Tree–Grass Coexistence in the Everglades Freshwater System
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Mosaic freshwater landscapes exhibit tree-dominated patches —or tree islands—interspersed in a background of marshes and wet prairies. In the Florida Everglades, these patterned landscapes provide habitat for a variety of plant and animal species and are hotspots of biodiversity. Even though the emergence of patchy freshwater systems has been associated with climate histories, fluctuating hydrologic conditions, and internal feedbacks, a process-based quantitative understanding of the underlying dynamics is still missing. Here, we develop a mechanistic framework that relates the dynamics of vegetation, nutrients and soil accretion/loss through ecogeomorphic feedbacks and interactions with hydrologic drivers. We show that the stable coexistence of tree islands and marshes results as an effect of their both being (meta-) stable states of the system. However, tree islands are found to have only a limited resilience, in that changes in hydrologic conditions or vegetation cover may cause an abrupt shift to a stable marsh state. The inherent non-linear and discontinuous dynamics determining the stability and resilience of tree islands should be accounted for in efforts aiming at the management, conservation and restoration of these features.
KeywordsTree islands Peatland Tree–grass coexistence Alternative stable states Resilience Savanna State shift
Support from the National Park Service (Everglades National Park #H5284080004) is gratefully acknowledged. This manuscript has greatly benefited from comments provided by Dr. Laurel G. Larsen and Dr. Judson W. Harvey, an anonymous reviewer, and the subject editor, Dr. Donald DeAngelis.
- Armentano TV, Jones DT, Ross MS, Gamble BW. 2002. Vegetation pattern and process in tree islands of the southern Everglades and adjacent areas. In: Sklar FH, van der Valk A, Eds. Tree islands of the everglades. Dordrecht: Kluwer. p 225–81.Google Scholar
- Borgogno F, D’Odorico P, Laio F, Ridolfi L. 2009. Mathematical models of vegetation pattern formation in Ecohydrology. Rev Geophys 47:RG1005. doi: 10.1029/2007RG000256.
- Brandt LA, Silveira JE, Kitchens WM. 2002. Tree islands of the Arthur R. Marshall Loxahatchee National Wildlife Refuge. In: Sklar FH, Valk Avd, Eds. Tree Islands of the Everglades. Dordrecht: Kluwer Academic Publishers. p 311–35.Google Scholar
- Brown S, Gillespie AJR, Lugo AE. 1989. Biomass estimation methods for tropical forests with applications to forest inventory data. For Sci 35(4):881–902.Google Scholar
- Craighead FC. 1971. The trees of south Florida. Volume 1: the natural environments and their succession, University of Miami Press, Coral Gables, FL., 212 pp.Google Scholar
- Davis SM, Gunderson LH, Park WA, Richardson JR, Mattson JE. 1994. Landscape dimension, composition, and function in a changing Everglades ecosystem. In: Davis SM, Ogden JC, Eds. Everglades: the ecosystem and its restoration. Delray Beach (FL): St. Lucie Press. p 419–44.Google Scholar
- Frederick PC, Powell GVN. 1994. Nutrient transport by wading birds in the Everglades. In: Davis SM, Ogden JC, Eds. Everglades: the ecosystem and its restoration. Delray Beach (FL): St. Lucie Press. Google Scholar
- Glaser PH. 1987. The Ecology of Patterned Boreal Peatlands of Northern Minnesota: a Community Profile. U.S. Fish and Wildlife, Serv. Rep., Report 85 (7.14), Washington, DC.Google Scholar
- Kwon H-H, Lall U, Moon Y-I, Khalil AF, Ahn H. 2006. Episodic interannual climate oscillations and their influence on seasonal rainfall in the Everglades National Park. Water Resour Res 42:W11404. doi: 10.1029/2006WR005017.
- Khalaf FI, Misak R, Al-Dousari A. 1995. Sedimentological and morphological characteristics of some nabkha deposits in the northern coastal plain of Kuwait, Arabia. J Arid Environ 29(3):267–292, ISSN 0140-1963.Google Scholar
- Lago ME, Miralles-Wilhelm F, Mahmoudi M, Engel V. 2010. Numerical modeling of the effects of water flow, sediment transport and vegetation growth on the spatiotemporal patterning of the ridge and slough landscape of the Everglades wetland. Adv Water Res. doi: 10.1016/j.advwatres.2010.07.009.
- Larsen LG, Harvey JW. 2010. Modeling of hydroecological feedbacks predicts distinct classes of landscape pattern, process, and restoration potential in shallow aquatic ecosystems. Geomorphology. doi: 10.1016/j.geomorph.2010.03.015.
- Luken JO, Billings WD. 1985. The influence of microtopographic heterogeneity on carbon dioxide efflux from a subarctic bog. Holarctic Ecol 8:306–12.Google Scholar
- Mitsch WJ, Gosselink JG. 2000. Wetlands. New York: Wiley.Google Scholar
- Orem WH, Willard DA, Lerch HE, Bates AL, Boyland A, Comm M. 2002. Nutrient geochemistry of sediments from two tree islands in Water Conservation Area #B, the Everglades, Florida. In: Sklar FH, van der Valk AG, Eds. Tree islands of the Everglades. Dordrecht: Kluwer Academic Publishers. p 153–86.Google Scholar
- Richardson CJ. 2009. The Everglades: North America’s subtropical wetland. Wetlands Ecol Manage. doi: 10.1007/s11273-009-9156-4.
- Richardson CJ. 2000. Freshwater wetlands. In: Barbour MG, Billings WD, Eds. North American terrestrial vegetation. Cambridge: Cambridge University Press. p 449–98.Google Scholar
- Ridolfi L, Laio F, D’Odorico P. 2008. Fertility island formation and evolution in dryland ecosystems. Ecol Soc 13(1):5.Google Scholar
- Sah JP. 2004. Vegetation structure and composition in relation to the hydrological and soil environments in tree islands of Shark Slough. Chapter 6. In: Ross MS, Jones DT, Eds. Tree Islands in the Shark Slough Landscape: interactions of vegetation, hydrology and soils. Final Report submitted to Everglades National Park, U.S. Department of the Interior, National Park Service.Google Scholar
- Sarmiento G. 1984. The Ecology of Neotropical Savannas. Cambridge (MA): Harvard University Press.Google Scholar
- Science Coordination Team (SCT). 2003. The role of flow in the everglades ridge and slough landscape, South Florida Ecosystem Restoration Working Group, 62 pp.Google Scholar
- Sklar FH. 2001. In: Kloor K, Eds. Forgotten Islands, Audubon Magazine, July–August.Google Scholar
- Sklar FH, van der Valk A, Eds. 2002. Tree islands of the Everglades. Dordrecht: Kluwer Academic Publishers. p 541.Google Scholar
- Walker BH, Noy-Meir I. 1982. Aspects of stability and resilience of savanna ecosystems. In: Walker BH, Huntley B, Eds. Ecology of Subtropical Savannas. Berlin: Springer. p 556–90.Google Scholar
- Walter H. 1971. Ecology of tropical and subtropical vegetation. Edinburgh: Oliver and Boyd.Google Scholar
- Wetzel PR. 2002. Analysis of tree island vegetation communities. In: Sklar FH, van der Valk A, Eds. Tree Islands of the Everglades. Dordrecht: Kluwer Academic Publishers. p 357–89.Google Scholar