Why Are Florida Mangroves Dying?
by Nick Hammond on Apr 29, 2022
Mangroves are an important coastal ecosystem in Florida that provide many benefits, including protecting the coastline from storm surge and erosion, providing nursery habitat for many marine species, sequestering large amounts of carbon, and filtering pollutants from water. However, in recent years, there have been concerning reports of mangrove die-offs and declines in parts of Florida due to several interacting factors.
Climate Change and Sea Level Rise
Rising global temperatures and changing rainfall patterns associated with climate change are putting stress on mangroves in Florida. Mangroves are very sensitive to changes in temperature, precipitation, and hydrology. Increased drought due to climate change can cause dieback and mortality. At the same time, sea level rise leads to increased saltwater intrusion into coastal wetlands. Mangroves have some tolerance for salt, but excessive salinity can cause physiological damage, nutrient deficiencies, and death. Areas where coastal development prevents inland migration are at highest risk of mangrove loss from sea level rise.
Runoff from urban and agricultural areas brings excess nutrients, pesticides, herbicides, and other pollutants into mangrove ecosystems. This can create conditions of low oxygen, algal overgrowth, and contamination that are toxic to mangroves. Sewage discharge, urban stormwater, and agricultural runoff add excess nitrogen and phosphorus that harm mangroves. Pesticides and other chemicals damage plant tissues, impair growth, and weaken mangrove defenses. Oil spills related to boating and coastal industry can also smother and poison mangroves. Heavy metals and other contaminants from industrial discharges accumulate in sediments, killing mangroves over time.
Development and Habitat Loss
Coastal development has destroyed and degraded much of Florida's original mangrove habitat. Urban expansion, construction of houses and resorts, and creation of marinas has directly removed mangrove forests. Additionally, development alters hydrology and interrupts sheet flow of water into wetland areas. Filling of wetlands for agriculture and construction eliminates important nursery habitat for fish and wildlife. Coastal armoring with sea walls and bulkheads prevents inland migration of mangroves as sea levels rise. Loss of mangrove buffer habitat leads to increased coastal erosion.
Changes in Freshwater Flow
Construction of dams and water diversion for human uses reduces freshwater flow into mangrove estuaries. This allows saltwater to advance further upstream, increasing salinity beyond mangrove tolerance. Lack of regular flushing also causes pollutants to accumulate in mangrove sediments. Hydrologic modifications that reduce sheet flow into mangroves can starve root systems of oxygen. Mangrove mortality has been linked to areas with reduced freshwater inflows.
Several invasive species threaten Florida's mangroves. The burrowing isopod and mangrove tree crab damage root systems, causing canopy dieback and mortality. Diseases like the red ring fungus have contributed to past mangrove declines and could reemerge as threats. Restoring natural hydrology, preventing pollution, and controlling non-native species will be key to mangrove conservation.
Protecting remaining mangroves and restoring degraded habitat will be essential to prevent further mangrove loss in Florida. Mangroves are ecologically and economically valuable ecosystems worth preserving for future generations through thoughtful coastal management.
When you purchase from MANG you join a movement of people who are banded together to protect, preserve and restore our ecosystems. The future depends upon stewards like you stepping up to the cause to protect our Earth today.