关键词: 兴安落叶松林, MAXENT, 空间格局, 气候变化

Abstract: Climate change directly affects the geographical distribution of vegetation. Larix gmelinii forest is mainly distributed in Greater Khingan Range and Xiao Hinggan Range in Northeast China. It is located in the southern edge of the boreal forest, with high sensitivity to changes in water and heat conditions. In this study, MAXENT model was used to simulate the spatial distribution of L. gmelinii forest in Northeast China, the potential spatial distribution of different representative concentration paths (RCP2.6, RCP4.5 and RCP8.5) in 2050s and 2070s, and the responses of suitable areas of L. gmelinii forest to climate change. Results showed that environmental factors that mainly contribute to the geographical distribution of L. gmelinii forest included annual temperature range, aspect, seasonal temperature change, mean temperature in the driest season, and minimum temperature in the coldest month. The cumulative contribution rate of those five factors reached 83.80%. Part of L. gmelinii forests in Northeast China are mainly distributed in Greater Khingan Range of Heilongjiang Province and the northern part of Hulunbeier City in Inner Mongolia, which is dominated by the state-owned forest in Greater Khingan Range. The other part is dominated by the state-owned forest in the central and northern part of Xiao Hinggan Range in Heihe City and Yichun City in Heilongjiang Province. Under all kinds of future climate scenarios, the newly increased suitable area of L. gmelinii forest would be less in 2050 and 2070. The suitable area of the east side of Greater Khingan Range and the Xiao Hinggan Range would show stronger decrease. The loss rate of the suitable area would be 15.06%-38.87%, concentrated in Heihe City and Yichun City of Heilongjiang Province. The response of L. gmeliniiforest to climate change was analyzed using the multi-classification Logistic regression method. Results showed that the decrease of seasonal variation of temperature and precipitation, the increase of precipitation in the driest season, and the increase of the highest temperature in the warmest month were the main reasons accounting for the reduction of suitable area of L. gmelinii forest.

Key words: Larix gmelinii forest, MAXENT, spatial pattern, climate change.