Geoffrey Blate

World Wildlife Fund · Landscape Conservation and Climate Change

Publications

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    ABSTRACT: Soil characteristics are important drivers of variation in wet tropical forest structure and diversity, but few studies have evaluated these relationships in drier forest types. Using tree and soil data from 48 and 32 1 ha plots, respectively, in a Bolivian moist and dry forest, we asked how soil conditions affect forest structure and diversity within each of the two forest types. After correcting for spatial effects, soil-vegetation relationships differed between the dry and the moist forest, being strongest in the dry forest. Furthermore, we hypothesized that soil nutrients would play a more important role in the moist forest than in the dry forest because vegetation in the moist forest is less constrained by water availability and thus can show its full potential response to soil fertility. However, contrary to our expectations, we found that soil fertility explained a larger number of forest variables in the dry forest (50 percent) than in the moist forest (17 percent). Shannon diversity declined with soil fertility at both sites, probably because the most dominant, shade-tolerant species strongly increased in abundance as soil fertility increased.
    Biotropica 01/2012; 44(3):276-283. · 2.35 Impact Factor
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    ABSTRACT: This study explores potential adaptation approaches in planning and management that the United States Forest Service might adopt to help achieve its goals and objectives in the face of climate change. Availability of information, vulnerability of ecological and socio-economic systems, and uncertainties associated with climate change, as well as the interacting non-climatic changes, influence selection of the adaptation approach. Resource assessments are opportunities to develop strategic information that could be used to identify and link adaptation strategies across planning levels. Within a National Forest, planning must incorporate the opportunity to identify vulnerabilities to climate change as well as incorporate approaches that allow management adjustments as the effects of climate change become apparent. The nature of environmental variability, the inevitability of novelty and surprise, and the range of management objectives and situations across the National Forest System implies that no single approach will fit all situations. A toolbox of management options would include practices focused on forestalling climate change effects by building resistance and resilience into current ecosystems, and on managing for change by enabling plants, animals, and ecosystems to adapt to climate change. Better and more widespread implementation of already known practices that reduce the impact of existing stressors represents an important "no regrets" strategy. These management opportunities will require agency consideration of its adaptive capacity, and ways to overcome potential barriers to these adaptation options.
    Environmental Management 08/2009; 44(6):1022-32. · 1.65 Impact Factor
  • Unasylva: revista internacional de silvicultura e industrias forestales, ISSN 0251-1584, Nº. 231-232, 2009 (Ejemplar dedicado a: Adaptación al cambio climático), pags. 57-62. 01/2009;
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    ABSTRACT: Silvicultural treatments are generally performed to improve yields of commercially valuable tree species by increasing their recruitment and growth rates. In this study we analyze the effects of three different sets of silvicultural treatments on the densities and growth rates of seedlings, saplings and poles of 23 commercial tree species in a moist tropical forest in Bolivia. The treatments vary in intensity of logging and silviculture application, and are compared to a control treatment. Silvicultural treatments applied were liberation of future crop trees from lianas and neighboring competing trees, soil scarification and stand refinements. Treatments were applied to twelve 27-ha plots. In each plot 4 transects were established to assess the density and growth of the regeneration of the 23 commercial species. Effects were measured 1 and 4 years after treatment application and were described using three ecological guilds; shade-tolerant species, partially shade-tolerant species, and long-lived pioneers. We found that the intensive silviculture treatment had the largest impact on the density and growth rates of the regeneration of the commercial species. Overall, the density of regeneration of the commercial species was higher in the control treatment than in the logged treatments 1 year after treatment application, but 3 years later these differences had disappeared. Nevertheless, there were marked shifts in densities when different size classes were considered. In nearly all treatments, the number seedlings decreased over time, while the number of saplings and poles increased. Overall shade-tolerant species were more abundant than the other two ecological guilds. Treatment had a positive effect on density only for long-lived pioneers. Growth of commercial tree regeneration was strongly affected by treatment and was highest in the intensive silvicultural treatment plots where growth of long-lived pioneers was twice that of shade-tolerant species and partial shade-tolerant species. Apart from silvicultural treatments and ecological guild, light availability had the strongest effect on growth rates. These results show that different silvicultural treatments have different effects on the regeneration of commercial tree species and that ecological guilds-specific treatments should be considered in management plans for sustainable timber production in tropical lowland forests.
    Forest Ecology and Management. 03/2008;
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    ABSTRACT: Selective logging is an extensive land-use practice in South America. Governments in the region have enacted policies to promote the establishment and maintenance of economically productive and sustainable forest industries. However, both biological and policy constraints threaten to limit the viability of the industry over the long term. Biological constraints, such as slow tree growth rates, can be overcome somewhat by management practices. In order to improve the likelihood of success for sustainable management, it is important to accept that forests change over time and that managed forests may be different than those of the present. Furthermore, education campaigns must convince decision makers and the public of the value of forest resources. We recommend that the forest sector be governed by simple, understandable regulations, based on sound science and consistent enforcement, and that governments work with, instead of against, industry. Problems of tropical forest management are far from being solved, so biological and social scientists should continue to generate new knowledge to promote effective management
    Frontiers in Ecology and the Environment 5 (2007) 4. 01/2007;
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    ABSTRACT: Reduced impact logging (RIL) systems are currently being promoted in Brazil and other tropical countries in response to domestic and international concern over the ecological and economic sustainability of harvesting natural tropical forests. RIL systems are necessary, but not sufficient, for sustainable forest management because they reduce damage to the forest ecosystem during the initial forest entry. If conditions were identified where RIL costs were clearly less than conventional logging (CL) costs, then a strong incentive for RIL adoption would exist.In this paper, a comparison of costs and revenues was made for typical RIL and CL operations in the eastern Amazon. An economic engineering approach was used to estimate standardized productivity and cost parameters. Detailed data on productivity, harvest volume, wasted wood and damage to the residual stand were collected from operational scale harvest blocks. Productivity and cost data were also collected using surveys of forest products firms.The major conclusion of the study was that RIL was less costly, and more profitable, than CL under the conditions observed at the eastern Amazon study site. Full cost accounting methods were introduced to capture the direct and indirect costs associated with wasted wood. The impact of wasted wood on effective stumpage price provided the largest gain to RIL. Large gains attributable to RIL technology were also observed in skidding and log deck productivity. In addition, investment in RIL yielded an “environmental dividend” in terms of reduced damage to trees in the residual stand and reduction of the amount of ground area disturbed by heavy machinery. Developing institutions that can monetize the value of the environmental dividend remains a major challenge in the promotion of sustainable forest management in the tropics.
    Forest Ecology and Management 06/2002; 163:93-110. · 2.77 Impact Factor
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    ABSTRACT: We set ecosystem conservation priorities based on a comparison of observed levels of threat and protection versus expected levels derived from the use of null models. We used differences in the proportion of threatened and nonthreatened bird species among ecosystems to assess levels of threat and differences in the coverage of parks and protected areas relative to land area to assess levels of protection. We applied this approach to terrestrial biomes of continental South America and determined where recommendations for species and ecosystem conservation converge and diverge. We calculated the percentage of range in each biome for 132 bird species threatened by habitat destruction and 288 nonthreatened bird species. Three biomes (evergreen forest, broadleaf forest, and cold desert) were not included because few bird ranges fell primarily within them. Tropical humid forest and mountain biomes supported the greatest levels of avian species diversity. But only subtropical and temperate rainforests and tropical dry forests supported a higher proportion of threatened bird species than expected, making them ecosystem destruction hotspots. Tropical humid forests and tropical and temperate grasslands supported lesser proportions of threatened bird species than expected (i.e., coldspots), whereas mountain and warm deserts supported similar proportions of threatened and nonthreatened bird species (i.e., neutral). These patterns were corroborated by the apportionment of human population densities among biomes. Highest densities (> 25 per km2) occurred in subtropical and temperate rainforests and tropical dry forests, whereas tropical humid forests and warm deserts supported the lowest human densities (< 1 per km2). The largest proportions of protected areas were in tropical humid forest and mountain biomes, which is in accord with the distribution of avian diversity but not with our assessment of habitat destruction. Protected areas were especially underrepresented in tropical dry forests, making them the most threatened biome.Presentamos una aproximación al problema del establecimiento de prioridades en la conservación de ecosistemas basada en una comparación entre los niveles de amenaza observados y los niveles esperados derivados del uso de modelos nulos. Usamos las diferencias entre ecosistemas en las proporciones de especies de aves amenazadas y no amenazadas para valorar los niveles de amenaza, y las diferencias en el porcentaje de la superficie de cada ecosistema incluido en áreas protegidas como estimador del nivel de protección. Aplicamos esta aproximación al conjunto de los biomus de Sudamérica continental, y estudiamos en que casos las recomendaciones de conservación basadas en especies o ecosistemas son coincidentes o discrepantes. Determinamos el porcentaje del área de distribución incluido en cada bioma para 132 especies de aves amenazadas por destrucción del hábitat y para 288 especies no amenazadas. Tres biomas (bosque templado de hoja perenne, bosque templado de hoja caduca, y desiertos frios) no fueron considerados, pues un número muy bajo de las especies estudiadas tenía su área de distribución incluida primariamente en estos ecosistemas, debido a la escala amplia del análisis; su rareza intrínseca les convierte en prioridades importantes. El bosque tropical húmedo y los biomas de montaña presentaron los mayores niveles de diversidad de especies. Sólo los bosques subtropicales, los bosques lluviosos templados, y los bosques tropicales secos acogieron un porcentaje de especies amenazadas mayor del esperado, lo que les convierte en elementos clave en la conservación de ecosistemas. Los bosques húmedos tropicales y las praderas templadas y tropicales acogieron porcentajes de especies amenazadas menores de los esperado (áreas no prioritarias), mientras que los desiertos de montaña y los cálidos presentaron similares porcentajes de especies amenazadas y no amenazadas (áreas neutras). Estos patrones fueron corroborados por las distribuciones de densidades de población humana en cada bioma. Las mayores densidades (>25 habitantes por km2) se dan en bosques subtropicales, bosques lluviosos templados, y bosques secos tropicales, mientras que los bosques húmedos tropicales y los desiertos cálidos mantienen las densidades más bajas (< 1 por km2). Las mayores proporciones de áreas protegidas correspondieron a los bosque húmedos tropicales y a los biomas de montaña, lo que concuerda con la distribución de diversidades de aves, pero no con nuestra valoración del nivel de destrucción de hábitat. Las áreas protegidas estan especialmente infrarepresentadas en los bosques tropicales secos, que son por tanto el bioma más amenazado.
    Conservation Biology 01/2002; 10(5):1343 - 1352. · 4.36 Impact Factor
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    ABSTRACT: C limate change is already affect-ing forests and other ecosystems, and additional, potentially more severe impacts are expected (IPCC, 2007; CCSP, 2008a, 2008b). As a result, forest managers are seeking practical guidance on how to adapt their current practices and, if necessary, their goals. Adaptations of forest ecosystems, which in this context refer to adjustments in management (as opposed to "natural" adaptation), ideally would reduce the negative impacts of climate change and help managers take advantage of any positive impacts.

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