In the decade since the U.S. Fish and Wildlife Service added the rare Florida bonneted bat to its endangered species list, a trove of information has helped better identify the bats’ habits and zeroed in on one particularly important spot: the sprawling parking lot around Zoo Miami.
Much of the data came from an award-winning conservation program started by the zoo in 2018 with Bat Conservation International and funded by Florida Power & Light.
Over three years, as federal regulators worked to determine the contours of critical bat habitat, a team of scientists, conservation groups and volunteers erected bat houses and strung recorders in areas where the high-flying bats are likely to roost and hunt for food. Houses went up on the Granada golf course in Coral Gables, near Fairchild Tropical Garden and near the zoo, erected on a Navy old blimp base tucked into pine rocklands in southern Miami-Dade.
Hours of recordings revealed that the rare bats that inhabit the disappearing rocklands had carved out an oasis over the parking lot, eating, socializing and raising babies.
“Our data shows that the highest density population is on that property,” said Melquisedec Gamba-Rios, a bat biologist with Bat Conservation International. “If we lose all that open space to any kind of development, we're going to lose that core of the population.”
Those findings came amid stepped up efforts by developers’ to build an Orlando-style theme park on the parking lot which unraveled this month.
On Tuesday, Miami-Dade county commissioners will again consider revising a lease for a scaled-back version that was deferred earlier this month. But court papers filed Friday suggest that vote may again be postponed indefinitely.
The deal was initially approved in 2020 but derailed after federal officials admitted in a February lawsuit that they’d failed to complete required wildlife studies on land previously owned by the National Park Service. The land came with deed restrictions put in place in the 1970s when the U.S. government gave the land to Miami-Dade. Miami-Dade County officials offered to amend the lease to give federal officials time to complete the studies.
Late last week, Commissioner Kionne McGhee asked that the vote be deferred to an uncertain date, according to a court status report filed Friday. If deferred, the report said, county officials say they may then ask to file a separate case against Miami Wilds.
While the rare pine rocklands have driven most of the debate around conservation near the zoo, the presence of the bats has proved the most controversial.
In May, Miami-Dade County removed Bats Conservation from the permit allowing the research work, effectively sidelining Gambas-Rios, the expert investigator. In an email, county officials said they removed the organization that co-founded the zoo’s bat lab over the lawsuit, which could jeopardize ongoing work. In the years since it was created, the bat lab had brought together more than a dozen conservation groups and a league of volunteers to work with state and federal wildlife officials to document bat habits and better understand how they could survive in South Florida’s busy urban neighborhoods.
“Due to an active litigation against the County,” the email said, “it was determined that it was not in the best interest of the County to approve the permit with the full list of individuals listed as certain individuals are associated with organizations that are a party to the ongoing litigation against the County.”
Meanwhile, Miami Wilds developers have pushed to draw attention to their own bat study, which they commissioned last year from Johnson Engineering.
“The controversy has really been stirred up by Bat Conservation International,” park architect and developer Bernard Zyscovich said on WLRN’s South Florida Roundup earlier this month. “The bottom line, the punch line, is the bonneted bats do not forage here.”
Zyscovich also complained that Bats Conservation International, despite working with zoo officials as part of the bat lab, failed to provide back-up information about their work to either the developers or county staff.
The study commissioned by developers, Zyscovich said, found just 3% of bat calls over the parking lot came from endangered bonneted bats and cited surveys done by zoo officials between 2012 and 2013 as confirming the developers’ findings.
However, Gamba-Rios and published research from the earlier zoo study, show the different surveys don’t accurately invite easy comparisons. The Bats Conservation work spanned a far longer timeframe, included individual sounds and covered a larger area to paint of picture of how the big-winged bats inhabit the area. The zoo research was done a decade ago with less sophisticated equipment and before the bat lab’s conservation efforts attracted bats to a network of newly erected bat houses.
Zoo workers first discovered a dead bonneted bat near the elephant enclosure in 2004. In 2011, the year before the U.S. Fish and Wildlife Service considered adding the last of North America's largest bats to the endangered species list, the Florida Bat Conservancy conducted acoustic surveys with zoo staff hoping to document the bats. They found one, suggesting the rare bats might still be in the area. Three months later, the Service gave the zoo a grant and permission to record and study the bats.
In those earlier surveys, using less sophisticated equipment, the recordings detected a pattern to their activity. The bats seem to emerge from the pine rocklands, where they roost, after sunset and begin feeding over the parking lot and open areas near the zoo. The parking lot showed the highest concentration of calls.
The sprawling parking lot is used for zoo parking, but since the zoo is rarely open at night, it's mostly dark after sunset. The lot is also far bigger than what's needed, with a section of crumbling asphalt where some pineland plants grow.
“It is very important is not just to know where they want to sleep, but also where they going to eat,” Gamba-Rios said.
As part of the bat lab project, Gamba-Rios and zoo vet Frank Ridgley created bat houses specially designed for the big bonneted bats to roost. They began erecting them in areas where they would likely feed — large dark areas that provided unobstructed air space for the fast-flying bats to zoom after insects. They they started recording them.
“We installed multiple recorders all across Miami-Dade County because we want to identify areas where they're eating and and understand how they're using the different environments,” Gamba-Rios said. “Miami-Dade is in between an ocean and the Everglades, so it's really narrow and really restricted.”
What mattered to the bats when it came to foraging was the combination of pine rockland and nearby dark, open space, Gamba-Rios said, that mimicked the natural pinelands surrounded by open sawgrass prairies.
“You need to be thinking from their perspective. They don't care about what’s on the surface. Could be grass. Could be water. Could be concrete. It’s exactly the same for them,” he said. “The important part is that it's an open space next to trees, next to a forest that is going to provide the insects that they need to eat at night.”
The zoo parking lot, he said, provides the only setting like that in South Florida. Not only is it an open space largely unused and unlit, but it sits next to the largest tract of pineland outside the Everglades.
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“We don't need to protect all the parking lots in Miami? Definitely not. This parking lot or open area is just because it has unique characteristics,” he said.
Survey recordings found the parking lot has between 500 and 600% more activity than any other sites studied by the team.
“The open space and the darkness that are there you cannot find anywhere else in in the county,” he said. “So a lot of the bats probably are coming to feed, to have social activities, and then they disperse and go back toward their roosts.”
If it proceeds, Miami Wilds will be the second large project in the Richmond pine rocklands around the zoo and bat habitat. In 2013, county officials rezoned another chunk clearing the way for a shopping center and apartments and triggering a drawn-out legal battle with conservationists. Earlier this month, longtime zoo spokesman Ron Magill blasted the Miami Wilds project, saying he regretted not raising concerns over the strip mall.
Since the zoo started its conservation efforts and erected the bat boxes around the zoo, 100 bats have been confirmed roosting in them. That now makes the zoo bats the second largest known population and the most densely populated anywhere.
“They're not asking for much,” Gamba-Rios said, “just for one place, the last place, the last oasis that they have.”
