Sea turtle nesting patterns in Florida vis‐à‐vis satellite‐derived measures of artificial lighting

Abstract

Light pollution contributes to the degradation and reduction of habitat for wildlife. Nocturnally nesting and hatching sea turtle species are particularly sensitive to artificial light near nesting beaches. At local scales (0.01-0.1 km), artificial light has been experimentally shown to deter nesting females and disorient hatchlings. This study used satellite-based remote sensing to assess broad scale (~1-100s km) effects of artificial light on nesting patterns of loggerhead (Caretta caretta), leatherback (Dermochelys coriacea) and green turtles (Chelonia mydas) along the Florida coastline. Annual artificial nightlight data from 1992 to 2012 acquired by the Defense Meteorological Satellite Program (DMSP) were compared to an extensive nesting dataset for 368,~1 km beach segments from this same 21-year period. Relationships between nest densities and artificial lighting were derived using simultaneous autoregressive models to adjust for the presence of spatial autocorrelation. Though coastal urbanization increased in Florida during this period, nearly two-thirds of the surveyed beaches exhibited decreasing light levels (N = 249); only a small fraction of the beaches showed significant increases (N = 52). Nest densities for all three sea turtle species were negatively influenced by artificial light at neighborhood scales (<100 km); however, only loggerhead and green turtle nest densities were influenced by artificial light levels at the individual beach scale (~1 km). Satellite monitoring shows promise for light management of extensive or remote areas. As the spectral, spatial, and temporal resolutions of the satellite data are coarse, ground measurements are suggested to confirm that artificial light levels on beaches during the nesting season correspond to the annual nightlight measures.

Robotic Vehicles Enable High-Resolution Light Pollution Sampling of Sea Turtle Nesting Beaches

“…Research 7 North Carolina State Parks. Retrieved online at https://www.ncparks.gov on other anthropogenic variables in addition to light that may influence a sea turtle's decision to nest should be incorporated in future studies (Mazor et al, 2013;Weishampel et al, 2016;Kelly et al, 2017) and more nuanced multivariate analyses of nesting characteristics can provide a more holistic understanding of what effects nesting activity. Ongoing coastal development can also result in changes in relationships of nesting data and light.…”

“…These models can accurately extract environmental and topographical features of a shoreline such as beach slope, locations of buildings, vegetation, and escarpments that can influence nest site selection (Kelly et al, 2017). By coupling drone-based high resolution digital elevation models with high resolution light pollution measurements, this method could accurately estimate where topographical features obstruct the path of anthropogenic light, and which individual lights are most problematic, providing the information needed for well-targeted management policies (Weishampel et al, 2016). High resolution light pollution data collected from an autonomous terrestrial rover could also be used to ground-truth future satellite data studies.…”

“…Studies have also utilized satellite-based remote sensing to assess broad scale effects of light pollution on nesting patterns of sea turtles (Kamrowski et al, 2012;Mazor et al, 2013;Brei et al, 2016;Weishampel et al, 2016). Satellite data have been used to compare amounts of light to nesting density on individual nesting beaches; however, satellite pixel size is often much coarser than the width of most nesting beaches and can be subject to cloud cover and moon phase (Kamrowski et al, 2012).…”

“…Satellite data have been used to compare amounts of light to nesting density on individual nesting beaches; however, satellite pixel size is often much coarser than the width of most nesting beaches and can be subject to cloud cover and moon phase (Kamrowski et al, 2012). The resolution of satellite light data can lead to the integration of light sources not directly on the beach or light that could potentially be shaded by vegetation, buildings, or high dunes that nesting sea turtles would not experience (Weishampel et al, 2016). Beachfront lighting in an undeveloped area can also be disregarded in satellite data but could have a significant potential to disrupt local sea turtle nesting (Kamrowski et al, 2012).…”

Leave No Trace ordinances for coastal species management: influences on sea turtle nesting success

“…The availability of optimal habitat for beachdwelling or nesting species such as sea turtles and shorebirds is further reduced by anthropogenic pressures associated with coastal development, including abandoned beach equipment or marine debris, artificial lighting, and human activity (Arianoutsou 1988, Mosier & Witherington 2002, Weishampel et al 2016, Oliver de la Esperanza et al 2017. The introduction of plastics and other debris into the marine environment and its deposition in coastal environments has been increasing rapidly over the past several decades (Hidalgo-Ruz & Thiel 2013, Blickley et al 2016, Löhr et al 2017, Garrison & Fuentes 2019.…”