青藏高原气候变化对农牧民开垦的影响

自1980年代后期以来,青藏高原持续变暖趋势明显,且增温幅度高于我国其他地区。基于遥感数据和种植适宜性模型的一些研究表明,该地区足够的农业热量资源增加了适宜耕种土地的面积,为农牧民的开垦行为创造了有利的条件。然而,对农牧民是否开垦以及开垦原因的实证研究,以及农牧民如何平衡气候变化带来的开垦机遇、风险和人口压力,仍然缺少认识。以青藏高原的3个典型产粮区域("一江两河"地区、河湟谷地、壤塘县)为研究区,利用605户农户家庭调研数据,分析了影响农牧民开垦行为的影响因素。计量结果表明,农牧民感知冬季持续时间的整体变化趋势、家庭总人口、抚养比与农牧民开垦行为呈显著正相关关系;农牧民感知降水的整体变化趋势、人均打工年收入、户主受教育水平、是否借贷、居住地距集镇距离与农牧民开垦行为呈显著负相关关系。随着城镇化的不断加快,农牧民对非农工作的认可度越来越高,加之政府的管制,使得开垦现象并不普遍。由于农牧民的开垦对青藏高原的生态环境极有可能造成不可逆的负面影响,应该提供更多的非农就业机会,促进农业集约化,加强监管,以降低开垦的可能性。

Impacts of climate change on the reclamation of farmers and herdsmen in the Tibetan Plateau

Since the late 1980s, the Tibetan Plateau has continued to warm, and this trend is higher than in other parts of China. Some studies based on remote sensing data and planting suitability models showed that sufficient agricultural heat resources in the region increased the area suitable for cultivated land and created favorable conditions for farming and herdsmen''s reclamation. However, there has been a lack of empirical research on whether and why farmers and herdsmen reclaim these lands and how they balance the opportunities, risks, and population pressures brought by climate change. In this paper, three typical grain producing regions of the Tibetan Plateau (the YNL river region, He Huang Valley, and Zamtang county) were chosen as the research areas, and 605 households'' survey data were used to analyze the influencing factors for farmers'' and herdsmen''s reclamation behavior. The results showed that there was a significant positive correlation between farmers'' perception of winter duration, total household population, dependency ratio and farmers'' reclamation behavior; there was a significant positive correlation between farmers'' perception of precipitation, annual wage per capita, education level of household heads, whether to borrow or not, and the distance from residence to town and farmers'' reclamation behavior. With the acceleration of urbanization, the recognition of farmers and herdsmen towards non-agricultural work is increasing. With the government''s control, reclamation is not widespread. Because reclamation is likely to cause irreversible negative impacts on the ecological environment of the Tibetan Plateau, we should provide more non-agricultural employment opportunities, promote agricultural intensification, and strengthen supervision, to reduce the possibility of reclamation.