Remote Sensing Based Assessment Of The Habitat Suitability For Waterfowls In The Western Songnen Plain, China

The western Songnen plain is one of the most important waterfowl habitats and migratory corridors, however, with a variety of ecological system ecosystem destruction, loss and degradation of wetland or grassland resources, which leading to an obvious decrease in waterfowl species and quantity. For the specific management and protection of waterfowl habitat, and maintenance of regional ecological security and biodiversity, it is more and more necessary to analyze the spatial and temporal variations of western Songnen plain wetland, investigate spatial pattern of suitability for waterfowl habitat, and assess the degree of suitability for waterfowl habitat. According to the present wetland situation in western Songnen plain, on the the basis of Landsat remote sensing image data in 1990 and 2015, combined with the field measured data, accurate extraction from the western Songnen plain wetland land use data was implemented. The space analysis was used to describe the present situation and transformation in the five typical wetland reserve (Zhalong nature reserve, Momoge nature reserve, Chagan lake nature reserve, Xianghai nature reserve, and Dabusu nature reserve) in the recent 25 years. Remote sensing and GIS spatial analysis method was synthetically performed to select suitable evaluation factors and build the evaluation criteria. Hierarchical analysis method was used to calculate the weight coefficient of each evaluation factor, remote sensing assessment of waterfowl habitat suitability and variation analysis in waterfowl habitat suitability in the recent 25years was implemented using HSI evaluation model in the study area. The main conclusions are as follows:(1) On the basis of Landsat remote sensing data, object-oriented classification method and artificial visual interpretation, the land cover is divided into 7 types:forest land, wetland, farmland, grassland, water body, bare land and artificial surface, the classification of land cover in western Songnen plain in precision test is 89.28%, which suggests it meets criteria of the study. The present situation of land cover in western Songnen plain in statistical analysis suggests that:the main types of land cover are farmland and grassland, followed by wetland, two of the least land cover types are bare land and artificial surface. In the spatial distribution analysis, it shows that wetland is relatively scarce in the southern area, especially in the remote areas far away from the rivers and lakes, and wetland is relatively intensive in the area along water areas such as rivers and lakes, mainly located in Zhalong nature reserve in the north of the study area.(2) Overall, the loss of wetland is relatively serious in western Songnen plain from 1990 to 2015, the wetland mainly transfer into arable land and grassland, others transfers into water body, which suggests that human activities take a great effect on the spatial pattern of wetland in study area. Additionally, some of other land use types transfer into wetland in the meantime, however, the area switching-in is smaller than switching-out. In the 5 typical nature reserve, the area of wetland in Momoge and Xianghai is drastically decreased, the loss of wetland is relatively serious; the area of wetland increased by 54% in Chagan lake nature reserve in the recent 25 years, since the baseline area of the area is very small, in general the increase is insignificant in Chagan lake nature reserve; besides, the wetland area in the Zhalong nature reserve and Dabusu nature reserve is also increased, while the increase is also insignificant.(3) The rate of best suitability for waterfowl habitat is about 12.72% in western Songnen plain, most of the area are flat, water sufficient and sparse population such as marshes and flood land, which is the best place to waterfowl concealment, foraging and reproduction; the area of general and good suitability for waterfowl habitat are widely distributed, which accounted for about 64% of the total area of the study area; the area of poor and inappropriate suitability for waterfowl habitat are 2.38×106 km2, which accounted for about 23.48% of the total area of the study area, and the stability of ecological system are poor, which are very difficult for waterfowl habitat in these areas, especially in urban areas, which is almost entirely not for waterfowl breeding and habitat. After comprehensive analysis of waterfowl habitat suitability conditions is done in five typical nature reserve, we find that compared with other areas, the rate of best suitability for waterfowl habitat area is relatively high in the most nature reserves except for Daubsu nature reserve, and the rate of poor and extremely poor suitability for waterfowl habitat are relatively low.(4) The areas of best and poor suitability for waterfowl habitat is decreased by 32.58×104 km2 and 21.00×104 km2 respectively, the area of good, general and extremely poor suitability for waterfowl habitat are increased, on the whole, the suitability for waterfowl habitat in western Songnen plain is worse than before from 1990 to 2015. In the analysis of 5 typical wetland reserves, we find that the suitability for waterfowl habitat in Zhalong nature reserve is improving from 1990 to 2015, the area of best suitability for waterfowl habitat is increased by 1.18×104 km2 in Momoge nature reserve, at the same time, the areas of general and good suitability for waterfowl habitat is decreased, the area of poor suitability for waterfowl habitat has a huge increment, the change in area of extremely poor suitability for waterfowl habitat is insignificant. The area of best suitability for waterfowl habitat has a huge increment in Xianghai nature reserve, the areas of extremely poor, poor and general suitability for waterfowl habitat is decreased, especially in poor suitability area from 1990 to 2015. The area of best suitability for waterfowl habitat is slightly decreased in Dabusu nature reserve, the areas of extremely poor suitability for waterfowl habitat has a certain degree of decrease, the areas of other suitability for waterfowl habitat has a certain degree of increase, especially in general and good suitability from 1990 to 2015;The area of good and best suitability for waterfowl habitat are significantly increased in Chaganhu nature reserve, the areas of extremely poor suitability for waterfowl habitat has a certain degree of increase, while the areas of poor and general suitability for waterfowl habitat are significantly decreased, in general the suitability for waterfowl habitat has a certain degree of increase from 1990 to 2015.