984 resultados para landscape change


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Around the world coastal areas are witnessing dramatic changes due to the consequences of the growth of human settlements. Rapid urban expansion in coastal settlements due to ‘life style migration’ impacts negatively on environmental coastal amenities that are the driving factor behind the attraction of these areas. The Victorian Coast in Australia is under stress, with the growth pattern of coastal settlements in a sprawling linear fashion resulting in devastating effects on the natural coastal environment, biodiversity and the loss of cultural heritage. The Victorian coast is rich in history, and the coastal towns are often described in literature as places with ‘sense of place’, or referred to as place character. This place character has been formed over many years with the interaction between social histories and natural environments woven together across time. This paper reviews the transition of the landscapes along the Great Ocean Road coastal region, and ask the question how can a potential Generative Plan be developed to establish a process to keep the place character of coastal towns. The proposed plan considers the interrelationships of nature and people as fundamental to forming place character, from the time of Indigenous habitation before European settlement, to the current day of rapid increased developments scattered along this coast.

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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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Aerial imagery collected before and after major storm events is ideal for the assessment of coastal landscape change driven by individual high-magnitude events. Using traditional satellite sensors and manned aerial systems can be challenging due to issues related to cloud cover, mobilization expenses and resolution. Rapid advances in unmanned aerial vehicle (UAV) technology allow for the cost-effective collection of aerial imagery and topography at centimetre resolution suitable for assessing change in coastal ecosystems. In this study we demonstrate the utility of UAV-based photogrammetry to quantify storm-driven sediment dynamics on a sandy beach on the open-coast shoreline of Victoria, Australia. UAV-based aerial photography was collected before and after a major storm event. High-resolution (< 5 cm) aerial imagery and digital surface models were acquired and change-detection techniques were applied to quantify changes in the beachface. An average beach erosion of 12.24 m3/m with a maximum of 28.05 m3/m was observed, and the volume of sand cut from the beachface and retreat of the foredune are clearly illustrated. Following the storm event, erosion was estimated at 7259.94 ± 503.69 m3 along 550 m of beach. By combining the aerial imagery and derived topographic datasets we demonstrate the advantage of UAV-based photogrammetry techniques for rapid high-resolution data collection in semi-remote locations. Its utility in setting unlimited virtual vantage points is also illustrated and the valuable perspective it provides for tracking landscape change discussed.

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Pós-graduação em Geografia - IGCE

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ABSTRACT: Kaempfer's Woodpecker (Celeus obrieni) is the only species of the genus Celeus endemic to Brazil. The description of this taxon as a subspecies of the Rufous-headed Woodpecker (Celeus spectabilis) was based on a single specimen. While C. obrieni and C. spectabilis are now considered separate species based on morphological and limited molecular evidence, no study has critically tested the reciprocal monophyly and degree of evolutionary independence between these taxa with several specimens. Herein, fragments of the mitochondrial and nuclear DNA of three recently-collected specimens of C. obrieni were analyzed to evaluate the degree of evolutionary differentiation of this taxon with respect to C. spectabilis. The results confirm the reciprocal monophyly between the specimens of C. obrieni and C. spectabilis. The genetic divergence values for the two taxa also support their classification as independent species, given that they are greater than the values recorded among other closely-related but separate species of the same genus. Estimates of the divergence time between C. obrieni and C. spectabilis indicate that cladogenesis occurred in the mid-Pleistocene, during a period of major climatic fluctuations and landscape change, consistent with the hypothesis of a corridor of open bamboo dominated forests and woodland stretching.

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Far from the continental margin, drainage basins in Central Amazonia should be in topographic steady state; but they are not. Abandoned remnant fluvial valleys up to hundreds of square kilometers in size are observed throughout Amazonia, and are evidence of significant landscape reorganization. While major Late Miocene drainage shifts occurred due to initiation of the transcontinental Amazon River, local landscape change has remained active until today. Driven either by dynamic topography, tectonism, and/or climatic fluctuations, drainage captures in Amazonia provide a natural experiment for assessing the geomorphic response of low-slope basins to sudden, capture related base-level falls. This paper evaluates the timing of geomorphic change by examining a drainage capture event across the Baependi fault scarp involving the Cuieiras and TarumA-Mirim River basins northwest of the city of Manaus in Brazil. A system of capture-related knickpoints was generated by base-level fall following drainage capture; through numerical modeling of their initiation and propagation, the capture event is inferred to have occurred between the middle and late Pleistocene, consistent with other studies of landscape change in surrounding areas. In low-slope settings like the Amazon River basin, base-level fall can increase erosion rates by more than an order of magnitude, and moderate to large river basins can respond to episodes of base-level fall over timescales of tens to hundreds of thousands of years. Copyright (c) 2013 John Wiley & Sons, Ltd.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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This study was conducted to verify water quality and environmental impacts related to the occupation of the watershed of the Bandeirantes stream, located in Rio Claro, SP. The intention is to propose measures to enable the mitigation of negative impacts, and boosting the recovery and maintenance of the quality of water resources, preventing its complete degradation. Water analysis were performed at three different points, east, crossing the Ring Road (dirt road) and near the confluence with the Ribeirão Claro. The results indicated significant degradation of water, especially after the crossing, where it witnessed the accumulation of solid waste and easy access to the stream, both for animals as for people, due to limited riparian it. Another impact was observed the current construction of the Forum of Rio Claro in the right side of the stream studied, causing change in the landscape, change the flow properties and removal of existing vegetation at the site of work, defined as an environmentally protected area, as determined by existing law. Measures such as: restoration of riparian zones, effluent treatment, planned urban growth and environmental education of the population, would be essential to mitigate the environmental impacts of watershed Bandeirantes stream

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Protocols for rapid habitat evaluation and the biotic indices used in biomonitoring of streams in Brazil provide useful information about water quality and modifications in the ecosystem. However, the interpretation of their results is limited. Previous studies pointed out the low sensitivity of those indices to measure the quality of low-order streams, since they only measure organic impacts. Environmental degradation of these streams is mainly related to impacts caused by landscape change, such as erosion, siltation, channel change, loss of riparian vegetation, and reduction in water flow. The streams of the Serra do Japi are under some of these impacts, caused by agricultural activities. In this study, we evaluated whether the reduction of natural characteristics in these environments would decrease water quality. The Protocol of Habitat Diversity was affected by the impacts of agricultural activities. However, the other three biotic indices: Biological Monitoring Working Party Score System, Average Score Per Taxon, and Index of Benthic Community were not as sensitive to those impacts, since they all indicated a high water quality. An adaptation of the attributes and the scoring system is suggested for defining better policies for the conservation of this area.

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The north-eastern escarpment of Madagascar has been labelled a global biodiversity hotspot due to its extremely high rates of endemic species which are heavily threatened by accelerated deforestation rates and landscape change. The traditional practice of shifting cultivation or "tavy" used by the majority of land users in this area to produce subsistence rice is commonly blamed for these threats. A wide range of stakeholders ranging from conservation to development agencies, and from the private to the public sector has therefore been involved in trying to find solutions to protect the remaining forest fragments and to increase agricultural production. Consequently, provisioning, regulating and socio-cultural services of this forest-mosaic landscape are fundamentally altered leading to trade-offs between them and consequently new winners and losers amongst the stakeholders at different scales. However, despite a growing amount of evidence from case studies analysing local changes, the regional dynamics of the landscape and their contribution to such trade-offs remain poorely understood. This study therefore aims at using generalised landscape units as a base for the assessment of multi-level stakeholder claims on ecosystem services to inform negotiation, planning and decision making at a meso-scale. The presented study applies a mixed-method approach combining remote sensing, GIS and socio-economic methods to reveal current landscape dynamics, their change over time and the corresponding ecosystem service trade-offs induced by diverse stakeholder claims on the regional level. In a first step a new regional land cover classification for three points in time (1995, 2005 and 2011) was conducted including agricultural classes characteristic for shifting cultivation systems. Secondly, a novel GIS approach, termed “landscape mosaics approach” originally developed to assess dynamics of shifting cultivation landscapes in Laos was applied. Through this approach generalised landscape mosaics were generated allowing for a better understanding of changes in land use intensities instead of land cover. As a next step we will try to use these landscape units as proxies to map provisioning and regulating ecosystem services throughout the region. Through the overlay with other regional background data such as accessibility and population density and information from a region-wide stakeholder analysis, multiscale trade-offs between different services will be highlighted. The trade-offs observed on the regional scale will then be validated through a socio-economic ground-truthing within selected sites at the local scale. We propose that such meso-scale knowledge is required by all stakeholders involved in decision making towards sustainable development of north-eastern Madagascar.

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Thermal permafrost degradation and coastal erosion in the Arctic remobilize substantial amounts of organic carbon (OC) and nutrients which have accumulated in late Pleistocene and Holocene unconsolidated deposits. Permafrost vulnerability to thaw subsidence, collapsing coastlines and irreversible landscape change are largely due to the presence of large amounts of massive ground ice such as ice wedges. However, ground ice has not, until now, been considered to be a source of dissolved organic carbon (DOC), dissolved inorganic carbon (DIC) and other elements which are important for ecosystems and carbon cycling. Here we show, using biogeochemical data from a large number of different ice bodies throughout the Arctic, that ice wedges have the greatest potential for DOC storage, with a maximum of 28.6 mg/L (mean: 9.6 mg/L). Variation in DOC concentration is positively correlated with and explained by the concentrations and relative amounts of typically terrestrial cations such as Mg2+ and K+. DOC sequestration into ground ice was more effective during the late Pleistocene than during the Holocene, which can be explained by rapid sediment and OC accumulation, the prevalence of more easily degradable vegetation and immediate incorporation into permafrost. We assume that pristine snowmelt is able to leach considerable amounts of well-preserved and highly bioavailable DOC as well as other elements from surface sediments, which are rapidly frozen and stored in ground ice, especially in ice wedges, even before further degradation. We found that ice wedges in the Yedoma region represent a significant DOC (45.2 Tg) and DIC (33.6 Tg) pool in permafrost areas and a freshwater reservoir of 4200 km**3. This study underlines the need to discriminate between particulate OC and DOC to assess the availability and vulnerability of the permafrost carbon pool for ecosystems and climate feedback upon mobilization.

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Este estudio de caso de un paisaje agrícola en un sistema de huerta tradicional de la provincia de Alicante fue llevado a cabo para desarrollar técnicas adecuadas de cuantificación y análisis del paisaje en el período 1883-2007. Los métodos utilizados se derivan del análisis de cambio en la estructura del paisaje, basado en antiguos mapas y fotografías aéreas, siendo adaptados a una escala detallada por medio de herramientas SIG. La base de datos creada para este análisis diacrónico es una pieza fundamental para obtener una clara visión de la evolución de los usos del suelo en el área de estudio. El principal objetivo de este estudio es poner de manifiesto que una aproximación a nivel de parcela, utilizando tecnologías SIG, proporciona valiosos resultados para planificar programas de conservación en paisajes agrícolas a escala local.

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Remotely sensed data have been used extensively for environmental monitoring and modeling at a number of spatial scales; however, a limited range of satellite imaging systems often. constrained the scales of these analyses. A wider variety of data sets is now available, allowing image data to be selected to match the scale of environmental structure(s) or process(es) being examined. A framework is presented for use by environmental scientists and managers, enabling their spatial data collection needs to be linked to a suitable form of remotely sensed data. A six-step approach is used, combining image spatial analysis and scaling tools, within the context of hierarchy theory. The main steps involved are: (1) identification of information requirements for the monitoring or management problem; (2) development of ideal image dimensions (scene model), (3) exploratory analysis of existing remotely sensed data using scaling techniques, (4) selection and evaluation of suitable remotely sensed data based on the scene model, (5) selection of suitable spatial analytic techniques to meet information requirements, and (6) cost-benefit analysis. Results from a case study show that the framework provided an objective mechanism to identify relevant aspects of the monitoring problem and environmental characteristics for selecting remotely sensed data and analysis techniques.

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Beginning in the era of the Spanish conquest and taking the reader right up to the present day, this book focuses on how the landscape of Cuba has changed and evolved into the environment we see today. It illustrates the range of factors – economic, political and cultural – that have determined Cuba’s physical geography, and explores the shifting conservation measures which have been instituted in response to new methods in agriculture and land management. The text uses historical documents, fieldwork, Geographic Information System (GIS) data and remotely-sensed satellite imagery to detail Cuba’s extensive land-use history as well as its potential future. The author goes further to analyze the manner, speed and methods of landscape change, and examines the historical context and governing agendas that have had an impact on the relationship between Cuba’s inhabitants and their island. Gebelein also assesses the key role played by agricultural production in the framework of international trade required to sustain Cuba’s people and its economy. The book concludes with a review of current efforts by Cuban and other research scientists, as well as private investors, conservation managers and university professors who are involved in shaping Cuba’s evolving landscape and managing it during the country’s possible transition to a more politically diverse, enfranchised and open polity.