Wood storks as ecological indicators
Although an endangered species, wood storks can still be spotted with regularity by knowledgeable South Floridians. A white feathered bird with black accents, a scaly unfeathered neck and head, and pinkish toes, the wood stork has an extensive range in the United States, but thrives in South Florida's wetlands, where the bird's tactile feeding methods -- also called grope feeding -- are more likely to succeed because of the concentration of prey. See, e.g., U.S. Fish & Wildlife Service, Multi-Species Recovery Plan for South Florida (1998) at 4-399. According to that U.S. FWS report, "the goal for wood stork recovery in South Florida is to support 2,500 nesting pairs in the Everglades and Big Cypress Basin systems and to support, as a South Florida ecosystem component, 35 percent (3,500 nesting pairs) of the southeast United States recovery and delisting nesting population of 10,000 pairs." Although those overall recovery numbers have not yet been reached, conservation officials have made substantial progress. According to the Florida Fish & Wildlife Conservation Commission, "a survey in 2002 showed that (South Florida) now contains between 6,600 and 7,700 nests in 41 colonies", numbers far better than the lows in the 1000-2000 range seen in the 1980s, but a far cry from historical estimates.
An important question, as often asked with endangered species, is why should we care? The answer, as often stated on these pages, is that each species is indicative of the quality of its environment, which in turn means the quality of life for humanity. And the improving condition of the wood stork may be evidence that things are getting better in South Florida.
Wood storks enjoying life in Georgia too, from GA Department of Natural Resources
Evidence of the role of the wood stork as an indicator species can be found throughout the world wide web. Consider, for example:
- Wood storks as evidence of coastal ecosystem health, including sea level rise. According to Department of Interior data published by Florida State University, "the wood stork is important as an indicator of the state’s coastal environmental health and the declining abundance of coastal habitat. The nesting substrate of wood storks consists of mangrove and cypress trees... Loss of or reduction in nesting substrate may result in a decline in nesting effort. Additionally, without the proper nutritional base to support nesting efforts, wood storks will not nest. Wood storks are dependent on tidal fish as their food source. A decline of wood stork nests in Florida’s coastal counties may be indicative of changing environmental conditions such as rising water levels, loss of nesting substrate, or fluctuations in the food supply."
- Wood storks as barometers of the Everglades. According to the University of Florida, IFAS, "the extreme dependence of the wood stork on a naturally functioning hydrologic regime of the southern Florida wetlands makes it an excellent indicator of the health of the Everglades. In fact the National Audubon Society calls the wood stork "the barometer of the Everglades."
- Wood storks as indicators of proper hydrology. According to Everglades National Park, "our understanding of the habitat requirements of wood storks makes it possible to revise water management practices in order to restore good wading bird feeding conditions. The challenge, however, is to implement these improved water management programs in the face of the rapidly growing human demands for water and space in southern Florida." See also, Steven M. Davis, Ecological Synthesis, available online from the South Florida Water Management District.
- Wood stork abundance as a modelling tool. The presence or absence of wood storks is used by the U.S. Geological Survey as an ecological indicator it its scientific models. See, USGS, "Spatial Decision Support Systems for Landscape Ecological Evaluations in the Southwest Florida Feasibility Study"
If wood storks are ecological indicators, then the signs are pointing towards an improving South Florida environment. According to the Five-Year Status Review published by U.S. FWS in 2007: "Since listing, the number of nesting pairs is increasing, the number of nesting colonies is increasing, and the nesting range is growing. Even though threats that affect wood storks appear to be continuing at the same levels, the conclusion is that the overall population status is improving." In addition, based on data from 2001-2006, nesting pair averages ranged from 7,400 to over 8,700, a conclusion that led to the recommendation to downlist the species from endangered to threatened.
People have come to think of "a visit from the stork" as a good thing. The logic applies to wood storks too. The next time you spot a pair of wood storks flying by, remember, that flight was a sign of good news.