摘要
在气候变化和人类活动的双重影响下,一些湿地严重退化。其中,流域干旱问题是导致湿地退化的重要原因之一。干旱严重制约着湿地的生态水文过程。一方面,干旱通过造成湿地水量亏缺和水分条件改变,来影响湿地生物和生境条件;另一方面,湿地中的生物对干旱具有一定的适应性,通过个体的形态、生理和行为适应等来避免干旱造成的伤害;同时,这一过程还伴随着生物种群的数量、密度、生物量、分布以及群落的组成、数量、生物量、分布等特征的变化;最终干旱对湿地的影响将体现在湿地规模、构成、格局和功能的变化上。在理论上,干旱作为一种扰动对提高湿地生态系统的耐旱性有一定积极影响,但由于缺少长期的湿地恢复过程研究,这一学术观点并未被广泛认知;长时间的严重干旱则会对湿地生态系统产生不可逆转的影响,导致其退化、消失。
Under the double effect of climate change and human activities,wetlands degenerated a lot.Among them,basin drought is one of the important reasons which lead to the degradation of wetland.In the context of drought,regional water scarcity making the ecological water use of wetland further diverted;in particular,during drought,acute shortage of water making the self-recovery capacity of wetland reduced,or even lost,which restricts the eco-hydrological process of wetland seriously.Basin drought is one of the extreme hydrological events which has a significant impact on wetland ecosystem.As a driving force,it forms pressure through changing wetland water condition and causing water scarcity,so as to make impact on organisms and habitat of wetland.To the freshwater lake wetland,this alteration mainly reflected on water level,water area,biomass and biodiversity.On the other hand,there is adaptability of organisms in the wetland,they can avoid the damage of drought by individual biomorphic,physiological and behavioral adaption;at the same time,this process also following alteration of the quantity,density,biomass,distribution of population and the composition,quantity,biomass,distribution and other characteristics of community;finally,this influence of drought will present on the scale,composition,landscape pattern and function of the wetland.As an ecosystem with characteristics both aquatic and terrestrial,a wetland may have the ability to stay stable and adapt to changing situations.Beside the internal factors,the ability of the wetland ecosystem to adapt to regional drought depends on the severity and duration of drought.As a disturbance,drought has a positive impact on enhancing the tolerance of wetland ecosystem to drought and may improve the biodiversity.In this point,moderate drought will improve the tolerance of the wetland plants to drought.However,the long-time severe drought may have an irreversible impact on the wetland ecosystem which makes the wetland vegetations couldn＇t keep up with it and the structure of plant community change,causing the disappearance of dominant species and constructive species,changing the original landscape thus leads its deterioration or disappearance.And the superimpose effect of natural drought and human activities made the extent of damage of the wetland more serious and decreased its adaptability and recovery capability further up.At present,the responding work to drought not only failed to integrate the water demand of wetland effectively,but also overdeveloped water resources of the wetland as an emergency source,which accelerated the processes of ecological degradation of the wetland.So,we should establish the protected object of the wetland,and compensating water according to the self-recovery capacity of the wetland under different drought scene.For this purpose,we may assist some mechanical control measures to sustain the normal eco-hydrology processes and take some measures to guarantee the emergency/security water supply.There are some major practice needed in the wetland protection：first,we should systematically identify the influence mechanism of the wetland under the background of basin drought and the self-recovery capacity of the wetland in different contexts;second,put forward the protected object and its ecological water requirement threshold;third,integrate water requirement for the wetland into the whole schedule when responding to basin drought.
出处
《湿地科学》
CSCD
北大核心
2012年第4期396-403,共8页
Wetland Science
基金
国家重点基础研究发展计划项目课题(2010CB951102)
国家自然科学基金创新研究群体基金项目(51021006)资助
关键词
流域干旱
淡水湖泊湿地生态系统
影响机制
basin drought
freshwater lake wetland ecosystem
mechanism of influence
