The Current Policies and Research of Florida’s Mangroves

Mangroves are a critical player in Florida’s security from the elements, diverse balance of ecosystems, and natural beauty. While the issue of mangrove conservation is a recurring one in Florida politics, recent studies suggest that mangroves are expanding poleward in response to climate change. Mangrove poleward expansion is an undeniable reality, but its effects are not yet clear, indicating the need for further research as well as an effective monitoring and management plan. This literature review establishes how the study of mangroves and mangrove expansion has evolved over time, covering the evolution of mangrove legislation and scientific study in addition to relevant agreements and disagreements in the literature.

The legal centerpiece of Florida’s mangrove legislation is the Mangrove Trimming and Preservation Act of 1996.[1] This legislation was officially designed to “protect and preserve mangrove resources” from “unregulated removal, defoliation, and destruction.”[2] The statute is best used, however, alongside an article for the Florida Bar Journal by Kellyalexis Fisher, which reveals the key stakeholders and omissions from the statute. The original version of the law (1995) heavily favored Florida landowners, who sought to withdraw the power to regulate mangroves from local governments and make it significantly easier to trim mangroves without a permit.[3] While lawmakers revised the law in 1996 and partially tightened restrictions on mangrove trimming, the statute fails to fully address the concerns of Florida environmentalists and few adjustments have been made since.[4] The Florida Coastal Management Program Guide, while explaining coastal conservation, mentions climate change in only two sections.[5]

The scientific study of the effects of climate change on mangroves, on the other hand, has dramatically increased over time.  The first scientific article known to suggest a poleward mangrove expansion was published in 1991.[6] In the late 2000s and early 2010s researchers attributed poleward expansion to climate change.[7] Experts have identified that a major mechanism for the large northeast expansion observed in Florida is related to the decreased frequency of extreme cold events.[8][9] Researchers agree that the byproducts of climate change such as the increase in sea level and temperature are also directly affecting the distribution and performance of mangroves.[10][11] Experts have also identified that the decreased frequency in extreme cold events acts as a major mechanism for the mangrove expansion in Florida.[12][13]

Although experts collectively agree on the presence of poleward expansion, there is much uncertainty about the magnitude and potential outcomes of this phenomenon. Many raise concerns that this rapid spread could negatively impact ecosystems if remained unchecked.[14] For instance, mangroves are known to displace salt marshes, another ecologically valuable habitat.[15] There is also no consistent response of poleward mangrove expansion to temperature increase across the mangrove’s entire range.[16][17] The projected rate of expansion is highly variable across the different areas where some rates are negligible while others are predicted to increase significantly.[18] Researchers predict that mangrove ecosystems can keep pace with current rises in sea levels, but if sea levels continue to rise at an accelerated rate, mangrove habitats may collapse.[19][20] However, many argue that this expansion is beneficial because the ecosystem services provided by mangroves would only double. Mangroves are recognized for their vital contribution to ecosystem services such as providing buffer for coastlines, carbon storage, and habitat for many organisms. Some researchers predict that by 2080, mangroves could capture the equivalent of up to half of Florida’s yearly man-made carbon emissions.[21] As a result, many advocate that we should facilitate rather than impede the poleward march.[22][23]

Understanding the effects of climate change on mangrove ecosystems is important for developing an effective management plan to insure Florida’s future security, natural beauty, and ecological stability. Based on current mangrove legislation, this review finds that Florida law does not adequately address poleward expansion. Experts agree that poleward expansion is occurring throughout the mangrove’s range, however the consequences, rate, and magnitude of this habitat shift is still under dispute. With this in mind, we suggest a protected-study approach; expanding mangrove forests must be protected while future studies determine whether or not mangrove expansion will yield positive effects.

Bibliography

Cavanaugh, Kyle C. et al. 2014. “Poleward Expansion of Mangroves Is a Threshold Response to Decreased Frequency of Extreme Cold Events.” Proceedings of the National Academy of Sciences 111(2): 723–27.

Colin D. Woodroffe, and John Grindrod. 1991. “Mangrove Biogeography: The Role of Quaternary Environmental and Sea-Level Change.” Journal of Biogeography 18(5): 479–92.

Ellison, J, and D Stoddart. 1991. “Mangrove Ecosystem Collapse during Predicted Sea-Level Rise:Holocene Analogues and Implications.” 7: 151–65.

Florida Coastal Office. 2017. Florida Coastal Management Program Guide: A Guide to the Federally Approved Florida Coastal Management Program. Department of Environmental Protection. https://floridadep.gov/sites/default/files/FCMP-Program-Guide-2017_0.pdf.

Florida State Legislature. 1996. 403.9321-403.9333 403.9321 1996 Mangrove Trimming & Preservation Act. https://files.zotero.net/9561192967/A9RE616.pdf.

Jennerjahn, T. C. et al. 2017. “Mangrove Ecosystems under Climate Change.” In Mangrove Ecosystems: A Global Biogeographic Perspective, Springer, Cham, 211–44. https://link.springer.com/chapter/10.1007/978-3-319-62206-4_7 (February 3, 2018).

Jim Waymer. 2017. “Could Mangrove Northern Expansion Temper Global Warming?” Florida Today. https://www.floridatoday.com/story/news/local/environment/2017/01/14/could-mangrove-northern-expansion-temper-global-warming/94736686/.

Justin Gillis. 2013. “Spared Winter Freeze, Florida’s Mangroves Are Marching North.” New York Times. http://www.nytimes.com/2013/12/31/science/without-winter-freezes-mangroves-are-marching-north-scientists-say.html.

Kellyalexis Fisher. 1998. “Man Let ’em Grow: The State of Florida Mangrove Laws.” The Florida Bar Journal Volume LXXII(No. 5). https://www.floridabar.org/news/tfb-journal/?durl=/divcom%2Fjn%2Fjnjournal01%2Ensf%2FAuthor%2FDBAE001D7B30B37885256ADB005D61D5.

Meeder, John F., Randall W. Parkinson, Pablo L. Ruiz, and Michael S. Ross. 2017. “Saltwater Encroachment and Prediction of Future Ecosystem Response to the Anthropocene Marine Transgression, Southeast Saline Everglades, Florida.” Hydrobiologia 803(1): 29–48.

Osland, Michael J. et al. 2017. “Mangrove Expansion and Contraction at a Poleward Range Limit: Climate Extremes and Land-Ocean Temperature Gradients.” Ecology 98(1): 125–37.

Snedaker, S, and R Araujo. 1998. “Stomatal Conductance and Gas Exchange in Four Species of Caribbean Mangroves Exposed to Ambient and Increased CO2.” 49: 325–27.

On my honor I have neither given nor received unauthorized information regarding this work, I have followed and will continue to observe all regulations regarding it, and I am unaware of any violation of the Honor Code by others.

Footnotes

[1] Florida State Legislature, “1996 Mangrove Trimming & Preservation Act,” 403.9321-403.9333 403.9321 § (1996), https://files.zotero.net/9561192967/A9RE616.pdf.

[2] Kellyalexis Fisher, “Man Let ’em Grow: The State of Florida Mangrove Laws,” The Florida Bar Journal Volume LXXII, no. No. 5 (May 1998), https://www.floridabar.org/news/tfb-journal/?durl=/divcom%2Fjn%2Fjnjournal01%2Ensf%2FAuthor%2FDBAE001D7B30B37885256ADB005D61D5.

[3] Ibid.

[4] Ibid.

[5] Florida Coastal Office, “Florida Coastal Management Program Guide: A Guide to the Federally Approved Florida Coastal Management Program” (Department of Environmental Protection, October 11, 2017), https://floridadep.gov/sites/default/files/FCMP-Program-Guide-2017_0.pdf.

[6] Colin D. Woodroffe and John Grindrod, “Mangrove Biogeography: The Role of Quaternary Environmental and Sea-Level Change,” Journal of Biogeography 18, no. 5 (September 1991): 479–92.

[7] Justin Gillis, “Spared Winter Freeze, Florida’s Mangroves Are Marching North,” New York Times, December 30, 2013, http://www.nytimes.com/2013/12/31/science/without-winter-freezes-mangroves-are-marching-north-scientists-say.html.

[8] Kyle C. Cavanaugh et al., “Poleward Expansion of Mangroves Is a Threshold Response to Decreased Frequency of Extreme Cold Events,” Proceedings of the National Academy of Sciences 111, no. 2 (January 14, 2014): 723–27, https://doi.org/10.1073/pnas.1315800111.

[9] Jim Waymer, “Could Mangrove Northern Expansion Temper Global Warming?,” Florida Today, January 14, 2017, https://www.floridatoday.com/story/news/local/environment/2017/01/14/could-mangrove-northern-expansion-temper-global-warming/94736686/.

[10] T. C. Jennerjahn et al., “Mangrove Ecosystems under Climate Change,” in Mangrove Ecosystems: A Global Biogeographic Perspective (Springer, Cham, 2017), 211–44, https://doi.org/10.1007/978-3-319-62206-4_7.

[11] John F. Meeder et al., “Saltwater Encroachment and Prediction of Future Ecosystem Response to the Anthropocene Marine Transgression, Southeast Saline Everglades, Florida,” Hydrobiologia 803, no. 1 (November 1, 2017): 29–48, https://doi.org/10.1007/s10750-017-3359-0.

[12] Jennerjahn et al., “Mangrove Ecosystems under Climate Change.”

[13] Meeder et al., “Saltwater Encroachment and Prediction of Future Ecosystem Response to the Anthropocene Marine Transgression, Southeast Saline Everglades, Florida.”

[14] Justin Gillis, “Spared Winter Freeze, Florida’s Mangroves Are Marching North.”

[15] Justin Gillis, “Spared Winter Freeze, Florida’s Mangroves Are Marching North.”

[16] S Snedaker and R Araujo, “Stomatal Conductance and Gas Exchange in Four Species of Caribbean Mangroves Exposed to Ambient and Increased CO2” 49 (1998): 325–27.

[17] Jennerjahn et al., “Mangrove Ecosystems under Climate Change.”

[18] Michael J. Osland et al., “Mangrove Expansion and Contraction at a Poleward Range Limit: Climate Extremes and Land-Ocean Temperature Gradients,” Ecology 98, no. 1 (January 1, 2017): 125–37, https://doi.org/10.1002/ecy.1625.

[19] Ellison and Stoddart, “Mangrove Ecosystem Collapse during Predicted Sea-Level Rise:Holocene Analogues and Implications.”

[20] Snedaker and Araujo, “Stomatal Conductance and Gas Exchange in Four Species of Caribbean Mangroves Exposed to Ambient and Increased CO2.”

[21] Jim Waymer, “Could Mangrove Northern Expansion Temper Global Warming?”

[22] Jennerjahn et al., “Mangrove Ecosystems under Climate Change.”

[23] Doughty et al., “Mangrove Range Expansion Rapidly Increases Coastal Wetland Carbon Storage.”