African Journal of Ecology最新文献

Two multi-species heronries, inland and island, found in the northern part of Nyerere National Park in Tanzania are described. A total of 12 waterbird species were breeding. The inland heronry, located in a bushwillow patch amidst the open savanna habitat, hosted all 12 species. From the drone images taken at the inland heronry, we estimated 3492 individuals for five white bird species (egrets and Africa Sacred Ibis), and 1729 and 160 individuals for the African Openbill and African Spoonbill, respectively. Additionally, we estimated 11 and 55 breeding pairs of spoonbills and ibises, respectively, at the island heronry. Documentation of such large multi-species heronries is limited in Tanzania, especially in the southern region. Therefore, we hope this note will encourage researchers to explore the region for more heronries because these are important sites for waterbirds population management.

Forming mixed-species herds is a common antipredator behaviour of many African herbivores. Here, we quantify the degree to which the common warthog uses herding behaviour as a strategy to potentially reduce risk. We found that warthog occurred in mixed-species herds ~50% of the time and that total herd size of mixed-species herds was significantly larger than single-species herds. We observed that impala—a preferred prey species for several carnivores—were warthog's most common heterospecific herd mate. Finally, within mixed-species herds, warthog orientated themselves so that they were most commonly found to be surrounded by heterospecifics by 180°.

Tropical dry areas are often characterised by a lack of reptile abundance data. For example, in Burkina Faso, the population and ecological distribution of the gecko are poorly understood. Contributing to fill this gap, this study assessed the diversity, density and ecological distribution of geckos in the metropolitan area of Ouagadougou. The study was conducted between 2020 and 2022 using the direct count of individuals in 72 quadrats (each 25 × 25 m²) evenly distributed throughout the entire study area, from a random start. Two distinct species, Hemidactylus angulatus and Ptyodactylus sp. have been encountered. H. angulatus density was estimated as 0.000352 individuals/m² (95% CI: ±0.000336) with a population estimate of 987,360 individuals (95% CI: ±942,480) in 2020; 0.000256 individuals/m² (95% CI: ±0.000432) with a population estimate of 718,080 individuals (95% CI: ±1,211,760) in 2021; and 0.000368 individuals/m² (95% CI: ±0.00048) with a population estimate of 1,032,240 individuals (95% CI: ±1,346,400) in 2022. Ptyodactylus sp. density was estimated as 0.010016 individuals/m² (95% CI: ±0.004608) with a population estimate of 28,094,880 individuals (95% CI: ±12,925,440) in 2020; 0.012352 individuals/m² (95% CI: ±0.005696) with a population estimate of 34,647,360 individuals (95% CI: ±15,977,280) in 2021; and 0.0144 individuals/m² (95% CI: ±0.007136) with a population estimate of 40,392,000 individuals (95% CI: ±20,016,480) in 2022. The spatial distributions of both species were aggregative (dispersion index I = 3.81 for H. angulatus and I = 24.82 for Ptyodactylus sp.). Our study revealed that microhabitat is the resource axis typically partitioned by Ouagadougou geckos. The geckos of Ouagadougou follow the same pattern of available resource partitioning as African reptile communities.

Termite restore plant diversity and soil on altered lands in West Africa with particular abundance of small mound made by Trinervitermes trinervitus, Trinervitermes geminatus, Cubitermes spp. or Microcerotermes spp. The particular abundance of small mounds on altered lands suggests the existence of underlying abiotic and biotic factors. This study investigated the spatial patterns of termite mounds on the altered lands and its relationship with tree distribution in order to sustain the ecological restoration of the altered lands. Thus, unmanned aerial vehicle (UAV) was used to collect images on three different altered land sites of 18 ha characterised with termite mounds. The images were ortho-mosaicked with Pix4D Mapper software. Termite mounds and trees were digitalised on these images in ArcGIS software. The Ripley's pair correlation function using spatstat package was applied to assess the spatial pattern and association of mounds and trees. An aggregative pattern (g(r) > 1) was revealed in the spatial distribution of both termite mounds and trees across all sites. Furthermore, a positive clustered association between termite mounds and trees was noted at two study sites, likely due to the absence of human disturbance. Therefore, this interaction should be vital for assisted ecological restoration and can be factored into efforts to accelerate the restoration of soils and plants on degraded lands. The authors then recommend future research to explore the specific role this attractive relationship plays in ecosystem restoration.

The blue-spotted maskray Neotrygon kuhlii (Müller & Henle, 1841) is a member of the Dasyatidae family of stingrays which grows slowly. Members of this group mature late and have a low fecundity rate. The ICUN Red List of Threatened Species lists N. kuhlii species as data deficient (DD) because information on its ecology and life history is not readily available. The purpose of this study was to determine the genetic diversity, demographic history and population structure of N. kuhlii, all of which are critical information for efforts aimed at conserving the species. The investigation was carried out along Tanzania's coastline using 595 base pairs of partial mitochondrial cytochrome oxidase subunit I (COI) sequence. The haplotype diversity ranged between 0.37 and 0.70 and nucleotide diversity between 0.11% and 0.50%. The findings show that samples from Unguja had higher mean molecular diversity indices than those from other sampling sites. Nonetheless, samples from Mafia and Unguja were found to have the largest effective population size. Genetic variations were found between the subpopulations under study, suggesting limited genetic connectivity among the studied subpopulations. The COI sequences of N. kuhlii from most subpopulations studied showed signs of past population expansion, which are typical for most Western Indian Ocean (WIO) fauna. The findings highlight the need for enhanced management and conservation strategies for N. kuhlii and other coastal stingray species in Tanzania, particularly in areas where sampling sites showed low levels of genetic diversity and effective population size.

Although selective logging has become the primary cause of degradation in many African countries, little is known about its long-term effects. This study investigated the long-term effects of selective logging on forest tree species diversity and dynamics in the East Region of Cameroon. Six permanent monitoring plots of 1 ha each in unlogged and logged forests were established in 2005 and a recensus in 2011. Each 1 ha plot was divided into 25, 20 × 20 m quadrats. Each 20 × 20 m quadrat was further divided into 16, 5 × 5 m subquadrats, where the diameter at breast height (DBH) of all trees ≥ 2 cm was measured. There was a decrease in plant species density and richness in all forest types. Sloetiopsis usambarensis was the most important species in the unlogged forests and forests logged 21 years ago. The most important family was Putrangivaceae, Euphorbiaceae and Violaceae in the unlogged forests and forests logged 11 and 21 years ago, respectively. The frequency distribution of stem size classes indicated a reversed J-shape of tropical forests. The above ground biomass (AGB) recovered more than 50% in all forests, and the unlogged forest had the highest AGB (961.8 Mg/ha). Larger stems indicated a forest at a stage of recovery from disturbance. Silvicultural management should be considered.

Arboreal camera trap photographs were captured of the Central African Oyan Poiana richardsonii in Bwindi Impenetrable National Park, Uganda. In total, 10 photographs were obtained from three sites in the park in 2019. This is likely the furthest east record of this species.

Grivet monkeys (Chlorocebus aethiops aethiops) are opportunistic omnivores and extremely adaptable in both rural and urban environments. A study was conducted out in human-dominated fragmented moist Afromontane forest of wondo genet to investigate the diurnal activity budgets and feeding habits of grivet monkey. Data collection was carried out from February to September 2022 covering both wet and dry seasons. During each scan, individuals were recorded as performing one of the following activities: feeding, moving (searching for food), resting, grooming, playing and others such as drinking, vocalisation and defecation, or aggression and sexual activity. Dietary composition and preferences were assessed using scan sampling method. Proximate analysis was conducted to examine the nutritional makeup of feeding food items. The greatest proportion of the activity time budget of the grivet monkey was devoted to feeding, resting and moving, with relatively higher time devoted to feeding and moving and less time devoted to resting when compared with grivet monkeys inhabiting natural habitats. Grivet monkey utilised 42 food items grouped into 41 plant species and 1 insect. Psidium guava and Desmodium intortum, relatively with higher crude protein and less fibre, were the most preferred plants consumed. The study has pointed out that grivet monkeys in the human-dominated landscape of Wondo Genet remnant moist afromontane forest tend to prefer to consume on fruit tress such as Persea americana, Mangifera indica and Psidium guava, which contain high nutritional content that are planted and managed around homesteads. It is recommended to plant and sustainably manage grivet monkeys' natural foods in human-dominated landscape of Wondo Genet remnant moist afromontane forest to sustainably conserve the species and avoid/reduce human-grivet monkey conflict.