In comparison, regional and global assessments present a holistic view of population trends and viability, facilitating management decisions at political levels. Understanding trends at individual nesting sites helps enhance conservation initiatives at the local scale, potentially highlighting emerging threats. The flatback turtle ( Natator depressus) remains data-deficient ( 14). Six of the seven sea turtle species are currently listed as vulnerable, endangered, or critically endangered however, the Hawaiian green turtle subpopulation was recently listed as “least concern” in 2012, reflecting a long-term increase in the size of this population ( 9). These trajectories in abundance at nesting sites have been synthesized in species assessments through the International Union for Conservation of Nature (IUCN), which broadly categorizes the conservation status of species ( 14). Over the last 10 years, reports for individual sea turtle nesting sites (rookeries) include both conservation success stories, with long-term increases in the abundance of females and their nest numbers ( 9, 11, 12), and declines, leading to imminent, likely localized extinctions ( 8, 13). Efforts included various beach protection measures, strict fisheries bycatch regulations, and the establishment of marine protected areas ( 7). These declines have motivated worldwide conservation efforts since the 1950s ( 7, 8). Sea turtles are a classic example of a broadly distributed group that has historically suffered population declines, as a result of, for example, bycatch and harvesting adults and eggs ( 6). Our findings highlight the importance of continued conservation and monitoring efforts that underpin this global conservation success story.
#Www seaturtle series#
Furthermore, we also show that, often, time series are too short to identify trends in abundance.
However, conservation concerns remain, such as the decline in leatherback turtles in the Eastern and Western Pacific. Positive trends in abundance are likely linked to the effective protection of eggs and nesting females, as well as reduced bycatch. Adding to this encouraging news for sea turtle conservation, we show that even small sea turtle populations have the capacity to recover, that is, Allee effects appear unimportant. This prevalence of more upward than downward trends was also evident in the individual time series, where we found 95 significant increases in abundance and 35 significant decreases. When levels of abundance were summed within regional management units (RMUs) for each species, there were upward trends in 12 RMUs versus downward trends in 5 RMUs. The time series ranged in length from 6 to 47 years (mean, 16.2 years). To examine the population status of the seven species of sea turtle globally, we obtained 299 time series of annual nesting abundance with a total of 4417 annual estimates. We document a tendency for published estimates of population size in sea turtles to be increasing rather than decreasing across the globe.
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