Ecology, Modelling of Habitat Suitability and Conservation Challenges of African Elephant (Loxodonta Africana Blumenbach, 1797) in and Around Omo National Park, Ethiopia
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Date
2024-11
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Addis Ababa University
Abstract
The African savannah elephant (L. africana) is a large endangered herbivorous mammal. Understanding its ecology, habitat suitability, distribution and conservation challenges in and around the Omo National Park (ONP), is key to guide conservation and management initiatives. The survey took place between 2021 and 2022 during both the wet (April–June) and dry (December–February) seasons. Along 32 transects covering a distance of 32 km, elephant dungs were counted using line transect distance sampling technique in the different habitats to estimate elephant population by converting dung density to elephant density. Seasonal habitat suitability and distribution patterns of elephants were assessed using, Species Distribution Models. The seasonal diet composition and feeding behaviour of elephants were assessed using fresh feeding traces collected along their feeding routes. Changes in land use and cover (LULC) between 1993, 2003, 2013 and 2023 in the ONP and surrounding areas were classified and monitored using Landsat satellite imagery, GIS and remote sensing techniques. The estimated number of elephants from the dung count was only 134 (0.22 individuals/km2) for 2021 and 306 (0.44 individuals/km2) for 2022, dry seasons within the extent of elephant habitats in the park. This considerable population difference could be related to habitat requirements and elephant movements in the area. The combined seasonal habitat suitability model using MaxEnt for the currently available potential habitat of L. africana predicted approximately 1999 km2 (39% of the study area), with 365 km2 (7.2%) optimal, 748 km2 (14.7%) suitable and 886 km2 (17.5%) moderately suitable. During the wet and dry seasons, proximity to rivers, canals and LULC had the greatest influence on habitat suitability of L. africana. Elephants consumed 91 plant species grouped into 34 families and 66 genera. During the wet and dry seasons, the largest proportion of their diet came from family Fabaceae (25 and 20%), followed by Meliaceae (10 and 9%) and Poaceae (4 and 18%), respectively. The LULC has changed over the last three decades and these changes in the buffer areas surrounding the ONP have had a greater impact on the status of the elephant population. Within the ONP, the open grassland decreased while other land covers such as savannah wooed grassland, bush land, woodland, forestland and water bodies increased.This could be related to the wildfire, grazing pressure and decline of browsers over the period. Conversely, in the surrounding buffer areas of the ONP, forestland and open grassland decreased, while agriculture land increased significantly. The main factor contributing to the changes in the study area land cover has been agricultural expansion related to local farms and large scale agricultural investments, which have increased by approximately 284% over the past 30 years. Large-scale agriculture and human activities have a significant impact on changes in LULC, which may disturb elephant suitable habitats and migration corridors. These factors were identified as the main causes for the decline of elephant populations in study area. It is therefore recommended to formulate a site and species specific strategy and work with relevant stakeholders at all levels to address the prevailing conservation issues.
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Dung Count, Feeding, Landsat Imagery, Land Use Land Cover, Lower Omo Valley, MaxEnt, Species Distribution Modelling, Classification