Paper short abstract:

Nature-based solutions (NbS) are strategies that address societal challenges while also meeting biodiversity objectives. In this systematic review, we attempt to document the suite of NbS in the savannah belt of Africa to assess their potential to address the unique challenges of these ecosystems.

Paper long abstract:

Nature-based Solutions (NbS) have gained traction in recent years as a new way of framing the discourse surrounding climate change adaptation and mitigation. The theory is that by using nature as the template for solutions to societal challenges, efficiencies can be gained in cost and effectiveness, while at the same time achieving multiple co-benefits. NbS have been demonstrated in several ecosystems and economic sectors around the globe, but when it comes to savanna ecosystems in Africa, there is still a lack of clarity of what is meant by NbS. We undertake a systematic review of literature in the savanna belt of Africa- stretching from Senegal to Tanzania- to understand what constitutes NbS in the context of savannahs. We document the status of these NbS, their uptake in different countries, the evidence basis, the challenges they face, and which ones have the most promise for up-scaling. This review examines 3,448 journal articles from 2018-2022 and filters them following the PRISMA procedures. Results show that there are a wide variety of techniques and strategies that loosely fall under NbS in savannah ecosystems. These can be categorized according to type, approach, sector, and societal challenge addressed. There are varying degrees of evidence for each of these solutions, and varying levels of uptake within local communities. Solutions with the most promise are those that are both inspired and implemented via nature that have an indigenous knowledge basis, achieve multiple co-benefits, and have private sector and scalability potential.

Paper short abstract:

This paper focuses on the recent tree planting projects initiated in 2009-2022 in rural Africa. These projects have attracted huge political and media attention as a “simple” significant planning solutions for the environment. They are relevant to discuss when addressing climate change in Africa.

Paper long abstract:

This paper focuses on the recent tree planting projects initiated in 2009-2022 in rural Africa. These projects have attracted huge political and media attention as a “simple” significant planning solutions for the environment. They are important to discuss not only for their role but also for the expected improvements to addressing climate change, controlling desertification, and promoting the wellbeing of their populations. Migration to African cities has caused several challenges like urban poverty and slum proliferation and a broad depletion of the environment. Various responses through different projects have emerged particularly on the environmental planning and management of cities and rural areas. Some projects have been highly publicized but not really implemented, and there are little monitoring and evaluation on trees planting process by governments. Consequently, several critical points emerge on planning in African countries that should reconsider urban planning with a clear focus on the role of green infrastructure because of their extensive social benefits and supportive capacity for any significant sustainable development. In this paper we offer an overview of the projects that have been presented and/or implemented in African rural areas.

Paper short abstract:

The lowlands of Baringo are semi-arid and the vegetation is dominated by A. tortilis and P. juliflora. We aim at understanding the distribution patterns of those species and its relationship to drought tolerance. We present first results on water use efficiency and relate them to soil measurements.

Paper long abstract:

Full list of authors: D. Otieno, N. Nyamari, D. Ondede, T. Kramm, P. Olewe, A. Kolb, G. Bareth, L. Biber-Freudenberger, C. Bogner

The lowlands of Baringo County (900 to 1200 m asl) are semi-arid with a bi-modal rainfall averaging 635 mm annually against a mean annual evaporation rate of 1,100 mm. The average minimum and maximum air temperatures are 20 and 30 °C. The vegetation is dominated by the genus Acacia, mostly overrepresented by the species A. tortilis, endemic to the lowlands and Prosopis juliflora, a neophyte that was introduced in the area in the 1970s. While A. tortilis is sedentary and remains relatively resistant to drought stress in their increasingly dry environment, P. juliflora is more versatile and prolific and has spread into most parts of the lowlands. Factors that promote this distribution pattern of the two species, however, remain unclear, but are likely to be related to their ability to withstand drought stress. In this study, we examine the mechanisms of stress resistance employed by A. tortilis and P. juliflora within their natural distribution range in Marigat, Baringo County. We present results of different data collection methods deployed to investigate water sources, root uptake, transport, and use by trees. These results are linked to our first soil measurements conducted in a fish-bone design along transects of rural roads in Marigat to understand how hydrological changes resulting from road influence the distribution patterns of A. tortilis and P. juliflora in Baringo County.

Paper short abstract:

The various cases presented come from various communities in the ASALs of Kenya and show evidence-based approaches that are useful and sustainable. Indigenous tree seedlings play a very critical role in restoration of degraded lands owing to their adaptability and resilience in dryland areas.

Paper long abstract:

Arid and Semi-arid regions are facing increased impacts of climate change resulting to challenges which have resulted in biodiversity and soil fertility loss. It is highly recognized that trees contribute a range of ecosystem services in urban environments and through their various value chains contribute to livelihood support for many in sub-Saharan Africa. Rehabilitation using indigenous tree species in Kenya faces challenges as the country lacks guidelines on species site matching, activities on soil and water conservation in a scale large enough to ensure the rehabilitation actions are sustainable. The case for forestry, soil and water conservation suitable activities needs to be disseminated and to contribute to achieving food security under climate change. The various cases presented come from various communities in the ASALs of Kenya and show evidence-based approaches that are useful and sustainable. Indigenous tree seedlings play a very critical role in restoration of degraded lands owing to their adaptability and resilience in dryland areas. Development of indigenous seedlings in tree nurseries is therefore an exercise of great essence. This has caused a need for review of practices to improve performance of the seedlings in the nurseries to aid in quality improvement, thus demonstrating easy changes to increase seedlings survival and quality. This will be followed up by assessment of the ecological performance of rehabilitation efforts in two arid and semi-arid (ASAL) sites with varying number of tree species and a demonstration of large-scale restoration of degraded lands to support both community and biodiversity using technologies that are easy to adopt. Then finally an evaluation of a high potential area to show opportunities for practice change regarding manure management.

Paper short abstract:

Côte d'Ivoire has experienced an expansion of cashew cultivation in its savannah areas, leading to an increasing loss of biodiversity. Agroforestry systems involving wild edible plants represents a nature-based solution to mitigate this trend while diversifying communities incomes.

Paper long abstract:

More than half of Côte d'Ivoire is covered by savannah vegetation. This area is facing a massive destruction for the establishment of cashew plantations, partly due to climatic and economic hazards. For only a decade, the country has become the first exporter of cashew nuts. Cashew plantations are owned by men and women have less and less land for their food crops. In addition, cashew cultivation is carried out in monoculture systems resulting in a high loss of plant biodiversity. Edible and multipurpose wild plants-based agroforestry (EMWPbA), is a nature-based solution to mitigate this trend. Indeed, this is a way for the diversification of incomes of communities and the conservation of species able not only to sequester carbon but also to attract pollinators to the cashew trees. Studies have been conducted in the country to identify candidate plant species for this purpose. Interviews were used to gather ethnobotanical information from communities. The abundance of target species in the vegetation was assessed. A total of 81 edible wild plants were identified. Nineteen species (27.14 % of taxa), are well known and well exploited by people. Twenty-two (22) species were identified as promising in agroforestry. The highest density was observed with Vitellaria paradoxa (93.6 ind. ha-1) and the lowest one with Ricinodendron heudelotii (2.3 ind. ha-1) and Tamarindus indica (2.3 ind. ha-1). Cashew plantations are characterized by low densities of the target species. We conclude that the valorization of edible wild plants can encourage farmers to adopt agroforestry.

Paper short abstract:

Frequent land search for cash crops in savannah zones of Côte d'Ivoire has a significant impact on the quality of ecosystems and their soils. Ecosystem engineers, whose roles are no longer to be demonstrated, can provide a solution for sustainable agriculture, in line with the potential of soil.

Paper long abstract:

The ecosystems engineers are considered as a prime resource of agroecosystems because they regulate the soil biological process. Among them, earthworms and soil-feeding termites having common diet and similar roles on the soil structure and functioning have been studied. The work was focused on the influence of the nest of Cubitermes subcrenulatus (Termitinae; Termitidae) on the distribution of earthworm communities in the humid savannas of the Lamto reserve (central Côte d’Ivoire). In total, 15 living nests of Cubitermes subcrenulatus remote the one of the other of 200 m have been identified randomly in a forest island using the Tropical Soil Biology and Fertility monoliths’ method around Cubitermes nests. Eight species of earthworms were collected around Cubitermes nests, with dominance and high observation frequency of subterranean earthworms. Earthworms and termites have opposite distributions in the soil with increasing distance from the Cubitermes nest. The presence of Cubitermes subcrenulatus nests impacts the vertical and horizontal distribution of earthworms. Despite the presence of Cubitermes subcrenulatus nests, the respective ecological niches of the earthworms change while maintaining the coexistence with the termites.

Key words: Termites, Earthworms, Ecological niche, Soil, Savannah, Côte d’Ivoire

Paper short abstract:

This study finds that collective shocks, in comparison to individual shocks, reduce cooperation more for farmers than herders. Herders living in shock-prone environments show to be more resilient to collective shocks, e.g. extreme climate events, and have higher levels of cooperation.

Paper long abstract:

Climate change has a rising impact on rural livelihoods, particularly for those dependent on stable rainfall patterns, as on rain-fed agriculture. Especially the Sahel region is stressed due to climate variability, including extreme heat, shortening of rainfall season and more frequently occurring, extreme hydrometeorological events. For decades, disputes over water and grazing opportunities between sedentary farmers and semi-nomadic herders have been ongoing, but are becoming more frequent in relatively peaceful areas, as droughts and lack of rainfall push populations from the Sahelian drylands into more fertile areas. Climate shocks and competing livelihood strategies are considered to be some of the underlying causes that can bring existing fragile contexts out of balance, and cause farmer-herder tension to escalate. Most extreme climatic events carry covariate risks that could potentially affect whole communities, and a better understanding of responses to such shocks is needed. In particular, differences associated to strong group identities among sedentary farmers and semi-nomadic herders could affect cooperation patterns and trigger ethnic tensions.

This study aims to answer the central question: How do individual versus collective shocks affect cooperation between farmer and herder communities? We conducted a lab-in-the-field experiment, based on a public good game, with farmers and herders in Senegal. We find that collective shocks contribute to cooperation towards group members with shared identity, but have an opposing effect on members from the perceived out-groups. We show that herders show higher cooperation levels compared to farmers and that herders are more robust to collective shocks in their cooperation levels.

Paper short abstract:

This paper analyses three aspects of development projects to combat desertification: 1) their perceptions of desertification and its causes, 2) the measures to combat desertification and their outcome, 3) the changes over time.

Paper long abstract:

Namibia is one of the driest countries in the world and drought events and intensity increased in the last decades and will increase in the future. Climate conditions and various socio-economic and structural factors have led to rangeland degradation in different parts of the country, especially in the communal areas. Here, a large part of the population depend on subsistence livestock farming to make a living. Therefore, rangeland degradation in these territories constitute a significant risk not only to biodiversity, but also to livelihoods. Against this background, five different development projects to combat desertification (SARDEP, NAPCOD, DMP, CPP, LDN) were implemented successively from 1991 until 2018 in the communal farming areas of the Waterberg region mainly under the umbrella of UNCCD. These development projects are important platforms to bring together international treaties (UNCCD), international cooperation and UN agencies, Namibian ministries, extension services, consulting firms, NGOs and local communal farmers. The aim of this paper is to analyse three aspects, firstly, the projects’ perceptions of desertification and its causes, secondly, the projects’ measures to combat desertification and their outcome, and thirdly the changes over time. Project measures address monitoring, trainings, practices, and policies on the local, but also on the national level. We analyse project reports and interviews with key informants from the mentioned projects with Qualitative Content Analysis. The identified local and national measures can inform future scenarios to adapt to climate change in Namibia and drylands in other Sub-Sahara African countries.