Vegetation Composition,Dynamics, and Management of a Bracken–Grassland and Northern–Dry Forest Ecosystem

We investigated differences in vegetation composition and dynamics for two globally rare ecosystems, bracken–grasslands and northern–dry forests of northern Wisconsin. These ecosystems commonly have been viewed as degraded pine barrens. Bracken–grasslands contained a high dominance of exotic species, low native richness, and no obvious prairie species, suggesting logging-era anthropogenic origins. Differences in cover for common plants among ecosystems were examined using Mann-Whitney U tests of equivalence. Cover of all 8 graminoid species, 4 of 5 Ericaceae and Myricaceae species, and 10 of 17 species of forbs were significantly different between ecosystems. Vegetation changes over a 4-year period were examined through detrended correspondence analysis (DCA) and analysis of variance (ANOVA) repeated measures. DCA analyses of community composition failed to detect significant temporal trends within individual management units, although differences were apparent between ecosystems, regardless of sample year. In addition, no apparent patterns could be detected between years when comparing dominant individual species to management history (prescribed fire). This is contrary to what would be expected for a degraded pine barrens and questions the efficacy of using repeated prescribed fire as a management tool in bracken–grasslands. Methods for conservation and restoration of xeric ecosystems of northern Wisconsin have historically relied heavily on single species (e.g., sharp-tailed grouse) wildlife models, without full consideration of other factors. We suggest that stakeholders involved in these restoration projects examine historic processes and reference conditions prior to formulating management goals. Greater attention to the differentiation and individual management needs of pine barrens, northern–dry forests, and bracken–grasslands is needed.     

Impacts of lands cover change on plant and bird species diversity in Hainan Island, China

--Hainan Island, located at the southern end of China, hasless than 0.4% of land area but contains 13% of plant and animalspecies in China. During the last four decades many primary forestshave been converted to shrub land, grassland, and tree planation(e.g., eucalyptus forest). As a result, area of primary tropicalforest has been reduced from 25.8% in the 1950s to 4% in the 1990s.To assess impacts of land conversion on plant and bird speciesdiversity, a series of samples in primary forest and four types ofconverted lands were took. The land conversion had tremendouslyreduced both plant and bird species diversity. Specifically, plantspecies richness per site was 83.7 in primary forest, 28.3 in shrubland, 12.5 in grassland, 14.4 in eucalyptus forest, and 21.4 inAcacia forest. Bird species richness showed a similar trend 22.0in primary forest, 14.5 in shrub land, 2.5 in grassland, 4.9 ineucalyptus forest, and 9.0 in Acacia forest. The Shannon speciesdiversity indices for plants in the five types of land cover were3.69, 1.99, 0.97, 1.47 and 2.07, respectively. Similarly, the Shannon indices for bird species diversity were the highest in primary forest, and lowest in grassland, and intermediate in shrubland and eucalyptus forest.     

在铅电解生产中如何减少铅烟尘的污染

铅电解阳极板制作之前 ,需对粗铅或残极进行熔化 ,在这个过程中会产生很多铅烟尘 ,如不对铅烟尘进行回收 ,就会污染周围的空气。有必要采用收尘装置 ,解决这一污染问题     

Indonesian peat and vegetation fire emissions: Study on factors influencing large-scale smoke haze pollution using a regional atmospheric chemistry model

Numerical modelling of fire-related smoke haze episodes in Southeast Asia is important for both prediction and assessment of atmospheric impacts, especially when observational data are fragmentary, as is the case in Indonesia. This work describes the atmospheric fate of smoke particles emitted during the 1997 Indonesian fires modelled with a regional atmospheric chemistry model. We established a new fire emission inventory and calculate that 55 teragram (Tg) of particulate matter and 1098 Tg of carbon were released during this fire episode. Our emission estimate is an intermediate value compared with other studies. Utilising different scenarios, we demonstrate the variable atmospheric impacts of surface vegetation fires and peat soil fires separately and also investigate the sensitivity of smoke dispersion to the differing meteorological conditions of an El Niño and a normal year. When peat fires are included in the emission inventory, modelled ambient particle concentrations exceed the ambient air quality standard across transboundary scales. In a scenario including only surface vegetation fires, ambient air quality standards are exceeded only in areas close to the main fires. This scenario demonstrates the prominent role of fires in peat areas in causing regional air pollution episodes. In years with normal meteorological conditions, intermittent precipitation and associated wet deposition during the dry season are predicted to remove most of the particulate emissions close to the sources. Strongly reduced rainfall and generally stronger southeasterly winds during El Niño years provide favourable conditions for larger scale smoke haze pollution.     

川中丘陵区荒坡利用方式对水土流失影响的研究

川中丘陵区荒坡面积占据一定比重,防治水土流失,合理利用荒坡水土资源,对发展本区经济起着重要作用。本文通过网点观测来探求合理利用方式,为荒坡开发利用提供决策依据。     

晋西南黄土高原区植被覆盖度变化及其生态效应评估

水土流失和生态退化是黄土高原区面临的严峻问题,已经严重制约了经济发展。基于TM和OLI数据,分别估算晋西南黄土高原区的植被覆盖度（FVC）和遥感生态指数（RSEI）,定量分析了晋西南黄土高原区的植被和生态恢复效果,并提出需要重点治理的区域。研究结果表明：（1）15年间晋西南黄土高原区的植被覆盖度和遥感生态指数都呈现增加的趋势,FVC指数从2002年的42.69%增加至2017年的47.67%,RSEI指数由2002年的45%增加至2017年的52.5%,反映出研究区生态质量有了明显提高;（2）除研究区内芝河流域、汾河谷地和沁河流域的生态质量出现严重退化外,研究区大部分区域的FVC指数和RSEI指数都呈改善趋势,因此需对芝河流域、汾河谷地和沁河流域加大生态治理力度;（3）除研究区汾河谷地外,其余地区植被覆盖度和遥感生态指数的变化趋势基本吻合,汾河谷地由于冬小麦大面积种植,植被覆盖度得到一定程度改善,但遥感生态指数并没有明显改善。     

化铜炉烟尘治理

攀 钢密地 机械厂有 ３ 台化铜 炉产生 烟尘 污 染车 间 空气。 针对 化 铜炉 冶炼 的 特点 选用 Ｌ Ｈ Ｆ－ Ⅱ２３０ Ａ 型 反吹扁 布袋 除尘器 对３ 台化铜 炉的烟 尘进 行集中 除尘， 设计 了带旋 转法 兰的捕 尘罩。使用结 果表明 ：该方法操 作灵活 方便，使用 效果良 好     

Impacts of land cover change on plant and bird species diversity in Hainan Island,China

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试论根据土壤生产潜力及土地利用强度评价土地利用合理性问题——以加拿大渥太华市郊为例

土地利用的合理性取决于土地利用强度是否与土壤生产潜力相适宜。土地利用强度等级与土壤生产潜力级别的一致性是一地区土地利用合理性的标志。依据作物系统编制的农业土地利用系统图较传统的土地覆盖图有更大的实用性。可利用该图与土壤生产潜力图迭加制成的农业资源分区图来分析1978—1987年渥太华市郊土地利用的合理性。结果指出,渥太华市郊土地利用方式基本上是合理的,变化趋势也是适宜的,但同时有不足之处,建议当地市政当局对某些不合理的土地利用方式做相应调整。     

生物反应器填埋场临时覆盖材料的选择探讨

生物反应器填埋场要求临时覆盖材料具有较强的渗透能力和一定的均衡回灌渗滤液流动的能力。通过比较,认为生物反应器填埋场在运营前期宜采用粉质砂土、黄土或轻亚粘土作临时覆盖材料,后期采用稳定垃圾分选的细粒物作临时覆盖材料,在雨季时还可配合使用塑料布防止过多的降水进入场内。