Analysis of the Threshold and Expected Coverage Approaches to the Probabilistic Reserve Site Selection Problem

Two approaches to formulating the reserve site selection problem when species occurrence data is probabilistic were solved for terrestrial vertebrates in a small set of potential reserve sites in Oregon. The expected coverage approach, which maximizes the sum of the occurrence probabilities, yielded solutions that covered more species on average in Monte Carlo simulations than the threshold approach, which maximizes the number of species for which the occurrence probability exceeds some threshold.     

A national ozone biomonitoring program--results from field surveys of ozone sensitive plants in northeastern forests (1994-2000)

Ozone biomonitoring is a detection and monitoring techniquethat involves documenting ozone-induced visible injury toknown ozone-sensitive species under conditions of ambientexposure. The USDA Forest Service administers a long-term,nationwide ozone biomonitoring program to address public andscientific concerns about ozone impacts on forest health. Asystematic grid is used as the basis for biomonitoring sitelocations. At each site, trained field crews evaluate amaximum of thirty plants of up to six species and record the amount and severity of leaf-injury on individualplants. Injury from ozone was found more often on biomonitoring sites in the eastern Unites States than in theinterior or west-coast areas. Further results from thenortheast reveal that in any year, there is a higherpercentage of ozone-injured plants with more severe symptomsin areas with relatively high ozone concentrations than inareas with relatively low ozone. In very dry years (e.g.,1999) the percentage of injured plants and injury severityestimates are both sharply reduced even though ambient ozoneexposures are high. These findings demonstrate thatbiomonitoring data provide meaningful evidence of when highozone concentrations during the growing season have biologicalsignificance. Any assessment of ozone stress in the forestenvironment must include both biomonitoring (i.e., plantresponse) and air quality data to be complete.     

水和废水中硫的电化学形态分析方法

参阅国内外文献，对近年来水和废水中硫的电化学形态分析方法进行了评述，重点介绍了现代极谱法在海洋孔隙水，缺氧湖水，造纸废水，硫化物矿浮选废水、电影洗印厂废水及地面水中硫形态分析上的应用；并归纳出，极谱法优于其他化学分析方法，对水溶液中硫的存在形态及其相互转化也作了简单介绍。     

Climatic and Environmental Changes in the Source Areas of Dust Storms in Xinjiang, China, during the Last 50 Years

The desert environmental changes in the source areas of dust storms occurring in Xinjiang are discussed based on the climate changes and the impacts of human activities in Xinjiang during the past 50 years. The results show that the climate in Xinjiang is changing from a warm-dry type to a warm-wet one. The warm-wet climate has been obvious since the mid-1970's, and especially the sensitivity of the regional climate change in this arid area is obviously revealed by many factors, such as the characteristics of the local climate change in south Xinjiang and north Xinjiang, the difference of climate change in the alpine zones and the basins, and the change of areas of the waters bodies. Furthermore, these factors also reveal the difference in the regional climate change between Xinjiang and central and eastern areas of China. The occurrence and development of dust storms are directly affected by the precipitation, air humidity, status of underlying surface, etc. in the arid areas. The frequency and intensity of dust storms are closely related to the natural conditions, changes of climate and desert environment, as well as the dynamic conditions (i.e., weather systems) in the source areas of dust storms. Therefore, global warming is one of the main causes resulting in the degradation of the ecological environment and the frequent occurrence of natural disasters, especially the disasters of sand drift and dust storms in the arid areas since the late-1980's, which reveals that the inland arid areas are sensitive regions to climate changes.     

Do Non-Native Species Threaten The Natural Environment?

Conservation biologists and other environmentalists confront five obstacles in building support for regulatory policies that seek to exclude or remove introduced plants and other non-native species that threaten to harm natural areas or the natural environment. First, the concept of “harm to the natural environment” is nebulous and undefined. Second, ecologists cannot predict how introduced species will behave in natural ecosystems. If biologists cannot define “harm” or predict the behavior of introduced species, they must target all non-native species as potentially “harmful”. an impossibly large regulatory task. Third, loss of species richness may constitute harm to an environment, but introduced organisms typically, generally, and significantly add to species richness in ecosystems. If species richness correlates with desirable ecosystem properties, moreover, such as stability and productivity, as some ecologists believe, then introduced organisms, by increasing species richness, would support those desirable properties. Fourth, one may plausibly argue that extinction constitutes environmental harm, but there is no evidence that non-native species, especially plants, are significant causes of extinction, except for predators in certain lakes and other small island-like environments. Fifth, while aesthetic, ethical, and spiritual values may provide a legitimate basis for invasive species policy, biologists often cite concepts such as “biodiversity” and ecosystem “health” or “integrity” to provide a scientific justification. To assert that non-native species threaten biodiversity or undermine ecosystem health, however, may be to draw conceptual entailments or consequences from definitions of “biodiversity” and “integrity” that arbitrarily exclude non-native species or make the presence of exotic species a per se indicator of decline.     

Impacts of Recreation Trails on Exotic and Ruderal Species Distribution in Grassland Areas Along the Colorado Front Range

This study examines the establishment patterns of exotic and ruderal species along trail corridors in grassland areas of the Colorado Front Range. The effects of trail presence, trail age, and trail traffic levels on exotic and ruderal species establishment are explored to ascertain the potential impacts of trails on surrounding vegetation. Established trails exhibited a greater presence of exotic and ruderal species along the immediate trailside, showing that disturbed trailsides tend to encourage the growth of these species over time. Furthermore, the established trails exhibited significantly less native, nonruderal, and overall species richness at the trailside. These trailside patterns did not show a significant spread away from the trail edge, even after prolonged time periods. Finally, higher trail use tended to hasten the establishment of exotic species along the trailside. The trails did not introduce new species to the recreation areas; rather they acted as reorganizational tools for species that were already present in the study sites.     

The Effect of Military Training Activity on Eastern Lupine and the Karner Blue Butterfly at Fort McCoy,Wisconsin, USA

The US Department of Defense (DOD) manages over 10.1 million ha of land, much of which is used for training military personnel. However, vast sections receive little or no use, and military lands have become refuges for many species. At Fort McCoy, Wisconsin, USA, populations of the endangered Karner blue butterfly (Lycaeides melissa samuelis) are found in oak and pine barren communities where wild lupine (Lupinus perennis), a perennial forb required by Karner blue butterfly larvae, still occurs. Oak and pine barren communities are disturbance-dependent, and the barrens ecosystems in the Midwest have declined in extent by 98% because of fire suppression, succession, and habitat fragmentation. We studied the effects of disturbance by military manuever training on the density of lupine and Karner blue butterfly at Fort McCoy. We also wanted to determine whether military training activity could enhance Karner blue butterfly habitat. At locations where tracked vehicles had driven through lupine patches, the abundance of lupine and nectar-producing plants was greater in the median strip between vehicle ruts than in vehicle ruts or 5 m outside the vehicle ruts. The proportion of lupine stems with Karner blue butterfly larvae feeding sign (the ratio of stems fed upon to stems examined) was greater in areas where military vehicles had traveled than where they had not. The proportion of lupine stems with feeding sign and lupine stem density was also positively related to the occurrence of prior bivouacs and fires caused by military munitions. Shrub and forest canopy abundance were lower in areas traveled by tracked vehicles. At the scale of the lupine patch, lupine abundance and the proportion of lupine stems with feeding sign were positively correlated with military training activities, suggesting that maintenance of lupine habitat can be achieved in concert with military training.     

Biodiversity Conservation in the Thar Desert; with Emphasis on Endemic and Medicinal Plants

The Indian desert, the Thar Desert, has its own importance and specific characteristics with respect to endemic and medicinal plants. Forty-five plant species are considered to be rare and/or endangered. The desert has a large number of plants of economic importance and medicinal use. The Thar Desert is thickly populated in comparison to other hot deserts of the world. 17.44 million people and 23.33 million livestock are recorded from the region. These populations exert pressure on the biological resources of the Thar Desert causing a lack of sustainability and necessitate conservation of biodiversity actions.     

Conservation of Biodiversity: How Are We Doing?

A question rarely raised in discussions on biodiversity conservation, but surely the biggest question of all, is “How much time do we have left before the mass extinction underway surpasses our best efforts to contain it?” This prompts a further prime question because—and unlike all other problems, whether environmental or otherwise—the biotic crisis threatens to leave a severely impoverished planet for millions of years ahead; “Why do we not undertake the necessary actions to get on top of the problem before it gets on top of us?”     

试论荒漠生态监测的特点和监测指标的确定

从监测目的、监测对象、监测指标和监测数据的获取四个方面,论述了进行荒漠生态环境监测工作的特点.从干旱荒漠区自然环境的基本特征和主要生态环境问题及生态环境管理工作的需要出发,提出了在我国开展荒漠生态环境监测工作的监测指标,以供商榷.