Abstract
Climate change and human activity threaten sea turtle nesting beaches through increased fooding
and erosion. Understanding the environmental characteristics that enable nesting can aid to preserve
and expand these habitats. While numerous local studies exist, a comprehensive global analysis of
environmental infuences on the distribution of sea turtle nesting habitats remains largely unexplored.
Here, we relate the distribution of global sea turtle nesting to 22 coastal indicators, spanning
hydrodynamic, atmospheric, geophysical, habitat, and human processes. Using state-of-the-art
global datasets and a novel 50-km-resolution hexagonal coastline grid (Coastgons), we employ
machine learning to identify spatially homogeneous patterns in the indicators and correlate these
to the occurrence of nesting grounds. Our fndings suggest sea surface temperature, tidal range,
extreme surges, and proximity to coral and seagrass habitats signifcantly infuence global nesting
distribution. Low tidal ranges and low extreme surges appear to be particularly favorable for individual
species, likely due to reduced nest fooding. Other indicators, previously reported as infuential (e.g.,
precipitation and wind speed), were not as important in our global-scale analysis. Finally, we identify
new, potentially suitable nesting regions for each species. On average, 23% of global coastal regions
between −39◦
and 48◦
latitude could be suitable for nesting, while only 7% is currently used by turtles,
showing that the realized niche is signifcantly smaller than the fundamental niche, and that there
is potential for sea turtles to expand their nesting habitat. Our results help identify suitable nesting
conditions, quantify potential hazards to global nesting habitats, and lay a foundation for naturebased solutions to preserve and potentially expand these habitats.