气候变化对大兴安岭北部沼泽景观格局的影响
Impacts of climate changes on the landscape patterns of potential mire distributions in northern Great Khing’an mountains
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摘要: 大兴安岭北部地区由于在高纬、高海拔双重因素作用下,形成了独特的山地沼泽类型。首先使用Logistic回归模型分析了沼泽湿地与18种环境因子(11种地形因子和7种气候因子)的关系,结合CGCM3未来气候模型(加拿大气候模拟和分析中心推出的第三代全球气候耦合模型)预测未来分布,然后利用Fragstats软件计算景观格局的变化。所建模型具有很高的预测精度(ROC为0.96),预测结果表明:到2100年,SRESB1情景下,大兴安岭北部沼泽的潜在分布面积减少54.16%,南部相对平坦的丘陵和山间平原的沼泽大量消失;SRESA1B情景下,面积减少59.62%,南部林区的沼泽几乎全部消失;SRESA2情景下,面积减少73.51%,沼泽几乎完全退化到北部海拔较高处。另外,沼泽景观格局随气候变暖,平均斑块面积变小,形状指数减小,聚集度减少但幅度不大,这说明沼泽分布趋于破碎化,斑块的形状趋向于简单化,沼泽分布由边缘向中心收缩。Abstract: The mires in northern Great Khing'an mountains are particular with high latitudes and high altitudes.A Logistic regression model is developed to analyze the relationship between mire distributions and 18 eco-factors (including 11 topographic and 7 climate factors).The future potential distributions of mires are predicted under CGCM3,and the landscape changes are calculated by Fragstats software.The Logistic model has high prediction precision (ROC=0.96).The prediction results show that:by 2100,under the SRES B1,the potential mire area will decrease about 54.16%,and mires will disappear in the south of the flat hilly regions and intermontane plains; under the SRES A1B,the potential mire area will decrease about 59.62%,and mires in south forest regions will disappear; under the SRES A2,the potential mire area will decrease about 73.51%,and mires will be found only in the north area with higher elevations.In addition,the mean patch areas,landscape shape indexes and aggregation indexes will reduce,which means that the mire distribution will shrink from edges to centers and tend to be fragmented with simple patch shapes.