The Evolution Of Swamp Landscape Patterns In Western Songnen Plain And Its Effect On Revegetation Potentiality

The characteristic of spatial-temporal evolution of landscape pattern and wetlands restoration are the hot spots that have been paid attention by geography and landscape ecology for a long time.Based on"3S"technology,the swamps in western Songnen Plain as the research object.The spatial-temporal differentiation rule of swamp landscape patterns in the western Songnen Plain in different periods was studied by using the grid analysis method,and the driving factors analysis were carried out.Based on Robert's model of wetlands revegetation potentiality,combined with analytic hierarchy process,the revegetation potentiality of marshs in western Songnen Plain was evaluated;linear regression analysis was used to study the effect of landscape pattern evolution on revegetation potentiality of swamps in western Songnen Plain in different periods,Provide reference for the protection and management of marshs in western Songnen Plain,the results is following:(1)From 1985 to 2015,the swamps area in the western Songnen Plain decreased first and then increased.The swamps area decreased by 684.75 km~2 in total,and the proportion of the largest patch to the landscape area decreased from 1.92%to 1.44%;the fragmentation and dispersivity of the marshs landscape gradually increased.The landscape shape underwent a complicated-simple-complex process.The aggregation index showed the tendency of inverted"V".From a spatial point of view,in 1985,the fragmentation degree and landscape shape of swamps landscapes in the western Songnen Plain gradually decreased from central to southeast,northeast,and northwest,and the degree of patch aggregation gradually increased from central to north and south.The stability of patch structure was strong in the midwest and weak in the east;after 2000,the patch density and landscape shape index in the swamps migrated to the east,and the stability of the patch structure in the central area was higher.The high value areas of maximum patch area ratio were mainly distributed in the western part of the study area;the evolution of swamp landscape patterns in the western Songnen Plain from1985 to 2015 was mainly affected by climatic factors,hydrological factors and human disturbances,among which the changes of human disturbance degree had great influence on it.From 1985 to 2015,the degree of human interference increased from 0.57%to 0.61%,showing an increasing trend year by year.(2)From 1985 to 2015,the revegetation potentiality of marshs in the western Songnen Plain generally showed a downward trend.In the previous period(1985-2000),the reduction rate of the revegetation potentiality of marshs in the study area was greater than that of the revegetation potentiality of swamps in the later period(2000-2015).From 1985 to 2015,the high value areas for revegetation potentiality in the study area have been maintained in the north,and the low value areas have remained in the southeast of the study area.The high value range in the north has continuously narrowed,and the low value range has continuously expanded,revegetation potentiality in and around the nature reserve more stable.From 1985to 2015,the revegetation potentiality of marshs in the western Songnen Plain was transformed from north to south,and its centroid experienced a process of“southwest-northeast-southeast”.The spatial agglomeration of revegetation potentiality in the southeast of the study area gradually increased.(3)The spatial distribution of revegetation potentiality of marshs in the western Songnen Plain between 1985 and 2015 was significantly related to the proportion of the largest patch to the landscape area and the aggregation index.The proportion of the largest patch to the landscape area in the swamps in the study area from 1985 to 2015 was significant to its revegetation potentiality.The effect was the largest,and the contribution to revegetation potentiality was 82.865%,99.107%,and 86.293%respectively in 1985,2000 and 2015.The revegetation potentiality of marshs in the study area in 1985 was also affected by the patch density,and its contribution to revegetation potentiality was 17.013%.In 2015,therevegetation potentiality of marshs in the study area was also affected by the aggregation index and the stability index of the patch structure.Their contribution rates to revegetation potentiality were 9.044%and 4.663%respectively.