Marine debris has been identified as one source of habitat degradation and a threat to coastal and marine species. We conducted a field experiment to understand the effects of large beach debris on sea turtle nesting behavior as well as the effectiveness of large debris removal for habitat restoration. The study beach included three sections (north, middle, and east beaches) along the St. Joseph Peninsula, Florida in the northern Gulf of Mexico. In this study, we separated large debris into two categories: natural and anthropogenic. Natural debris primarily consisted of coarse wooden debris such as downed trees and stumps. Anthropogenic debris included construction materials such as fencing, large pieces of concrete, and cinder blocks. In 2012, we located and measured 643 pieces of large debris (77 pieces in the north, 483 pieces in the middle, and 20 pieces in the east beaches), which covered 2,047.9 m2, or 0.77% of the study beach. The majority (624 of 643) were natural debris, covering 94% of the debris-covered area. We removed large beach debris from the middle section of the study site prior to the start of the sea turtle nesting season in 2013. Then we compared the distribution of nests and false crawls in pre- (2011–2012) and post- (2013–2014) debris removal years in the three sections.
Results/Conclusions
The number of nests increased 200% and the number of false crawls (non-nesting crawls) increased 60% in the experimental section (middle beach), whereas a corresponding increase in the number of nests and false crawls was not observed in the other two sections (north and east beaches) where debris removal was not conducted. The proportion of nest and false crawl abundance in all three beach sections was significantly different between pre- and post-removal years. The substantial increase in sea turtle nesting activities after the removal of large debris indicates large debris may have a serious impact on sea turtle nesting behavior. Removal of large debris could be an effective restoration strategy for improving sea turtle nesting habitat.