African Journal of Ecology最新文献

Understanding the spatial and seasonal distribution of African savannah elephants (Loxodonta africana) is critical for conservation and human–elephant conflict (HEC) mitigation in multiuse landscapes. This study assessed African savannah elephant habitat use around Lake Jipe in southern Kenya, across protected and unprotected areas. Using dung density as an index of African savannah elephant presence, systematic quadrant surveys were conducted in three habitat zones during both wet and dry seasons. Environmental variables, including vegetation structure and forage quality, were also evaluated to explore ecological drivers of distribution. Dung densities were consistently higher in protected areas, suggesting a preference for secure habitats. Fewer dung piles were recorded in the dry season than in the wet season, indicating possible seasonal dispersal. African savannah elephant presence declined with increasing distance from the lake, suggesting a strong attraction to lake-associated habitats. Vegetation structure differed across zones; protected areas supported higher grass cover, while unprotected areas showed greater woody species diversity, likely reflecting varied land use. However, no distinct ecological separation was found between zones, indicating localised or anthropogenic factors may influence habitat use. These findings highlight the ecological importance of both land types and suggest that effective management may benefit from spatially adaptive, seasonally informed strategies.

Ants are indicators of habitat disturbance and key providers of ecological services and disservices to agricultural activities. We assessed species richness and functional structure of ant communities in olive groves of the Kabylia region, in northern Algeria. We compared three sampling methods (pitfall traps, hand capture, and bait traps) in four orchards with different elevations. We identified 53 ant species belonging to 17 genera and four subfamilies: Dorylinae, Dolichoderinae, Formicinae, and Myrmicinae. Species richness varied among orchards from 24 to 30, with species accumulation curves suggesting satisfactory coverage at all sites. Hand capture had the highest success per effort, while baits performed the worst. Overall, Kabylia's olive groves were richer in species than many Mediterranean agricultural and even some natural habitats documented in the literature, revealing relatively high ant diversity. Ants were classified into eight functional groups, with an overall composition comparable to similar studies conducted in southern Europe. Hot Climate Specialists, Generalised Myrmicinae, and Opportunists dominated, highlighting the role of thermal stress on the functional composition of the ant communities in the study sites. Many detected species may contribute to key ecological services, including soil enrichment and biological control of weeds and insects.

This study investigates the latitudinal patterns of species richness in tropical forests of Togo, focusing on the roles of species abundance distribution (SAD), total abundance (N) and spatial aggregation (AGG). By analysing biodiversity metrics along a latitudinal gradient, we aim to elucidate the key factors influencing species diversity in this region. Our findings reveal distinct differences between tree and herbaceous species, with tree species exhibiting a positive correlation between richness and total abundance, while herbaceous species show a negative relationship, indicating higher sensitivity to sampling effort. The study highlights the importance of SAD and AGG in shaping biodiversity patterns, with tree species benefiting from a more balanced abundance distribution compared to herbaceous species. Additionally, the research underscores the need for a comprehensive understanding of biodiversity dynamics, considering both ecological and anthropogenic influences. Despite limitations related to geographical scope and sampling methodologies, this study contributes valuable insights into the mechanisms driving biodiversity in tropical ecosystems. The results have significant implications for conservation strategies, emphasising the necessity of preserving diverse habitats to maintain ecological balance and resilience in the face of climate change and human impacts.

Invasive species are known to disrupt native biodiversity, altering plant community composition and ecosystem dynamics. This study examined the influence of Vachellia reficiens, an invasive species, on native plant communities in the Maasai rangelands of Tanzania. Ecological data were collected from 40 paired plots (20 invaded and 20 non-invaded) randomly placed across the landscape, with each plot measuring 50 × 50 m and separated by 50 m to control for environmental conditions. In each plot, all vascular tree species were identified and tree stem counts recorded, with elevation included as an environmental parameter. Species composition and diversity were compared between invaded and non-invaded plots using Shannon-Weiner and Simpson diversity indices. Non-metric multidimensional scaling (NMDS) and Bray–Curtis dissimilarity revealed significant differences in species composition between invaded and non-invaded plots (ANOSIM, R = 0.239, p = 0.001). Indicator species analysis identified several native species, such as V. tortilis (p = 0.001), C. Africana (p = 0.002), V. mellifera (p = 0.004) and S. persica (p = 0.007), as significantly associated with non-invaded plots, indicating their vulnerability to invasion. Diversity indices, species richness (p = 0.011), Shannon-Weiner (p = 0.010) and Simpson (p = 0.015) were significantly lower in invaded areas, suggesting reduced diversity. Although elevation had a lesser influence, it slightly improved model fit. The results suggest that V. reficiens reduces spatial heterogeneity; hence, it homogenises plant communities and lowers native species diversity. Management efforts should prioritise controlling the spread of V. reficiens to protect the biodiversity and ecological health of the rangelands.

Warburgia ugandensis is a valuable medicinal tree native to East Africa, yet its populations are declining due to unsustainable harvesting and habitat degradation. Despite its ecological and socio-economic importance, there is limited information on its current population status and the environmental factors shaping its distribution across different landscapes in northern Tanzania. This study assessed the population density and distribution patterns of W. ugandensis across selected mountainous regions (Mt. Kilimanjaro, Mt. Ketumbeine, Mt. Monduli, Mt. Gelai, and Mt. Longido) in northern Tanzania, and determined how these are affected by land use, elevation gradients, and environmental factors. Data collection involved stratified random sampling across elevation ranges (1000–2500 m a.s.l), encompassing diverse land-use types (national parks, forest reserves, croplands, grazing lands, and settlements). Population density significantly varied among land-use types, with forest reserves showing the highest densities (6.485 ± 1.628 stems/ha), significantly higher than grazing lands (1.833 ± 1.369 stems/ha). Elevation positively correlated with density, where the highest elevations (2001–2500 m a.s.l) supported the greatest density (6.937 ± 1.837 stems/ha). GLM analysis highlighted that elevation, temperature, soil organic carbon, soil pH, and nitrogen significantly influenced W. ugandensis densities. Spatial mapping revealed population hotspots around Mt. Kitumbeine and Mt. Kilimanjaro, highlighting these as priority areas for conservation. Management strategies should prioritise high-elevation forest reserves, considering the critical environmental and soil parameters influencing W. ugandensis distribution.

Scarabids communities (dung beetles) perform critical services in savannah ecosystems including nutrient cycling and soil enrichment but studies that investigate their feeding ecology are still limited. This study aimed to determine the diversity of scarab beetles as well as investigating their associations with vegetation and dung types in Mana Pools National Park, Zimbabwe. Dung traps were used to sample the beetles using three types of dung baits (elephant, buffalo and human) in five vegetation types (mopane, riverine, jesse, miombo and the floodplain) during different times of the day (mornings and afternoons). A total of 52 scarab beetle species were identified during the study period with Kurtops signatus and Neosisyphus calcaratus being the most numerous. The riverine and mopane had the highest scarab beetle abundance and diversity respectively. The elephant dung had the highest beetle numbers but the highest scarab beetle diversity was observed on human faeces. The Euonthophagus vicarius was positively associated with miombo vegetation; Onitis viridulus with riverine vegetation and Sisyphus impressipennis with jesse vegetation. The observed non-random niche overlap suggests that scarab beetle assemblages are structured by deterministic ecological processes rather than stochastic dispersal alone. These results also suggest that dung beetle species preferentially utilise forage resources and that changes in composition of animals in the protected areas may affect their diversity. The projected climatic changes, changes in vegetation and herbivore distribution may also disrupt the services provided by the scarabids.

Despite its small area and the loss of forest cover, Guinea-Bissau still is an environmentally diverse and biodiversity-rich country with a high percentage of protected areas. However, its biodiversity is still poorly known and is under threat from land conversion. Therefore, several rare or declining species may soon disappear before they are studied or even before their former presence or persistence in the country can be confirmed. One of these species was the pygmy hippopotamus (Choeropsis liberiensis), as reported in the journal Mammalia in 1958. With no subsequent data, its former presence in the country was later discredited. Considering that this was not based on an in-depth review of the information and further surveys, we analysed in detail the author identity, the circumstances of the sightings, the existence of other supporting information, and searched for new data through interviews in the rural countryside. We conclude that credit for the past occurrence of the species in the country was justified, but our new data suggest it went extinct, presumably in association with the anticolonial war (1963–1974).