European floodplain grasslands are characterized by periodic flooding and regular management, usually cutting and grazing as part of an agricultural system. Past losses and ecological degradation have been due largely to river regulation and either agricultural intensification or abandonment and have resulted in a substantial reduction in area across Europe. Nevertheless, the remaining resource supports considerable biodiversity and a high level of biological production. A better quantitative understanding of the functioning of these grasslands is required in order to establish effective conservation management within a sustainable land use system. The thesis examines the impact of key management factors on three important functional characteristics of the biodiversity of floodplain plant communities, namely plant diversity (measured by species diversity), cover (%) and primary production (above-ground biomass), on two floodplain grasslands of the River Trent, UK and a third on the the Luznice river, the Czech Republic. Field investigations of the effects of cutting, grazing, cessation of management, the influence of floodborne litter, and the impact of fertilizer nitrogen were undertaken over periods of between one and three seasons. These demonstrated that floodplain grassland plant communities are sensitive to variations in management and that impacts on communities are mediated particularly through effects on plant competition. Productive competitive species were encouraged both by abandonment and fertilizer application whereas cutting and grazing management, and the imposition of litter, favoured stress-tolerating perennials. Species diversity decreased both with high inputs of litter and additions of fertilizer. Plant community responses and competitive strategies of key species are discussed in the context of biodiversity conservation, ecological restoration and management of European floodplain grasslands.

No description available.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2006. / Härtill 4 uppsatser.

Made available in DSpace on 2014-06-11T19:33:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-01-22Bitstream added on 2014-06-13T19:23:34Z : No. of bitstreams: 1 oliveira_ap_dr_jabo.pdf: 2622514 bytes, checksum: 94a4f867dbbcfbd202c95a288eebe391 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente trabalho teve como objetivos avaliar diferentes estratégias para terminação de novilhas. No período de transição águas-secas, avaliou-se o desempenho de novilhas submetidas à pastejo contínuo com diferentes ofertas de forragem associada ao fornecimento de suplementos. O segundo experimento teve como objetivo avaliar os efeitos da suplementação durante o período seco sobre o desempenho de novilhas mantidas em pastagem diferida nas águas. E no terceiro estudo objetivou-se avaliar o desempenho de novilhas em confinamento recebendo dietas com duas relações volumoso:concentrado contendo monensina sódica (MS) ou bicarbonato de sódio (BS) com vistas a avaliar sistemas de produção de fêmeas jovens para abate. No experimento de águas, o delineamento utilizado foi o de blocos casualizados, com 2 repetições, num fatorial 3 x 2 (três ofertas de forragem 1,5; 2,0 e 2,5 kg de MVS/kg PC, e dois níveis de suplementação (0,0 e 0,3% PC). Foi observada diferença significativa entre as ofertas de forragem, sendo que a de 2,5 kg de MVS/kg de PV possibilitou o maior GPD (0.605 kg/animal/dia). A SP da dieta de novilhas de corte com 0,3% do PV permite GPV adicional superiores a 200 g/dia. No experimento de seca o delineamento utilizado foi o de blocos casualizados, com 8 repetições, num fatorial 2 x 2, com medidas repetidas no tempo. Os tratamentos de seca foram definidos considerando as 2 quantidades de suplementos fornecidos no período da águas, combinando com 2 quantidades e teores de proteína (0,4% do PC com 25,3% de PB; 0,2% do PC com 52,1% PB). A suplementação com 0,4 e 0,2% propiciou GP relativamente altos (0,431 kg/dia e 0,268 kg/dia), respectivamente. O GP dos animais esteve diretamente relacionado com a oferta de folhas verdes. No experimento de confinamento foram testadas dietas com 50% e 80% de concentrado, com adição de MS ou BS. A alta inclusão de grãos... / This study aimed to evaluate different strategies for finishing heifers in pasture and feedlot system. In the first experiment, the heifers performance was evaluated during the wet to dry season period in a continues stocking grazing system with different forage allowance associated to supplementation. The second experiment was conducted to evaluate supplementation during the dry season on the heifers performance kept in a pasture stockpiled at the end of the wet season. In the third study evaluate the performance of feedlot heifers fed diets with two different roughage: concentrate ratios, containing monensin (MS) or sodium bicarbonate (BS) in order to evaluate the production systems of young females for slaughter. The wet season experiment was conducted according a randomized block design in a factorial 3 x 2 (three forage allowance levels 1.5, 2.0 and 2.5 kg of DM/ kg BW, and two supplementation levels (0.0 and 0.3% BW) with two replications (pastures) Significant difference between forage allowance was observed. The highest forage allowance (2.5 kg of DM/kg BW) resulted in highest average daily gain (ADG 0.605 kg/animal / day). Beef heifers supplementation with 0.3% BW allows additional ADG of the 200 g/ day. In the dry season experiment the design was a randomized block with eight replicates (heifers) in a 2 x 2 factorial, with repeated measures over time. The dry season treatments were arranged considering the two quantities of supplement provided during the wet period, combining with two quantities of supplement and protein content (0.4% BW with 25.3% CP, 0.2% of the PC 52, 1% CP). Supplementation with 0.4 and 0.2% BW resulted in relatively high daily weight gain (0.431 and 0.268 kg/ day), respectively. The animals ADG were directly related to the green leaves allowance. In the feed lot experiment were evaluated diets with 50% and 80% of concentrate, associated with sodium ... (Complete abstract click electronic access below)

Resumo: O presente trabalho teve como objetivos avaliar diferentes estratégias para terminação de novilhas. No período de transição águas-secas, avaliou-se o desempenho de novilhas submetidas à pastejo contínuo com diferentes ofertas de forragem associada ao fornecimento de suplementos. O segundo experimento teve como objetivo avaliar os efeitos da suplementação durante o período seco sobre o desempenho de novilhas mantidas em pastagem diferida nas águas. E no terceiro estudo objetivou-se avaliar o desempenho de novilhas em confinamento recebendo dietas com duas relações volumoso:concentrado contendo monensina sódica (MS) ou bicarbonato de sódio (BS) com vistas a avaliar sistemas de produção de fêmeas jovens para abate. No experimento de águas, o delineamento utilizado foi o de blocos casualizados, com 2 repetições, num fatorial 3 x 2 (três ofertas de forragem 1,5; 2,0 e 2,5 kg de MVS/kg PC, e dois níveis de suplementação (0,0 e 0,3% PC). Foi observada diferença significativa entre as ofertas de forragem, sendo que a de 2,5 kg de MVS/kg de PV possibilitou o maior GPD (0.605 kg/animal/dia). A SP da dieta de novilhas de corte com 0,3% do PV permite GPV adicional superiores a 200 g/dia. No experimento de seca o delineamento utilizado foi o de blocos casualizados, com 8 repetições, num fatorial 2 x 2, com medidas repetidas no tempo. Os tratamentos de seca foram definidos considerando as 2 quantidades de suplementos fornecidos no período da águas, combinando com 2 quantidades e teores de proteína (0,4% do PC com 25,3% de PB; 0,2% do PC com 52,1% PB). A suplementação com 0,4 e 0,2% propiciou GP relativamente altos (0,431 kg/dia e 0,268 kg/dia), respectivamente. O GP dos animais esteve diretamente relacionado com a oferta de folhas verdes. No experimento de confinamento foram testadas dietas com 50% e 80% de concentrado, com adição de MS ou BS. A alta inclusão de grãos ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This study aimed to evaluate different strategies for finishing heifers in pasture and feedlot system. In the first experiment, the heifers performance was evaluated during the wet to dry season period in a continues stocking grazing system with different forage allowance associated to supplementation. The second experiment was conducted to evaluate supplementation during the dry season on the heifers performance kept in a pasture stockpiled at the end of the wet season. In the third study evaluate the performance of feedlot heifers fed diets with two different roughage: concentrate ratios, containing monensin (MS) or sodium bicarbonate (BS) in order to evaluate the production systems of young females for slaughter. The wet season experiment was conducted according a randomized block design in a factorial 3 x 2 (three forage allowance levels 1.5, 2.0 and 2.5 kg of DM/ kg BW, and two supplementation levels (0.0 and 0.3% BW) with two replications (pastures) Significant difference between forage allowance was observed. The highest forage allowance (2.5 kg of DM/kg BW) resulted in highest average daily gain (ADG 0.605 kg/animal / day). Beef heifers supplementation with 0.3% BW allows additional ADG of the 200 g/ day. In the dry season experiment the design was a randomized block with eight replicates (heifers) in a 2 x 2 factorial, with repeated measures over time. The dry season treatments were arranged considering the two quantities of supplement provided during the wet period, combining with two quantities of supplement and protein content (0.4% BW with 25.3% CP, 0.2% of the PC 52, 1% CP). Supplementation with 0.4 and 0.2% BW resulted in relatively high daily weight gain (0.431 and 0.268 kg/ day), respectively. The animals ADG were directly related to the green leaves allowance. In the feed lot experiment were evaluated diets with 50% and 80% of concentrate, associated with sodium ... (Complete abstract click electronic access below) / Orientador: Ricardo Andrade Reis / Coorientador: Telma Teresinha Berchielli / Banca: Valdo Rodrigues Herling / Banca: Marco Antonio Alvares Balsalobre / Banca: Flávio Dutra de Resende / Banca: Alexandre Amstalden Moraes Sampaio / Doutor

Diss. (sammanfattning) Skara : Sveriges lantbruksuniv., 2007. / Härtill 5 uppsatser.

Le concept de services écosystémiques est de plus en plus utilisé par différentes disciplines scientifiques et pris en compte dans les sphères politiques pour attirer l'attention sur les bénéfices que l'Homme reçoit des écosystèmes. Ce concept mène à étudier les liens complexes entre l'homme et son environnement. Cependant, la majorité des recherches actuelles restent théorique et peu de cas d'étude mettent à l'épreuve ce concept dans une démarche transdisciplinaire. Cette thèse à donc pour objectif principal de combler ce manque en explorant et analysant les dynamiques et processus des services écosystémiques en terme d'offre et de demande, y compris les effets de rétroactions, par une approche socio-écologique dans un contexte de changement planétaire. A cette fin, une étude transdisciplinaire a été conduite sur les prairies subalpines de la commune de Villar d'Arène (Hautes-Alpes) où l'élevage ovin et bovin domine. Des techniques de modélisations statistiques et de systèmes d'informations géographiques ont été combinées pour analyser la fourniture potentielle de services écosystémiques, conduisant à une cartographie de ceux-ci à l'échelle du paysage. La demande en services écosystémiques à quant à elle été étudiée par l'intermédiaire d'entretiens individuels et de groupes avec les acteurs locaux ainsi que des jeux de rôle avec les éleveurs de la commune. La co-construction de scénarios prospectifs avec les acteurs locaux ont permis d'étudier l'évolution de l'offre et la demande en services à un horizon 2030. / The ecosystem service (ES) concept is increasingly used in different scientific disciplines and is spreading into policy and business circles to draw attention to the benefits that people receive from biodiversity and ecosystems. Nevertheless, while the number of case studies considering various dimensions of the interactions between ecosystems and land use via ES has been steadily increasing, integrated research addressing interrelationships between biodiversity, ES and land use has remained mostly theoretical. This thesis aims through a socio-ecological approach to understand: (1) Which ES are potentially delivered given ecological dynamics, (2) how these ES are perceived by stakeholders in terms of value and knowledge, (3) how human management affects ES delivery, and (4) how ES are taken into account in land management decisions, thereby considering feedbacks from ecosystem to the land use system through ES. To address these questions, an interdisciplinary study was conducted on Villar d'Arène (French Alps) a municipality where the subalpine landscape is shaped by extensive mountain livestock farming. Statistical modelling and geographical information systems where combined to analyse the determinants of the spatial distribution of biodiversity and ES within the landscape using ecological (including plant functional traits), biophysical and land-use data. The following ES were mapped: agronomic value, aesthetic value, water quality, carbon storage, soil fertility, soil moisture, conservation of plant diversity and pollination. These allowed us to quantify trade-offs and synergies in the current landscape and to identify key management types supporting multifunctionality. The dynamics of ES was projected under four different scenarios integrating climatic, socio-economic and land-use changes, which were developed using a participative approach with regional experts and local farmers. Analyses of projected scenario impacts showed that ES synergies and trade-offs evolve differently when considering direct effects of climate on ecosystems, and/or their indirect effects through farmers adaptive responses. Interviews with local stakeholders (experts from nature conservation and agricultural extension, farmers and inhabitants) of mountain grasslands showed that the ES concept is still relatively unknown in explicit terms. Nevertheless after defining ES to interviewees, they expressed a variety of relevant interests and knowledge. Although all stakeholders valued a common set of ecosystem services (agronomic value, aesthetic value, water quality, and conservation of plant diversity), we identified negative and positive representations of the effects of grassland management on ecosystem services, depending on stakeholders perceptions of the relationships between soil fertility and biodiversity, and biodiversity and the other services. Finally, a role-playing game explored how ES cognition mediated environmental feedbacks on farmers' behaviours. Results emphasized the influence of other factors such as socio-economic or climatic context, topographic constraints, social value of farming or farmer individual and household characteristics, on the link between ES and land-management decisions. This case study demonstrates the interest of an integrated approach decomposing the feedback loop from ecosystems to land use when studying ES for scientific or policy purposes.

Les écosystèmes prairiaux alpestres sont supposés être très sensibles au changement climatique. Cependant leur long historique fait de variation du climat et de multiples siècles d'utilisation des terres peut avoir sélectionné des mécanismes de résilience écologique à la variabilité climatique et aux stress climatiques extrêmes. Nous avons utilisé un dispositif expérimental de grande envergure pour explorer les mécanismes de réponses des prairies subalpines à une combinaison d’extrêmes météorologiques hivernaux (fonte des neiges précoce) et estivaux (sécheresse) en fonction de la composition fonctionnelle des communautés végétales et des pratiques de gestion des terres. La composition fonctionnelle des prairies a été manipulée à l’aide d’assemblages de trois espèces de poacées en différentes abondances relatives, représentant in fine un gradient d’utilisation des ressources allant de la conservation à l'exploitation. De manière générale, la composition fonctionnelle a été le principal déterminant de tous les paramètres observés pour la performance individuelle des plantes, les réponses intraspécifiques des plantes, la décomposition de la litière et les processus de recyclage de l'azote. Le fonctionnement des écosystèmes prairiaux dominés par des plantes conservatrices a été remarquablement résistant aux traitements climatiques extrêmes, tandis que les écosystèmes prairiaux dominés par des plantes plus exploitatrices ont été plus résilients. Les pratiques de gestion ont modulé ces réponses et plus particulièrement dans le cas des communautés exploitatrices. Les allocations souterraines aux réserves glucidiques et aux pools d'azote microbiens ont été identifiées comme deux mécanismes clés sous-tendant les réponses des communautés résilientes. Néanmoins, des répercussions à plus long terme du changement climatique pourraient être observées, causées par un épuisement successif des réserves végétales et une diminution des retours azotés vers le sol via les processus de décomposition. / Alpine grassland ecosystems are presumed to be highly sensitive to climate change, yet their long history of climate variability, and multiple centuries of land use may have selected for mechanisms of ecological resilience to climate variability and climate extremes. We used a large experimental design to explore patterns and mechanisms for responses of subalpine grasslands to combined winter (snow removal) and summer (drought) weather extremes depending on plant functional composition and management. Plant functional composition was manipulated by establishing grass mixtures with three species representing a conservation to exploitation gradient planted at varying relative abundances. Overall, functional composition was the primary determinant of all observed parameters for plant individual performance, intraspecific plant trait responses, litter decomposition and nitrogen recycling processes. The functioning of grassland ecosystems dominated by conservative plants was remarkably resistant to extreme weather treatments, while grassland ecosystems dominated by more exploitative plants were more resilient. Management altered these responses mostly in the case of exploitative communities. Belowground allocation to carbohydrate reserves and to microbial nitrogen pools were identified as two key mechanisms underpinning these resilient responses. Longer-term impacts of climate change may however unfold through the exhaustion of plant reserves and decreasing nitrogen returns to soils via decomposition process.

No description available.