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Greater Flexibility in Payments for Ecosystem Services: Evidence from an RCT in the Amazon
No full textIn Payment for Ecosystem Services (PES) programs, incentive payments conditional on zero deforestation do not always match the time profile of landowners' opportunity costs. In this study, we examine the impact of adding some flexibility to PES contracts to allow landowners the possibility of receiving part of the financial incentive if some deforestation is detected during the contract period. We ran a pilot PES program in the Brazilian Amazon during the last years of Jair Bolsonaro's mandate, at a time when incentives to deforest were strong. Using the Becker-DeGroot-Marschak (BDM) mechanism, we implemented a PES procurement auction to elicit landowners' reservation prices for forest conservation. We embedded the BDM auction in a randomized controlled trial (RCT), which included one control group and two PES treatment groups of about 150 voluntary landowners each. In line with theoretical predictions, we found that, while the flexible PES contract allowing some deforestation saved slightly more forest, the fixed payment contract requiring zero deforestation exhibited a higher benefit-cost ratio
A new approach combining microwave heat pulse and infrared thermography for non-invasive portable sap flow velocity measurement
No full textInternational audienceXylem sap flow measurement is a key method to quantify plant water use and assess the responses to environmental conditions and climatic change. However, available methods are generally invasive and of limited portability. This paper presents a non-invasive approach called TIMFLOW that combines microwave heat pulse and infrared thermography, while having a high portability and versatility potential. The methodology was tested in laboratory conditions for black poplar (Populus nigra) stems of various diameters (10–45 mm) and for the known sap flow velocity range (10–100 cm h−1). The heat pulse was generated by microwaves with a power amplifier supplying a bi-quad antenna at 2.45 GHz frequency located near the stem. The scene was filmed using a relatively low-cost light and compact InfraRed (IR) thermography camera. A stem temperature map was used to determine the heat pulse propagation velocity. The calculated heat velocity was highly correlated with the applied flow velocity with a unique relationship regardless of the diameter. The latter result confirms the equation of Marshall (1958) which links the sap velocity to the heat velocity with a vessel fraction of around 25 % within samples. The feasibility of outdoor measurements was also successfully tested. The assumed potentials and limitations of the proposed methodology are discussed. In summary, the study demonstrates the concept and validates, in woody stems, this new methodology for non-invasive portable sap flow velocity measurement
The vocal expression of emotions in human and non human primates: an evolutionary approach: L’expression vocale des émotions chez le primate humain et non humain : une approche évolutive
No full textL’Homme n’a pas le monopole du coeur. Le cadre conceptuel fourni par la théorie de l’évolutionde Darwin et les similarités relevées par l’auteur dans l’expression des émotions entre différentesThe conceptual framework provided by Darwin's theory of evolution and the similarities observedby the author in the expression of emotions across different animal species, including humans,have led to consider this universal phenomenon, observed at the interspecific level, as acontinuum. Recent research in ethology and anthropology supports the idea that all livingorganisms must face the same challenges for survival, namely: the search for food, the choice ofa sexual partner and last but not least, defense against aggressors. In this context, variousemotional states, including anger, fear, joy, surprise, and disgust, are seen as adaptive means torespond to these challenges. It appears thus irrelevant to separate humans from other animalsregarding emotional behavior. The aim of this contribution is to demonstrate that the scientificstudy of emotions is intrinsically linked to the theory of evolution and to emphasize the similaritiesin emotional vocalizations between human and non-human primates.L’Homme n’a pas le monopole du coeur. Le cadre conceptuel fourni par la théorie de l’évolutionde Darwin et les similarités relevées par l’auteur dans l’expression des émotions entre différentesespèces animales – dont l’humain – l’ont conduit à envisager ce phénomène universel, observéà l’échelle interspécifique, comme un continuum. Les travaux récents en éthologie et enanthropologie soutiennent l’idée que tout organisme vivant doit faire face aux mêmes défis poursurvivre, soit : la recherche de nourriture, le choix d’un partenaire sexuel, la défense contre lesagresseurs et que, dans ce contexte, les différents états émotionnels, notamment : la colère, lapeur, la joie, la surprise et le dégout, constituent autant de moyens adaptatifs pour y répondre. Ilsemble ainsi peu pertinent de séparer l’humain des autres animaux pour ce qui relève ducomportement émotionnel. L’objet de cette contribution est de montrer en quoi l’étude scientifiquedes émotions est intrinsèquement liée à la théorie de l’évolution et de souligner les similarités desvocalisations émotionnelles entre primates humain et non-humains
The evolutionary history of three Baracoffea species from western Madagascar revealed by chloroplast and nuclear genomes
No full textInternational audienceThe wild species of the Coffea genus present a very wide morphological, genetic, and biochemical diversity. Wild species are recognized more resistant to diseases, pests, and environmental variations than the two species currently cultivated worldwide: C. arabica (Arabica) and C. canephora (Robusta). Consequently, wild species are now considered as a crucial resource for adapting cultivated coffee trees to climate change. Within the Coffea genus, 79 wild species are native to the Indian Ocean islands of Comoros, Mayotte, Mauritius, Re ´union and Madagascar, out of a total of 141 taxa worldwide. Among them, a group of 9 species called "Baracoffea" are particularly atypical in their morphology and adaptation to the sandy soils of the dry deciduous forests of western Madagascar. Here, we have attempted to shed light on the evolutionary history of three Baracoffea species: C. ambongensis, C. boinensis and C. bissetiae by analyzing their chloroplast and nuclear genomes. We assembled the complete chloroplast genomes de novo and extracted 28,800 SNP (Single Nucleotide Polymorphism) markers from the nuclear genomes. These data were used for phylogenetic analysis of Baracoffea with Coffea species from Madagascar and Africa. Our new data support the monophyletic origin of Baracoffea within the Coffea of Madagascar, but also reveal a divergence with a sister clade of four species: C. augagneurii, C. ratsimamangae, C. pervilleana and C. Mcphersonii (also called C. vohemarensis), belonging to the Subterminal botanical series and living in dry or humid forests of northern Madagascar. Based on a bioclimatic analysis, our work suggests that Baracoffea may have diverged from a group of Malagasy Coffea from northern Madagascar and adapted to the specific dry climate and low rainfall of western Madagascar. The genomic data generated in the course of this work will contribute to the understanding of the adaptation mechanisms of these particularly singular species
Oak regeneration facing deer browsing: Can competition between saplings offset the diversion effect? A simulation experiment
No full textInternational audienceThe constraint caused by wild ungulates on forest regeneration is increasing worldwide. Hypotheses for plant association effects predict that species susceptible to herbivory can gain protection from other neighbouring plant species. In theory, such interactions could help limit the impact of browsing on the regeneration of specific tree species. However, the presence of neighbouring species can also result in increasing competition for resources between species. The resultant effects on forest regeneration of these interactions, both positive (protection against herbivores) and negative (inter-specific competition) are still unclear. To gain insight, we coupled models of browsing by roe deer (Capreolus capreolus) and of forest dynamics to simulate trajectories of oak (Quercus petraea (Matt.) Liebl.) regeneration admixed with species of contrasted palatability and growth rate under different scenarios of browsing pressure and initial sapling density. We also investigated how releasing oak saplings from all or specific neighbours during the simulation affect regeneration. We found that admixed species composition had a relatively weak effect on the density of oak recruits, but a strong effect on the duration of the regeneration phase. Oak regenerated faster when admixed with species of intermediate growth and low palatability (Fagus sylvatica) than with species of fast growth and high palatability (Carpinus betulus L.), except at intermediate sapling density and high browsing pressure where we found the opposite. Releasing oak from all competitors was most effective in promoting oak regeneration when admixed with both species together, although the benefit of competition release was much weaker at high browsing pressure. Lastly, we found that at low initial sapling density (i.e., 10 saplings/m2), oak regeneration was driven only by browsing and the effect of admixing species became negligible. Our study showed that admixing oak with palatable neighbours impedes rather than improves oak regeneration due to increased competition for resources. As such, we suggest that the benefits of herbivore diversion can be off-set by increased inter-specific competition
Half a Century of Controversy: The Neutralist/Selectionist Debate in Molecular Evolution
No full textInternational audienceThe neutral and nearly neutral theories, introduced more than 50 yr ago, have raised and still raise passionate discussion regarding the forces governing molecular evolution and their relative importance. The debate, initially focused on the amount of within-species polymorphism and constancy of the substitution rate, has spread, matured, and now underlies a wide range of topics and questions. The neutralist/selectionist controversy has structured the field and influences the way molecular evolutionary scientists conceive their research
TETIS @ Challenge TextMine 2024 : "Reconnaissance d'entités géographiques dans un corpus des Instructions nautiques"
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On the impact of re-mating and residual fertility on the Sterile Insect Technique efficacy: case study with the medfly, Ceratitis capitata
No full textInternational audienceThe sterile insect technique (SIT) can be an efficient solution for reducing or eliminating certain insect pest populations. It is widely used in agriculture against fruit flies, including the Mediterranean fruit fly (medfly), Ceratitis capitata. The re-mating tendency of medfly females and the fact that the released sterile males may have some residual fertility could be a challenge for the successful implementation of the SIT. Obtaining the right balance between sterility level and sterile male quality (competitiveness, longevity, etc) is the key to a cost-efficient program. Since field experimental approaches can be impacted by many environmental variables, it is difficult to get a clear understanding on how specific parameters, alone or in combination, may affect the SIT efficiency. The use of models not only helps to gather knowledge, but it allows the simulation of a wide range of scenarios and can be easily adapted to local populations and sterile male production.In this study, we consider single- and double-mated females. We first show that SIT can be successful only if the residual fertility is less than a threshold value that depends on the basic offspring number of the targeted pest population, the re-mating rates, and the parameters of double-mated females. Then, we show how the sterile male release rate is affected by the parameters of double-mated females and the male residual fertility. Different scenarios are explored with continuous and periodic sterile male releases, with and without ginger aromatherapy, which is known to enhance sterile male competitiveness, and also taking into account some biological parameters related to females that have been mated twice, either first by a wild (sterile) male and then a sterile (wild) male, or by two wild males only. Parameter values were chosen for peach as host fruit to reflect what could be expected in the Corsican context, where SIT against the medfly is under consideration.Our results suggest that ginger aromatherapy can be a decisive factor determining the success of SIT against medfly. We also emphasize the importance of estimating the duration of the refractory period between matings depending on whether a wild female has mated with a wild or sterile male. Further, we show the importance of parameters, like the (hatched) eggs deposit rate and the death-rate related to all fertile double-mated females. In general, re-mating is considered to be detrimental to SIT programs. However, our results show that, depending on the parameter values of double-mated females, re-mating may also be beneficial for SIT.Our model can be easily adapted to different contexts and species, for a broader understanding of release strategies and management options
Achieving sustainability in family farming
No full textInternational audienceWhile small-scale farming households constitute a large part of the population, as well as the producers of the majority of food supplies in low- and middle-income countries, major gaps remain in the ability to produce reliable solutions to achieve sustainability in family farming.This special issue aims to address some blind spots and shed new light on sustainability in family farming using sustainability science. The publications presented in this special issue will enable readers to grasp the importance of a detailed and situated understanding of the needs and practices of family farming, as well as the importance of involving farmers and their families in our research to find solutions for improving the sustainability of family farming that will benefit everyone
NDVI estimation using Sentinel-1 data over wheat fields in a semiarid Mediterranean region
No full textInternational audienceAnnual crop monitoring is a key parameter for managing agricultural strategies. Several studies have relied on remote sensing products such as the normalized difference vegetation index (NDVI) as a vegetation dynamic metric. However, the dependence of optical data on weather conditions limits its availability. In this study, we reconstruct the NDVI time series of wheat fields using the moving averages of the Sentinel-1 normalized VH/VV cross-polarization ratio (IN) and the interferometric coherence in VV polarization over wheat selected fields in a semiarid site in Tunisia during two seasons, from 2018 to 2020. The crop cycle is divided into two periods: before and after the heading phase, which occurs in approximately the middle of March. Due to the volume-scattering impact, the second phase is divided into the ripening and maturation phase (NDVI >= 0.4) and senescence phase (NDVI <0.4). To estimate the NDVI values, different methods are used: curve-fitting equations and machine learning regressors such as the random forest (RF) and the support vector regressor (SVR). Low root mean square error (RMSE) values characterize NDVI estimation during the first period. In the second period, the RMSE values reach 0.06 when the NDVI is lower than 0.4. When the NDVI values exceed 0.4 in the second period, lower accuracy marks the NDVI estimation using the curve-fitting equations as a function of IN or coherence. Relative low accuracy characterizes the regression algorithms' estimations when NDVI >= 0.4 compared to their performance during the aforementioned periods. The proposed approach was tested on different wheat fields. The NDVI estimations are characterized by RMSE values varying between 0.12 and 0.19. The use of RF and SVR outperformed the curve-fitting methods with an RMSE equal to 0.12. The present findings revealed the high accuracy of the proposed approach to estimate the missing values of wheat fields NDVI values during the vegetation development period until heading and the senescence phase. The presence of the mutual effect of the vegetation water content and its volume complicated the NDVI estimation using the C-band data