Diversité et distribution d'abondances des plantes d'un écosystème protégé dans un paysage anthropisé: cas de la Réserve Naturelle Forestière de Bururi, Burundi

info:eu-repo/semantics/publishe

Diversité et distribution d'abondances des plantes d'un écosystème protégé dans un paysage anthropisé: cas de la Réserve Naturelle Forestière de Bururi, Burundi

Plant Diversity and Abundance Distribution of a Protected Ecosystem in an Anthropogenic Landscape: the Case of the Bururi Natural Forest Reserve of, Burundi. A study on plant species diversity and abundance distribution has been conducted in the Bururi Natural Forest Reserve (BNFR) in Burundi in order to improve species conservation. The BNFR is an ecosystem embedded in an anthropogenic matrix, close to Bururi city and to agricultural lands. It is a forest patch resulting from the fragmentation of a larger forest that once occupied the entire Congo- Nile Crest. This study tested the hypothesis according to which the plant species abundance distribution in conserved forests corresponds to a log normal distribution, indicating that species are regularly distributed in the ecosystem. This distribution model is generally observed in stable ecosystems in which inter-specific competition is considered less important. The observed abundance distribution of the plant species was therefore compared to a log normal, a log series and a broken stick distribution model. Six of the plant species recorded in this study are considered threatened in Burundi. The observed plant species abundance distribution was found similar to the log series model which suggests the impact of disturbance on the abundance distribution despite the status of the BNFR of protected ecosystem in an anthropogenic landscape

Impact de la structure spatiale de Strombosia scheffleri Engl. et Xymalos monospora (Harv.) Baill sur la régénération naturelle et la coexistence des espèces arborescentes dans la Réserve Naturelle Forestière de Bururi, Burundi

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Impact de la structure spatiale de Strombosia scheffleri Engl. et Xymalos monospora (Harv.) Baill sur la régénération naturelle et la coexistence des espèces arborescentes dans la Réserve Naturelle Forestière de Bururi, Burundi

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 system. The study tests the hypothesis that the aggregated spatial structure of a tree species would have an impact on natural regeneration and the coexistence of other tree species in the same habitat. Two methods were used to determine the type of spatial distribution of tree species: one based on the distance to the nearest neighbor and the second on change in the number of individuals of the species in the sample plots. Natural regeneration was evaluated on the basis of the distribution of their diameters. Analysis of the spatial distribution showed that Strombosia scheffleri and Xymalos monospora are characterized by a spatial distribution of aggregate. Then, the study was highlighted the negative impact of the aggregate distribution of S. scheffleri and X. monospora on natural regeneration of Entandrophragma excelsum and Prunus africana, two endangered species in Burundi. Thus, the local dominance of a tree species can reduce the diversity as stipulated in the escape hypothesis.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

The contribution of internally displaced persons camps to the landscape dynamics in southern and southeastern of Burundi

Nowadays, tropical zones are characterized by a catastrophic decline of forest ecosystems areas which play however an important role in climate regulation and biodiversity conservation. There are numerous and complex causes of deforestation. Even if agriculture is one of the main causes of deforestation in most tropical regions, sub-Saharan Africa had exceptional influences related to social conflicts. In Burundi, socio-political instability which occurred in 1993 also led to massive waves of displaced people, essentially farmers. The present study aims to analyze the land cover spatiotemporal dynamics and focuses particularly on the influence of this population forced to migrate. The study combines satellite images analysis with field observations to analyze land cover dynamic in the camp's surrounding zone. The negative impact of the socio-political instability has been demonstrated by vegetation anthropization decrease when the distance from the camps increases. The greatest anthropogenic pressure which is observed during the period that followed the outbreak of the socio-political instability also confirms this negative impact. The rehabilitation of those deforested or degraded zones is therefore essential. © 2018 Agri-Overseas

La dynamique spatiale de la forêt située dans la réserve naturelle forestière de Bururi, Burundi

The Forest Spatial Dynamic in the Bururi Forest Nature Reserve, Burundi. The studied forest is a protected area located in Southern Burundi, close to Bururi city and to agricultural villages. The effective protection of this forest started in 1980 but the protected area delimitation occurred in 2000. The forest spatial dynamic is analyzed to assess the effectiveness of this protection status. The study combines six Landsat multispectral satellite images analysis with field observations. Forest area and perimeter analysis highlights its dynamic in two phases: the first one is mainly characterised by deforestation and savannah development around agricultural lands but also by forest regrowth processes between 1986 and 2001. The second phase (2001-2011) of the forest dynamic is characterized by the increase of its surface and perimeter following the transformation of savannah zones. The anthropogenic effect limitation linked to the protected area delimitation, agricultural activities disturbance during socio-political instability period and to the increasing number of forest-rangers, would have influenced the surface and perimeter gain between 2001 and 2011. Local population implication in forest protection could further limit human pressure and promote degraded zones regeneration. Thus, agropastoral practices innovation in neighboring villages of the protected zone could contribute to limit these anthropogenic disturbances

The forest spatial dynamics in the Bururi forest nature reserve, Burundi [La dynamique spatiale de la foret situee dans la reserve naturelle forestiere de Bururi au Burundi]

The studied forest is a protected area located in Southern Burundi, close to Bururi city and to agricultural villages. The effective protection of this forest started in 1980 but the protected area delimitation occurred in 2000. The forest spatial dynamic is analyzed to assess the effectiveness of this protection status. The study combines six Landsat multispectral satellite images analysis with field observations. Forest area and perimeter analysis highlights its dynamic in two phases: the first one is mainly characterised by deforestation and savannah development around agricultural lands but also by forest regrowth processes between 1986 and 2001. The second phase (2001-2011) of the forest dynamic is characterized by the increase of its surface and perimeter following the transformation of savannah zones. The anthropogenic effect limitation linked to the protected area delimitation, agricultural activities disturbance during socio-political instability period and to the increasing number of forest-rangers, would have influenced the surface and perimeter gain between 2001 and 2011. Local population implication in forest protection could further limit human pressure and promote degraded zones regeneration. Thus, agropastoral practices innovation in neighboring villages of the protected zone could contribute to limit these anthropogenic disturbances