Hatchling disorientation after emergence is a major factor impacting sea turtle populations. This study utilized data from over 1,200 Florida Fish and Wildlife Conservation Commission (FWC) Marine Turtle Disorientation Report forms from years 2006 to 2011 to assess changes in the severity and locations of disorientation events and the impact of municipal beach lighting ordinances. While the FWC forms were completed for all sea turtle species observed, this study focused only on loggerhead sea turtles (Caretta caretta). A Disorientation Severity Index (DSI) was derived from the number of hatchlings and the direction of their tracks leaving the nests to evaluate the changes in disorientation over six years in Broward County. The FWC forms provide a much larger database for the analysis of hatchling disorientation patterns and trends than can be derived from the more precise, but labor intensive, Hatchling Orientation Index (HOI) survey method of Witherington et al. (1996). This research differs from prior work by focusing on the information provided in the FWC Marine Turtle Disorientation Report forms; using each individual disorientation to assess changes in the severity of hatchling disorientations over time. Prior work has not used the FWC forms for analysis. Significant differences were found for average DSI between years and locations. Overall, DSI decreased significantly from 2006 to 2011 in Hillsboro Beach, Pompano Beach, Lauderdale-by-the-Sea, Fort Lauderdale, and Hollywood. This might be due to increased compliance with lighting ordinances. In addition, disorientation hotspots were identified and the DSI in these hotspots decreased significantly in central and south Fort Lauderdale, Pompano Beach, and Lauderdale-by-the-Sea. Hotspots were visually identified as R-Zone ranges with higher numbers of disorientations than in other ranges (Fig. 6). Artificial beach illumination is very prevalent in Broward County. However, there was no significant relationship between the number of types of lights that were recorded on the FWC forms and DSI. Disorientations seemed to be clustered within hotspots with known lighting issues. Management strategies should use these analyses to reassess loggerhead recovery plans to reduce disorientation hotspots and increase hatchling recruitment.

Sammanfattning Nattfjärilar är en utsatt grupp när det kommer till nattbelysning, eftersom nattbelysning påverkar processer som födosök och reproduktion samt ökar deras mortalitet genom stress och ökad risk för predation. Mörka och belysta lokaler i Halmstads urbana grönområden undersöktes för att studera nattbelysningens påverkan på nattfjärilars individantal och artdiversitet. I studien visade vi på signifikanta skillnader hos både nattfjärilars individantal samt artdiversitet mellan de mörka och belysta lokalerna, där tillhörande analyser visade signifikant färre antal individer och likaså negativ trend för artdiversiteten. Analyserna visade att minskad artdiversitet och individantal i belysta lokaler inte var signifikant korrelerat med belysningsstyrkan i lokalerna. Dock finns det indikationer på att belysningsstyrkan eventuellt haft en negativ påverkan på individantalet och artdiversiteten av nattfjärilar i denna studie. Det fanns en belyst lokal som utmärkte sig med ovanligt hög diversitet där artdiversiteten var det tredje högsta uppmätta värdet i hela studien. Detta kan eventuellt bero på förekomsten av blommande buskage vilket återfanns i direkt anslutning till inventeringsområdet. Vi föreslår därför att blommande växter och buskage kan implementeras som åtgärd för att förebygga nattbelysningens påverkan på nattfjärilspopulationer. Kompletterande samt uppföljande studier av ämnet kring vilka växter som passar specifikt för nattfjärilar behövs, då det i dagsläget är ett ämne som i Sverige behöver utvecklas innan implementering av passande växter kan bli en lämplig åtgärd. / Abstract Moths are a vulnerable group when exposed to night lighting, it affects their basic drives such as foraging and reproduction and increases their mortality through stress and increased risk of predation. Dark and illuminated localities in Halmstads’ urban green areas were inventoried to study the impact of night illumination on the number of individuals and species diversity of moths. In the study, significant differences were found in the individual number of moths and species diversity between the dark and illuminated localities, which could not be significantly correlated to illuminance present in the localities. However, there were indications that illuminance may still have negatively affected the number of individuals and species diversity of moths in this study. There was one illuminated locality that stood out from the rest where species diversity was the third highest measurement from the entire study, which can possibly be attributed to the presence of flowering shrubs. Therefore we suggest that flowering shrubbery can be implemented as a measure to prevent the impact of night illumination on moth populations and becomes the basis for supplementary and follow-up studies of the subject.