Browsing by Author "Nauyoma, LineekelaOmwene T"

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    Density and abundance estimation of unmarked ungulates using camera traps in the Mudumu National Park, Namibia
    (European Journal of Wildlife Research, 2024) Nauyoma, LineekelaOmwene T; Warbington, Camille H; Azevedo, Fernanda C; Lemos, Frederico G; Sequeira, Fernando; Fabiano, Ezequiel C
    Density and abundance estimates are critical to effective wildlife management and are essential for monitoring population trends and setting effective quotas for harvesting. Management of roan (Hippotragus equinus) and sable (H. niger) antelopes in Mudumu National Park (MNP), Namibia, is challenging because they are elusive, naturally unmarked, and believed to occur at low densities. The species are threatened by habitat fragmentation, human population growth, and illegal hunting, and reliable density and abundance estimates have not been quantified, hampering management and conservation plans. Our objective was to estimate roan and sable densities and abundances using the time in front of the camera model (TIFC) and the Poisson-binomial N-mixture model (PB), respectively. We also evaluated the effects of environmental and ecological variables on roan and sable abundance. We used data from two camera trap surveys conducted between March and September 2021 in the MNP. Results showed that the TIFC model provided low-density estimates of 1.62 (95% CI 1.61–1.64) roans/km2 and 2.46 (95% CI 2.42–2.50) sables/km2 , consistent with trends reported in Africa where these species occur at low densities. In addition, the total abundance of roans and sables in the MNP from the PB model were 57 and 242, respectively. Higher roan abundance occurred in sites with higher grass cover. This study provides the first accurate camera trap-derived density and abundance estimates for roan and sable in the MNP, which will be critical for developing comprehensive conservation programs and strategies that are likely to reduce the risk of extinction for both species
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    Field surveys and revegetation experiments show that simulation of topographical habitat features could improve the chances of successful restoration for the threatened succulent Juttadinteria albata
    (Society for Ecological Restoration, 2018) Nauyoma, LineekelaOmwene T; Wassenaar, Theo D; Mfune, John KE; Van der Waal, Cornelis; Kwembeya, Ezekeil G
    Species with highly restricted ranges are disproportionately at risk of extinction, particularly where habitat loss occurs as a result of mining. Postmining restoration of rare species populations is considered as an appropriate response to counter such threats, but requires a careful, evidence-based, and information-driven approach. The economically important diamond mining at Sendelingsdrif in the southern Namib Desert occurs in the highly diverse Succulent Karoo Biome and threatens a significant part of the population of the narrow endemic succulent plant species Juttadinteria albata. To decrease the inherent risks of restoring such a rare species, we studied the habitat features of premining J. albata populations and experimentally tested whether some features could assist future reintroductions in postmining substrates. Plots where J. albata occurred were mostly south- to west-facing and had among others higher rock cover and steeper slopes than plots where J. albata plants were absent. A revegetation experiment, with J. albata cuttings that were established on postmining substrate mounds, revealed that plants on steeper slopes, facing south to west, grew faster than plants on other slopes and aspects. Slope and aspect are therefore important habitat properties to recreate when restoring J. albata populations. These, and other preferred habitat properties such as higher levels of organic C, should now be tested in larger-scale field trials. Validation of habitat requirements of J. albata through the revegetation experiment has decreased the risks at least partially and provides additional empirical evidence of the importance of establishing reference conditions to enhance ecological restoration