Climate change and hunter-gatherers in montane eastern DR Congo

Mountain environments experience more rapid changes in temperature than lower elevations. However, little is known about the climatic changes already observed in African mountains, or the adaptation strategies used by hunter-gatherer communities. Semi-structured interviews were administered to 100 Twa hunter-gatherers living around Mt Kahuzi in eastern Democratic Republic of the Congo (DR Congo). We also organized 10 focus-group discussions with Tembo farmers living in the same area and we gathered historical from Kamembe meteorological station. Twa respondents perceived reduced rainfall and fog, and increased temperatures. They also reported reduced crop yields and abundance of forest products (caterpillars, mushrooms, honey). Tembo perceptions of climatic changes and impacts agreed with the Twa. Meteorological data available shows reduced rainfall and increased temperatures – but there are no records on fog. Despite being aware of climatic changes and impacts, Twa are not using any adaptation strategy, while Tembo farmers are using some (as they own land for farming or animal rearing, and are more business minded). For the Twa, their socioeconomic condition create high sensitivity to climate change and constrain adaptive capacity. To help the Twa, we recommend the use of “science with society” (SWS) participatory approach

Investigating above ground biomass in old-growth and secondary montane forests of the Cameroon Highlands

Tropical montane forests can store and sequester substantial amounts of carbon in above ground biomass (AGB), but variations in this storage related to location or degradation have not been quantified in the Cameroon Highlands. We established 25 permanent plots (20m x 40m) and sampled all trees ≥ 10 cm diameter following standard RAINFOR protocols. We estimated AGB, and investigated variations related to taxonomic and structural forest attributes, including the height-diameter allometry in five forest types (four old-growth dominated by different species and one secondary forest). Secondary forests had significantly lower AGB than old-growth forests (49.4 ± 2.5 vs > 476.3 ± 168.7 Mg ha-1, respectively), mostly related to lower basal area and tree height. Significant differences in species composition but not in forest structure or AGB were found between the four types of old-growth forests studied, located at different altitudes and mountains. We discuss the importance of these montane forests for carbon storage and, considering their high diversity and current threats, their potential for carbon finance mechanisms related to both avoided deforestation and forest restoration

The importance of livelihood strategy and ethnicity in forest ecosystem services’ perceptions by local communities in north-western Cameroon

Human culture has an important influence on how forests are utilised, yet its influence on ecosystem service (ES) use and valuation remains underexplored. We address this gap by investigating how livelihood strategy and ethnicity affect local peoples’ perceptions of forest ES in Cameroon. Data were collected through 20 focus-group discussions in villages of farmers (Oku and Banso) and pastoralists (Fulani) in two mountains. Pastoralists identified fewer ES than farmers, and used some ES differently (e.g. wildlife was only valued for aesthetics instead of as food). Some differences were also observed between farmer groups (e.g. identity link with the forest unique to Oku farmers). While water availability was perceived as the most important forest ES for all groups, the second most important was fodder for pastoralists and medicine resources for farmers. Pastoralists also identified fewer useful forest species, most likely related to their origin in the lowlands. Our findings help highlight trade-offs in important ES for different groups (fodder vs. medicine resources), and in access to certain ES (e.g. Fulani pastoralists’ unequitable access to tourism and forest income). We show that locals dependent on provisioning ES are not a homogenous group and that the wider socio-cultural context has to be taken into account for conservation and development projects to be successful

Special Issue Editorial : Mountains under Pressure

Mountains are highly significant regions in the context of climate change and sustainable development; they are situated at the intersection of accelerated climate warming, changes in moisture regime and support a large population that depends on mountains for their livelihoods, either directly or indirectl

Sensitivity of a tropical montane cloud forest to climate change, present, past and future: Mt. Marsabit, N. Kenya

During the Last Glacial Maximum (LGM) lowland forests contracted throughout the tropics but, by contrast, many montane forest taxa moved to lower elevations. These taxa are often found in cloud forests, which are globally important ecosystems that depend on the capture of atmospheric water from fog drifting through the canopy, here referred to as occult precipitation. Understanding the response of tropical montane taxa to climate variations is limited by a lack of modern data on fog capture; whereas palaeoecological data only provide indirect evidence for its importance. Hence, the response of vegetation to fog capture is not considered in palaeo-estimates of precipitation. We develop a method that uses satellite Normalized Difference Vegetation Index (NDVI) data to estimate the annual amount of occult precipitation and investigate the sensitivity of a cloud forest to past and future changes in both rainfall and occult precipitation. We apply this method using satellite and meteorological data from 1982 to 2015 collected at Mt Marsabit, which is located in northern Kenya (2.34∘ N, 37.97∘ E, summit 1707 m a.s.l.). Mt Marsabit has a sub-humid tropical montane cloud forest at its summit that is excessively green for the amount of rain it receives. We estimate the annual amount of occult precipitation for current conditions at about 900 mm y−1 which is more than the average annual rainfall of 700 mm y−1. This is consistent with the observation that, for the wider Marsabit area, interannual variations in NDVI are more closely linked to changes in cloud-base height () than to changes in rainfall (). We investigate the sensitivity of forest extent to past and future changes; for the LGM we estimate that cloud-base height decreased by 500 m in response to a 4 ∘C cooling and that this caused a 20%–100% increase in forest area despite a 30% decrease in rainfall, a 22% decrease in atmospheric humidity and a substantial reduction of atmospheric CO2 levels (values representative for mountains in Kenya during the LGM). An expected increase of 250 m in the cloud-base height associated with a future 2 ∘C global warming is likely to reduce forest extent by 50%–100%. Our results indicate that the satellite vegetation record is useful to estimate modern hydrological inputs into drier cloud forests (up to 2000 mm y−1) and that this information can be used to estimate the contribution of occult precipitation to altitudinal displacements of tropical montane cloud-forest species during the Quaternary

Local perceptions of climate change and adaptation responses from two mountain regions in Tanzania

Authors acknowledge funding from the UK Research and Innovation’s Global Challenges Research Fund (UKRI GCRF) through the Development Corridors Partnership project (project number: ES/P011500/1). This work was also supported through the African Women in Climate Change Science Fellowship of the African Institute of Mathematical Sciences and the Next Einstein Forum, and the Climate Research for Development (CR4D) Postdoctoral Fellowship CR4D-19-21 implemented by the African Academy of Sciences (AAS) in partnership with the United Kingdom’s Department for International Development (DfID) Weather and Climate Information Services for Africa (WISER) programme and the African Climate Policy Center (ACPC) of the United Nations Economic Commission for Africa (UNECA).Mountain environments and communities are disproportionately impacted by climate change. Changes in temperature are greater than at lower elevations, which affect the height of the cloud base and local rainfall patterns. While our knowledge of the biophysical nature of climate change in East Africa has increased in the past few years, research on Indigenous farmers’ perceptions and adaptation responses is still lacking, particularly in mountains regions. Semi-structured interviews were administered to 300 farmers on Mount Kilimanjaro (n = 150) and the Udzungwa Mountains (n = 150) in Tanzania across gender and wealth groups. Respondents in both mountains reported not only changes in rainfall and temperature, corresponding with meteorological data, but also a greater incidence of fog, wind, frost, and hailstorms—with impacts on decreased crop yields and increased outbreaks of pests. The most common adaptation strategies used were improved crop varieties and inputs. Wealthier households diversified into horticulture or animal rearing, while poorer households of Hehe ethnicity diversified to labour and selling firewood. Despite being climate change literate and having access to radios, most respondents used Indigenous knowledge to decide on planting dates. Our findings highlight how context and culture are important when designing adaptation options and argue for greater involvement of local stakeholders in adaptation planning using a science-with-society approach. Place-based results offer generalisable insights that have application for other mountains in the Global South.Publisher PDFPeer reviewe

Drivers of aboveground wood production in a lowland tropical forest of West Africa:teasing apart the roles of tree density, tree diversity, soil phosphorus, and historical logging

This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by Wiley.1. Tropical forests currently play a key role in regulating the terrestrial carbon cycle and abating climate change by storing carbon in wood. However, there remains considerable uncertainty as to whether tropical forests will continue to act as carbon sinks in the face of increased pressure from expanding human activities. Consequently, understanding what drives productivity in tropical forests is critical. 2. We used permanent forest plot data from the Gola Rainforest National Park (Sierra Leone) – one of the largest tracts of intact tropical moist forest in West Africa – to explore how (i) stand basal area and tree diversity, (ii) past disturbance associated with past logging and (iii) underlying soil nutrient gradients interact to determine rates of aboveground wood production (AWP). We started by statistically modelling the diameter growth of individual trees and used these models to estimate AWP for 142 permanent forest plots. We then used structural equation modelling to explore the direct and indirect pathways which shape rates of AWP. 3. Across the plot network, stand basal area emerged as the strongest determinant of AWP, with densely packed stands exhibiting the fastest rates of AWP. In addition to stand packing density, both tree diversity and soil phosphorus content were also positively related to productivity. By contrast, historical logging activities negatively impacted AWP through the removal of large trees, which contributed disproportionately to productivity. 4. Synthesis. Understanding what determines variation in wood production across tropical forest landscapes requires accounting for multiple interacting drivers – with stand structure, tree diversity and soil nutrients all playing a key role. Importantly, our results also indicate that logging activities can have a long-lasting impact on a forest’s ability to sequester and store carbon, emphasizing the importance of safeguarding old-growth tropical forests.This study was funded through a grant from the Cambridge Conservation Initiative Collaborative Fund entitled “Applications of airborne remote sensing to the conservation management of a West African National Park”. T.J. was funded in part through NERC grant NE/K016377/1. A.C.S. was funded in part through a grant from the Percy Sladen Memorial Fund

Cultural Effects on Sorghum Varieties Grown, Traits Preferred, and Seed Management Practices in Northern Ethiopia

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