Vol. XXXVIII, Part 7B 
In: Wagner W., Szekely, B. (eds.): ISPRS TC VII Symposium - 100 Years ISPRS, Vienna, Austria, July 5-7, 2010, IAPRS, Vol. XXXVIII, Part 7B 
ighttime light composites) 
Figure 3. (1) DMSP nighttime lights and superimposed Core 
Florida Index Beach locations; (2) warning sign indicating the 
legal protection status of loggerhead turtle nesting areas (photo, 
www.maxrharris.com/caretta); (3) baby loggerhead properly 
oriented towards the ocean (photo, www.dep.state.fl.us). 
Figure 4. Temporal trends in loggerhead nesting counts and 
anthropogenic beach lighting. 
:ive change since 1992: 
s, (3) gas flares. 
isk’ (Bryant et al., 1998) 
Nations Environment 
nitoring Centre (UNEP- 
en converted into raster 
an. For further spatial 
to a point dataset. In the 
al reef point locations is 
a a region classification 
1 150 distinct geographic 
irchipelago-based). 
>f coral reef exposure to 
lave to be derived from a 
ble data source available 
ighttime lights data, we 
nity Index, LPI), which 
f lights near known coral 
calculated for the three 
(1) human settlements, 
l boats. The contribution 
itance away from the reef 
illation is described in 
ata archive a time series 
oring of temporal trends 
and degradation on a 
poral trend analysis were 
he current version of the 
csites of nighttime lights 
:overing the years 1992 
idicate that since 1992 
jximity to coral reefs has 
n of the expansion in 
il areas in many parts of 
activity (blue graph) has 
improved regulation and 
fishing practices, or the 
tenable to capture using 
m gas flares (red graph) 
lips in 1994 and 2001, a 
ittem from 2002 through 
3.2 Sea turtles 
Turtles are reptiles that are tied to the land for oviposition (egg- 
laying). There are seven species of marine turtles today, six of 
which are listed as endangered and one as threatened. The 
reasons for their listings are diverse, but all are human-caused: 
loss of habitat, habitat alteration, illegal and legal fishing, boat 
hits, pollution, etc. (Nicholas, 2001). One particularly adverse 
effect is light pollution, i.e. the presence of detrimental artificial 
light in the environment. Anthropogenic beach lighting 
significantly impacts critical nocturnal behaviors of marine 
turtles such as (1) the choosing of nesting sites for laying, 
incubating, and hatching eggs, (2) the returning to the sea after 
nesting, and (3) hatchlings finding their way to the sea after 
emerging from their nests (Witherington & Martin, 2000). The 
cues for orienting in the proper direction appear to be based 
upon natural light. Because of their tendency to move in the 
brightest direction, hatchlings show an immediate and well- 
directed orientation towards the water in natural conditions. 
Before anthropogenic lighting, dune silhouettes were typically 
darker than the surf. Now the reverse is often true. On 
artificially lighted beaches, hatchlings become misdirected by 
lighting sources, which leaves them unable to find the water and 
likely to die from dehydration and predation (Salmon, 2003; 
Lome & Salmon, 2007). Furthermore, light pollution literally 
destroys the natural habitat, as beaches become unsuitable for 
nesting. Adult females favor dark beaches for their nest sites 
when emerging from the sea at night, with artificial lighting 
basically deterring them from doing so (Witherington, 1992). 
In the presented study nesting activities of Loggerhead sea 
turtles (Caretta caretta) along the coast of Florida are examined 
and set in relation to the development of artificial night lighting 
as observed by DMSP-OLS (Ziskin et al., 2008). Loggerheads 
live in tropical and temperate oceans and have a generation time 
of approximately 45 years. Mature females (approximately 30 
years old) tend to return to their natal beach to lay their eggs 
(Heppel et al., 1997). Since 1989, the Fish & Wildlife Research 
Institute of the Florida Fish & Wildlife Conservation 
Commission has coordinated the Index Nesting Beach Survey 
(INBS), a detailed sea turtle nesting-trend monitoring program, 
in conjunction with the Statewide Nesting Beach Survey 
(SNBS) program. The INBS program was established with a set 
of standardized data-collection criteria to measure seasonal 
nesting, and to allow accurate comparisons between beaches 
and between years. The INBS program is suited to these trend 
assessments because of its uniformity in beach-survey effort, 
spatial and temporal detail, as well as the specialized annual 
training of beach surveyors. 
To measure the temporal trend in artificial beach lighting 
DMSP-OLS data is used, i.e. the annual mean of persistent 
lights (1992-2007 time series). Imagery was inter-calibrated to 
account for changes in platforms and instrument fluctuations. 
Observations from multiple platforms were averaged. Nighttime 
lights data is superimposed on the locations of Core Florida 
Index Beaches, where surveys of Loggerhead nesting occurred 
(see figure 3). The brightness intensity values are then summed 
up for each index beach pixel. Referring to the natural nocturnal 
marine turtle behavior our hypothesis was that an increase in 
night lights along Florida’s coast would result in a decrease in 
loggerhead sea turtle nesting. Comparing the two time series 
results, we find that Florida has decreased its night lighting near 
nesting beaches, yet total loggerhead sea turtle nesting 
continues to decline (see figure 4). 
The observed 25% decrease in beach lighting since 1996 is 
most likely due to newly introduced legal restrictions. In 1986 
Florida passed a law requiring localities to regulate beachfront 
lighting for the protection of sea turtles (Florida Law 161.163). 
This law was followed by the promulgation of a Model Lighting 
Ordinance in 1993. 
Excerpt from Florida Law 161.163: 
"Coastal areas used by sea turtles; rules. 
—The [Department of Environmental Protection] shall adopt by 
rule a designation of coastal areas which are utilized, or are 
likely to be utilized, by sea turtles for nesting. The department 
shall also adopt by rule guidelines for local government 
regulations that control beachfront lighting to protect 
hatching sea turtles. ” 
Looking at the continuous decline in nesting activities along 
Florida’s coast and taking into account the loggerhead life 
cycle, we come to the following conclusions. Total loggerhead 
nesting has declined for reasons other than contemporary levels 
of anthropogenic beachfront lighting. There would be 
approximately a 30-year lag between hatchling mortality and 
lowered nest counts (female maturity at the age of 30 years). 
With the digital DMSP data archive dating back to 1992, more 
than 10 years of data records would still have to be collected, 
before we might be able to observe direct relations. 
Anthropogenic lighting is furthermore expected to affect nest 
site choice on a scale finer than the entire state of Florida. 
Nesting loggerheads are predicted to favor individual beach 
segments with the lowest levels of anthropogenic lighting. 
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