African Journal of Ecology最新文献

Livingstone's fruit bat (Pteropus livingstonii) is among the most threatened bats worldwide. As the species is an important pollinator and seed disperser of Comoros plants with a crucial role in forest regeneration, it is critical to understand how human-induced habitat disturbance impacts genetic structure at fine spatial scales in order to define conservation strategies. In this study, we assessed the level of genetic structure between eight colonies of the species and found that this was strong genetic structures between roosts that can be explained by isolation due both to distance and habitat fragmentation. Mitigation measures should aim to restore population connectivity.

Stingless bees are important pollinators and producers of honey used in folk medicine. We investigate the nectar sources for two Afrotropical stingless bee species, Hypotrigona araujoi and Meliponula ferruginea. Pollen was extracted and processed using next-generation sequencing (NGS) methods, DNA metabarcoding. Results show that stingless bees visited 32 plant genera. Wild plants were the major nectar sources for the two stingless bees' species. The diversity of plants visited and honey physical–chemical characteristics differed between the two bee species, suggesting that they use comparable spectra of host plants. This information should help prioritise the conservation of identified forage plants.

In the past 24 years, the Southwestern Indian Ocean (SWIO) region has lost about 4% of its mangroves due to unsustainable extraction, land clearance for agriculture and climate change impacts. Since this loss risks fragmenting mangrove fauna, this study analysed 179 D-loop sequences (329 base pairs) of Barred mudskipper (Periophthalmus argentilineatus) sampled from estuarine mangroves in the SWIO to test two hypotheses: (1) whether Barred mudskipper populations in the region display genetic connectivity along the fragmented mangroves and (2) whether these populations have experienced demographic declines in recent history. The populations showed low and insignificant indices of genetic differentiation (F_ST = −0.00068, p > 0.05; Φ_ST = 0.005, p > 0.05), and haplotypes from different localities did not cluster according to their geographical origins. Similarly, Bayesian phylogenetic analysis grouped all SWIO haplotypes into one cluster, suggesting the hypothesis of genetic interconnectedness could not be rejected. Furthermore, the populations showed high haplotype diversity (0.96 ± 0.007) combined with low nucleotide diversity (1.09 ± 0.61%). They also showed significant negative Tajima's D values (−1.71, p < 0.02) and a unimodal mismatch distribution, indicating the hypothesis of demographic expansion post a historical bottleneck could not be rejected. Nevertheless, the Bayesian skyline plot indicated an increase in population size post-bottleneck, suggesting an ongoing recovery. These findings indicate that, despite varying management approaches in the SWIO, Barred mudskipper populations exhibit genetic exchange that transcends geographical and administrative borders. This implies that their populations should be considered a single stock within the region. These findings underscore the need for coordinated management approaches among the SWIO countries. This is crucial because inconsistencies in conservation measures across borders could disrupt the population's interconnectedness, potentially impacting their genetic integrity and long-term survival.

Lions (Panthera leo) are a keystone species of many wildlife areas and, as such, understanding their dietary ecology is important for holistic wildlife management. Knowledge of lion feeding ecology enables researchers and wildlife managers to better understand predator–prey dynamics and ecological limits governing their local contexts. Where kill sites can be physically located in the field, they can provide important baseline information on lion diet. In this study, Global Positioning System (GPS) collar data were used together with field observations to investigate the dietary breadth of lions at Malilangwe Wildlife Reserve, Zimbabwe. Results showed that lions in our study had a moderately specialised diet with zebra (Equus quagga) constituting the largest proportion of prey species consumed. A massive anthrax outbreak occurred during the study, drastically reducing numbers of several prey species, and this provided an opportunity to test possible shifts in lion diet in response to changes in prey abundance. Prey species selection before the anthrax outbreak was significantly different to the period after the outbreak, indicating a shift in diet post-outbreak. Notable increases were observed in kill rates of species that were not severely affected by anthrax, namely warthog (Phacochoerus africanus), zebra, wildebeest (Connochaetes taurinus) and eland (Taurotragus oryx). Quantifying lion dietary requirements is important for assessing the ecological and economic impacts they have on prey populations. In addition to space-use ecology, this study shows that GPS collar data can facilitate diet investigation in large carnivores thereby providing useful information for ecological management.

The diurnal activity budgets of giraffes were effectively studied from June 2012 until August 2013, in the Kalahari Region of southern Africa. Direct field observations identified how the daily activity budgets varied amongst the different subgroups of giraffes and the effects of seasonal changes and the time of the day. Feeding was the highest-performed activity whilst non-feeding activities were, however, also prominent. This study aimed to determine why giraffes are willing to sacrifice time on non-feeding activities. A deeper look into the social and non-feeding-related behaviour of giraffes might prove that giraffes devote significant time to various other activities to improve their health and comfort. It unveils trade-offs between digestion efficiency and foraging, impacting energy gain. Understanding this balance informs conservation strategies, habitat management and their well-being. Investigating the motivations behind these behavioural choices unveils adaptive mechanisms, shedding light on the intricate interplay between physiological and ecological needs, ultimately contributing to a holistic comprehension of giraffe's ecological roles and promoting their coexistence with their environment. Such investigations also aid in highlighting why giraffes' social structures should be considered as complex and why further research is needed to better understand these relationships, amongst subspecies.

The Critically Endangered Nubian Flapshell Turtle (Cyclanorbis elegans) is found in the White Nile River system in South Sudan and northern Uganda. Over the past few decades, its populations have sharply declined, primarily due to human-induced threats, leading to its near-extinction across almost its entire range. In this paper, we present the results of a comprehensive threat analysis undertaken to pinpoint the challenges confronting the species within its natural habitat, specifically in the only known sites where it currently exists. We aimed to develop a conceptual framework to understand causal relationships among driving forces, threats and the target species. This framework allows the visualisation and analysis of the web of intricate interactions that contribute to the species' decline and vulnerability. We convened a panel of experts who identified three primary direct threats to the Nubian Flapshell Turtle: (1) Sand mining (IUCN code 3.2); (2) Overfishing by native fishers and refugees (code 5.4) and (3) Habitat loss at nesting sites (code 7.3). Among these threats, overfishing had the largest geographical extension, the highest intensity and duration, while habitat loss occurred at the highest frequency. These threats varied significantly in intensity and frequency. Additionally, when assessing the overall magnitude of these threats, habitat loss and overfishing had the highest impact, with significantly higher scores compared to sand mining. Our experts also identified the underlying driving forces behind these threats: (1) Economic interests driving sand mining activities along the Nile; (2) The influence of civil conflict and refugee populations, which contribute to the demand for bushmeat; (3) the Chinese expatriates, that lead to overfishing; (4) The removal of bank vegetation serves as a catalyst for habitat loss at nesting sites. The resulting conceptual framework serves as a valuable tool for defining targeted conservation measures for each distinct threat.

A better understanding of the natural regeneration in tropical forests could help develop more effective restoration strategies. This study examined relationships in structural and diversity attributes of natural regeneration in five forest fallow ages after slash-and-burn agriculture (6 months, 2 years, 5 years, 10 years, and 15 years) in the Republic of Congo. For each fallow age, all stems with a diameter ≥1 cm and below 5 cm (height ≥ 130 cm), corresponding to natural forest regeneration, were identified to the species level, and measured (diameter and height) in 12 plots (10 m × 10 m). Three structural attributes (stem density, maximum diameter, and maximum height) and five diversity indices (species richness, Shannon diversity, Simpson diversity, Fisher's alpha and Pielou's evenness) were estimated at the plot level. Our results revealed an increase in structural and diversity attributes with fallow ages, except stem density. The young fallow (6 months, 2 years and 5 years) had greater stem density (61 ± 48 stems), while the old fallow (10 years and 15 years) had higher maximum height (5.39 ± 2.36 m) and Shannon's index (0.94 ± 0.18). These results provided new insights into natural regeneration between young and old secondary forests.

Though there is consent that poaching is an important driver of wildlife declines in many African forests, we lack a deeper understanding of the factors behind population patterns in Afrotropical landscapes to inform conservation management. We surveyed line transects in four Cameroonian sites of different protection status in 2013/2014, namely Korup National Park, Banyang Mbo Wildlife Reserve, one timber concession and a section of an unprotected agroforestry matrix, and used data from 2007 for trend assessment. We used GLMs to identify predictors for mammal distribution based on a set of variables. While species compositions showed complex trend patterns, it is noteworthy that chimpanzee and elephant abundances declined significantly in the Banyang Mbo Wildlife Reserve. Although landscape management type affected the distribution of most mammal species, anthropogenic or environmental variables were strong predictors. Chimpanzee, elephant and drill abundances were higher at a larger distance to settlements. Vegetation density positively affected a number of species, including chimpanzee and red colobus. Several species were more abundant in rough terrain, probably because of reduced poaching. Our results suggest that protected areas in Southwest Cameroon had a mitigating effect on wildlife declines, mainly due to their remoteness and habitat quality, rather than management interventions.

Variations in physico-chemical parameters of water as abiotic factors affect the spatio-temporal distributions of the organisms that live in it. The present study aims to determine the influence of physico-chemical properties on Ardeidae spatio-temporal variations in the wetland of Ramsar site 1018 in Benin. To reach this goal, transect enumeration techniques and stationary counts lasting 15–30 min were used to count Ardeidae species once a month at different sites such as Nokoué Lake, Sô River, Porto-Novo Lagoon, Ouémé River and ancient Lagoons from January 2015 to December 2016. Water physico-chemical parameters were measured at three stations per site during the bird counts. Five of the 12 species recorded monthly were significantly influenced (p < 0.05) by water physico-chemical parameters. It was then revealed that pH influenced Ardeidae spatial variation. Such information is relevant to the management of Ramsar Site 1018, which hosts migratory waterbird species from Palearctic (Eurasia) every year.

Vervet monkeys (Chlorocebus pygerythrus) are a widespread, typically seasonally breeding African primate. We report pregnancy complications in wild females in the urban mosaic landscape of Durban, South Africa, that required admittance to a wildlife rehabilitation centre. We found pregnancy complications in 13 female vervet monkey adults and subadults, with most cases (69.2%) in spring. Dystocia (difficult or obstructed labour) was the main cause of admission (46.2%), and in 69.2% of cases, a veterinarian attended to the animal. However, most pregnancy complications resulted in death (86.6%). Concerns about increased anthropogenic food causing increased birth size need further investigation.