Research On Impacting Factors Of Submerged Plants Communities Restoration And Related Techniques In Yilong Lake,yunnan Province

Yilong lake is one of the nine plateau lakes in Yunnan.In recent years,with the process of urbanization accelerating,the water quality of the Yilong Lake gradually deteriorated,the succession of the submerged macrophyte community was accelerated,and the ecological appearance of the lake gradually disappeared.In order to control the eutrophication of the different lakes To enhance the protection of wetland ecological diversity,Honghe Environmental Protection Bureau to strengthen the protection and restoration of wetland vegetation in different lakes,especially the protection and restoration of submerged Plants.Unlike other eutrophic lakes,The Yilong lake is in the conversion point of grass lake to algal lake,In the West Lake area,the submerged plants are abundant and the water is clear.It is a typical grass lake.The submerged plants in the East Lake area are less distributed,the water is turbid and the algae density is high.It is a typical algae lake.Research on transformation of lakes on the node,the impact factor research of submerged plant recovery,prevention and control of eutrophication and the submerged plants recovery and protection has special research meaning.In addition,Ottelia is China's unique national endangered species,is the 3 national key protected plants,more is the history of dominant species in Yilong lake.Therefore,the study of restoration factor and recovery technology of submerged plant,to restore t dominant species of submerged plants communities,is the core content of the ecological protection in Yilong lake.The main content of this research focus on the submerged plants community remediation impact factors andremediation technology.We investigate and analyze on the water environmental factors of Yilong lake all around and main river into lake.And we explore the main influencing factors of Yilong lake‘s submerged plants community remediation by correlation analysis of submerged plants community structure characteristics and water environment factors.Yilong lake‘s submerged plants community remediation aim to restore the original natural ecology according to historical data analysis.Remediating eel grass and ottelia acuminata community is the main purpose of Yilong lake‘s submerged plants community remediation.Thus,this paper is based on the research conclusion of main environment factors.And we test and verify the effect influence factors on the remediation of eel grass and ottelia acuminata separately in the purposiveness research way.We explore the remediation technology which are used for the two submerged plants in Yilong lake.Besides water level of Yilong lake is declining year by year,and it‘s one of the main driving force in submerged plants community reduction.After 2012,Environmental Protection Agency carried out the work of returning farmland to lake.Most of the lakeside wetlands become abandoned farmland,while water loss and soil erosion is getting worse and worse.In order to remediate the lakeside wetlands,administration is imperative to promote the water level in Yilong lake.Thus,this paper research the effect fluctuation of water table on submerged plants community structure in Yilong lake in the background.And we explore the possibility of remediating submerged plants by artificial control water level.At last,we summary and analyze the research result of the influencing factors of submerged plants remediation.In the view of technology,we improve stress factor for supporting practical technical measures to remediate submerged plants.And we support technical and theoretical guidance for Yilong lake‘s submerged plants community remediation.The main results of this study:1?the Relationship between the Current Structure and Environmental Factors of the Submerged Plant Communities of Yilong LakeThrough the water quality investigation of the main river into lake and west-east lake,we find that total nitrogen?total phosphorus ? ammonia nitrogen in river are richer than west-east lake‘s,and there are significant water quality difference compared to lake area.There are significant water quality difference between east lake and west lake,while west is better than east.There are significant difference in submerged plants‘ space distribution between east lake and west lake.In west lake,the dominant sociales are Najas minor and bladderwort,while the dominant sociales are potamogeton pectinatus? Myriophyllum verticillatum and Najas marina in east lake.Besides,the cover degree?biomass and species richness of submerged plants in west is higher than east.The space distribution?the cover degree?biomass of Yilong lake‘s submerged plants are affected by water environment factors significantly.And the depth of water ?pellucidity? dissolved oxygen are the main influencing factors.Through a circannual monitoring,the pellucidity of east and west Yilong lake is stable.Under the condition of invariable in pellucidity,the difficulty in remediating the submerged plants brought by water depth become the first problem need to be solved for Yilong lake‘s submerged plants community remediation.2?The Impact of Water Depth Gradient on the Restoration of Vallisneria Natans Communities of Yilong LakeWater depth have significant effect on eel grass‘s plant height,fresh weight,leaf number,root length,growth rate and survival ratio.In different water-course,there is a significant correlation between sunlight strength and eel grass daily relative growth rate(r=0.935),there is a significant correlation between dissolve of oxygen and eel grass survival ratio(r=0.975).And plant height,fresh weight and other biological indicators are changing following the change of water depth correspondingly,while in 0.5m and 1.0m eel grass didn‘t show obvious inhibition,in 1.5m eel grass showed certain inhibitio,in 2.0m eel grass showed negative growth.Biological index including H2O2?CAT?MDA change following the change of the water depth.The activity of CAT have effectiveness in preferential answering for adverse environment,MDA‘s content is highly consistent with the force degree of plants.And it verify the growth of eel grass in the view of physiology.So we suggest that Yilong lake‘s submerged plants community remediation should develop in shallow area under 1.5m to get remediation.3? The Impact of Water Depth Gradient on the Restoration of Ottelia Acuminate Communities of Yilong LakeOttelia acuminata‘s growth and Photosynthetic fluorescence characteristics respond to water depth positively.Ottelia acuminata will change its growth feature and organization structure for photosynthesis with the change of water depth in order to adapt to the different water depth growth environment.There is no significant difference between Initial fluorescence F0 and maximum fluorescence Fm in different water depth,while maximum quantum yield Fv/Fm and fluorescence parameters Fv/F0 are increasing significantly with water depth increasing.There is significant difference in initial slope(?)?maximum electron transfer rate(ETRmax)? Half saturation intensity(EK)of light response curve in different water depth.It shows that efficiency of photosynthesis in ottelia acuminata leaves ? PS? system increase significantly in different water depth.Light harvesting ability of ottelia acuminata leaves don‘t have great change in different water depth,while ottelia acuminata improve the photosynthetic ability under low light through increase the amount of chl.a?chl.b and Car in leaves.Ottelia acuminata have different response mechanism in different water depth.Ottelia acuminata leaves in shoal area have a more excellent highlight protection mechanism,while Ottelia acuminata leaves in profundal zone have more excellent photosynthetic potential.Ottelia acuminata will adjust their biological form and physiological condition constantly following the change of water depth to adapt to complicated environment.Now in the condition of Yilong lake water environment,1.0 m is the most suitable water depth for ottelia acuminata remediation.4?The Impact of Fluctuation of Water Levels on the Structure and Succession of the Submerged Plant Communities of Yilong LakeThe change of water levels have significant effect on Yilong lake‘s submerged plants community structure.Submerged plants‘ species?biomass?cover degree have different degree of response to the change of water level.In the low transparency water,great enhancement of the water level will bring about the decrease of species?biomass?cover degree,even submerged plants community will decline or dead.The high transparency water bring relatively small impact.Under not the most suitable water level condition,submerged plants get more perfect sunlight through increase plant height in short time.And it decrease the consumption of material and energy under the condition of effective resources through decreasing the amount of the branch to adapt to the new water level.Through the comparative analysis of east-west lake,we find that the change of sunlight in different water level is the main driving factor of the effect which water level have on submerged plants.The change of water level have significant effect on Yilong lake‘s submerged plants‘ space distribution and succession of community.With the enhancement of water level,Yilong lake‘s submerged plants‘ space distribution move to the shoal area whose datum mark is more high.And species number is decreasing in community in profundal zone,while species number is increasing in shoal area.Yilong lake can take advantage of ubmerged plants seed bank and control measures of water level to remediate the lake‘s submerged plants community,and control the easy flooding reed and typha angustifolia community to achieve the goal of eutrophia‘s prevention and cure.5? A Study of the Restoration Technology of the Submerged Plant Communities of Yilong LakeBased on the ecological survey?historical data and the visiting and the investigational study,based on the theory of lake ecological remediation,Taking Yilong lake‘s development as a blueprint,we put forward the repertoire of Yilong lake‘s submerged plants community remediation by consulting similar cases about prevention and cure of eutrophia in lake and submerged plants community remediation at home and abroad.Main content include:The main exogenous pollution of Yilong lake is the Domestic sewage,industrial wastewater,agricultural non-point source pollution from the river.This paper make a analytic statistics on historical data and current situation.We can control the pollution before the water into lake to improve the quality of water supply through ecological technical measures which can remediate the water quality in the river into lake.Through monitoring of the relationship between water depth and transparency‘s change,we take water level control measures.We determine a reasonable amount of water supply cooperating with the submerged plants community remediation,we suggest that the amount of water supply keep above 60 million m3.But it‘s not appropriate to supply water too fast,we should give more conditions for plants in shoal area.For example,if we supply water in first year,we suggest not supplying much water in second year to give more adaptive time for lake ecosystem,in the third year we can supply water step by step based on the reality.Mud from the bottom of Yilong lake have rich submerged plants seeds bank,through combination of water level control,we can remediate submerged plants by activating the seeds bank.There are significant difference in water depth,water quality and plant distribution between east Yilong lake and West Yilong lake.So we take different strategy to remediate.East adopt the ecological management route in remediating pioneer species,West adopt the ecological remediation route in restoring the biodiversity.West lake lead east lake,finally restore the original ecology of the whole watershe.Yilong lake have rich sightseeing resource,we suggest that change economic development strategy,combining economic development with environment protection.Call all people to act,return a natural ecology Yilong lake.