Effective sociodemographic population assessment of elusive species in ecology and conservation management

Wildlife managers are urgently searching for improved sociodemographic population assessment methods to evaluate the effectiveness of implemented conservation activities. These need to be inexpensive, appropriate for a wide spectrum of species and straightforward to apply by local staff members with minimal training. Furthermore, conservation management would benefit from single approaches which cover many aspects of population assessment beyond only density estimates, to include for instance social and demographic structure, movement patterns, or species interactions. Remote camera traps have traditionally been used to measure species richness. Currently, there is a rapid move toward using remote camera trapping in density estimation, community ecology, and conservation management. Here, we demonstrate such comprehensive population assessment by linking remote video trapping, spatially explicit capture–recapture (SECR) techniques, and other methods. We apply it to three species: chimpanzees Pan troglodytes troglodytes, gorillas Gorilla gorilla gorilla, and forest elephants Loxodonta cyclotis in Loango National Park, Gabon. All three species exhibited considerable heterogeneity in capture probability at the sex or group level and density was estimated at 1.72, 1.2, and 1.37 individuals per km(2) and male to female sex ratios were 1:2.1, 1:3.2, and 1:2 for chimpanzees, gorillas, and elephants, respectively. Association patterns revealed four, eight, and 18 independent social groups of chimpanzees, gorillas, and elephants, respectively: key information for both conservation management and studies on the species' ecology. Additionally, there was evidence of resident and nonresident elephants within the study area and intersexual variation in home range size among elephants but not chimpanzees. Our study highlights the potential of combining camera trapping and SECR methods in conducting detailed population assessments that go far beyond documenting species diversity patterns or estimating single species population size. Our study design is widely applicable to other species and spatial scales, and moderately trained staff members can collect and process the required data. Furthermore, assessments using the same method can be extended to include several other ecological, behavioral, and demographic aspects: fission and fusion dynamics and intergroup transfers, birth and mortality rates, species interactions, and ranging patterns

Assessing the accuracy of forest cover map for 1990, 2000 and 2010 at national scale in Gabon

The Gabonese Agency for Space Studies and Observations (AGEOS) was set up in 2010 with one of its aims being to develop a national forest monitoring capability. In addition, the European Space Agency (ESA) has developed its activities in the Congo basin through the REDD extension of its GMES Service Element on Forest Monitoring program (GSE\FM). The ESA GSE\FM REDD extension project is seen by the Gabonese authorities as a precursor to the establishment of the AGEOS for the monitoring of forest cover. During this phase of the project, the production of forest area maps and forest cover change maps for 1990 and 2000 was initiated with a wall to wall approach for the total area of Gabon and about a third of the country for 2010. Initial results confirm the generally low level of deforestation expected in the Congo basin region and in Gabon in particular. However, these results cannot be used without a thorough and statistically sound assessment of thematic accuracy. Thus, a suitable sampling approach was developed to assess the accuracy and results show that these products exceed the requirements set by AGEOS with an overall accuracy above 95%