土地利用类型变化对生态服务价值的影响

高速公路修建,通过改变沿线土地利用类型导致其生态服务功能发生变化。基于Costanza等人率先研究的全球陆地生态系统服务价值的分类与评估法,结合中国学者对土地利用类型单位面积的生态价值估算结果,评估了西汉高速户县—勉县段沿线土地利用类型生态服务价值及其变化。结果表明,高速公路修建占用的4种土地类型主要是农田、园地、林地和草地,面积分别是1 116.41,6.84,125.21,125.77hm2。由于绿化、恢复植被等措施,建成后的林、草地面积,分别增加了155.26和21.40 hm2。高速公路建成后,农田、园地的生态服务价值消失,同时林、草地面积的增加,使废物处理、气候调节功能价值增加量最大;增加幅度最大的是气候调节、栖息地和娱乐功能。耕地、园地面积消失,使食物供应、生物控制和传粉功能减少量最大。减少幅度最大的分别是生物控制、食物供应和传粉功能,分别为89.67%,72.51%和61.84%。总体上,公路建成后,土地总的生态功能价值较以前呈减少趋势,减少了3.72×105元/a,每1 km平均1 400元/a。高速公路给区域带来的巨大经济效益和社会效益,会远大于其对生态环境破坏所造成的土地利用类型生态服务价值的损失。

Effects of Different Land Use Types on Ecosystem Service Value

The construction of expressway results in the changes of the ecosystem service value via changing the land use types.Based on the classification and evaluation method of global land ecosystem service value first used by Costanza et al.(1997) as well as ecosystem service values of unit area of each land use type estimated by Chinese scholars,the changes in ecosystem service value of different land use types were evaluated after the construction of the Huxian-Mianxian section of Xi'an-Hanzhong expressway.During the construction,1116.4 hm² farmland,6.8 hm² orchard,1²5.² hm² woodland and 1²5.8 hm² grassland were used.However,after the construction,areas of the woodland and grassland were increased by 155.3 hm² and ²1.4hm²,respectively,due to vegetation restoration and landscaping.The ecological service values of climate adjustment,habitats,and recreation increased due to increases in woodland and grassland areas.The construction nullified the ecosystem service value of farmland and orchard,which reduced ecological service functions of biological control,food supply,and pollination by 90%,73%,and 6²%,respectively.In general,the overall ecosystem service value tended to decrease,about 1400 yuan per year per kilomemter after the construction of the expressway.However,the loss of ecosystem service value is expected to be far less than the economic and social benefits that the expressway can bring to the area.