Reintroduction of Florida semaphore cactus to Florida Keys
David Bender is the type of guy who doesn’t mind getting his hands dirty, in fact, he wants to - - as long as plants are involved, particularly those that are threatened or endangered.
In May 2014, Bender, a botanist with the South Florida Ecological Services Office, traveled to Crocodile Lake National Wildlife Refuge and National Key Deer Refuge in the Florida Keys with co-workers Anthony Sowers and Brian Powell to plant 350 Florida semaphore cacti.
“We chose the refuges because public federal lands, especially national wildlife refuges and national parks, offer the best protection for listed plants,” Bender said.
Due to concerns about storm surge and sea level rise, their strategy was to plant the cacti in areas of higher elevation in suitable habitat that gets enough sunlight. In addition, they wanted to plant them in areas where there’s not too much human traffic.
“Elevation is a big factor. Twelve feet could make a difference in whether these cacti are gone in 30 years or will last another 100. These are some of the more critically endangered plants we have in South Florida,” Bender said of the cacti, which were listed as endangered in November 2013. “This plant is facing a number of threats, and there are only two known wild populations. That’s why we’re concentrating on reducing the threats that we can affect, but at the same time establishing new populations.”
Among those threats are storm surges and sea level rise that wreak havoc with the coastal habitats where these plants are found, and to a lesser degree poaching. Another is a non-native moth that was introduced to the area for biological control of similar cacti. unfortunately, this moth also feeds on Florida semaphore cacti.
“These moths are pretty wide ranging, so no matter where we planted these cacti, there was the possibility of them being a problem,” Bender said.
But fortunately, the moths haven’t yet turned out to be a show-stopping issue in this case. Bender and Sowers put 200 of the cacti in the ground at Crocodile Lake and 150 at Key Deer. So far, only a few of the newly-planted cactus have shown signs of moth damage.
During subsequent trips to monitor these plants, Bender says the survival rates at Crocodile Lake are around 98 percent after about one year, which he adds is “phenomenal.” At Key Deer, however, the survival rate is around 86 percent. “I’m pretty sure most of the losses there were due to the moth.”
Bender returns to the sites to check on these cacti every six months or so, and will do so for the next year or two. So far, he’s encouraged that most of the cacti they planted will survive.
“It’s still too soon to know for sure, but this reintroduction effort has already worked better than others I’ve seen at the one-year mark. Time will tell,” Bender said.
Sowers, now with the Coastal Georgia Ecological Services Office, hasn’t been back to the sites since planting these cacti, but says he enjoyed working with Bender and that Bender keeps him posted. “The most challenging aspect of the planting was finding suitable areas on the rocky landscape. It wasn’t as easy as digging a hole in the dirt and throwing in some potting soil,” he said.
“Dave is an easy guy to work with. He’s well organized and knows his stuff. We had a lot of fun, but got a lot of work done in a short period of time,” Sowers added.
It’s obvious that this is an effort Bender cares about deeply. “Reintroducing a plant species and re-establishing a population in its native range- -that will hopefully be self-sustaining- -is extremely satisfying and a legacy worth putting my energy into,” he said.
In the meantime, Bender hopes to do more work on imperiled South Florida plants that gets his hands dirty. “Field work is life! I’m always game for getting out of the office and doing something on the landscape,” he chuckled.
Dana Hartley, leader of the South Florida Ecological Services’Endangered Species Team, said, “This project is highly indicative of what a forward-thinker Dave is on the effects of climate change and sea level rise on these plants. He’s leading the effort that’s buying this species some very valuable time.”
Ken Warren, USFWS
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