African Journal of Ecology最新文献

The African savannah elephant (Loxodonta africana) is an ecosystem engineer essential in determining the structure and vegetation abundance in mesic dry protected areas such as the Mana Pools National Park (MNP) in Zimbabwe. Understanding the interactions between elephants and vegetation structure is essential for effective conservation and management of savannah ecosystems. Conservation efforts often aim to balance elephant populations with the carrying capacity of their habitats to ensure the sustainability of both flora and fauna within protected areas. Therefore understanding how African savannah elephants influence vegetation structure, abundance and damage is critical for adaptive ecosystem management and wildlife conservation in mesic savannah ecosystems. This study assessed: (i) vegetation structure, (ii) abundance and (iii) evidence of elephant-induced vegetation damage near a distance gradient to water points in MNP. A generalised linear model (GLM) was used to investigate the relationship between vegetation aspects that is structure, abundance and evidence of damage with distance from water sources. In the mesic protected MNP where African savannah elephants predominate, the modelled vegetation shape, abundance and damage exhibit spatial differences on a distant gradient towards water sources (χ², p < 0.05). There is need for implementation of comparably, less costly, homogenous conservation measures for African savannah elephants across the artificial water pans in the MNP.

Vachellia xanthophloea is often observed as a garden ornamental tree in gardens in towns and lodges throughout Namibia. Escapee plants were observed along the Orange River between Komsberg and Sendelingsdrift in southern Namibia and have insidiously invaded the riparian habitat without notice. It is viewed as a native–alien population and may detrimentally affect the local riparian ecology, therefore recommended that eradication be implemented immediately.

Fish provide food and income opportunities for millions of people in Lake Nyasa, also known as Lake Malawi in Malawi and Lake Niassa in Mozambique. Oreochromis karongae (Trewavas, 1941), which is native to Lake Nyasa, Lake Malombe and the Shire River, is at the verge of extinction and has been listed as critically endangered species by the International Union for Conservation of Nature (IUCN), primarily due to overfishing. Using 632 bp of partial mitochondrial cytochrome oxidase subunit I (COI) sequences from 115 samples, this work aims to assess the population genetic status and demographic history of this species to better manage and advance its conservation. The analysis of molecular variance (AMOVA) revealed a low and non-significant genetic differentiation index across the populations under study (ΦST = 0.003, p = 0.278), indicating a lack of population genetic structure. Phylogenetic analysis, grouped together all COI haplotypes of O. karongae from the six sampled sites. Nonetheless, the results showed signs of population expansion from a historic bottleneck, consistent with most data from the Western Indian Ocean Fauna. The findings from this study could be used to improve management and conservation strategies for critically endangered O. karongae in Lake Nyasa.

In addition to the availability of water and invertebrate prey, roost sites are considered the main factors enabling bats to survive in desert areas. Because suitable roost sites are often limiting resources, human constructions are also important for these animals. Conversely, in the context of built heritage conservation, bats are often discussed as a cause of damages. However, if historic structures deteriorate, they may lose their suitability as roosting sites for bats. This study examines how the condition of domed tombs in Sudan affects their use by bats. Inspections of 19 tombs revealed that bats occupied only undamaged structures, with 1652 individuals of four species found. Slightly and partially damaged tombs were not used by bats. These findings highlight the importance of preserving man-made structures as critical roosting sites in arid environments to support local bat populations.

A new fishing technique has been introduced in Lake Kivu, across the Congo side. It consists of gillnets on which light-emitting diode (LED) lamps are attached. Traditional fishermen have introduced the fishing technique without any studies related to the positive and drawback effects of this fishing technique. We sought to understand whether the gillnets with LED lamps fishing technique improve fishing catches and can be regarded as sustainable for the Lake Kivu ecosystem, or is it just only a marketing strategy for gillnets and LED lamp sellers. Two complementary approaches have been used in this study. Experimental fishing campaigns were conducted from June 2021 to June 2022 and monitoring of fishing team in the field coupled with surveys of fishermen about the effectiveness use of this new fishing technique. We observed that (i) 88% of fishermen using gillnet in the Bukavu sub-basin have already adopted the recently introduced fishing technique; (ii) the average catch per unit effort of gillnets with LED lamps is higher than those without LED lamps (3.84 ± 1.95 kg/net vs. 2.69 ± 2.04 kg/net); (iii) these gillnets retrieve larger specimens (79.88 mm vs. 76.69 mm) and generate monthly a higher average profit to fishermen ($916.35) than the fishing technique lacking the LED ($807). However, (iv) the gillnets with LED lamps generates a lot of plastic trash: around 2130 kg of plastic bags/month under fishing conditions in the Bukavu sub-basin. So, this new fishing technique is a real panacea for its practitioners, but a veritable Pandora's box generating plastic pollutants in Lake Kivu. Instead of banning this new fishing technique, we need to adapt it by using submersible LED lamps.

Many species of terrestrial and freshwater chelonians are at risk of extinction, particularly rainforest species due to massive habitat loss. Therefore, the presence of peripheral and isolated populations can have considerable conservation value. This article confirms the presence of Pelusios gabonensis in an area of mature forest in western Côte d'Ivoire for which fragmentary data existed in the literature. It would therefore be important to study the conservation status and the genetics of the Ivorian populations given their huge geographic distance with conspecifics from the Lower Guinean forests.

African savannah elephants (Loxodonta africana) are key ecosystem engineers that migrate over large spatiotemporal scales foraging as they require copious amounts of food and water across habitable landscapes. Therefore a need to understand movement patterns arises in relation to vegetation type and landscape variability, moreso in forage depauparate arid areas such as Gonarezhou National Park (GNP) in Zimbabwe. The objectives of this study were to: (i) assess the performance of vegetation indices in modelling the distribution of African savannah elephants, and (ii) model future landscape variability in Gonarezhou National Park (GNP) in Zimbabwe. Maximum entropy (MaxEnt) algorithm was used to explore the relationship between vegetation indices and distribution of African savannah elephants in the GNP. The Soil Adjusted Vegetation Index (SAVI) performs better relative to other indices in modelling the distribution of African savannah elephants across all habitat types in the GNP. Cellular automata-Artificial Neural Network (CA-ANN) showed a significant future decrease (Kruskal Anova; p < 0.05) in landscape suitable to sustain large populations of African savannah elephants in the GNP by the year 2083. Future remote sensing reveals directional insights into the future consequences of current landscape management for African savannah elephant conservation which is a crucial in the sustainability of climate threatened arid protected areas such as the GNP.

Turtle ecology and conservation have been poorly explored in the West African Sahel regions, and this scarce information has produced a suboptimal management of their populations in the wild. In order to enhance the knowledge on the Sahelian turtle ecology, a field study was carried out in Burkina Faso on the ecology of Pelomedusa subrufa olivacea, a freshwater species inhabiting a wide range of waterbodies throughout West Africa. Reasoned sampling was carried out, resulting in the collection of a total of 196 individuals of Pelomedusa subrufa olivacea. This species shows a relatively balanced distribution of age and sex classes of individuals surveyed in the different study areas. The majority of individuals were observed in specific habitats, confirmed by an aggregative distribution. The potential habitats identified by the MaxEnt model highlight key areas for the conservation of this species in Burkina Faso. Conservation efforts should focus on protecting and restoring temporary and permanent aquatic habitats, and managing human activities to minimize the impact on turtle populations in the West African Sahel.