National Geographic : 2014 Jul
0mi 50 0km 50 30°N 26° 25°15′N 29° 28° 27° Area surveyed Not surveyed FLORIDA ACRES OF MANGROVE FOREST IN 2011 AREA GROWTH SINCE 1984 3,324 3,720 10,848 2,021 18,793 +47.1% +16.1% - 3.7% - 4.0% +170.7% PHOTO: CARLTON WARD, JR. MAP: RYAN MORRIS, NGM STAFF. SOURCES: KYLE C. CAVANAUGH, BROWN UNIVERSITY AND THE SMITHSONIAN ENVIRONMENTAL RESEARCH CENTER; JAMES R. KELLNER, BROWN UNIVERSITY NEXT Uprooted Mangroves are on the march. In recent years scientists have observed the tangled trees growing farther north along Florida’s Atlantic coast, but it wasn’t until a team of U.S . researchers examined yearly satellite images that they real- ized the extent. From 1984 to 2011 mangrove forests doubled in size at the northern end of their Florida range. What’s enticing the man- groves north? Fewer cold snaps. These days temperatures rarely dip below 25°F, a vital threshold for the trees. “Small changes in temperature,” says researcher Kyle Cavanaugh, “can lead to landscape-scale changes in habitat.” — Rachel Hartigan Shea Forest expansion Mangroves respond quickly to climatic changes. When an area becomes hospitable, far- floating seedlings soon take root.