Case study data 2022: The effects of dune plant roots on loggerhead turtle (Caretta caretta) nest success

Sand dunes are supported by the extensive root systems of dune plants that
anchor the dune and protect it from erosion. While all plants that grow on
the dunes support their structure, invasive plants can outcompete native
and non-native dune plants for resources such as nutrients, sunlight, and
space to grow. During the summer, sea turtles lay nests on beaches and
near dunes; however, their eggs and hatchlings are at risk of destruction
and entrapment by dune plant root penetration. Dune plant roots can
penetrate sea turtle nest cavities, thus decreasing the hatching success
of the eggs and the emergence success of the hatchlings. The purpose of
this project was to determine how plant roots impact loggerhead sea turtle
(Caretta caretta) nest success on Casey Key, Sarasota County, Florida,
USA, and to assess which factors affect plant root invasion. We predicted
(1) a negative impact on loggerhead sea turtle nests by plant roots, (2)
invasive plants have a larger impact than native or non-native plants, and
(3) the distance from the dune affects whether roots will penetrate the
nest. Data from nests excavated in 2022 were used to determine the extent
of root penetration and species of plants were documented. Statistical
models were used to identify which variables had the greatest effect on
root penetration. The results of this study conclude that root presence in
the nest cavity decreases both hatch and emergence success of hatchlings
within the nest and that nests closer to the dune are more likely to have
a higher proportion of root damage and lower hatch and emergence success.
This study helps advance understanding of how and if invasive plants
affect sea turtle reproductive success and helps inform coastal management
aimed at conserving threatened loggerhead populations.