Gérard Imani

The Congo Basin, spanning over 3.7 million km ² across Central Africa, plays a critical role in regulating global climate, sustaining biodiversity, and supporting regional livelihoods. We explore the ecological functions of the Congo Basin ecosystems, emphasizing their role in the carbon cycle. We synthesize current knowledge on biogeochemical processes, carbon stocks, species interactions, and biodiversity patterns, while highlighting key data gaps and research needs. The region’s forests, soils, wetlands, and aquatic systems together form one of the world’s most significant carbon sinks, with unique characteristics, including high megafaunal density, extensive peatlands, and relatively low deforestation rates, shaping its contributions to carbon sequestration and climate regulation. We detail carbon cycle dynamics across lowland, montane, flooded, and savanna ecosystems and underscore the vast belowground carbon storage in the Cuvette Centrale peatlands. Patterns of alpha and beta tree species diversity affect ecosystem function and resilience, with plant functional traits playing a key role in nutrient cycling and productivity. Species such as forest elephants influence forest structure and carbon storage through seed dispersal and disturbance. Moreover, strong land-atmosphere feedbacks mean that evapotranspiration from the Congo Basin’s tropical forests plays a key role in shaping regional rainfall patterns. Land use and climate change pose growing threats to these functions, potentially triggering regime shifts and biodiversity loss. Ultimately, the Congo Basin remains underrepresented in ecological research and monitoring despite its global importance. Enhanced field-based and remote sensing efforts are urgently needed to inform integrated conservation and climate change mitigation strategies that account for both carbon dynamics and biodiversity.

The Congo Basin, spanning over 3.7 million km ² across Central Africa, plays a critical role in regulating global climate, sustaining biodiversity, and supporting regional livelihoods. We explore the ecological functions of the Congo Basin ecosystems, emphasizing their role in the carbon cycle. We synthesize current knowledge on biogeochemical processes, carbon stocks, species interactions, and biodiversity patterns, while highlighting key data gaps and research needs. The region’s forests, soils, wetlands, and aquatic systems together form one of the world’s most significant carbon sinks, with unique characteristics, including high megafaunal density, extensive peatlands, and relatively low deforestation rates, shaping its contributions to carbon sequestration and climate regulation. We detail carbon cycle dynamics across lowland, montane, flooded, and savanna ecosystems and underscore the vast belowground carbon storage in the Cuvette Centrale peatlands. Patterns of alpha and beta tree species diversity affect ecosystem function and resilience, with plant functional traits playing a key role in nutrient cycling and productivity. Species such as forest elephants influence forest structure and carbon storage through seed dispersal and disturbance. Moreover, strong land-atmosphere feedbacks mean that evapotranspiration from the Congo Basin’s tropical forests plays a key role in shaping regional rainfall patterns. Land use and climate change pose growing threats to these functions, potentially triggering regime shifts and biodiversity loss. Ultimately, the Congo Basin remains underrepresented in ecological research and monitoring despite its global importance. Enhanced field-based and remote sensing efforts are urgently needed to inform integrated conservation and climate change mitigation strategies that account for both carbon dynamics and biodiversity.

Lowland and highland forests of the Kahuzi‐Biega National Park (KBNP) in the eastern Democratic Republic of Congo were studied to understand their ecology. The lowland ranges from 810 to 1230 m asl and the highland from 1935 to 2760 m asl. Ten 1‐ha nested plots were established in each area; trees with ≥ 10 cm of dbh were inventoried for the tree layer. In each area, 10 0.1‐ha and 10 0.01‐ha subplots were established for the shrub and herbaceous layers, respectively. In the tree layer, plant diversity, species richness and species pool size differed at different altitudes; the lowland is more diverse and richer (140 vs. 88 species). In the shrub layer, only the Fisher‐alpha index differed, showing high diversity in the lowland (14 ± 7.1 vs. 8.9 ± 2.9). In the herbaceous layer, the highland had a higher number of species (78 vs. 50). Twenty‐eight, twenty‐nine and five species were common to both highland and lowland in the tree, shrub and herbaceous layers, respectively. Height and dbh classes and basal area did not differ, but the importance value indexes of species and families did. These results show that the lowland and highland forests of KBNP differ in the three layers, suggesting tailored management plans.

Despite increasing interest in including indigenous and local people in forest restoration initiatives, their views on which species are most useful, or reasons behind not planting native tree species are often ignored. Focused on south-western Rwanda, this study addressed these knowledge gaps. We carried out 12 focus group discussions with village elders to determine the following: main benefits provided by native forests, the native species they prefer for different uses, and the main barriers to species’ cultivation. Then, considering other key information from the literature, we performed a ranking exercise to determine which native species had the greatest potential for large-scale tree planting initiatives. Our results show that native forests provide 17 benefits to local communities, some of which cannot be replaced by plantations with exotic species. Among the 26 tree species identified as most useful for timber, firewood, medicine and fodder, ten were ranked as with the greatest potential for restoration initiatives. Of these, two had not been included in recent experimental plantations using native species in Rwanda, and none were considered among the priority species for domestication in Africa. Overall, our study highlights the need to better connect the ecological and social dimension of forest reforestation initiatives in multiple contexts.

People living in conflict-affected areas are particularly vulnerable to climate-related impacts. However, few comparative studies have examined differences in adaptation practices across different conflict-affected mountain areas in Africa. This study focuses on 2 mountain areas, the Bamboutos Mountains (western Cameroon, affected by sectarian conflict) and the Itombwe Mountains (eastern Democratic Republic of the Congo, affected by political instability). Semistructured interviews were conducted with 282 smallholder farmers living in these 2 mountainous areas. Farmers in both areas reported climatic changes and impacts on crops, animals, and human health. Some adaptation strategies were used across sites (eg increasing use of improved seeds and changing planting dates), but some differed (eg using inputs) in relation to differences in impacts observed, conflict characteristics, and farmers' cultural backgrounds. For example, in the Itombwe Mountains, herding was preferred over crop production (as cows could be moved when insecurity increased), whereas in the Bamboutos Mountains, crop production was preferred over rearing large animals (as these could be easily stolen by the separatists). We discuss the perceived major barriers to adaptation and their implications.

Forests are a large reservoir of biodiversity on which riparian populations frequently rely. Non-timber forest products (NTFPs) are an important source of income for millions of people living in forest-adjacent communities. This study aims at characterizing the types and uses of NTFPs in order to determine whether their exploitation in the eastern Democratic Republic of the Congo is sustainable. Interviews and direct observation were carried out with NTFP stakeholders (harvesters, sellers, and consumers) in Kalonge, near the Kahuzi-Biega National Park. The results showed that 40 NTFPs of plant origin and 10 NTFPs of animal origin are commonly exploited and used in food and traditional medicine. The most common NTFP harvesting techniques are debarking, picking, digging up, felling, and wine extraction, which are all tailored to the plant part. A significant relationship (p-value< 0.001) has been established between the types of NTFPs used and harvesting methods as well as between the types of NTFPs used and organs retrieved. NTFP products are mainly obtained from the natural forest KBNP but also in the woodland, trees grown outside of forest or through domestication. Their abundance, however, is hampered by the extraction of wood for charcoal, energy, and timber, as well as agricultural expansion. The supply of NTFPs is determined by the market demand for the products, the nature of the product, and the ease of disposal. The NTFPs value chain in Kalonge is important to the local economy, however exploitation of NTFP products remains uncontrolled and should be well managed to ensure sustainability.

The latitudinal diversity gradient (LDG) is one of the most recognized global patterns of species richness exhibited across a wide range of taxa. Numerous hypotheses have been proposed in the past two centuries to explain LDG, but rigorous tests of the drivers of LDGs have been limited by a lack of high-quality global species richness data. Here we produce a high-resolution (0.025° × 0.025°) map of local tree species richness using a global forest inventory database with individual tree information and local biophysical characteristics from ~1.3 million sample plots. We then quantify drivers of local tree species richness patterns across latitudes. Generally, annual mean temperature was a dominant predictor of tree species richness, which is most consistent with the metabolic theory of biodiversity (MTB). However, MTB underestimated LDG in the tropics, where high species richness was also moderated by topographic, soil and anthropogenic factors operating at local scales. Given that local landscape variables operate synergistically with bioclimatic factors in shaping the global LDG pattern, we suggest that MTB be extended to account for co-limitation by subordinate drivers.