Mangroves in Florida Expanding Due to Climate Change

Fewer cold snaps in Florida are helping mangroves extend their territory, according to a new study.

Mangroves thrive in warm, salty areas and are known to form complex ecosystems. Their presence in the Sunshine State was limited due to freezing temperatures during winter. However, from the past few years, there has been a decline in the number of days that see temperatures dipping below negative 4 degrees Celsius (25 degrees Fahrenheit).

Fewer cold days have led mangroves to getting a foothold in the region.

"Before this work there had been some scattered anecdotal accounts and observations of mangroves appearing in areas where people had not seen them, but they were very local," said study lead author Kyle Cavanaugh, a postdoctoral researcher at Brown University and at the Smithsonian Institution, according to a news release. "One unique aspect of this work is that we were able to use this incredible time series of large scale satellite imagery to show that this expansion is a regional phenomenon. It's a very large scale change."

Marching Forward

The study team didn't just document the rise of the mangroves in Florida, but even tried to assess the factors that helped these forests thrive.

The team, along with researchers at the University of Maryland, ruled out major contributors such as rise in the annual mean temperature, land use and rainfall.

Researchers then focused on cold snaps, the days that see a brief dip in temperature. Daytona Beach experienced just 1.4 fewer cold snaps between 1984 and 2011 while Titusville had just 1.2 days a year that saw the mercury levels drop below freezing point. The scientists found that these subtle changes were enough to explain the doubling of mangrove in these areas.

The study is published in the journal Proceedings of the National Academy of Sciences.

Variation in Florida's climate has led to significant changes in the state's coastline, researchers said. Coastal takeover by mangroves isn't a good sign. Researchers have pointed out that these forests are invading salt marsh that is a natural habitat of many organisms.