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Agricultural expansion has transformed and fragmented natural forest habitats at an alarming rate, and dramatic increases in agricultural intensification have since taken place in order to keep pace with human population growth and food demands. This simultaneously poses a considerable threat to biodiversity in agricultural landscapes, as production land is now one of the largest terrestrial biomes on the planet. Therefore, its contribution to biodiversity conservation is critical. Links between the intensification of agricultural systems and ‘in situ’ declines of biodiversity on farmland have been well documented. However, despite growing recognition that system inputs such as fertiliser and livestock can move or ‘spillover’ into adjacent natural habitats, there has been no direct quantification of the extent of impacts in recipient ecosystems. These abiotic and biotic pathways can cause dramatic impacts on the diversity, composition, and functioning of remaining natural ecosystems, and on their ability to provide a variety of essential ecosystem services. Due to concerns regarding future food security, balancing trade-offs between agriculture and conservation has subsequently become a hot topic in ecological research. However, without any direct quantification of the off-site ecological impacts of agricultural intensification in mosaic landscapes, it is inherently difficult to fully evaluate strategies aimed at balancing production and conservation. Using New Zealand farming systems as a case study, this thesis aims to address gaps in our current understanding of how increasing agricultural intensification impacts biodiversity in native forest remnants embedded within production landscapes. The first main chapter explores whether the magnitude of ecological impact in forest remnants (for a suite of 26 response measures) and severity of edge effects, scale with the degree of land-use intensity in surrounding agricultural pastures. This chapter also examines whether ecological responses differ in remnants ‘spared’ for conservation purposes (i.e. where livestock are excluded by fencing). The second chapter uses a model food-chain approach native to New Zealand, to test whether nutrient spillover from agricultural pastures influences plant-herbivore and herbivore-parasitoid interactions in forest remnants. This chapter also includes a large-scale common garden fertilisation experiment using the same tri-trophic system, which was established to examine bottom-up multi-trophic responses to the independent and combined effects of Nitrogen (N), Phosphorus (P) and cow dung and urine. The third main chapter uses a novel stable isotope approach for quantifying community-wide incorporation of resources into trophic structure. I test for the first time whether increasing intensity of farming systems drives greater nutrient spillover spatially into adjacent forest remnant soils and examine scaling effects of 15N (as a marker for anthropogenic N) through multiple trophic levels. Beyond finding that agricultural land-use intensity generally has negative off-site effects on biodiversity, the key findings of this thesis were (i) spillover of nitrogen and phosphorus from agricultural systems into adjacent remnant soils is exacerbated by increases in land-use intensity, with (ii) percolating bottom-up effects on plant and insect community dynamics. (iii) The magnitude of ecological impacts in forest remnants scales linearly with increasing land-use intensity, as does (iv) direct anthropogenic N enrichment across multiple trophic levels, which has the potential to severely jeopardise the stability of ecologically important remnant habitats. (v) Although there were stark structural differences in remnants with and without livestock exclusion, impacts of land-use intensity on ecological response metrics were actually comparable across all sites. (vi) Livestock exclusion should be a priority first step towards conserving native forest remnants, however it should be recognised that fencing does not prevent abiotic channels of nutrient spillover (fertiliser drift, overland flow, leaching) in land characteristic of land spared for nature. (vii) Consequently, increasing land-use intensity compromises the effectiveness of the land-sparing trajectory for conserving native biodiversity, which is currently undertaken in New Zealand production systems. Given the overall strength of these findings and the novel, ecosystem-wide and landscape-scale approaches taken to address fundamental questions, the work in this thesis greatly enhances our knowledge of the relationships between agricultural productivity and ecological impacts in spatially-coupled ecosystems. This is highly important, not only in New Zealand but worldwide, as it is anticipated that unstoppable human population growth and food security pressures will cause ecological impacts both on the farm and in adjacent natural ecosystems to become even more severe. Therefore, determining the relationship between land-use intensification and biodiversity loss represents the cornerstone of sustainable agricultural development in the future.

It has been argued that organic farming sustains a higher biodiversity than conventional farming. This might promote the ecosystem services that exist in agricultural landscapes such as pollination and pest control. Here, I examined the effect of farming system (organic vs. conventional) with respect to the time since farming system transition, landscape heterogeneity and plant richness on pollinating and predatory insects. In total, data from 30 farms were used, of which 20 were organic and 10 were conventional. The data were analyzed using general linear models and model averaging. The results show that insect groups responded differently to various factors. Pollinators were more sensitive to landscape complexity, showing an increase of abundance and species richness with an increased heterogeneity. Predators on the other hand reacted to farming system, where there was an increase in abundance and species richness on organic farms.

Les "déchets" organiques sont utilisés pour fertiliser les terres agricoles depuis l'avènement de l'agriculture. Longtemps considérés comme des ressources, les résidus organiques urbains ne deviennent des déchets qu'au début du 20ème siècle. Ils sont alors délaissés par le monde agricole et entassés dans des décharges. Aujourd'hui leur valorisation s'impose comme un des axes majeurs des politiques de gestion des déchets. En parallèle, l'agriculture cherche les voies d'une augmentation de la production qui soit respectueuse de l'environnement. A la croisée de ces deux problématiques, le programme de recherche ANR "ISARD", qui constitue à la fois le cadre et l'objet de cette étude, vise à une "Intensification écologique des Systèmes Agricoles par le Recyclage des Déchets". Différents "produits résiduaires organiques" sont ainsi appelés à devenir de véritables intrants agricoles, sûrs et efficaces, participant à l'intensification de l'agriculture. Leur intégration dans des dispositifs industriels de normalisation, leur conférant le statut de produit commercial, apparaît comme le moyen le plus adapté pour répondre à ces attentes. En suivant les enseignements des sociologies pragmatistes prenant en compte le rôle des objets dans l'action, c'est à la description des différentes formes sociotechniques de la valorisation agricole (ressource, déchet, produit) que se consacre ce travail. La prise en compte d'une pluralité de formes de valorisation permet d'insister sur les déplacements induits par une logique "produit" et les reconfigurations qu'elle provoque, notamment par rapport à la pluralité des mondes agricoles.

La coïncidence des services écosystémiques ainsi que la coïncidence entre 'hotspots' de servicesécosystémiques et 'hotspots' de biodiversité ont suscité un intérêt croissant dans les évaluations desservices écosystémiques. Les seuils utilisés dans ces analyses pour déterminer la présence desservices écosystémiques varient de façon importante mais les effets consécutifs à leur choix n'ontpas été envisagés. Nous proposons ici une analyse de l'effet du choix de ces seuils sur lacoïncidence entre services écosystémiques ainsi que sur la distribution des 'hotspots'. A partir d'uneétude de prairies des Alpes Centrales françaises, nous avons fait varié des seuils appliqués à troisservices écosystémiques (agronomique, de régulation et de valeur esthétique) de façon continue,puis considéré des triplets de valeurs-seuils représentant trois points de vue contrastés associés à despoints de vue d'acteurs. Ces seuils sont interprétés comme une importance accordée par chaqueacteur à chaque service écosystémique.La coïncidence entre services écosystémiques dépend de la détermination de seuils de présence.L'étendue des 'hotspots' de services écosystémiques et leur coïncidence avec les 'hotspots' debiodiversité varient largement selon les points de vue. Les coldspots ne sont jamais superposés avecles zones d'intérêt pour la biodiversité dans cette étude, quel que soit le point de vue envisagé.L'analyse de superposition s'est révélée moins informative que le test de diagnostic de la capacitéindividuelle des services écosystémiques à capturer la distribution des autres services. La valeuragronomique capturait peu les autres services écosystémiques. La biodiversité était bien capturéepar les valeurs esthétiques et de régulation, mais faiblement par les 'hotspots' de services.Cette analyse souligne l'importance de considérer les attentes variables des teneurs d'enjeux dans lesévaluations de 'hotspots' de services écosystémiques.

Process intensification tools, such as the capillary reactor, offer several benefits to the chemical process industries due to the well-defined high specific interfacial area available for heat and mass transfer, which increases the transfer rates, and due to low inventories, they also enhance the safety of the process. This has provided motivation to investigate three such tools, namely the capillary microreactor, spinning disc and rotating tube reactors, in this study. / The gas-liquid slug flow capillary microreactor intensifies reactor performance through internal circulation caused by the shear between the continuous phase/wall surface and the slug axis, which enhances the diffusivity and consequently increases the reaction rates. However, integrating the complex hydrodynamics of this reactor with its chemical kinetics is a mathematically challenging task. Therefore, in this study, a simple-to-complex approach, using a set of state-of-the-art computational fluid dynamic tools, has been used. Firstly, simulations were performed without any chemical reaction to ascertain the extent of slug flow regime. The model also clearly captured the slug flow generation mechanism which can be used to structurally optimize the angle of entry in these reactors. Finally, the hydrodynamic model was also capable of estimating the pressure drop and slug lengths. After successfully simulating the hydrodynamics of the system, a reaction model was incorporated to study the chemical reaction kinetics. The results were compared with the published experimental work and were found to be in good agreement. / The spinning disc reactor utilizes the centrifugal and shear forces to generate thin liquid films characterized with intense interfering waves. This enables a very high heat transfer coefficients to be realized between the disc and liquid, as well as very high mass transfer between the liquid and the bulk gas phase. The waves formed also produce an intense local mixing with very little back mixing. This makes a spinning disc reactor an ideal contactor for multiphase processes. The focus of this study has been to elucidate the hydrodynamic behaviour of the liquid film flow over the horizontal spinning disc. Investigations were also performed to elaborate the local and overall hydrodynamic characteristics of a fully developed spinning disc reactor. Simulation results showed a continuous linear liquid film on the horizontal spinning disc and intense mixing performance in the annulus of the reactor around the disc surface. Finally, the film thickness data from the simulations were compared with the limited amount of data available for this novel process. / Rotating tube reactor also uses centrifugal forces to generate the liquid film and a high degree of mixing along with an improved control over the reactant retention times. In this work we have conducted a CFD analysis to understand the hydrodynamics of this new technology for future developments.

A key challenge facing dairy farming is to meet the increasing demand for dairy products from a growing and more affluent global population in a period of unprecedented socio-economic and environmental change. In order to address this challenge, policies are currently placing emphasis on ‘sustainable intensification’ (SI), i.e. producing ‘more’ outputs and services with ‘less’ resources and environmental impacts. Determining whether or not SI can deliver greater yet sustainable dairy production requires understanding of the relationships between sustainability pillars (environmental; economic; and social) and farm aspects (e.g. on-farm management; and animal productivity) under particular farming systems and circumstances (e.g. regional bio-physical conditions). Trade-offs between pillars and aspects is inevitable within a farming system. Many widely-used assessment methods that aim to measure, scale and weight these pillars and aspects are unable to fully capture trade-offs between them. The objectives of this thesis are: 1) to identify key trade-offs in dairy farming systems to inform greater yet sustainable food production; and 2) to introduce models and methodologies aiming at a more holistic measurement and better understanding of dairy farm sustainability. This thesis assesses the sustainability of French and UK dairy farming systems via a farm efficiency benchmarking modelling framework coupled with statistical analyses. It explores the relationships between pillars, aspects and technical, economic and environmental performance; and identifies important drivers/differentials in dairy farm efficiency. Importantly, it also suggests ways in which farm inputs and outputs can be adjusted so that improvements in environmental, technical and economic performance become feasible. Efficiency benchmarking was performed with the multiple-input – multiple-output productive efficiency method Data Envelopment Analysis (DEA). DEA calculates single aggregated efficiency indices per farm by accounting for several farm inputs and outputs which the DEA model endogenously scales and weights. In this work, the notion of farm inputs and outputs was extended to also include ‘undesirable’ outputs (greenhouse gas emissions) and environmental impacts (e.g. eutrophication, acidification etc.) of dairy farming. The DEA models employed belong to the family of ‘additive’ models, which have several advantages over ‘traditional’ DEA models. These include their ability (i) to simultaneously increase outputs and reduce inputs, undesirable outputs and environmental impacts; (ii) to identify specific sources of inefficiency. These ‘sources’ represent a farm’s shortfalls in output production and its excesses in input use and/or in undesirable outputs and environmental impacts, relatively to the other farms; (iii) to position undesirable outputs in the output set rather than consider them as inputs or ‘inverse’ outputs; and (iv) to rank farms by efficiency performance. Importantly, this thesis also proposes a new additive model with a ranking property and high discriminatory power. In a second stage, DEA was coupled with partial least squares structural equation modelling (SEM) so as to develop and relate latent variables for environmental performance, animal productivity and on-farm management practices. The results suggested that the efficacy of SI may be compromised by several on-farm trade-offs between pillars, aspects and farm inputs and outputs. Moreover, trade-offs depended on particular farming systems and circumstances. Increasing animal productivity did not always improve farm environmental performance at whole farm-level. Intensifying production at animal and farm-levels, coupled with high reliance on external inputs, reduced farm environmental performance in the French case, i.e. a significant negative relationship was found between intensification and environmental performance (SEM path coefficients ranged between -0.31 and -0.57, p < 0.05). Conversely, in the UK case, systems representing animal-level intensification (via genetic selection) for increased milk fat plus protein production performed better, on average, than controls of UK average genetic merit for milk fat plus protein production in terms of technical efficiency (DEA scores between 0.91– 0.92 versus 0.78–0.79) and environmental efficiency (scores between 0.92–0.93 versus 0.80), regardless of whether on a low-forage or high-forage diet. The levels of inefficiency in (undesirable) outputs, inputs and environmental impacts varied among farming systems and depended on the regional and managerial characteristics of each system. For instance, in France, West farms had higher eutrophication inefficiencies than East farms (average normalized eutrophication inefficiencies were, respectively 0.141 and 0.107), perhaps because of their more intensive production practices. However, West farms were more DEA-efficient than East farms as the former benefited from bio-physical conditions more favourable to dairy farming (mean DEA score ranks were 97 for West and 83 for East). Such findings can guide policy incentives for SI in different regions or dairy systems. The proposed modelling framework significantly contributes to current knowledge and the search for the best pathways to SI, improves widely-used modelling approaches, and challenges earlier findings based on less holistic exercises.

Le but de l'étude présentée dans ce mémoire de thèse est de caractériser localement l'intensification des transferts thermiques observée le long d'une plaque chauffante lorsqu'elle est soumise à des ultrasons. Ces derniers induisent des effets hydrodynamique dans les fluides qu'ils traversent. Premièrement, la cavitation acoustique, qui permet de produire de forts effets mécaniques dans les liquides. Viens ensuite le courant acoustique qui génère une écoulement convectif sous l'action d'une dissipation visqueuse de l’énergie acoustique. Ce travaille à permis de mettre en évidence la relation existant entre ces effets hydrodynamiques et l'intensification des transferts thermiques observée. Ces résultats ont permis de définir quelles conditions expérimentales sont favorables à l'intégration d'ultrasons dans un échangeur de chaleur. / The aim of the study presented in this thesis is to characterize heat transfer enhancement by ultrasound observed along a hot plate in forced convection. These induced hydrodynamic effects in the fluids they cross. The first one is the acoustic cavitation, which can produce strong mechanical effects in liquids. The second one is the acoustic streaming which generates convective flows thanks to viscous dissipation of the acoustic energy. This work helped to highlight the relationship between ultrasound hydrodynamic effects and heat transfer enhancement. Thanks to those results, experimental conditions which allowed ultrasound integration in a heat exchangers, could be determined.

Základním faktorem ovlivňující chov prasat je reprodukce a její intenzita. Intenzitu reprodukce lze ovlivnit vnějšími a vnitřními faktory, které zvíře obklopují. Z vnějších faktorů se jedná o roční období, výživu a způsoby ustájení z vnitřních genetické dispozice, zdravotní stav, kondice a v neposlední řadě plemeno prasete. Velká pozornost je v moderních chovech věnována hygieně chovu, chovným podmínkám a kondici zvířat. Hygiena chovu a zdravotní stav zvířat je ukazatelem kvality chovu. Velikost vrhu, četnost vrhu a životnost selat vypovídá o kvalitě výživy, stimulaci říje a inseminaci.

O PISA é uma metodologia apresentada pelo MAPA para fomento e difusão de tecnologias de produção sustentável para propriedades rurais. Seus principais pilares são o uso de boas práticas de produção como o plantio direto, a diversificação e a rotação de culturas, a integração lavoura-pecuária. A hipótese desse estudo foi de que a aplicação da metodologia PISA é capaz de promover a intensificação sustentável da produção em sistemas leiteiros do RS. O estudo foi realizado nas Missões, nos municípios de Guarani das Missões, São Paulo das Missões, Santo Antônio das Missões, Pirapó e São Nicolau, localizados no noroeste do RS. Foram avaliadas 54 propriedades rurais que participaram do PISA e que tem a produção de leite como atividade principal. O Projeto teve início em dezembro de 2011 com a realização do diagnóstico da situação inicial de cada propriedade e se estendeu até novembro de 2014. As informações utilizadas para o presente trabalho foram capturadas em uma base de dados referente às entrevistas realizadas com os produtores no início do projeto, após o primeiro, segundo e terceiro ano, respectivamente. Os dados levantados referem-se às variáveis de produção, de ocupação do uso do solo e de manejo empregado pelos produtores, como número de vacas em lactação, média de produção por vaca, dieta ofertada, área de cada cultivo, formas de manejo das pastagens e sistemas de cultivo. A média da produção de leite diária teve um aumento significativo de 33,7% (P<0,001). O aumento da produção total de leite (L.propriedade-1.dia-1) foi relacionado ao aumento do número de vacas em lactação (P<0.001, R2=0.41), que ocorreu em 76% das propriedades. Foi observado incremento na produção de leite em 89% das propriedades avaliadas, houve modificação nas práticas utilizadas pelos produtores tanto no critério relacionado ao manejo do pasto como na forma de plantio das culturas, onde a grande maioria dos produtores (96,1%), passou a adotar o controle da altura como principal critério de manejo da pastagem. As ações de intervenção propostas pela metodologia PISA promoveram impactos positivos nas propriedades avaliadas. Os principais fatores determinantes dos aumentos produtivos foram a organização de uso das áreas e a adoção do método de pastoreio “rotatínuo”. A adoção da prática do plantio direto e do manejo adequado das pastagens constituíram as principais ferramentas utilizadas pelo PISA para promoção da qualidade dos ambientes de produção, conservação de recursos naturais e otimização do uso de nutrientes na interface solo-planta-animal. / The PISA program is a method from MAPA for promotion and diffusion of sustainable production technologies in rural area. This method lies on conservationist production technics like no-till, diversification and rotation of the crop or integrated crop-livestock systems. This study questions the success of the PISA program to promote sustainable intensification in dairy farm from the Rio Grande do Sul. We analysed data from 54 dairy farms situated that participate in the PISA program in the Missões region, North-Este of the state, including the city areas of Guarani das Missões, São Paulo das Missões, Santo Antônio das Missões, Pirapó e São Nicolau. The Project started in 2011 with a diagnostic of the initial situation of the farms and extended until November 2014. We based the present study on interviews and milk production reports conducted at the beginning of the study, two and three year later. Main variables refer to milk production (total, per head and number of animals in production), soil use (e.g. no-till vs. tillage, area for each cultivate, system of rotation) and resource management (e.g. pasture management, quantity of feed and silage offered). Between 2011 and 2014, milk mean daily production increased in 89% of the farms resulting in a significantly mean increased of 33,7% (P<0.001). This increase was significantly related to an increase in the number of dairy cattle (P<0.001, R2=0.41) that occurred in 76% of the farms. Farmers significantly change their management practices. No-till management increasing from 19 to over 70% of the cultivated areas, and grazing management based on sward height increase from one third to 96,1%. The PISA program, by successfully implementing sustainable management practices, resulted in highly significant positive result regarding milk productivity. Main practices that resulted in this success were no-till practices, a better organisation in the use of the area and rigorous grazing management based on low intensity/high frequency rotational grazing (i.e. “rotatíno"). Through these changes in management practices, the PISA program promoted more sustainable and more productive farm systems, better conservation of soil natural resources and optimisation of nutrient uses at the soil-plant-animal interface.