Managing Moving Targets: Identifying and Responding to Sea Turtle Nesting Range Shifts

By BRIAN K. MEYER, R. KELLY VANCE, and GALE A. BISHOP

Change is nothing new to sea turtles. They have inhabited the Earth for many millions of years, persisting and evolving through the continuous changes in distribution of land and sea, climate, ocean currents, and sea level that have defined their world. First appearing in the fossil record 110 million years ago during the Early Cretaceous, sea turtles have shown remarkable resilience in adapting to environmental changes throughout their history.

The tide washes away the fresh tracks of a nesting leatherback sea turtle © Morrison Mast

The tide washes away the fresh tracks of a nesting leatherback sea turtle © Morrison Mast

Today we are living in a time of accelerated global change. Coastlines, which are dynamic environments to begin with, are being particularly influenced by the extreme weather events and rising seas brought on by climate change. Many sandy beaches are eroding, moving, or disappearing entirely, particularly in the case of low lying atolls and barrier islands. In some areas, sea turtles seem to be moving too. Whether in response to changing habitats, population dynamics, or simply natural patterns in nesting behavior, shifts in sea turtle nesting ranges are being observed. Such shifts bring new challenges for conservationists and resource managers. In cases of habitat loss, we must decide whether and when to intervene. When nesting ranges shift, we are faced with protecting new areas and engaging new stakeholders.

In spite of their adaptability, today’s sea turtles face increasing competition for nesting habitat along the changing coastlines that human interests now dominate. In many cases, their populations have also been decimated by human predation, fisheries bycatch, habitat loss, and other threats that could impede their natural adaptability. Climate change further complicates the situation, as sea level rise against the continents (called transgression by geologists) and warming air and ocean temperatures are expected to influence sea turtles in ways that are largely still unknown. The bottom line is that today’s sea turtle conservationists must learn to identify and respond to change; indeed, it is already happening.

We present here three case studies that document emerging shifts in sea turtle nesting habitat and distribution in Georgia (U.S.A.), Peru, and Hawaii (U.S.A.), and offer them as examples of the challenges faced by conservationists in these times of accelerated change.