The negative marginal effect of spatial expansion of human activities on the ecology is increasing, which could easily lead to unsustainable development. However, the reasons for the expansion process and the combined impact on the ecosystem health of protected areas and the sustainable livelihoods of local residents are still vaguely known. Northern Tibet has important ecological service functions such as water conservation, windbreak and sand fixation, and plateau biodiversity, and is an ecological security barrier on a global scale. Based on multi-source data, this study describes the changing process of the boundary of human activities in northern Tibet. By establishing a sustainable living equilibrium model, using spatial analysis and the transformation measurement method, the causes of human activities encroaching on protected areas and their impact on ecology and pastoralist livelihoods are explored. The results showed that the boundary of grazing moved 118.7 km northward to the Qiangtang Protected Area from 1980 to 2015, resulting in the theoretical livestock carrying capacity of grasslands decreased by 5.4%, the overgrazing worsened by 6.8%, and the living standard of pastoralists widened with that of the whole Country. The factors leading to the expansion include population increase and consumption demand, increases in wildlife, lake expansion and grassland degeneration. The pastoralists' excessive dependence on animal husbandry is the main reason, contributing to more than 65% of the northward expansion. The feasible way to change this local unsustainable development is to make rational use of the ecological tourism function and service value of the protected areas.

中文翻译：

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藏北地区人类活动向北扩展到保护区对当地可持续性的影响

人类活动空间扩张对生态的负面边际效应越来越大，容易导致不可持续的发展。然而，扩张过程的原因以及对保护区生态系统健康和当地居民可持续生计的综合影响仍然模糊不清。藏北具有水源涵养、防风固沙、高原生物多样性等重要生态服务功能，是全球范围内的生态安全屏障。本研究基于多源数据，描述了藏北地区人类活动边界的变化过程。通过建立可持续的生活平衡模型，利用空间分析和变换测量方法，探讨了人类活动侵占保护区的原因及其对生态和牧民生计的影响。结果表明，1980-2015年放牧边界向北移动118.7公里至羌塘保护区，导致草地理论承载牲畜能力下降5.4%，过度放牧恶化6.8%，牧民生活水平扩大。与整个国家。导致扩张的因素包括人口增加和消费需求、野生动物增加、湖泊扩张和草地退化。牧民对畜牧业的过度依赖是主要原因，贡献了65%以上的北扩。