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41.
Globally, the most widely used wetland classification is that adopted by the contracting parties of the Ramsar Convention, which is the Convention on Wetlands of International Importance especially as Waterfowl Habitat. A review of the Inland Wetland component of this system shows that mixed criteria are used to separate the wetlands, and that not all natural inland wetlands have been addressed. A classification system using landform and hydro-period, which results in 13 primary geomorphically non-emergent types for natural wetlands, is proposed to describe the full variety of wetlands at a primary level around the globe, and is suggested to be incorporated as the first-tier of the Ramsar classification.The proposed classification has been designed so wetlands can be described, classified and compared systematically. This paper attempts to reconcile the Ramsar Classification system with the proposed approach. The intention in this paper is not to displace the Ramsar Classification, but rather to indicate its inherent underlying geomorphic structure, and hence re-order its hierarchical framework. This adjustment to the existing classification system would highlight underlying similarities between wetlands so that global comparisons can be more readily made. It also has considerable advantages for a staged, systematic discrimination and classification of the vast array of differing wetlands globally.The use of geomorphic and hydrologic elements as the primary and secondary divisions with the more commonly used Ramsar Classification terms as a tertiary division, provides a logical structure to compare and contrast wetlands globally. 相似文献
42.
Conservation and management issues of Prespa National Park 总被引:1,自引:1,他引:0
The present article describes the human activities inthe area and their changes and trends, given that thecontemporary nature conservation key issues areclosely related to past and present socio-economic andcultural conditions, both within Prespa itself andoutside of it. The liberation of Prespa, a remote andrather socially isolated borderline area, from Ottoman occupation took place in 1912–13. Recentevents in its environmental history have been forestclearings and human depopulation in the Civil War(1944–49), irrigation system construction in the1960s, its discovery by ornithologists in the late1960s, the high emigration rates of 1960–1980, itsdesignation as a National Park in 1974, thedestructive development works of 1984–86 afterGreeces entry to the EEC and the conversion to intensivebean cultivation in the mid 1980s.The human population of ca 7000 at the start of thiscentury suffered an almost 80% decrease after theCivil War. A resettlement in the mid 1950s increasedthe population by 40% but in the 1970s emigrationreduced it to its previous size of around 1500, stillits present size. The extensive and diverse farmingsystems of previous centuries changed gradually afterthe construction of an irrigation network in the1960s, which twenty years later and along withinternational changes in production and economypatterns, made possible the present day domination ofa bean monoculture within irrigated croplands. Thiswas accompanied by increased energy inputs,mechanisation and the use of chemicals.Intensification of agriculture brought increasedincomes which attracted also livestock keepers,resulting in a 56% decrease in numbers of livestockin 1964–1993. Cattle are presently kept for meatproduction only. They graze on the mountains, and nolonger in the meadows around the lakeshore. A localshorthorn breed accounting for 93% of all cattle in1963 declined to less than 18% in 1993. Fishing aimedmainly at carp and Prespa bleak, continues today as inthe past to be a source of supplementary income.Eighty-six per cent of the – mainly oak and beech –forests are State owned and the rest belong to localmunicipalities. The forest area has not changedessentially in the last 40 years, but forest roadshave expanded. Forests provide mainly fuelwood forlocal needs and small quantities of industrial timber.No specific management is conducted to safeguard theconservation values of the forest, the majority ofwhich consists of even aged coppiced stands withlimited value for wildlife. Manufacturing never playedan important role for the economy of the area. Tourismhas increased in the last 20 years, concentratedmainly in summer and spring. Accommodation in thevillages is not yet satisfactory though it hasimproved enormously in recent years. The NationalParks infrastructure for visitors remains poor.Tourist pressure generally is not yet that high toimpact drastically the social and environmentalfabric. In places, hunting, angling and poaching cannegatively affect the target species. The constructionof the irrigation network in the eastern part of LakeMikri Prespa was the most important change to thelandscape and the habitats of Prespa the last 30years. It resulted in the embankment of free-flowingstreams, drainage of wet meadows and dramaticreduction of trees and hedges. In the last 15 years,the reedbeds, no longer burnt or mowed and assisted byincreased nutrient loadings from agricultural runoff,have expanded landward to occupy formerly open,periodically flooded, areas. The above changes inhabitats and land use have brought an impoverishmentof biodiversity which can be seen in the exterminationor the decrease in the numbers of certain plant andbird species.The problems preventing a better management of theNational Park and the perpetuation of its values areinappropriate legislation, the poor degree ofcoordination of the public services, the lack of botha specific National Park Service in Greece and amanagement authority for the Park and the hostileattitude of local people due to their limitedinformation and involvement. The scenic beauty, thewetlands and a number of rare habitats, the diversityof habitats, flora and fauna, the endemic life forms,the rare mammals and the colonial waterbirds, thelocal architecture and the cultural expressions suchas the Byzantine monuments, are the values of Prespathat must be preserved as a whole. The initialconservation efforts aimed at preserving biodiversitybut later it became apparent that not only are humansan inseparable part of the whole, but additionally,several of their extensive activities have contributedsubstantially to the rich biodiversity of the area.Through the prerequisites of keeping a balance betweenprimary and tertiary sector activities and ofrevitalizing the social fabric, the following are thekey management and conservation issues of today: anunequivocal agreement on the values to be preservedand their limits; the formation of a managementauthority; a new realistic protection and land usezoning; the diversification and extensification of allfarming activities; the restoration of the wet meadowhabitats; the ensuring of a high water level and agood water quality for both lakes through tri-lateralcooperation between Greece, Albania and FYROM; and theestablishment of a permanent environmental monitoringscheme. 相似文献
43.
高原鼠兔与达乌尔鼠兔食物资源维生态位的研究 总被引:19,自引:5,他引:14
作者于1993年在青海省刚察县年诺索玛地区发现高原鼠兔(Ochotona curzoniae)和达乌尔鼠兔(0.daurica)在布哈河谷二阶同域且重叠分布之现象,并从这两种鼠兔的食物资源利用出发,研究了其生态位关系问题。在食物资源维上的生态位宽度(PS),高原鼠兔为0.4744,达乌尔鼠兔为0.4964,即它们具有相近似的生态位宽度。这两种动物的生态位在食物资源谱维上的重叠值(FT)为0.809 相似文献
44.
黄土丘陵沟壑区水平梯田改土培肥增产技术措施体系 总被引:2,自引:0,他引:2
黄土丘陵沟壑区水平梯田改土培肥增产技术措施体系刘东海赵廷宁(宁夏西吉县农业局756200)(北京林业大学水土保持学院100083)赵国杰(宁夏西吉县农业技术推广站756200)TechniquesofSoilImprovementandYieldIn... 相似文献
45.
A review of the salt sensitivity of the Australian freshwater biota 总被引:13,自引:7,他引:6
Barry T. Hart Paul Bailey Rick Edwards Kent Hortle Kim James Andrew McMahon Charles Meredith Kerrie Swadling 《Hydrobiologia》1991,210(1-2):105-144
In Victoria, Australia, both dryland salinity and salinity in irrigation regions are serious agricultural problems. One option
to control the latter is to pump groundwater to maintain it below the surface. However, this leaves a saline wastewater for
disposal, probably into local streams or wetlands. This review of the salt sensitivity of the biota of Australian streams
and wetlands gives information of interest to those responsible for developing controls on these discharges. The review addresses
the lethal and sub-lethal effects of salinity on microbes (mainly bacteria), macrophytes and micro-algae, riparian vegetation,
invertebrates, fish, amphibians, reptiles, mammals, and birds. Data suggest that direct adverse biological effects are likely
to occur in Australian river, stream and wetland ecosystems if salinity is increased to around 1 000 mg L−1. The review highlights a general lack of data on the sensitivity of freshwater plants and animals to salinity increases. 相似文献
46.
黄土丘陵半干旱区不同作物生态效能研究 总被引:5,自引:0,他引:5
深入研究特定生态环境条件下不同作物生产力及其生态效能,对于合理调控农田生态系统,探讨提高系统生产力途径具有重要意义。60年代以来,在国际生物学计划(IBP)的影响下,美国、日本、菲葎宾等国先后进行了小麦、水稻、大豆等作物农田生态效能研究。我国于“六·五”期间分别在南方稻区、黄淮海平原以及北方灌区等不同农业区开展了多种作物种植制度生产力问题研究,并取得重 相似文献
47.
48.
49.
Jeong Ho Hwang Eunjoong Kim Eun Young Choi Jong Bong Choi Jong Kyun Park 《Entomological Research》2020,50(5):221-228
Gonggeom‐ji pond is the first protected paddy field wetland area, designated by the Ministry of Environment of Korea in 2011, because of its high biodiversity and historic value. It contains reservoirs, paddy fields, and a forest site that provides diverse niches for insects. Quantitative methods were used in this study to estimate the insect diversity of this region. A transect of 50 m was designated in each site (reservoirs, paddy fields, and a forest site). Data were collected using sweeping and pitfall traps along each transect in May, August, and November 2017, representative of the seasons—spring, summer, and autumn, respectively. As a result, a total of 1079 individual insects representing 170 species from 60 families within nine orders were collected. Diversity, richness, and evenness indices were the highest in the forest site in May (4.77, 8.6, and 0.91, respectively). The dominance index was the highest in the forest site in November (0.64). Similarity index was the highest in the reservoir in May and August (0.519). These results would help compare different sites and their vegetation to assess relationships between insects and habitats. 相似文献
50.