868 resultados para agricultural landscapes
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Detailed data on land use and land cover constitute important information for Earth system models, environmental monitoring and ecosystem services research. Global land cover products are evolving rapidly; however, there is still a lack of information particularly for heterogeneous agricultural landscapes. We censused land use and land cover field by field in the agricultural mosaic catchment Haean in South Korea. We recorded the land cover types with additional information on agricultural practice. In this paper we introduce the data, their collection and the post-processing protocol. Furthermore, because it is important to quantitatively evaluate available land use and land cover products, we compared our data with the MODIS Land Cover Type product (MCD12Q1). During the studied period, a large portion of dry fields was converted to perennial crops. Compared to our data, the forested area was underrepresented and the agricultural area overrepresented in MCD12Q1. In addition, linear landscape elements such as waterbodies were missing in the MODIS product due to its coarse spatial resolution. The data presented here can be useful for earth science and ecosystem services research.
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As paisagens rurais portuguesas construídas e mantidas ao longo dos tempos por sistemas agrícolas tradicionais, estão hoje ameaçadas por motivos tão diversos como o envelhecimento da população, o abandono rural, a intensificação, a homogeneização dos sistemas de produção e a perda de competitividade. Mas apesar destes problemas, estas paisagens agrícolas, suportam ainda várias funções não produtivas, nomeadamente, constituem, um importante suporte de biodiversidade, pelo que a sua manutenção é importante para a conservação destes habitats e espécies. Eventualmente novas formas de gestão destas paisagens devem ser criadas, nomeadamente com base na combinação de várias funções numa perspectiva de multifuncionalidade, através de uma adaptação e integração de políticas públicas. Estando actualmente em discussão o novo programa de Desenvolvimento Rural e a definição das futuras Medidas Agro-Ambientais, e a gestão e o financiamento da Rede Natura 2000, estamos portanto num momento crítico para decisões futuras, que terão forçosamente que interligar, a agricultura, o ambiente e desenvolvimento das zonas rurais portuguesas. Com o intuito de melhor compreender estas problemáticas, em particular, as transformações em curso na paisagem rural, o papel das Medidas Agro-Ambientais e apresentar possíveis soluções, foi efectuado este estudo de caso no concelho de Marvão, concelho típico das áreas marginais agrícolas do interior sul de Portugal. ABSTRACT; The Portuguese rural landscapes built up and kept throughout the times by traditional agricultural systems, are today threatened by so diverse reasons as the ageing of the population, the agricultural abandonment, the intensification, the homogenization of the production systems and the loss of competitiveness. But despite these problems. These agricultural landscapes still support a multitude of non-commodity functions, and particularly they still constitute an important support of biodiversity and thus their maintenance is important for the conservation of these habitats and species. Probably new management forms must be created based on the combination of various functions and the adaptation and integration of public policies. Being currently in discussion the new program of Rural Development and the definition of the future Agri-Environmental Measures, and the management and the financing of the Natura 2000 Network, we are therefore at a critical moment for future decisions that will forcibly have to establish connections, between the agriculture, the environment and the development of the portuguese agricultural areas. With the intention of better understanding these problems and questions, , the transformations taking place in Portuguese peripheric rural areas, and in particular role of the Agri-Environmental Measures, and also for presenting possible solutions, a case study was analyzed in municipality of Marvão, characteristic of the agricultural marginal areas of the interior Southern Portugal.
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Failure to detect a species at sites where it is present (i.e. imperfect detection) is known to occur frequently, but this is often disregarded in monitoring programs and metapopulation studies. Here we modelled for the first time the probability of patch occupancy by a threatened small mammal, the southern water vole (Arvicola sapidus, while accounting for the probability of detection given occupancy. Based on replicated presence sign surveys conducted in autumn (November–December 2013) and winter (February–March 2014) in a farmland landscape, we used occupancy detection modelling to test the effects of vegetation, sampling effort, observer experience, and rainfall on detection probability. We then assessed whether occupancy was related to patch size, isolation, vegetation, or presence of water, after correcting for imperfect detection. The mean detection probabilities of water vole signs in autumn (0.71) and winter (0.81) indicated that false absences may be generated in about 20–30% of occupied patches surveyed by a single observer on a single occasion. There was no statistical support for the effects of covariates on detectability. After controlling for imperfect detection, the mean probabilities of occupancy in autumn (0.31) and winter (0.29) were positively related to patch size and presence of water, and negatively so, albeit weakly, to patch isolation. Overall, our study underlined the importance of accounting for imperfect detection in sign surveys of small mammals such as water voles, pointing out the need to use occupancy detection modelling together with replicate surveys for accurately estimating occupancy and the factors affecting it.
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Parthenium is a weed of global significance affecting many countries in Asia, Africa, and the Pacific Islands. Parthenium causes severe human and animal health problems, agricultural losses as well as serious environmental problems. Management options for parthenium include chemical, physical, legislative, fire, mycoherbicides, agronomic practices, competitive displacement and classical biological control. The ability of parthenium to grow in a wide range of habitats, its persistent seed bank, and its allelopathic potential make its management difficult. No single management option would be adequate to manage parthenium across all habitats, and there is a need to integrate various management options (e.g. grazing management, competitive displacement, cultural practices) with classical biological control as a core management option.
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In the Mackay Whitsunday region, the dominant grazing based operations are small intensive systems that heavily utilise soil, nutrient and chemical management practices. To improve water quality entering the Great Barrier Reef, graziers are being encouraged to adopt improved management practices. However, while there is good understanding of the management changes required to reach improved practice classification levels, there is poor understanding of the likely economic implications for a grazier seeking to move from a lower level classification to the higher level classifications. This paper provides analysis of the costs and benefits associated with adoption of intensive grazing best management practices to determine the effect on the profitability and economic sustainability of grazing enterprises, and the economic viability of capital investment to achieve best management. The results indicate that financial incentives are likely to be required to encourage smaller graziers to invest in changing their management practices, while larger graziers may only require incentives to balance the risk involved with the transition to better management practices.
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Intensified agricultural practises introduced after the Second World War are identified as a major cause of global biodiversity declines. In several European countries agri-environment support schemes have been introduced to counteract the ongoing biodiversity declines. Farmers participating in agri-environment schemes are financially compensated for decreasing the intensity of farming practises leading to smaller yields and lower income. The Finnish agri-environment support scheme is composed of a set of measures, such as widened field margins along main ditches (obligatory measure), management of features increasing landscape diversity, management of semi-natural grasslands, and organic farming (special agreement measures). The magnitude of the benefits for biodiversity depends on landscape context and the properties of individual schemes. In this thesis I studied whether one agri-environment scheme, organic farming, is beneficial for species diversity and abundance of diurnal lepidopterans, bumblebees, carabid beetles and arable weeds. I found that organic farming did not enhance species richness of selected insect taxa, although bumblebee species richness tended to be higher in organic farms. Abundance of lepidopterans and bumblebees was not enhanced by organic farming, but carabid beetle abundance was higher in mixed farms with both cereal crop production and animal husbandry. Both species richness and abundance of arable weeds were higher in organic farms. My second objective was to study how landscape structure shapes farmland butterfly communities. I found that the percentage of habitat specialists and species with poor dispersal abilities in butterfly assemblages decreased with increasing arable field cover, leading to a dramatic decrease in butterfly beta diversity. In field boundaries local species richness of butterflies was linearly related to landscape species richness in geographic regions with high arable field cover, indicating that butterfly species richness in field boundaries is more limited by landscape factors than local habitat factors. In study landscapes containing semi-natural grasslands the relationship decelerated at high landscape species richness, suggesting that local species richness of butterflies in field boundaries is limited by habitat factors (demanding habitat specialists that occurred in semi-natural grasslands were absent in field margins). My results suggest that management options in field margins will affect mainly generalists, and species with good dispersal abilities, in landscapes with high arable field cover. Habitat specialists and species with poor dispersal abilities may benefit of management options if these are applied in the vicinity of source populations.
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Wildlife conservation in human-dominated landscapes requires that we understand how animals, when making habitat-use decisions, obtain diverse and dynamically occurring resources while avoiding risks, induced by both natural predators and anthropogenic threats. Little is known about the underlying processes that enable wild animals to persist in densely populated human-dominated landscapes, particularly in developing countries. In a complex, semi-arid, fragmented, human-dominated agricultural landscape, we analyzed the habitat-use of blackbuck, a large herbivore endemic to the Indian sub-continent. We hypothesized that blackbuck would show flexible habitat-use behaviour and be risk averse when resource quality in the landscape is high, and less sensitive to risk otherwise. Overall, blackbuck appeared to be strongly influenced by human activity and they offset risks by using small protected patches (similar to 3 km(2)) when they could afford to do so. Blackbuck habitat use varied dynamically corresponding with seasonally-changing levels of resources and risks, with protected habitats registering maximum use. The findings show that human activities can strongly influence and perhaps limit ungulate habitat-use and behaviour, but spatial heterogeneity in risk, particularly the presence of refuges, can allow ungulates to persist in landscapes with high human and livestock densities.
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Traditional agricultural systems are threatened world-wide mainly due to the introduction of modern agricultural techniques and the emigration of farm labourers from remote rural villages. The objective of the programme 'Globally Important Agricultural Heritage Systems' (GIAHS), initiated by the Food and Agriculture Organization (FAO) of the United Nations in 2002, is dynamic conservation of traditional agricultural systems. This article addresses the definition and content of agricultural heritage systems and discusses conservation options in the light of developing rural tourism. An explorative survey was conducted in Longxian village, situated in Zhejiang Province, southern China, focusing on the tourism potential of a typical Rice-Fish Agricultural System. The identification of heritage resources is a first step in the process of transforming an agricultural landscape into a cultural tourism landscape. However, the future of these landscapes is in the hands of a range of stakeholders and depends on their capacity to manage, in a sustainable way, tourism development strategies alongside conservation policies.
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The present study examines those features which promote bat feeding in agricultural riparian areas and the riparian habitat associations of individual species. Activity of Nathusius' pipistrelle (Pipistrellus nathusii), common pipistrelle (Pipistrellus pipistrellus), soprano pipistrelle (Pipistrellus pygmaeus), Leisler's bat (Nyctalus leisleri), and Myotis species (Myotis sp.) were recorded, and their habitat associations both "between" and "within" riparian areas were analyzed. General feeding activity was associated with reduced agricultural intensity, riparian hedgerow provision, and habitat diversity. Significant habitat associations for P. pipistrellus were observed only within riparian areas. Myotis species and P. pygmaeus were significantly related to indices of landscape structure and riparian hedgerow across spatial scales. Myotis species were also related to lower levels of riffle flow at both scales of analysis. The importance of these variables changed significantly, however, between analysis scales. The multi-scale investigation of species-habitat associations demonstrated the necessity to consider habitat and landscape characteristics across spatial scales to derive appropriate conservation plans.
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Agricultural intensification can affect biodiversity and related ecosystem services such as biological control, but large-scale experimental evidence is missing. We examined aphid pest populations in cereal fields under experimentally reduced densities of (1) ground-dwelling predators (-G), (2) vegetation-dwelling predators and parasitoids (-V), (3) a combination of (1) and (2) (-G-V),compared with open-fields (control), in contrasting landscapes with low vs. high levels of agricultural intensification (AI), and in five European regions. Aphid populations were 28%, 97%, and 199% higher in -G, -V, and -G -V treatments, respectively, compared to the open fields, indicating synergistic effects of both natural-enemy groups. Enhanced parasitoid : host and predator : prey ratios were related to reduced aphid population density and population growth. The relative importance of parasitoids and vegetation-dwelling predators greatly differed among European regions, and agricultural intensification affected biological control and aphid density only in some regions. This shows a changing role of species group identity in diverse enemy communities and a need to consider region-specific landscape management.
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Community structure depends on both deterministic and stochastic processes. However, patterns of community dissimilarity (e.g. difference in species composition) are difficult to interpret in terms of the relative roles of these processes. Local communities can be more dissimilar (divergence) than, less dissimilar (convergence) than, or as dissimilar as a hypothetical control based on either null or neutral models. However, several mechanisms may result in the same pattern, or act concurrently to generate a pattern, and much research has recently been focusing on unravelling these mechanisms and their relative contributions. Using a simulation approach, we addressed the effect of a complex but realistic spatial structure in the distribution of the niche axis and we analysed patterns of species co-occurrence and beta diversity as measured by dissimilarity indices (e.g. Jaccard index) using either expectations under a null model or neutral dynamics (i.e., based on switching off the niche effect). The strength of niche processes, dispersal, and environmental noise strongly interacted so that niche-driven dynamics may result in local communities that either diverge or converge depending on the combination of these factors. Thus, a fundamental result is that, in real systems, interacting processes of community assembly can be disentangled only by measuring traits such as niche breadth and dispersal. The ability to detect the signal of the niche was also dependent on the spatial resolution of the sampling strategy, which must account for the multiple scale spatial patterns in the niche axis. Notably, some of the patterns we observed correspond to patterns of community dissimilarities previously observed in the field and suggest mechanistic explanations for them or the data required to solve them. Our framework offers a synthesis of the patterns of community dissimilarity produced by the interaction of deterministic and stochastic determinants of community assembly in a spatially explicit and complex context.
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Agricultural management of grassland in lowland Britain has changed fundamentally in the last 50 years, resulting in spatial and structural uniformity within the pastoral landscape. The full extent to which these changes may have reduced the suitability of grassland as foraging habitat for birds is unknown. This study investigated the mechanisms by which these changes have impacted on birds and their food supplies. We quantified field use by birds in summer and winter in two grassland areas of lowland England (Devon and Buckinghamshire) over 3 years, relating bird occurrence to the management, sward structure and seed and invertebrate food resources of individual fields. Management intensity was defined in terms of annual nitrogen input. There was no consistent effect of management intensity on total seed head production, although those of grasses generally increased with inputs while forbs were rare throughout. Relationships between management intensity and abundance of soil and epigeal invertebrates were complex. Soil beetle larvae were consistently lower in abundance, and surface-active beetle larvae counts consistently higher, in intensively managed fields. Foliar invertebrates showed more consistent negatively relationships with management intensity. Most bird species occurred at low densities. There were consistent relationships across regions and years between the occurrence of birds and measures of field management. In winter, there was a tendency towards higher occupancy of intensively managed fields by species feeding on soil invertebrates. In summer, there were few such relationships, although many species avoided fields with tall swards. Use of fields by birds was generally not related to measures of seed or invertebrate food abundance. While granivorous species were perhaps too rare to detect a relationship, in insectivores the strong negative relationships (in summer) with sward height suggested that access to food may be the critical factor. While it appears that intensification of grassland management has been deleterious to the summer food resources of insectivorous birds that use insects living within the grass sward, intensification may have been beneficial to several species in winter through the enhancement of soil invertebrates. Synthesis and applications. We suggest that attempts to restore habitat quality for birds in grassland landscapes need to create a range of management intensities and sward structures at the field and farm scales. A greater understanding of methods to enhance prey accessibility, as well as abundance, for insectivorous birds is required.
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Background: Up to 75% of crop species benefit at least to some degree from animal pollination for fruit or seed set and yield. However, basic information on the level of pollinator dependence and pollinator contribution to yield is lacking for many crops. Even less is known about how insect pollination affects crop quality. Given that habitat loss and agricultural intensification are known to decrease pollinator richness and abundance, there is a need to assess the consequences for different components of crop production. Methods: We used pollination exclusion on flowers or inflorescences on a whole plant basis to assess the contribution of insect pollination to crop yield and quality in four flowering crops (spring oilseed rape, field bean, strawberry, and buckwheat) located in four regions of Europe. For each crop, we recorded abundance and species richness of flower visiting insects in ten fields located along a gradient fromsimple to heterogeneous landscapes. Results: Insect pollination enhanced average crop yield between 18 and 71% depending on the crop. Yield quality was also enhanced in most crops. For instance, oilseed rape had higher oil and lower chlorophyll contents when adequately pollinated, the proportion of empty seeds decreased in buckwheat, and strawberries’ commercial grade improved; however, we did not find higher nitrogen content in open pollinated field beans. Complex landscapes had a higher overall species richness of wild pollinators across crops, but visitation rates were only higher in complex landscapes for some crops. On the contrary, the overall yield was consistently enhanced by higher visitation rates, but not by higher pollinator richness. Discussion. For the four crops in this study, there is clear benefit delivered by pollinators on yield quantity and/or quality, but it is not maximized under current agricultural intensification. Honeybees, the most abundant pollinator, might partially compensate the loss of wild pollinators in some areas, but our results suggest the need of landscape-scale actions to enhance wild pollinator populations.
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Increasing population size and demand for food in the developing world is driving the intensification ofagriculture, often threatening the biodiversity within the farmland itself and in the surrounding land-scape. This paper quantifies bird and tree species richness, tree carbon and farmer’s gross income, andinteractions between these four variables, across an agricultural gradient in central Uganda. We showedthat higher cultivation intensities in farmed landscapes resulted in increased income but also a declinein species richness of birds and trees, and reductions in tree carbon storage. These declines were particu-larly marked with a shift from high intensity smallholder mixed cropping to plantation style agriculture.This was especially evident for birds where significant declines only occurred in plantations. Small scalefarming will likely continue to be a key source of cash income for the rural populations, and ensuring‘sustained agricultural growth’ within such systems while minimising negative impacts on biodiversityand other key ecosystem services will be a major future challenge.