Methods for measuring gas emissions from naturally ventilated livestock buildings: Developments over the last decade and perspectives for improvement

[EN] The objectives of this paper are: 1) to give an overview of the development of methods for measuring emission rates from naturally ventilated livestock buildings over the last decade, 2) to identify and evaluate strengths and weaknesses, 3) to summarise and conclude the current state-of-art of available measurement concepts and their perspectives for improvement. The methods reviewed include determination of concentration and air exchange rate separately, tracer gas ratio, passive flux samplers, flux chambers, and combined downwind measurement and dispersion modelling. It is concluded that passive flux samplers, flux chambers and combined measurement and dispersion modelling are useful, but for limited fields of application only and require further development and validation against reference methods. The most robust method to investigate emission rates available at this stage is the tracer gas ratio method, but improvements are required. They include more detailed estimates of CO2 release rates (when using CO2 as a tracer) and research into optimising dosing performance of tracer gas release systems. The reliability of tracer gas ratio methods applied in buildings with large ventilation openings needs to be improved by a more profound understanding of tracer-pollutant ratios and their spatial variability, and the development of improved sampling methods for concentration ratios. There is a need for a field reference method against which other methods can be evaluated. None of the diicussed measurement methods can be marked as a solid reference for all conditions; tracer gas ratio methods are the most likely candidate but need further improvement. (C) 2012 IAgrE. Published by Elsevier Ltd. All rights reserved.The contribution to this paper of N. Ogink and J. Mosquera was financially supported by the Netherlands Ministry of Infrastructure and Environment.Ogink, NWM.; Mosquera, J.; Calvet Sanz, S.; Zhang, G. (2013). Methods for measuring gas emissions from naturally ventilated livestock buildings: Developments over the last decade and perspectives for improvement. Biosystems Engineering. 116(3):297-308. https://doi.org/10.1016/j.biosystemseng.2012.10.005S297308116

Soil eutrophication shaped the composition of pollinator assemblages during the past century

Atmospheric nitrogen deposition and other sources of environmental eutrophication have increased substantially over the past century worldwide, notwithstanding the recent declining trends in Europe. Despite the recognized susceptibility of plants to eutrophication, few studies evaluated how impacts propagate to consumers, such as pollinators. Here we aim to test if soil eutrophication contributes to the temporal dynamics of pollinators and their larval resources. We used a temporally and spatially explicit historical dataset with information on species occurrences to test if soil eutrophication, and more specifically nitrogen deposition, contributes to the patterns of change of plant and pollinator richness in the Netherlands over an 80 yr period. We focus on bees and butterflies, two groups for which we have good knowledge of larval resources that allowed us to define groups of species with different nitrogen related diet preferences. For each group we estimated richness changes between different 20‐yr periods at local, regional and national scale, using analytical methods developed for analyzing richness changes based on collection data. Our findings suggest that the impacts of soil eutrophication on plant communities propagate to higher trophic levels, but with a time‐lag. Pollinators with nitrogen‐related diet preferences were particularly affected, in turn potentially impairing the performance of pollinator‐dependent plants. Pollinator declines continued even after their focal plants started to recover. In addition, our results suggest that current levels of nitrogen deposition still have a negative impact on most groups here analyzed, constraining richness recoveries and accentuating declines. Our results indicate that the global increase in nitrogen availability plays an important role in the ongoing pollinator decline. Consequently, species tolerances to soil nitrogen levels should be considered across all trophic levels in management plans that aim to halt biodiversity loss and enhance ecosystems services worldwide

Preface paper to the Semi-Arid Land-Surface-Atmosphere (SALSA) Program special issue

The Semi-Arid Land-Surface-Atmosphere Program (SALSA) is a multi-agency, multi-national research effort that seeks to evaluate the consequences of natural and human-induced environmental change in semi-arid regions. The ultimate goal of SALSA is to advance scientific understanding of the semi-arid portion of the hydrosphere–biosphere interface in order to provide reliable information for environmental decision making. SALSA approaches this goal through a program of long-term, integrated observations, process research, modeling, assessment, and information management that is sustained by cooperation among scientists and information users. In this preface to the SALSA special issue, general program background information and the critical nature of semi-arid regions is presented. A brief description of the Upper San Pedro River Basin, the initial location for focused SALSA research follows. Several overarching research objectives under which much of the interdisciplinary research contained in the special issue was undertaken are discussed. Principal methods, primary research sites and data collection used by numerous investigators during 1997–1999 are then presented. Scientists from about 20 US, five European (four French and one Dutch), and three Mexican agencies and institutions have collaborated closely to make the research leading to this special issue a reality. The SALSA Program has served as a model of interagency cooperation by breaking new ground in the approach to large scale interdisciplinary science with relatively limited resources

Télédétection et gestion des ressources en eau, atelier international: 1. Programme et résumés, 2. Communications (recueil provisoire) = Remote sensing and water resources management, international workshop : 1. Program and abstracts, 2. Pre-proceedings

Les données de télédétection dans le visible et dans l'infrarouge thermique ont été largement utilisées pour estimer la distribution spatiale des composants du bilan d'énergie. L'approche la plus répandue, dite instantanée, consiste à estimer le rayonnemnet net, le flux de chaleur dans le sol et le flux de chaleur sensible à partir, d'une part, des données météorologiques récoltées sur le terrain, et d'autre part, des variables télédétectées : la température de surface, l'albédo et l'indice de végétation. L'évapotranspiration réelle est ensuite déduite comme étant le terme résiduel de l'équation du bilan d'énergie. La deuxième approche, dite dynamique, est basée sur l'utilisation d'un modèle de processus de type SVAT en conjonction avec un modèle de transfert radiatif et un schéma de minimisation numérique. Le principe de cette méthode consiste à forcer le modèle SVAT à restituer une signature spectrale de la surface en accord avec la mesure satellitaire. L'objectif de cette étude est de tester la performance de ces deux méthodes en utilisant des données récoltées sur des surfaces agricoles et sur des surfaces naturelles. Les avantages et les limites associés à chacune des deux approches sont discutés. (Résumé d'auteur