Investigation And Quality Evaluation Of River-Bar Wetland Habitat In Xinjin Section Of Middle Minjiang River

River habitat health is related to watershed ecological environment management,which is restricted by its own morphological characteristics,hydrological processes and human activities.The Xinjin Section in the middle reaches of the Minjiang River is a wandering river.Influenced by perennial scouring,transport and deposition,it forms river-sandbar complex geomorphic features and eventually develops into river-bar wetland.As a kind of compound wetland,its habitat structure has the characteristics of nature,rarity and diversity,which can maintain and enhance the diversity of river habitat,and has high ecological value.However,as Xinjin is in the accelerated stage of urbanization,it has a great impact on the protection and management of river-bar wetland habitat.In view of this,this study combined with relevant research literature and domestic and foreign practical experience to build a set of simple,convenient and efficient wetland habitat evaluation system,which is composed of wetland habitat investigation,index system construction and evaluation methods.Based on the comprehensive research methods of habitat quality evaluation of river wetlands at home and abroad,combined with the characteristics of river-bar wetland habitat in Xinjin section of middle Minjiang River,a river habitat evaluation system suitable for river-bar wetland at micro scale was formed;At the same time,this study also established a reference system for habitat quality classification of river-bar wetlands,which can provide a reference for future protection,restoration and management of similar river-bar wetlands.The results showed that among the 10 habitat quality indicators,the quality of four indicators,namely,the vegetation structure of the river flat,the water volume of the river channel,the longitudinal continuity of the river channel and the land use type of the river bank,was "good",accounting for 40%.There was no need for habitat restoration,but only for key protection.The quality of the six indexes of river sandbank characteristics,river bed sediment,riparian vegetation structure,special habitat,river channel flow pattern and human activities was "poor",which needs to be repaired or managed.And according to the need to repair the habitat analysis,put forward the corresponding habitat restoration methods.In the10 sample sections,2 of them had "excellent" wetland habitat quality,accounting for 20%.There were 2 sites with "good" habitat quality,accounting for 20%.There were 2 sites with "average" habitat quality,accounting for 20%.There were 2 "poor" points,accounting for20%;There were 2 points of "difference",accounting for 20%.This grade is used as a reference system to provide reference value for the future evaluation of river-bar wetland habitat in the middle reaches of the Minjiang River.From the point of view of the river-bar wetland section of the river,the tributaries of the Xihe River,the Jinma River and the main flow of the Minjiang River show different characteristics.There were 4 sample sections in the tributaries of Xihe River,one of which was "excellent",accounting for 25%.2 "poor",accounting for 50%;1 "difference",accounting for 25%.There were 3 sections in Jinma River tributaries,of which 2 were of "good" grade,accounting for 66.6%.1 "average" rating,accounting for 33.3%.There were three sample sections in the main flow of Minjiang River,among which there was one "excellent" section,accounting for 33.3%."General" 1,accounting for 33.3%;"Poor" 1,accounting for 33.3%.Finally,according to the evaluation results,the restoration of the "poor" river reach was studied,and the restoration suggestions for the indicators of "poor" habitat quality were put forward.