Distribution et structure des parcs à Adansonia digitata L. (baobab) au Togo (Afrique de l’Ouest)

Les usages diversifiés et rependus des produits surtout à des fins alimentaires du baobab (Adansonia digitata) induits une forte pression sur cette dernière. La présente étude est une contribution à la gestion durable des parcs à A. digitata L. au Togo. Elle a pour objectifs de : (i) déterminer la distribution spatiale des populations à A. digitata et (ii) analyser la structure démographique de ses populations. La méthodologie suivit est basée sur l’inventaire forestier à l’intérieur de 80 placeaux de 50 m x 50 m choisis dans 30 carrés de dimensions 10 km x 10 km. Les paramètres dendrométriques relevés sont : la hauteur totale et le diamètre (dbh ≥ 10 cm) de toutes les espèces ligneuses. Les individus de diamètre < 10 cm sont considérés comme des régénérations potentielles. Au total 52 espèces reparties en 45 genres et 23 familles ont étés recensées. Les familles les plus représentées sont les : Anacardiaceae, Arecaceae, Bombacaceae, Caesalpiniaceae, Moraceae, Rutaceae, Rubiaceae et les Meliaceae. Une classification hiérarchique ascendante des relevés a permis de discriminer 4 parcs à A. digitata : les jardins de case, 2 types de   champs de village et les champs de brousse. L’espèce est plus abondante dans les zones I et II suivie de la zone V, presqu’absente dans la zone IV. La structure en diamètre de l’espèce est en cloche à asymétrique positive avec une prédominance des individus de faible diamètres. Par contre, la structure en diamètre des ligneux des 4 groupements est en « L », montrant une prédominance des individus de très faible diamètre. Compte tenu de l’importance socio-économique de cette espèce, il s’avère nécessaire de mettre des mesures de gestion durable.Mots-clés : parcs à baobab, distribution, structure, Togo

Grain legumes and dryland cereals for enhancing carbon sequestration in semi-arid and sub-humid agro-ecologies of Africa and South Asia

Sorghum, millets (pearl and finger millet) and grain legumes (chickpea, common bean, cowpea, lentils, pigeon pea and soybean), collectively referred to as GLDC under the CGIAR research program on Grain Legumes and Dryland Cereals, are commonly grown, eaten and traded by small holder farmers in Africa and South Asia. These crops contribute to food and nutritional security, environmental sustainability, and economic growth in the region. However, their possible contribution to carbon sequestration through biomass production and accumulation of soil organic carbon (SOC) is not known. To find out more about their contribution, and how to increase SOC, this study reviewed the evidence of carbon sequestration in farming systems that integrate GLDC in Africa and South Asia. A total of 437 publications reporting SOC and its proxies across 32 countries in Africa (N=250 studies) and South Asia (N=187) were identified as sources of evidence for carbon sequestration. Among these, 179 publications provided appropriate control groups for evaluating changes in aboveground carbon when GLDC were integrated under intercrop (n=38), crop rotation (n=8) or agroforestry (n=13), or when improved varieties of GLDC were compared with local varieties (n=14). A further 81 publications compared SOC content at the start and the end of the experiment while 43 publications compared SOC between farms growing GLDC and those which did not. Aboveground carbon of GLDC was found to be 1.51±0.05 Mg/ha in Africa and 2.29±0.10 Mg/ha in South Asia. Absolute SOC concentration in the topsoil (0-30 cm) was 0.96±0.06% in Africa and 0.58±0.04 in South Asia. It was observed that GLDC produced more aboveground carbon and significantly increased SOC when grown as intercrops and in crop rotations. The increase, however, depended on the species and whether the crop was a legume or a cereal. The largest amount of aboveground carbon (>2 Mg/ha) was found in cereals (and pigeon pea) while the largest increase in SOC was found in farming systems that included legumes. Aboveground carbon of improved varieties of GLDC was lower compared to local varieties. Soils which had low initial (32%) showed the greatest potential for carbon sequestration when GLDC were grown. Among the GLDC crops, pigeon pea which is a perennial grain legume showed the highest biomass production and carbon sequestration in the soil when integrated into farming systems in Africa and South Asia. Findings from this study underscore the importance of aboveground residues in regulating the addition of carbon to the soil, and the role of legumes in the enhancement of SOC

Pantropical variability in tree crown allometry

Aim: Tree crowns determine light interception, carbon and water exchange. Thus, understanding the factors causing tree crown allometry to vary at the tree and stand level matters greatly for the development of future vegetation modelling and for the calibration of remote sensing products. Nevertheless, we know little about large‐scale variation and determinants in tropical tree crown allometry. In this study, we explored the continental variation in scaling exponents of site‐specific crown allometry and assessed their relationships with environmental and stand‐level variables in the tropics. / Location: Global tropics. / Time period: Early 21st century. / Major taxa studied: Woody plants. / Methods: Using a dataset of 87,737 trees distributed among 245 forest and savanna sites across the tropics, we fitted site‐specific allometric relationships between crown dimensions (crown depth, diameter and volume) and stem diameter using power‐law models. Stand‐level and environmental drivers of crown allometric relationships were assessed at pantropical and continental scales. / Results: The scaling exponents of allometric relationships between stem diameter and crown dimensions were higher in savannas than in forests. We identified that continental crown models were better than pantropical crown models and that continental differences in crown allometric relationships were driven by both stand‐level (wood density) and environmental (precipitation, cation exchange capacity and soil texture) variables for both tropical biomes. For a given diameter, forest trees from Asia and savanna trees from Australia had smaller crown dimensions than trees in Africa and America, with crown volumes for some Asian forest trees being smaller than those of trees in African forests. / Main conclusions: Our results provide new insight into geographical variability, with large continental differences in tropical tree crown allometry that were driven by stand‐level and environmental variables. They have implications for the assessment of ecosystem function and for the monitoring of woody biomass by remote sensing techniques in the global tropics

Tallo: A global tree allometry and crown architecture database.

This is the final version. Available from Wiley via the DOI in this record. Data capturing multiple axes of tree size and shape, such as a tree's stem diameter, height and crown size, underpin a wide range of ecological research-from developing and testing theory on forest structure and dynamics, to estimating forest carbon stocks and their uncertainties, and integrating remote sensing imagery into forest monitoring programmes. However, these data can be surprisingly hard to come by, particularly for certain regions of the world and for specific taxonomic groups, posing a real barrier to progress in these fields. To overcome this challenge, we developed the Tallo database, a collection of 498,838 georeferenced and taxonomically standardized records of individual trees for which stem diameter, height and/or crown radius have been measured. These data were collected at 61,856 globally distributed sites, spanning all major forested and non-forested biomes. The majority of trees in the database are identified to species (88%), and collectively Tallo includes data for 5163 species distributed across 1453 genera and 187 plant families. The database is publicly archived under a CC-BY 4.0 licence and can be access from: https://doi.org/10.5281/zenodo.6637599. To demonstrate its value, here we present three case studies that highlight how the Tallo database can be used to address a range of theoretical and applied questions in ecology-from testing the predictions of metabolic scaling theory, to exploring the limits of tree allometric plasticity along environmental gradients and modelling global variation in maximum attainable tree height. In doing so, we provide a key resource for field ecologists, remote sensing researchers and the modelling community working together to better understand the role that trees play in regulating the terrestrial carbon cycle.Natural Environment Research Council (NERC)Natural Environment Research Council (NERC); Ministry of Education, Youth and Sports of the Czech RepublicFAPEMIGUniversidad Nacional Autónoma de MéxicoUniversidad Nacional Autónoma de MéxicoConsejo Nacional de Ciencia y TecnologíaSwedish Energy AgencyUKRIFederal Ministry of Education and ResearchNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Science FoundationNational Science FoundationInternational Foundation for ScienceP3FACDynAfForNanjing Forestry UniversityJiangsu Science and Technology Special ProjectHebei UniversityAgence Nationale de la RechercheAgence Nationale de la RechercheAgua Salud ProjectU.S. Department of EnergyCAPE

Distribution et utilites des mauvaises herbes des champs de cultures du campus Universitaire de Lome

Les enquêtes ethnobotaniques réalisées dans la Région Maritime plus précisément dans les champs du Campus universitaire de Lomé ont permis d’avoir une meilleure connaissance des espèces dites mauvaises herbes par les cultivateurs et leur utilisation. Au total, 127 espèces ont été recensées, reparties en 48 familles et 110 genres. Un grand nombre d’utilisations a été enregistré. Ces différentes indications recueillis intègrent aussi bien les usages en médecine traditionnelle que les usages en alimentation, en ébénisteries, en cosmétique et ornementation. Les espèces recensées interviennent dans le traitement de 93 pathologies dont les plus courantes sont le paludisme, ictère, dermatoses et parasitoses intestinales. Bien que considérées comme herbes indésirables, elles sont d’une grande utilité pour la cuisine, l’artisanat et la pharmacopée. Ces résultats d’enquêtes ethnobotaniques sur les mauvaises herbes pourront permettre une orientation éventuelle des recherches en pharmacologie dans la recherche de nouvelles molécules plus actives.Mots clés : Mauvaises herbes, ethnobotanique, pathologies, Région Maritime, Togo.ABSTRACTEthnobotanical surveys in the Maritime region specifically in the fields of Lome Campus allowed to have a better knowledge of such weed species by farmers and their use. A total of 127 species were recorded, distributed in 48 families and 110 genera. A large number of uses was recorded. These various indications collected include both uses in traditional medicine as feed uses, woodworkers in cosmetic and ornamentation. The recorded species involved in the treatment of 93 diseases, the most common are malaria, jaundice, skin diseases and intestinal parasites. Although considered weeds, they are of great use for cooking, crafts and pharmacopoeia. These ethnobotanical surveys of weeds results will allow possible orientation of pharmacology research in search of new, active molecules.Keywords: Weed, ethnobotany, pathologies, Region Maritime, Togo.

Impacts de l’exploitation artisanale de l’or sur les ressources naturelles à Kemeni (région centrale du Togo).

L’exploitation de l’or est devenue ces deux dernières années l’activité principale de la population de Kéméni, une localité située dans la Préfecture de Tchaoudjo (Région Centrale du Togo). La présente étude a identifié l’impact de cette activité sur les ressources naturelles. L’approche méthodologique s’est basée sur des enquêtes couplées aux observations de terrain et complétées par des inventaires floristiques, forestiers et écologiques. Au total 175 personnes dont 143 orpailleurs, 27 riverains et 5 propriétaires terriens ont été enquêtées. 97,69% des enquêtés reconnaissent que l’exploitation artisanale de l’or a occasionné la destruction de la végétation, la déviation du lit de cours d’eau, la dégradation du sol et la pollution de l’eau. Les puits et les grottes laissés ouvert après exploitation rendent les sites d'accès dangereux pour les animaux et pour les hommes. Sur le plan économique, cette activité est la seule source de revenu pour 35,66% des ménages du village. Le revenu moyen par exploitant varie entre 700 F CFA à 2000 F CFA par jour. Les inventaires floristiques ont permis de dénombrer 228 espèces reparties en 178 genres et 61 familles. Les analyses statistiques permettent de discriminer 4 types de végétation : les forêts galeries, les savanes herbeuses, les savanes arborées dégradées et les savanes arborées relativement conservées avec des caractéristiques structurales variables. L’analyse de données d’inventaires forestiers en fonction des groupements discriminés met en évidence l’impact de la dégradation des formations végétales suite aux activités humaines, principalement l’exploitation de l’or sur la structure démographique, la densité, la régénération et la composition floristique. Ainsi la dégradation du couvert végétale surtout des forêts galeries fragilisent les berges des cours d’eaux favorisant l’envasement et l’assèchement de ces derniers. Une mise en place des mesures de sécurité et une étude d'impact environnementale préalable ou accompagnant les activités d’exploitation s’imposent afin de contribuer à une meilleure préservation de l’environnement et de la biodiversité.Mots clés : orpaillage, ressources naturelles, impact, Kéméni, Togo.English AbstractThe gold mining became the last two years the main activity of the population of Kemeni, a village in the prefecture of Tchaoudjo (Central Region of Togo). This study has revealed the impact of this activity on natural resources. The methodological approach is based on surveys coupled with field observations and completed by floral, forestry and ecological inventories. On the whole 175 people including 143 miners, 27 residents and 5 landowners were surveyed. 97.69% of respondents agree that artisanal gold mining has caused the destruction of the vegetation, the diversion of the rivers, soil degradation and water pollution. Wells and caves left open after use, make dangerous the access spots for animals and men. In economic terms, this activity is the only source of income for  35.66% of households in the village. The average income per owners ranges from 700 CFA to 2000 CFA francs per day. Floristic inventories have counted 228 species distributed in 178 genera and 61 families. Statistical analyzes can discriminate four types of vegetation galleries forests, grassland, raised savannas damaged and savanna woodlands degraded relatively conserved with varying structural characteristics. Analysis of forest inventory data according discriminated groups highlights the impact of the degradation of vegetation due to human activities, primarily gold mining on population structure, density, regeneration and floristic composition. So, the degradation of plant mostly gallery forests covered weaken the banks of rivers encourage silting up and drying up of them. An implementation of safety measures and environmental impact study prior or accompanying operations are needed to contribute to a better preservation of the environment and biodiversity.Keywords: gold mining, natural resources, impact, Kemeni, Togo

Soil Health Changes Over a 25-Year Chronosequence From Forest to Plantations in Rubber Tree (Hevea brasiliensis) Landscapes in Southern Côte d'Ivoire: Do Earthworms Play a Role?

The agro-ecological drawbacks of the spread of rubber tree plantations in Côte d'Ivoire since the 1990's are obvious even though they have not been properly investigated. They consist of biodiversity loss, land degradation and food insecurity, which have extended into the existing cocoa-led degraded areas whose rehabilitation have unfortunately not started. This situation increases not only the threat on soil health status but also undermines the capability of soils to deliver ecosystem services that are key to sustainable agricultural production. The current study took advantage of a chronosequence in rubber tree landscapes to assess soil health deterioration in general and possibly earthworm-mediated role in soil health changes. The hypothesis underpinning this study was that earthworms contribute to mitigate soil health deterioration in rubber-dominated landscapes due to their key role in soil functioning. This study confirmed that the conversion of forest to rubber tree plantations significantly impaired all soil biological, physical, and chemical parameters at the beginning (7 years) of the chronosequence; followed further by a restorative trend taking place beneath the plantations from 12 years. However, this study failed to find evidence of a direct role of earthworms in soil health rehabilitation over time. Mesoscale studies along with the use of appropriate models could help unravel this “black box” and shed some light on the contribution of earthworms as key soil ecosystem engineers

An annotated checklist of the birds of Burkina Faso

FIG. 26. — Cinnyris coccinigastrus (Latham, 1801), Comoé-Léraba classified forest, Cascade Region, 20.III.2011 (photo M. Pavia).Published as part of Boano, Giovanni, Belemsobgo, Urbain, Silvano, Fabrizio, Hema, Emmanuel M., Belemsobgo, Aristide, Dimobe, Kangbéni & Pavia, Marco, 2022, An annotated checklist of the birds of Burkina Faso, pp. 27-107 in Zoosystema 44 (2) on page 95, DOI: 10.5252/zoosystema2022v44a2, http://zenodo.org/record/599969