Simulating light quantity and quality over plant organs using a ray-tracing method to investigate plant responses in growth chambers

Ray-tracing models enable the assessment of light quantity and quality intercepted by plant organs, supporting biological studies in growth chambers with varying light conditions. However, their validation within canopies and clear usage methods remain limited. This work establishes a reliable method for using these models. The method includes i) accounting for the intensity and spectrum of light sources in the calibration procedure; ii) a generic calibration strategy using a few well-placed light measurement points based on chamber geometry. It evaluates the method to simulate light phylloclimate at the organ scale across biologically relevant wavebands of contrasted widths and properties. Using the SEC2 light simulation framework, three virtual experiments were conducted in a growth chamber, with and without rose plants. Inputs included chamber geometry, material optical properties, lamp emissions, and digitised plant mock-ups. Simulations were compared with spectral measurements at various chamber positions and sensor orientations, both without plants and inside a canopy. Results showed high accuracy in replicating spatial light variability, with RMSE ranging 0.011 to 0.021 and 0.014–0.038 μmol m-2s-1nm-1 across different wavebands and sensor orientations, for vertical and horizontal transects, respectively. Applying this approach to a case study demonstrated its effectiveness in formulating new biological hypotheses regarding the role of local light in regulating bud outgrowth. This was achieved by highlighting differences in phylloclimate induced by variations in plant architecture. This work thus provides a comprehensive framework for facilitating the application of ray-tracing models in growth chamber studies

Short-term impacts of selective logging on forest elephants

Although forest elephants (Loxodonta cyclotis) are known to use logged forests, the impact of selective logging on this critically endangered species has never been well established. Considering the potential of some logged areas to serve as other effective area-based conservation measures, aligning with the Convention on Biological Diversity's 30/30 initiative, we aimed to assess the short-term impacts of logging on three population parameters: the presence, abundance, and activity of forest elephants. Combining camera traps and dung surveys before and after logging operations, we assessed the response of forest elephants in a certified timber concession in Gabon. Encouragingly, we found no negative effects of logging on the three population parameters studied. There was no discernible change in the presence of elephants after logging, and their abundance actually increased (relative abundance index from 1.56 to 2.59; p-value 0.0139) at one of the study sites. Activity patterns were also unaffected, showing sustained activity during daylight hours. We also identified the logging-associated factors that have significantly influenced forest elephant's abundance. Notably, logging intensity, as measured by the average number of trees harvested per hectare, and road density were positively correlated with the number of forest elephant observations (logging intensity effect: 0.2992, p-value 0.035; road density effect: 0.3628, p-value 0.060). As global conservation goals evolve, this research provides important insights into the coexistence of well-managed industrial activities and the conservation of endangered species, highlighting the need to include responsibly managed timber concessions in future conservation strategies. It also underscores the importance of wider adoption of sustainable practices such as low-impact logging, promoted by certification schemes such as FSC or PEFC, to secure the future of central African forests and their unique wildlife

When farmers' knowledge matters: Improving epidemiological understanding of Peste des petits ruminants in northern Nigeria

Peste des petits ruminants (PPR) is an endemic disease of sheep and goats in Nigeria and represents a major threat to the livelihoods of smallholders. Understanding the epidemiology of this disease and its management by livestock farmers is essential for developing appropriate surveillance and control programmes. This study aimed to enhance the knowledge about PPR by conducting a large-scale survey in 52 villages in Plateau, Bauchi and Kano states in the northern part of Nigeria. Our approach involved holding focus group discussions with farmers, both men and women, to collect their knowledge about the disease and to understand their perspectives on its management. The results showed that farmers use several different terms to refer to diseases that are likely to be PPR, and that these same terms might also be used to refer to diseases caused by other infectious agents. Farmers rarely call on veterinary services to prevent the disease and vaccination is seldom practiced. Disease control is attempted using conventional treatments, with or without veterinary supervision, or using traditional therapies. There is limited or poor implementation of good farming practices such as biosecurity measures. This study has increased our understanding of PPR and its management in areas with limited public and private veterinary services. In addition, it has also fostered trust between scientists and communities, paving the way for future participatory action research programmes

Co-designing zoonotic diseases prevention practices when people depend on wild meat

In the face of the escalating frequency of diseases emergences originating from wildlife, the development of reliable strategies for controlling zoonotic diseases transmission at the interface between wildlife and human is becoming a global priority. Rural communities whose subsistence is based on hunting for wild meat extraction are natural targets of such interventions, because of their regular contacts with wildlife. To date there have been few attempts at building preventive sanitary strategies taking into account the socioeconomic and institutional constraints in which wild meat systems operate. The study presented here, conducted in eastern Gabon, aimed at conceiving risk-reduction strategies of zoonotic diseases transmitted from wildlife in a two-phase approach, namely (1) an assessment phase, based on a survey on risk knowledge and practices conducted with members of communities living on wild meat, and (2) a co-design phase based on focus group discussions to identify acceptable prevention strategies aimed at limiting the contacts creating the major risks of exposure to zoonoses infections. The use of participatory methods aiming at eliciting issues and solutions from the participants, enabled the conception of strategies that were adapted to the context and well accepted by stakeholders at different stages, namely the track, capture, transport of wild animals, the butchering of carcasses, cooking and consumption process. However, some limitations to the effective application of the strategies can be anticipated notably because of (1) the current low and biased perception of zoonotic risks by wild meat actors, and (2) the economic incentives for maintaining risky behaviors like the capture and trade of live animals and the consumption or sale of animals found dead or displaying signs of disease infection

Summary document of the International Conference on Local Bioenergy for production units, BLP2025, 28-30 January 2025, Montpellier (France)

The speeches and discussions at the three-day BLP 2025 conference highlighted the challenges of developing small-scale bioenergy technologies, especially in terms of their economic viability and the reduction of harmful emissions. Compromises must be continuously made between the technical performance of equipment, production costs, and ease of use (ergonomics). Multiple presentations highlighted the need and importance of developing bioenergy for productive purposes, especially on small, potentially decentralized scales. This type of renewable energy is poised to become an increasingly important part of the energy mix of both northern and southern countries. The value of this type of international conference lies in its ability to provide much-needed practical input that is vital for shaping development aid policies and strategies. The conference provided an opportunity to take stock of recent technical advances, some of which show particular promise, and to reinforce the conviction that biomass can play a key role in a sustainable energy mix. In particular, scenarios for scaling up and circular economies encouraged the emergence of innovative solutions that optimize resource use while minimizing environmental impacts. These avenues offered valuable insights into overcoming existing obstacles and accelerating the transition to more sustainable and resilient energy systems. The event also helped strengthen a multidisciplinary community of researchers and companies engaged in small-scale bioenergy for productive use

Improvement of iron and β-Carotene bioaccessibility in complementary foods: Biofortification of local crops With organic residual products and microorganisms

Micronutrient deficiencies remain a great public health challenge worldwide with iron, zinc, and vitamin A being the most problematic. It has been shown that biofortification through agronomic strategies can increase their micronutrient content, but data on the bioavailability remain limited. In Senegal, consumption of cereals and legumes is high, and orange-fleshed sweet potato (OFSP), rich in β-carotene, has been introduced a decade ago. The objective of the present work was to assess the bioaccessibility of iron, zinc, and β-carotene in local complementary foods prepared with millet, cowpea, and OFSP alone or in combination, produced using different agronomic biofortification strategies. Organic residual products were used alone or in combination with microorganisms to produce the abovementioned crops that were used to prepare the complementary foods. Static in vitro digestion was performed to assess the bioaccessibility of the micronutrients, according to a harmonized protocol. The two organic residual products had different effect, as the cow dung alone was inefficient to increase iron and zinc contents as well as their bioaccessibility in millet porridges. However, the use of poultry litter alone or in combination with microorganisms increased iron bioaccessibility in cooked cowpea (27%–29%) compared to the non-biofortified counterpart (9%). Surprisingly, bioaccessible β-carotene was significantly higher (4.1%) in sample of mashed OFSP biofortified with the combination of the different agronomic strategies than in the others (1.4%–2.5%). Portions (150 g) of porridge prepared from the three biofortified crops would cover up to 100% of the daily vitamin A requirements of children aged 6–23 months. The use of a combination the most promising varieties of crops, together with the agronomic strategies, would be a complementary approach to sustainability limit micronutrient deficiencies in a context of monotonous diets

Status of Hiptage benghalensis (L.) Kurz (Malpighiaceae). A review

Hiptage benghalensis (L.) Kurz (Malpighiaceae) is a perennial woody vine originating from the Indochinese rainforest. The vine is invasive in the majority of areas where it has been introduced and is a major biological concern, recognized by the IUCN as one of the 100 most invasive species in the world. Invasions of H. benghalensis cause severe negative impacts on the biodiversity of the areas it colonizes, particularly the Mascarene Islands, which are among the world's top biodiver- sity hotspots. Current management strategies, which include herbicides and mechanical control, are not sustainable and alternatives are urgently needed. This review aims to summarize the existing knowledge on H. benghalensis, covering aspects such as taxonomy, description, origin and geographical distribution, biology, ecology, associated habitats and biocenosis, economic importance and management. This essential information will help inform the development of a classical biological control program to assist in the management of the plant

Linking effect traits of soil fauna to processes of organic mattertransformation

Soil organic matter (SOM) transformation processes are regulated by the activities of plants, microbes, and fauna. Compared with plants and microbes, effects of soil fauna are less understood because of their high taxonomic and functional diversity, and mix of direct and indirect effect mechanisms. Trait-based approaches offer a generic perspective to quantify mechanistic relationships between soil fauna and SOM transformations, including decomposition, translocation, and stabilisation of organic carbon. Yet, at present, we lack a consensus concerning relevant key effect traits of soil fauna (i.e. those affecting ecosystem functioning). Here, we address this knowledge gap by focusing on relationships between soil fauna effect traits and SOM transformations. Based on existing literature, we identify key processes linked to SOM transformations, and fauna effect traits universally applicable across taxa and soil types, and discuss the process-trait links. We define eight SOM transformation processes that are directly affected by soil fauna: (i) litter mass loss, (ii) litter fragmentation, (iii) SOM aggregation in faeces, (iv) SOM aggregation in soil mineral particles, (v) decomposition of faeces, (vi) SOM and mineral translocation, (vii) pore space creation and maintenance and (viii) SOM stabilisation. We link these processes to general effect traits classified into four categories: (a) food selection and ingestion, (b), digestion and excretion, (c) mobility, and (d) body mass and metabolic rate. We also propose proxies when effect trait measurements are laborious. The proposed links between effect traits and SOM transformation processes need to be validated in targeted experiments. We urge researchers to obtain quantitative experimental data, together with metabolic approaches, to integratively quantify soil fauna contributions to soil functioning