Thursday, Aug 21, 2014
Local News

Unwelcome invaders


Published:

SEBRING - Some of the unwelcome invaders climb. Others fly or jump. And some slither.

What they all have in common is they are considered invasive plants and animals.

Those who are fighting to control the plants and animals that have no local natural predators talk about plants that creep over trees, toads that secrete poisons and aquatic weeds that clog lakes.

James P. Waller, a veterinarian in Lake Placid, said his contact with invasive species involves the giant toad, Bufo mainus, also known as the marine toad or the cane toad, which excretes a poison that can kill dogs and cats.

"We see a lot of cases every year," he said.

According to Florida Wildlife Extension at the University of Florida, if a dog or cat bites the toad, the animal "secretes a highly toxic milky substance from its large paratoid glands at the back of its head."

Symptoms of that in pets include drooling, head-shaking, crying loss or coordination and possibly convulsions, the extension service's web site says.

Besides those symptoms, another sign is red gums.

Waller said those who suspect their pets were affected by the giant toad should rinse their mouth and gums with water.

"The quicker you can do that, the better chances the dog will survive," he said, adding that he's seen very few cases in cats.

Waller said he's found that smaller dogs are at higher risk of death than larger dogs.

When people bring their dogs, he said, he uses medications to counteract the toad toxin. He also makes sure the dog does not have high fever.

Waller advises that people keep their dogs inside at night to prevent been bitten.

It used to be that most of the cases involving the toads were in the south part of Highlands County, he said. "Now they seem to be about everywhere."

The University of Florida web site notes that the giant toad will eat all types of native frogs and toads and even pet food.

The toad is far from being the only non-native creature that has wreaked havoc on the local environment.

David Austin, a horticulturalist with the Highlands County Extension Service, said the ambrosia beetle, for example, kills avocado trees.

Anyone in Highlands County with such trees that are still alive are lucky, he said.

Many plants also create problems, both on land and in water, in Highlands County.

The world climbing fern lives up to its name by climbing up and over trees and growing so dense that native plants do not get the light needed to survive, said Cheryl Millett, a biologist with the Nature Conservancy in Polk County.

It also causes the trees to die, she said.

Another problem non-native plant that affects cattle ranches in Highlands County is Cogan grass, which is "very rough and unpalatable to cattle," she said.

The aggressive plant displaces other grasses and plants that the cattle normally eat, she said.

Tropical soda apple, which is not the fruit you find on grocery shelves, affects cattle ranches in the same way, by eliminating vegetation suitable for livestock to survive.

Melaleuca and Brazilian pepper have also become serious problems in Florida, Austin said.

In the water, hydrilla an aquatic weed, has become invasive in lakes in Florida, including Highlands County, Austin said.

Highlands County has worked to remove the weed that was originally used in aquariums. People dumped the weed and it made its way into waterways.

Officials say that many of the invasive species have started out as plants purchased for a garden or a pet that was abandoned after the owner didn't want it anymore. But invasives can arrive in other ways, Millett said.

A plant seed, for example, may end up in a suitcase without the owner's knowledge, she said.

She also heard a story about a Burmese python found in taxi cab from south Florida. If the python had escaped and found a mate, it could have multiplied, she said.

Starting out as a pet, the Burmese python, which has invaded South Florida, hasn't reached Highlands County -- or at least not in any significant numbers --, but citings have occurred in nearby Okeechobee County, Millett said.

While some people believe the python will not spread north of southern Okeechobee County, Millett said she's not counting on the cold weather to stop it.

The Highlands County Extension Service and the Heartland Cooperative Invasive Species Management Area work to educate people to help avoid the introduction of other new invasive species.

Millett said the management area was created to coordinate efforts to control invasive species in Highlands, Polk, DeSoto and Hardee counties.

On Oct. 16 at Archbold Biolgical Station in Venus, a workshop will help people distinguish between native and invasive grasses. Anyone wanting to attend can register at grassowrkshop101613.eventbrite.com.

The best way to deal with invasive species is to prevent them from coming to an area, Millett said.

"The most expensive and least effective method of dealing with invasive exotic species is control, because at that point the species is already well established and likely cannot be eradicated, but can only be managed to be less of a problem," she said.

A secondary approach is for there to be a rapid response to citings of invasive species, she said. There may be some hope at that point of eliminating the invasive species,.

Currently, she said, people are on the watch for several invasive plants found in other counties, but not in this area or not in significant quantities.

The species watched locally, either in low numbers, or in case they arrive here, include the following:

Nandina domestica is a shrub that forms dense groves, which replaces natural vegetation.

Bowstring hemp is a perennial with greenish-white flowers that has increased in abundance, but has yet to be destructive to native plants. Melaleuca is an evergreen tree that displaces native plants and reduces the food supply for animals.

Kudzu is a high-climbing vine that can completely engulf unwooded areas and envelope trees, killing the trees by shutting out light.

Chinese privet is a shrub that can threaten other plants, including the endangered Miccosukee gooseberry.

Oyster plant is a perennial herb that formes a dense ground cover, preventing other native plants from growing.

jmeisel@highlandstoday.com

(863) 386-5834

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