303 resultados para Farmland


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1. Identifying landscape patterns that allow native fauna to coexist with human land use is a global challenge. Riparian vegetation often persists in anthropogenic environments as strips of natural or semi-natural vegetation that provide habitat for many terrestrial species. Its relative contribution to landscape-scale conservation is likely to change as environments become increasingly modified. We used a ‘whole of landscape’ approach to test the hypothesis that riparian vegetation offers disproportionate benefits, relative to non-riparian vegetation, for the conservation of woodland birds in highly modified agricultural landscapes. 2. We selected 24 landscapes, each 100 km2, along a gradient of landscape change represented by decreasing cover of native vegetation (from 60% to <2%), in an agricultural region in SE Australia. Bird species were systematically surveyed at three riparian and seven non-riparian sites in wooded vegetation in each landscape. 3. Riparian sites supported a greater richness of woodland-dependent species, a group of conservation concern, than did non-riparian sites. The composition of assemblages also differed between site types. 4. At the landscape scale, the pooled richness of bird assemblages at riparian and non-riparian sites, respectively, decreased with overall loss of tree cover despite constant sampling effort. Within landscapes, the β-diversity of woodland species among non-riparian sites increased (composition became less similar) as landscape tree cover declined. In contrast, riparian assemblages were relatively stable with no change in β-diversity. Importantly, as landscape tree cover declined, the proportion of woodland species uniquely present at riparian sites increased and made a greater contribution to overall landscape diversity. 5. Synthesis and applications. Landscape-scale richness of woodland species declines as landscape tree cover is lost. In highly depleted landscapes, riparian vegetation retains a relatively rich, stable assemblage compared with that in heterogeneous remnants of non-riparian vegetation and consequently contributes disproportionately to landscape-scale diversity. These observations, together with the diverse benefits of riparian vegetation for aquatic ecosystems, mean that protection and restoration of riparian vegetation is a high priority in anthropogenic environments. Importantly, such actions are directly amenable to individual land managers, and the benefits will accumulate to enhance the persistence and conservation of species at landscape and regional scales.

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Following landscape change, species invasions and extinctions may lead to biotic homogenisation, resulting in increased taxonomic and functional similarity between previously distinct biotas. Biotic homogenisation is more likely to occur in landscapes where the matrix contrasts strongly with native vegetation patches. To test this, we examined the distribution of ground-active beetles in a landscape of remnant Eucalyptus open woodland patches where large areas of lower contrast matrix (farmland) are being transformed to high-contrast pine plantations in south-eastern Australia. We sampled beetles from 30 sites including six replicates of five categories; (1) remnants adjacent to farmland, (2) remnants adjacent to plantation, (3) farmland, (4) plantation, and, (5) remnants between pine plantation and farmland. Community composition in the pine matrix was similar to native patches embedded in pine (ANOSIM, Global R=. 0.49, P<. 0.000), which we suggest is due to biotic homogenisation. Remnant patches with edges of both farmland and pine plantation did not represent an intermediate community composition between patches surrounded by either matrix type, but rather a unique habitat with unique species. Farmland supported the greatest number of individuals (. F=. 9.049, df. =. 25, P<. 0.000) and species (. F=. 5.875, df. =. 25, P=. 0.002), even compared to native remnant patches. Our results suggest that matrix transformations can reduce species richness and homogenise within-patch populations. This may increase the risk of species declines in fragmented landscapes where plantations are not only replacing native vegetation patches, but also other matrix types that may better support biodiversity. Our findings are particularly concerning given expanding plantation establishment worldwide.

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Este trabalho tem como objetivo construir um referencial teórico que auxilie no entendimento de como a Agroenergia poderá impactar o mercado de terras no Brasil. Posteriormente, analisar os reflexos desta nova conjuntura no coeficiente de elasticidade de uso da terra, para a cultura da cana-de-açúcar, no Estado de São Paulo, após a introdução dos veículos flex-fuel no mercado brasileiro. Os aspectos relacionados ao mercado de terras, suas definições e características de uso, têm sido objeto de estudo de muitos pensadores e economistas, desde o final do século XIX. Motivado por esta afirmação, procurou-se realizar uma revisão de literatura para entender as diferentes linhas do pensamento econômico em relação às principais variáveis que compõem a formação de preço e a dinâmica do mercado de terras. Segundo a teoria neoclássica, o valor da terra está intrinsecamente associado à sua capacidade de produção. Aliado a esta característica, também é fundamental entender os atributos da terra como ativo real, seja na expectativa de ganhos de capital ou reserva de valor. Com o intuito de contribuir para esta discussão, foi proposto um fluxograma, que identificou como as variáveis deveriam se correlacionar e impactar na formação do preço das terras agrícolas. É possível afirmar que, no curto prazo, a Agroenergia impactará o valor das terras agrícolas, via preço das commodities, características de ativo real, especialmente na aposta de ganhos de capital e devido ao aumento das políticas governamentais relacionados à produção de biocombustíveis. Em relação ao coeficiente de elasticidade da área de cana-de-açúcar, em São Paulo, em relação a expectativa de preço da tonelada equivalente de ATR, para o açúcar e o etanol, observou-se que a cultura de cana-de-açúcar se tornou mais sensível às variações no preço da tonelada de ATR, expandindo a área cultivada com uma menor variação na expectativa de preço, após a introdução dos veículos flex-fuel no mercado nacional.

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The scarcity of farmland, reducing the supply of irrigation water and lack of technologies for conservation, makes the globalized world facing serious difficulties in the production of food for its population. The most viable outlet for this dilemma is the dissemination of technologies, economically viable and available to the whole population, for dehydration of perishable foods produced. This paper presents a solar dryer of direct exposure to the production of dried fruit, made from recycled polyethylene drum of 200 liters, used for storing water or trash. The drum was sectioned in half in its longitudinal axis and has its halves together forming a trough-like structure. It describes the processes of construction and assembly of solar dryer proposed, whose main characteristic its low cost, and was designed for use by people with low income, for processing fruits widely available in our region (mango, banana, guava, cashew, pineapple, tomato and others) in dried fruit and flour, contributing significantly to increase the life of these foods. The nuts and flours can be used for own consumption and for marketing jobs and income generation. Tests were conducted to diagnose the feasibility of using solar dryer for the various types of tropical fruits. Were also compared parameters such as drying times and thermal efficiency obtained with the prototype found in the specialized literature in food dehydration. The drying times in the dryer were obtained competitive with those obtained in other models of dryers LMHES developed

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Pós-graduação em Agronomia (Energia na Agricultura) - FCA

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The agricultural lands of this country are its greatest natural resource. History points out that nations with vast areas of good farm land are most likely to prosper and survive over long periods of time. Local communities, too, prosper and flourish in proportion to the productiveness of the surrounding land. Schools, social life, and business develop best in areas where the land is productive and properly managed and conserved. Nebraska, in common with other states, has suffered by the depletion of soil fertility. The reduction in acres in legumes and grasses, and the deplation of the organic matter in the surface soils, has likewise had its effect on the run-off of precipitation, soil blowing, and damage from drouth. In order to know what elements of fertility may become deficient and how soil fertility may be restored and maintained, we should understand the composition, character, and management of soils. In the following pages, some fundamentals of soil feritlity are given, followed later by a discussion of practical soil-management practices.

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Die Fragmentierung von Waldgebieten, der Verlust geeigneter Habitate, die Invasion exotischer Arten und globale Klimaveränderung haben auf Artengemeinschaften erhebliche Auswirkungen. Vögel dienen in vielen Fällen als Indikatorarten für Umweltveränderungen und, besonders, für Veränderungen im Zusammenhang mit globaler Erwärmung. In meiner Arbeit habe ich zuerst einen Literaturüberblick über die Auswirkungen globaler Klimaveränderung auf die Verbreitungsgebiete, den Artenreichtum und die Zusammensetzung von Vogelgemeinschaften dargestellt. Zahlreiche Untersuchungen zeigen, daß die Grenzen der Verbreitungsgebiete der meisten Vogelarten mit klimatischen Faktoren korrelieren. Verschiebungen der Verbreitungsgebiete in nördliche Richtung oder in höhere Regionen im Gebirge konnten bereits für viele temperate Vogelarten beobachtet werden. Weiterhin wurde ein zunehmender Artenreichtum besonders in nördlichen Breiten und in höheren Lagen für viele temperate Vogelgemeinschaften vorhergesagt. In trockenen Gebieten ist dagegen mit einer Abnahme des Artenreichtums zu rechnen. Im zweiten Teil meiner Arbeit habe ich untersucht, ob beobachtete Veränderungen in der Zusammensetzung europäischer Vogelgemeinschaften tatsächlich durch aktuelle Klimaveränderungen beeinflußt werden. Das Zugverhalten der Arten war dabei ein Schwerpunkt der Untersuchung, weil zu erwarten war, daß Vogelarten mit verschiedenem Zugverhalten unterschiedlich auf Klimaveränderungen reagieren. Ich habe ein Regressionsmodell genutzt, welches die räumliche Beziehung zwischen dem Anteil von Langstreckenziehern, Kurzstreckenziehern und Standvögeln in europäischen Vogelgemeinschaften und verschiedenen Klimavariablen beschreibt. Für 21 Gebiete in Europa habe ich Daten über beobachtete Veränderungen in der Struktur der Vogelgemeinschaften und isochrone Klimaveränderungen zusammengetragen. Mit Hilfe dieser Klimaveränderungen und dem räumlichen Regressionsmodell konnte ich berechnen, welche Veränderungen in den Vogelgemeinschaften aufgrund der veränderten Klimabedingungen zu erwarten wären und sie mit beobachteten Veränderungen vergleichen. Beobachtete und berechnete Veränderungen korrelierten signifikant miteinander. Die beobachteten Veränderungen konnten nicht durch räumliche Autokorrelationseffekte oder durch alternative Faktoren, wie z.B. Veränderungen in der Landnutzung, erklärt werden. Im dritten Teil der Arbeit untersuchte ich für eine mitteleuropäische Vogelgemeinschaft welchen Einfluß Habitatveränderungen, die Invasion exotischer Arten und die Klimaveränderung auf Veränderungen der Häufigkeit und Verbreitungsgröße der 159 Vogelarten am Bodensee zwischen 1980-1981 und 2000-2002 hatten. Dabei konnte gezeigt werden, daß Veränderungen in der regionalen Abundanz sowohl durch Habitatveränderungen als auch durch Klimavänderungen hervorgerufen wurden. Exotische Arten schienen in dieser Zeit keinen bedeutenden Einfluß zu haben. Besonders bei Agrarlandarten, Arten mit nördlicheren Verbreitungsgebieten und bei Langstreckenziehern konnten signifikante Abnahmen in der Abundanz beobachtet werden. Vor allem die anhaltenden negativen Bestandsveränderungen bei Langstreckenziehern und die in den letzten zehn Jahren aufgetretenen Abnahmen nördlicher verbreiteter Vogelarten deuten darauf hin, daß die Klimaveränderung aktuell als der größte Einfluß für Vögel in Europa angesehen werden muß. Insgesamt zeigen die Ergebnisse dieser Arbeit, daß sich der anhaltende Druck auf die Umwelt in erster Linie durch Habitat- und Klimaveränderungen manifestiert.

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Nel Comune di Ravenna, oltre 6.800 ettari di terreni agricoli sono a rischio salinizzazione, a causa dell’alta salinità delle acque sotterranee presenti all’interno dell’acquifero freatico costiero. L'area è interessata da subsidenza naturale, per compattazione dei sedimenti alluvionali e antropica, causata dall’estrazione di gas e dall’eccessivo sfruttamento delle acque sotterranee. Ne deriva che la maggior parte di questo territorio è sotto il livello medio del mare e l'agricoltura, così come ogni altra attività umana, è possibile grazie ad una fitta rete di canali di drenaggio che garantiscono il franco di coltivazione. L’agricoltura è una risorsa importante per la zona, ma a causa della scarsa disponibilità di acque dolci e per l’aumento dei processi di salinizzazione dei suoli, necessita di un cambiamento. Servono pratiche agricole sostenibili, con idonei requisiti irrigui, di drenaggio del suolo, di resistenza alla salinizzazione e di controllo del suolo. Dopo un’analisi generale sulle condizioni dell’acquifero, è stato monitorato un transetto di 10km rappresentativo della parte costiera di Ravenna. Infine, con l'obiettivo di comprendere l'interazione tra un canale d'irrigazione e le acque sotterranee, una piccola area agricola (12 ettari), è stata monitorata nel corso del 2011 utilizzando metodi idrologici, geochimici e geofisici. I risultati di questo lavoro mostrano una diffusa salinizzazione della falda freatica, ma anche la presenza di una lente d'acqua dolce spessa 5m, a 400m dalla linea di riva, con caratteristiche chimiche (hydrofacies) tipici di acque continentali e con dimensioni variabili stagionalmente. Questa bolla di acqua dolce si è originata esclusivamente dalle infiltrazioni dal canale d’irrigazione presente, in quanto, il contributo dell’irrigazione superficiale è stato nullo. Sfruttando la rete di canali di drenaggio già presente sarebbe possibile estendere questo processo d’infiltrazione da canale in altre porzioni dell’acquifero allo scopo di ricaricare l’acquifero stesso e limitare la salinizzazione dei suoli.

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Der Suche nach neuen Wirkstoffen für den chemischen Pflanzenschutz kommt insbesondere vor dem Hintergrund der steigenden Weltbevölkerung und weniger zur Verfügung stehenden kulturfähigen Ackerflächen eine stetig wachsende Bedeutung zu. Ziel dieser Arbeit war die Synthese von cyclischen Peptiden und Depsipeptiden, die aufgrund ihrer biologischen Aktivität als potentielle Insektizide für den chemischen Pflanzenschutz in Frage kommen. Darüber hinaus sollten von Kohlenhydraten abgeleitete Katalysatoren zur enantioselektiven Cyanhydrinsynthese entwickelt werden, um einen leichten Zugang zu den Bausteinen der Depsipeptide zu ermöglichen. Als vielversprechender Naturstoff mit insektiziden Eigenschaften gilt das cyclische Pentapeptid Cycloaspeptid E, dessen Totalsynthese in 10 Stufen mit einer Gesamtausbeute von 25% erreicht wurde, sodass die Verbindung für biologische Tests bereitgestellt werden konnte. Zusätzlich gelang die Kristallisation der Verbindung, was eine Röntgenstrukturanalyse ermöglichte. Ein Derivat von Cycloaspeptid E sollte 2-Aminonicotinsäure anstelle von Anthranilsäure enthalten. Die Synthese dieser Verbindung wurde auf drei Wegen versucht. Dabei zeigte sich, dass es bei einer zur Totalsynthese des Naturstoffs analogen Strategie zur quantitativen Bildung eines Diketopiperazins kommt. Auf den anderen Routen ließ sich entweder ein Kupplungsschritt nicht realisieren, oder die Verbindung erwies sich unter den gewählten Bedingungen als instabil. Die Darstellung eines 2-Aminonicotinsäure-Derivats von Cycloaspeptid E bleibt daher weiterhin ein ungelöstes Problem, das weiterer Forschung bedarf. Verticilid A1 ist ein cyclisches Depsipeptid, das aufgrund seiner Bindungsfähigkeit an den Ryanodinrezeptor von Insekten, als Leitstruktur für die Suche nach neuen Insektiziden von Interesse ist. Um zu untersuchen, wie wichtig die Esterbindungen im Molekül für die biologische Aktivität sind, sollte das entsprechende Amid-Derivat und das Cyclodepsipeptid mit nur zwei statt vier Esterbindungen hergestellt werden. Hierbei zeigte sich, dass eine zur Darstellung von Verticilid A1 analoge Syntheseroute zu einer ausgeprägten Epimerisierung führt. Eine lineare Synthese der Derivate endet in der Bildung des Diketopiperazins. Weiterhin wurden zwei neue, zueinander pseudoenantiomere Vanadium(IV)-Katalysatoren auf Basis von D-Glucose einerseits und L-Xylose andererseits dargestellt. Diese lassen sich in fünf bzw. 14 Stufen synthetisieren und liefern in der enantioselektiven Katalyse von Mandelsäurenitril Enantiomerenüberschüsse von 89% bzw. 91% bei hohen Ausbeuten. Zusammenfassend lässt sich feststellen, dass im Rahmen dieser Arbeit die Totalsynthese von Cycloaspeptid E erfolgreich durchgeführt wurde, und die Syntheseversuche von weiteren cyclischen Peptiden wichtige Erkenntnisse für weitere Synthesen lieferten. Mit den beiden hergestellten Vanadium(IV)-Komplexen wurden zwei potente, auf Kohlenhydraten basierende Katalysatoren für die enantioselektive Synthese von Cyanhydrinen entwickelt.

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It is a globally important challenge to meet increasing demands for resources and, at the same time, protect biodiversity and ecosystem services. Farming is usually regarded as a major threat to biodiversity due to its expansion into natural areas. We compared biodiversity of bees and wasps between heterogeneous small-scale farming areas and protected forest in northern coastal Belize, Central America. Malaise traps operated for three months during the transition from wet to dry season. Farming areas consisted of a mosaic of mixed crop types, open habitat, secondary forest, and agroforestry. Mean species richness per site (alpha diversity), as well as spatial and temporal community variation (beta diversity) of bees and wasps were equal or higher in farming areas compared to protected forest. The higher species richness and community variation in farmland was due to additional species that did not occur in the forest, whereas most species trapped in forest were also found in farming areas. The overall regional species richness (gamma diversity) increased by 70% with the inclusion of farming areas. Our results suggest that small-scale farming systems adjacent to protected forest may not only conserve, but even favour, biodiversity of some taxonomic groups. We can, however, not exclude possible declines of bee and wasp diversity in more intensified farmland or in landscapes completely covered by heterogeneous farming systems.

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Rural livelihoods in developing countries can be enhanced by improving access to natural resources, services, and markets. In remote rural areas of the humid or semihumid tropics, forests represent an important resource for livelihoods. In countries like Laos, where most primary forest has been converted to secondary forest, and where an intricate and interlinked mosaic of forest and farmland prevails, people depend on secondary forests as a prime source of goods and services. The linkages between local livelihoods and secondary forest resources are subject to changes caused by improving accessibility. This article studies how accessibility affects the condition of forests and local livelihoods by comparing three villages along a gradient of accessibility in Phonxay district, Luang Prabang province, northern Laos. The results of this research show that accessibility strengthens the influence of the government and of markets, and that local livelihoods improve with increasing accessibility, while forest condition deteriorates.

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There is a lively debate on whether biodiversity conservation and agricultural production could be better reconciled by land sparing (strictly separating production fields and conservation areas) or by land sharing (combining both, agricultural production and biodiversity conservation on the same land). The debate originates from tropical countries, where agricultural land use continues to increase at the expense of natural ecosystems. But is it also relevant for Europe, where agriculture is withdrawing from marginal regions whilst farming of fertile lands continues to be intensified? Based on recent research on farmland biodiversity we conclude that the land sharing – land sparing dichotomy is too simplistic for Europe. Instead we differentiate between productive and marginal farmland. On productive farmland, semi-natural habitats are required to yield ecosystem services relevant for agriculture, to promote endangered farmland species which society wants to conserve even in intensively farmed regions, and to allow migration of non-farmland species through the agricultural matrix. On marginal farmland, high-nature value farming is a traditional way of land sharing, yielding high quality agricultural products and conserving specialized species. To conserve highly disturbance-sensitive species, there is a need for nature reserves. In conclusion, land sparing is not a viable olution for Europe in both productive and marginal farmland but because of different reasons in each type of farmland.

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South African land restitution, by way of which the post-apartheid state compensates victims of racial land dispossession, has been intimately linked to former homelands: prototypical rural claims are those of communities that lost their rights in land when being forcibly relocated to reserves and they now aspire to return to their former lands and homes from their despised ‘homelands’. However, white farmers, who were also dispossessed (although usually compensated) by the apartheid state in the latter’s endeavour to consolidate existing homelands, have lodged restitution claims as well. While the Land Claims Court has principally admitted such restitution claims and ruled upon the merits of individual cases, state bureaucrats, legal activists, as well as other members of the public have categorically questioned and challenged such claims to land rights by whites. Focussing on white land claimaints effected by the establishment of former KwaNdebele, this paper investigates the contested field of moral entitlements emerging from divergent discourses about the true victims and beneficiaries of apartheid. It pays particular attention to land claims pertaining to the western frontier of KwaNdebele – the wider Rust de Winter area, which used to be white farmland expropriated in the mid-1980s for consolidation (that never occurred) and currently vegetates as largely neglected no-man’s-(state-)land under multiple land claims. Being the point of reference for state officials, former white farmers, Ndebele traditionalists, local residents, and other citizens, this homeland frontier is hence analysed as a fateful zone of contestation, in which the terms of a new South African moral community are negotiated.

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Porcine reproductive and respiratory syndrome virus (PRRSV) is wide-spread in pig populations globally. In many regions of Europe with intensive pig production and high herd densities, the virus is endemic and can cause disease and production losses. This fuels discussion about the feasibility and sustainability of virus elimination from larger geographic regions. The implementation of a program aiming at virus elimination for areas with high pig density is unprecedented and its potential success is unknown. The objective of this work was to approach pig population data with a simple method that could support assessing the feasibility of a sustainable regional PRRSV elimination. Based on known risk factors such as pig herd structure and neighborhood conditions, an index characterizing individual herds' potential for endemic virus circulation and reinfection was designed. This index was subsequently used to compare data of all pig herds in two regions with different pig- and herd-densities in Lower Saxony (North-West Germany) where PRRSV is endemic. Distribution of the indexed herds was displayed using GIS. Clusters of high herd index densities forming potential risk hot spots were identified which could represent key target areas for surveillance and biosecurity measures under a control program aimed at virus elimination. In an additional step, for the study region with the higher pig density (2463 pigs/km(2) farmland), the potential distribution of PRRSV-free and non-free herds during the implementation of a national control program aiming at national virus elimination was modeled. Complex herd and trade network structures suggest that PRRSV elimination in regions with intensive pig farming like that of middle Europe would have to involve legal regulation and be accompanied by important trade and animal movement restrictions. The proposed methodology of risk index mapping could be adapted to areas varying in size, herd structure and density. Interpreted in the regional context, this could help to classify the density of risk and to accordingly target resources and measures for elimination.