Soil hydraulic response to land-use change associated with the recent soybean expansion at the Amazon agricultural frontier

Clearing for large-scale soy production and the displacement of cattle-breeding by soybeans are major features of land-use change in the lowland Amazon that can alter hydrologic properties of soils and the runoff generation over large areas. We measured infiltrability and saturated hydraulic conductivity (Ksat) under natural forest, pasture, and soybeans on Oxisols in a region of rapid soybean expansion in Mato Grosso, Brazil. The forest-pasture conversion reduced infiltrability from 1258 to 100 mm/h and Ksat at all depths. The pasture-soy conversion increased infiltrability from 100 to 469 mm/h (attributed to shallow disking), did not affect Ksat at 12.5 cm, but decreased Ksat at 30 cm from 122 to 80 mm/h, suggesting that soybean cultivation enhances subsoil compaction. Permeability decreased markedly with depth under forest, did not change under pasture, and averaged out at one fourth the forest value under soybeans with a similar pattern of anisotropy. Comparisons of permeability with rainfall intensities indicated that land-use change did not alter the predominantly vertical water movement within the soil. We conclude that this landscape is well buffered against land-use changes regarding near-surface hydrology, even though short-lived ponding and perched water tables may occur locally during high-intensity rainfall on pastures and under soybeans.     

Closing the Incentive Gap: The Role of Public and Private Actors in Governing Indonesia's Tuna Fisheries

Indonesia is one of the world's largest tuna producing countries, yet regulatory oversight remains weak and management is poor. Incentive-based approaches are a way to improve state-based resource management, but they often require strong government regulation. In this paper, we use principal–agent theory and the notion of the ‘incentive gap’ to explore how incentives could be brought to bear in Indonesia through a combination of private and public actors. With a shared fish stock like tuna, we argue that a double principal–agent problem emerges, where information, asymmetries between various players complicate management. We focus on the problems of adverse selection and moral hazard in three different tuna fisheries in Indonesia to identify the nature of the incentive gap, and comment on the mix of public and private actors currently engaged in tuna fishery governance towards reducing the gap. The double principal–agent problem is a useful yet underutilized framework to understand the dynamics of shared stocks management. In this first application to a developing country fishery, we conclude that information asymmetries cannot be overcome without the involvement of private actors, who are increasingly becoming important in aligning regional and global objectives with those of fishers themselves.     

Forest Dynamics in the Eastern Ghats of Tamil Nadu,India

The primary deciduous forests in the Eastern Ghats (EG) of Tamil Nadu (TN) India have undergone many changes owing to various need-based forest managements, such as timber extraction for industry, railway sleepers, charcoal, and forest clearance for hydroelectric projects and agriculture, during preindependence and postindependence periods (i.e., from 1800 to 1980). The enactment of a forest conservation act during the 1980s changed the perception of forest managers from utilization to conservation. This study was taken up to assess the forests dynamics in the EG of TN spatially between 1990 and 2003 and nonspatially between 1900 and the 1980s. Landsat Thematic Mapper (TM) and Indian Remote Sensing satellite (IRS) 1D Linear Imaging and Self Scanning (LISS III) data were used to assess forests during 1990 and 2003, respectively. Field floristic survey and secondary data (such as published literature, floras, books, and forest working plans) were used to assess the forest dynamics in terms of forest type and species composition among the preindependence period, the postindependence period, and the present (i.e., before and after 1980). The satellite data analysis revealed a considerable amount of changes in all forest types during the 13 years. The comparison of species composition and forest types between the past and present revealed that need-based forest management along with anthropogenic activity have altered the primary deciduous forest in to secondary and postextraction secondary forests such as southern thorn and southern thorn scrub forests in the middle [400–900 m above mean sea level (MSL)] and lower slopes (<400 m MSL). However, the evergreen forests present at the upper slope (>900 m MSL) and plateau seemed not to be much affected by the forest management. The changes estimated by the satellite data processing in the major forest types such as evergreen, deciduous, southern thorn, and southern thorn scrub are really alarming because these changes have occurred after the implementation of a forest conservation act. The dependence of local people on forests for various purposes in this region is also considerably high, which might be a key factor for the changes in the forests. The results of this study not only provide an outlook on the present status of the forests and the change trends but also provide the basis for further studies on forests in the EG of TN.     

Assessing self-organization of plant communities—A thermodynamic approach

Thermodynamics is a powerful tool for the study of system development and has the potential to be applied to studies of ecological complexity. Here, we develop a set of thermodynamic indicators including energy capture and energy dissipation to quantify plant community self-organization. The study ecosystems included a tropical seasonal rainforest, an artificial tropical rainforest, a rubber plantation, and two Chromolaena odorata (L.) R.M. King & H. Robinson communities aged 13 years and 1 year. The communities represent a complexity transect from primary vegetation, to transitional community, economic plantation, and fallows and are typical for Xishuangbanna, southwestern China. The indicators of ecosystem self-organization are sensitive to plant community type and seasonality, and demonstrate that the tropical seasonal rainforest is highly self-organized and plays an important role in local environmental stability via the land surface thermal regulation. The rubber plantation is at a very low level of self-organization as quantified by the thermodynamic indicators, especially during the dry season. The expansion of the area of rubber plantation and shrinkage of tropical seasonal rainforest would likely induce local surface warming and a larger daily temperature range.     

1991年华南地区热带气旋灾害概况

本文介绍了1991年在我国登陆的6个热带气旋灾害的特点及其所造成的人员伤亡与经济损失。     

Political benefits as barriers to assessment of environmental costs in Brazil's Amazonian development planning: The example of the Jatapu Dam in Roraima

Development projects are rapidly changing the landscape in Brazilian Amazonia. Environmental impact assessments have been required since 1986, and the regulatory system is evolving as precedents are set by each new development project. The Jatapu Dam in Roraima provides an illustration of underlying impediments to assessment of environmental costs and to due consideration being given to these assessments when decisions are made. The high priority placed on the dam by the Roraima state government is unexplainable in terms of economic returns. The place of the dam in a long-term political strategy provides the best of several possible explanations, any one of which is incompatible with a rational weighing of economic and environmental costs and benefits. A number of lessons can be drawn from the experience of Jatapu, but some of the problems have no solution. The barriers to rational decision making illustrated by Jatapu apply to development projects in many parts of the world.     

Methodology for identifying vulnerability hotspots to tropical cyclone hazard in India

Vulnerability indices are commonly used for characterizing the impacts on a region or comparing relative vulnerability across regions. Such indices are usually computed as a composite/aggregate across different components of vulnerability. Though such a single numerical value can be useful in many situations, a major disadvantage is that it leads to loss of information about how the different factors that went into making the composite index interact with each other, and contribute to making a place vulnerable. In this paper we develop an alternative approach for identifying hotspots, based on cluster analysis that seeks to address this problem by considering the different components of vulnerability separately. We compute different indices for each of the components of vulnerability. Cluster analysis helps in identifying the most vulnerable districts based on different combinations of the components of vulnerability. In addition to being methodologically more robust than the index approach, the clustering approach may have greater policy-relevance as it provides information about which aspects of vulnerability, policy needs to address in the most vulnerable districts. An erratum to this article can be found at     

Floristic composition and vegetation ecology of the Malindi bay coastal dune field, Kenya

A short outline is given of the floristic composition, structure and distribution of coastal dune vegetation found at Malindi Bay, Kenya. The area was studied by air photo interpretation and field sampling to determine the relationship of plants to aeolian features. TWINSPAN classification was used to distinguish geomorphological units on the basis of their species composition. In this paper, an inventory and first quantitative analysis of vegetation distribution is presented. We identified 174 plant species from 62 families in the sand dunes and several plant communities are distinguished based on the species content and the connection with morphological units.Papilionaceae with 18 species andPoaceae with 17 species were the most represented families. A distinct zonal distribution of the plant communities was found. The most important plant species are the pioneer vegetation consisting ofHalopyrum mucronatum, Ipomoea pescaprae andScaevola plumieri. The woody shrub species which have colonized the established primary dunes and hummock dunes areCordia somaliensis, Pluchea discoridis, Tephrosia purpurea (dunensis). Succulent herbs were identified in the dune slacks and salt marsh that are moist and damp environments.     

Tropical montane cloud forests: current threats and opportunities for their conservation and sustainable management in Mexico

Tropical montane cloud forests (TMCF) are among the most threatened ecosystems globally in spite of their high strategic value for sustainable development due to the key role played by these forests in hydrological cycle maintenance and as reservoirs of endemic biodiversity. Resources for effective conservation and management programs are rarely sufficient, and criteria must be applied to prioritize TMCF for conservation action. This paper reports a priority analysis of the 13 main regions of TMCF distribution in Mexico, based on four criteria: (1) forest quality, (2) threats to forest permanence, (3) threats to forest integrity, and (4) opportunities for conservation. Due to the diverse socio-environmental conditions of the local communities living in Mexican TMCF regions, their associated social characteristics were also evaluated to provide a background for the planning of conservation actions. A set of indicators was defined for the measurement of each criterion. To assign priority values for subregions within each main region, an international team of 40 participants evaluated all the indicators using multicriteria decision-making analysis. This procedure enabled the identification of 15 subregions of critical priority, 17 of high priority, and 10 of medium priority; three more were not analysed due to lack of information. The evaluation revealed a number of subjects that had hitherto been undetected and that may prove useful for prioritization efforts in other regions where TMCF is similarly documented and faces equally severe threats. Based on this analysis, key recommendations are outlined to advance conservation objectives in those TMCF areas that are subjected to high pressure on forest resources.     

Self-organization of tropical seasonal rain forest in southwest China

How to measure development of ecosystems is both a theoretical and practical question in ecology. Species richness and biomass accumulation are familiar figures of merit, but they cannot be instant watched. Self-organization is a tacit character. However, methods to measure the degree of self-organization of ecosystem are problematic. To this end Lin et al. (2009) have devised indicators of energy capture and dissipation so that self-organization defined via maximum energy dissipation can be quantified easily. Here the method is used to analyze long-term data (2004-2006) of a tropical seasonal rain forest included in the ChinaFLUX program. Three years of average self-organization values were clearly separated by seasonal variation. Reflection and long wave radiation are the main two pathways of energy loss. For tropical seasonal rain forest studied, long wave radiation contributed most to energy loss, and was negatively correlated with energy capture ability (Rn/DR). The nocturnal difference between canopy and air temperatures had a strong negative correlation with the long wave radiation loss ratio. However, the long wave radiation loss ratio was slightly lower than the reflection loss ratio in rainy season, when values were very low. Precipitation and wind had significant impact on energy dissipation ability in the hot dry season, but the correlation coefficients between precipitation and wind with thermal response numbers (TRNs) were very low. The results indicated that the self-organization estimation system based on “maximum energy dissipation theory” is applicable for tropical forest.