Climate variability influences plant growth. With the variation in atmospheric CO2 concentration leading to global warming, it is urgent to monitor the performance of plant ecosystems for optimal carbon sequestration. Net primary productivity (NPP) is the perfect measurement tool as it measures the net carbon flux between the atmosphere and green plants and the factors that affect it. This study applied remote sensing techniques, specifically one of the radiation use efficiency models; the CASA model (Carnegie-Ames-Stanford approach) to assess the spatio-temporal dy-namics of NPP in Togo from 1987 to 2022 and the climatic parameters that influence it. The annual average NPP over the 36 years of the study is 4565.31 Kg C ha⁻¹. Variability is observed over the years with extremes in 2017 (6312.26 Kg C ha⁻¹) and 1996 (3394.29 Kg C ha⁻¹). Natural formations identified as high-production areas saw their productivity increase between 2000 and 2022. The interaction between climate change and land use changes negatively influences the variation of Total Production (PT) between 2000 and 2022, while individually, these parameters positively influence the variation of NPP (58.28% and 188.63%). The correlation result is positive and higher between NPP and light use efficiency (LUE) (r² = 0.75). Actual evapotranspiration also shows a positive correlation with NPP (r² = 0.43). A positive but weak correlation is observed between NPP and precipitation, potential evapotranspiration (r² = 0.20; 0.10 respectively). Temperatures have almost no correlation with NPP (r² = 0.5). Climatic parameters as a whole under the LUE banner influence NPP more. This study helps understand ecosystem performance in the context of To-go's commitments to reduce greenhouse gas emissions and combat climate change.

Climate variability significantly impacts plant growth, making it crucial to monitor ecosystem performance for optimal carbon sequestration, especially in the context of rising atmospheric CO2 levels. Net Primary Productivity (NPP), which measures the net carbon flux between the atmosphere and plants, serves as a key indicator. This study uses the CASA (Carnegie–Ames–Stanford Approach) model, a radiation use efficiency method, to assess the spatio-temporal dynamics of NPP in Togo from 1987 to 2022 and its climatic drivers. The average annual NPP over 36 years is 4565.31 Kg C ha−1, with notable extremes in 2017 (6312.26 Kg C ha−1) and 1996 (3394.29 Kg C ha−1). Productivity in natural formations increased between 2000 and 2022. While climate change and land use negatively affect Total Production (PT) from 2000 to 2022, they individually enhance NPP variation (58.28% and 188.63%, respectively). NPP shows a strong positive correlation with light use efficiency (r2 = 0.75) and a moderate one with actual evapotranspiration (r2 = 0.43). Precipitation and potential evapotranspiration have weaker correlations (r2 = 0.20; 0.10), and temperature shows almost none (r2 = 0.05). These findings contribute to understanding ecosystem performance, supporting Togo’s climate commitments.

This bibliographic analysis focused on various methods for estimating net primary productivity, vegetation indices and their various applications, as well as vulnerability assessment and management strategies for protected areas. To do this, a bibliography on the different topics collected using search engines Scopus, Science Direct, ResearchGate, and Google Scholar via the Publish or Perish portal was analyzed. Of the 1128 scientific papers on the selected topic after refining the database, 978 were journal articles, 59 were books, 52 were reports, 20 were conference proceedings, and 19 were theses. These documents detail numerous methods for estimating net primary productivity, a key parameter for assessing ecosystem performance. Methods using remote sensing data, especially vegetation indices, appear to be the easiest, least costly, and least labor-intensive today, ensuring reliable results. These innovative methods are best suited for assessing fragile ecosystems. This is the case for protected areas which have been facing the combined effects of anthropogenic actions and climate change in recent years. Considering the challenges posed by the management of Togolese protected areas, particularly since the socio-political disturbances of the 1990s, it is urgent to assess the health status of these specific ecosystems, focusing on their performance.

Contexte et justification : Les écosystèmes de la Forêt classée de la fosse de Doungh (FCFD) au Togo ont subi une dégradation très alarmante menaçant la survie de cet écosystème vitale. Disposer des connaissances sur diversité floristique et la structure des formations végétales contribuerait à la mise en œuvre d’un plan de gestion et de restauration de cette forêt classée. But et objectifs : Cette étude est une contribution à la gestion et à la restauration des écosystèmes forestiers de la FCFD, dans la Préfecture de Tandjouaré au Togo. Elle a évalué la diversité floristique, l’état de conservation des espèces ligneuses et la structure démographique des formations ligneuses. Méthodologie Les données physiques (inventaires floristiques, forestiers et écologiques) ont été collectées au sein de 83 placettes rectangulaires de 50 m x 20 m. La caractérisation floristique s’est basée sur les indices de diversité de Shannon, l’équitabilité de Piélou et l’indice de valeur d’importance des espèces. L’analyse structurale des formations végétales est faite par calcul arithmétique des caractéristiques forestières quantitatives et la structure en diamètre et hauteur des ligneux. Résultats : Au total, 204 espèces réparties en 140 genres et appartenant à 52 familles ont été inventoriées dans 83 placettes de forme rectangulaire de 50 m x 20 m. Les relevés ont été discriminés en 5 sous-groupes : des savanes arborées/arbustives, des champs/savanes arborées, les ripisylves, les savanes arborées et les parcs agroforestiers. On note la prédominance des individus jeunes avec de faibles diamètres et des hauteurs moyennes. La régénération est dominée par les souches (54,62%) témoignant de l’impact anthropique assez important dans cette aire protégée. Trois actions anthropiques majeures : l’agriculture (39,88 %), le feu de végétation (22,67 %) et la coupe de bois (23,10 %) respectivement favorisent l’amenuisement des ressources dans la forêt.

Affem Boussou community forest (AFC) abounds in important biological resources. This study, which contributes to its better management, examines the spatiotemporal dynamics of the vegetation and its ecological and structural characteristics to propose a zoning plan for said forest. The analysis of the spatiotemporal dynamics of land use in the AFC from Google Earth images of 2015, 2018, and 2021 revealed a regressive trend of formations: crops and fallows (−33.98%), dense dry forests (−7.92%), gallery forests (−3.46%), plantations (−100%), grassy savannahs, and meadows (−18.84%), except for tree/shrub savannahs (484.23%). The floristic inventory identified 163 species divided into 129 genera and 55 families. Fabaceae (14.02%), and Combretaceae (10.55%) are the most represented families. Anogeissus leiocarpa (5.19%) and Vitellaria paradoxa (4.72%) are the most frequent species. We note the dominance of individuals of small diameters. The regeneration potential of the AFC is 64 feet/ha due to 21 feet/ha of suckers, 29 feet/ha of seedlings, and 14 feet/ha of shoots. As a zoning plan, the AFC was subdivided into four zones: the agroforestry zone (18.80%), the sustainable production forest zone (42.22%), the buffer zone (11%), and the biological conservation zone (28%). These results constitute a scientific basis for testing ecological indicators of the sustainable management of community forests in Togo.

La phytoremédiation est un processus d’utilisation des plantes à travers l’extraction, la stabilisation, la dégradation et la volatilisation pour dépolluer les sols, l'eau et l'air contaminés par des substances toxiques, polluantes ou des métaux lourds. Les plantes phytoremédiatrices restent à ce jour un moyen efficace pour lutter contre la pollution de l’eau, du sol et de l’air. L’objectif général du présent travail est de contribuer à l’épuration des eaux à travers les plantes phytoremédiatrices. L’étude s’est consacrée au potentiel de phytoremédiation de Eichhornia crassipes (Mart.) Solms-Laub reconnue comme l’espèce la plus accumulatrice de polluants dans la zone d’étude, dans un dispositif expérimental en mode discontinu. Ce travail préalable a consisté en une étude bibliographique sur les espèces phytoremédiatrices et d’une étude expérimentale de la cinétique de la phytoremédiation de la jacinthe d’eau. Les paramètres physico-chimiques pris en compte sont le pH, la conductivité, l’orthophosphate, les nitrates, la Demande Biologique en Oxygène (DBO), et la Demande Chimique en Oxygène (DCO). Les valeurs du pH, l’orthophosphate, la DBO et la DCO ont diminué respectivement de 3,20 %; de 68 %; de 97 % et de 85 % au 24ème jour mais la concentration des nitrates a augmenté de 0,8 mg NO3-/l à 65,5 mgNO3-/l. Cette augmentation des nitrates est due à la nitrification de l’azote ammoniacal en nitrite. Mots clés: Plantes phytoremédiatrices, assainissement, Eichhornia crassipes, cinétique, eaux usées

Tropical peri-urban ecosystems are essential for the urban population’s well-being through the goods and services they provide. Unfortunately, these ecosystems are subjected to anthropogenic pressures for various reasons. This study aims to assess the diversity and structure of the peri-urban ecosystems that provide the most edible insects in Kinshasa. A total of 360 people were interviewed to identify the two insect species most frequently consumed. The tree inventory was carried out in 50 plots (2500 m2 each), of which 25 were in Acacia plantations, 10 were planted Milletia forests, and 15 were natural Millettia forests. The diameters of each tree, dbh ≥ 10 cm, were measured. Principal component analysis (PCA) was used to distinguish the forest communities. Diversity indices were used to assess floristic variability and structural parameters were used to characterize forest stands. Two insects were identified as being the most commonly consumed in Kinshasa: Gonimbrasia jamesoni (28%) and Cirina forda (27%), found the in Acacia plantation, and in the planted Milletia forests and natural Milletti forest, respectively. The results indicate floristic (higher in the Acacia plantation) and structural variability between stands. The structure of the stands indicates good news for all forests, except the planted forest. The high frequency/dominance of A. auriculiformis and M. laurentii in the peri-urban ecosystems of Kinshasa would therefore be optimal conditions (under natural conditions) for good production of these two caterpillar species.