Hurricanes, Storm Surge, and Pine Forest Decline on a Low Limestone Island
Hurricanes are a frequent disturbance in the western Atlantic impacting coastal forest structure and persistence. This study addressed the hypothesis that periodic hurricane-associated winds and storm surges can interact with sea-level rise to cause the demise of coastal pine forests, based on the response of the Florida Keys’ last extensive tract of slash pine (Pinus elliottii var. densa) following Hurricane Irma (September 2017). Irma’s winds reached Category 4 strength in the study area on Big Pine Key, and storm surge flooded the island’s low limestone surface with salt water for the third time in 20 years, including Hurricanes Georges in 1998 and Wilma in 2005. Total mortality was 32% and was concentrated in the largest trees. Broken and uprooted trees that died immediately were distributed randomly across the elevation gradient, but trees without major stem damage that succumbed later occupied lower elevations. The extensive salt water flooding at low elevations was likely an agent of the mortality of slash pine, a fresh water–dependent species. Mortality due to Hurricane Irma contributed to a 1998–2018 decline in pine tree density and biomass of 74% and 80%, respectively. These dynamics were characterized by pine recruitment that was minimal in comparison with the three hurricane-driven mortality episodes. The data suggest that the 6 cm sea-level rise over the period exacerbated storm surge mortality by ponding salt water over more of the land surface, and the resulting scarcity of mature trees contributed to recruitment failure. In effect, the population declined at each disturbance, sea-level rise magnified these losses, and the local resilience of the population, i.e., its capacity to recover, was exceeded.
KeywordsSea-level rise Hurricanes Resilience Pine rocklands Islands Storm surge
We acknowledge the logistical support of the National Key Deer Refuge, especially to Dan Clarke, Christine Ogura, and Kate Watts. We are indebted to the students and technicians, too many to name here, without which this long-term research product would not have been impossible. Dean Whitman, Michael Kiflai, and Keqi Zhang were generous with their data and technical advice on groundwater and storm surge dynamics. This is contribution number 919 from the Southeast Environmental Research Center in the Institute of Water & Environment at Florida International University.
This work was supported by the National Key Deer Refuge (Cooperative Agreement Award No. F18AC00088).
- Cangialosi, J. P., A. S. Latto, and R. Berg. (2018). Hurricane Irma (30 August - 12 September 2017). Tropical Cyclone Reports, National Hurricane Center.Google Scholar
- Chambers, J. M., and T.J. Hastie. 1992. Statistical models in S. Wadsworth & Brooks/Cole. 624 pp.Google Scholar
- Ellison, A.M., M.S. Bank, B.D. Clinton, E.A. Colburn, K. Elliott, C.R. Ford, D.R. Foster, B.D. Kloeppel, J.D. Knoepp, G.M. Lovett, J. Mohan, D.A. Orwig, N.L. Rodenhouse, W.V. Sobczak, K.A. Stinson, J.K. Stone, C.M. Swan, J. Thompson, B. von Holle, and J.R. Webster. 2005. Loss of foundation species: consequences for the structure and dynamics of forested ecosystems. Frontiers in Ecology and Environment 3 (9): 479–486.CrossRefGoogle Scholar
- Francis, J.K., and A.J.R. Gillespie. 1993. Relating gust speed to tree damage in Hurricane Hugo, 1989. Journal of Arboriculture 19: 368–373.Google Scholar
- Gardner, L.R., W.K. Michener, E.R. Blood, T.M. Williams, D.J. Lipscomb, and W.H. Jefferson. 1991. Ecological impact of Hurricane Hugo - salinization of a coastal forest. Journal of Coastal Research 8: 301–317.Google Scholar
- Halley, R.B., H.L. Vacher, and E.A. Shinn. 2004. Geology and hydrology of the Florida Keys. In Geology and Hydrogeology of Carbonate Islands, ed. H.L. Vacher and T. Quinn, 217, 948–248. Elsevier.Google Scholar
- Kiflai, M., D. Whitman, D.E. Ogurcak, and M.S. Ross. In review. The effect of Hurricane Irma storm surge on the freshwater lens on Big Pine Key, Florida, using electrical resistivity tomography. Estuaries and Coasts.Google Scholar
- Little, S., J.J. Mohr, and L.L. Spicer. 1958. Salt-water storm damage to loblolly pine forests. Journal of Forestry 56 (1): 27–28.Google Scholar
- Ogurcak, D.E. 2015. The effect of disturbance and freshwater availability on lower Florida Keys’ coastal forest dynamics. FIU Electronic Theses and Dissertations. 2288.Google Scholar
- Ogurcak, D.E., and R.M. Price. 2019. Groundwater geochemistry fluctuations along a fresh-saltwater gradient on the carbonate islands of the lower Florida Keys. Chemical Geology. Google Scholar
- R Core Team. 2017. R: a language and environment for statistical computing. R Foundation for statistical computing, Vienna, Austria. URL http://www.R-project.org/.
- Reed, D.D., H.O. Liechty, and A.J. Burton. 1989. A simple procedure for mapping tree locations in forest stands. Forest Science 35 (3): 657–662.Google Scholar
- Robertson, W., and K. Zhang. 2007. Big pine key survey commissioned by the nature conservancy: Airborne LIDAR data and digital elevation models of Big Pine Key, Florida. Miami: International Hurricane Research Center Florida International University.Google Scholar
- Ruiz, P. L., M. S. Ross, and J. P. Sah. 2001. Population dynamics of Pinus elliottii var densa in Everglades Nation Park: a case for less frequent prescribed fire. Abstract. Natural Areas Association Conference. Cape Canaveral, FL. Oct. 2001.Google Scholar
- Sah, J.P., M.S. Ross, J.R. Snyder, and D.E. Ogurcak. 2010. Tree mortality following prescribed fire and a storm surge event in slash pine (Pinus elliottii var. densa) forests in the Florida Keys, USA. International Journal of Forestry Research 2010, Article ID 20495; 13 pp: 1–13. https://doi.org/10.1155/2010/204795.CrossRefGoogle Scholar
- Snyder, J.R., A. Herndon, and W.B. Robertson. 1990. Chapter X: South Florida rocklands. In Ecosystems of Florida, ed. R.L. Myers and J.J. Ewel, 230–277. University of Central Florida Press.Google Scholar
- Snyder, J.R., M. S. Ross, S. Koptur, and J. P. Sah. 2005. Developing ecological criteria for prescribed fire in South Florida pine rockland ecosystems. Open File Report OF 2006–1062, U.S. Geological Survey.Google Scholar
- Williams, K., Z. S. Pinzon, R. P. Stumpf, and E. A. Raabe. 1999. Sea-level rise and coastal forests on the Gulf of Mexico. Open File Report 99–441, U. S. Geological Survey.Google Scholar