Bison and elk in the American Southwest: In search of the pristine

Ecosystem managers often use the early historic condition of the fauna in an area as the model for restoration or management. West of the Pecos River in the American Southwest, present-day abundances and distributional ranges of bison and American elk exceed those reported in early historic times. I evaluate several potential causes for the historic scarcity of these animals—inadequate forage, insufficient water, nonhuman predation, disease, and hunting by late-prehistoric humans. Archaeological and ecological evidence suggest that restricted availability of water coupled with hunting by late-prehistoric peoples probably were the most important causes. Perennial water is more widely distributed now than previously, mainly because of water well and water catchment construction. Proliferation of agriculture-based human economies in the region from AD 0–1500 led to rapid population growth of aboriginal peoples, with resulting increased harvests of resources. The likelihood that late-prehistoric humans severely depleted the abundances of large mammals indicates a need to reevaluate the exclusive use of early-historic conditions as the basis for setting goals for ecosystem management. Implications of reintroducing large herbivores to ecosystems are discussed.     

TOTAL SOLUTES LOADS AND GEOCHEMICAL YIELDS IN THE SASKATCHEWAN RIVER BASIN1

ABSTRACT: River solute loads have seldom been measured in very large, complex drainage basins, nor have the methods of calculating loads been critically examined. For sites in the Saskatchewan River Basin, Canada, rating curves were poor predictors of solute loads because correlations between discharge and total solutes concentration were weak (R² < 0.05 in most cases) and suffered from hysteresis. In contrast, the interval method produced reliable estimates in all seasons and sites tested, and was little affected by sampling schedule. The limit of precision (SE) for estimates of mean annual or seasonal solute load was 10–15 percent of the mean (5 percent in very small basins), reached with 10 years or more of data. Two-thirds or more of total annual solute load was transported during the open-water season, but the proportion carried during winter increased from 8 percent to 34 percent from the upstream to the downstream end of the basin, due to reservoirs retaining and mixing water. Annual loads of total solutes varied from 6.2 × 10⁴ tonnes in foothills tributaries to almost 4.0 × 10⁶ tonnes in the Saskatchewan River near the mouth. But, on an areal basis, the mountain and foothills region was the dominant solute source, producing 43–97 tonnes/km²/yr, compared with only 3–22 tonnes/km²/yr for prairie rivers. This difference is a consequence of greater rainfall and, hence, more rapid erosion in the mountains.     

关于环境监测成本核算的探讨

本文针对目前科技体制改革与市场经济发展的现状，主要探讨了环境科研监测部门在全企业做好服务的基础上，如何加强成本管理，怎样进行成本核算，认真按照收费标准合理收费，从而实现环境监测与市场收费的协调发展。     

USING VALUES IN PLANNING WASTEWATER FACILITIES FOR METROPOLITAN SEATTLE1

ABSTRACT: This paper uses the fundamental values of decision makers to guide a long-term wastewater planning process at Seattle Metro, a major utility district. Multiattribute value assessment is used to elicit the objectives of several elected officials and other key decision makers. The results are structured into a fundamental objectives hierarchy and a means-ends objectives network. A set of measures to indicate the performance of planning alternatives in terms of the fundamental objectives is developed. Preliminary value tradeoffs between objectives are elicited from several elected officials. The results of these steps are useful for many aspects of long-term planning: facilitating communication about values and priorities; designing attractive alternatives that are more likely to serve stakeholder interests; identifying information needed to evaluate alternatives; clarifying the relative importance of information about different impacts; providing a basis for quantitative evaluation of the alternatives with multiple objective analysis; and focusing attention on key tradeoffs that will affect the choice of alternatives.     

COUNTY COMMISSIONERS' WATER KNOWLEDGE1

ABSTRACT: This study examines the social construction of county commissioners' knowledge about water. Factors that influence what commissioners know about water include each commissioner's personal characteristics, education, experience in natural resources management, involvement in policy making, and use and evaluation of various sources of information. This study focused on county commissioners representing rural, mixed, and urban counties in Arizona, Nevada, and Utah and collected data through mail surveys and interviews. County commissioners in the survey were well educated; however, few had taken college courses directly addressing technical, management, or legal aspects of water issues. Approximately one-third had direct experience in farming and ranching; nearly two-thirds indicated that farming and ranching played a major role in their communities. Respondents had experience with a broad range of water policy issues. In evaluating thirteen information sources in terms of their frequency of use, relevancy, and reliability, respondents assessed fellow commissioners and local government staff and managers most positively and nonprofit organizations most negatively. The media was also broadly rated as less relevant and reliable than other sources of information. The commissioners in the study expressed a high level of general concern about water issues and a strung preference for local sources of information.     

Predicting Plant Extinction Based on Species-Area Curves in Prairie Fragments with High Beta Richness

Abstract:  Species-area relationships and island biogeography theory are commonly used to predict how species richness will decline with fragmentation. There are a variety of largely untested assumptions in these approaches, including the assumptions that populations are distributed uniformly before fragmentation, and that local extinctions are due to effects of small population sizes. If populations are not distributed uniformly, then populations can be abundant locally but rare globally. This would cause extinction rates to be smaller than predicted. We tested extinction theory by developing estimates of the number of plant species that should be present in small tallgrass prairie fragments and then testing the uniformity assumption by partitioning species richness into α (within site) and β (among site) components in Iowa prairies. Many more native prairie plant species were present in surveys of prairie fragments (491) than was predicted based on theory (27–207). A large proportion (75%) of the total species richness was β richness. We suggest that the high proportion of β richness was responsible for the shallow species-area slopes and the lower than expected number of species losses and that a better understanding of what determines β diversity will improve predictions of fragmentation effects on richness of plants. We also suggest that plants in prairie remnants may be best conserved by protecting different prairie types rather than by protecting a few large areas containing a single prairie type.     

高活性阳极制备及阿莫西林降解中的毒性效应

采用电流调控方式制备多催化位点的高效Ti/PbO₂阳极，并对其形貌、晶型、电化学性能等进行表征，以常见抗生素阿莫西林（AMX）作为目标有机物，考察了阿莫西林在电催化降解中的毒性演变过程.结果表明，随沉积电流密度梯级升高，电极表层形貌由“四棱锥型”向“菜花状”转变，但晶相仍为β-PbO₂，同时电极伏安电荷量提高，膜阻抗降低.毒性检测结果表明，水体中AMX浓度与斜生栅藻的藻密度呈负相关，但对其叶绿素合成表现为“低浓度促进，高浓度抑制”效果.此外，优选制备电极对AMX具有较好的降解效果，AMX水体毒性水平随电催化降解呈现先升高后降低趋势，转录效应指数TELI_total值由最初1.54升至2.61，并经150min的持续电催化降为1.63.经110种基因应激结果表明，AMX在电催化降解中造成的细胞氧化应激与蛋白质应激最为明显.     

规格性与功能性安全法规的分析比较

功能性（或目标设定）安全法规只是提出应达到的目标而不规定实现这些目标的具体措施。本文对规格性（或描述性）与功能性安全法规进行了分析、比较,提出了目前的规格性安全法规存在的问题和功能性安全法规的优点;介绍了后者在一些国家中的成功实践;分析了风险或安全分析在功能性安全法规的实施过程中的作用。     

SCIENCE AND POLICY IN INTEGRATED WATERSHED MANAGEMENT: A CASE STUDY1

ABSTRACT: Policy and management plans can be enhanced through effective communication between researchers and decision makers. Differences in understanding can come from differences in professional cultures. Scientists deal with facts, proof and incremental progress whereas the decision makers are often faced with perceptions, emotions and deadlines. A case study is presented illustrating the interaction between the political system and science on a water management issue. Irrigation projects in the western San Joaquin Valley of California lead to a situation requiring subsurface drainage and disposal of the drainage water. The original plan was to discharge the drainage water in the Suisun Bay east of the San Francisco Bay. Severe damage to birds associated with selenium in the water led to a reevaluation of irrigation and drainage management options. Federal and state agencies cooperated to establish a San Joaquin Valley Drainage Program (SJVDP) which was to develop plans for solving the problem. Discharge to the Bay was politically eliminated as an option for evaluation, an action criticized by a National Research Council Committee as not being scientifically based. The SJVDP published a Management Plan in 1990 which contained proposals viewed by the scientific community as not necessarily incorrect but not completely justified based on the scientific knowledge at the time. A segment of the Citizens Advisory Committee that was part of the SJVDP consisting of representatives from the interest groups viewed the Management Plan as a negotiated agreement between the environmental and agricultural interests. Presently, an Activity Plan exists, consisting of technical committees to evaluate the current technical and economic evaluation of the management options proposed in the Management Plan. This case study illustrates that factors other than scientific facts have bearing on decisions. Successful management plans must be technically sound, economically viable and socially acceptable. The scientific community needs to evaluate its role in the policy making arena and to focus research on questions of greatest value to decision makers, as well as to scientific peers.     

中国化肥资源供需矛盾及调控策略

鉴于中国化肥供需形势不清给产业调控带来不确定性影响,论文分析了化肥资源供需矛盾,并提出了相关调控策略。结果表明,中国化肥供需总量已经接近平衡,氮磷钾化肥的自给率分别达到100%、95%和29%。少部分产品存在缺口,其中氯化钾的自给率为23%,是当前我国惟一紧缺的化肥产品。随着化肥生产向资源产地集中,中国化肥供需时空不平衡有扩大的趋势。部分时间段的供需不平衡异常尖锐,其中10月份至来年3月份全国化肥供应过剩超过900×10⁴t,而部分月份却极端不足,例如7月份两广、东北等地的尿素缺口达200×10⁴t左右,10月份华北地区的磷酸二铵缺口达到100×10⁴t左右,而5、7、8三个月中两广地区的钾肥缺口也超过100×10⁴t。建议国家加强储备工作,储备化肥消费量的15%,其中10%储备在淡季,以减少过剩的压力,而5%储备在旺季,以应对市场供不应求。