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781.
The ability to predict which alien plants will transition from naturalized to invasive prior to their introduction to novel regions is a key goal for conservation and has the potential to increase the efficacy of weed risk assessment (WRA). However, multiple factors contribute to plant invasion success (e.g., functional traits, range characteristics, residence time, phylogeny), and they all must be taken into account simultaneously in order to identify meaningful correlates of invasion success. We compiled 146 pairs of phylogenetically paired (congeneric) naturalized and invasive plant species in Australia with similar minimum residence times (i.e., time since introduction in years). These pairs were used to test for differences in 5 functional traits (flowering duration, leaf size, maximum height, specific leaf area [SLA], seed mass) and 3 characteristics of species’ native ranges (biome occupancy, mean annual temperature, and rainfall breadth) between naturalized and invasive species. Invasive species, on average, had larger SLA, longer flowering periods, and were taller than their congeneric naturalized relatives. Invaders also exhibited greater tolerance for different environmental conditions in the native range, where they occupied more biomes and a wider breadth of rainfall and temperature conditions than naturalized congeners. However, neither seed mass nor leaf size differed between pairs of naturalized and invasive species. A key finding was the role of SLA in distinguishing between naturalized and invasive pairs. Species with high SLA values were typically associated with faster growth rates, more rapid turnover of leaf material, and shorter lifespans than those species with low SLA. This suite of characteristics may contribute to the ability of a species to transition from naturalized to invasive across a wide range of environmental contexts and disturbance regimes. Our findings will help in the refinement of WRA protocols, and we advocate the inclusion of quantitative traits, in particular SLA, into the WRA schemes.  相似文献   
782.
The growth, development and consumption of successive three generations of cotton bollworm, Helicoverpa armigera (Htibner), fed on cotton bolls grown under elevated CO2 (double-ambient vs. ambient) in open-top chambers were examined. Significant decreases in protein, total amino acid, water and nitrogen content and increases in free fatty acid were observed in cotton bolls. Changes in quality of cotton bolls affected the growth, development and food utilization of H. armigera. Significantly longer larval development duration in three successive generations and lower pupal weight of the second and third generations were observed in cotton bollworm fed on cotton bolls grown under elevated CO2. Significantly lower fecundity was also found in successive three generations of H. armigera fed on cotton bolls grown under elevated CO2. The consumption per larva occurred significant increase in successive three generations and frass per larva were also significantly increased during the second and third generations under elevated CO2. Significantly lower relative growth rate, efficiency of conversion of ingested food and significant higher relative consumption rate in successive three generations were observed in cotton bollworm fed on cotton bolls grown under elevated CO2. Significantly lower potential female fecundity, larval numbers and population consumption were found in the second and third generations of cotton bollworm fed on cotton bolls grown under elevated CO2. The integrative effect of higher larval mortality rate and lower adult fecundity resulted in significant decreases in potential population consumption in the latter two generations. The results show that elevated CO2 adversely affects cotton bolls quality, which indicates the potential population dynamics and potential population consumption of cotton bollworm will alleviate the harm to the plants in the future rising CO2 atmosphere.  相似文献   
783.
污水处理厂的排放污泥是诸多污染物的最终环境归宿之一,其环境影响值得重视。在江苏省全境调查了49家化工园区集中式污水处理厂,对其外排污泥及其浸出液中的5种重金属(砷、镉、铬、汞和铅)含量进行了测定,采用Hakanson潜在生态危害指数法评价了污泥中重金属生态风险。结果表明:49家化工园区污泥浸出液中5种重金属均不超标,但污泥中的砷、铬、汞含量超标,超标率分别为24.5%、6.1%和4.1%,最大超标倍数分别为131、2.12和0.41。污泥中砷含量显著高于我国城市污泥,潜在生态风险程度呈现汞砷铬。从地域分布来看,苏北地区化工园区污泥重金属风险更大。  相似文献   
784.
为了研究小水电站对河流底栖动物群落结构的影响,于2011年7月(丰水期)和2012年4月(枯水期)对云南景谷河底栖动物进行了两次调查,共采集底栖动物61种,隶属34科54属,其中寡毛类2科7属7种,软体动物7科7属7种,水生昆虫22科44属44种,其他动物3种。景谷河丰水期底栖动物平均密度为1 1353 ind./m2,生物量为793 g/m2,枯水期的密度为1 2316 ind./m2,生物量为692 g/m2。河蚬(Corbiculafluminea)、纹石蛾(Hydropsyche sp.)和多足摇蚊(Polypedilum sp.)在丰水期和枯水期均为优势种。功能摄食类群上收集者个体数量较多,约占50%,其余3个类群约占50%。景谷河梯级小水电站对底栖动物群落结构影响较大,小水电站的修建使景谷河生境分为库区、减水段、混合段等三类,分析表明库区底栖动物所受影响最大,减水段次之,混合段受影响较小。对景谷河与澜沧江干流的底栖动物进行了比较,探讨了形成底栖动物分布现状的原因,并提出了几种河流生境恢复策略  相似文献   
785.
Standardized test protocols are used in the regulatory context for identifying the hazardous properties of chemicals, wastes, and contaminated materials. This paper compares the relevance of two guidelines measuring effects on terrestrial plants, the OECD TG 208 and the ISO TG 22030 and presents the scientific basis for a recent decision of the European Chemicals Agency (ECHA) under the European chemicals regulation REACH. If there are no specific phytotoxicity alerts, both guidelines are considered suitable for assessing long-term hazards, providing that a sufficient number of species is included in the OECD protocol, the recommended minimum number is six, which offer a reasonably broad selection of species to account for interspecies sensitivity. The proposed methodology, based on a combination of probabilistic assessments using Monte Carlo analysis, can be adapted for supporting similar decisions under specific regulatory processes; for example, for assessing contaminated soils or pesticides’ applications.  相似文献   
786.
Abstract: Globally, ecosystems are under increasing anthropogenic pressure; thus, many are at risk of elimination. This situation has led the International Union for Conservation of Nature (IUCN) to propose a quantitative approach to ecosystem‐risk assessment. However, there is a need for their proposed criteria to be evaluated through practical examples spanning a diverse range of ecosystems and scales. We applied the IUCN's ecosystem red‐list criteria, which are based on changes in extent of ecosystems and reductions in ecosystem processes, to New Zealand's 72 naturally uncommon ecosystems. We aimed to test the applicability of the proposed criteria to ecosystems that are naturally uncommon (i.e., those that would naturally occur over a small area in the absence of human activity) and to provide information on the probability of ecosystem elimination so that conservation priorities might be set. We also tested the hypothesis that naturally uncommon ecosystems classified as threatened on the basis of IUCN Red List criteria contain more threatened plant species than those classified as nonthreatened. We identified 18 critically endangered, 17 endangered, and 10 vulnerable ecosystems. We estimated that naturally uncommon ecosystems contained 145 (85%) of mainland New Zealand's taxonomically distinct nationally critical, nationally endangered, and nationally vulnerable plant species, 66 (46%) of which were endemic to naturally uncommon ecosystems. We estimated there was a greater number of threatened plant species (per unit area) in critically endangered ecosystems than in ecosystems classified as nonthreatened. With their high levels of endemism and rapid and relatively well‐documented history of anthropogenic change, New Zealand's naturally uncommon ecosystems provide an excellent case‐study for the ongoing development of international criteria for threatened ecosystems. We suggest that interactions and synergies among decline in area, decline in function, and the scale of application of the criteria be used to improve the IUCN criteria for threatened ecosystems.  相似文献   
787.
SUMMARY

In India, since ancient times, several members of the flora and fauna have been identified with particular personalities of the Hindu pantheon and are worshipped. Many wild animals, such as tigers, lions and elephants, and birds such as the peacock, owl and swan have been revered as the vehicles of Gods and Goddesses and worshipped. Several trees, such as mango, coconut, khejri, emblica, tamarind, ashoka, madhuca and wood apple, and herbs such as basil are considered highly sacred and worshipped. This belief and these practices continue in one form or another even today in certain sections of Indian society, particularly the rural folk and the aboriginal tribes living in the forest. Nature worship is a form of tribal belief and the faith of these laymen has helped to conserve many natural ecosystems in India. They have preserved many pristine forests—called ‘sacred groves’ in their original forms. Sacred groves are rich in biodiversity. They are the last refuge of the rare flora and fauna which have otherwise disappeared from the modern world. Sacred groves have become part of the ‘biosphere reserves’ of India.  相似文献   
788.
789.
园林植物清除细菌能力的研究   总被引:32,自引:0,他引:32  
为筛选出除菌能力较强的园林植物,应用撞击平皿法采用内膏蛋白胨琼脂培养基进行样品采集与培养,通过多元素方差分析方法确定测定值的可比条件,对园林植物清除空气中细菌的能力进行比较研究。结果表明,园林植物具有较强的清除细菌能力,其能力大小在不同种类间具一定差异;其中,一串红、接骨木、火炬树、京桃、树锦鸡儿等植物除菌率小于40%,落叶松、圆柏、垂榆、加杨、华北柽柳、鸡冠花、黑心菊等除菌率为40%~80%,油  相似文献   
790.
耐寒人工湿地植物石龙芮和酸模联用研究   总被引:3,自引:0,他引:3  
为了提高人工湿地在寒冷季节的运行效率,对2种非夏季植物作为湿地植物处理生活污水的可行性进行了研究。结果表明,在本实验条件下2种植物对N、P元素都具有很好的去除效果,对COD的去除也达到45%~50%。通过单一植物系统和复合植物系统的处理效果比较,发现石龙芮酸模复合植物系统对污水中的P元素和COD的去除率更高。研究表明,石龙芮和酸模作为人工湿地植物具有可行性,与常规植物互补使用能在一定程度上延长人工湿地的运行时间。  相似文献   
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