东北地区陆地生态系统生产力及其人口承载力分析

 日益增长的人口及其生存环境问题已经成为人类社会生存与可持续发展的关键，亦是区域生态承载力的重要指标。生态系统生产力及其人口承 载力研究不仅可以弄清某一区域所能承载的最大人口数量，而且能为农业生态系统的宏观调控和长远发展规划提供依据。东北老工业基地地处 地球环境变化速率最大的东亚季风区，以气候变暖为标志的全球变化必将影响东北地区生态承载力，进而影响该地区的人口承载力。该研究基 于10 km×10 km 分辨率的东北地区1980～2002年共23年的气象资料，结合植物生理生态特点和水热平衡关系建立的自然植被净第一性生产力模 型和农业生产力模型，借助于地理信息系统软件，分析了东北地区4类生态系统类型：森林、农田、草地和湿地的生产力及其动态，指出东北地 区近23年来年均气温呈显著上升趋势、年降水总体上呈减少趋势。23年来东北地区植被年均总生产力为3.52×10¹¹ kg DM&;#8226;a^－1，其中森林、农 田、草地和湿地的年均总生产力分别为1.53×10¹¹、4.55×10¹⁰、1.07×10¹¹和4.63×10¹⁰ kg DM&;#8226;a^－1，森林、农田、草地和湿地的平均生产 力为5.73×10³、1.84×10³、5.64×10³和5.55×10³ kg DM&;#8226;hm^-2&;#8226;a^－1。在此基础上，以第一性生产-第二性生产之间的生态适应性和能量-物 质流平衡(在食物链上传递机制)为主线，通过对第一性生产力在人类直接消费与第二性生产之间以及各畜群(猪、肉牛羊、禽、奶牛和水产品( 鱼))之间的分配 ，估算了1980～2002年东北地区在宽裕型、小康型与富裕型3种消费水平下，不输出商品粮和每年向国家提供350×10⁸ kg商品 粮条件下的年均总人口承载力分别为2.61×10⁸、2. 15×10⁸和1.77×10⁸；和1.70×10⁸、1.40×10⁸和1.15×10⁸。因此，要确保东北地区每年 向国家提供350×10⁸ kg的商品粮，且在未来东北地区的生活水平要达到富裕型水平，必须控制人口数量。在此基础上，根据2020、2050、2070 和2100年的气候预估资料，预测了2020、2050、2070和2100 年东北地区在宽裕型、小康型和富裕型3种消费水平下的人口承载力分别为2.73× 10⁸、2. 25×10⁸和1.85×10⁸；2.88×10⁸、2.38×10⁸和1.95×10⁸；3.03×10⁸、2.49×10⁸和2.05×10⁸；以及 3.09×10⁸、2.55×10⁸和2.09 ×10⁸。该研究可为东北地区及各省的生态建设与土地资源可持续利用提供参考。

TERRESTRIAL ECOSYSTEM PRODUCTIVITY AND CARRYING CAPACITY IN NORTHEAST CHINA

Aims Rapidly growing population and environmental issues have been key problems for the living and sustainable development of humans. In order to provide policy-makers with a theoretical reference, it is urgent to know how terrestrial ecosystem productivity and its carrying capacity in Northeast China will respond to future climatic change. My objective was to simulate net primary productivity (NPP) of terrestrial ecosystems in Northeast China and their carrying capacities, as well as their responses to climatic change. Methods Values of NPP of the different terrestrial ecosystems were simulated by a natural vegetation NPP model (Zhou &; Zhang, 1995) and an agricultural NPP model (Zheng et al., 1997), in terms of land use (forest, agriculture, grassland and wetland) data with a spatial resolution of 10 km×10 km and daily meteorological data from 1980 to 2002 as well as the projected climatic scenarios for 2020, 2050, 2070 and 2100. Ecosystem carrying capacities were given by the carrying capacity model (Cao, 1993) and NPP of agricultural, grassland and wetland ecosystems.  Important findings Mean annual temperature increased, and annual precipitation decreased in Northeast China from 1980 to 2002. Total mean annual terrestrial ecosystem productivity during these 23 years was 3.52×10¹¹ kg DM&;#8226;a^－1. Total mean annual terrestrial ecosystem productivities for forest, agriculture, grassland and wetland ecosystems were 1.53×10¹¹, 4.55×10¹⁰, 1.07×10¹¹ and 4.63×10¹⁰ kg DM&;#8226;a^－1 , respectively. Mean annual terrestrial ecosystem productivities for forest, agriculture, grassland and wetland ecosystems were 5.73×10³, 1.84×10³, 5.64×10³ and 5.55×10³ kg DM&;#8226;hm^-2&;#8226;a^－1. Total mean annual carrying capacities from 1980 to 2002 were 2.61×10⁸, 2.15×10⁸ and 1.77×10⁸ for well-off, comparatively well-off and surplus consumption levels, respectively. When 350×10⁸ kg commercial grain export from Northeast China was considered, total mean annual carrying capacities from 1980 to 2002 were 1.70×10⁸, 1.40×10⁸ and 1.15×10⁸ for the above three consumption levels, respectively. The population of Northeast China is about 1.07×10⁸ at present. It implied that the population in Northeast China should be controlled in the future, in order to ensure the surplus consumption level and 350× 10⁸ kg commercial grain export. Simulated total mean annual carrying capacities of Northeast China in 2020, 2050, 2070 and 2100 were 2.73×10⁸, 2.25×10⁸ and 1.85×10⁸；2. 88×10⁸, 2.38×10⁸ and 1.95×10⁸; 3.03×10⁸, 2.49×10⁸ and 2.05×10⁸; and 3.09×10⁸ , 2.55×10⁸ and 2. 09×10⁸ for the three consumption levels, respectively, in terms of the climatic scenarios for the future. This study provides fundamental information for land resources and social sustainable development.