Coastal Forests Of Kenya Research Articles

Description of four Iolaus Hbner, 1819 species in the subgenus Philiolaus Stempffer amp; Bennett, 1958 from East Africa, assigned to the proposed I. maritimus species group (Lepidoptera, Lycaenidae, Theclinae).

Four new Iolaus Hbner, 1819 species are described in the subgenus Philiolaus Stempffer Bennett, 1958. They are assigned to the newly formed I. maritimus species group. Members of the group occur in the coastal forests of Kenya, submontane and montane forests in Tanzania and Mozambique, and are locally distributed in montane forests at the western shores of Lake Malawi, in southwestern Tanzania, and northern Zambia/Malawi.

Three new species of Uvariodendron (Annonaceae) from coastal East Africa in Kenya and Tanzania.

East Africa is a hotspot of biodiversity with many endemic plant species. We describe three new species of the genus Uvariodendron (Annonaceae) from the coastal forests of Kenya and Tanzania. Uvariodendron mbagoi Dagallier & Couvreur, sp. nov. is endemic to Tanzania and unique within the genus by its strong bergamot scent and its tomentose fruits having regular tufts of higher hair density. Uvariodendron dzomboense Dagallier, W.R.Q. Luke & Couvreur, sp. nov. is endemic to Dzombo Hill in Kenya and is rendered distinct by its small leaves and very densely pubescent carpels. Uvariodendron schmidtii W.R.Q. Luke, Dagallier & Couvreur, sp. nov. is endemic to Shimba Hills in Kenya and differs by its small flowers and fused sepals forming a ring. Following IUCN criteria we assessed U. mbagoi and U. dzomboense as endangered (EN) while U. schmidtii is assessed as Vulnerable (VU). We also propose a new combination: Polyceratocarpus oligocarpus (Verdc.) Dagallier, comb. nov. The description of these three new species underlines the richness in endemics in East Africa and that new discoveries might arise from further botanical exploration of this region.

Woody plant species diversity of the coastal forests of Kenya: filling in knowledge gaps in a biodiversity hotspot

The coastal forests of Kenya are global biodiversity hotspots known for rich plant diversity and endemism. They exist as fragmented forest islands, and their current conservation status and quantitative trends in plant diversity are understudied. We investigated these knowledge gaps by providing a comprehensive literature review and comparing to field data collected using standardized sampling protocol. Our goals were to build a robust basis for future analyses, biodiversity monitoring, and to understand the role of fragment area in determining species richness. We recorded a total of 937 woody species belonging to 88 families in 30 forest patches from reviewed and sampled data. Species richness per site from literature review was affected by biases in data scarcity, forest size and variation in sampling methods. In general, large forests reserves of Shimba hills and Arabuko exhibited a high number of cumulative species compared to smaller forest patches. Species-area relationship showed a significant proportion of species richness per forest was determined by forest area, according to Arrhenius model. This study is the first to review forest patch woody plant species diversity knowledge gaps in the coastal forests of Kenya, and the resulting comparison provides the first quantitative overview and foundation of these forests.

A new Vegetation-Plot Database for the Coastal Forests of Kenya

Biodiversity data based on standardised sampling designs are key to ecosystem conservation. Data of this sort have been lacking for the Kenyan coastal forests despite being biodiversity hotspots. Here, we introduce the Kenyan Coastal Forests Vegetation-Plot Database (GIVD ID: AF-KE-001), consisting of data from 158 plots, subdivided into 3,160 subplots, across 25 forests. All plots include data on tree identity, diameter and height. Abundance of shrubs is presented for 316 subplots. We recorded 600 taxa belonging to 80 families, 549 of which identified to species and 51 to genus level. Species richness per forest site varied between 43 and 195 species; mean diameter between 13.0 ± 9.8 and 30.7 ± 20.7 cm; and mean tree height between 5.49 ± 3.99 and 12.29 ± 10.61 m. This is the first plot-level database of plant communities across Kenyan coastal forests. It will be highly valuable for analysing biodiversity patterns and assessing future changes in this ecosystem. Taxonomic reference: African Plant Database (African Plant Database version 3.4.0). Abbreviations: DBH = diameter at breast height; GIVD = Global Index of Vegetation-Plot Databases; KECF-VPD = Kenyan Coastal Forests Vegetation Plot Database.

<p><strong><em>Zehneria monocarpa</em></strong><strong> (Cucurbitaceae), a new species from the relicts of Kenya’s coastal forests</strong></p>

Zehneria monocarpa (Cucurbitaceae), a new species from the fragmented lowland coastal forests of Kenya is described here and illustrated with photographs. It resembles Z. oligosperma and Z. longiflora, but can be distinguished by its solitary female flowers and fruits. Furthermore, the new species has 1–23 conspicuous dark green glands on the apex of the leaf and the inner part of its receptacle tube is entirely hairy.

An annotated checklist of the coastal forests of Kenya, East Africa.

The inadequacy of information impedes society’s competence to find out the cause or degree of a problem or even to avoid further losses in an ecosystem. It becomes even harder to identify all the biological resources at risk because there is no exhaustive inventory of either fauna or flora of a particular region. Coastal forests of Kenya are located in the southeast part of Kenya and are distributed mainly in four counties: Kwale, Kilifi, Lamu, and Tana River County. They are a stretch of fragmented forests ca. 30−120 km away from the Indian Ocean, and they have existed for millions of years. Diversity of both fauna and flora is very high in these relicts and the coastal forests of Eastern Africa, extending along the coast from Somalia through Kenya and Tanzania to Mozambique, are ranked among the priority biodiversity hotspot in the world. In spite of the high plant species richness and their importance towards supporting the livelihoods of the communities that live around them, floristic studies in these forests have remained poorly investigated. Hence, based on numerous field investigations, plant lists from published monograph/literature, and data from BRAHMS (Botanical Records and Herbarium Management System) database at East African herbarium (EA), we present a detailed checklist of vascular plants recorded in this region. Our results show that Kenyan coastal forests play an essential role in the flora of Kenya and the plant diversity of the coastal forests of East Africa. The checklist represents 176 families, 981 genera, 2489 species, 100 infraspecific taxa, 90 endemic plants species, 72 exotic species, and 120 species that are included in the current IUCN Red List of Threatened Species as species of major concern. We also discovered three new species to the world from these relicts. Thus, Kenyan coastal forests present a remarkable and significant center of plant diversity.

Abundance, Distribution, Habitat, Activity and Conservation of Sokoke Bushy-Tailed Mongoose Bdeogale omnivora in Central and North Coast Forests of Kenya

The Sokoke dog or bushy-tailed mongoose Bdeogale omnivora is poorly known and considered to be endemic to the East African coastal forests. Systematic camera trap surveys, comprising 9229 camera trap days on grids at six study sites, were used to determine the distribution and relative abundance of the Sokoke bushy-tailed mongoose in the two largest Kenyan coastal forests: Boni-Dodori Forest Complex (ca. 4000 km²); and Arabuko-Sokoke Forest Reserve (416 km²). This species was captured in all surveyed forests with significantly more detections in Brachystegia woodland habitat ( ca . 71 km 2 ) of Arabuko-Sokoke and the Boni forest sectors (ca. 2000 km 2 ) of the Boni-Dodori Forest Complex. Boni-Dodori Forest Complex, with an estimated occupancy of over 60% for this species, holds a significant population. The study generated over 1000 images of the Sokoke bushy-tailed mongoose in a total surveyed area of approximately 500 km 2 providing the first 24-hour activity data for the species. The circadian patterns confirm this species to be strictly nocturnal. This study strongly recommends that its Red List status remains ‘Vulnerable’. The few remaining coastal forests continue to face human pressure. Recent proposals to find and extract hydrocarbons from under the Arabuko-Sokoke Forest, and the planned major development close to Boni-Dodori Forest Complex, raise serious conservation concerns for this exceptionally biodiverse ecosystem. Keywords: Arabuko-Sokoke forest, Boni forest, Dodori forest, camera trap, status, Bdeogale omnivora

Bird responses to land use change: guild diversity in a Kenyan coastal forest and adjoining habitats

ABSTRACTLand use change can have profound effects on forest ecology, particularly on the avian community. Arabuko-Sokoke Forest, one of the Important Bird Areas (IBAs) in Kenya, is under threat due to ongoing land use change in the surroundings that could affect species composition of many bird guilds. However, information on the response of different guilds in tropical land use systems is sparse in Africa. We examined the effects of land use on bird guilds in primary forest (Arabuko-Sokoke Forest), adjoining plantations, and neighbouring farmland. Point counts were distributed equally in the three land use systems to survey bird populations. A total of 2600 bird observations was recorded, representing 97 species in five main feeding guilds (frugivores, nectarivores, insectivores, carnivores, and granivores). Granivores were most abundant and diverse in farmland, while carnivores (primarily raptors) utilised all habitats. Insectivores were most diverse in primary forest where vertical heterogeneity of the vegetation and the presence of large fruiting trees significantly influenced their occurrence. Specialist nectarivores were most frequent in primary forest, whereas occasional nectarivores were less abundant there. Contrary to expectation, frugivore diversity showed no significant effect of land use.

Dovyalis keniensis(Salicaceae), a new species from the coastal forests of Kenya

SummaryDovyalis keniensis E. V. Williams (Salicaceae) is described as a new species from the coastal forests of Kenya. The species is illustrated, its distribution mapped and conservation status assessed. It is compared with D. mollis (Oliv.) Warb. and D. hispidula Willd. A key to the four species of Dovyalis in Kenya is presented.

Adenia angulosa (Passifloraceae), a new species from coastal forests of Kenya and Tanzania

Adenia angulosa, a new species of Passifloraceae from coastal forests of Kenya and Tanzania is described and illustrated with photographs. It is most similar to A. gummifera, but differs by its angled older stem, leaf shape, fewer flowers per inflorescence, connation of filaments, shape of ovary and fruit, as well as size and shape of seed.

Status and Behavioural Ecology of Sengis in the Boni-Dodori and Arabuko-Sokoke Forests, Kenya, Determined by Camera Traps

ABSTRACT The biodiversity of northern coastal Kenya, east of the Tana River, is poorly understood because security problems and poor infrastructure have discouraged access to the area. However, the wooded areas in the region have great potential for harbouring endemic and rare species, including sengis or elephant-shrews (order Macroscelidea), especially giant sengis in the genus Rhynchocyon. Based on extensive camera-trap surveys of the Boni-Dodori forest, east of the Tana River near the Somalia border, and the Arabuko-Sokoke forest west of the Tana River, the goldenrumped sengi Rhynchocyon chrysopygus appears to be limited to the Arabuko-Sokoke area, while the giant sengi in the Boni-Dodori forest is different. The Boni-Dodori forest, the largest Kenyan coastal forest, with a potential forest and thicket area of at least 3000 km2 is likely to hold a significant number of Rhynchocyon, making it very important to sengi conservation. The study generated over 2700 images of giant sengi and 32 000 camera-tra...

Globally Threatened Biodiversity of the Eastern Arc Mountains and Coastal Forests of Kenya and Tanzania

ABSTRACT We present an account of the 909 globally threatened taxa (793 species, 74 subspecies, 42 varieties) of animals and plants in the Eastern Arc Mountains and Coastal Forests of Kenya and Tanzania and the sites in which they occur based upon a review of the 2015 IUCN Red List of Threatened Species. Results for animals are summarised by Class (Amphibia, Aves, Gastropoda, Insecta, Malacostraca, Mammalia, Reptilia) and presented for plants as a whole (Classes Bryopsida, Cycadopsida, Jungermanniopsida, Liliopsida, Lycopodiopsida, Magnoliopsida, Pinopsida, Polypodiopsida). We analyse the status of previously known and newly identified sites in which globally threatened biodiversity occurs and summarise the current state of research on the globally threatened and ecologically critical biodiversity of the EACF. We then provide recommendations for future research, environmental regulations, and management regimes based upon comprehensive and reliable data to ensure the continued survival of the EACF's biodi...

Trends in forest condition, threats and conservation action as derived from participatory monitoring in coastal Kenya

AbstractThe coastal forests of Kenya are conservation priorities hosting high levels of biodiversity. Monitoring of biodiversity in these forests is therefore necessary to understand and reverse negative trends in good time. Using the Important Bird Area (IBA) monitoring framework, a participatory approach, state (habitat condition), pressure (threats) and response (conservation action) indicators of twelve coastal Kenya forest IBAs were assessed from 2004 to 2011. Trends for these indicators were assessed at six sites for which sufficient data existed: Arabuko‐Sokoke, Dakatcha Woodlands, Gede Ruins, Lower Tana River, Shimba Hills and Taita Hills, and baselines were described for remaining six. Changes were always small, but state deteriorated in Gede, Lower Tana and Shimba Hills, remained the same (unfavourable) in Arabuko‐Sokoke and Dakatcha, and improved in Taita Hills. Pressure reduced in Arabuko‐Sokoke, Dakatcha and Taita Hills, deteriorated in Lower Tana and Shimba Hills and remained the same (medium) in Gede. Response improved in Dakatcha, remained the same (medium) in Shimba Hills, and deteriorated in the rest. As there was an apparent overall deterioration in the forests assessed, improved management of the protected sites and increased conservation action through community engagement around protected areas and within the nonprotected IBAs are recommended.

The northern coastal forests of Kenya are nationally and globally important for the conservation of Aders’ duiker Cephalophus adersi and other antelope species

Aders’ duiker Cephalophus adersi is a critically endangered small antelope endemic to the coastal forests of east Africa. Threatened by habitat loss and hunting, the species was until recently known to persist only on Zanzibar, Tanzania, and in the Arabuko-Sokoke National Reserve, Kenya. However, more recent observations, have confirmed the occurrence of Aders’ duiker in Kenyan coastal forests north of the Tana River. This paper reports systematic camera trapping results for three sites in the Boni–Dodori coastal forest system north of the Tana and the only other known mainland site for Aders’ duiker, the Arabuko-Sokoke forest. From a total survey effort of 5,723 camera trap days, we demonstrated that the known area of occurrence for Aders’ duiker has more than doubled with occupancy values at or close to 100 % for all three northern sites. An index of relative abundance for Aders’ duiker was also one to two orders of magnitude greater at these sites compared to Arabuko-Sokoke. Application of a replicate count N-mixture model to camera trap data from Boni National Reserve resulted in an estimate of 7.3 Aders’ duikers/km2 (95 % CI 4.5–10.1/km2). The results also indicate higher densities of suni Nesotragus moschatus and Harvey’s duiker Cephalophus harveyi in the northern forests relative to Arabuko-Sokoke. Blue duiker Philantomba monticola was recorded at low density in Arabuko-Sokoke forest but not detected at the northern sites. These findings significantly improve the conservation prospects for Aders’ duiker and highlight the global importance of the northern coastal forests of Kenya.

Wolbachia, Sodalis and trypanosome co-infections in natural populations of Glossina austeni and Glossina pallidipes

BackgroundTsetse flies harbor at least three bacterial symbionts: Wigglesworthia glossinidia, Wolbachia pipientis and Sodalis glossinidius. Wigglesworthia and Sodalis reside in the gut in close association with trypanosomes and may influence establishment and development of midgut parasite infections. Wolbachia has been shown to induce reproductive effects in infected tsetse. This study was conducted to determine the prevalence of these endosymbionts in natural populations of G. austeni and G. pallidipes and to assess the degree of concurrent infections with trypanosomes.MethodsFly samples analyzed originated from Kenyan coastal forests (trapped in 2009–2011) and South African G. austeni collected in 2008. The age structure was estimated by standard methods. G. austeni (n=298) and G. pallidipes (n= 302) were analyzed for infection with Wolbachia and Sodalis using PCR. Trypanosome infection was determined either by microscopic examination of dissected organs or by PCR amplification.ResultsOverall we observed that G. pallidipes females had a longer lifespan (70 d) than G. austeni (54 d) in natural populations. Wolbachia infections were present in all G. austeni flies analysed, while in contrast, this symbiont was absent from G. pallidipes. The density of Wolbachia infections in the Kenyan G. austeni population was higher than that observed in South African flies. The infection prevalence of Sodalis ranged from 3.7% in G. austeni to about 16% in G. pallidipes. Microscopic examination of midguts revealed an overall trypanosome infection prevalence of 6% (n = 235) and 5% (n = 552), while evaluation with ITS1 primers indicated a prevalence of about 13% (n = 296) and 10% (n = 302) in G. austeni and G. pallidipes, respectively. The majority of infections (46%) were with T. congolense. Co-infection with all three organisms was observed at 1% and 3.3% in G. austeni and G. pallidipes, respectively. Eleven out of the thirteen (85%) co-infected flies harboured T. congolense and T. simiae parasites. While the association between trypanosomes and Sodalis infection was statistically significant in G. pallidipes (P = 0.0127), the number of co-infected flies was too few for a definite conclusion.ConclusionsThe tsetse populations analyzed differed in the prevalence of symbionts, despite being sympatric and therefore exposed to identical environmental factors. The density of infections with Wolbachia also differed between G. austeni populations. There were too few natural co-infections detected with the Sodalis and trypanosomes to suggest extensive inter-relations between these infections in natural populations. We discuss these findings in the context of potential symbiont-mediated control interventions to reduce parasite infections and/or fly populations.

A new population of the Critically Endangered Aders’ duiker Cephalophus adersi confirmed from northern coastal Kenya

AbstractAders’ duiker Cephalophus adersi is a small antelope endemic to the coastal forests of east Africa. Threatened by habitat loss and hunting, the species is categorized as Critically Endangered on the IUCN Red List. Until recently Aders’ duiker was known to persist only on Zanzibar, Tanzania, and in the Arabuko-Sokoke Forest National Reserve, Kenya. However, in 2004 a sighting of a single individual was reported from the Dodori forest in northern coastal Kenya, raising the possibility that the species survives elsewhere. Subsequently, an opportunistic camera-trap survey was conducted in September and October 2008 to establish the occurrence of Aders’ duiker in Kenyan coastal forests north of the Tana River. One hundred and fifty six images of Aders’ duikers were obtained from 12 of 28 camera-trap sites (46 of 358 camera-trap days), confirming the existence of a population of Aders’ duiker in the Boni–Dodori forest both inside and outside the National Reserves. In addition, we sighted individuals of the species on three occasions. The relatively high encounter rates per unit effort compared to similar data from Arabuko-Sokoke forest suggest the Boni–Dodori population is significant. Initial surveys of the local Awer community revealed that Aders’ duiker is well known by the name guno. These findings significantly improve the conservation prospects for Aders’ duiker and highlight the need for greater research and management efforts in the poorly known Boni–Dodori forest.

Plant communities, species diversity, richness, and regeneration of a traditionally managed coastal forest, Kenya

The Kenyan coastal forests make up one of the World 25 Biodiversity Hotspots. They consist of over 140 fragments (the majority with areas less than 0.5 km 2) of the once extensive Zanzibar–Inhambane lowland moist forest. The over 60 known Mijikenda sacred Kaya forests and groves scattered along the coastal hinterland form the greater part of this ecosystem. The forests are of biological and cultural significance, and this has been recognized nationally and internationally, with some now listed as World Heritage Sites. The forests are protected by councils of Kaya elders who regulate use of their resources. Increasing human population and subsequent rise in demand for forest products and land for settlement has put a strain on these relic forests. Farm encroachment and extraction of forest products in different Kaya forests have affected the vegetation ecology at varying levels. This study investigated the spatial species distribution, association and regeneration potential of commonly utilized plants in one of these traditionally managed ecosystems. A modified nested plot method was used to collect data in the field. Using TWINSPAN multivariate, and indicator species analysis, two plant communities ( Asteranthe and Bridelia) and an undifferentiated vegetation type were identified. Species association in Asteranthe consisted largely of forest dependant species, with a significant presence of woody climbers. It was comprised of two sub-communities namely Manilkara and Scorodophloeos. In contrast the second plant community, Bridelia, was dominated by light demanding species. It comprised one sub-community ( Catunaregam) and a seral stage ( Keetia). The species diversity and richness was higher in the Asteranthe community compared to Bridelia. Some of the forest species commonly utilized by the local people were observed to regenerate both in open and closed forest habitats while others had seedling recruitment confined to closed forest. Despite some coastal forests showing physiognomic similarity, detailed study shows intra-variation linked to topography, exposition, type and intensity of human perturbation both currently and in the distant past. Clearly, vegetation patterns of coastal forests of eastern Africa change at fairly short intervals. Recruitment of forest specialists is likely to decline if closed forests are opened up by farm encroachment, however their less specialized counterparts can pioneer in re-colonization of disturbed sites if conservation is strengthened. There is need to invigorate traditional management systems of forests with cultural significance by recognizing and giving increased legal mandates to the local custodians.

A Revision of Afrotropical Quasimodo Flies (Diptera: Curtonotidae: Schizophora). Part II — The East African Afromontane GenusTigrisomyiagen. n., with Descriptions of Four New Species

A new East Africa genus, Tigrisomyia Kirk-Spriggs gen. n., is described; being apparently restricted to high-elevation Afromontane forests associated with the Malawi Rift and Eastern Arc mountain group of Kenya and Tanzania. A diagnosis of the genus is provided and character states (synapomorphies) distinguishing the genus from other genera in the Curtonotidae are outlined. Four new species are described; and are illustrated using pen and ink drawings and light microscopy, namely T. amnoni Kirk-Spriggs, sp. n. (Malawi, Tanzania and Zambia), T. kinskii Kirk-Spriggs, sp. n. (Malawi), T. rhayaderi Kirk-Spriggs, sp. n. (Kenya and Malawi) and T. scoliosis Kirk-Spriggs, sp. n. (Tanzania); the first-named species being designated as type-species for the genus. An identification key to the four species is provided based on external characters. The distribution of the four species is mapped, indicating that T. rhayaderi sp. n. has a disjunct distribution on the Zomba Plateau (Malawi) and coastal forests of Kenya; T. kinskii sp. n. is apparently restricted to Ntchisi Forest (Malawi), and T. kinskii sp. n. to the Rebeho (Usagara) Mountains in the Eastern Arc group. Tigrisomyia amnoni sp. n. is more widely distributed occurring from the West Usambara Mountains in the north of Tanzania to the Zomba Plateau in the Shire District of southern Malawi (and some intervening relict forests). The historical biogeographical significance of the distribution of the four species is discussed in relation to historical pan-African forest cover in Africa.

The biogeographical assignment of a west Kenyan rain forest remnant: further evidence from analysis of its reptile fauna.

Aim The Kakamega Forest, western Kenya, has been biogeographically assigned to both lowland and montane forest biomes, or has even been considered to be unique. Most frequently it has been linked with the Guineo‐Congolian rain forest block. The present paper aims to test six alternative hypotheses of the zoogeographical relationships between this forest remnant and other African forests using reptiles as a model group. Reptiles are relatively slow dispersers, compared with flying organisms (Aves and Odonata) on which former hypotheses have been based, and may thus result in a more conservative biogeographical analysis. Location Kakamega Forest, Kenya, Sub‐Saharan Africa. Methods The reptile diversity of Kakamega Forest was evaluated by field surveys and data from literature resources. Faunal comparisons of Kakamega Forest with 16 other African forests were conducted by the use of the ‘coefficient of biogeographic resemblance’ using the reptile communities as zoogeographic indicators. Parsimony Analysis of Endemism and Neighbour Joining Analysis of Endemism were used to generate relationship trees based on an occurrence matrix with paup*. Results The analysis clearly supports the hypothesis that the Kakamega Forest is the easternmost fragment of the Guineo‐Congolian rain forest belt, and thus more closely related to the forests of that Central–West African complex than to any forest further east, such as the Kenyan coastal forests. Many Kenyan reptile species occur exclusively in the Kakamega Forest and its associated forest fragments. Main conclusions The Kakamega Forest is the only remnant of the Guineo‐Congolian rain forest in the general area. We assume that the low degree of resemblance identified for the Guineo‐Congolian forest and the East African coastal forest reflect the long history of isolation of the two forest types from each other. Kenyan coastal forests may have been historically connected through forest ‘bridges’ of the southern highlands with the Congo forest belt, allowing reptile species to migrate between them. The probability of a second ‘bridge’ located in the region of southern Tanzanian inselbergs is discussed. Although not particularly rich in reptile species, the area should be considered of high national priority for conservation measures.

A New Species of Cola (Sterculiaceae) from the Usambara Mountains, Tanzania

Cola lukei Cheek is described from the Usambara Mts, Tanzania, and its affinities with species in the Kenyan coastal forest and the Udzungwa Mts of Tanzania are discussed.