北京市消耗食物生态足迹距离

The ecological footprint distance of food consumed in Beijing

以北京市消耗食物生态足迹的距离为研究核心。结果表明2008年至2012年,北京的生态足迹距离、人均生态足迹和生态足迹总里程总体呈现逐年增长趋势:生态足迹距离增大到676.75 km,增长19.3%;人均生态足迹距离增加到18.42万km,增长54%;生态足迹总里程增加了1倍强,达到56亿t km。北京市的食物生态足迹距离不断扩大,并涵盖了全国大部分地区,北京城市化的生态成本上升。所消耗各类食物的生态足迹距离从大到小分别为水果类、蔬菜或粮油类、肉蛋类和水产类。蔬菜类和水果类的生态足迹距离存在明显的季节波动,且冬春季节远高于夏秋季节。从转移生态承载力来源地的视角,直线距离越远、占据市场份额越大的地区,对北京市消耗食物生态足迹距离的贡献率越高。

In this paper, we analyzed the size of the ecological footprint of food consumed in Beijing. Population data and information on resident food consumption were collected from the ＂Beijing Statistical Yearbook＂ and ＂Chinese Migrants Development Report＂ from 2008 to 2012. An additional market investigation was carried out.The food-related ecological footprint distance increased 19.3% （to 676.75 km）, from 2008 to 2012, reflecting a trend of expanding scope of dependency for ecological goods used in Beijing. The ecological footprint distance per capita enlarged nearly 54% （to 184.2 km） , implying a trend of rapid increase in the cost of living in Beijing. There was an overall increasing trend in the total size of the total mileage of ecological footprint of Beijing, the ecological footprint distance and the ecological footprint distance per capita. The total mileage of the ecological footprint increased more than 200% （ to 5.6 thousand million t km）. The growth rate of total mileage of the ecological footprint was faster than the growth rate of the population. This might show loss of the benefits of scale of the expanding city, and the declining efficiency in configuration of ecological resources. Although the scope of Beijing＇s ecological footprint covered most regions of China, from the aspect of their market share, it was still too concentrated for Beijing to maintain a stable ecosystem in the metropolitan area. According to the results of seasonal analysis of five consecutive years, it could be inferred that the Ecological Footprint Distance of vegetables and fruit varied obviously among different seasons, usually higher in winter and spring. Yet the ecological footprint distance across seasons was relatively steady for grain and oils, meat and eggs and aquatic products. While taking into account the stability of the path of ecosystem material flows, the material flows of vegetables and fruit are more fragile than of other kinds.The largest group according to Beijing＇s ecological footprint distance was fruit, the second was vegetables or grain and edible oil （in different years）, the third was meat and eggs, and the smallest group was aquatic products. The biggest contributors to Beijing＇s ecological footprint distance were vegetable and fruit. The development of a base of supply for vegetables and fruit in surrounding areas would effectively decrease Beijing＇s ecological footprint distance. The average ecological footprint distance of vegetables increased from 475.23 km to 727.13 km from 2008 to 2012, with an obviously ascending trend. The average ecological footprint distance of fruit increased from 905.55 km to 1073.55 km from 2008 to 2010, and then decreased to 886.66 km in 2012. The average ecological footprint distance of fruit was much larger than for the other four kinds of food resources. The ecological footprint distance of each kind of food resource had a close relationship with their spatial distance and market share of their source-regions ： the longer the spatial distance, and the larger the market share, the higher the value of the ecological footprint distance. The ecological footprint distance was established based on the concept of ecological footprint, but reflects a different aspect of human impacts on natural ecosystems. Ecological footprint is an area indicator while the ecological footprint distance quantifies distance. The ecological footprint demonstrates the scope of natural space influenced by humans, while the ecological footprint distance describe the distance to which ecological dependence extends from a certain object, such as a city. The indicator of ecological footprint distance is an important complement to the theoretical system of ecological footprint and bio-capacity.