Page 55

Bisbees Conservation Journal Q2 2015

BISBEE’S CONSERVATION JOURNAL Q2 • 2015 55 the value of mangrove wetlands and their contribution to the unique ecology and biodiversity of Mexico. In highly interactive classroom discussions, we learned that Mexico accounts for about 6% of the world’s remaining wetlands, or some 8.2 million acres. Much of the world’s wetlands—more than 60%—has been lost over the past 100 years, primarily through economic development and other human activities. In Mexico, the intertidal flats that comprise a sizable portion of the country’s wetlands provide habitat for more than 70% of North America’s wintering waterfowl species, including 84% of the continent’s Blue-winged Teal, 35% of all Redheads, and a significant percentage of all Northern Pintails and American Wigeon, along with six species of ducks that breed in Mexico, such as the Black-bellied Whistling duck. More than half of Mexico’s mangrove wetlands, including those that comprise the Ria Celestún Biosphere Reserve, can be found along the Gulf Coast. These wetlands are so important that the international Ramsar Convention on Wetlands named the Ria Celestún Biosphere Reserve a “wetland of international significance,” meaning the wetland has “significant value not only for the country, but for humanity as a whole.” So what is it about mangrove wetlands that make them so important? As we learned during the Mangrove Experience, wetlands in general are vital for flood control, clean water, and habitat for a multitude of species. In most areas they are also important for recreation. Mangrove wetlands, in particular, play a unique role in maintaining coastal ecosystem integrity and species diversity. Mangroves are adapted to tolerate salinity and low oxygen levels, and can withstand strong forces of nature such as hurricanes and floods, protecting dry land beyond. As Jorge Cerón, a young biologist and project supervisor with DUMAC, told us, the threats to mangrove wetlands in Mexico come from both natural and manmade forces. Tropical storms and hurricanes take their toll. But the more insidious and preventable threats to mangrove wetlands are those that are humancaused. Perhaps the most impactful force acting on the mangrove wetlands is economic development. About 60% of people in Mexico live in or adjacent to wetland habitats and, in a country with huge socioeconomic challenges, most kinds of economic development are welcome. Urban expansion, road construction, and the explosion of shrimp aquaculture in Mexico all take a toll on the wetlands. During our first field trip of the Mangrove Experience we saw firsthand the impact of road construction on mangrove ecosystems. Improperly constructed roads cut off the natural interchange of water between the estuary and the sea. The Yucatan peninsula has no natural freshwater rivers or lakes. Rainfall flows across the gently sloping topography through subterranean channels to the coasts. This fresh water nourishes lush inland and coastal vegetation, and, importantly, sustains the brackish coastal wetlands which are characterized by three species of mangroves—red, white and black—each less tolerant of saltwater than the next. Work being coordinated by Rogers Hoyt of DUMAC (left) and Peggy Sundstrom (center)


Bisbees Conservation Journal Q2 2015
To see the actual publication please follow the link above