Sea level rise may imperil species

By Steve Estes

Oncoming sea level rise poses a “serious and growing threat to our nation’s endangered species.”

Such is the conclusion of a recent study on sea-level rise completed by California’s Center for Biological Diversity.

And in that study, the group identifies the endangered Key Deer as one of those, among the top five in fact, most at risk for significant impacts from sea-level rise.

The report says that about 86 percent of the land mass that supports the Key Deer population, which are all in the Lower Florida Keys, is less than three feet above sea level. The deer exist primarily in pine rockland habitat, the last remaining stands of which are located on Big Pine Key, No Name Key and surrounding islands.

The report concludes that sea levels in coastal communities have begun to rise faster than anticipated even 10 years ago and that a three to four foot rise is possible by the end of this century. That will leave the majority of existing habitat for the endangered Key Deer either under water or transitions into salt marsh, neither of which are suitable for deer habitat.

The rising seas will also affect the Key Deer’s fresh water watering holes as salt water creeps into once fresh water lenses and makes the water nearly or completely unsuitable for deer to survive.

The center has urged officials from the US Fish and Wildlife Service, the parent organization for the local National Key Deer Refuge, to start building sea-level rise scenarios into their recovery plans for the deer as a serious threat.

The report suggests that herd managers incorporate the best available science into decision-making processes when determining future recovery plans and fund a comprehensive, science-based analysis of sea level rise threats when making listing determinations for coastal species.

The report also suggests that managers begin looking toward designating comparable critical habitat further from the coast to allow inland migration of threatened species as sea-level rise wipes out former ranges.

The report states that the Key Deer isn’t the only local species that could be at serious risk from the overall effects of sea-level rise.

“The endangered Lower Keys Marsh Rabbit has lost almost half of its habitat because of sea-level rise,” the report states.

Rising sea levels are not a new concern for the local refuge managers.

USFWS personnel announced about five years ago that potential Key Deer habitat nearer the water was already beginning to be affected by rising sea waters. They documented die-offs of pine trees and less salt-tolerant plant life along the outer edges of refuge lands on Cudjoe and Sugarloaf Keys, and the continuing transition of rabbit habitat, tidal marshlands, into salt marshes.

Local scientists report that sea level has risen just over nine inches in the Florida Keys in the last 100 years, and that rise is expected to accelerate as the Earth’s atmosphere reaches the saturation point for carbon absorption.

Herd managers have already attempted to mitigate the survivability of the Key Deer herd by moving animals from the two core population islands of Big Pine and No Name Keys to ranges on Cudjoe and Sugarloaf Keys. Those herds are doing well, say managers, but the forage ranges are suffering the initial impacts of sea level rise and may well be part of history by the end of the century.

The report warns species managers that deep and rapid cuts in greenhouse gas emissions are critical for preventing the worst impacts of sea-level rise. The report also suggests that national efforts be made to decrease large-scale coastal development and instead focus on restoring natural plant and marine communities that mitigate the effects of storm surge, another problem expected to get worse as sea level rises and storm intensities increase.

One of the issues at play in the Keys, however, states the report, is that there is no such thing as inland migration. The higher elevation areas that the species can access already are being accessed. The remainder of the small amount of upland available is nearly gone due to human development.

The local refuge is working with several stakeholder groups now to devise a new Key Deer recovery plan,but no one has as yet said how much of a role future sea-level rise will play in those plans.

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