Timing of Favorable Conditions, Competition and Fertility Interact to Govern Recruitment of Invasive Chinese Tallow Tree in Stressful Environments

The rate of new exotic recruitment following removal of adult invaders (reinvasion pressure) influences restoration outcomes and costs but is highly variable and poorly understood. We hypothesize that broad variation in average reinvasion pressure of Triadica sebifera (Chinese tallow tree, a major invader) arises from differences among habitats in spatiotemporal availability of realized recruitment windows. These windows are periods of variable duration long enough to permit establishment given local environmental conditions. We tested this hypothesis via a greenhouse mesocosm experiment that quantified how the duration of favorable moisture conditions prior to flood or drought stress (window duration), competition and nutrient availability influenced Triadica success in high stress environments. Window duration influenced pre-stress seedling abundance and size, growth during stress and final abundance; it interacted with other factors to affect final biomass and germination during stress. Stress type and competition impacted final size and biomass, plus germination, mortality and changes in size during stress. Final abundance also depended on competition and the interaction of window duration, stress type and competition. Fertilization interacted with competition and stress to influence biomass and changes in height, respectively, but did not affect Triadica abundance. Overall, longer window durations promoted Triadica establishment, competition and drought (relative to flood) suppressed establishment, and fertilization had weak effects. Interactions among factors frequently produced different effects in specific contexts. Results support our ‘outgrow the stress’ hypothesis and show that temporal availability of abiotic windows and factors that influence growth rates govern Triadica recruitment in stressful environments. These findings suggest that native seed addition can effectively suppress superior competitors in stressful environments. We also describe environmental scenarios where specific management methods may be more or less effective. Our results enable better niche-based estimates of local reinvasion pressure, which can improve restoration efficacy and efficiency by informing site selection and optimal Management

Evaluating the spatial uncertainty of future land abandonment in a mountain valley (Vicdessos, Pyrenees-France) : insights form model parameterization and experiments

International audienceEuropean mountains are particularly sensitive to climatic disruptions and land use changes. The latter leads to high rates of natural reforestation over the last 50 years. Faced with the challenge of predicting possible impacts on ecosystem services, LUCC models offer new opportunities for land managers to adapt or mitigate their strategies. Assessing the spatial uncertainty of future LUCC is crucial for the defintion of sustainable land use strategies. However, the sources of uncertainty may differ, including the input parameters, the model itself, and the wide range of possible futures. The aim of this paper is to propose a method to assess the probability of occurrence of future LUCC that combines the inherent uncertainty of model parameterization and the ensemble uncertainty of the future based scenarios. For this purpose, we used the Land Change Modeler tool to simulate future LUCC on a study site located in the Pyrenees Mountains (France) and 2 scenarios illustratins 2 land use strategies. The model was parameterized with the same driving factors used for its calibration. The defintion of static vs. dynamic and quantitative vs. qualitative (discretized) driving factors, and their combination resulted in 4 parameterizations. The combination of model outcomes produced maps of spatial uncertainty of future LUCC. This work involves literature to future-based LUCC studies. It goes beyond the uncertainty of simulation models by integrating the unceertainty of the future to provide maps to help decision makers and land managers

Diabetic gastroparesis: Therapeutic options

Gastroparesis is a condition characterized by delayed gastric emptying and the most common known underlying cause is diabetes mellitus. Symptoms include nausea, vomiting, abdominal fullness, and early satiety, which impact to varying degrees on the patient’s quality of life. Symptoms and deficits do not necessarily relate to each other, hence despite significant abnormalities in gastric emptying, some individuals have only minimal symptoms and, conversely, severe symptoms do not always relate to measures of gastric emptying. Prokinetic agents such as metoclopramide, domperidone, and erythromycin enhance gastric motility and have remained the mainstay of treatment for several decades, despite unwanted side effects and numerous drug interactions. Mechanical therapies such as endoscopic pyloric botulinum toxin injection, gastric electrical stimulation, and gastrostomy or jejunostomy are used in intractable diabetic gastroparesis (DG), refractory to prokinetic therapies. Mitemcinal and TZP-101 are novel investigational motilin receptor and ghrelin agonists, respectively, and show promise in the treatment of DG. The aim of this review is to provide an update on prokinetic and mechanical therapies in the treatment of DG

Dynamiques de la végétation dans de paysage de pâturages boisés sous influence du changement climatique

International audienceThe sustainable maintenance of the biodiversity rich semi-open-structure of wooded pastures in the Swiss Jura affords higher cattle loads than actually applied. Successional trends induced by climate change further pronounce this demand.Policy-making should consider to maintain current socio-economic constraints, which support cattle stocking in mountain pastures or even improve them

Evolution récente et future des paysages sylvo-pastoraux du Parc Jurassien Vaudois

National audienceLand-use management in silvopastoral landscapes is particularly complex because such ecosystems depend on a subtle equilibrium in the management scheme which aims to provide various ecological goods and services such as fodder, timber and biodiversity, as well as areas for leisure and attractive scenery. In this study we investigated land-use changes in the Parc naturel régional Jura vaudois, and the changes in tree cover density in two pastures using land-use statistics and aerial photographs. A prospective modelling approach was also undertaken on one pasture to assess changes in the landscape structure under two climate scenarios. A general tendency towards segregation between closed forests and open pastures was observed. The agriculture policy has markedly influenced the dynamics of tree cover density, but this effect depended very much on the local situation, for example, the proximity of a village, which allows a better optimization of farm management. The simulation of future development of these landscapes suggests that one might expect large changes in the structure and composition of the vegetation because of climate change. In the long run, areas of high tree densities will expand, and spruce will give way to beech and pine, depending on the warming intensity. Nevertheless, adaptation to new environmental conditions for sustaining ecological goods and services will call for management measures appropriate to the intensity of climate change. Furthermore, an active adaptive management based on experimentation and innovation, as well as allowing collaboration between scientists and land managers will be required to face and mitigate the ecological problems associated with climate change.L’utilisation des paysages sylvo-pastoraux est particulièrement délicate, car leur existence dépend du subtil équilibre de leur gestion qui vise à fournir différents biens et services écologiques, allant de la production d’herbe et de bois à la promotion de la biodiversité, ainsi qu’à la mise à disposition d’aires de détente et de paysages attractifs. Dans cet article, nous présentons une analyse rétrospective, basée sur les données statistiques du territoire, des changements d’utilisation des sols du Parc naturel régional Jura vaudois entre 1985 et 2009, et une analyse rétrospective de la couverture du boisé dans deux pâturages du Jura vaudois par analyse de cinq séries de photographies aériennes anciennes entre 1934 et 2000. Une modélisation prospective sur le long terme (2001 à 3000) est ensuite présentée pour un pâturage de manière à évaluer les changements de paysage selon deux scénarios climatiques de réchauffement et trois variantes de gestion forestière. Les résultats de l’analyse rétrospective montrent une certaine résilience de la structure des paysages sylvo-pastoraux dans la région de montagne du Jura vaudois par rapport aux zones de plus basse altitude, malgré une tendance à la ségrégation entre forêts fermées et pâturages. Les politiques agricoles ont marqué la dynamique des taux de boisement, mais de manière différenciée selon la situation locale, par exemple celle de la proximité d’un village qui permet une meilleure rationalisation de l’exploitation, ou celle de l’éloignement qui favorise l’abandon. Les simulations de l’évolution future de ces paysages suggèrent qu’il faut s’attendre à des changements radicaux dans la composition et la structure de la végétation, provoqués par les changements climatiques. Sur le long terme, les zones à forte densité de boisé auront tendance à s’étendre, et l’épicéa cédera la place au hêtre et/ou au pin sylvestre, selon l’intensité du réchauffement. Pour assurer la durabilité des services des écosystèmes, l’adaptation à ces nouvelles conditions environnementales nécessitera des mesures de gestion qui dépendront elles-mêmes de l’intensité des changements climatiques. Seule une gestion adaptative active, basée sur l’expérimentation et l’innovation, et associant scientifiques et gestionnaires, permettra de limiter l’ampleur des effets des changements climatiques