Absatract Agriculture has been practiced in Iceland since settlement (landnam; AD 877). This has caused changes in vegetation communities, soil erosion, desertification and loss of carbon stocks. Little data exist regarding vegetation and ecosystems in the Icelandic highland before landnam and therefore the impact of land use over time is poorly understood. The objectives of the study are to examine the timing, nature and causes of land degradation in the highland of Northwest Iceland. Specifically, to determine the resilience of the pre-landnam highland environment to disturbances (i.e. climate cooling and volcanism) and whether land use pressure was of sufficient magnitude to facilitate ecosystem change. A sediment core was taken from the highland lake Galtabol. A chronology for the core was constructed using known tephra layers and radiocarbon dated plant macrofossils. Pollen analysis (vegetation), coprophilous fungal spores (proxy for grazing), and sediment properties (proxies for erosion) were used to provide a high-resolution, integrated vegetation and paleoenvironmental reconstruction. The pre-landnam environment showed resilience to climate cooling and repeated tephra fall. Soon after landnam the vegetation community changed and instability increased, indicated by changes in sediment properties. The pollen and spore record suggest introduction of grazing herbivores into the area after landnam. Following landnam, indicators of soil erosion appear in the sediment properties. Intensification of soil erosion occurred during the 17th century. The Galtabol record clearly demonstrates what can happen in landscapes without adequate management of natural resources and underestimation of landscape sensitivity. Introduction of land use resulted in changes in vegetation communities, loss of resilience and onset of increased soil erosion. Paleoenvironmental reconstructions may inform future decisions on management of the highland by providing baselines for natural variability in the pre-landnam environment.

中文翻译：

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冰岛高地的景观变化：土地利用、气候和火山活动影响的长期记录

自定居（landnam；公元 877 年）以来，冰岛就开始实行抽象农业。这导致了植被群落的变化、水土流失、荒漠化和碳储量的流失。在landnam之前，冰岛高地的植被和生态系统数据很少，因此人们对土地利用随时间推移的影响知之甚少。该研究的目的是检查冰岛西北部高地土地退化的时间、性质和原因。具体而言，要确定前陆南高原环境对干扰（即气候变冷和火山作用）的恢复能力，以及土地利用压力是否足以促进生态系统变化。沉积岩心取自高地湖 Galtabol。核心的年表是使用已知的火山灰层和放射性碳测年的植物大型化石构建的。花粉分析（植被）、嗜粪真菌孢子（放牧的代理）和沉积物特性（侵蚀的代理）被用来提供高分辨率的综合植被和古环境重建。前陆地环境显示出对气候变冷和反复火山灰的恢复能力。在landnam 之后不久，植被群落发生了变化，不稳定性增加，这表现为沉积物特性的变化。花粉和孢子记录表明，在landnam 之后，食草食草动物被引入该地区。在landnam之后，土壤侵蚀指标出现在沉积物特性中。土壤侵蚀加剧发生在 17 世纪。Galtabol 记录清楚地展示了在没有对自然资源进行充分管理和低估景观敏感性的情况下，景观中会发生什么。土地利用的引入导致了植被群落的变化、恢复力的丧失和土壤侵蚀加剧的开始。古环境重建可以通过为前陆地环境中的自然变化提供基线，为未来的高地管理决策提供信息。