Watershed development in India. 1. Biophysical and societal impacts

This paper recommends a revision of watershed development policy in India in relation to the planning of development interventions involving agricultural intensification and rainwater harvesting following biophysical and societal impact studies carried out on two watershed development projects in Karnataka. A need for changes in policy has arisen in response to progressive catchments closure at the basin level and declining volumes of water flowing into village level reservoirs (known locally as tanks). Flow reductions have occurred largely as a result of increased agricultural intensification over the past 10–15 years. Field levelling, field bund construction, soil water conservation measures, farm ponds, the increase in areas under horticulture and forestry and the increased abstraction and use of groundwater for irrigation are all contributing factors to reduced flows. Planning methodologies and approaches, which may have been appropriate 20 years ago for planning water harvesting within watershed development projects, are no longer appropriate today. New planning approaches are required which (1) take account of these changed flow conditions and (2) are also able to take account of externalities, which occur when actions of some affect the livelihoods of others who have no control or influence over such activities and which (3) contribute to the maintenance of agreed minimum downstream flows for environmental and other purposes.

Group leadership depends on energetic state in a nomadic collective foraging caterpillar

Group living is a common strategy among animals and has arisen independently in over 300 species of Lepidoptera. Yet, activity synchrony between individuals is necessary to derive the benefits that ensue from an aggregated lifestyle. Which individuals decide which activities to perform and when to perform them is, therefore, a fundamental question. In some species of social caterpillars and sawflies, the role of a potential behavioral polyethism between individuals has been suggested, whereby certain individuals are consistently more likely to initiate and lead a foraging event. However, in these cases, evidence in support of division of labor is lacking. This study was undertaken to determine if certain individuals of Malacosoma disstria are more likely to be consistent group leaders or if transient leaders could be predicted by the differences in energetic states between individuals. The results of this study indicate that unfed caterpillars initiate foraging bouts and are more likely to lead locomotion. There was no size or sex-based bias in those individuals that acted as temporary leaders. Consistent behavioral differences between individuals, if they exist, are therefore not necessary to explain task allocation and synchronization during foraging in this species.     

Reactions of 2,4,6-trichlorophenol on model fly ash: oxidation to CO and CO2, condensation to PCDD/F and conversion into related compounds

Thermal treatment of 2,4,6-trichlorophenol on a magnesium silicate-based model fly ash in the temperature range between 250 degrees C and 400 degrees C leads predominantly to carbon monoxide and carbon dioxide. The fraction of 2,4,6-trichlorophenol which is oxidized to CO and CO2 increases from 3% at 250 degrees C to 75% at 400 degrees C. Further products are polychlorinated benzenes, dibenzo-p-dioxins, dibenzofurans and phenols. The homologue and isomer patterns of the chlorobenzenes suggest chlorination in the ipso-position of the trichlorophenol. The formation of PCDD from 2,4,6-trichlorophenol and 2,3,4,6-tetrachlorophenol on municipal solid waste incinerator fly ashes and model fly ash were compared and the reaction order calculated.     

Are rivers just big streams? A pulse method to quantify nitrogen demand in a large river

Given recent focus on large rivers as conduits for excess nutrients to coastal zones, their role in processing and retaining nutrients has been overlooked and understudied. Empirical measurements of nutrient uptake in large rivers are lacking, despite a substantial body of knowledge on nutrient transport and removal in smaller streams. Researchers interested in nutrient transport by rivers (discharge >10000 L/s) are left to extrapolate riverine nutrient demand using a modeling framework or a mass balance approach. To begin to fill this knowledge gap, we present data using a pulse method to measure inorganic nitrogen. (N) transport and removal in the Upper Snake River, Wyoming, USA (seventh order, discharge 12000 L/s). We found that the Upper Snake had surprisingly high biotic demand relative to smaller streams in the same river network for both ammonium (NH4+) and nitrate (NO3-). Placed in the context of a meta-analysis of previously published nutrient uptake studies, these data suggest that large rivers may have similar biotic demand for N as smaller tributaries. We also found that demand for different forms of inorganic N (NH4+ vs. NO3-) scaled differently with stream size. Data from rivers like the Upper Snake and larger are essential for effective water quality management at the scale of river networks. Empirical measurements of solute dynamics in large rivers are needed to understand the role of whole river networks (as opposed to stream reaches) in patterns of nutrient export at regional and continental scales.     

Connectivity or demography: Defining sources and sinks in coral reef fish metapopulations

The identity of an individual patch as a source or a sink within a metapopulation is a function of its ability to produce individuals and to disperse them to other patches. In marine systems patch identity is very often defined by dispersal ability alone—upstream patches are sources—while issues of variable habitat quality (which affects local production) are ignored. This can have important ramifications for the science of marine reserve siting. This study develops a spatially explicit source–sink metapopulation model for reef fish and uses it to evaluate the relative importance of connectivity versus demography and how this depends upon the level of local larval retention and the strength of density-dependent recruitment. Elasticity analyses indicated that patch contribution (source or sink) was more sensitive to demographic parameters (particularly survival) than connectivity and this effect was conserved even under strong levels of density-dependence and was generally strengthened as local retention increased. Variability in the relationship between parameter elasticity and local retention was shown to be dependent upon the magnitude of connectivity for an individual patch relative to a critical connectivity value. The proportion of larvae lost due to transport processes was an important parameter which directly affected the magnitude of this critical connectivity value. Patches with connectivity values less than the critical value contributed to the metapopulation largely via production (i.e., local demographics most important). As local retention increased, so did the importance of demographic parameters in these patches. Patches with connectivity values greater than the critical value contributed largely via dispersal of larvae and thus the importance of local demographics decreased as local retention increased.     

Monitoring and adaptive management: resolving social and organisational issues to improve information sharing in natural resource management

Adaptive, or 'learning by doing', approaches are often advocated as a means of providing increased understanding within natural resource management. However, a number of organisational and social issues need to be resolved if these approaches are to be used successfully. A case study in the South Island high country of New Zealand is used to review what is needed to support an ongoing community-based monitoring and adaptive management programme. First, the case study is described, paying attention to the social context of the resource management problem. The results of a workshop that explored this problem are then outlined, along with a proposed information flow suggested by participants. Requirements for future steps to resolve these problems (such as information protocols and a multi-stakeholder information system) are discussed. Finally, some broad lessons are drawn from this exercise that could help others developing similar approaches.     

Environmental pollution of China to foreign investors: detrimental or beneficial?

Environmental Science and Pollution Research - This study investigates the dynamic linkage among foreign direct investment, energy consumption, and environmental pollution of China spanning from...     

Song as a pursuit-deterrent signal,and its occurrence relative to other anti-predation behaviours of skylark (Alauda arvensis) on attack by merlins (Falco columbarius)

Skylarks show a range of anti-predation behaviours including flocking, refuge-seeking and song. Responses by skylarks to merlin attack were recorded over three winters on a Scottish estuary to determine the effectiveness of song as a pursuit-deterrent signal, and its use with respect to other anti-predation options such as flocking. Mortality due to merlin predation was high. Skylarks used song as a pursuit-deterrent signal. Merlins chased non- or poorly singing skylarks for longer periods compared to skylarks that sang well. A merlin was more likely to catch a non-singing than a poorly singing than a full-singing skylark. Temperature did not affect chase lengths, song types or success rates of attacks. Larger flocks of skylarks were preferentially attacked so that the individual probability of being attacked within some larger flock sizes was greater than in a smaller flock. Success rate did not vary with flock size. Merlins chose skylarks before any song was heard, so there was no cost for non-singing skylarks in joining flocks. The frequency of capture on merlin attack depended on the escape response used by the skylark. Non-singing skylarks were probably more likely to escape by seeking a refuge or staying on the ground on attack, while singing skylarks were more likely to escape if they flew. The optimal escape option available to a skylark on merlin attack was probably dependent on its condition, as indicated by its ability to sing on attack.     

瑞典四大湖泊(梅拉伦、哈马伦、韦特恩和维纳恩湖)研究工作40年:监测与治理措施对于社会可持续发展的重要意义

对瑞典的梅拉伦、哈马伦、韦特恩和维纳恩等四个大湖水质进行的监测已差不多有40年了.对湖泊的物理化学参数、浮游生物和底辆无脊椎动物进行了定期评估.对湖泊的水文和沉积条件、大型植物、鱼类、原始有机物产率、细菌和附生藻类进行了定期调查.人类活动(包括工业活动)的影响表现在湖中有机质、养分、金属和持久性有机化合物过量增加.从60年代末开始,对这些湖泊汇水区内所有市政污水处理厂都进行了更新改造,使其达到了最高技术标准(包括磷的化学沉淀处理),因而污水处理厂的磷排放减少了90%-95%.此外还对工业企业作出了规定,要求它们减少有害物质的排放.本文讨论了对湖泊采取活污措施后湖泊的变化情况以及各种指标达到的水平.这些研究有助于制定全国性湖泊监测计划.另外,通过大湖监测取得的成果有助于制定国家水质标准,包括物理、化学和生物学标准.