823 resultados para Landscape Ordination
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A recent debate has contrasted two conservation strategies in agricultural landscapes; either ""land sparing`` farm development combining intensive production practices with forest set-asides, or ""wildlife-friendly`` farming with greater on-farm habitat value but lower yields. We argue that in established mosaic landscapes including old cacao production regions where natural forest has already been reduced to relatively small fragments, a combination of both strategies is needed to conserve biodiversity. After reviewing the evidence for the insufficiency of either strategy alone if applied to such landscapes, the paper focuses on the cacao production landscape of southern Bahia, Brazil, once the world`s second largest cacao producer. Here, small remaining areas of Atlantic Forest are embedded in a matrix dominated by traditional cacao agroforests, resulting in a landscape mosaic that has proven favorable to the conservation of the region`s high biodiversity. We show that current land use dynamics and public policies pose threats but also offer opportunities to conservation and describe a three- pronged landscape conservation strategy, consisting of (i) expansion of the protected areas system, (ii) promotion of productive yet biodiversity-friendly cacao farming practices, and (iii) assistance to land users to implement legally mandated on-farm reserves and voluntary private reserves. We discuss recent experiences concerning the implementation of this strategy, discuss likely future scenarios, and reflect on the applicability of the Bahian experience to biodiversity rich cacao production regions elsewhere in the tropics.
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Brazil`s State of Sao Paulo Research Foundation
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This field report presents fieldwork undertaken in Hjaltadalur, Skagafjördur, northern Iceland during summer 2010. The main aim was to initiate coring in selected mires in order to determine the composition of organic material and sediments in the mires, sub-sample for sedimentological and palaeoecological analyses, and initiate advanced landscape analysis of Hjaltadalur. Three mires were selected for sediments coring in Hjaltadalur: Ástunga close to Kolkóus, Hólakot at Viðvik, and Hólar. All three represented a landscape transect in NW to SE direction, from close to the coast to valley interior, i.e. close to the old settlement at Hólar.
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The purpose of my Senior Scholar project was to create a series of sculptures that are based on the interaction of natural forms within a selected landscape setting. I hope to convey a sense of how I view and interpret the landscape and to create works that stimulate a sense of wonder in the mind of the viewer. This fascination, perhaps even obsession, with the power of the landscape has kept me going throughout the year. As a source of ideas and imagery, the landscape can never be depleted. There will always be new combinations of landscape elements, different light conditions, and changing seasons to provide me with fresh ideas. Research for the project took me to many different places, be it my trip to Monhegan Island or driving to New York City to study the cityscape. I began the year working in steel and plaster, combining the two in works that explore the interaction between living tree roots and inanimate rocks. This led to a series entitled Landscape Recollections, comprised of welded steel forms housed in protective wooden boxes and lit from inside. After visiting New York City, architecture began to playa role in my work, as seen in the two Roadcut pieces and the Cathedral Woods series. Roadcut #1 and Roadcut #2 explore the relationship between a man-made road and the landscape that lies beneath and around it. The Cathedral Woods pieces incorporate architecture in a more abstract manner, using imagery derived from Gothic cathedrals to convey a sense of quiet peacefulness. The soaring verticality of Gothic architecture integrates with the tall tree forms in each piece, enabling me to intertwine these two elements into one another and create a harmonious relationship between architecture and nature. Throughout the year I have kept a sketchbook in which I draw from life, jot down ideas, and take notes on how the project is progressing. I have also completed several large charcoal drawings of my sculptures in which I explore different ways of viewing the steel forms. I am grateful to have had the opportunity to undertake this project, as it has been a very difficult but rewarding process of observing, interpreting, and manifesting the landscape according to my personal vision and experiences.
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We study a model of sovereign debt crisis that combines problems of creditor coordination and debtor moral hazard. Solving the sovereign debtor's incentives leads to excessive 'rollover failure' by creditors when sovereign default occurs. We discuss how the incidence of crises might be reduced by international sovereign bankruptcy procedures and relate this to the current debate on revising international financial architecture. Paper prepared for Bank of England Conference on "The Role of the Official and Private Sectors in Resolving International Financial Crises", London, and for the Latin American Meeting of the Econometric Society, Sao Paolo, Brazil. (Preliminary draft circulated for comments, please do not cite without reference to the authors).
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The aim of this thesis was to evaluate historical change of the landscape of Madeira Island and to assess spatial and temporal vegetation dynamics. In current research diverse “retrospective techniques”, such as landscape repeat photography, dendrochronology, and research of historical records were used. These, combined with vegetation relevés, aimed to gather information about landscape change, disturbance history, and vegetation successional patterns. It was found that landscape change, throughout 125 years, was higher in the last five decades manly driven by farming abandonment, building growth and exotic vegetation coverage increase. Pristine vegetation was greatly destroyed since early settlement and by the end of the nineteenth century native vegetation was highly devastated due to recurrent antropogenic disturbances. These actions also helped to block plant succession and to modify floristical assemblages, affecting as well as species richness. In places with less hemeroby, although significant growth of vegetation of lower seral stages was detected, the vegetation of most mature stages headed towards unbalance between recovery and loss, being also very vulnerable to exotic species encroachment. Recovery by native vegetation also occurred in areas formerly occupied by exotic plants and agriculture but it was almost negligible. Vegetation recovery followed the successional model currently proposed, attesting the model itself. Yet, succession was slower than espected, due to lack of favourable conditions and to recurrent disturbances. Probable tempus of each seral stage was obtained by growth rates of woody taxa estimated through dendrochronology. The exotic trees which were the dominant trees in the past (Castanea sativa and Pinus pinaster) almost vanished. Eucalyptus globulus, the current main tree of the exotic forest is being replaced by other cover types as Acacia mearnsii. The latter, along with Arundo donax, Cytisus scoparius and Pittosporum undulatum are currently the exotic species with higher invasive behaviour. However, many other exotic species have also proved to be highly pervasive and came together with the ones referred above to prevent native vegetation regeneration, to diminish biological diversity, and to block early successional phases delaying native forest recovery.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The general statement that birds are recorded more often on morning than on afternoon counts is quite common and widespread among ornithologists. Although many investigators have reported temporal variations in bird detections using Point Counts in temperate regions, few researches regarding the same objectives have been conducted in Neotropical habitats or used transect counts as field method. We used transect counts to test the hypothesis that birds are evenly recorded between times of day in a predominantly open Cerrado landscape in southeastern Brazil. Although not always significantly, the number of species and individuals were consistently greater during the morning counts, which corroborates the fact that birds can be more detectable during this time of day. However, a few families as well as a small percentage of species were more likely to be recorded during either one of the two periods we analyzed. Our results suggest that morning counts should detect higher number of both species and individuals in our study area, but specific taxa show distinct patterns of detection which should be acknowledged prior to sampling.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Parrots are the most threatened group of birds in the world, mainly because of the reduction and fragmentation of their natural habitats. However, few studies have investigated the dynamics of parrot populations in disturbed landscapes on a broad scale. In this paper, we studied the ecological interactions of the vulnerable blue-winged macaw (Primolius maracana) in a fragmented landscape surrounding a large protected park in southeastern Brazil. We sampled 36 forest fragments that varied in size, characteristics, degree of isolation and type of surrounding matrix in order to assess the importance of habitat features on the maintenance of these birds. Blue-winged macaws were recorded in 70% of the satellite remnants that were sampled, which included large and small blocks of forest. These areas were used as sites for feeding, nesting or overnight rests, and also provided connectivity for birds' displacements. However, the frequency of macaw visits varied among the remnants, and this was related to habitat features such as patch size, human use of surrounding land, and the proximity to the protected park, to urban areas and to the birds' roosting areas. In general, landscape-scale parameters explained more of the variation in the frequency of visits by macaws than did patch-scale parameters. These results demonstrate the importance of landscape mosaics for the survival of blue-winged macaws.
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To investigate the movement of seeds transported by fruit-eating birds in an agricultural, fragmented landscape of the Atlantic forest of southeast Brazil, I asked which bird species are the main seed dispersers in such environment, and how they use the available habitats (small forest fragments, forest thickets, live fences, isolated trees, and active pastures) where they are most likely to drop the seeds they swallow the relative importance of fruit-eating birds as seed vectors was evaluated based on the number of fruit species eaten, the number of visits, and visitation rate to fruiting plants. Habitat use was accessed by recording the habitats where birds were seen or heard during walks conducted throughout the study area. Sixteen plant species were observed during 308.3 plant-hours. Forty-one bird species were observed eating fruits in a total of 830 visits to fruiting plants. Sayaca Tanagers (Thraupis sayaca) and Pale-breasted Thrushes (Turdus leucomelas) ate the greatest number of fruit species, were the most frequent plant visitors in terms of number and rate of visits, and had a broad range of habitat use. These two species and the Rusty-margined Guan (Penelope superciliaris), which is able to swallow large fruits with large seeds that smaller bird species cannot cat, likely have a great contribution to the movement of seeds throughout this highly degraded landscape.