Tree size diversity is the major driver of aboveground carbon storage in dryland agroforestry parklands.

Despite the importance of agroforestry parkland systems for ecosystem and livelihood benefits, evidence on determinants of carbon storage in parklands remains scarce. Here, we assessed the direct and indirect influence of human management (selective harvesting of trees), abiotic factors (climate, topography, and soil) and multiple attributes of species diversity (taxonomic, functional, and structural) on aboveground carbon (AGC) stocks in 51 parklands in drylands of Benin. We used linear mixed-effects regressions and structural equation modeling to test the relative effects of these predictors on AGC stocks. We found that structural diversity (tree size diversity, HDBH) had the strongest (effect size ß = 0.59, R2 = 54%) relationship with AGC stocks, followed by community-weighted mean of maximum height (CWMMAXH). Taxonomic diversity had no significant direct relationship with AGC stocks but influenced the latter indirectly through its negative effect on CWMMAXH, reflecting the impact of species selection by farmers. Elevation and soil total organic carbon content positively influenced AGC stocks both directly and indirectly via HDBH. No significant association was found between AGC stocks and tree harvesting factor. Our results suggest the mass ratio, niche complementarity and environmental favorability as underlying mechanisms of AGC storage in the parklands. Our findings also highlight the potential role of human-driven filtering of local species pool in regulating the effect of biodiversity on AGC storage in the parklands. We conclude that the promotion of AGC stocks in parklands is dependent on protecting tree regeneration in addition to enhancing tree size diversity and managing tall-stature trees.

Horizon scanning to assess the bioclimatic potential for the alien species Spodoptera eridania and its parasitoids after pest detection in West and Central Africa.

BACKGROUND: The southern armyworm (SAW) Spodoptera eridania (Stoll) (Lepidoptera: Noctuidae) is native to the tropical Americas where the pest can feed on more than 100 plant species. SAW was recently detected in West and Central Africa, feeding on various crops including cassava, cotton, amaranth and tomato. The current work was carried out to predict the potential spatial distribution of SAW and four of its co-evolved parasitoids at a global scale using the maximum entropy (Maxent) algorithm. RESULTS: SAW may not be a huge problem outside its native range (the Americas) for the time being, but may compromise crop yields in specific hotspots in coming years. The analysis of its potential distribution anticipates that the pest might easily migrate east and south from Cameroon and Gabon. CONCLUSION: The models used generally demonstrate that all the parasitoids considered are good candidates for the biological control of SAW globally, except they will not be able to establish in specific climates. The current paper discusses the potential role of biological control using parasitoids as a crucial component of a durable climate-smart integrated management of SAW to support decision making in Africa and in other regions of bioclimatic suitability. © 2021 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Local perceptions and factors determining ecosystem services identification around two forest reserves in Northern Benin.

BACKGROUND: Ecosystems provide humanity with goods and services known as ecosystem services. The value of these services represents a basis for political decision-making. To be sure that these decisions are made on a valid basis, policymakers require an understanding of the biophysical processes involved. This study was carried out around two forest reserves (Alibori-Supérieur and Ouénou-Bénou) in Northern Benin. It aimed to highlight the knowledge of the surrounding communities and their perceptions about the importance of the ecosystem services provided by these forest reserves as well as the factors that influence their knowledge and perceptions. METHODS: Primary data were collected from 25 group discussions in 25 villages surrounding the forest reserves based on predefined ecosystems services of the Millennium Ecosystems Assessment (MA). Multiple linear regression models were used to examine how socio-economic characteristics of the communities influenced the ecosystem services identification rate. Perceptions of importance, levels of satisfaction, and trends of services provided were analyzed using descriptive statistics. RESULTS: Our results showed that education level, poverty index, household size, and proximity to forests played an important role in the variation in knowledge of ecosystem services (P < 0.05). Provisioning services (such as crops supply, fuelwood, lumber, wild food, and medicinal plants) were mostly identified by the poorest villages located very close to the forests (P < 0.05). The importance of the provided services for well-being has been unanimously recognized. The most recognized cultural services were education and knowledge facilitation (84%) and spiritual value (76%). Climate regulation (84%) and pollination (84%) were the best-known regulating services. However, supporting services (soil formation and pest regulation) that are important for improving production systems were unknown to the communities. CONCLUSION: Education level, poverty index, and village proximity to the forest were important predictors of regulating and supporting services identification. But use of non-tangible services by local rural communities will require more emphasis on targeted environmental education specifically designed according to the needs of each group.

Local knowledge, pattern and diversity of use of Sclerocarya birrea.

BACKGROUND: Growing interest is on food tree species in general, and particularly indigenous fruit tree species in developing countries since they are inherent to most tropical landscapes and serve the dual function of local livelihood support and biodiversity conservation. It is therefore relevant to assess the level of integration of these species in local cultures and the factors affecting them. This study aims at assessing knowledge and uses of Sclerocarya birrea subsp. birrea and factors affecting the use values within and between communities. METHODS: This study combines quantitative and qualitative ethnobotanical approaches to investigate uses and factors affecting the use value of S. birrea subsp. birrea. Nine group discussions as well as 161 individual interviews were held in the dry and typical Sudanian zones. Seven different ethnic groups were involved and the survey focused on local uses and perception of factors affecting the dynamics of S. birrea. RESULTS: The species has a multitude of uses; all organs are used for more than 20 different purposes. The study highlights how gender, local availability, ethnicity and community location interact to influence the utilization value of the species. People living in drier areas with high occurrence of the S. birrea use it more than those living in wetter areas with low occurrence. While domestic and subsistence uses do not appear to threaten the species, carving, clearing and drought stand out as the major causes of its decline. CONCLUSIONS: Many factors and their interactions influence the use pattern of the species within and between communities. When compared to the level of exploitation of S. birrea subsp. caffra in southern Africa, the subspecies birrea is at this point relatively underutilized. A high commercial potential exists due to its simple propagation ability and makes it an interesting agroforestry resource.