Direct seeding of dry forest tree species in abandoned pastures: effects of grass canopy and seed burial on germination.

Natural tree regeneration in abandoned pastures can be hampered by various biotic and abiotic filters, including seed removal and predation. We tested the effects of maintenance and removal of grass and seed deposition (buried and unburied) on seed germination of 12 tree species in dry forest pastures. We obtained evidence supporting the hypothesis that seeds attain higher germination under a grass canopy than on bare ground. For most species, grass cover provides safety from seed predators and facilitates germination by providing a suitable microclimate with soil humidity similar to the forest. The hypothesis that buried seeds attain higher germination was not supported by our data. Predation and removal of unburied seeds ranged from 0 to 77 % and, alone or together, were the major causes of nongermination. Direct seeding is a promising technique for revegetation of recently abandoned pastures in areas originally covered by tropical dry forests. The high germination rate of seeds deposited on the ground and under grass reduces costs during initial restoration stages, potentially facilitating the spread and use of this technique

Tree seedling survival and growth in logged and undisturbed seasonal deciduous forest fragments in central Brazil.

We evaluated the survival and growth of Amburana cearensis, Cedrela fissilis, and Sterculia striata seedlings in three seasonally tropical dry forest fragments that were subjected to different logging levels (intact, intermediately and heavily logged). In each fragment, we planted 40 seedlings of each species and monitored these over a period of 1 year. The highest seedling survival rate (64%) occurred in the heavily logged fragment, which, however, also had the highest mortality risk for all species during the dry season. Only S. striata seedlings had different survival rates among the fragments. Height and diameter growth were higher at sites with higher canopy openness in the wet season. The survival and growth rates of seedlings planted in logged fragments indicate that this technique can be applied to restore and enrich logged forests of the Paranã River Basin

Enriquecimento de sistemas silvopastoris com mudas de espécies nativas do Cerrado.

Suplemento. Edição dos Anais do 10 Congresso Brasileiro de Agroecologia; 6 Congresso Latino-americano de Agroecologia; 5 Seminário de Agroecologia do Distrito Federal e Entorno, Brasília, DF, set. 2017 Na publicação: Aldicir Scariot

Uso e práticas de manejo de faveira (Dimorphandra gardneriana Tul.) na região da Chapada do Araripe, Ceará: implicações ecológicas e sócio-econômicas.

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Fragmentação da paisagem no entorno e na Reserva de Desenvolvimento Sustentável Nascentes das Geraizeiras, Minas Gerais.

The expansion of pastures and cropping fields was responsible for most deforestation in Northern Minas Gerais state. In this study, we assessed the dynamics of land use and cover that occurred in recent decades (1986 to 2015) in the Sustainable Development Reserve Nascentes das Geraizeiras (SDR-NG) and a 10 km buffer zone in the state of Minas Gerais. The effects of deforestation on native vegetation fragmentation were also evaluated using remotely sensed data and landscape analysis. This study indicates that deforestation affected more than half of the native vegetation by 2015, which affected the integrity of native vegetation fragments in the entire study area. The SDR-NG contributed to mitigating the fragmentation of natural vegetation that occurred around that Reserve because of a secondary regrowth observed in some previously degraded areas. It was observed that the most significant environmental threat to that Reserve is fire events, which vary annually in extent and socio-environmental damages. The land sustained use in the SDR-NG could be improved by expanding sustainable economic activities, such as using non-timber forest products, the implementation of agroforestry systems, and other economic activities moderately. These practices will ensure the maintenance of natural resources, economic production, increase income and labor opportunities to local communities, and include all social segments and populations living within and around that Reserve.A expansão de áreas de pastagens e cultivos agrícolas foi responsável pela maior parte do desmatamento no norte do estado de Minas Gerais. No presente estudo, avaliou-se a dinâmica do uso e cobertura da terra ocorrida nas últimas décadas (1986 a 2015) na Reserva de Desenvolvimento Sustentável Nascentes das Geraizeiras (RDS-NG) e em uma zona de 10 km do seu entorno no estado de Minas Gerais. Avaliaram-se também os efeitos do desmatamento sobre a fragmentação da vegetação natural usando dados de sensoriamento remoto e análise da paisagem. Os resultados deste estudo indicam que o desmatamento afetou mais da metade da vegetação natural até 2015, agravando a integridade dos fragmentos de vegetação nativa na área de estudo. A RDS-NG contribuiu para mitigar a fragmentação da vegetação natural ocorrida no entorno daquela Reserva com a regeneração natural de algumas áreas degradadas. Observou-se que a maior ameaça ambiental à reserva é a ocorrência do fogo, que varia anualmente em extensão e danos socioambientais. O uso sustentado das terras na RDS-NG pode ser melhorado com a ampliação das práticas de atividades econômicas sustentáveis, como o aproveitamento de produtos florestais não madeireiros, a implantação de consórcios agroflorestais e outras atividades econômicas de forma moderada. Essas práticas contribuirão para garantir a manutenção dos recursos naturais, a produção econômica e a geração de renda e trabalho à comunidade local, com inclusão de todos os segmentos sociais da população da Reserva e seu entorno

Vegetação e flora.

O processo de redução e isolamento da vegetação natural, conhecido como fragmentação de habitat tem consequências sobre a estrutura e os processos das comunidades vegetais, que podem ser naturais ou geralmente causados pela ação antrópica e, apesar das implicações da fragmentação de habitat na manutenção da biodiversidade, muito de seus efeitos de curto, médio e longo prazo ainda não são entendidos. Resultados de estudos em diversos ecossistemas têm demonstrado que a compreensão de somente uma ou de poucas características dos fragmentos, não é suficiente para entender ou prever como a biodiversidade será afetada. É, portanto, essencial a compreensão dos diversos fatores que podem estar simultaneamente ou em sinergismo sobre a vegetação dos fragmentos tais como o tamanho, a forma, a idade, o uso e a matriz, entre outros

Effects of Brazil's political crisis on the science needed for biodiversity conservation.

The effects of Brazil's political crisis on science funding necessary for biodiversity conservation are likely to be global. Brazil is not only the world?s most biodiverse nation, it is responsible for the greater part of the Amazon forest, which regulates the climate and provides rain to much of southern South America. Brazil was a world leader in satellite monitoring of land-use change, in-situ biodiversity monitoring, reduction in tropical-forest deforestation, protection of indigenous lands, and a model for other developing nations. Coordinated public responses will be necessary to prevent special-interest groups from using the political crisis to weaken science funding, environmental legislation and law enforcement

An Amazonian rainforest and its fragments as a laboratory of global change

We synthesize findings from one of the world’s largest and longest-running experimental investigations, the Biological Dynamics of Forest Fragments Project (BDFFP). Spanning an area of ~1,000 km2 in central Amazonia, the BDFFP was initially designed to evaluate the effects of fragment area on rainforest biodiversity and ecological processes. However, over its 38-year history to date the project has far transcended its original mission, and now focuses more broadly on landscape dynamics, forest regeneration, regional- and global-change phenomena, and their potential interactions and implications for Amazonian forest conservation. The project has yielded a wealth of insights into the ecological and environmental changes in fragmented forests. For instance, many rainforest species are naturally rare and hence are either missing entirely from many fragments or so sparsely represented as to have little chance of long-term survival. Additionally, edge effects are a prominent driver of fragment dynamics, strongly affecting forest microclimate, tree mortality, carbon storage and a diversity of fauna. Even within our controlled study area, the landscape has been highly dynamic: for example, the matrix of vegetation surrounding fragments has changed markedly over time, succeeding from large cattle pastures or forest clearcuts to secondary regrowth forest. This, in turn, has influenced the dynamics of plant and animal communities and their trajectories of change over time. In general, fauna and flora have responded differently to fragmentation: the most locally extinction-prone animal species are those that have both large area requirements and low tolerance of the modified habitats surrounding fragments, whereas the most vulnerable plants are those that respond poorly to edge effects or chronic forest disturbances, and that rely on vulnerable animals for seed dispersal or pollination. Relative to intact forests, most fragments are hyperdynamic, with unstable or fluctuating populations of species in response to a variety of external vicissitudes. Rare weather events such as droughts, windstorms and floods have had strong impacts on fragments and left lasting legacies of change. Both forest fragments and the intact forests in our study area appear to be influenced by larger-scale environmental drivers operating at regional or global scales. These drivers are apparently increasing forest productivity and have led to concerted, widespread increases in forest dynamics and plant growth, shifts in tree-community composition, and increases in liana (woody vine) abundance. Such large-scale drivers are likely to interact synergistically with habitat fragmentation, exacerbating its effects for some species and ecological phenomena. Hence, the impacts of fragmentation on Amazonian biodiversity and ecosystem processes appear to be a consequence not only of local site features but also of broader changes occurring at landscape, regional and even global scales