| Positive natural regeneration is the foundation of the sustainable development of the forest ecosystem.Research the emerging and survival dynamics of Tianshan spruce(Picea schrenkiana var.tianschanica)seedling,and the interrelation between survival numbers,functional traits,and microhabitat factors helps to understand the changing law of life and death dynamics in the seedling staged,and deepen the scientific comprehension of the screening function of environmental filter in the settlement stage of Tianshan spruce seedling.In this paper,the 1-year-old Tianshan spruce seedling of natural regeneration was taken as the research object.Based on the survey data based on in situ monitoring and typical plots,the emerging process and death dynamics of seedling under different microhabitat types were analyzed,as well as the death dynamics of seedling under different emerging periods,and the variation of seedling survival numbers and functional traits were explained by microhabitat factors.The main findings are as follows:Based on ground cover and soil characteristics,the microhabitat of one-year-old spruce seedling can be divided into three types: moss type,herb type,and litter type.In the moss-type microhabitat,the moss coverage thickness was significantly higher than the other two(P<0.05),and the slope index and humus thickness were significantly lower than the other two(P<0.05);In the herbaceous microhabitat,herbaceous coverage,thick root coil layer,and soil compactness were significantly higher than those of the other two(P<0.05);The litter coverage thickness of litter type microhabitat was significantly higher than that of the other two(P<0.05),and the soil water content was significantly lower than that of herbaceous microhabitat(P<0.05).The seed germination and seedling emergence of Tianshan Spruce followed the Weibull type time-release model.The emergence process of the seedling can be divided into three stages:initial stage,peak s,tage and final stage.In the initial stage,the average cumulative number of moss type,herb typ,e and litter type microhabitats were 1.98,0.92 and 0.94 plants respectively,and the duration was 21,12 and 10 days respectively;In the peak period,the average cumulative number of the three microhabitats was 14.04,8.23 and 10.43 plants respectively,and the duration was 26,29 and 34 days respectively;The three microhabitats entered the end stage on the 47 th,43rd and 44 th days,respectively.The main meteorological factors related to the number of seedling are rainfall days,minimum soil temperature,rainfall and average soil temperature.The survival time of seedling in mossy microhabitats was significantly higher than that of the other two types(P<0.05).The risk rates of seedling death at the peak and end of emergence were 116.72% and 205.41% higher than those at the initial stage(P<0.01).The mortality risk of seedling in mossy microhabitats was significantly lower than that in herbaceous microhabitats by 31.66%(P<0.05).The most important meteorological factors related to the number of seedling deaths are the minimum temperature,average temperature,minimum ground temperature,and rainfall.The microhabitat factors that can significantly affect the survival quantity and functional traits of 1-year-old natural regeneration seedling of Tianshan picea include moss thickness,litter thickness,herb coverage,root mat thickness,tree neighbor effect,altitude and slope position.They can explain 47.43% of the variation of survival quantity and functional traits of 1-yearold natural regeneration seedling of Tianshan spruce. |
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