| The paper is a systematic analysis on population spatio-temporal dynamics and overwintering habitat characteristics of Aix galericulata in Shiqian Mandarin Duck Lake National Wetland Park,Guizhou Province.It is also a study on population dynamics and habitat selection of A.galericulata in southwest China where both overwintering and breeding exist.It could accumulate basic data for study of the relationship between waterfowl and wetland environment,and is of great significance for protection and management of A.galericulata and its wetland ecological environment.From October 2017 to March 2019,population quantity and distribution of A.galericulata were investigated by method of line and point,with Reservoir as a key research area;By using quadrat method and target animal method,these were analyzed on related factors of affecting overwintering habitat selection and response of human activity disturbances.Results are as follows:(1)Population dynamics and sex ratio characteristics of A.galericulata.Mandarin ducks migrate to the South and move from periphery of Mandarin Duck Lake to Reservoir in November;From December to February the following year,mandarin ducks were distributed in Reservoir,especially in extremely cold and low temperature weather,with quantity reaching the highest peak and stabilizing at more than 800;In March,mandarin ducks scattere and part of population migrate to the north;From April to October,they are paired distribution in Reservoir and around suitable river habitats for breeding,and quantity is stable at more than 400.Number of adult males is slightly higher than that of adult females during breeding and overwintering.(2)Distribution characteristics of A.galericulata population.Mandarin Duck Lake Reservoir is cluster core area of A.galericulata,and population density is significant seasonal differences in each small area of Reservoir.Breeding population of leech ditch is the highest,reaching 21±3/hm~2;overwintering population of Xiaohe is the highest,reaching 42±2/hm~2;However,annual population density is the lowest in Liangcha River and footpath waters,almost 0.(3)Characteristics of overwintering habitat selection of A.galericulata on wetland landscape types.Wetland landscape types of Mandarin Duck Lake are composed of a reservoir,rivers,woodlands,farmlands,barren grasslands,roads,villagers'houses,hydropower buildings,land for science and education,and park green space;But mandarin ducks choose a reservoir as their main overwintering habitat and rely on forest land as the most important hidden conditions,with activity scopes involving sparse woodland or barren land and farmland,always avoiding habitats disturbed by traffic roads,rural residences,hydropower station buildings and human activities.(4)Influencing factors of overwintering habitat selection of A.galericulata.Overwintering habitat selection is influenced by multiple habitat factors.Among them,there is a significant positive correlation with surface area of open water,width and depth of water,and distance between residential land,roads and other human disturbance sources.At the same time,food and hidden conditions are also key factors to determine whether the area is a suitable habitat for A.galericulata.(5)Effects of human disturbance on distribution and activities of A.galericulata.Negative effect of frequency and distance of human interference were very significant on population density of A.galericulata.In waters without human disturbance,population density could reach 41±3/hm~2 to 47±12/hm~2;However,population density was almost zero in waters where frequency of people entering and leaving being as high as 7±3 times per day.When being long-term frequency human disturbance,mandarin ducks will be forced to abandon the habitat.When distance of man-made interference exceeds 203±17m,mandarin ducks will be almost unaffected.But frightened flying distance of A.galericulata disturbed by human rowing is 69+11m. |
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