Publisher :
Place of publication :
Publication year : 2009
Thematic : Conservation
Language : English
Note
For many marine megavertebrate species it is challenging to derive population estimates and knowledge
on habitat use needed to inform conservation planning. For marine turtles, the logistics required to
undertake comprehensive ground-based censuses, across wide spatial and temporal scales, are often
insurmountable. This frequently leads to an approach where a limited number of index nesting beaches
are monitored in great detail by foot. In this study we use nationwide aerial surveying interfaced with
ground assessments across three seasons of leatherback turtle nesting in Gabon (Equatorial West Africa),
highlighting the importance of a synoptic approach to marine turtle monitoring. These surveys allow the
first complete population assessment of this nesting aggregation to be made, identifying it as the world’s
largest for the species (36,185–126,480 clutches, approximating to 5865–20,499 breeding females per
annum and a total estimate of 15,730 to 41,373 breeding females). Our approach also serendipitously
provides insights into the spatial appropriateness of Gabon’s protected areas network, for example
(mean ± 1SD) 79 ± 6% (range 67–86%) of leatherback turtle activities recorded during aerial surveys
(n = 8) occurred within protected areas (345 km, 58%, of surveyed coastline). We identify and discuss
sources of potential error in estimating total nesting effort from aerial surveying techniques and show
that interannual variation in nesting is considerable, which has implications for the detection of statistically
significant changes in population size. Despite its relative costliness per day, aerial surveying can
play an important role in providing estimates of relative population abundance of large vertebrates dispersed
over extensive areas. Furthermore, it can provide data on habitat use and deliver real-time information
on the spatial efficacy of protected area networks.
Go to source
Keywords : life history
Encoded by : Pauline Carmel Joy Eje
