Antarctica is the last pristine environment on Earth, its biota being adapted to the harsh and extreme polar climate. Until now, soil formation and vegetation development in continental Antarctica were considered very slow due to the extreme conditions of this polar desert. Since the austral summer 2002/2003, a long-term monitoring network of the terrestrial ecosystems (soils, vegetation, active layer thickness) has been established at Victoria Land (VL) across a > 500 km latitudinal gradient of coastal sites (73°–77°S). In only one decade large ecosystem changes were detected. Climate was characterized by a significant increase of thawing degree days in northern VL and of autumn air temperature. No extreme climatic events (such as hot spells) where detected in the study period. Soil chemistry suffered large quantitative changes, clearly indicating rapid pedogenetic processes. In most soils the upper layers exhibited a strong alkalinization (pH increases up to 3 units) and increases in conductivity, anions and cations (in particular of SO₄ and Na). The largest changes were observed in soils with low vegetation cover. Statistically significant differences in soil chemistry were detected between soils with high and low vegetation cover, the former showing lower pH, conductivity, Na and Cl. Most plots exhibited changes of total cover, species richness and floristic composition, with vegetation expansion in soils with low vegetation cover and the largest increase recorded at Apostrophe Island (northern VL). Principal Component Analysis (PCA) identified the main trend of vegetation change, with a shift from lower to higher cover and a secondary trend of change associated with a gradient of water availability, consistent with an increase in water instead of snow. Redundancy analysis (RDA) identified the trend of change in soil chemistry with increases in pH, conductivity, anions and cations associated with the concomitant decrease in C, N, NO₃, PO₄. The RDA confirmed that soil changes were associated with a gradient of vegetation change (from low to high cover) as well as of water availability, as already indirectly outlined by the PCA. Field manipulation experiments carried out at five locations of the network between 73°S and 77°S, simulating increases of precipitation from snow or water additions didn’t induce changes in soil pH, indicating that pulse events of snow accumulation or melting could not trigger persistent soil pH changes. These data allow hypothesize the occurrence of a main ecosystem change occurring at regional scale at Victoria Land. The slight air warming and its consequences on soil chemistry and vegetation, further highlight the sensitivity of the fragile Antarctic ecosystems to the consequences of even small changes in climate.

南极洲是地球上最后的原始环境，其生物区系适应了恶劣和极端的极地气候。迄今为止，由于极地沙漠的极端条件，南极大陆的土壤形成和植被发展被认为非常缓慢。自2002/2003年夏季南方以来，维多利亚州土地（VL）已建立了沿沿海站点纬度梯度> 500 km的陆地生态系统（土壤，植被，活动层厚度）的长期监测网络（73°– 77°S）。仅在十年内，就发现了生态系统的巨大变化。气候的特点是，VL北部的融化度日数和秋季气温显着增加。在研究期间未检测到极端的气候事件（例如高温）。土壤化学的定量变化很大，清楚地表明了快速的成岩过程。在大多数土壤中，上层表现出强烈的碱化作用（pH值增加至3个单位），并且电导率，阴离子和阳离子（尤其是SO的增加）增加₄和Na）。在植被覆盖率低的土壤中观察到最大的变化。在植被覆盖度高和低的土壤之间，土壤化学差异有统计学意义，前者的pH值，电导率，Na和Cl含量较低。大多数样地都表现出总覆盖率，物种丰富度和植物区系的变化，植被覆盖率低的土壤中的植被扩展，而在Apostrophe岛（北部VL）记录的增幅最大。主成分分析（PCA）确定了植被变化的主要趋势，即从较低的覆盖度向较高的覆盖度转变，以及与水可利用量梯度相关的次生变化趋势，这与水而不是雪的增加一致。冗余分析（RDA）确定了土壤化学性质随pH，电导率，₃，PO ₄。RDA证实，土壤变化与植被变化（从低到高的覆盖率）以及水的可利用性的梯度有关，正如PCA已经间接概述的那样。在73°S和77°S之间的网络的五个位置进行了现场操作实验，模拟了雪或水的添加引起的降水增加并没有引起土壤pH的变化，这表明积雪或融雪的脉冲事件不会触发土壤pH值持续变化。这些数据可以假设在维多利亚州地区发生了主要的生态系统变化。轻微的气候变暖及其对土壤化学和植被的影响，进一步凸显了脆弱的南极生态系统对即使很小的气候变化后果的敏感性。