Abstract: Climate change is one of the most serious challenges to human in the 21st century, which exacerbates the vulnerability of many countries and regions, especially for the agricultural population who relies on natural resources for their livelihoods. Clarifying the impacts of climate change on farmers’ livelihood vulnerability is of great significance for making effective adaptive strategy and strengthening the farmers’ adaptability and mitigating livelihood vulnerability to climate change. This paper takes Gannan Plateau, a representative ecologically vulnerable alpine region, as the study area, and establishes an index system for evaluating farmer households’ livelihood vulnerability to climate change. Based on 539 questionnaires of farmer households, we analyzed the impacts of climate change on farmers’ livelihood vulnerability in Gannan Plateau and the key factors affecting farmers’ livelihood vulnerability by using the multivariable linear regression model. The results show that: (1) The impacts of climate change differ with different types of households in Gannan Plateau, of which, the vulnerability of households with young householders is the strongest, and the vulnerability of households with middleaged householders is the least. The vulnerability of farmers’ livelihood to climate change tends to decrease from the low income households to the high income households, from the households with low education level to the households with high education level, from the households with less than 10% of their income from nonfarming to the households with more than 90% of their income from nonfarming, but to increase from the households with low dependency ratio to the households with high dependency ratio; (2) The impacts of climate change on the livelihood of farmers differ in different regions, of which, the vulnerability of households living in pure pastoral area is the strongest, and the vulnerability of households living in the farming areas is the least. (3) The vulnerability of farmers’ livelihood to climate change is negatively correlated with the age and the education level of householders, the income per capita of households and the level of nonfarming and livelihood diversification, while positively correlated with the dependency ratio. Finally, suggestions are proposed to reduce the vulnerability of the farmers’ livelihood to the climate change.

Key words: γ-aminobutyric acid, muskmelon seedlings, Ca(NO₃)₂ stress, nitrogen metabolism