Search

Risk assessment relies on cost–benefit analysis by prey species in relation to predator behavior. The lunar cycle can have strong influences on the way that predator and prey species behave in their environment as light levels can influence activity patterns. By examining how lunar phase influences behavior, we may be able to better predict instances of human–wildlife conflict. As part of the Elephants and Sustainable Agriculture in Kenya project, over 5 years of study have been dedicated to mitigating human–elephant conflict in the Kasigau Wildlife Corridor in southern Kenya, focusing on the construction of deterrent fences and the collection of environmental data in and bordering the Rukinga Wildlife Sanctuary. Elephant presence around crop fields was hypothesized to have a negative relationship with lunar light levels because of an increase in perceived risk from typically greater human activity with moonlight, and a positive relationship with increased darkness during the waning moon phases. The lunar phase data were compared to elephant presence within 12 m of experimental crop fields along the boundary of their wild habitat and human agricultural land to provide insight for potential crop raiding events. Elephants were present significantly less during the full and gibbous moon phases when compared to the new moon phase, and significantly more during the new and waning moon phases. Our findings are being shared with the farmers living in the KWC and may be useful to others living in high HEC areas by providing a form of early warning system that also may have broader applications in the mitigation of other human–wildlife interactions. HIGHLIGHTS Dynamic landscape of fear provides novel insight on elephant behavior near agricultural lands with applications for conservation strategies. [ABSTRACT FROM AUTHOR]

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Land-use change remains the main threat to tropical forests and their dependent fauna and flora, and degradation of existing forest remnants will further accelerate species loss. Forest degradation may result directly from human forest use or through spatial effects of land-use change. Understanding the drivers of forest degradation and its effects on biodiversity is pivotal for formulating impactful forest management and monitoring protocols, but such knowledge is lacking for many biodiversity hotspots, such as the Taita Hills in southeast Kenya. Here we first quantify effects of social factors (human activity and presence) at plot and landscape level, forest management (gazetted vs. non-gazetted) and spatial factors (fragment size and distance to forest edge) on the vegetation structure of indigenous Taita forest fragments. Next, we quantify effects of degraded vegetation structure on arthropod abundance and diversity. We show that human presence and activity at both the plot and landscape level explain variation in vegetation structure. We particularly provide evidence that despite a national ban on cutting of indigenous trees, poaching of pole-sized trees for subsistence use may be simplifying vegetation structure, with the strongest effects in edge-dominated, small forest fragments. Furthermore, we found support for a positive effect of vegetation structure on arthropod abundance, although the effect of daily maximum temperature and yearly variation was more pronounced. Maintenance of multi-layered forest vegetation in addition to reforestation maybe a key to conservation of the endangered and endemic fauna of the Taita Hills. [ABSTRACT FROM AUTHOR]

Unsustainable hunting, both illegal and legal, has led to the extirpation of many species. In the last 35 years giraffe Giraffa spp. populations have declined precipitously, with extinctions documented in seven African countries. Amongst the various reasons for these population declines, poaching is believed to play an important role in some areas. Giraffes are primarily hunted for consumption and for the use of their body parts as trophies and in traditional medicine. However, the socio-economic factors that correlate with the use of giraffe body parts are not well understood. We conducted our study in Tsavo Conservation Area, Kenya, which experiences high levels of poaching. We used semi-structured surveys amongst 331 households to document how giraffe body parts are typically acquired and their intended use (i.e. trophy, medicinal or consumptive). We then used logistic regression models to assess the correlations between nine socio-economic factors and the use of giraffe body parts. We found that giraffe body parts had mostly consumptive and trophy uses. One-time suppliers, opportunistic access and widely known markets were the most common means of acquiring giraffe body parts. Results from our models showed that three variables (gender: men, occupation: tourism worker, and land ownership) were correlated significantly and positively with the use of giraffe body parts. We describe the complex links between socio-economic factors and the use of giraffe body parts and highlight the importance of implementing mitigation measures adapted to local contexts to combat a challenge that many species of conservation concern are facing. [ABSTRACT FROM AUTHOR]

In cooperatively breeding species, group members may derive multiple benefits from helping to raise other individuals' offspring, yet not all individuals do so. In this study, we tested predictions from the "kin selection", "pay-to-stay", "group augmentation" and "skills" hypotheses, to explain why group members feed nestlings of breeding placid greenbuls (Phyllastrephus placidus). In our study population, about 70% of the breeding pairs were accompanied by subordinates, and in 60% of these cases at least one subordinate helped in provisioning nestlings. In total, 80% of the subordinates were related to one or both breeders. In accordance with the "kin selection" hypothesis, and contrary to the "pay-to-stay" hypothesis, all the helpers were first-order kin of the breeding female (although relatedness to the breeding male did not explain variation in helping) and the presence of helpers was associated with increased survival of the breeding pair. However, the propensity to help varied among group members, as 46% of group members related to the breeding female did not feed nestlings. Younger helpers fed offspring more often than older ones, supporting the "skills" and "group augmentation" hypotheses. However, support for the "group augmentation" hypothesis was mixed since subordinate sex and group size did not explain additional variation in helping propensity and effort. We argue that in addition to indirect and direct benefits, also the costs of helping as well as other types of helping aside from provisioning must be considered to better understand variation in helping behavior. [ABSTRACT FROM AUTHOR]

The combined chilli + metal strip and the stand-alone metal strip fence demonstrated significant deterrent effects when compared to the no deterrent control ( I p i = 0.013 & I p i = 0.019, respectively); this also was true at <=6 m (Table 1). We hypothesised that the combined chilli + metal strip fence would be the most effective at deterring elephants because of the double barriers and the multiple modalities stimulated (visual, olfactory, auditory, gustatory), ensuring that elephants retained a negative association with the fence. Chilli + metal strip fence: a combined lower metal strip fence and upper chilli pepper fence. [Extracted from the article]

Socially monogamous females regularly mate with males outside the pair bond. The prevailing explanation for this behavior is that females gain genetic benefits resulting from increased fitness of extra-pair offspring. Furthermore, because of the risk of reduced paternal care in response to cuckoldry, females are expected to seek extra-pair copulations when they can rear offspring with little help from their social partner ("constrained female" hypothesis). We tested these hypotheses and analyzed variation in paternal care in the Afrotropical, facultative cooperative breeding placid greenbul (Phyllastrephus placidus). Overall, approximately 50% of the offspring resulted from extra-pair (and extra-group) mating. Identified extra-pair males were in most cases neighboring dominant males, yet never within-group subordinates. As predicted by the constrained female hypothesis, the occurrence of extra-pair paternity (EPP) increased with the number of cooperative helpers (and not with total group size). However, dominant males did not adjust their food provisioning rates in response to EPP. Although extra-pair males were more strongly related to the dominant female and less heterozygous than the latter's social mate, this did not result in more inbred extra-pair offspring, likely because identified extra-pair males were not representative of the extra-pair male population. While earlier studies on EPP mainly focused on male genetic quality, results from this study provide evidence that female's social context may affect extra-pair strategies too. [ABSTRACT FROM AUTHOR]

Human activities impact upon natural habitats used by birds for breeding and foraging, and lead to changes in the composition and spatial distribution of predator communities, mainly through loss, fragmentation and disturbance of formerly pristine habitat. Yet possible fitness consequences of such changes through impacts on bird nest‐site selection remain poorly known. Here we study nest‐site selection and reproductive success of Placid Greenbuls Phyllastrephus placidus in the Taita Hills, southeast Kenya. We show that habitat features associated with nest‐site selection by this insectivorous, open‐cup‐nesting bird species vary among forest fragments that are exposed to different levels of habitat disturbance. Such differences in sites selected for breeding result from a plastic response to fragment‐specific conditions or may be driven by fragment‐specific variation in the distribution and availability of certain habitat features. Given the overall high nest predation rates in our study area, we expected variation in nest‐site selection to correlate with reproductive success and nestling condition, but detected no such relationship. Because predator density and nest predation rates may vary strongly in space and time, a better understanding of spatio‐temporal variation in predator communities is needed to assess the possible adaptive value of nest‐site selection strategies for reducing the high predation rates that are typical for this and many other open‐cup‐nesting tropical passerines. [ABSTRACT FROM AUTHOR]

Copyright of African Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Since the 1970s, the globally endangered Grevy's zebra Equus grevyi has suffered a substantial reduction in range and population size. Grevy's zebra was introduced into the Tsavo ecosystem in two translocations: 22 individuals released in Tsavo East National Park in 1964 and 30 individuals released in Tsavo West National Park in 1977. This study focuses on the Tsavo East subpopulation within the Kasigau Corridor REDD+ Project Area. Data were collected from 2011 to 2014 using systematic and ad lib methods, while vegetation stratification was based on tonnes of CO2e per hectare. Cumulatively, 785 Grevy's zebra were seen in 210 encounters. The largest single group comprised of 24 individuals; mean group size was 4 ± 3. Foals comprised 10% of all individuals seen and were recorded across most months, suggesting year-round breeding. The range core for the Grevy's zebra in this area was estimated to be 400 km2. Its density was estimated at 0.09 ± 0.038 individuals per km2, translating to a population of 36 ± 15 individuals (range: 6-67) based on the estimated core range. Grasslands and sparse Acacia- Commiphora vegetation strata were used significantly more than expected. Despite constituting only about 2-3% of the global Grevy's zebra population, this subpopulation could still play a role as a - disconnected - reserve population. [ABSTRACT FROM AUTHOR]

For avian group living to be evolutionary stable, multiple fitness benefits are expected. Yet, the difficulty of tracking fledglings, and thus estimating their survival rates, limits our knowledge on how such benefits may manifest postfledging. We radio-tagged breeding females of the Afrotropical cooperatively breeding Placid greenbul ( Phyllastrephus placidus) during nesting. Tracking these females after fledging permitted us to locate juvenile birds, their parents, and any helpers present and to build individual fledgling resighting datasets without incurring mortality costs or causing premature fledging due to handling or transmitter effects. A Bayesian framework was used to infer age-specific mortality rates in relation to group size, fledging date, maternal condition, and nestling condition. Postfledging survival was positively related to group size, with fledglings raised in groups with four helpers showing nearly 30% higher survival until independence compared with pair-only offspring, independent of fledging date, maternal condition or nestling condition. Our results demonstrate the importance of studying the early dependency period just after fledging when assessing presumed benefits of cooperative breeding. While studying small, mobile organisms after they leave the nest remains highly challenging, we argue that the telemetric approach proposed here may be a broadly applicable method to obtain unbiased estimates of postfledging survival. [ABSTRACT FROM AUTHOR]

We examined the effects of vegetation composition and structure on bird species diversity and richness of foraging guilds in the highland agricultural landscape of Nyandarua, Kenya. Bird point counts and vegetation surveys were undertaken during four sampling periods. Linear mixed models were used to examine the effects of vegetation variables on bird species diversity and richness of respective foraging guilds, and logistic generalised linear models used to examine vegetation effects on the presence/absence of the 17 most common bird species. Bird species diversity increased with increasing density of woody plant species and vegetation structural heterogeneity. Two gradients of increasing vegetation structural heterogeneity were most important in influencing bird community composition and had positive effects on species diversity and the presence of most of the species assessed: (1) increasing closed cover due to woody plant density, which also had positive effects on species richness of frugivores and nectarivores, but negative effects on carnivores, and (2) increasing fallow and cultivation versus decreasing grassland/pasture cover, which also had a positive effect on species richness of granivores and omnivores. This study reaffirms the need to maintain a structurally rich agricultural landscape for it to support agrobiodiversity. [ABSTRACT FROM PUBLISHER]

The article focuses on the mechanisms of vulture coexistence and its pattern of abundance in Masai Mara National Reserve, Kenya. It states that the species are associated on the basis of similar dietary needs and morphology of beaks and they rarely show the degree of disassociation. The findings suggests that the changing land use in Mara ecosystem can lead to ungulates reduction which in turn, can adversely affect social vultures.

Habitat fragmentation can restrict geneflow, reduce neighbourhood effective population size, and increase genetic drift and inbreeding in small, isolated habitat remnants. The extent to which habitat fragmentation leads to population fragmentation, however, differs among landscapes and taxa. Commonly, researchers use information on the current status of a species to predict population effects of habitat fragmentation. Such methods, however, do not convey information on species-specific responses to fragmentation. Here, we compare levels of past population differentiation, estimated from microsatellite genotypes, with contemporary dispersal rates, estimated from multi-strata capture-recapture models, to infer changes in mobility over time in seven sympatric, forest-dependent bird species of a Kenyan cloud forest archipelago. Overall, populations of sedentary species were more strongly differentiated and clustered compared to those of vagile ones, while geographical patterning suggested an important role of landscape structure in shaping genetic variation. However, five of seven species with broadly similar levels of genetic differentiation nevertheless differed substantially in their current dispersal rates. We conclude that post-fragmentation levels of vagility, without reference to past population connectivity, may not be the best predictor of how forest fragmentation affects the life history of forest-dependent species. As effective conservation strategies often hinge on accurate prediction of shifts in ecological and genetic relationships among populations, conservation practices based solely upon current population abundances or movements may, in the long term, prove to be inadequate. [ABSTRACT FROM AUTHOR]

The Taita Apalis Apalis fuscigularis (IUCN category: Critically Endangered) is a species endemic to south-eastern Kenya. We assessed population size and habitat use in the three forest sites in which it is known to occur (Ngangao, Chawia and Vuria, totalling 257 ha). The estimate of total population size, derived from distance sampling at 412 sample points, ranged from 310 to 654 individuals, with the northern section of Ngangao fragment having 10-fold higher densities than Chawia (2.47–4.93 versus 0.22–0.41 birds ha−1). Ngangao north alone hosted 50% of the global population of the species. The highly degraded Vuria fragment also had moderately high densities (1.63–3.72 birds ha−1) suggesting that the species tolerates some human disturbance. Taita Apalis prefers vegetation with abundant climbers, but the predictive power of habitat use models was low, suggesting that habitat structure is not a primary cause for the low density of the species in Chawia. Protecting the subpopulation in the northern section of Ngangao is a priority, as is identifying factors responsible of the low abundance in Chawia, because ameliorating conditions in this large fragment could substantially increase the population of Taita Apalis. [ABSTRACT FROM PUBLISHER]

Vulture populations have declined globally as well as regionally within Africa. Little is known about the status of the African White-backed Vulture Gyps africanus in Kenya, but ongoing studies indicate that its population has declined over the last two decades. A total of 32 African White-backed Vulture nests were monitored in the Masai Mara National Reserve over a five-year period between 2003 and 2007. Mean nesting success was 59%, which is comparable to that of populations from southern Africa. Nearest neighbour distances were significantly closer in wooded habitats ('trees and shrubs savanna') than in more open grassland habitats ('open low shrubs'). Based on nearest neighbour distances, the estimated total breeding population within the Masai Mara National Reserve is 1 106 pairs, a figure that may be an overestimate and requires ground-truthing. Collecting baseline data on numbers of breeding pairs and regular nest monitoring are essential in order to assess the impact of various threats to vultures in Kenya, which include growing threats (elephant-mediated habitat disturbance and fire) as well as emerging threats (such as poisoning with the carbamate-based pesticide Furadan™). [ABSTRACT FROM AUTHOR]

Habitat attrition may affect ranging patterns of individuals in natural populations, e.g. by engendering larger territory sizes as the preferred habitat decreases. Radio-telemetry was used to explore the ranging behaviour of the white-starred robin Pogonocichla stellata in the highly fragmented Taita Hills landscape, south-east Kenya. Thirty-one males were radio-tracked in seven indigenous forest fragments differing in size and disturbance level. Although range size did not differ amongst patches, ranges overlapped more in the densely populated fragments. Using principal factor analysis, three principal factors corresponding to ‘openings’ (little foliage cover in all three strata), ‘proper forest’ (three-stratum forest) and ‘forest gaps’ (open upper canopy, dense understorey) were extracted. In all fragments, robins selected sparse to moderate foliage habitats, which best matched to the ‘proper forest’ factor, over open or very dense ones. Yet, the proportion of this preferred vegetation structure within home ranges differed across the forest fragments. Thus, lesser amounts of the selected habitat within the home ranges did not result in larger ranges. This could indicate high robin adaptability, surviving well with only nominal amounts of the preferred habitat within its home range. This is consistent with previous findings on this species based on fluctuating asymmetry and genetics. Résumé L'usure de l'habitat peut affecter les schémas de distribution des individus de populations naturelles, par exemple en générant des territoires de taille plus importante alors que l'habitat préféré diminue. La radio-télémétrie a servi à explorer le comportement de distribution du Rouge-gorge étoilé Pogonocichla stellata dans le paysage très fragmenté des Taita Hills, dans le sud-est du Kenya. On a suivi 31 mâles par radio-tracking dans sept fragments de forêt indigène dont la taille et le niveau de perturbation différaient. Bien que la taille des territoires n'ait pas été différente selon les îlots forestiers, ils se recouvraient davantage dans les îlots plus densément peuplés. En utilisant l'analyse de la composante principale, on a extrait trois facteurs principaux correspondant à des «éclaircies» (peu de couverture foliaire aux trois strates), à«la forêt proprement dite» (forêt à trois strates) et à des «trous dans la forêt» (canopée supérieure ouverte, sous-bois dense). Dans tous les fragments forestiers, les rouges-gorges sélectionnaient les habitats au feuillage rare à modéré, auxquels correspond le mieux la «forêt proprement dite», plutôt que les habitats très ouverts ou très denses. Ceci dit, la proportion de cette structure de végétation préférée au sein des territoires différait selon les fragments forestiers. Donc, une moins grande proportion de cet habitat sélectionné au sein des habitats n'avait pas pour résultat des territoires plus grands. Ceci pourrait indiquer la grande adaptabilité des rouges-gorges qui survivent bien même lorsque la superficie de l'habitat préféré dans leur territoire est minimale. Ceci correspond aux découvertes antérieures concernant cette espèce, basées sur la dissymétrie fluctuante et la génétique. [ABSTRACT FROM AUTHOR]

Sound knowledge of underlying mechanisms is essential for understanding how species respond to habitat fragmentation. Because most threatened species are typically the first ones to suffer local extinctions with forest fragmentation, studying why they fare poorly at the broader landscape scale is difficult. Related, sympatric but common species may be useful surrogates if they can provide insights germane for the conservation of rarer species. We illustrate this using a case study from the highly fragmented Taita Hills forests, south-eastern Kenya, of the Critically Endangered Taita thrush Turdus helleri and the more common white-starred robin Pogonocichla stellata as the surrogate. The responses of the thrush to habitat disturbance were in the same direction as the surrogate robin (e.g. higher fluctuating asymmetry, lower effective population densities and male-biased sex ratios), albeit they were detected sooner and were more severe because of its lower dispersal capacity. The key conservation measures proposed from the surrogate study largely matched those based on an independent evaluation of the thrush data. Additionally, the surrogate provided extra insights into the potential solutions for problems facing the thrush, and provided a base that could be used as a template for restoring the thrush populations in this area. Thus, our findings support the use of surrogate species in the conservation of sympatric related species in fragmented landscapes. We contend that this approach is also applicable for allopatric related species where landscapes are similar, provided that detailed data on population patterns and processes for the surrogate are available. [ABSTRACT FROM AUTHOR]

We examined the effects of habitat fragmentation of the white-starred robin Pogonocichla stellata metapopulation in the Taita Hills archipelago, a hotspot for biodiversity which was fragmented ∼40 years ago. Using seven microsatellite markers, we analysed the robin's genetic structure and tested for equilibrium between migration and drift (testing the probability of decreased dispersal) as well as between mutation and drift (test for recent reduction in effective population size, i.e. bottlenecks). This metapopulation was found to retain relatively high levels of genetic variability (HE between 0.63 and 0.71) and to be in migration-drift equilibrium, suggesting that increased isolation between fragments did not have much effect on the dispersal between them. Furthermore, this equilibrium test greatly enhanced the interpretation of parameters (e.g. FST) assumed to have reached an equilibrium value. In contrast to previous findings on the related and sympatric Taita thrush Turdus helleri (which is critically endangered), there were no indications for recent bottlenecks in any of the robin subpopulations. This difference can be attributed to the higher dispersal capacity of the robin compared with the thrush (deduced from both the genetic and capture-recapture data). Our results stress the importance of sustained dispersal for species conservation. [ABSTRACT FROM AUTHOR]

Three forest and woodland sites were surveyed in the lowlands of the East Usambara mountains, Tanzania, from August to October, 1996. Bombo East I and II Proposed Forest Reserves (PFR) and Bombo West FR were previously unknown biologically. Our fieldwork revealed several records of conservation interest. Four species of global conservation concern (Amani Sunbird Anthreptes pallidigaster, Southern Banded Snake Eagle Circaetus fasciolatus, Fischer's Turaco Tauraco fischeri and Plain-backed Sunbird Anthreptes reichenowi) were recorded, with a further seven species of regional concern. These sites were not as rich in bird species as other East Usambara lowland forests. Bombo East I PFR had the highest richness, which included the presence of three montane species that were most likely cold-season visitors. The Endangered Sokoke Scops Owl Otus ireneae, otherwise known from similar woodland habitat in Kenya as well as lowland forest in the East Usambaras, was apparently absent at these sites. It is also clear from our survey that at least four threatened mammals and one possibly endemic snake inhabit the Brachylaena woodlands and mixed dry forest. Thus, our results indicate that the previously unexplored Brachylaena woodlands and mixed dry forest in north-east Tanzania are an additional habitat to some fauna of threatened status and do, therefore, merit conservation attention. The Brachylaena tree is highly favoured for charcoal production and the enormous demand for this product is increasing the degradation of these woodland patches. Larger tracts of unprotected Brachylaena woodland should receive immediate conservation attention. [ABSTRACT FROM PUBLISHER]

The article discusses the focus of this issue on avifauna, coinciding with the 12th Pan-African Ornithological Congress (PAOC).

The article presents the author's opinion on environmental conservation in Africa. The author states that environment conservation in Africa is often seen as a hindrance to economic prosperity as it resists the poor to improve their livelihoods. He states that conservation there means different thing to different people like defending biodiversity is most important to the environmental activists while Governments and public are not convinced with its merits or they have other priorities.