The study of past global change is paramount to comprehending the present and future, as well as to better understand the mechanisms and influences of human-land interactions in a given region. The northeastern margin of the Qinghai-Tibetan Plateau has complex natural environments, sensitive to global change, and renowned for its long history of human occupancy. This makes it an ideal region for the study of anthropogenic impacts on the paleo-natural environment. This paper reconstructed the prehistoric temporal and spatial distribution of cultivated lands on the northeast margin of Qinghai-Tibetan Plateau, and analyzed the Dianziping pollen assemblage to disclose the anthropogenic impacts on the paleo-environment. The results demonstrated that around 4.3-4.0 cal ka BP, the rapid development of the Majiayao culture boosted the population to approximately 39,200 people, over 460km2 of the land area was converted to cropland, concomitantly, evidence of tree pollen decreased significantly. This marked the earliest identification of anthropogenic impacts on vegetation through agricultural activity in this region. At 4.0-3.6 cal ka BP, the population appeared to have diminished in conjunction with the cultivated land area. Nevertheless, forested areas continued to decrease, primarily due to adverse climatic conditions, but, anthropogenic activities played an undeniable role. Dianziping profile demonstrated the existence of natural forest in the Hehuang Valley during Qijia cultural Period. There was also evidence for the occurrence of regional fire events, suggesting large-scale burning of land cover in the area. This further illustrates anthropogenic impacts. At 3.6-2.6 cal ka BP, populations reached approximately 61,300 people, coinciding with the peak of cropland expansion. Consequently, more of the natural vegetation were converted to crops, and the superimposed influences of farming and grazing aggravated the process of deforestation and vegetation succession. Likewise, deforestation during the historical period can be explained, mostly by human driven causes with limited influence from climatic factors. The extensive exploitation of forest and expansion of cropland consequently resulted in extensive land deterioration, leaving the region with forest islands scattered in less populated, mountainous regions.

中文翻译：

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全新世中期青藏高原东北缘耕地的重建及其对古环境的人为影响

对于过去的全球变化的研究对于理解当前和未来，以及更好地理解给定区域中人地互动的机制和影响至关重要。青藏高原的东北边缘拥有复杂的自然环境，对全球变化敏感，并以其悠久的人类居住历史而闻名。这使其成为研究人为对古自然环境影响的理想区域。本文重建了青藏高原东北缘耕地的史前时间和空间分布，并分析了滇子坪花粉组合，揭示了人为对古环境的影响。结果表明，在4.3-4.0 cal ka BP附近，马加窑文化的迅速发展使人口增加到约39,200人，超过460平方公里的土地被转变为耕地，与此同时，树木花粉的证据也大大减少。这标志着该地区通过农业活动对植被的人为影响的最早发现。在4.0-3.6 cal ka BP时，人口数量随着耕地面积的减少而减少。然而，主要由于不利的气候条件，森林面积继续减少，但人为活动却发挥了不可否认的作用。点子坪剖面显示了齐家文化时期河the谷天然林的存在。也有证据表明发生了区域性火灾事件，表明该地区大规模烧毁了土地覆盖。这进一步说明了人为的影响。在3.6-2.6 cal ka BP时，人口达到约61,300人，与农田扩张的高峰相吻合。因此，更多的自然植被转化为农作物，而耕作和放牧的叠加影响加剧了森林砍伐和植被演替的过程。同样，可以解释历史时期的森林砍伐，这主要是由人为驱动的原因造成的，而这些因素受气候因素的影响有限。因此，对森林的广泛开发和农田的扩张导致土地的广泛退化，使该地区的森林岛屿散布在人口较少的山区。与农田扩张的高峰相吻合。因此，更多的自然植被转化为农作物，而耕作和放牧的叠加影响加剧了森林砍伐和植被演替的过程。同样，可以解释历史时期的森林砍伐，这主要是由人为驱动的原因造成的，而这些因素受气候因素的影响有限。因此，对森林的广泛开发和农田的扩张导致土地的广泛退化，使该地区的森林岛屿散布在人口较少的山区。与农田扩张的高峰相吻合。因此，更多的自然植被转化为农作物，而耕作和放牧的叠加影响加剧了森林砍伐和植被演替的过程。同样，可以解释历史时期的森林砍伐，这主要是由人为驱动的原因造成的，而受气候因素的影响有限。因此，对森林的广泛开发和农田的扩张导致土地的广泛退化，使该地区的森林岛屿散布在人口较少的山区。可以解释历史时期的森林砍伐，主要是由人为驱动的原因造成的，而受气候因素的影响有限。因此，对森林的广泛开发和农田的扩张导致土地的广泛退化，使该地区的森林岛屿散布在人口较少的山区。可以解释历史时期的森林砍伐，主要是由人为驱动的原因造成的，而受气候因素的影响有限。因此，对森林的广泛开发和农田的扩张导致土地的广泛退化，使该地区的森林岛屿散布在人口较少的山区。