开垦60年东北三江平原典型产粮区生态脆弱性时空格局演变分析——以859农场为例

Temporal and spatial dynamics of ecological vulnerability in typical grain-producing area of Sanjiang plain in Northeast China during 60 years' reclamation

地处东北黑龙江省的三江平原是我国重要的产粮区,上世纪50年代以来经历了高强度的湿地开垦,改变了原有的景观格局和生态系统结构,使得生态脆弱性问题成为制约该区可持续发展及粮食生产安全的重要因素。文中以该区开垦程度较大的859农场为例,利用开垦60年(1950s^2013a)来8个时期的遥感影像解译的土地利用结果,从景观格局角度选取生态压力指标与结合土壤侵蚀敏感性指标构建生态脆弱性评价模型,对研究区生态脆弱性时空动态变化进行定量分析,分析其生态脆弱性时空变化规律。结果表明:1)开垦60年,景观格局发生巨大变化,草地、林地2种景观类型景观生态脆弱性变化明显。2)开垦60年,农场生态脆弱性显著增加。初期上升明显,自1980s后变化趋缓,新世纪以来,随着垦荒强度以及各种生态保护政策与农田管理措施的变化,农场生态脆弱性也随之出现了剧烈波动,总体有向好的趋势。3)研究区生态脆弱性变化方向与开垦方向相同,开垦30年后生态脆弱性较高区域呈现出增加的趋势,主要分布于位于林地-耕地-草地交界区域。研究结果说明:人类活动是影响东北典型产粮区生态脆弱性的关键因素。过度开垦对区域生态脆弱性有负面影响,而退耕退湿等政策能缓和区域生态脆弱性状况,保障区域可持续发展。

The Sanjiang Plain,located in the northeast of Heilongjiang Province,is an important grain-producing area of China.Since 1950 s,it has undergone high-intensity wetland reclamation,which changed the original landscape pattern and ecosystem structure,and made the ecological vulnerability being an important restraint to local sustainability and food production.In this research we built an ecological vulnerability model,which integrated the ecological stress index with respect to landscape change caused by human activity and ecological sensitivity index reflecting soil erodibility.Then,we selected 859 farmlands with a high degree of reclamation in this area as an example.Based on the interpretation results of remote sensing images for land use of eight different periods since 1950 s to 2013 a,temporal and spatial dynamics of ecological vulnerability as well as the impact from reclamation were analyzed.Results showed that,（1） Wetlands decreased drastically and cultivated land increased dramatically during 60 years of reclamation.Ecological vulnerability of grassland and woodland changed greatly.（2） During 60 years of reclamation,the ecological vulnerability of 859 farmlands dramatically increased.It showed a sharp upward trend at first,and a little increase after 1980 s.Since the 21 Century,along with the increase of reclamation intensity and the change of ecological protection policy,ecological vulnerability fluctuated heavily,but had a trend to decrease.（3） The spatial distribution of ecological vulnerability of 859 farmland showed that the vulnerability areas were expanding along the reclamation direction.And after 30 yrs’ reclamation,the most vulnerable areas increased and they were mainly distributed in the forest-arable land-grassland areas.According to our results,human activities were the main factor affecting dynamics of ecological vulnerability of typical grain-producing area of Sanjiang plain in Northeast China.And long-term reclamation had a negative effect on the ecological vulnerability,but the policy of reducing arable land and restore wetland had obvious effect on decreasing it.