Succession and management of tropical dry forests in the Americas: Review and new perspectives

Understanding tropical forest succession is critical for the development of tropical forest conservation strategies worldwide, given that tropical secondary forests can be considered the forests of the future. Tropical dry forests (TDF) are among the most threatened tropical ecosystems, there are more secondary forests and forest restoration efforts that require a better understanding of successional processes. The main goal of this synthesis for this special issue on the ecology and management of tropical dry forests in the Americas is to present a summarized review of the current knowledge of the ecology and management implications associated to TDF succession. We explore specific issues associated to tropical dry forest succession with emphasis on the use of chronosequences, plant diversity and composition, plant phenology and remote sensing, pollination, and animal-plant interactions; all under the integrating umbrella of ecosystem succession. We also emphasize the need to conduct socio-ecological research to understand changes in land-use history and its effects on succession and forest regeneration of TDF. We close this paper with some thoughts and ideas associated with the strong need for an integrating dimension not considered until today: the role of cyberinfrastructure and eco-informatics as a tool to support sound conservation, management and understanding of TDF in the Americas. (C) 2009 Elsevier B.V. All rights reserved.

Time-course of photosynthetic induction in four tropical woody species grown in contrasting irradiance habitats

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

Anurans of a seasonally dry tropical forest: Morro do Diabo State Park, São Paulo state, Brazil

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

Spatial and temporal distribution of tadpole assemblages (Amphibia, Anura) in a seasonal dry tropical forest of southeastern Brazil

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

New aerophytic morphospecies of Cyanobacteria from tropical forest fragments in northwestern São Paulo state, Brazil

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

Corticolous green algae from tropical forest remnants in the northwest region of São Paulo State, Brazil

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

Corticolous cyanobacteria from tropical forest remnants in northwestern São Paulo State, Brazil

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

Assessment of tropical forest degradation by selective logging and fire using Landsat imagery

Many studies have assessed the process of forest degradation in the Brazilian Amazon using remote sensing approaches to estimate the extent and impact by selective logging and forest fires on tropical rain forest. However, only a few have estimated the combined impacts of those anthropogenic activities. We conducted a detailed analysis of selective logging and forest fire impacts on natural forests in the southern Brazilian Amazon state of Mato Grosso, one of the key logging centers in the country. To achieve this goal a 13-year series of annual Landsat images (1992-2004) was used to test different remote sensing techniques for measuring the extent of selective logging and forest fires, and to estimate their impact and interaction with other land use types occurring in the study region. Forest canopy regeneration following these disturbances was also assessed. Field measurements and visual observations were conducted to validate remote sensing techniques. Our results indicated that the Modified Soil Adjusted Vegetation Index aerosol free (MSAVI(af)) is a reliable estimator of fractional coverage under both clear sky and under smoky conditions in this study region. During the period of analysis, selective logging was responsible for disturbing the largest proportion (31%) of natural forest in the study area, immediately followed by deforestation (29%). Altogether, forest disturbances by selective logging and forest fires affected approximately 40% of the study site area. Once disturbed by selective logging activities, forests became more susceptible to fire in the study site. However, our results showed that fires may also occur in undisturbed forests. This indicates that there are further factors that may increase forest fire susceptibility in the study area. Those factors need to be better understood. Although selective logging affected the largest amount of natural forest in the study period, 35% and 28% of the observed losses of forest canopy cover were due to forest fire and selective logging combined and to forest fire only, respectively. Moreover, forest areas degraded by selective logging and forest fire is an addition to outright deforestation estimates and has yet to be accounted for by land use and land cover change assessments in tropical regions. Assuming that this observed trend of land use and land cover conversion continues, we predict that there will be no undisturbed forests remaining by 2011 in this study site. Finally, we estimated that 70% of the total forest area disturbed by logging and fire had sufficiently recovered to become undetectable using satellite data in 2004. (C) 2010 Elsevier B.V. All rights reserved.

An integrated approach to identification and conservation of medicinal plants in the tropical forest - A Brazilian experience

An integrated and interdisciplinary research programme with native medicinal plants from tropical forests has been performed in order to obtain new forest products for sustainable use in regional markets vis-à-vis ecosystem conservation. For the success of this programme ethnopharmacological studies are very important with respect to (i) identification of useful plants including medicinal and aromatic species; (ii) recuperation and preservation of traditional knowledge about native plants; and (iii) identification of potential plants with economic value. The plants are selected with a view to evaluate efficacy and safety (pharmacological and toxicological studies), and phytochemical profile and quality control (phytochemical and chromatographic characterization). These studies are very important to add value to plant products and also to mitigate unscrupulous exploitation of medicinal plants by local communities, since multiple use of plants represents an excellent strategy for sustaining the tropical ecosystem through ex situ and in situ conservation. Thus, conservation of tropical resources is possible in conjunction with improvements in the quality of life of the traditional communities and production of new products with therapeutic, cosmetic and 'cosmeceutic' value. © NIAB 2005.

Soil seed banks in tropical forest fragments with different disturbance histories in southeastern Brazil

Soil seed banks are considered an important mechanism for natural regeneration in tropical forest ecosystems. This paper investigated the soil seed bank in two semideciduous seasonal tropical forest fragments with different disturbance histories in Botucatu, southeastern Brazil. In each study site, 40 superficial soil samples (30 cm × 30 cm × 5 cm) were taken at the end of both the dry and rainy seasons. The seeds were estimated by the germination method. Average soil seed density was 588.6 and 800.3 seeds m-2, respectively, for site 1 (less disturbed) and site 2 (more disturbed). Seed density and diversity (H′) were significantly higher in site 2 in both seasons. Non-woody taxa predominated in both fragments, but pioneer tree species were better represented in the less disturbed forest. Both ecosystems have a potential for regeneration from soil seed banks, but this potential is higher in the less disturbed site. Low richness and density of pioneer tree species in the seed bank indicate that the ecosystem has lost its resilience. The seed bank is not as important in these ecosystems as in other forests. Results indicate that management strategies to restore these forests should take into account the possibility of recovering soil seed bank processes and dynamics. © 2007 Elsevier B.V. All rights reserved.

Longitudinal patterns of fish assemblages in mountain streams from tropical forest biome

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Spatio-temporal distribution of calling male frogs in Morro do Diabo State Park (Southeastern Brazil): implications for conservation and management in a seasonally dry tropical forest

The aims of this study are to determine how anuran calling males are spatially and temporally distributed in the Morro do Diabo State Park (MDSP), and to test for indicator species in different breeding habitats. We found high species turnover among breeding habitats of different hydroperiods. Our results indicate that spatial partitioning is more important than seasonal occurrence in permitting species coexistence at MDSP. Indicator Species Analysis identified one species associated with a local stream, one species associated with permanent ponds, two species associated with temporary ponds, and three species associated with a semipermanent pond. Guilds of species do not appear to stratify their distributions throughout the year, since most species occur during the rainy and warm months and are thus temporally overlapping. The main conservation implication of our work is the need to protect the different areas of the park where these unique breeding habitats, and their associated anuran assemblages, are found.

Combining plant and bird data increases the accuracy of an Index of Biotic Integrity to assess conservation levels of tropical forest fragments

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)