中国森林火灾与对策

本文剖析了我国森林火灾与损失概况和我国森林火灾分布及其特点。根据森林燃烧环理论,提出了符合我国国情的综合森林防火对策,即从森林生态系统角度出发,以林火性状为依据,进行火险区划,以工程防火为中心,群众防火为主,营林、生物防火为基础,有条件地用火防火的对策,有效地控制森林火灾,使火灾发生控制在允许范围内,其损失限制在一定经济水平以下,充分发挥火生态的效益,维护生态平衡,保证林区社会安定和林区经济的不断繁荣与发展。     

森林生态系统在碳循环中的作用

描述了森林生态系统的碳循环及其在全球碳循环中的作用，说明了森林生态系统在碳循环中的作用主要取决于森林生态系统的生物量、林产品、植物枯枝落叶和根系碎屑以及森林土壤。最后，阐明了中国森林生态系统碳循环的研究现状和趋势。     

Simulation of NO and N2O emissions from a spruce forest during a freeze/thaw event using an N-flux submodel from the PnET-N-DNDC model integrated to CoupModel

The amount of nitrogen gases (N₂O, NO and N₂) emitted from forest soils depends on interactions between soil properties, climatic factors and soil management. To increase the understanding of nitrogen processes in soil ecosystems, two dynamic models, CoupModel (coupled heat and mass transfer model for soil–plant–atmosphere systems) and the denitrification–decomposition (DNDC) model were selected. Both are dynamic models with different submodels for soil, vegetation, hydrology and climate system. CoupModel has a higher degree of detail on soil physical and abiotic components, whereas the DNDC model contains details of microbiological processes involved in production of nitrogen gases. To improve the previous simple submodel of nitrogen emission in CoupModel, we included a submodel corresponding to the forest version of DNDC containing photosynthesis/evapotranspiration-nitrogen (PnET-N-DNDC model).     

Threshold responses of Amazonian stream fishes to timing and extent of deforestation

Deforestation is a primary driver of biodiversity change through habitat loss and fragmentation. Stream biodiversity may not respond to deforestation in a simple linear relationship. Rather, threshold responses to extent and timing of deforestation may occur. Identification of critical deforestation thresholds is needed for effective conservation and management. We tested for threshold responses of fish species and functional groups to degree of watershed and riparian zone deforestation and time since impact in 75 streams in the western Brazilian Amazon. We used remote sensing to assess deforestation from 1984 to 2011. Fish assemblages were sampled with seines and dip nets in a standardized manner. Fish species (n = 84) were classified into 20 functional groups based on ecomorphological traits associated with habitat use, feeding, and locomotion. Threshold responses were quantified using threshold indicator taxa analysis. Negative threshold responses to deforestation were common and consistently occurred at very low levels of deforestation (<20%) and soon after impact (<10 years). Sensitive species were functionally unique and associated with complex habitats and structures of allochthonous origin found in forested watersheds. Positive threshold responses of species were less common and generally occurred at >70% deforestation and >10 years after impact. Findings were similar at the community level for both taxonomic and functional analyses. Because most negative threshold responses occurred at low levels of deforestation and soon after impact, even minimal change is expected to negatively affect biodiversity. Delayed positive threshold responses to extreme deforestation by a few species do not offset the loss of sensitive taxa and likely contribute to biotic homogenization.     

Effects of crowding due to habitat loss on species assemblage patterns

Terrestrial animals are negatively affected by habitat loss, which is assessed on a landscape scale, whereas secondary effects of habitat loss, such as crowding, are usually disregarded. Such impacts are inherently hard to address and poorly understood, and there is a growing concern that they could have dire consequences. We sampled birds throughout a deforestation process to assess crowding stress in an adjacent habitat remnant in the southern Brazilian Atlantic Forest. Crowding is expected of highly mobile taxa, especially given the microhabitat heterogeneity of Neotropical forests, and we hypothesized that the arrival of new individuals or species in refuges shifts assemblage patterns. We used point counts to obtain bird abundances in a before-after-control-impact design sampling of a deforestation event. Temporal changes in taxonomic and functional diversity were examined with metrics used to assess alpha and beta diversity, turnover of taxonomic and functional similarity, and taxonomic and functional composition. Over time increased abundance of some species altered the Simpson index and affected the abundance-distribution of traits in the habitat remnant. Taxonomic composition and functional composition changed in the remnant, and thus bird assemblages changed over time. Taxonomic and functional metrics indicated that fugitives affected resident assemblages in refuges, and effects endured >2 years after the deforestation processes had ceased. Dissimilarity of taxonomic composition between pre- and postdeforestation assemblages increased, whereas functional composition reverted to preimpact conditions. We found that ecological disruptions resulted from crowding and escalated into disruptions of species’ assemblages and potentially compromising ecosystem functioning. It is important to consider crowding effects of highly mobile taxa during impact assessments, especially in large-scale infrastructure projects that may affect larger areas than is assumed.     

Ten years of contested enforcement of the Forest Law in Salta,Argentina. The role of land-change science and political ecology

ABSTRACT

In this study, we present a critical account of the enforcement of the Forest Law in the Province of Salta, Argentina. We discuss whether the objectives of this law were accomplished and we analyze the role that some technical tools, coupled with specific theoretical approaches, could play in its future enforcement. We illustrate our analysis with data from a case study in the Chaco region of this Province. We identified, mapped and analyzed land claims by indigenous communities and small-scale agricultural producers, and large-scale land acquisitions, and we discuss how these two variables could be used to improve the technical accuracy and the social legitimacy of the zoning map required by the Forest Law. We conclude that a balanced combination of land-change science methods and political ecology can be useful to improve the fairness of decision-making processes and the sustainability of social-environmental governance in agricultural frontiers.     

Produced natures through the lens of biodiversity conservation and tourism: the Ponta Negra Caiçara in the Atlantic Forest Coast of Brazil

Understanding nature as an outcome of organising discourses generated through relative experiences of our surroundings has been the groundwork of a political ecology that deals with the distribution of environmental justice among people with different degrees of power. In this paper, we examine how the environmental legislation and the tourism industry have constructed the term Caiçara as a way to categorise the inhabitants of the Atlantic Forest Coast of Brazil, in ways that meet their goals, but in turn occludes the discourse of the Caiçara themselves. Ethnographic research conducted in Ponta Negra, a small coastal community located at the heart of the Juatinga Ecological Reserve (Paraty, Rio de Janeiro State), as well as a review of key legislation, management plans and tourism materials form the empirical basis of this research. First, we offer a critical examination of the historical origin of the term Caiçara. We then compare contradictory ideas of Caiçara produced by Brazilian environmental legislation and the tourism industry. While the environmental legislation has characterised the Caiçara as fallen angels who are no longer conservation allies, the tourism industry has profited by selling them as ecologically noble savages who still live in harmony with the environment. Our analysis shows how Ponta Negra people have become objects of powerful discourses of nature that hinder the recognition of their collective rights and weaken their position to negotiate for their own desires and aspirations related to their identity and livelihoods.     

保护和恢复阿拉善梭梭生态林的探讨

本文分析了近 40年来阿拉善盟梭梭生态林退化的原因 ,并提出了今后保护与恢复这片梭梭生态林的对策和建议。     

南岳森林土壤的研究——Ⅰ.基本特点和土壤紧实度

本文介绍了南岳的自然条件以及森林土壤的基本特点如酸碱度、土壤含水量、比重、浸水容重、质地、有机质、有效氮、速效磷、速效钾等情况。作者首次应用定量方法即回归分析研究了土壤紧实度与土壤层次、结构及其有机质含量的关系,还讨论了土壤侵蚀和人畜践踏对土壤紧实度的影响。