The Influence Of Climate Change On Suitable Habitats Of Afforestation Tree Species Based On Niche Model

In recent years,the rapid progress of society,especial the quick development of industry has brought tremendous impacts on environment.As environment changes,climate also changes very drastically.Geographical distribution of species changes as the climate changes.Therefore,the study of suitable habitats of species is particularly important.Forest management planning is a very important part in forestry.Studying suitable habitats of forests has important theoretical and practical significance for the formulation of long-term forest management plan.As a forestry province,Hunan Province is rich in forest resources and its forest coverage rate reaches 59.57%.Pinus massoniana is an important timber species in Hunan Province.Also it is one of the main afforestation species.During the compilation of long-term forest management plan in Hunan Province,it has a great significance to study the suitable habitat distribution of Pinus massoniana under the influence of climate change for the implementation of the principle of matching site with trees and scientific afforestation.In this study,Pinus massoniana in Hunan Province was chosen as the research object.Use the elevation data,climate data and spatial distribution data of Pinus massoniana in Hunan Province to model the current distribution of Pinus massoniana.Use Bioclim model,Domain model,GARP(Genetic Algorithem For Rule-Set Prediction)model,MaxEnt model and Logistic model to modelling the distribution.Also,the spatial distribution of Pinus massoniana comes from forest resources continuous inventory updated data.Comparing the model accuracy to find the optimal model.Use this optimal model to predict the suitable distribution area of Pinus massoniana in 2050 and 2070.Analyse the changes of the prediction results by jackknife method.Comparing the prediction results,determine the main factors which affect the distribution with the results of jackknife method.Because of the variability of world climate,it's necessary to analyse the suitable habitats of Pinus massoniana in Hunan Province in several scenarios by using the data of the World Climate Database.Determine the appropriate distribution area of Pinus massoniana to provide a scientific basis for the selection of planning afforestation sites in long-term forest management.Research indicates that:(1)The calculation results of AUC values show that:the AUC values of Bioclim model,Domain model,GARP model,MaxEnt model and Logistic model are 0.816,0.831,0.819,0.872 and 0.805.All of the AUC values are greater than 0.8.It is indicated that each model can predict suitable habitats of Pinus massoniana in Hunan Province well.Among them,MaxEnt model has the highest precision,and Logistic model has the lowest prediction accuracy.According to the values of AUC,these models are ranked from high to low as MaxEnt,Domain,GARP,Bioclim,and Logistic.(2)MaxEnt model is the optimal model after analyzing.Use MaxEnt model to predict suitable habitats of Pinus massoniana in 2050 and 2070.The prediction results show that the suitable habitat,low suitable habitat and unsuitable habitat area of Pinus massoniana in HunanProvince of total area of the province are 27.6%,40.9% and 31.5% in 2050.Suitable habitats of Pinus massoniana are mainly distributed in the central and northwestern parts of Hunan Province.In 2070,suitable habitats,low suitable habitats and unsuitable habitats of Pinus massoniana in Hunan Province accounted for 18.1%,35.3% and 46.6% of the total area of the province.Suitable habitats are still mainly distributed in the central and northwestern parts of Hunan Province.(3)Comparing the area ratio of suitable habitats,low suitable habitats and unsuitable habitatsat in Hunan Province,it indicates that the area of the suitable habitats and low suitable habitats of Pinus massoniana in Hunan Province show a progressive decrease and unsuitable habitats show a progressive increase in 2070.The analyze of jackknife method shows: elevation,slope and precipitation in coldest season account for a large contribution rate.Precipitation in coldest season is the main climate factors affecting the geographical distribution of Pinus massoniana.(4)Scenario analysis shows that in the scenario of temperature increased and precipitation constanted(A scenario),suitable distribution area of Pinus massoniana in Hunan Province has a tendency expanding to eastward.In the scenario which the precipitation increases and the temperature does not change(B scenario),suitable distribution area of Pinus massoniana in Hunan Province keep constant in the central and northwestern parts while the south and northeast part of Hunan Province are shifted to the north.In the scenario which temperature and precipitation increased(C scenario),the suitable distribution area of Pinus massoniana in Hunan Province has a tendency to shift to the north.(5)The overlay analysis of each scenarios suitable habitat shows: The best afforestation sites for Pinus massoniana are Zhangjiajie City,Xiangxi,Huaihua City,north of Shaoyang City,Southwestern of Yueyang City in the long-term forest management planning in Hunan Province from 2016 to 2050.