湿地需警惕的外来入侵物种

<正>湿地同森林和海洋一样,是地球上三大生态系统之一,与人类关系十分密切,被誉为"地球之肾",在维护全球生态平衡、促进经济社会发展等方面发挥着不可替代的作用。同时,由于地表径流影响、人为活动干扰等因素,湿地也是容易遭受外来物种入侵的生态系统,许多外来入侵物种,给我国湿地环境造成了     

华侨城湿地外来入侵物种及防治施工设计

外来物种入侵目前已成为威胁湿地生态状况的五大主要因子之一。以华侨城湿地为例,调查发现该湿地入侵植物12科23属26种,入侵动物2科2属2种;并提出了外来入侵物种防治施工设计的目标、原则、技术要点、验收标准,具有一定借鉴意义。     

西溪湿地外来植物及其风险管理

采用经典分类及群落学研究方法,通过实地调查和资料分析,对西溪湿地外来植物,特别是外来入侵植物的种类、生境、危害程度等进行了研究。结果表明:西溪湿地现有外来种子植物97科234属328种,其中被子植物91科220属311种。菊科、禾本科和蔷薇科等14科所含属种是该地外来植物的主要组成部分,菊科、禾本科占绝对优势;菊科外来植物在外来种中所占比例大,且危害较重。景观改造、湿地植物园引种是西溪湿地外来植物种类大量增加的主要原因。西溪湿地现有外来入侵植物共27科55属71种,原产地为美洲的48种,占总种数的67.61%;原产地为欧洲的9种,占12.68%。外来入侵植物以一年生或二年生草本居多,有52种,占总种数的73.24%,落叶灌木仅1种(占1.41%)。提出西溪湿地外来植物的编目、监测和数字化管理的建议,并建议将美丽飞蓬、南美天胡荽、再力花和黄菖蒲等4种外来植物列入中国外来入侵植物名录。     

洞庭湖区入侵植物的物种组成、区系特征和分布北大核心CSCD

为了加强对洞庭湖区入侵植物的管理,2019年11月7日至2021年5月31日期间,在东、西和南洞庭湖区,开展了入侵植物野外实地调查;结合筛查到的文献资料,对野外调查记录的入侵植物物种名单进行了补充。研究结果表明,洞庭湖区有入侵植物35科82属107种;有26科83种入侵植物为恶性入侵、严重入侵、局部入侵和一般入侵物种,其中,恶性入侵、严重入侵、局部入侵和一般入侵物种的数量分别为19种、24种、15种和25种;在调查的入侵植物物种中,有25种菊科植物,占洞庭湖区入侵植物总物种数量的23.36%;有70种入侵植物的原产地为美洲,占洞庭湖区入侵植物总物种数量的65.42%,有22种入侵植物的原产地为欧洲,占20.56%;在东、南和西洞庭湖区分别记录了20科47种、31科74种和18科48种入侵植物;洞庭湖区入侵植物科的特征区系以世界广布为主,世界广布入侵植物科的数量占总科数的51.43%;入侵植物属的区系分布则主要集中在世界分布和泛热带分布两种类型,其入侵植物属的数量分别占总属数的24.39%和23.17%;入侵植物物种表现出明显的热带区系特征;与以往记载的入侵植物物种数量相比,目前洞庭湖区的入侵植物物种数量明显增加,表明外来植物的入侵与扩散速度迅猛,因此,应该加大对洞庭湖洲滩上外来入侵植物的防控力度。     

梅州城市湿地外来入侵植物现状及防治对策

通过实地调查和文献检索,对梅州城市湿地外来入侵植物的组成、生活型、危害程度、原产地、入侵途径等进行了分析。结果表明：梅州城市湿地主要外来入侵植物有16科29属33种,其中菊科植物的数量最多,占入侵植物总数的27.3%;生活型以草本植物为主;有10种入侵植物给当地生态环境带来严重危害;原产地以美洲为主;引入途径主要以人为有意或无意引入为主。在分析城市湿地外来入侵植物现状的基础上,提出了建立入侵植物生态风险评估系统、加强入境检疫、加强地区合作、提高公众防范意识、有效防控和变害为宝等对策,为城市生态及经济的可持续发展提供参考。     

广州市主要河流中22座未开发江心岛上的入侵植物种类及其分布特征

分布于流溪河等河流中未开发的江心岛具有生态和文化等多重价值,这些未开发的江心岛是广州市碧道建设实施方案中的重点保护对象。外来入侵植物是江心岛生态系统健康发育的潜在危害因素。为了全面掌握广州市主要河流中未经市政开发的江心岛上的入侵植物分布状况,通过现场调查和查阅相关文献资料,研究了广州市珠江水系中22座未开发的江心岛上的入侵植物种类和分布特征。研究结果表明,在22座未开发的江心岛上,共记录11科26属27种入侵植物,这些物种都为广州市已经记录的入侵植物物种,其中,菊科(Compositae)物种(10种)最多;白花鬼针草(Bidens pilosa)在11座江心岛上分布,光荚含羞草(Mimosa bimucronata)在10座江心岛上分布,薇甘菊(Mikania micrantha)、马缨丹(Lantana camara)和南美蟛蜞菊(Sphagneticola trilobata)的分布也较广;东江流域的泊鹤洲上的入侵植物物种(11种)最多,其次为南航道的屎船沙(10种);白花鬼针草、南美蟛蜞菊、薇甘菊、光荚含羞草、五爪金龙(Ipomoea cairica)和原野菟丝子(Cuscut...     

杭州西溪湿地资源现状与保护对策

杭州西溪湿地是平原水网地区自然—人工复合湿地生态系统的典型代表。在对西溪湿地野外调查的基础上,阐述湿地类型与分布、动植物资源、旅游资源、水资源等特征,分析西溪湿地面临的主要问题,提出湿地资源保护和修复对策。结果表明:西溪湿地面积546.45 hm~2,植物696种、植物群落87个;脊椎动物257种,其中鸟类181种、兽类6种、爬行类7种、两栖类7种、鱼类56种;无脊椎动物172种,其中原生动物28种、原腔动物55种、环节动物32种、水生软体动物25种、陆生软体动物29种、节肢动物3种;代表性旅游资源和景点127个。湿地主要面临水质污染、外来物种入侵以及高强度人为干扰的威胁,亟需采取污染源控制、破碎化生境修复、生态状况动态监测等措施保护和修复湿地生态系统。     

利用土壤种子库的湿地植物恢复研究概述北大核心CSCD

受损湿地生态系统的植物恢复与重建是湿地研究的热点。土壤种子库是退化湿地的植物自然恢复的潜在植物种子来源。总结了利用土壤种子库的湿地植物恢复研究成果,梳理了湿地植物恢复技术路线,重点综述了原位恢复和异位恢复方法、影响湿地植物恢复效果的因素及其评价指标体系;评述了水文条件和养分对湿地植物恢复效果的影响;在此基础上,提出了今后湿地植物恢复研究应侧重于土壤种子库技术与其它技术的结合、非目标种和外来入侵物种的控制与去除、植物恢复后长期管理措施的有效性、关键土壤理化特性指标调控等方面。     

利用土壤种子库的湿地植物恢复研究概述

受损湿地生态系统的植物恢复与重建是湿地研究的热点。土壤种子库是退化湿地的植物自然恢复的潜在植物种子来源。总结了利用土壤种子库的湿地植物恢复研究成果,梳理了湿地植物恢复技术路线,重点综述了原位恢复和异位恢复方法、影响湿地植物恢复效果的因素及其评价指标体系;评述了水文条件和养分对湿地植物恢复效果的影响;在此基础上,提出了今后湿地植物恢复研究应侧重于土壤种子库技术与其它技术的结合、非目标种和外来入侵物种的控制与去除、植物恢复后长期管理措施的有效性、关键土壤理化特性指标调控等方面。     

杭州西溪湿地灌草群落组成的季节变化

采用随机取样、定点调查的方法,分析杭州西溪湿地灌草植物群落的类型与时间、空间的关系,并用多样性指数分析春、夏、秋、冬四季中植物群落组成的特点.结果表明,西溪湿地物种对时间生态位的利用比较充分,四季中群落组成有较为明湿的变化;春季物种最为丰富,9 m2中达29种,香农一威纳指数H'为2.73,与其他季节相比差异显著;冬季物种最少,为11种,H'为2.14;夏秋季物种多样性介于春、冬季之间.西溪湿地的现有植物组成是人与自然因素共同作用的结果,而人的影响更大.西溪湿地典型的湿地物种偏少,外来有害入侵物种的比例较高,建议在去除影响景观、影响本土物种多样性的入侵种的同时,增加低湿的生境,并补种湿地物种.     

FRIENDS OR FOE? INVASIVE SPECIES AND PUBLIC GREEN SPACE IN TORONTO

ABSTRACT. Environmentalists and ecologists typically regard invasive species as ecologically detrimental and undesirable. Although the ecological impacts of invasive species are well documented, less attention has been devoted to the sociocultural contexts guiding responses to species invasion. In this study the roles of invasive species are reconsidered through three prominent green spaces in Toronto, Canada: the Don Valley Brick Works, High Park, and the Leslie Street Spit. The case studies challenge popular negative assumptions about invasive species and suggest that they can serve important functions both for local ecosystems and for human communities. The case studies also provide lessons on the tension between and within different environmental imaginaries informing invasive species management. Invasives are often compatible with recreational interests, whereas naturalization efforts are ecologically sensitive and costly. Invasives can help restore human‐made wastelands, and naturalization efforts often benefit wealthy rather than poor neighborhoods.     

COMPARING INVASIVE NETWORKS: CULTURAL AND POLITICAL BIOGRAPHIES OF INVASIVE SPECIES*

ABSTRACT. Under what cultural and political conditions do certain species become successful invaders? What impact does species invasion have on human culture and politics? The work assembled in this special issue of the Geographical Review suggests complex interspecies interactions that complicate any answer to these questions. It demonstrates the need to advance a more integrative human/environment approach to species invasion than has hitherto been seen. Reviewing the concepts demonstrated in these articles and applying them to case histories of Mimosaceae (a family that includes genera such as Acacia, Prosopis, and Mimosa) invasion, two general principles become clear. The status and identification of any species as an invader, weed, or exotic are conditioned by cultural and political circumstances. Furthermore, because the human “preparation of landscape” is a prerequisite for most cases of invasion, and because species invasions impact local culture and politics in ways that often feed back into the environmental system, specific power‐laden networks of human and non‐human actors tend to create the momentum for invasion. It is therefore possible to argue a more general cultural and political account of contemporary species expansion: It is not species but sociobiological networks that are invasive.     

Impact of prescribed burning on Acacia nilotica seed banks and seedlings in the Astrebla grasslands of northern Australia

Acacia nilotica is a tree of international significance both as a beneficial plant and as a species prone to thicket formation and negative impacts on savannas throughout much of its range. While fire has been identified as a useful tool for controlling negative impacts of some Acacia species in Africa, A. nilotica adult trees are apparently fire tolerant. The effects of fire on seed bank mortality, viability and germination, and on juvenile plants of this species are unknown. We undertook a study to investigate the impacts of fire on seeds and first and second year seedlings in Australian Astrebla savannas. The primary objective was to determine the effects of control burns applied during the early stages of invasion and thicket formation. Because of high rates of seedling dessication post fire in 1997, supplementary watering was undertaken until fire mortality could be measured the following year. High seed mortality occurred for seeds located either in cattle dung (100%) or on the soil surface (c. 80%). Germination of those seeds that survived was enhanced following exposure to fire. Very high fire mortality (99%) was observed among first year seedlings and moderate mortality (60%) for second year seedlings even after a low intensity burn. Negative impacts on major pasture species were minimal. The implications of these findings are discussed in relation to A. nilotica fire ecology and to the efficacy of fire as a tool for managing this species.     

土库曼斯坦物种多样性及其与中国新疆的比较

土库曼斯坦与中国新疆在地理地形、景观带以及气候特征等诸多方面具有相似之处,这些因素共同决定了二者在物种多样性方面的相似性与可比性,加之人类活动影响加剧,两地物种多样性均遭受着严重的威胁。在对土库曼斯坦和中国新疆现有物种多样性数据进行总结的基础上,分析了二者的物种多样性现状、珍稀动植物特征以及濒危种和入侵种相关研究进展,对比了二者在物种多样性年际尺度上的异同,总结了土库曼斯坦与中国新疆物种多样性保护现状与相关政策,以期为深入开展两地生物多样性合作与交流提供支持。     

Soil Property Differences Between Invaded Casuarina (Casuarina equisetifolia L.) Sites and Non-Casuarina Sites in the Bahamas

Casuarina (Casuarina equisetifolia) is a problematic invasive species within the Bahamas, associated with numerous environmental problems. Previous studies suggest casuarinas establish ecologically sterile monocultures, yet there is limited research on whether soils from casuarina-dominated sites differ physically or chemically from comparable soils under native vegetation. Because of the lack of knowledge and because this invader has the potential to be detrimental to native ecosystems, we conducted a study to examine differences in soil properties between sites where casuarinas dominated versus sites where casuarinas were absent. Soils at casuarina-dominated sites had lower potassium, phosphorus, and organic matter concentrations and had lower pH levels. But, casuarina-dominated sites had significantly higher leaf-litter abundances. No significant differences between soils were detected for calcium concentrations, magnesium concentrations, cation exchange capacity, nitrate-nitrogen concentrations, or soil moisture levels. A multivariate ordination showed that casuarina-dominated soils were more similar to one another than to non-casuarina soils. Thus, soil characteristics from casuarina-dominated areas appear to differ from comparable habitats devoid of casuarinas. There are at least two possible explanations: certain soil properties may have been more conducive to casuarina invasions, or casuarinas may have modified their soils once they became established. The results of this study provide insights into the invasion process and add to our understanding of how these invaders affect native Bahamian ecosystems.     

The Coyote Brush Invasion of Southern California Grasslands and the Legacy of Mechanical Disturbance

This study investigates the recent invasion of exotic grasslands by coyote brush in La Jolla Valley, California. We test the “event dependent” hypothesis that mechanical disturbances during the past century were a key cause. To examine the relationship between past mechanical disturbances and vegetation dynamics we first conducted a review of the historical literature on practices of shrub removal and documented disturbance history using historical imagery. We next analyzed vegetation‐cover change over time using remotely sensed imagery and a vegetation map to document the history of native shrub advancement into exotic grassland by species association. Finally, we determined the topographic characteristics associated with different phases of shrub advancement. We found that mechanical disturbances historically varied by topography with upper and steeper slopes being least intensively disturbed. We found that shrub advancement rates, following release from grazing, varied by slope, elevation, and time period, and that Baccharis pilularis (coyote brush) was the main species to invade the more intensively disturbed sites at lower elevations. Our results indicate that mechanical disturbances played an important role in modifying the original vegetation cover with long‐lasting consequences, including a facilitating role for the subsequent Baccharis pilularis invasion. We concluded that the practice of grazing often included exotic mechanical disturbances that had long‐lasting impacts on native plants.     

ENERGY SOURCES FOR EVAPORATION ON TROPICAL ISLANDS

The sources of energy for evaporation on tropical islands were explored by studying 49 lowland sites in the Hawaiian Islands with concurrent pan evaporation and solar radiation measurements. The Priestley-Taylor (1972) method was used to quantify the contribution of solar radiation in evaporation and the residual term between estimated and measured evaporation was attributed to heat advection. Pearson correlation coefficients between monthly measured and estimated evaporation (using solar radiation data) were greater than 0.95 at 26 of the sites, 0.90 for 37 sites, and 0.80 at 46 of the 49 sites used in the study. As expected, solar radiation supplies the bulk of the energy absorbed by evaporation at low elevations in Hawaii. However, a pattern of negative advection in summer and positive advection in winter from the surrounding ocean modifies the monthly evaporation values. For the 20 sites showing the greatest oceanic influence, departures ranged, on average, from +0.84 mm/day in November to -0.71 mm/day in June. This onshore advection corresponds to the seasonal lag in sea surface temperatures. At inland and wet lee sites, the effect of advection from oceanic sources diminishes. At dry lee sites, strong positive advection is evident in summer and autumn, enhancing evaporation by up to 2.8 mm/day. [Key words: evaporation, energy, tropical islands, radiation, advection]     

外来入侵植物分布格局及与环境和人为因子的关系——以五个自然保护区为例(英文)

以5个保护区为例来探究外来入侵植物与环境及人为因子间的关系。利用CCA分析了环境变量与外来入侵植物丰度的关系,采用了多元回归得出了与外来入侵植物最为相关的环境与人为因子。结果显示,从泰山自然保护区到丰林自然保护区,外来入侵植物分别为25种、12种、13种、5种、5种,沿着包括纬度、最高温度,最低温度、最高降雨量等环境因子强度的降低而下滑。而同时,外来入侵植物的数量随着人为活动的干扰度增强而增加。从起源上来看,热带成分从31%降至0,而北美起源的植物则逐渐增加。从科的组成上看,五个自然保护区中均有菊科分布,所占比例分别为15%、33%、36%、 40% 和20%,显示了其世界广布的特性,而其他科属入侵植物的分布并不均衡。从生活型上看,一年生或多年生草本植物为主要成分。外来入侵植物的传入途径在很大程度上受人类活动及利用喜好的驱动。     

Invasive Saltcedar (Tamarix): Its Spread from the American Southwest to the Northern Great Plains

The advance of saltcedar from the American southwest to Montana between the mid-19th and mid-20th centuries crossed the Continental Divide—a major topographic and climatic barrier to natural dispersal by southern plants. Interviews, archival information, and field observations are used to explain this advance. According to archival documents, saltcedar was planted in communities adjacent to the Bighorn River in central Wyoming as part of urban beautification projects in 1936. Bureau of Reclamation reports describe tree plantings for erosion control between 1940 and 1953 within the Riverton Irrigation Project in the Wind-Bighorn River watershed. These introductions were followed by rapid natural dispersal northward by water and wind through the Wind/Bighorn system and into the Yellowstone and Missouri rivers in Montana before closure of Boysen and Bighorn dams in 1951 and 1967. Construction equipment and ornamental plantings further transported saltcedar to the Fort Peck Reservoir and the Musselshell River. We conclude that, without control at its advancing fronts, a complete ban of its sale, and removal of existing ornamental and erosion control trees, saltcedar will invade most suitable sites in the Missouri watershed and disperse northwards into western Canada.