			Home About us Contact

Deforestation

Distribution by Scientific Domains

Life Sciences	55%
Humanities and Social Sciences	22%
Earth and Environmental Science	15%
Chemistry	2%
2 Other Domains	6%

Distribution within Life Sciences

Conservation Science	32%
Ecology & Organismal Biology	21%
Evolution	10%
9 Other Subdomains	37%

Selected Abstracts

Malaria Linked to Deforestation

CONSERVATION, Issue 2 2006
Article first published online: 18 MAY 200
No abstract is available for this article. [source]

Development Discourses and Peasant,Forest Relations: Natural Resource Utilization as Social Process

DEVELOPMENT AND CHANGE, Issue 1 2000
Anja Nygren
This article analyses the changing role of forests and the practices of peasants toward them in a Costa Rican rural community, drawing on an analytical perspective of political ecology, combined with cultural interpretations. The study underlines the complex articulation of local processes and global forces in tropical forest struggles. Deforestation is seen as a process of development and power involving multiple social actors, from politicians and development experts to a heterogeneous group of local peasants. The local people are not passive victims of global challenges, but are instead directly involved in the changes concerning their production systems and livelihood strategies. In the light of historical changes in natural resource utilization, the article underlines the multiplicity of the causes of tropical deforestation, and the intricate links between global discourses on environment and development and local forest relations. [source]

History of Deforestation and Reforestation in the Dinaric Karst

GEOGRAPHICAL RESEARCH, Issue 1 2009
ANDREJ KRANJC
Abstract The term karst derives from the Kras plateau, which is in the northwestern part of the area now known as the Dinaric Karst. The landscape consists mostly of Mesozoic carbonate rocks and stretches along the Adriatic Sea coast for a distance of 600 km. Although the region lies parallel to the sea, the Mediterranean temperature influence is limited to a narrow coastal belt, except for the amount of precipitation, which can reach 5000 mm yr,1. Forests belonging to the Mediterranean and Euro-Siberian , North American region, covered the primary Dinaric Karst. Human deforestation of the Karst began during the Neolithic period, 6500,6000 BC. Throughout history there have been two main reasons for deforestation; economic (the requirements of new land, pastures, timber use and trade), and social (local increases in population, mass migration, wars, raids). Mankind's perception of forest protection and preservation can be traced through documents going back to the 12th century. Reforestation is mentioned in some of them, but successful reforestation did not begin until the 1850s. Nowadays dense natural forests, extensive forest plantations, dry karst shrublands and also completely barren karst areas can all be found on the Dinaric Karst. [source]

Linking Spatial Pattern and Ecological Responses in Human-Modified Landscapes: The Effects of Deforestation and Forest Fragmentation on Biodiversity

GEOGRAPHY COMPASS (ELECTRONIC), Issue 4 2009
John A. Kupfer
Studies of forest loss and fragmentation provide clear examples of the linkages between ecological pattern and process. Reductions in forest area lead to higher within-patch extinction rates, the eventual loss of area-sensitive species, and declines in species richness and diversity. Forest loss also results in increased isolation of remnants, lower among-patch immigration rates, and less ,rescue' from surrounding populations. Specific responses, however, are sometimes counterintuitive because they depend on life-history tradeoffs that influence population dynamics and species co-existence in heterogeneous landscapes, not just forest remnants. Thus, while fragmentation generally favours r-selected, generalist strategies, such as high dispersal and a wide niche breadth, ecological outcomes may be confounded by species-specific responses to conditions in the human-dominated matrix and the ways in which forest edges shape cross-landscape movements. Given that pressures on global forestlands continue to intensify due to growing population sizes, economic pressures, and needs for space and resources, successfully maintaining or restoring species will necessitate a combination of short- and long-term actions that address both habitat protection and restoration. Doing so will require an interdisciplinary approach that gives adequate attention to the manners by which forest loss and fragmentation affect population dynamics through changes in forest area, isolation, habitat quality, matrix properties, and edge effects as well as the synergistic interactions of fragmentation with climate change, human-altered disturbance regimes, species interactions and other drivers of species population declines. [source]

Assessing the impact of deforestation and climate change on the range size and environmental niche of bird species in the Atlantic forests, Brazil

JOURNAL OF BIOGEOGRAPHY, Issue 7 2010
Bette A. Loiselle
Abstract Aim, Habitat loss and climate change are two major drivers of biological diversity. Here we quantify how deforestation has already changed, and how future climate scenarios may change, environmental conditions within the highly disturbed Atlantic forests of Brazil. We also examine how environmental conditions have been altered within the range of selected bird species. Location, Atlantic forests of south-eastern Brazil. Methods, The historical distribution of 21 bird species was estimated using Maxent. After superimposing the present-day forest cover, we examined the environmental niches hypothesized to be occupied by these birds pre- and post-deforestation using environmental niche factor analysis (ENFA). ENFA was also used to compare conditions in the entire Atlantic forest ecosystem pre- and post-deforestation. The relative influence of land use and climate change on environmental conditions was examined using analysis of similarity and principal components analysis. Results, Deforestation in the region has resulted in a decrease in suitable habitat of between 78% and 93% for the Atlantic forest birds included here. Further, Atlantic forest birds today experience generally wetter and less seasonal forest environments than they did historically. Models of future environmental conditions within forest remnants suggest generally warmer conditions and lower annual variation in rainfall due to greater precipitation in the driest quarter of the year. We found that deforestation resulted in a greater divergence of environmental conditions within Atlantic forests than that predicted by climate change. Main conclusions, The changes in environmental conditions that have occurred with large-scale deforestation suggest that selective regimes may have shifted and, as a consequence, spatial patterns of intra-specific variation in morphology, behaviour and genes have probably been altered. Although the observed shifts in available environmental conditions resulting from deforestation are greater than those predicted by climate change, the latter will result in novel environments that exceed temperatures in any present-day climates and may lead to biotic attrition unless organisms can adapt to these warmer conditions. Conserving intra-specific diversity over the long term will require considering both how changes in the recent past have influenced contemporary populations and the impact of future environmental change. [source]

Deforestation and land use change: sparse data environments

AGRICULTURAL ECONOMICS, Issue 3 2002
Gerald C. Nelson
Abstract Understanding determinants of land use in developing countries has become a priority for researchers and policy makers with a wide range of interests. For the vast majority of these land use issues, the location of change is as important as its magnitude. This overview paper highlights new economic approaches to modeling land use determinants that combine non-traditional data sources with novel economic models and econometric techniques. A key feature is that location is central to the analysis. All data elements include an explicit location attribute, estimation techniques include the potential for complications from spatial effects, and results are location-specific. The paper reviews the theory underlying these models. Since this paper is intended to provide the potential new researcher with an introduction to the challenges of this analysis, we present an overview of how remotely-sensed data are collected and processed, describe key GIS concepts and identify sources of data for this type of econometric analysis. Finally, selected papers using these techniques are reviewed. [source]

Mapping and monitoring land degradation risks in the Western Brazilian Amazon using multitemporal Landsat TM/ETM+ images

LAND DEGRADATION AND DEVELOPMENT, Issue 1 2007
D. Lu
Abstract Mapping and monitoring land degradation in areas under human-induced stresses have become urgent tasks in remote sensing whose importance has not yet been fully appreciated. In this study, a surface cover index (SCI) is developed to evaluate and map potential land degradation risks associated with deforestation and accompanying soil erosion in a Western Brazilian Amazon rural settlement study area. The relationships between land-use and land-cover (LULC) types and land degradation risks as well as the impacts of LULC change on land degradation are examined. This research indicates that remotely sensed data can be effectively used for identification and mapping of land degradation risks and monitoring of land degradation changes in the study area. Sites covered by mature forest and advanced successional forests have low land degradation risk potential, while some types of initial successional forests, agroforestry/perennial agriculture and pasture have higher risk potential. Deforestation and associated soil erosion are major causes leading to land degradation, while vegetation regrowth reduces such problems. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Linking Amazonian secondary succession forest growth to soil properties

LAND DEGRADATION AND DEVELOPMENT, Issue 4 2002
D. Lu
Abstract The Amazon Basin has suffered extensive deforestation in the past 30 years. Deforestation typically leads to changes in climate, biodiversity, hydrological cycle, and soil degradation. Vegetation succession plays an important role in soil restoration through accumulation of vegetation biomass and improved soil/plant interaction. However, relationships between succession and soil properties are not well known. For example, how does vegetation succession affect nutrient accumulation? Which soil factors are important in influencing vegetation growth? What is the best way to evaluate soil fertility in the Amazon basin? This paper focuses on the interrelationships between secondary succession and soil properties. Field soil sample data and vegetation inventory data were collected in two regions of Brazilian Amazonia (Altamira and Bragantina). Soil nutrients and texture were analyzed at successional forest sites. Multiple regression models were used to identify the important soil properties affecting vegetation growth, and a soil evaluation factor (SEF) was developed for evaluating soil fertility in Alfisols, Ultisols, and Oxisols, which differ in the ways they affect vegetation growth. For example, the upper 40,cm of soil is most important for vegetation growth in Alfisols, but in Ultisols and Oxisols deeper horizons significantly influence vegetation growth rates. Accumulation of vegetation biomass increased soil fertility and improved soil physical structure in Alfisols but did not completely compensate for the nutrient losses in Ultisols and Oxisols; however, it significantly reduced the rate of nutrient loss. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Conservation education in Madagascar: three case studies in the biologically diverse island-continent,

AMERICAN JOURNAL OF PRIMATOLOGY, Issue 5 2010
Francine L. Dolins
Abstract Few Malagasy children and adults are aware of the rare and unique fauna and flora indigenous to their island-continent, including flagship lemur species. Even the Malagasy ancestral proverbs never mentioned lemurs, but these same proverbs talked about the now extinct hippopotamus. Madagascar's geography, history, and economic constraints contribute to severe biodiversity loss. Deforestation on Madagascar is reported to be over 100,000 ha/year, with only 10,15% of the island retaining natural forest [Green & Sussman, 1990]. Educating children, teacher-training, and community projects about environmental and conservation efforts to protect the remaining natural habitats of endangered lemur species provide a basis for long-term changes in attitudes and practices. Case studies of three conservation education projects located in different geographical regions of Madagascar, Centre ValBio, Madagacar Wildlife Conservation Alaotra Comic Book Project, and The Ako Book Project, are presented together with their ongoing stages of development, assessment, and outcomes. We argue that while nongovernmental organizational efforts are and will be very important, the Ministry of Education urgently needs to incorporate biodiversity education in the curriculum at all levels, from primary school to university. Am. J. Primatol. 72:391,406, 2010. © 2009 Wiley-Liss, Inc. [source]

Conservation Challenges for the Austral and Neotropical America Section

CONSERVATION BIOLOGY, Issue 4 2009
GERARDO CEBALLOS
América Austral y Neotropical; América Latina; desarrollo de capacidades Abstract:,The Austral and Neotropical America (ANA) section of the Society for Conservation Biology includes a vast territory with some of the largest relatively pristine ecosystems in the world. With more than 573 million people, the economic growth of the region still depends strongly on natural resource exploitation and still has high rates of environmental degradation and biodiversity loss. A survey among the ANA section membership, with more than 700 members, including most of the section's prominent ecologists and conservationists, indicates that lack of capacity building for conservation, corruption, and threats such as deforestation and illegal trade of species, are among the most urgent problems that need to be addressed to improve conservation in the region. There are, however, strong universities and ecology groups taking the lead in environmental research and conservation, a most important issue to enhance the ability of the region to solve conservation and development conflicts. Resumen:,La sección América Austral y Neotropical (AAN) de la Sociedad para la Biología de la Conservación incluye un vasto territorio con unos de los ecosistemas relativamente prístinos más extensos del mundo. Con más de 573 millones de habitantes, el crecimiento económico de la región aun depende fuertemente de la explotación de recursos naturales y aún tiene altas tasas de degradación ambiental y pérdida de biodiversidad. Un sondeo de la membresía de la sección AAN, con más de 700 miembros, incluyendo la mayoría de los ecólogos y conservacionistas más prominentes de la sección, indica que la carencia de desarrollo de capacidades para la conservación, la corrupción y amenazas como la deforestación y el comercio ilegal de especies, son algunos de los problemas que requieren ser atendidos más urgentemente para mejorar la conservación en la región. Sin embargo, hay universidades y grupos ecológicos que están tomando el liderazgo en investigación ambiental y conservación, un tema importante para mejorar la habilidad de la región para resolver conflictos de conservación y desarrollo. [source]

Conservation of Brazilian Amphibians

CONSERVATION BIOLOGY, Issue 3 2005
DÉBORA L. SILVANO
The Brazilian Official List of Threatened Species and the results of a workshop for the Global Amphibian Assessment indicate that 26 species are threatened. The majority of these occur in the Atlantic Forest, one of the world's biodiversity hotspots. The main threat to amphibians is the destruction of their habitats through deforestation, conversion into agricultural land, mining, wildfires, and infrastructure development and urbanization. In Brazil little is known about other causes of amphibian decline observed worldwide, such as pesticides, infectious diseases, climate change, invasive species, or wildlife trade. Brazilian conservation policies include such important legal instruments as the Official List of Threatened Species and the selection of priority areas for conservation measures in all of Brazil's major biomes. Although there is little information on geographic distributions and the natural history and ecology of the large majority of the currently recognized species, a number of important regional studies for amphibian conservation are under way. New species are discovered each year. Resumen:,Brasil es el líder mundial en diversidad de anfibios, con 765 especies, la mayoría de las cuales han sido descritas en los últimos 40 años. La Lista Brasileña Oficial de Especies Amenazadas y los resultados de un taller para la Evaluación Global de Anfibios indican que 26 especies están amenazadas, la mayoría de ellas ocurre en el Bosque Atlántico, uno de los sitios de importancia para la biodiversidad global. La principal amenaza a los anfibios es la destrucción de sus hábitats por la deforestación, conversión a tierras agrícolas, minería, fuego no controlado, desarrollo de infraestructura y urbanización. En Brasil se conoce poco sobre otras causas de la declinación de anfibios observadas en todo el mundo, como pesticidas, enfermedades infecciosas, cambio climático, especies invasoras o comercio de vida silvestre. Las políticas Brasileñas de conservación incluyen importantes instrumentos legales como la Lista Oficial de Especies Amenazadas y la selección de áreas prioritarias para la conservación en todos lo biomas principales de Brasil. Existe escasa información sobre la distribución geográfica y la historia natural y ecología de la gran mayoría de las especies reconocidas actualmente, aunque se está desarrollando un importante número de estudios regionales para la conservación de anfibios. Cada año se descubren nuevas especies. [source]

Mexico's Community-Managed Forests as a Global Model for Sustainable Landscapes

CONSERVATION BIOLOGY, Issue 3 2003
David Barton Bray
On the other hand, conservationists have declared that the only way to stem the tide of deforestation is to place as many tracts as possible under strict protection. In this context, Mexico presents a national laboratory for studying the social and ecological benefits of delivering forests to local people. As a little-noticed result of the Mexican Revolution in the second decade of the twentieth century, well over half of the forests of Mexico were placed in community-held lands. In historic struggles that passed through several phases, most of these communities have now gained substantial control over the use of their forests. Because of the substantial degree of social capital in rural forms of organization in Mexico, this control of forest resources has led to an estimated 290,479 community forest enterprises ( CFEs ), through which communities are producing timber on their own lands. New studies are beginning to suggest that important gains in both social and economic justice, good forest management, and biodiversity protection are resulting from the actions of these CFEs. As more forests globally are being devolved to local communities, it is important to carry out more research on the Mexican model of community forest management for timber production. Resumen: Investigadores preocupados por el manejo sostenible de bosques en los trópicos han argumentado que el camino para una custodia mas efectiva de los recursos forestales es la transferencia de la responsabilidad a las comunidades locales que obtienen sustento de ellos. Por otro lado, conservacionistas han declarado que la única manera de detener la ola de deforestación es colocar bajo protección estricta tantas regiones como sea posible. En este contexto, México representa un laboratorio para el estudio de los beneficios sociales y ecológicos de entregar los bosques a los habitantes locales. Como un resultado poco conocido de la Revolución Mexicana, en la segunda década del siglo veinte, más de la mitad de los bosques de México se ubicaban en tierras que estaban en manos de las comunidades. Las comunidades forestales han atravesado por distintas etapas de conflicto, tras la cuáles han obtendio un control sustancial de los usos de sus bosques. Debido al nivel considerable de capital social en formas de organización rural en México, este control de los recursos forestales ha conducido a la integración de entre 290,479 empresas forestales comunitarias ( EFC ), en las que las comunidades están produciendo madera en sus propias tierras. Nuevos estudios están comenzando a sugerir que se están produciendo ganancias importantes en las acciones de estas EFC están generando beneficios importantes, tanto en lo que se refiere a justicia social como económica, la administración correcta de bosques y la protección de la biodiversidad. A medida en que se deleguen mayores extensiones de bosques a comunidades locales, es importante llevar a cabo más investigación sobre el modelo mexicano de manejo comunitario de bosques para la producción de forestal maderable. [source]

Habitat Loss and Extinction in the Hotspots of Biodiversity

CONSERVATION BIOLOGY, Issue 4 2002
Thomas M. Brooks
None of these hotspots have more than one-third of their pristine habitat remaining. Historically, they covered 12% of the land's surface, but today their intact habitat covers only 1.4% of the land. As a result of this habitat loss, we expect many of the hotspot endemics to have either become extinct or,because much of the habitat loss is recent,to be threatened with extinction. We used World Conservation Union [ IUCN ] Red Lists to test this expectation. Overall, between one-half and two-thirds of all threatened plants and 57% of all threatened terrestrial vertebrates are hotspot endemics. For birds and mammals, in general, predictions of extinction in the hotspots based on habitat loss match numbers of species independently judged extinct or threatened. In two classes of hotspots the match is not as close. On oceanic islands, habitat loss underestimates extinction because introduced species have driven extinctions beyond those caused by habitat loss on these islands. In large hotspots, conversely, habitat loss overestimates extinction, suggesting scale dependence (this effect is also apparent for plants). For reptiles, amphibians, and plants, many fewer hotspot endemics are considered threatened or extinct than we would expect based on habitat loss. This mismatch is small in temperate hotspots, however, suggesting that many threatened endemic species in the poorly known tropical hotspots have yet to be included on the IUCN Red Lists. We then asked in which hotspots the consequences of further habitat loss (either absolute or given current rates of deforestation) would be most serious. Our results suggest that the Eastern Arc and Coastal Forests of Tanzania-Kenya, Philippines, and Polynesia-Micronesia can least afford to lose more habitat and that, if current deforestation rates continue, the Caribbean, Tropical Andes, Philippines, Mesoamerica, Sundaland, Indo-Burma, Madagascar, and Chocó,Darién,Western Ecuador will lose the most species in the near future. Without urgent conservation intervention, we face mass extinctions in the hotspots. Resumen: Casi la mitad del total de plantas vasculares del mundo y un tercio de los vertebrados terrestres son endémicos en 25 "áreas críticas" para la biodiversidad, cada una de las cuales tiene por lo menos 1500 especies de plantas endémicas. En ninguno de estos sitios permanece más de un tercio de su hábitat prístino. Históricamente, cubrían 12% de la superficie terrestre, pero en la actualidad su hábitat intacto cubre solo 1.4% del terreno. Como resultado de esta pérdida de hábitat esperamos que muchas de las especies endémicas a estos sitios estén extintas o , porque la pérdida de hábitat es reciente , se encuentren amenazadas de extinción. Utilizamos Listas Rojas de UICN para comprobar esta predicción. En general, entre la mitad y dos tercios de las plantas amenazadas y el 57% de los vertebrados terrestres amenazados son endémicos de áreas críticas para la biodiversidad. Para aves y mamíferos en general, las predicciones de extinción en las áreas críticas para la biodiversidad, basadas en la pérdida de hábitat, coinciden con el número de especies consideradas extintas o amenazadas independientemente. En dos clases de áreas críticas para la biodiversidad la coincidencia no es muy grande. En islas oceánicas, la pérdida de hábitat subestima la extinción porque las especies introducidas han causado más extinciones que las producidas por la reducción del hábitat. Por lo contrario, la pérdida de hábitat sobrestima la extinción en áreas críticas para la biodiversidad extensas, lo que sugiere una dependencia de escala (este efecto también es aparente para plantas). Para reptiles, anfibios y plantas mucho menos especies endémicas son consideradas amenazadas o extintas por pérdida de hábitat. Sin embargo, esta discordancia es pequeña en áreas críticas para la biodiversidad en zonas templadas templadas, lo que sugiere que muchas especies endémicas amenazadas en las poco conocidas áreas críticas para la biodiversidad en zonas tropicales aun están por incluirse en las Listas Rojas. Posteriormente nos preguntamos en que áreas críticas para la biodiversidad serían más serias las consecuencias de una mayor pérdida de hábitat (absoluta o con las tasas actuales de deforestación). Nuestros resultados sugieren que el Arco Oriental y los Bosques Costeros de Tanzania/Kenia, Filipinas, Polinesia/Micronesia no pueden soportar mayores pérdidas y que, si continúan las tasas de deforestación actuales, el Caribe, Andes Tropicales, Filipinas, Mesoamérica, Sundaland, Indo-Burma, Madagascar y Chocó/Darién/Ecuador Occidental perderán más especies en el futuro. Sin acciones urgentes de conservación, habrá extinciones masivas en las áreas críticas para la biodiversidad. [source]

Conservation Biology Framework for the Release of Wild-Born Orphaned Chimpanzees into the Conkouati Reserve, Congo

CONSERVATION BIOLOGY, Issue 5 2001
Caroline E. G. Tutin
Release of captive individuals is complex and controversial, however, particularly when risks are potentially high, as in the case of orphaned apes. We describe the decision-making process that led to the successive release of 20 wild-born orphan chimpanzees ( Pan troglodytes troglodytes) into the Conkouati Reserve in the Republic of Congo. Recommendations of the Reintroduction Specialist Group of the World Conservation Union's Species Survival Commission were followed closely. The conservation status, ecology, and behavior of wild chimpanzees; the biological, social, economic and political context of the release site; and the health and genetic status of the candidates for release were all taken into account in the planning and execution of the project. Rigorous post-release monitoring of behavior and health allowed documentation of the outcome. The project was of benefit to the chimpanzees that were released but also brought broad benefits to the site through effective protection from poaching and deforestation, and direct and indirect benefits to local people. The genetic and behavioral diversity of chimpanzees require a variety of conservation strategies to reduce threats and maintain as many viable wild populations as possible. Resumen: El retorno de animales confiscados a sus hábitats nativos es deseable cuando ocasiona una contribución positiva para la conservación de la especie. Sin embargo, la liberación de individuos cautivos es compleja y controversial, particularmente cuando los riesgos son potencialmente altos, como es el caso de los monos huérfanos. Describimos el proceso de toma de decisiones que condujo a la liberación de exitosa de 20 chimpancés silvestres huérfanos ( Pan troglodytes troglodytes) dentro de la Reserva Conkouati de la República de Congo. Las recomendaciones del Grupo de especialistas en reintroducción de la UICN-SSC fueron seguidas de cerca. El estatus de conservación, ecología y conducta de los chimpancés silvestres; el contexto biológico, social, económico y político del sitio de liberación y la salud y estatus genético de los candidatos a ser liberados fueron también tomados en consideración en la planeación y ejecución del proyecto. El monitoreo riguroso post-liberación de la conducta y salud permitió la documentación de los resultados. El proyecto fue benéfico para los chimpancés liberados pero también trajo beneficios amplios al sitio mediante la protección efectiva de la caza fortuita y la deforestación y beneficios directos e indirectos para la población humana local. La diversidad genética y conductual de los chimpancés requiere de una variedad de estrategias de conservación para reducir las amenazas y mantener cuantas poblaciones silvestres viables sean posibles. [source]

Possible Environmental Factors Underlying Amphibian Decline in Eastern Puerto Rico: Analysis of U.S. Government Data Archives

CONSERVATION BIOLOGY, Issue 4 2001
Robert F. Stallard
I examined changes in environmental conditions by examining time-series data sets that extend back at least into the 1980s, a period when frog populations were declining. The data include forest cover; annual mean, minimum, and maximum daily temperature; annual rainfall; rain and stream chemistry; and atmospheric-dust transport. I examined satellite imagery and air-chemistry samples from a single National Aeronautics and Space Administration aircraft flight across the Caribbean showing patches of pollutants, described as thin sheets or lenses, in the lower troposphere. The main source of these pollutants appeared to be fires from land clearing and deforestation, primarily in Africa. Some pollutant concentrations were high and, in the case of ozone, approached health limits set for urban air. Urban pollution impinging on Puerto Rico, dust generation from Africa ( potential soil pathogens), and tropical forest burning ( gaseous pollutants) have all increased during the last three decades, overlapping the timing of amphibian declines in eastern Puerto Rico. None of the data sets pointed directly to changes so extreme that they might be considered a direct lethal cause of amphibian declines in Puerto Rico. More experimental research is required to link any of these environmental factors to this problem. Resumen: Las pasadas tres décadas han visto grandes disminuciones poblacionales de especies de anfibios en altas elevaciones de Puerto Rico oriental, una región única en los trópicos húmedos debido al grado de monitoreo ambiental que se ha llevado a cabo mediante los esfuerzos de las agencias de gobierno de los Estados Unidos. Examiné los cambios en condiciones ambientales mediante el análisis de datos de series de tiempo que se extienden hasta los 1980s, un periodo en el que las poblaciones de ranas estaban declinando. Los datos incluyen cobertura forestal; temperatura diaria media, mínima y máxima anual; precipitación anual; química de la lluvia y arroyos; y el transporte atmosférico de polvo. Examiné imágenes de satélite y muestras de química del aire obtenidos de un solo vuelo de una nave de la NASA a lo largo del Caribe que mostraba parches de contaminantes descritas como capas delgadas de lentes en la inferior troposfera. La mayor fuente de contaminantes parece ser los incendios de tierras clareadas y la deforestación, principalmente en África. Algunas concentraciones de contaminantes fueron altas y en el caso del ozono, se aproximó a los límites de salud establecidos para aire urbano. La contaminación urbana afectando a Puerto Rico, la generación de polvo en África ( patógenos del suelo potenciales) y la quema de bosque tropical (contaminantes gaseosos) han incrementado durante las últimas tres décadas, superponiéndose con el periodo en que oturrieron las disminuciones de anfibios en Puerto Rico oriental. Ninguno de estos conjuntos de datos señaló directamente hacia cambios tan extremos que debieran ser considerados como una causa letal directa de las disminuciones en Puerto Rico. Se requiere de más investigación experimental que vincule a estos factores ambientales con este problema. [source]

Heavy Extinctions of Forest Avifauna in Singapore: Lessons for Biodiversity Conservation in Southeast Asia

CONSERVATION BIOLOGY, Issue 6 2000
Marjorie Castelletta
In Southeast Asia, Singapore, a newly developing country, has had 95% of its native lowland rainforest cleared. Most of the rainforest was lost in the mid- to late-nineteenth century. We compared avifauna checklists from 1923, 1949, and 1998 to determine the extent of extinctions between 1923 and 1998 in Singapore. Of 203 diurnal bird species, 65 were extirpated in Singapore in the past 75 years. Four of these species were nonforest- dependent species, whereas 61 (94%) were forest bird species dependent on the primary or old secondary forest to survive. Twenty-six forest bird species became extinct between 1923 and 1949, whereas 35 forest species disappeared after 1949. We compared the body lengths, feeding guilds, and vertical feeding zones between extinct and extant forest bird species to determine whether extinction patterns were dependent on these characteristics. Larger forest bird species went extinct between 1923 and 1949. Body sizes, however, did not affect the loss of forest bird species between 1949 and 1998. We observed high losses of insectivorous birds; the insectivore-carnivore and insectivore-granivore guilds lost> 80% of the species present in 1923. The highest losses were among birds that fed in the canopy. None of the forest bird species are currently common (>100 individuals/species) within Singapore. Our study shows that more than half the forest avifauna became locally extinct after extensive deforestation. Based on this fact, the countries within Southeast Asia should reconsider their heavy deforestation practices. Resumen: Las consecuencias de la tala rápida del bosque lluvioso sobre la avifauna nativa son poco conocidas. En Asia sudoriental, Singapur, un país en desarrollo, un 95% de su bosque nativo de tierras bajas ha sido talado. La mayoríia del bosque se perdió entre mediados y finales del siglo diecinueve. En este trabajo comparamos las listas de avifauna de 1923, 1949 y 1998 para determinar la extensión de las extinciones en Singapur entre 1923 y 1998. Sesenta y cinco de las 203 especies diurnas de aves fueron extirpadas de Singapur en los últimos 75 años. Cuatro de estas especies fueron especies no dependientes del bosque, mientras que 61 (94%) fueron especies de aves del bosque (especies que dependen del bosque primario o secundario viejo para sobrevivir). Veintiséis de las especies de aves del bosque se extinguieron entre 1923 y 1949, mientras que 35 especies del bosque desaparecieron después de 1949. Comparamos las longitudes del cuerpo, los gremios de alimentación y las zonas de alimentación vertical entre especies de aves de bosque extintas y existentes para determinar si los patrones de extinción fueron dependientes de estas características. Las especies de aves grandes del bosque se extinguieron entre 1923 y 1949. Sin embargo, el tamaño del cuerpo no afectó la pérdida de especies del bosque entre 1949 y 1998. Observamos altas pérdidas de aves insectívoras; los gremios de insectívoros-carnívoros e insectívoros-granívoros perdieron> 80% de las especies que estaban presentes en 1923. Los números más altos de pérdidas fueron de aves que se alimentan en el dosel. Ninguna de las especies de aves del bosque es común en la actualidad (>100 individuos/especie) dentro de Singapur. Nuestro estudio muestra que más de la mitad de la avifauna del bosque se ha extinguido localmente después de una deforestación extensiva. Con base en este hecho, los países dentro de Asia Sudoriental deberían reconsiderar sus prácticas de intensa deforestación. [source]

Advancing a Political Ecology of Global Environmental Discourses

DEVELOPMENT AND CHANGE, Issue 4 2001
W. Neil Adger
In the past decade international and national environmental policy and action have been dominated by issues generally defined as global environmental problems. In this article, we identify the major discourses associated with four global environmental issues: deforestation, desertification, biodiversity use and climate change. These discourses are analysed in terms of their messages, narrative structures and policy prescriptions. We find striking parallels in the nature and structure of the discourses and in their illegibility at the local scale. In each of the four areas there is a global environmental management discourse representing a technocentric worldview by which blueprints based on external policy interventions can solve global environmental dilemmas. Each issue also has a contrasting populist discourse that portrays local actors as victims of external interventions bringing about degradation and exploitation. The managerial discourses dominate in all four issues, but important inputs are also supplied to political decisions from populist discourses. There are, in addition, heterodox ideas and denial claims in each of these areas, to a greater or lesser extent, in which the existence or severity of the environmental problem are questioned. We present evidence from location-specific research which does not fit easily with the dominant managerialist nor with the populist discourses. The research shows that policy-making institutions are distanced from the resource users and that local scale environmental management moves with a distinct dynamic and experiences alternative manifestations of environmental change and livelihood imperatives. [source]

Development Discourses and Peasant,Forest Relations: Natural Resource Utilization as Social Process

Integrating species life-history traits and patterns of deforestation in amphibian conservation planning

DIVERSITY AND DISTRIBUTIONS, Issue 1 2010
C. G. Becker
Abstract Aim, To identify priority areas for amphibian conservation in southeastern Brazil, by integrating species life-history traits and patterns of deforestation. Location, State of São Paulo, Brazil. Methods, We used the software Marxan to evaluate different scenarios of amphibian conservation planning. Our approach differs from previous methods by explicitly including two different landscape metrics; habitat split for species with aquatic larvae, and habitat loss for species with terrestrial development. We evaluated the effect of habitat requirements by classifying species breeding habitats in five categories (flowing water, still water permanent, still water temporary, bromeliad or bamboo, and terrestrial). We performed analyses using two scales, grid cells and watersheds and also considered nature preserves as protected areas. Results, We found contrasting patterns of deforestation between coastal and inland regions. Seventy-six grid cells and 14 watersheds are capable of representing each species at least once. When accounting for grid cells already protected in state and national parks and considering species habitat requirements we found 16 high-priority grid cells for species with one or two reproductive habitats, and only one cell representing species with four habitat requirements. Key areas for the conservation of species breeding in flowing and permanent still waters are concentrated in southern state, while those for amphibians breeding in temporary ponds are concentrated in central to eastern zones. Eastern highland zones are key areas for preserving species breeding terrestrially by direct or indirect development. Species breeding in bromeliads and bamboos are already well represented in protected areas. Main conclusions, Our results emphasize the need to integrate information on landscape configuration and species life-history traits to produce more ecologically relevant conservation strategies. [source]

Investigation of coupling between surface processes and induced flow in the lower continental crust as a cause of intraplate seismicity

EARTH SURFACE PROCESSES AND LANDFORMS, Issue 12 2006
Rob Westaway
Abstract Many studies have highlighted the role of coupling between surface processes and flow in the lower continental crust in deforming the crust and creating topographic relief over Quaternary timescales. On the basis of the rheological knowledge gained, it is suggested that intraplate seismicity can also be caused by coupling between surface processes and flow in the lower continental crust. This view is shown to be a natural consequence of the modern idea that isostatic equilibrium is maintained by flow in the weak lower crust in response to erosion and sedimentation. It is supported by a general correlation between the vigour of surface processes and rates of intraplate seismicity, and by instances of seasonal seismicity that correlates with seasonal climate. Human interference in the environment can affect surface loading: for instance, deforestation for agriculture or urban development can cause increased erosion rates; global warming is expected to cause increased storminess (and thus increased erosion rates) and/or global sea-level rise. The possibility of increased rates of seismicity resulting from these processes should thus be considered in future hazard assessment. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Extinction debt on oceanic islands

ECOGRAPHY, Issue 2 2010
Kostas A. Triantis
Habitat destruction is the leading cause of species extinctions. However, there is typically a time-lag between the reduction in habitat area and the eventual disappearance of the remnant populations. These "surviving but ultimately doomed" species represent an extinction debt. Calculating the magnitude of such future extinction events has been hampered by potentially inaccurate assumptions about the slope of species,area relationships, which are habitat- and taxon-specific. We overcome this challenge by applying a method that uses the historical sequence of deforestation in the Azorean Islands, to calculate realistic and ecologically-adjusted species,area relationships. The results reveal dramatic and hitherto unrecognized levels of extinction debt, as a result of the extensive destruction of the native forest:>95%, in<600,yr. Our estimations suggest that more than half of the extant forest arthropod species, which have evolved in and are dependent on the native forest, might eventually be driven to extinction. Data on species abundances from Graciosa Island, where only a very small patch of secondary native vegetation still exists, as well as the number of species that have not been found in the last 45,yr, despite the extensive sampling effort, offer support to the predictions made. We argue that immediate action to restore and expand native forest habitat is required to avert the loss of numerous endemic species in the near future. [source]

The Paradoxes of Environmental Policy and Resource Management in Reform-Era China,

ECONOMIC GEOGRAPHY, Issue 3 2000
Joshua Muldavin
Abstract: Over the last 5,000 years serious environmental problems,deforestation, desertification, erosion, and widespread pollution of air, land, and water,have prevailed throughout most of China, brought about by a diverse set of social and political contexts. In this paper I focus on an enduring contradiction associated with the post-1978 reforms, namely accelerated environmental resource degradation in rural areas amid unprecedented national economic growth. Declining entitlements to assets and social capital in China's rural village populations are a crucial aspect of altered state-peasant relations, as these are increasingly mediated by the market during China's transition to a hybrid economy. This has resulted in changing patterns of resource use, impacting both the environment and peasant livelihoods. A brief assessment of China's postrevolutionary environmental policy and management practices provides the context for detailed case studies in Henan Province. These examples highlight the relationship between political-economic changes and environmental policy and management. Contrary to reform rhetoric, rural peasants' embracing of reform policies does not necessarily optimize their welfare or promote sustainable use of resources. The case studies reveal alternative pathways for villages, ones that ought to be brought into the policy debate spotlight. [source]

A comparison of fish assemblages associated with different riparian vegetation types in the Hawkesbury,Nepean River system

FISHERIES MANAGEMENT & ECOLOGY, Issue 4 2003
I. Growns
Abstract Fish assemblages in six reaches of the Hawkesbury,Nepean River were studied to identify the effects of two types of riparian vegetation; well-vegetated banks supporting complex flora dominated by trees and shrubs, and grassed banks, that have been colonised only by grasses after historical deforestation. The fish assemblages showed both spatial and temporal differences and habitats adjacent to grassed banks supported more individuals and more fish species than well-vegetated banks. Three small species of fish, firetail gudgeon, Hypseleotris galii (Ogilby), flathead gudgeon, Philypnodon grandiceps (Krefft), and empire gudgeon, Hypseleotris compressa (Krefft), occurred in greater abundances adjacent to grassed banks, but freshwater mullet, Myxus petardi (Castelnau), were less abundant near grassed banks than beside well-vegetated banks. Differences were also shown in the size frequencies of the four larger fish species between riparian vegetation types. The observed differences in the distributions of fish species appeared to be related to the greater abundance aquatic macrophytes near grassed banks, probably an effect of shading of macrophytes near well-vegetated banks. [source]

River restoration, habitat heterogeneity and biodiversity: a failure of theory or practice?

FRESHWATER BIOLOGY, Issue 2010
MARGARET A. PALMER
Summary 1. Stream ecosystems are increasingly impacted by multiple stressors that lead to a loss of sensitive species and an overall reduction in diversity. A dominant paradigm in ecological restoration is that increasing habitat heterogeneity (HH) promotes restoration of biodiversity. This paradigm is reflected in stream restoration projects through the common practice of re-configuring channels to add meanders and adding physical structures such as boulders and artificial riffles to restore biodiversity by enhancing structural heterogeneity. 2. To evaluate the validity of this paradigm, we completed an extensive evaluation of published studies that have quantitatively examined the reach-scale response of invertebrate species richness to restoration actions that increased channel complexity/HH. We also evaluated studies that used manipulative or correlative approaches to test for a relationship between physical heterogeneity and invertebrate diversity in streams that were not in need of restoration. 3. We found habitat and macroinvertebrate data for 78 independent stream or river restoration projects described by 18 different author groups in which invertebrate taxa richness data in response to the restoration treatment were available. Most projects were successful in enhancing physical HH; however, only two showed statistically significant increases in biodiversity rendering them more similar to reference reaches or sites. 4. Studies manipulating structural complexity in otherwise healthy streams were generally small in scale and less than half showed a significant positive relationship with invertebrate diversity. Only one-third of the studies that attempted to correlate biodiversity to existing levels of in-stream heterogeneity found a positive relationship. 5. Across all the studies we evaluated, there is no evidence that HH was the primary factor controlling stream invertebrate diversity, particularly in a restoration context. The findings indicate that physical heterogeneity should not be the driving force in selecting restoration approaches for most degraded waterways. Evidence suggests that much more must be done to restore streams impacted by multiple stressors than simply re-configuring channels and enhancing structural complexity with meanders, boulders, wood, or other structures. 6. Thematic implications: as integrators of all activities on the land, streams are sensitive to a host of stressors including impacts from urbanisation, agriculture, deforestation, invasive species, flow regulation, water extractions and mining. The impacts of these individually or in combination typically lead to a decrease in biodiversity because of reduced water quality, biologically unsuitable flow regimes, dispersal barriers, altered inputs of organic matter or sunlight, degraded habitat, etc. Despite the complexity of these stressors, a large number of stream restoration projects focus primarily on physical channel characteristics. We show that this is not a wise investment if ecological recovery is the goal. Managers should critically diagnose the stressors impacting an impaired stream and invest resources first in repairing those problems most likely to limit restoration. [source]

INTEGRATED LANDSCAPE ANALYSES OF CHANGE OF MIOMBO WOODLAND IN TANZANIA AND ITS IMPLICATION FOR ENVIRONMENT AND HUMAN LIVELIHOOD

GEOGRAFISKA ANNALER SERIES A: PHYSICAL GEOGRAPHY, Issue 1 2009
LENNART STRÖMQUIST
ABSTRACT. Landscapes bear witness to past and present natural and societal processes influencing the environment and human livelihoods. By analysing landscape change at different spatial scales over time the effects on the environment and human livelihoods of various external and internal driving forces of change can be studied. This paper presents such an analysis of miombo woodland surrounding the Mkata plains in central Tanzania. The rich natural landscape diversity of the study area in combination with its historical and political development makes it an ideal observation ground for this kind of study. The paper focuses on long-term physical and biological changes, mainly based on satellite information but also on field studies and a review of documents and literature. The miombo woodlands are highly dynamic semi-arid ecosystems found on a number of nutrient-poor soil groups. Most of the woodlands are related to an old, low-relief geomorphology of erosion surfaces with relatively deep and leached soils, or to a lesser extent also on escarpments and steep Inselberg slopes with poor soils. Each period in the past has cast its footprints on the landscape development and its potential for a sustainable future use. On a regional level there has been a continual decrease in forest area over time. Expansion of agriculture around planned villages, implemented during the 1970s, in some cases equals the loss of forest area (Mikumi-Ulaya), whilst in other areas (Kitulangalo), the pre-independence loss of woodland was small; the agricultural area was almost the same during the period 1975,1999, despite the fact that forests have been lost at an almost constant rate over the same period. Illegal logging and charcoal production are likely causes because of the proximity to the main highway running through the area. Contrasting to the general regional pattern are the conditions in a traditional village (Ihombwe), with low immigration of people and a maintained knowledge of the resource potential of the forest with regards to edible plants and animals. In this area the local community has control of the forest resources in a Forest Reserve, within which the woody vegetation has increased in spite of an expansion of agriculture on other types of village land. The mapping procedure has shown that factors such as access to transport and lack of local control have caused greater deforestation of certain areas than during the colonial period. Planned villages have furthermore continued to expand over forest areas well after their implementation, rapidly increasing the landscape fragmentation. One possible way to maintain landscape and biodiversity values is by the sustainable use of traditional resources, based on local knowledge of their management as illustrated by the little change observed in the traditionally used area. [source]

History of Deforestation and Reforestation in the Dinaric Karst

Local Knowledge and Economic Realities Affecting Soil Erosion in the Rach Rat Catchment, Vietnam

GEOGRAPHICAL RESEARCH, Issue 1 2008
DAO KIM NGUYEN THUY BINH
Abstract Several parts of Binh Phuóc Province, southern Vietnam, suffer from degraded soils and vegetation as a result of both natural erosion of weak mud rocks and sandstones and intensive human activity, especially through land clearing for agriculture on unstable slopes, deforestation, and abandonment of poor farmland. The underlying cause of this land degradation has been the farming habits of migrants of varying ethnic groups who have settled in the area since 1980. The indigenous farming knowledge of these people and the role of that knowledge in soil erosion were examined by a series of household surveys. They enabled farming practices to be related to ground cover established from a 2002 Landsat 7 ETM (Enhanced Thematic Mapper), and erosion data from a series of erosion bridge measurements. A GIS (Geographical Information System) approach was piloted as a means of identifying areas vulnerable to erosion. This could then be combined with the understanding of farming practices to reveal the relative roles of farmer behaviour, crop cover, and slope and soil characteristics in the erosion process. Land use, local people's knowledge and economic realities are the main factors, as well as natural conditions, that drive this land degradation. [source]

Life at Lofty Heights

GERMAN RESEARCH, Issue 1 2006
Christian H. Schulze Dr.
Studies of moths in Borneo provide new clues to understanding the diversity of tropical species and in assessing the consequences of deforestation [source]

Soil organic carbon stock change due to land use activity along the agricultural frontier of the southwestern Amazon, Brazil, between 1970 and 2002

GLOBAL CHANGE BIOLOGY, Issue 10 2010
STOÉCIO M. F. MAIA
Abstract The southwestern portion of the Brazilian Amazon arguably represents the largest agricultural frontier in the world, and within this region the states of Rondônia and Mato Grosso have about 24% and 32% of their respective areas under agricultural management, which is almost half of the total area deforested in the Brazilian Amazon biome. Consequently, it is assumed that deforestation in this region has caused substantial loss of soil organic carbon (SOC). In this study, the changes in SOC stocks due to the land use change and management in the southwestern Amazon were estimated for two time periods from 1970,1985 and 1985,2002. An uncertainty analysis was also conducted using a Monte Carlo approach. The results showed that mineral soils converted to agricultural management lost a total of 5.37 and 3.74 Tg C yr,1 between 1970,1985 and 1985,2002, respectively, along the Brazilian Agricultural Frontier in the states of Mato Grosso and Rondônia. Uncertainties in these estimates were ±37.3% and ±38.6% during the first and second time periods, respectively. The largest sources of uncertainty were associated with reference carbon (C) stocks, expert knowledge surveys about grassland condition, and the management factors for nominal and degraded grasslands. These results showed that land use change and management created a net loss of C from soils, however, the change in SOC stocks decreased substantially from the first to the second time period due to the increase in land under no-tillage. [source]

Global evidence that deforestation amplifies flood risk and severity in the developing world

GLOBAL CHANGE BIOLOGY, Issue 11 2007
COREY J. A. BRADSHAW
Abstract With the wide acceptance of forest-protection policies in the developing world comes a requirement for clear demonstrations of how deforestation may erode human well-being and economies. For centuries, it has been believed that forests provide protection against flooding. However, such claims have given rise to a heated polemic, and broad-scale quantitative evidence of the possible role of forests in flood protection has not been forthcoming. Using data collected from 1990 to 2000 from 56 developing countries, we show using generalized linear and mixed-effects models contrasted with information-theoretic measures of parsimony that flood frequency is negatively correlated with the amount of remaining natural forest and positively correlated with natural forest area loss (after controlling for rainfall, slope and degraded landscape area). The most parsimonious models accounted for over 65% of the variation in flood frequency, of which nearly 14% was due to forest cover variables alone. During the decade investigated, nearly 100 000 people were killed and 320 million people were displaced by floods, with total reported economic damages exceeding US$1151 billion. Extracted measures of flood severity (flood duration, people killed and displaced, and total damage) showed some weaker, albeit detectable correlations to natural forest cover and loss. Based on an arbitrary decrease in natural forest area of 10%, the model-averaged prediction of flood frequency increased between 4% and 28% among the countries modeled. Using the same hypothetical decline in natural forest area resulted in a 4,8% increase in total flood duration. These correlations suggest that global-scale patterns in mean forest trends across countries are meaningful with respect to flood dynamics. Unabated loss of forests may increase or exacerbate the number of flood-related disasters, negatively impact millions of poor people, and inflict trillions of dollars in damage in disadvantaged economies over the coming decades. This first global-scale empirical demonstration that forests are correlated with flood risk and severity in developing countries reinforces the imperative for large-scale forest protection to protect human welfare, and suggests that reforestation may help to reduce the frequency and severity of flood-related catastrophes. [source]