Wednesday, November 04, 2009

Refuge's new philosophy: Kill palms, save panthers

November 3, 2009

Federal stimulus dollars supporting the effort

by kevin lollar

What we have here is an environmental irony.

State and federal agencies spend millions of dollars to get rid of non-native plant and animal species, and now the U.S. Fish and Wildlife Service has received $171,094 in stimulus funds to remove native cabbage palms - the state tree of Florida, no less - from the Florida Panther National Wildlife Refuge.

"I've been getting crap about this because it sounds so stupid, cutting native trees," refuge biologist Larry Richardson said. "This is really a lesson in fine-tuning our vision. Just because a plant is a native doesn't mean it can't get out of control."

The key phrase here is "out of control": Cabbage palms have gotten so dense in some places - up to 1,200 trees per acre - that they're shading out such plants as American beautyberry, saltbush and partridge pea, which are important food for deer.

Deer, in turn, are important food for the endangered Florida panther, so less deer food means less deer, which means less panther food.

"The thing I've seen flying over Southwest Florida in the past 25 years is a tremendous growth of cabbage palms into open habitats," said Darrell Land, Florida

refuge: too many cabbage palms

Vehicles have killed three Florida panthers since Oct. 19, including a female kitten hit Sunday on County Road 833 in Collier County.

Fish and Wildlife Conservation Commission Panther Team leader. "The cabbage palms come in thicker than hair on a dog's back, so you lose that ground cover that deer and other animals survive on, and the habitat loses the ability to support prey items.

"Panthers don't photosynthesize. They can't live on air. They need meat to eat, and if there's no meat, they'll go elsewhere, which could put them in competition with other panthers."

Taken farther, Land said, if cabbage palms get out of control on a large enough scale, the panther population - which is about 100 - might start to decline.

Just as blame for non-native plants, such as melaleuca and Brazilian pepper; and non-native animals, such as Nile monitors and Burmese pythons; can be laid on humans, so can the proliferation of cabbage palms.

For cabbage palms, it's all about changes in hydrology: For decades, people have dug canals and ditches to drain South Florida, so many areas that once were covered with water during the wet season are dry all year.

Under normal wet-season conditions, cabbage palm seedlings died in the standing water, but now that the historically wet areas are dry, more cabbage palms are growing up.

"I've been here for 20 years, and I watched 6-inch tall cabbage palms turn into an impenetrable barrier," Richardson said. "There's been an exponential explosion of cabbage palms. So they've taken over the forest - you can't see the forest for the cabbage palm trees."

Panthers aren't the only issue when cabbage palms take over.

South Florida evolved as a fire-dependent environment: In the pre-canal world, lightning started fires, which burned dead vegetation, while vegetation such as slash pines and cabbage palms burned but survived.

These days, the fire regime has been altered in areas where cabbage palms have become very dense.

"Cabbage palms love to burn," Richardson said. "Slash pines can take the heat, but when you get pines surrounded by palms, the palms become a torch, and the pines die. Then the palms bud new leaves, and they're fat and sassy.

"So the upland pine flatwoods become cabbage palm hammocks, which are very unproductive."

Canals and ditches have also lowered water levels in area aquifers, and they flush water that would normally stay in wetlands to west coast estuaries.

So far, Wildland Services Inc. of Moore Haven has removed cabbage palms from a large portion of the refuge's east side and is working on the west side. Crews cut trees taller than 6 feet and leave them in place to decay or to be burned by prescribed fires; smaller trees will be killed with herbicides.

"Where we've done so far, panthers love it, deer love it, orchids love it," Richardson said. "Red-cockaded woodpeckers have appeared since it's been cut. We're looking at them setting up light housekeeping."

Cabbage palms are a natural part of the refuge, so work crews are not removing every tree.

"We're getting it back to the density we had before," Richardson said. "Bottom line, this is a restoration project: I'm restoring the habitat to what it looked like in the '50s."

Which is fine, but the land will still be dry where it's supposed to be wet, so, Richardson said, fixing the hydrology is the next step.

Additional Facts

In all, Florida is receiving $6.54 billion in stimulus money for 1,846 projects. Lee County has 23 projects worth $119.5 million, and Collier has 18 projects worth $204.8 million.


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