996 resultados para Agricultural landscapes


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Weather conditions in critical periods of the vegetative crop development influence crop productivity, thus being a basic parameter for crop forecast. Reliable extended period weather forecasts may contribute to improve the estimation of agricultural productivity. The production of soybean plays an important role in the Brazilian economy, because this country is ranked among the largest producers of soybeans in the world. This culture can be significantly affected by water conditions, depending on the intensity of water deficit. This work explores the role of extended period weather forecasts for estimating soybean productivity in the southern part of Brazil, Passo Fundo, and Londrina (State of Rio Grande do Sul and Parana, respectively) in the 2005/2006 harvest. The goal was to investigate the possible contribution of precipitation forecasts as a substitute for the use of climatological data on crop forecasts. The results suggest that the use of meteorological forecasts generate more reliable productivity estimates during the growth period than those generated only through climatological information.

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In order to facilitate the better management of river basin resources, the Glenelg-Hopkins region in south-east Australia required an accurate and up to date land use map. Land use has a major impact on Australia's natural resources including its soil, water, flora and fauna and plays a major role in determining basin health. Inappropriate land use and practices have contributed to extensive dryland salinity and water quality problems. Land use data is often required for environmental models and in most cases the reliability of model outputs is dependent on the spatial detail and accuracy of the land use mapping. This paper examines methods to obtain an up to date land use map and a detailed accuracy assessment using Landsat ETM+ data for a regional basin. A multi-source based approach allowed the collection of 4817 ground truth data points from the field investigation. This enabled researchers to (i) incorporate a full range of information into digital image analysis with significant improvements in accuracy and (ii) hold sufficient independent references for an accurate error assessment. Classification accuracy was significantly improved using a stratification design, in which the region is sub-divided into smaller homogenous areas as opposed to a full scene classification technique. The overall classification accuracy was 84% (KHAT= 0.833) for the stratified approach compared to 76% (KHAT= 0.743) for the full scene classification. Effective assessment, planning and management of basins are dependent on a sound knowledge of the distribution and variability of land use.

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Habitat loss and fragmentation on the Mornington Peninsula, Victoria, Australia, has resulted in a mosaic of forest patches, forest edges abutted by agricultural land and linear habitat strips amidst a human-modified land matrix. To examine the use of forest elements by the avifauna in this landscape, bird populations were sampled along fixed transects established within forest interiors, on forest edges and along forested roadsides. A total of 60 species was recorded during this study, five of which were introduced. Species richness and diversity did not differ significantly between the three habitat elements, but avifaunal composition varied considerably. The species assemblages of all habitat elements differed significantly, with forest interiors and roadsides showing the greatest difference and forest interiors and forest edges showing the least degree of difference. Forest-dependent bird species used both interiors and edges. Interiors differed from edges and roadsides in having lower abundances of open country species, predatory species and introduced species. A clear gradient of change in bird communities from forest interiors to roadside vegetation was observed. This study suggests that the interiors of medium-sized (<1 000 ha) patches may play an important role in conserving bird biodiversity on a local level as they provide refuge for forest-dependent native species in extensively cleared landscapes.

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The conservation of roosting and nesting resources is of critical concern for many hollow-dependent species around the world. We investigated the nest-tree requirements of the threatened brush-tailed phascogale (Phascogale tapoatafa) in a highly cleared agricultural landscape in south-eastern Australia. We documented the physical characteristics of selected nest trees and describe the spatial and temporal patterns of nest-tree use as revealed by radio-tracking. Nine phascogales (seven females, two males) were radio-tracked between March and July 1999 in an area where most woodland habitat is confined to linear strips along roads and streams or small patches and scattered trees in cleared farmland. Female phascogales were monitored for 13–35 days over periods of 5–15 weeks and two males were monitored for 2 and 9 days respectively. A total of 185 nest-tree fixes was collected and all nests occupied by phascogales were in standing trees. Eighty-three nest trees were identified, ranging in diameter at breast height (dbh) from 25 to 171 cm, with a mean dbh for the trees used by each individual phascogale of >80 cm. Phascogales did not discriminate between canopy tree species in selecting nest trees, but showed highly significant selection for trees in the largest size class. All individuals used multiple nest trees, with the seven females occupying an average of 11.4 nest trees from a mean of 25 diurnal locations. The number of nest trees continued to increase throughout the study, suggesting that more would be identified during a longer or more intensive study. Occupied nest trees were located throughout each individual’s home range, highlighting the importance of a continuous spatial distribution of suitable nest trees across the landscape. Nest trees were also located in adjacent farmland up to 225 m from roadside vegetation, demonstrating the value that scattered clumps and even single trees in farmland can have for wildlife conservation.

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Although e-government offers unique opportunities for streamlining good governance, there remains considerable skepticism about its applicability in developing countries due to their lack of required level of infrastructural, technological, legal and human development. This paper argues that developing countries can introduce e-government practices by re-engineering their existing infrastructure rather than waiting for massive investments and perfect technological advancements. Using Bangladesh- a developing country- as an exemplar, this paper assesses the applicability and prospects of e-government practices in dealing with the problems in the agricultural input sector which is predominantly associated with poor, marginalised and semi-illiterate farmers. The utilization of the Bangladesh case study has important implications for examining and highlighting the probable introduction of e-government practices in developing countries.

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In this paper, we analyse the case for agricultural land retirement in Australia. For the case study considered, using defined criteria, we demonstrate that land retirement is an effective policy option. This finding depends crucially on the magnitude and sign of the price effect resulting from a fall in wool production because of agricultural land retirement. Uniquely in the literature, we argue that the price effect will positively contribute to a benefit–cost analysis of agricultural land retirement. We detail the necessary conditions that need to prevail for this to occur. We also explain why the expected benefits of land-use change are fewer than might be expected in the case study.

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IP a The paper examines the application of the Resource-Based View of strategy (RBV) to the Australian floral industry. Despite the RBV's successful application to research in a number of discipline areas and the formalisation of its relationship with Competitive Advantage (CA) 15 years ago, the empirical support for the benefit of the RBV and development of research constructs has been inadequate. This has been partly due to the difficulty of identifying and separating the contribution of resources. The RBV literature is now consistent in the criteria required of a resource for CA and identifies a range of empirical research objectives (e.g. the need for contextual constructs), data evaluation focuses (e.g. measuring the impact of management, process, regional and scale affects) and results objectives (such as identifying the causal structure of resources). Research was conducted in the Australian floral industry to produce supporting generalisable data and constructs for the RBV. This industry is well bounded with several strongly differentiating resources and operates in a global market environment, which is necessary for these research objectives. Six hypotheses were examined; (1) the use of resources as the input of the CA, (2) the impact of the development process on resources, (3) the impact of management control on the development of resources (4) the impact on capability of management, process, region and scale, (5) the impact of resource development maturity on the approach to resource development and (6) the possibility of evaluating individual resources according to various criteria. The data was collected using selected participant interviews, with validation of conclusions by industry experts. It was analysed using content analysis, comparative analysis and cognitive mapping. The research determined that organisations in the Australian floral industry possessed important resources including geography, skills, technology, R&D, supply chains and production costs. These contributed to four CA creating production outputs; quality, capacity, reliability and customer convenience. The research findings supported hypotheses 1, 3, 4, 5 and 6. The lack of support for the two remaining hypotheses, relating to the process of resource development, may be explained by the low resource development maturity of the industry which masks the impact of the resource development process. The results also determined that one resource could contribute to a number of CAs and that resources not meeting all of the normal RBV CA criteria could still provide a CA in an industry where few resources met all criteria. It was postulated that these resources’ contribution to competitive was not durable.

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Nestedness in biota as a function of species richness – biota of depauperate assemblages being non-random subsets of richer biotas – has been widely documented in recent years (see Wright et al. 1998, Oecologia 113: 1–20). Ordering sites by richness maximizes nestedness indices; however, ordering by other criteria such as area or isolation may be more ecologically interpretable. We surveyed birds in true fragments (35 in all), and in "reference areas" in large extant forest blocks (30 locations), of the same range of areas (10, 20, 40, 80 ha). The avifauna was divided into "bush birds"– species dependent on forest and woodland, and "open country" species. We looked at nestedness in four data sets: "bush birds" in fragments and reference areas, and "all birds" in fragments and in reference areas. All data sets were significantly nested. Ordering by area in all cases was not significantly less nested than ordering by richness. Ordering by area in fragments was significantly greater than in reference areas, but the differences in standardized nestedness indices were small (<15%). We identified those birds that had distributions among fragments that conformed strongly with area, those that were more randomly distributed and some species that were more likely to occupy the smallest fragments. Among the latter was a hyperaggressive, invasive, colonial native species (noisy miner Manorina melanocephala). A suite of small, insectivorous birds were more likely to strongly conform with expected distributions in relation to area, which was consistent with observations of their vulnerability to the effects of the noisy miner in smaller fragments.

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