| Wetland is an animal and plant ecosystem that depends on water.This ecosystem plays an important role in resisting flood disaster,regulating surface runoff,controlling river pollution,improving local climate,maintaining biodiversity and beautifying regional environment.Since the 1970s,landscape ecology has been gradually introduced into wetland research,and the dynamic change of wetland landscape pattern has been a hot topic in wetland ecology research.In this context,it is of great significance to strengthen the analysis and research of wetland land type change for monitoring,analysis and management of wetland ecological environment change.Most area of Baiyangdian are under the jurisdiction of Hebei Xiong'an New District,and have become an important area for the ecological development of Xiong'an New District.It is rich in natural resources and diverse in landscape types,and has important ecological research value.It is of great significance for the future planning of xiong'an Baiyangdian Lake,the establishment of ecological protection zone and the restoration of ecological environment to carry out the research on the land use type and landscape pattern change of Baiyangdian Lake,reveal the law of change,the factors causing change and the characteristics of change in different regions.This paper selects Landsat images from 1 999,2005,2011 and 2017,collects relevant data and conducts on-the-spot investigation.Referring to the wetland classification system of the wetland convention,the landscape of Baiyangdian Lake is divided into seven types:natural water body,artificial water body,aquatic plant,cultivated land,forest land,construction land and bare land,from landscape pattern change,landscape type transfer and Three dimensions of landscape pattern index were used to analyze the dynamic change of landscape pattern in Baiyangdian Lake.The driving factors of the change were studied by qualitative analysis.The optimization strategy of ecological pattern was put forward by the principle of patch corridor basement,and the ecological function zoning planning was carried out by combining ecological sensitivity analysis and landscape ecology.The results show that:(1)In terms of the overall landscape dynamics,the wetland area of Baiyangdian Lake has been degraded continuously in the past 18 years,with a decrease of 5019.66hm2 or 19.35%;the largest decline of aquatic plants,with a decrease of 7044.1Ohm2 or 21.68%;the area of cultivated land and bare land increased first and then decreased,with an increase of 1082.25hm2 and 839.43hm2 in the past 18 years,respectively The area of construction land and forest land continued to increase,with an increase of 1007.37hm2 and 2090.61hm2.(2)During 1999-2005,the landscape transfer of Baiyangdian Wetland was dominated by the outflow of natural wetland landscape type,with a large amount of area flowing into cultivated land and artificial water body,and the backflow began after 2005;after 2011,cultivated land began to flow out,and artificial water body began to flow into natural wetland type;in the early stage,due to the interference of climate and human beings,a large amount of area flowed into bare land,In the later period,with the improvement of land use efficiency and wetland restoration,the area of bare land began to flow out;in the three periods,the cultivated land area flowed into the construction land and forest land.(3)Landscape level:the number of patches(NP)increased from 11722 in 1999 to 16720 in 2017,while the average patch area decreased,and the fragmentation degree of Baiyangdian landscape increased;the area weighted average shape index increased from 18.29 to 20.29;the maximum patch index decreased significantly,from 53.89 to 14.08;the aggregation index decreased from 54.04 to 34.63;Shannon diversity The Shannon evenness index increased from 0.64 to 0.90.On the type level:the fragmentation degree of natural water body and aquatic plants increases,the landscape dominance degree decreases,and the landscape pattern becomes more and more complex;the fragmentation degree of cultivated land first decreases and then increases,and the dominance degree first increases and then decreases;the patch density and the maximum patch index of construction land and forest land gradually increase,the fragmentation degree increases,and the landscape dominance degree all increases.(4)The evolution of Baiyangdian landscape pattern is divided into human factors and natural factors:the precipitation in the lake area caused by climate change is much lower than the evaporation;the decline in precipitation in the watershed and the decrease of the inflow water caused by the construction of dams;cities Expansion and increase in agricultural land have led to increased water consumption in cities and agriculture;returning farmland to lake,diversion of water to Jidian,and environmental improvement of tourist areas are the main reasons for the restoration of wetland area in Baiyangdian in the later period.(5)Based on the analysis of landscape pattern and driving factors,the article proposes a strategy for landscape pattern optimization:patch structure adjustment starts from maintaining key landscape patches,rational patch layout,and enriching patch diversity;ecological corridor construction The main aspects are divided into two aspects:rational design of different types of embankment corridors and rational grooming of river corridors;the optimization of basement focuses on protecting the integrity of farmland basement and wetland basement,improving ecology,and avoiding human interference.(6)By analyzing the ecological sensitivity of Baiyangdian,it is found that the area of extremely sensitive area of Baiyangdian is 7308.81hm2,the area of both high and moderate sensitive areas are 6382.35hm2 and 6225.12hm2,respectively,and the area of light sensitive and insensitive areas They are 5251.77hm2 and 6683.19 hm2,respectively.The area distribution ratio of each sensitivity category is relatively balanced,but the spatial distribution of sensitivity intervals of each level is relatively concentrated.Combining the analysis of the landscape pattern changes and driving factors of Baiyangdian Wetland,and based on the analysis of the characteristics of landscape resources,patterns and functions,this paper divides Baiyangdian Wetland into ecological control zone,wetland restoration zone,ecological buffer zone,tourism activity zone,agricultural control zone,village and town There are 6 ecological function zones in the development zone,and the functional characteristics and overall planning control measures of each zone are clarified,and planning strategies for water quality restoration and protection and vegetation landscape improvement are proposed. |
PDF Full Text Request