799 resultados para temporary landscape


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Thesis (Master's)--University of Washington, 2016-06

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The major objective of this study was to determine the relative importance of landscape factors, local abiotic factors, and biotic interactions in influencing tadpole community structure in temporary wetlands. I also examined the influence of agricultural activities in South-central Florida by comparing tadpole communities in native prairie wetlands (a relatively unmodified habitat) at the Kissimmee Prairie Sanctuary (KPS) to tadpole communities in three agriculturally modified habitats found at MacArthur Agro-Ecology Research Center (MAERC). Environmental characteristics were measured in 24 isolated wetlands, and tadpoles were sampled using throw-traps and dipnets during the 1999 wet season (June–October). Landscape characteristics were expected to predominately influence all aspects of community structure because anurans associated with temporary wetland systems are likely to exist as metapopulations. Both landscape characteristics (wetland proximity to nearest woodland and the amount of woodland surrounding the wetland) and biotic interactions (fish predation) had the largest influence on tadpole community structure. Predatory fish influenced tadpole communities more than expected due to the ubiquity of wetlands, lack of topographic relief, and dispersal abilities of several fish species. Differences in tadpole community structure among habitat types were attributed to differences in woodland attributes and susceptibility to fish colonization. Furthermore, agricultural modification of prairie habitats in South-central Florida may benefit amphibian communities, particularly woodland-dwelling species that are unable to coexist with predatory fish. From a conservation standpoint, temporary wetlands proximal to woodland areas and isolated from permanent water sources appear to be most important to amphibians. In addition, the high tadpole densities attained in these wetlands suggest that these wetlands serve as biological hotspots within the landscape, and their benefits extend into the adjacent terrestrial matrix. Further research efforts are needed to quantify the biological productivity of these systems and determine spatial dynamics of anurans in surrounding terrestrial habitats. ^

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The major objective of this study was to determine the relative importance of landscape factors, local abiotic factors, and biotic interactions in influencing tadpole community structure in temporary wetlands. I also examined the influence of agricultural activities in South-central Florida by comparing tadpole communities in native prairie wetlands (a relatively unmodified habitat) at the Kissimmee Prairie Sanctuary (KPS) to tadpole communities in three agriculturally modified habitats found at MacArthur Agro- Ecology Research Center (MAERC). Environmental characteristics were measured in 24 isolated wetlands, and tadpoles were sampled using throw-traps and dipnets during the 1999 wet season (June - October). Landscape characteristics were expected to predominately influence all aspects of community structure because anurans associated with temporary wetland systems are likely to exist as metapopulations. Both landscape characteristics (wetland proximity to nearest woodland and the amount of woodland surrounding the wetland) and biotic interactions (fish predation) had the largest influence on tadpole community structure. Predatory fish influenced tadpole communities more than expected due to the ubiquity of wetlands, lack of topographic relief, and dispersal abilities of several fish species. Differences in tadpole community structure among habitat types were attributed to differences in woodland attributes and susceptibility to fish colonization. Furthermore, agricultural modification of prairie habitats in South-central Florida may benefit amphibian communities, particularly woodland-dwelling species that are unable to coexist with predatory fish. From a conservation standpoint, temporary wetlands proximal to woodland areas and isolated from permanent water sources appear to be most important to amphibians. In addition, the high tadpole densities attained in these wetlands suggest that these wetlands serve as biological hotspots within the landscape, and their benefits extend into the adjacent terrestrial matrix. Further research efforts are needed to quantify the biological productivity of these systems and determine spatial dynamics of anurans in surrounding terrestrial habitats.

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

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In order to maintain pond-breeding amphibian species richness, it is important to understand how both natural and anthropogenic disturbances affect species assemblages and individual species distributions both at the scale of individual ponds and at a larger landscape scale. The goal of this project was to investigate what characteristics of ponds and the surrounding wetland landscape were most effective in predicting pond-breeding species richness and the individual occurrence of wood frog (Rana sylvatica), bullfrog (Rana catesbeiana) and pickerel frog (Rana palustris) breeding sites in a beaver-modified landscape and how this landscape has changed over time. The wetland landscape of Acadia National Park was historically modified by the natural disturbance cycles of beaver (Castor cazadensis), and since their reintroduction to the island in 1921, beaver have played a large role in creating and maintaining palustrine wetlands. In 2000 and 2001, I studied pond-breeding amphibian assemblages at 71 palustrine wetlands in Acadia National Park, Mount Desert Island, Maine. I determined breeding presence of 7 amphibian species and quantified 15 variables describing local pond conditions and characteristics of the wetland landscape. I developed a priori models to predict sites with high amphibian species and used model selection with Akaike's Information Criterion (AIC) to identify important variables. Single species models were also developed to predict wood frog, bullfrog and pickerel frogs breeding presence. The variables for wetland connectivity by stream corridors and the presence of beaver disturbance were the most effective variables to predict sites with high amphibian richness. Wood frog breeding was best predicted by local scale variables describing temporary, fishless wetlands and the absence of active beaver disturbance. Abandoned beaver sites provided wood frog breeding habitat (70%) in a similar proportion to that found in non beaver-influenced sites (79%). In contrast, bullfrog breeding presence was limited to active beaver wetlands with fish and permanent water, and 80% of breeding sites were large (≥2ha in size). Pickerel frog breeding site selection was predicted best by the connectivity of sites in the landscape by stream corridors. Models including the presence of beaver disturbance, greater wetland perimeter and greater depth were included in the confidence set of pickerel frog models but showed considerably less support. Analysis of historic aerial photographs showed an 89% increase in the total number of ponded wetlands available in the landscape between the years of 1944 and 1997. Beaver colonization generally converted forested wetlands and riparian areas to open water and emergent wetlands. Temporal colonization of beaver wetlands favored large sites low in the watersheds and sites that were impounded later were generally smaller, higher in the watershed, and more likely to be abandoned. These results suggest that beaver have not only increased the number of available breeding sites in the landscape for pond-breeding amphibians, but the resulting mosaic of active and abandoned beaver wetlands also provides suitable breeding habitat for species with differing habitat requirements.

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Our main goal was to determine if fish distribution and adundance in temporary wetlands were shaped primarily by large-scale (landscape) or small-scale (local) characteristics and to investigate the influence of cattle ranching on fish assemblages. A total of 24 temporary ponds were selected at the Kissimmee Prairie Sanctuary and the Mac- Arthur Agro-Ecology Research Center. Each wetland was sampled for fish using throw traps and dip nets during 1999. Landscape processes (connectivity to permanent water bodies) predominately influenced fish assemblages, although local processes (depth–hydroperiod) were also important. Furthermore, no colonizing species went locally extinct before wetlands began to dry. Our findings suggest that large-scale processes that influence colonization dynamics are of more importance than small-scale processes that influence extinction dynamics. Finally, hydrological changes (ditching) associated with agriculture (cattle ranching) have adversely affected temporary wetland fish assemblages by reducing wetland hydroperiods and connectivity.

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The landscape structure of emergent wetlands in undeveloped portions of the southeastern coastal Everglades is comprised of two distinct components: scattered forest fragments, or tree islands, surrounded by a low matrix of marsh or shrub-dominated vegetation. Changes in the matrix, including the inland transgression of salt-tolerant mangroves and the recession of sawgrass marshes, have been attributed to the combination of sea level rise and reductions in fresh water supply. In this study we examined concurrent changes in the composition of the region’s tree islands over a period of almost three decades. No trend in species composition toward more salt-tolerant trees was observed anywhere, but species characteristic of freshwater swamps increased in forests in which fresh water supply was augmented. Tree islands in the coastal Everglades appear to be buffered from some of the short term effects of salt water intrusion, due to their ability to build soils above the surface of the surrounding wetlands, thus maintaining mesophytic conditions. However, the apparent resistance of tree islands to changes associated with sea level rise is likely to be a temporary stage, as continued salt water intrusion will eventually overwhelm the forests’ capacity to maintain fresh water in the rooting zone.

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Movement strategies of small forage fish (<8 cm total length) between temporary and permanent wetland habitats affect their overall population growth and biomass concentrations, i.e., availability to predators. These fish are often the key energy link between primary producers and top predators, such as wading birds, which require high concentrations of stranded fish in accessible depths. Expansion and contraction of seasonal wetlands induce a sequential alternation between rapid biomass growth and concentration, creating the conditions for local stranding of small fish as they move in response to varying water levels. To better understand how landscape topography, hydrology, and fish behavior interact to create high densities of stranded fish, we first simulated population dynamics of small fish, within a dynamic food web, with different traits for movement strategy and growth rate, across an artificial, spatially explicit, heterogeneous, two-dimensional marsh slough landscape, using hydrologic variability as the driver for movement. Model output showed that fish with the highest tendency to invade newly flooded marsh areas built up the largest populations over long time periods with stable hydrologic patterns. A higher probability to become stranded had negative effects on long-term population size, and offset the contribution of that species to stranded biomass. The model was next applied to the topography of a 10 km × 10 km area of Everglades landscape. The details of the topography were highly important in channeling fish movements and creating spatiotemporal patterns of fish movement and stranding. This output provides data that can be compared in the future with observed locations of fish biomass concentrations, or such surrogates as phosphorus ‘hotspots’ in the marsh.

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This short paper presents a means of capturing non spatial information (specifically understanding of places) for use in a Virtual Heritage application. This research is part of the Digital Songlines Project which is developing protocols, methodologies and a toolkit to facilitate the collection and sharing of Indigenous cultural heritage knowledge, using virtual reality. Within the context of this project most of the cultural activities relate to celebrating life and to the Australian Aboriginal people, land is the heart of life. Australian Indigenous art, stories, dances, songs and rituals celebrate country as its focus or basis. To the Aboriginal people the term “Country” means a lot more than a place or a nation, rather “Country” is a living entity with a past a present and a future; they talk about it in the same way as they talk about their mother. The landscape is seen to have a spiritual connection in a view seldom understood by non-indigenous persons; this paper introduces an attempt to understand such empathy and relationship and to reproduce it in a virtual environment.

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The notion of designing with change constitutes a fundamental and foundational theoretical premise for much of what constitutes landscape architecture, notably through engagement with ecology, particularly since the work of Ian McHarg in the 1960s and his key text Design with Nature. However, while most if not all texts in landscape architecture would cite this engagement of change theoretically, few go any further than citation, and when they do their methods seem fixated on utilising empirical, quantitative scientific tools for doing so, rather than the tools of design, in an architectural sense, as implied by the name of the discipline, landscape architecture.

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The picturesque aesthetic in the work of Sir John Soane, architect and collector, resonates in the major work of his very personal practice – the development of his house museum, now the Soane Museum in Lincoln’s Inn Fields in London. Soane was actively involved with the debates, practices and proponents of picturesque and classical practices in architecture and landscape and his lectures reveal these influences in the making of The Soane, which was built to contain and present diverse collections of classical and contemporary art and architecture alongside scavenged curiosities. The Soane Museum has been described as a picturesque landscape, where a pictorial style, together with a carefully defined itinerary, has resulted in the ‘apotheosis of the Picturesque interior’. Soane also experimented with making mock ruinscapes within gardens, which led him to construct faux architectures alluding to archaeological practices based upon the ruin and the fragment. These ideas framed the making of interior landscapes expressed through spatial juxtapositions of room and corridor furnished with the collected object that characterise The Soane Museum. This paper is a personal journey through the Museum which describes and then reviews aspects of Soane’s work in the context of contemporary theories on ‘new’ museology. It describes the underpinning picturesque practices that Soane employed to exceed the boundaries between interior and exterior landscapes and the collection. It then applies particular picturesque principles drawn from visiting The Soane to a speculative project for a house/landscape museum for the Oratunga historic property in outback South Australia, where the often, normalising effects of conservation practices are reviewed using minimal architectural intervention through a celebration of ruinous states.

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Resulting from a series of student-run 'Edge' conferences that have been held in Australia and New Zealand (beginning at RMIT in 1983), The Mesh Book is a collection of essays grouped into themes of Invisible Infrastructures (systems of belief), Immanent Infrastructures (natural systems) and Present Infrastructures (roads and services). Ranging from esoteric discussions to analytical case studies, the book assembles a broad spectrum of ideas on the landscape within the context of Australia and a contemporary study of place.