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Based on recent taxonomic and molecular tools, the Walter's duiker (Philantomba walteri Colyn, 2010), endemic to the Dahomey Gap in West Africa, has been recognized as a new species in 2010. This species is largely hunted and may already be threatened by extinction. This review paper aims to synthesize the current knowledge on this species, covering its taxonomy, morphology, biology, ecology, diet, seed dispersal role, reproduction patterns, activity rate, parasitology, spatial distribution, habitats, population densities, and ongoing human pressures. We carried out an exhaustive literature search using nine databases, going through 1200 initial references to finally retain a total of only 11 research articles mentioning Walter's duiker. Very few publications exist on the species due to its recent discovery. Existing studies focus on feeding, parasitology, and hunting pressure. Walter's duiker distribution range extends over Togo, Benin, and Nigeria. The species is hunted in a large part of its range, including in the reserves that are supposed to protect it. We synthesize the biological information related to the Maxwell's duiker as well as the Walter's duiker, as historically, these two species have been confounded and are morphologically similar. Our synthesis also highlights the scientific gaps for a better understanding of the biology of this species, and it proposes priority themes for future research. Priority should be given to studying the diet composition of Walter's duiker by analyzing rumens and feces, its role in seed dispersal and forest regeneration, its home range and activity rate, and the estimation of its abundance. All these information together would allow to thoroughly assess the species status and contribute to its conservation. [ABSTRACT FROM AUTHOR]

Khaya (Meliaceae) is a widespread genus of trees distributed from the tropical forests of Africa to Madagascar and the Comoros. Khaya species are very close morphologically and some contain considerable phenotypic and ecological diversity, raising the question of their delimitation: this is the case of Khaya anthotheca s.l. (sensu lato, including K. nyasica), which is often lumped with K. grandifoliola and K. ivorensis. We tested species delimitation within K. anthotheca by combining population‐genetic and morphological data. First, a visual inspection of over a thousand specimens suggested the existence of five morphogroups. Second, after genotyping 498 samples at 71 nuclear SNPs, Bayesian clustering analyses (STRUCTURE) first identified five genetic clusters (K1–K5), while further analyses subdivided K5 into two clusters. The six genetic clusters obtained are distributed in parapatry or allopatry from West Africa to East Africa, except for cluster K4, which is in sympatry with K3 in Central Africa. The partitioning of genetic clusters is also largely congruent with the morphogroups identified. The morphological differentiation of these clusters was confirmed by statistical analyses of 27 leaf characters. The clear‐cut genetic differentiation between clusters, with few admixed genotypes even in contact zones, argues for the recognition of distinct species following the biological species concept. Our analyses highlight that the current taxonomic treatment of Khaya underestimates by one‐half the total number of species. We identify two new species, circumscribe K. anthotheca and support the rehabilitation at the rank of species of three taxa considered to be synonyms of K. anthotheca (K. agboensis, K. euryphylla, K. nyasica). These results illustrate the strength of combining population‐genetic and morphological data to delineate an African rainforest tree species complex. [ABSTRACT FROM AUTHOR]

Copyright of Biotropica 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.)

Temporal and spatial patterns in flowering phenology were assessed for eight tropical African tree species. Specifically, the frequency and seasonality of flowering at seven sites in central Africa were determined using field data, graphical analysis and circular statistics. Additionally, spatial variation in the timing of flowering across species range was investigated using herbarium data, analysing the relative influence of latitude, longitude and timing of the dry season with a Bayesian circular generalized linear model. Annual flowering was found for 20 out of the 25 populations studied. For 21 populations located at the north of the climatic hinge flowering was occurring during the dry season. The analysis of herbarium collections revealed a significant shift in the timing of flowering with latitude for E. suaveolens, and with the timing of the dry season for M. excelsa (and to a lesser extent L. alata), with the coexistence of two flowering peaks near the equator where the distribution of monthly rainfall is bimodal. For the other species, none of latitude, longitude or timing of the dry season had an effect on the timing of flowering. Our study highlights the need to identify the drivers of the flowering phenology of economically important African tree species. [ABSTRACT FROM AUTHOR]

Premise: Few studies have addressed the evolutionary history of tree species from African savannahs. Afzelia contains economically important timber species, including two species widely distributed in African savannahs: A. africana in the Sudanian region and A. quanzensis in the Zambezian region. We aimed to infer whether these species underwent range fragmentation and/or demographic changes, possibly reflecting how savannahs responded to Quaternary climate changes. Methods: We characterized the genetic diversity and structure of these species across their distribution ranges using nuclear microsatellites (SSRs) and genotyping‐by‐sequencing (GBS) markers. Six SSR loci were genotyped in 241 A. africana and 113 A. quanzensis individuals, while 2800 high‐quality single nucleotide polymorphisms (SNPs) were identified in 30 A. africana individuals. Results: Both species appeared to be mainly outcrossing. The kinship between individuals decayed with the logarithm of the distance at similar rates across species and markers, leading to relatively small Sp statistics (0.0056 for SSR and 0.0054 for SNP in A. africana, 0.0075 for SSR in A. quanzensis). The patterns were consistent with isolation by distance expectations in the absence of large‐scale geographic gradients. Bayesian clustering of SSR genotypes did not detect genetic clusters within species. In contrast, SNP data resolved intraspecific genetic clusters in A. africana, illustrating the higher resolving power of GBS. However, these clusters revealed low levels of differentiation and no clear geographical entities, so that they were interpreted as resulting from the isolation by distance pattern rather than from past population fragmentation. Conclusions: These results suggest that populations have remained connected throughout the large, continuous savannah landscapes. The absence of clear phylogeographic discontinuities, also found in a few other African savannah trees, indicates that their distribution ranges have not been significantly fragmented during the climatic oscillations of the Pleistocene, in contrast to patterns commonly found in African rainforest trees. [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.)

This study evaluates the characteristics of soil seed bank in two types of central African rainforests: Celtis forest on clay soils and Manilkara forest on sandy soils. In each study site, 30 samples were collected per soil layers (litter, 0–5 cm, 5–10 cm and 10–20 cm depth). The species diversity and abundance of the soil seed bank were estimated after soil samples were brought to germination. We globally observed 297 seedlings of 53 species for the Celtis forest and 222 seedlings of 39 species for the Manilkara forest. The total densities of germinated seeds were 330 seedlings m −2 and 247 seedlings m −2 , respectively. Herbaceous species dominated with percentages of 41.0 and 45.3%, respectively in the Manilkara forest and the Celtis forest. Both forest types displayed a regeneration potential through the soil seed bank. However, this potential seems higher in the Celtis forest. Pioneer taxa were more abundant in the soil seed bank of the Celtis forest (13 woody pioneer species) than the Manilkara forest (9 woody pioneer species). The values of Sorensen similarity index between the standing tree vegetation and the soil seed bank in each site were relatively low: 11.0% for the Celtis forest and 8.8% for the Manilkara forest. But these similarity values were higher when only the pioneer species were considered: 46.8% in the Celtis forest and 38.9% in the Manilkara forest. The highest species richness were obtained in the first two soil layers (0–10 cm depth) while 21.8% and 21.4% of the species were exclusively found in the deepest layer (10–20 cm) in the Celtis forest and the Manilkara forest, respectively. Among the timber species found in the forest, only three were observed in the soil seed bank of the two sites: Nauclea diderrichii , Erythrophleum suaveolens and Staudtia kamerunensis . N . diderrichii was particularly abundant in the soil seed stock of the two sites (14.4–34.4 seeds m −2 ). Results suggested that to improve regeneration of timber species, planting in open forest habitats with seedlings coming from tree nursery should be more efficient. [ABSTRACT FROM AUTHOR]

Background: Species delimitation in closely related plant taxa can be challenging because (i) reproductive barriers are not always congruent with morphological differentiation, (ii) use of plastid sequences might lead to misinterpretation, (iii) rare species might not be sampled. We revisited molecular-based species delimitation in the African genus Milicia, currently divided into M. regia (West Africa) and M. excelsa (from West to East Africa). We used 435 samples collected in West, Central and East Africa. We genotyped SNP and SSR loci to identify genetic clusters, and sequenced two plastid regions (psbA-trnH, trnC-ycf6) and a nuclear gene (At103) to confirm species' divergence and compare species delimitation methods. We also examined whether ecological niche differentiation was congruent with sampled genetic structure. Results: West African M. regia, West African and East African M. excelsa samples constituted three well distinct genetic clusters according to SNPs and SSRs. In Central Africa, two genetic clusters were consistently inferred by both types of markers, while a few scattered samples, sympatric with the preceding clusters but exhibiting leaf traits of M. regia, were grouped with the West African M. regia cluster based on SNPs or formed a distinct cluster based on SSRs. SSR results were confirmed by sequence data from the nuclear region At103 which revealed three distinct 'Fields For Recombination' corresponding to (i) West African M. regia, (ii) Central African samples with leaf traits of M. regia, and (iii) all M. excelsa samples. None of the plastid sequences provide indication of distinct clades of the three species-like units. Niche modelling techniques yielded a significant correlation between niche overlap and genetic distance. Conclusions: Our genetic data suggest that three species of Milicia could be recognized. It is surprising that the occurrence of two species in Central Africa was not reported for this well-known timber tree. Globally, our work highlights the importance of collecting samples in a systematic way and the need for combining different nuclear markers when dealing with species complexes. Recognizing cryptic species is particularly crucial for economically exploited species because some hidden taxa might actually be endangered as they are merged with more abundant species. [ABSTRACT FROM AUTHOR]

Palaeoecological and archaeological studies have demonstrated that human populations have long inhabited the moist forests of central Africa. However, spatial and temporal patterns of human activities have hardly been investigated with satisfactory accuracy. In this study, we propose to characterize past human activities at local scale by using a systematic quantitative and qualitative methodology based on soil charcoal and charred botanical remains. A total of 88 equidistant test-pits were excavated along six transects in two contrasting forest types in southern Cameroon. Charred botanical remains were collected by water-sieving and sorted by type (wood charcoals, oil palm endocarps and unidentified seeds). A total of 50 Accelerator Mass Spectrometry 14C dates were also obtained. Results showed that charred macroremains were found at multiple places in the forest, suggesting scattered human activities, which were distributed into two main periods (Phase A: 2300–1300 BP; Phase B: 580 BP to the present). Charred botanical remains indicated two types of land-use: (1) domestic, with oil palm endocarps most often associated with potsherds (villages) and (2) agricultural, with charcoal as probable remnant of slash-and-burn cultivation (fields). Oil palm endocarp abundance decreased with distance from the identified human settlements. Our methodology allowed documenting, at high resolution, the spatial and temporal patterns of human activities in central African moist forests and could be applied to other tropical contexts. [ABSTRACT FROM AUTHOR]

In natural forests of Central Africa, several studies indicate a dramatic decrease in commercial trees, including species of concern for conservation. Enrichment planting with these species will favor both the long-term recovery of their populations and biodiversity conservation in logged forests. In this study, we analyzed the survival and growth of 23 species in plantations. Fourteen 0.2–1.1 ha mixed species plantations consisting of single-species 15 × 15 m blocks were studied for 5 years in a logging concession of southeastern Cameroon. The plantation design considered both species light requirements and sensitivity to damage by pests. To identify the best species for enrichment planting, we assessed both species performance and plantation costs. We also tested for relationships between species traits and species performance. Mean annual diameter growth increments ranged from 1.67 to 42.9 mm. No significant relationship was found between growth and survival. Herbivory by wild Bovidae was the main cause of mortality and should be carefully considered in rehabilitation efforts. We found a significant negative relationship between wood density and maximum growth rate. The other traits tested were not good predictors of species performance in plantations. The two best-performing species,Triplochiton scleroxylonandTerminalia superba, could reach the minimum cutting diameter during a 30-year cutting cycle. Costs were high and mechanized site preparation is suggested to reduce them. Widespread adoption of such plantations will only occur if financial incentives or national regulations for assuring regeneration are implemented. EDITED BY Nicholas Brokaw [ABSTRACT FROM PUBLISHER]

To develop silvicultural guidelines for high-value timber species of Central African moist forests, we assessed the performance of the pioneer Milicia excelsa (iroko, Moraceae), and of the non-pioneer light demander Pericopsis elata (assamela, Fabaceae) in logging gaps and in plantations in highly degraded areas in south-eastern Cameroon. The survival and size of each seedling was regularly monitored in the silvicultural experiments. Differences in performance and allometry were tested between species in logging gaps and in plantations. The two species performance in logging gaps was significantly different from plantations and concurred with the expectations of the performance trade-off hypothesis but not with the expectations of species light requirements. The pioneer M. excelsa survived significantly better in logging gaps while the non-pioneer P. elata grew significantly faster in plantations. The high mortality and slow growth of M. excelsa in plantations is surprising for a pioneer species but could be explained by herbivory (attacks from a gall-making psyllid). Identifying high-value native timber species (i) with good performance in plantations such as P. elata is of importance to restore degraded areas; and (ii) with good performance in logging gaps such as M. excelsa is of importance to maintain timber resources and biodiversity in production forests. [ABSTRACT FROM AUTHOR]

While most past studies have emphasized the relationships between specific forest stands and edaphic factors, recent observations in Central African moist forests suggested that an increase of slash-and-burn agriculture since 3000-2000 BP (Before Present) could be the main driver of the persistence of light-demanding tree species. In order to examine anthropogenic factors in the persistence of such populations, our study focused on Pericopsis elata, an endangered clustered timber species. We used a multidisciplinary approach comprised of botanical, anthracological and archaeobotanical investigations to compare P. elata patches with surrounding stands of mixed forest vegetation ("out-zones"). Charcoal samples were found in both zones, but were significantly more abundant in the soils of patches. Eleven groups of taxa were identified from the charcoals, most of them also present in the current vegetation. Potsherds were detected only inside P. elata patches and at different soil depths, suggesting a long human presence from at least 2150 to 195 BP, as revealed by our charcoal radiocarbon dating. We conclude that current P. elata patches most likely result from shifting cultivation that occurred ca. two centuries ago. The implications of our findings for the dynamics and management of light-demanding tree species are discussed. [ABSTRACT FROM AUTHOR]

In central Africa, most of the timber species require high light at the seedling stage for survival and growth. Forest managers face a regeneration shortage of these light-demanding timber species. To achieve long-term sustainability, there is a need for enrichment methods combining low cost and high species performance. The aim of this study was to assess the performance of Pericopsis elata seedlings in enriched logging gaps in Cameroon. Over five years; the survival and size of each seedling was monitored in 27 logging gaps that were either left without maintenance or cleared. Gaps were relatively small with an average total area of 155 m2. We found that planted seedlings of P. elata performed well in logging gaps. Even without any maintenance 61% of the planted seedlings survived after five years with an average annual diameter increment of 0.28 cm. P. elata appeared to be a good candidate species for enrichment in logging gaps. We demonstrated that the seedlings of P. elata tolerated a wide range of soil conditions but that their performance was strongly influenced by light availability (gap clearance), suggesting potentially improved performance of P. elata in high light environments such as in plantation or larger gaps. [ABSTRACT FROM AUTHOR]

The canopy of many central African forests is dominated by light-demanding tree species that do not regenerate well under themselves. The prevalence of these species might result from ancient slash-and-burn agricultural activities that created large openings, while a decline of these activities since the colonial period could explain their deficit of regeneration. To verify this hypothesis, we compared soil charcoal abundance, used as a proxy for past slash-and-burn agriculture, and tree species composition assessed on 208 rainforest 0.2 ha plots located in three areas from Southern Cameroon. Species were classified in regeneration guilds (pioneer, non-pioneer light-demanding, shade-bearer) and characterized by their wood-specific gravity, assumed to reflect light requirement. We tested the correlation between soil charcoal abundance and: (i) the relative abundance of each guild, (ii) each species and family abundance and (iii) mean wood-specific gravity. Charcoal was found in 83% of the plots, indicating frequent past forest fires. Radiocarbon dating revealed two periods of fires: “recent” charcoal were on average 300 years old (up to 860 BP, n = 16) and occurred in the uppermost 20 cm soil layer, while “ancient” charcoal were on average 1900 years old (range: 1500 to 2800 BP, n = 43, excluding one sample dated 9400 BP), and found in all soil layers. While we expected a positive correlation between the relative abundance of light-demanding species and charcoal abundance in the upper soil layer, overall there was no evidence that the current heterogeneity in tree species composition can be explained by charcoal abundance in any soil layer. The absence of signal supporting our hypothesis might result from (i) a relatively uniform impact of past slash-and-burn activities, (ii) pedoturbation processes bringing ancient charcoal to the upper soil layer, blurring the signal of centuries-old Human disturbances, or (iii) the prevalence of other environmental factors on species composition. [ABSTRACT FROM AUTHOR]

Copyright of Tropical Ecology is the property of Springer Nature 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.)

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.)

The impact of the Pleistocene climate oscillations on the structure of biodiversity in tropical regions remains poorly understood. In this study, the forest refuge theory is examined at the molecular level in Milicia excelsa, a dioecious tree with a continuous range throughout tropical Africa. Eight nuclear microsatellites (nSSRs) and two sequences and one microsatellite from chloroplast DNA (cpDNA) showed a deep divide between samples from Benin and those from Lower Guinea. This suggests that these populations were isolated in separate geographical regions, probably for several glacial cycles of the Pleistocene, and that the nuclear gene pools were not homogenized despite M. excelsa's wind-pollination syndrome. The divide could also be related to seed dispersal patterns, which should be largely determined by the migration behaviour of M. excelsa's main seed disperser, the frugivorous bat Eidolon helvum. Within Lower Guinea, a north-south divide, observed with both marker types despite weak genetic structure (nSSRs: FST = 0.035, cpDNA: GST = 0.506), suggested the existence of separate Pleistocene refugia in Cameroon and the Gabon/Congo region. We inferred a pollen-to-seed dispersal distance ratio of c. 1.8, consistent with wide-ranging gene dispersal by both wind and bats. Simulations in an Approximate Bayesian Computation framework suggested low nSSR and cpDNA mutation rates, but imprecise estimates of other demographic parameters, probably due to a substantial gene flow between the Lower Guinean gene pools. The decline of genetic diversity detected in some Gabonese populations could be a consequence of the relatively recent establishment of a closed canopy forest, which could negatively affect M. excelsa's reproductive system. [ABSTRACT FROM AUTHOR]

• We investigated the drivers of great ape distribution in logged tropical forests. • The density of logging roads highly influences habitat selection by primates. • The majority of suitable habitats corresponds to areas logged after 2003. • Suitable habitats were exploited under management plans and RIL practices. • Well managed concessions may be complementary to adjacent protected areas. Negative short-term impact of logging on great ape distribution has been investigated but very little information is available on the long-term impacts of selective logging and management plans on ape habitats at a broader scale. We carried out a habitat suitability analysis using the presence data of great apes to identify the spatial relationships between their locations, logging activities patterns, and other human impacts (due to activities in rural communities) in an FSC-certified forestry concession (388,949 ha) in Cameroon. First, field data showed that the two great ape species, gorilla (Gorilla gorilla gorilla) and chimpanzee (Pan troglodytes troglodytes), did not differ in habitat type selection and they particularly appreciated highly dense rainforests which also lie within selectively logged zones. Second, we used MAXENT software to relate ape presence data to a set of predictor variables which represent environmental conditions and human disturbance factors (poaching, farming, trees felled to collect honey, logging roads). The model predicted that half of the whole concession may be suitable for the two primate species. Disturbances stemming from rural communities mainly correspond to poaching in the framework or not of usage rights. Road density was the strongest predictor of habitat choice by the great apes. Whereas the great apes tend to avoid zones with high road density, their population abundance increases in areas with a certain level of old logging roads. The vast majority of the predicted suitable habitats corresponds to areas logged less than 17 years ago (46.8% of the whole suitable area) where sustainable management practices have begun to be implemented, and unlogged areas (34.30%). Unsuitable habitats were mostly located in areas exploited before 2003 (45.46% of the unsuitable zones) with no reduced-impact logging practices, and in unlogged forests (41.51%). Our findings tend to confirm that selective logging combined with reduced-impact logging techniques which were more prevalent in FSC-certified concessions, may maintain or increase the spatial distribution of great ape habitats. [ABSTRACT FROM AUTHOR]