Data from: Sixty-year legacy of human impacts on a high Arctic ecosystem

The high Arctic is the world's fasting warming biome, allowing access to sections of previously inaccessible land for resource extraction. Starting in 2011, exploration of one of the Earth's largest undeveloped coal seams was initiated in a relatively pristine, polar desert environment in the Canadian high Arctic. Due to the relative lack of historic anthropogenic disturbance, significant gaps in knowledge exist on how the landscape will be impacted by development. At an abandoned airstrip located near the area of current exploration, we used a disturbance case–control approach to evaluate the long-term ecological consequences of high Arctic infrastructure disturbance to vegetation and sensitive, ice-rich permafrost. We quantified: (i) long-term effects on vegetation diversity, soil nutrients, and abiotic ground conditions and (ii) the alteration of the ground surface topography and legacy of subsurface thermal changes. We found that in over sixty years since abandonment, the disturbed landscape has not recovered to initial conditions but instead reflects a disturbance-initiated succession towards a different stable-state community. Microtopography greatly influenced recovery patterns in the landscape. The terrain overlaying buried ice (ice wedge polygon troughs) was the most sensitive to disturbance and had a different species composition, decreased plot-level species richness, significant increases in vegetation cover, and a drastically reduced seasonal fluctuation in subsurface temperatures. In contrast, disturbed polygon tops showed resiliency in vegetation recovery, but still had remarkable increases of depth of seasonal soil thaw (active layer). Synthesis and applications. Our results indicate that disturbance effects differ depending on microtopographic features, leading to an increased patchiness of the landscape as found elsewhere in the Arctic. Managers who wish to lessen their impact on high Arctic environments should avoid areas of sensitive, ice-rich permafrost, constrain the geographic scale of near-surface ground disturbance, limit vegetation removal where possible and reseed disturbed areas with native species.

高北极地区是全球变暖速率最快的生物群系，使得此前无法进入的区域得以被开发利用以获取自然资源。2011年起，科研人员在加拿大高北极地区一处相对原始的极地荒漠环境中，启动了对全球最大未开发煤层之一的勘探工作。由于该区域历史上受人为干扰程度极低，学界对开发活动将如何影响这片景观的认知存在显著空白。在当前勘探区域附近一处废弃简易机场，本研究采用干扰病例-对照（disturbance case–control）研究方法，评估了高北极地区基础设施干扰对植被与敏感的富冰多年冻土（ice-rich permafrost）带来的长期生态影响。本研究量化了两方面内容：(i) 对植被多样性、土壤养分与非生物地表条件的长期影响；(ii) 地表地形的改变以及地下热状况变化的遗留效应。研究发现，在废弃60余年后，受干扰的景观并未恢复至初始状态，而是呈现出由干扰驱动的演替过程，最终形成了一种全新的稳定群落。微地形极大地影响了该区域景观的恢复模式。覆盖埋藏冰的区域（冰楔多边形槽（ice wedge polygon troughs））对干扰最为敏感，其物种组成发生改变，样方内物种丰富度下降，植被盖度显著提升，且地下温度的季节波动大幅降低。与之相反，受干扰的多边形丘顶在植被恢复方面表现出恢复力，但季节性土壤解冻深度（活动层（active layer））仍出现了显著增加。综合与应用。本研究结果表明，干扰效应因微地形特征而异，正如北极其他区域所见，这会导致景观的斑块化程度加剧。希望减轻对高北极环境影响的管理者应避开敏感的富冰多年冻土区域，限制近地表地面干扰的地理范围，尽可能减少植被移除，并使用本土物种对受干扰区域进行重新播种。