Browsing by Author "Meier, Amelia"
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Item Open Access Forest elephant movement and habitat use in a tropical forest-grassland mosaic in Gabon.(PloS one, 2018-01) Mills, Emily C; Poulsen, John R; Fay, J Michael; Morkel, Peter; Clark, Connie J; Meier, Amelia; Beirne, Christopher; White, Lee JTPoaching of forest elephants (Loxodonta cyclotis) for ivory has decimated their populations in Central Africa. Studying elephant movement can provide insight into habitat and resource use to reveal where, when, and why they move and guide conservation efforts. We fitted 17 forest elephants with global positioning system (GPS) collars in 2015 and 2016 in the tropical forest-grassland mosaic of the Wonga Wongué Presidential Reserve (WW), Gabon. Using the location data, we quantified movement distances, home ranges, and habitat use to examine the environmental drivers of elephant movements and predict where elephants occur spatially and temporally. Forest elephants, on average, traveled 2,840 km annually and had home ranges of 713 km2, with males covering significantly larger home ranges than females. Forest elephants demonstrated both daily and seasonal movement patterns. Daily, they moved between forest and grassland at dawn and dusk. Seasonally, they spent proportionally more time in grassland than forest during the short-wet season when grasses recruit. Forest elephants also traveled faster during the short-wet season when fruit availability was greatest, likely reflecting long, direct movements to preferred fruiting tree species. Forest elephants tended to select areas with high tree and shrub density that afford cover and browse. When villages occurred in their home ranges elephants spent a disproportionate amount of time near them, particularly in the dry season, probably for access to agricultural crops and preferred habitat. Given the importance of the grassland habitat for elephants, maintenance of the forest-grassland matrix is a conservation priority in WW. Law enforcement, outreach, and education should focus on areas of potential human-elephant conflict near villages along the borders of the reserve. GPS-tracking should be extended into multi-use areas in the peripheries of protected areas to evaluate the effects of human disturbance on elephant movements and to maintain connectivity among elephant populations in Gabon.Item Open Access Poaching empties critical Central African wilderness of forest elephants.(Curr Biol, 2017-02-20) Poulsen, John R; Koerner, Sally E; Moore, Sarah; Medjibe, Vincent P; Blake, Stephen; Clark, Connie J; Akou, Mark Ella; Fay, Michael; Meier, Amelia; Okouyi, Joseph; Rosin, Cooper; White, Lee JTElephant populations are in peril everywhere, but forest elephants in Central Africa have sustained alarming losses in the last decade [1]. Large, remote protected areas are thought to best safeguard forest elephants by supporting large populations buffered from habitat fragmentation, edge effects and human pressures. One such area, the Minkébé National Park (MNP), Gabon, was created chiefly for its reputation of harboring a large elephant population. MNP held the highest densities of elephants in Central Africa at the turn of the century, and was considered a critical sanctuary for forest elephants because of its relatively large size and isolation. We assessed population change in the park and its surroundings between 2004 and 2014. Using two independent modeling approaches, we estimated a 78-81% decline in elephant numbers over ten years - a loss of more than 25,000 elephants. While poaching occurs from within Gabon, cross-border poaching largely drove the precipitous drop in elephant numbers. With nearly 50% of forest elephants in Central Africa thought to reside in Gabon [1], their loss from the park is a considerable setback for the preservation of the species.Item Open Access The ecological consequences of forest elephant declines for Afrotropical forests.(Conservation biology : the journal of the Society for Conservation Biology, 2017-10-27) Poulsen, John R; Rosin, Cooper; Meier, Amelia; Mills, Emily; Nuñez, Chase L; Koerner, Sally E; Blanchard, Emily; Callejas, Jennifer; Moore, Sarah; Sowers, MarkPoaching is rapidly extirpating African forest elephants (Loxodonta cyclotis) from most of their historical range, leaving vast areas of elephant-free tropical forest. Elephants are ecological engineers that create and maintain forest habitat, thus their loss will have strong consequences for the composition and structure of Afrotropical forests. We evaluated the roles of forest elephants in seed dispersal, nutrient recycling, and herbivory and physical damage to predict the cascading ecological effects of their population declines. Loss of seed dispersal by elephants will favor tree species dispersed abiotically and by smaller dispersal agents, with tree species composition depending on the downstream effects of changes in elephant nutrient cycling and browsing. Loss of trampling and herbivory of seedlings and saplings will result in high tree density as they are released from the pressures of browsing. Diminished seed dispersal by elephants and high stem density are likely to reduce the recruitment of large trees, resulting in a more homogeneous forest structure and decreased carbon stocks. In sum, the loss of ecological services by forest elephants will likely transform Central African forests to be more like Neotropical forests, from which megafauna were extirpated thousands of years ago. Without intervention, as much as 96% of Central African forests will have modified species composition and structure as elephants are compressed into remaining protected areas. Stopping elephant poaching is an urgent first step to mitigating these effects, but long-term conservation will require land use planning that incorporates elephant habitat into forested landscapes that are being rapidly transformed by industrial agriculture and logging. This article is protected by copyright. All rights reserved.