or “Cash crops” of them in various areas, only to return in later years and collect free, healthy offspring of the original seeds.

Although it is easy to point the finger at these collectors, it’s also advisable to remember that most of these populations were likely started before there was general public knowledge of the harm that invasive species can cause to an ecosystem. That said, the issues with Chameleons in Florida are many: especially given that many of the populations are on private land and because of their monetary value some individuals will trespass and cause landowners to become hostile, often even to law abiding herpers/biologists/collectors/etc. who search from the road.

That silliness aside, on to some Oustalet’s ecology!


The population in Dade is likely pretty widespread, because Oustalet’s are known to cover a lot of ground when they decide to disperse. They will eat (almost) anything they can fit into their mouth, and considering they grow to be tied for the largest chameleon species, that’s quite a bit – including small birds. Here’s a adult male for size reference:

They are most definitely “beefy” chameleons, and like most chameleons grow extremely quickly. I’m personally amazed at how they’ve done so well in Dade County considering their egg incubation time is nearly a year! One would think that fire ants, torrential rains or bitter drought would overcome the clutch at some point during the year. Their clutch size can easily be up to and over 60 eggs.

In their native range (Madagascar) they primarily inhabit ecotones (edge habitats) and disturbed areas – which happens to be their primary haunts here in Florida as well.

Efforts are underway, spearheaded by FWC, to assess the impact of this species in Florida. Fortunately, this species seems to survive a lot better in disturbed (read: already screwed-up) areas than in pristine habitat, but more study will be needed to be certain.

 

Exotic South Florida Part II: The Genesis of the Burmese Python

Until the past 5 years or so, the Burmese Python (Python molurus bivittatus) wasn’t a part of the usual megafauna thought of in reference to South Florida. That’s all changed over the past couple of years thanks to a plethora of news stories, National Geographic specials, proposed bans and supposed experts.

I have a deep interest in these animals and have undertaken countless field hours to learn more about their ecology; and have published my findings both in an academic journal (“An effect of Burmese pythons. (Python molurus bivittatus) on mammal populations in southern Florida” Published in Florida Scientist, 2011), as well as an extensive section in my upcoming field guide.

The most common question I get from people in reference to the pythons is something along the lines of: “So, these are people’s pets crawling around that they let go?” I’m afraid not. Though the Pythons very likely came from the pet trade, the current profusion in Florida’s Everglades are individuals hatched and raised among the sawgrass, cypress and hardwood hammocks: not ever pets themselves. That said, there’s three main theories on where these animals came from, and I’ll mention them all currently:

The Pet Theory – The one regular touted by those with superficial python interest: newscasters, politicians and the general public (No offense to the general public, just most people’s lives aren’t affected by pythons too much.) The theory goes that a bunch of people over the years have bought cute little 1.5 – 2 foot long Burmese Pythons which fed happily on mice, only to find themselves with a 8 foot snake a year later. Being outside of the tolerance for most pet owners, and curiously eying ‘Mittens,’ the family cat; these animals were dumped in the the Everglades and eventually found other pythonic cast-offs and got together and had lots of babies and lived happily ever after.

There’s a couple problems here though: There’s an ecological concept called the “Minimum Viable Population” (MVP) which states that there must be a certain number of individuals to find each other and have a sustainable population. It’s unlikely that there were enough pythons released in one area to reach the MVP: according to Traill et al. (See citation below) the median (average) MVP for published species is 4169 individuals. That’s a lot of irresponsible pet owners. That said, given there large clutch size and a number of other factors, the MVP is likely a lot lower for Burmese Pythons; but suffice to say it’s probably more than a couple individuals.

One other issue is that the pythons started originally showing up at Flamingo – an area of Everglades National Park (ENP) at the extreme southern tip of the peninsula and a 40 mile drive from the entrance. So, in order to buy this theory, one would either have to contest that the python population started at Flamingo, or they would have to believe that an irresponsible pet owner, not willing to care for their snake any longer drove two hours to the extreme south of ENP instead of dumping it at the first patch of sawgrass they saw. A little bit of a stretch, in my humble opinion.

The “Hurricane Andrew” Theory – Getting a little more plausible here. This theory gets over the problem of the MVP by stating that reptile importers in Miami and Homestead lost hundreds (if not thousands) of Burmese Pythons when Hurricane Andrew hit in 1992. In fact, we do know for certain that Burmese pythons were lost in this storm: I seem to recall that even Miami Metrozoo lost a couple. But there still remains the belief that the population started in Flamingo. If the python population did start at Flamingo, I find it more than a little unlikely that the hundreds of escaped Burms migrated 50 or 60 miles from Homestead and Florida City before starting a breeding colony. Now, it is entirely possible that the original population was not from Flamingo, but the first sightings were all in that area so the evidence strongly suggests it. Additionally, Hurricane Andrew occurred in August, which means any escaped pythons would have around 6 months to disperse before the breeding season begins, around February, making finding each other to breed more difficult.

The “Ranch” or “Cash Crop” Theory – It’s only in the last few years (and owing a lot to the pythons) that exotic and invasive species are something which is on the radar of the general public, or even those who breed reptiles. Many times in the past, animals have been released by importers, breeders, or pet shops in order to establish a “ranch” the animals: it means free food and often times the animals will breed prolifically in the wild; allowing the offspring to be collected at a later date. This has been done with a number of species in Florida’s past (see Gillette, et al.), and I believe is likely the case with the pythons. It explains why a.) the pythons might have had their genesis at Flamingo, as well as b.) how enough pythons “met up” to sustain a MVP: a purposeful release could have included large, gravid females and other adults which would have been able to reproduce quickly.

Here’s another shot of that 4.43 meter female I found 2 years ago. Myself and my friend Donald. One of many we’ve found in the ‘Glades:

Gillette, C.R., K.L. Krysko, J.A. Wasilewski, G.N. Kieckhefer III, E.F. Metzger III, M.R. Rochford, and D. Cueva. 2010. Oustalet’s Chameleon, Furcifer oustaleti (Mocquard 1894) (Chamaeleonidae), a Non-indigenous Species Newly Established in Florida. IRCF Reptiles & Amphibians 17:248-249.

-Traill LW, Bradshaw JA, Brook BW (2007). “Minimum viable population size: A meta-analysis of 30 years of published estimates”. Biological Conservation 139 (1-2): 159–166.