8 research outputs found

    Nationwide abundance and distribution of African forest elephants across Gabon using non-invasive SNP genotyping

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    Robust monitoring programs are essential for understanding changes in wildlife population dynamics and distribution over time, especially for species of conservation concern. In this study, we applied a rapid non-invasive sampling approach to the Critically Endangered African forest elephant (Loxodonta cyclotis), at nationwide scale in its principal remaining population strongholds in Gabon. We used a species-specific customized genetic panel and spatial capture-recapture (SCR) approach, which gave a snapshot of current abundance and density distribution of forest elephants across the country. We estimated mean forest elephant density at 0.38 (95% Confidence Interval 0.24–0.52) per km2 from 18 surveyed sites. We confirm that Gabon is the main forest elephant stronghold, both in terms of estimated population size: 95,110 (95% CI 58,872–131,349) and spatial distribution (250,782 km2). Predicted elephant densities were highest in relatively flat areas with a high proportion of suitable habitat not in proximity to the national border. Protected areas and human pressure were not strong predictors of elephant densities in this study. Our nationwide systematic survey of forest elephants of Gabon serves as a proof-of-concept of application of noninvasive genetic sampling for rigorous population monitoring at large spatial scales. To our knowledge, it is the first nationwide DNA-based assessment of a free-ranging large mammal in Africa. Our findings offer a useful national baseline and status update for forest elephants in Gabon. It will inform adaptive management and stewardship of elephants and forests in the most important national forest elephant stronghold in Africa

    Radiocarbon dating of seized ivory confirms rapid decline in African elephant populations and provides insight into illegal trade.

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    Carbon-14 measurements on 231 elephant ivory specimens from 14 large ivory seizures (≄0.5 ton) made between 2002 and 2014 show that most ivory (ca 90%) was derived from animals that had died less than 3 y before ivory was confiscated. This indicates that the assumption of recent elephant death for mortality estimates of African elephants is correct: Very little "old" ivory is included in large ivory shipments from Africa. We found only one specimen of the 231 analyzed to have a lag time longer than 6 y. Patterns of trade differ by regions: East African ivory, based on genetic assignments of geographic origin, has a much higher fraction of "rapid" transit than ivory originating in the Tridom region of Cameroon-Gabon-Congo. Carbon-14 is an important tool in understanding patterns of movement of illegal wildlife products

    Radiocarbon dating of seized ivory confirms rapid decline in African elephant populations and provides insight into illegal trade

    No full text
    Carbon-14 measurements on 231 elephant ivory specimens from 14 large ivory seizures (≄0.5 ton) made between 2002 and 2014 show that most ivory (ca. 90%) was derived from animals that had died less than 3 y before ivory was confiscated. This indicates that the assumption of recent elephant death for mortality estimates of African elephants is correct: Very little “old” ivory is included in large ivory shipments from Africa. We found only one specimen of the 231 analyzed to have a lag time longer than 6 y. Patterns of trade differ by regions: East African ivory, based on genetic assignments of geographic origin, has a much higher fraction of “rapid” transit than ivory originating in the Tridom region of Cameroon–Gabon–Congo. Carbon-14 is an important tool in understanding patterns of movement of illegal wildlife products

    Updated geographic range maps for giraffe, Giraffa spp., throughout sub‐Saharan Africa, and implications of changing distributions for conservation

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    Giraffe populations have declined in abundance by almost 40% over the last three decades, and the geographic ranges of the species (previously believed to be one, now defined as four species) have been significantly reduced or altered. With substantial changes in land uses, loss of habitat, declining abundance, translocations, and data gaps, the existing geographic range maps for giraffe need to be updated. We performed a review of existing giraffe range data, including aerial and ground observations of giraffe, existing geographic range maps, and available literature. The information we collected was discussed with and validated by subject‐matter experts. Our updates may serve to correct inaccuracies or omissions in the baseline map, or may reflect actual changes in the distribution of giraffe. Relative to the 2016 International Union for Conservation of Nature Red List Assessment range map, the updated geographic range maps show a 5.6% decline in the range area of all giraffe taxa combined. The ranges of Giraffa camelopardalis (northern giraffe) and Giraffa tippelskirchi (Masai giraffe) decreased in area by 37% (122432 km2) and 4.7% (20816 km2) respectively, whereas 14% (41696 km2) of the range of Giraffa reticulata (reticulated giraffe) had not been included in the original geographic range map and has now been added. The range of Giraffa giraffa (southern giraffe) showed little overall change; it increased by 0.1% (419 km2). Ranges were larger than previously reported in six of the 21 range countries (Botswana, Ethiopia, Mozambique, South Sudan, Tanzania, and Zimbabwe), had declined in seven (Cameroon, Central African Republic, Chad, Malawi, Niger, Uganda, and Zambia) and remained unchanged in seven (Angola, Democratic Republic of Congo, eSwatini, Namibia, Rwanda, Somalia, and South Africa). In Kenya, the ranges of both Giraffa tippelskirchi and Giraffa camelopardalis decreased, but the range of Giraffa reticulata was larger than previously believed. Our updated range maps increase existing knowledge, and are important for conservation planning for giraffe. However, since rapid infrastructure development throughout much of Africa is a driver of giraffe population declines, there is an urgent need for a continent‐wide, consistent and systematic giraffe survey to produce more accurate range maps, in order to inform conservation and policy planning
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