Jean Lejoly

Jean Lejoly
Université Libre de Bruxelles | ULB · Laboratoire de botanique systématique et de phytosociologie

PhD

About

167
Publications
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1,628
Citations
Additional affiliations
May 1968 - present
Université Libre de Bruxelles
Position
  • Professor

Publications

Publications (167)
Article
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Soil fertility transience in the region of Masako in Democratic Republic (RD) of Congo remains a major challenge to sustainable agricultural production. Recently, biochar application as soil amendment has attracted attention of the people across the world owing to its potential to improve soil physicochemical properties, crop yield and carbon seque...
Article
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his ecological study on the pest species Sericostachys scandens in the upland of Kahuzi-Biega National Park took place in 2 sectors of (Tshivanga and Mugaba) where the flora was studied according to whether species are in association with Sericostachys scandens. Some species associate or not with this pest. Most suppressed or decimated species were...
Article
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Cette étude a été conduite à l’Est du Cameroun, dans la forêt communautaire de Payo. Elle a pour objet d’évaluer l’importance écologique, productive et socioéconomique de P. macrophylla. Le dispositif d’inventaire est constitué de quatre transects de 40 m x 2000 m2 (8 ha chacun) avec un taux de sondage de 2%. Toutes les tiges de diamètre à hauteur...
Article
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The present study aims to analyze diversity, structure and effect of rare species rate and relative abundance of the over-represented species on arborescent layers’ diversity in Rubi Tele Domaine de Chasse (RTDC) mature forests. The RTDC (6227.74 km²) straddles the Tshopo and Bas-Uélé provinces in the North-Eastern part of the Democratic Republic o...
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Study of diameter structure of Pterocarpus soyauxii Taub species has been undertaken in Yoko Forest Reserve and Biaro Forest into two permanent dispositive of 400 ha each one. This work has objectives based on density distribution by diameter class and pedological parameters in the two selected sites. All stems of dbh ≥ 10 cm of the studied species...
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The present study was undertaken with the aim of to characterize, according to physiognomic point of view, the vegetation communities in the UMA forest and to evaluate the influence of physico-chemical and pedo-morphological parameters in the spatial organization of floristic diversity in the UMA forest. Five vegetation communities were identified...
Article
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Silica (SiO 2) in forage grasses has been found in reducing cell-wall digestibility. This study investigates whether: (i) the seasonal variability affects the silica and minerals accumulation and forage values of leaves of R. cochinchinensis and (ii) silica concentration is correlated with minerals and fodder value. In an itchgrass population selec...
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Aims: Relationships between local habitat heterogeneity and tree communities in miombo woodlands have been very little studied. While some studies have addressed this topic at broad scales and based on few environmental parameters, this study aims at 1) detecting fine-scale habitats (≤ 10 ha) on the basis of a detailed characterisation of soil expl...
Book
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L’objectif général de cette étude était d’évaluer les potentialités de domestication des populations de T. conophorum afin d’assurer une gestion efficace et une intégration efficiente dans les systèmes agroforestiers. Les investigations ont eu lieu dans les agroforêts à base de cacaoyers du Mbam & Inoubou, qui figure parmi les quatre grands bassins...
Article
Objectives: There is a huge demand for medicinal bark in developing countries and this demand is growing fast due to it high market values. To assess the effects of bark functions and tree capacities to recover from various debarking practices, a two-year experiment was conducted and several local harvest practices were tested on Garcinia lucida.Me...
Article
Description. This article deals with the improvement of the productivity of (poor) sandy and acidic soils in Kinshasa (DRC) using local natural resources in addition to mineral fertilization. Objectives. The objective of this study was to evaluate the effect of ground charcoal (biochar) and Tithonia diversifolia leaves combined with mineral fertili...
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Résumé L’agroforesterie avec Acacia auriculiformis et Acacia mangium au plateau des Bateke, est l’une des techniques recommandées pour ce terroir à vocation agricole, aux sols sableux et pauvres. L’évaluation des effets de ces légumineuses ligneuses sur les macronutriments primaires du sol reste parmi les questions pendantes autour de cette pratiqu...
Article
In order to develop a sustainable farming system adapted to the conditions of the Bateke plateau, a preliminary trial was conducted between January 2012 and March 2013 at the Ibi agro-forestry domain after a fallow of 10 years (the last three years without destruction of the vegetation by bush fires) in sandy soil according to a randomized complete...
Article
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One of the major constraints for the natural replenishment of the fertility of savanna sandy soils is the continual shortening of fallow in the traditional slash and burn system. On the Bateke plateau, agroforestry appeared as one of the alternative systems to cope with soils poverty. This study is a preliminary assessment of soil nutrient contents...
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Etudes floristique et structurale des peuplements sur sols argileux à Pericopsis elata et sableux à Julbernardia seretii dans la forêt de plaine d'UMA en République Démocratique du Congo [ Floristic and structural studies of the settlements on clay soils with Pericopsis elata and sandy with Julbernardia seretii in the UMA plain forest in Democratic...
Article
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Traditional medicine is largely used in Benin and Lubero Territories (D R Congo) as costs for conventional drugs increase and become unaffordable to many people, particularly living in rural areas. The aim of this work is to unlock convergences of plant species used in Bantu and Pygmy herbal medicine. An ethno botanical survey was conducted from 20...
Article
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Cette etude a ete conduite a l'Est du Cameroun, dans la foret communautaire de Payo. Elle a pour objet d'evaluer l'importance ecologique, productive et socioeconomique de P. macrophylla. Le dispositif d'inventaire est constitue de quatre transects de 40 m x 2000 m2 (8 ha chacun) avec un taux de sondage de 2%. Toutes les tiges de diametre a hauteur...
Article
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Le but de cette étude a été d’identifier, d’une part, les Orchidées épiphytes à partir de fleurs d’au moins 500 spécimens vivants et stériles d’Orchidées récoltés dans le district du Mai-Ndombe, mis en culture sousombrière à Kinshasa, sur les planches de Milicia excelsa (Welw.) C.C. Berg et suivis pendant au moins une année jusqu’à leur floraison,...
Article
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Reactualisation of floristic and phytosociologic datas in Niayes and Peanut-Basin areas were undertook with village scale approach to better underline resources' conervation. In Savannah and sub-guinean areas specially in the Peanut-Basin and Niayes, 288 floristic samples were put in place in 6 villages in an stratified way based on ethnic groups,...
Article
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QuestionsSoil properties have been shown to partially explain tree species distribution in tropical forests. Locally, species turnover across space can result not only from edaphic heterogeneities but also from limited seed dispersal. To characterize the contribution of each process, contact areas between contrasted soil types offer ideal settings....
Article
Understanding the phylogenetic structures of plant communities is being developed in community ecology. Based on the species coexistence, we analyzed phylogenetic signals within forest layers, using species abundance data as well as their occurrences (presence/absence) within plots. We found that plant communities in the different forest layers exp...
Article
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RESUME Mots-clés: Analyse spatiale, Caesalpinioideae, Mimosoideae, biais, intensité d'échantillonnage Cette étude cherche à démontrer que la détermination des zones de conservation basée uniquement sur la diversité spécifique et la richesse des espèces endémiques est biaisée par une répartition inégale de la densité de l'échantillonnage à travers l...
Article
Coexistence of species in tropical forests remains an open debate in community ecology. Two main substrates, sandy and clay soils, exist in sites harboring semi-deciduous forests in the central Congo Basin. The way this edaphic heterogeneity affects species occurrences and abundances was investigated. Sampling plots were established on each of the...
Article
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Dans le but d'analyser l'influence de la structure spatiale sur le fonctionnement écologique des écosystèmes forestiers, une étude sur la distribution spatiale, la régénération naturelle et la coexistence des principales espèces arborescentes a été menée dans la réserve naturelle forestière de Bururi au Burundi. Cette aire protégée constitue la par...
Article
Abstract Tetracarpidium conophorum, commonly known as conophor nut or African walnut, is a liana of Euphobiaceae family, usually found in Cameroon and regional countries such as Nigeria, Gabon and Democratic Republic of Congo. This vine provides AFTPs use for a number of purposes including food, medicine and sold to generate income. The Mbam and I...
Article
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The spontaneous undergrowth of teak (Tectona grandis L. f.) plantation in Djigbé forest (south Benin) has been studied. The Psychotria vogeliana-community is identified from ten representative phytosociological relevés. This community is an indicator of sandy plateau soils generally associated with the least productive plantations. It's composed of...
Article
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A list of the orchids of Sao-Tomé and Principe is provided. 129 taxa are listed including 44 taxa supplementary to the previous studies. Furthermore, some observations on the morphological variation are given for Bulbophyllum mediocre Summerh., B. intertextum Lindl, and B. sandersonii (Hook, f.) Rchb. f., Chamaeangis vagans (Lindl.) Schltr., Lipari...
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A new species of Lobelia is described from Rio Muni and Congo- Brazzaville. The discriminant characters with the nearby Lobelia hartlaubii Buchenau are given: pedicel shorter, less than 1 mm, and hypanthium narrower, cylindrical and not obconical.
Article
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The impact of bush fire on the dynamic of vegetation in Bassila forest was studied. The results show reforestation in the plot protected from bush fire and decrease of forest species in the plot affected by late fire. In the plot affected by early fire, most species present at the beginning of the study had a normal development. Late fire allowed a...
Article
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The stations and ecological indicatory value of the plant community Landolphio—Lecaniodiscetum cupanioidis have been studied in the natural undergrowth of teak plantations of Djigbé forest in south Benin. The main results show that the association occures on reddish non hydromorphic clay soils slightly acidic to neutral (pH 6 to 7,3). Its soils are...
Article
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After several investigations on the savanna and forest of Ngotto (Central African Republic), we propose a phytogeographical interpretation of our data on the systematic (level family), the biological forms, the dispersion of diaspores and phytogeographical elements spectra. These spectra are given regarding both formation type (savanna, forest) to...
Article
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In Northern Benin, inselberg called Sobakpérou of meridional Sudaneze domain was studied. The objective of this study, concerning only on single site and carried according to the altitudinal gradient, is to describe the plant communities using the phytosociological method. Seven types of plant communities belonging to four plant formations are desc...
Article
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The Bipindi-Akom II region in South-Cameroon belongs to the Biafran atlantic district of the Guineo-congolian domain of dense humid evergreen forests. Inside this vegetation unit, Garcinia lucida is a remarkable understorey gregarious species, growing in low-lying ground and on slope of some hills. Four localities in which this species occurs have...
Article
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Two species of the genus Merremia, both native of tropical America, are cited for the first time for the flora of Benin: M. cissoides (Lam.) Hallier f. and M. quinquefolia (L.) Hallier f. A key to the nine species actually known from Benin is given. For the genus Merremia in Benin, these new introductions are the only species characterized by compo...
Article
This work constitutes a first study on the flora and the vegetation of the intra—forest clearings on hydromorphic soils of the Gabon. It analyzes the floral composition, brings to light the main plant communities and the species which characterize them. An analysis of environmental structural factors is then realized to characterize these communiti...
Article
A study aiming the establishment area—species relationship considering the age of the fallow has been led in the perimeter of the natural forest reserve of Kigwena (Burundi). According to the systematic inventory of all vegetal species present in three classes of fallows (0–2 years, 3–5 years and more than 5 years), equations of tendency curves obt...
Article
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We report results from a phytosociological investigation of the vegetation of three inselbergs from continental Equatorial Guinea. Ten vegetation units belonging to five plant formations are described: grass-land, herbaceous fringe, shrubby fringe, forest fringe and saxicolous forest. One of the most striking plant communities on inselbergs are spe...
Article
Background and aims - Sericostachys scandens (Amaranthaceae), an indigenous liana in Kahuzi-Biega National Park (KBNP, D.R.Congo), has been spreading strongly in montane forests for about ten years. We have tried to assess the consequences of this expansion on forest regeneration. Methods - We carried out an inventory of tree individuals (≤ 1 m in...
Article
In order to analyze the influence of the spatial structure of the ecological functioning of forest ecosystems, a study on the spatial distribution of natural regeneration and coexistence of the main tree species was conducted in Bururi Forest Nature Reserve in Burundi. This protected area is the southernmost part of the Congo-Nile ridge forest syst...
Article
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Background and aims - Agricultural activities and livestock pasture constitute the main human pressures on the Fina reserve in Mali. Their impacts are amplified by the bushfires and climate variations. Their impacts are amplified by bushfires and climate variability. These modifications seem to be generalized and even concern protected areas. In th...
Article
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Dans le but d'élaborer des recommandations pour une gestion durable des principales ressources en bois-énergie du Bassin arachidier sénégalais, différents diamètres et hauteurs de coupe ont été testés sur Guiera senegalensis J.F. Gmel et Combretum glutinosum Perr. Le dispositif expérimental est adapté à la période habituelle d'exploitation (mois de...
Article
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In the mountain forests of the Kahuzi-Biega National Park (KBNP), in the Democratic Republic of Congo, where Sericostachys scandens, a woody climbing plant in the Amaranthaceae family, is expanding, trees appear to be negatively affected by this liana. In order to contribute to the understanding of the links between the expansion of the liana and t...
Article
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Sericostachys scandens is a monocarpic and heliophilous liana, native in tropical African forests. In the montane forests of the Kahuzi-Biega National Park (KBNP) (East of DR Congo), it has been expanding very strongly for a decade, and is currently considered as having negative impacts on biodiversity conservation. In this paper, we test if S. sca...
Article
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La valorisation des produits forestiers locaux est entravée faute de connaissances précises sur leur potentiel et de pouvoir évaluer leur impact sur l'économie nationale. En outre, le manque de connaissances sur la disponibilité des produits des arbres agroforestiers (Paaf) au sein de leur biotope ne permet pas d'élaborer une planification fiable p...
Article
The development of local forest products is hampered by insufficient knowledge about their potential and inadequate assessments of their impact on the national economy. Furthermore, lack of knowledge on the availability of agroforestry tree products (AFTPs) in their biotope prevents effective planning for sustainable management of non-timber forest...
Article
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The Ruvubu National Park, the biggest protected area and biodiversity refuge of the country, is comparatively less studied than western Burundi near Bujumbura, the capital. This article reports the results of a botanical inventory of the vascular plants from the protected area, evidences species newly encountered and establishes a comparison of the...
Chapter
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The W Regional Park covers adjacent areas in Benin, Burkina Faso and Niger with Niger River as its natural border in the Northern part. The aim of this study was to describe the diversity and dynamics of plant communities in this park. For that, Floristic and phytoecological data were collected using the phytosociological method of Braun-Blanquet (...
Article
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La forêt marécageuse de Lokoli est située à Zogbodomey au Sud-Bénin et ses Produits Forestiers Non Ligneux (PFNL) constituent des sources de revenus pour les populations riveraines. L’objectif de l'étude est de déterminer l'influence de l'exploitation des PFNL sur les communautés végétales. Sur la base de relevés phytosociologiques et des enquêtes...
Article
Although many African cities are confronted to an important population growth, there are almost no studies describing their vegetation and how it is affected by the urbanization process. We present here the description of the spontaneous vegetation of the capital city of Burundi, Bujumbura, through the analysis of 437 vegetation plots. Ruderal plan...
Article
Les études relatives à la flore et à la végétation des aires protégées du Burundi et particulièrement du Parc National de la Ruvubu, la plus grande aire protégée du pays, sont encore fragmentaires. Cette étude se fixe comme objectifs d’individualiser, définir et réaliser une classification syntaxonomique des groupements végétaux de cette aire proté...
Chapter
Rattan is an important non-wood forest product in the economy of Democratic Republic of Congo (DR Congo) and in the subsistence of populations in the Congo Basin. This paper presents preliminary results of a survey conducted with rattan stakeholders in Kisangani and the Yoko Forest Reserve (YFR) neighbourhood, in the Orientale Province, DR Congo. T...
Article
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Résumé Dans la forêt marécageuse de Lokoli, la forêt primaire inondée à Alstonia congensis Engl. et Xylopia rubescens Oliv. est le groupement qui correspond à la végétation climacique de cet écosystème unique au Bénin et en Afrique de l’Ouest. Pour le caractériser, des relevés phytosociologiques ont été effectués ; des données de régénération ont é...
Article
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Des recherches ont été menées sur la biodiversité des jachères situées dans la périphérie des aires protégées du Burundi. Les données relatives aux traits biologiques (forme de vie, types de diaspores et types foliaires) ont été collectées sur divers compartiments reflétant les facteurs spatial et temporel. Les résultats montrent des variations sig...