Rising sea levels threaten the diverse ecology of the Everglades.
Scott Leslie/Minden Pictures
Efforts to restore the rich ecology of the Florida Everglades have so far focused on fighting damage from pollutant runoff and reestablishing the natural flow of water. But now, an expert panel is calling for federal and state agencies to reassess their plans in light of threats from climate change and sea-level rise. A congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine, released on 16 October, asks the managers of the 18-year-old Comprehensive Everglades Restoration Plan (CERP) to conduct a “midcourse assessment.” The new evaluation should account for likely conditions in the wetlands in “2050 and beyond” and model how existing restoration projects would fare under various sea-level rise scenarios.
“I use the analogy of a hockey player,” says environmental economist William Boggess at Oregon State University in Corvallis, who is chair of the panel behind the new report. “Maybe we should be skating to where the puck is going to be rather than where it is right now.”
The Everglades watershed once included more than 1 million hectares of wetlands, sawgrass plains, and tree islands across southern Florida, but agriculture and human settlement have shrunk that habitat by half. Phosphorus from agricultural runoff has killed sawgrass that thrives in the Everglades’ naturally low-phosphorus conditions. In its place, dense cattail habitats have sprung up, choking off water access for animals and birds. Eighty plant and animal species in the larger region are now threatened or endangered.
CERP, established by Congress in 2000, is a multidecadal effort to restore and better manage the Everglades, jointly run and funded by the federal government and the state of Florida. For the past 5 years, they’ve been jointly putting an average of $230 million per year into CERP projects, including efforts to eradicate invasive exotic plants and restore water patterns of water flow through the wetlands.
But the new report points to a different set of concerns arising for the region: Sea levels have risen approximately 7 centimeters since 2000, and Southern Florida expects a 0.8-meter rise by 2100. Saltwater can have complicated and contradictory effects. It inundates plant life and degrades their roots, which promotes erosion, but it can also keep microbes from decomposing plant matter, which leads to a buildup of soil. Changing patterns of erosion and water surges could complicate CERP projects such as an effort to manage how fresh and saltwater are distributed across Biscayne Bay on Florida’s east coast.
To account for the impacts of climate change, CERP should incorporate the most recent climate models, and should appoint an independent “Everglades lead scientist,” the report says, to make sure these models inform all CERP projects.
Lake Okeechobee, the largest water source in the Everglades system, gets its own chapter in the report. The lake feeds estuaries and wetlands to the south, and is home to the Everglade snail kite, an endangered bird of prey. The report recommends closer monitoring and research on the lake’s levels to inform a new regulatory plan. Low water levels can minimize dangerous flooding and foster submerged vegetation. High levels, which ensure water for human use and natural preserves southward, also spread contaminants to cleaner shallow zones.
The report also discusses tentative plans to add nearly 350 million cubic meters of surface storage and 80 aquifer storage and recovery wells around Lake Okeechobee. That would help managers control water levels, notes ecologist Paul Gray, science coordinator for Audubon Florida’s Everglades restoration program in Lorida, who was not on the report committee. But competing demands on the water supply from communities, agriculture around the lake, and the wetlands to the south could complicate the management efforts, he says. “We are trying to restore a whole ecosystem, not just move the harm from one part of the ecosystem to another.”
Source: Science Mag