BACKGROUND AND AIMS Herbaceous plants can survive periods of prolonged freezing as belowground structures or seed, which can be insulated from cold air by soil, litter or snow. Belowground perennial structures vary in both form and their exposure to soil frost, and this structural variation thus may be important in determining the responses of plant communities to frost stress. METHODS We conducted a suite of snow removal experiments in a northern temperate old field over three years to examine the relative freezing responses of different plant functional groups based on belowground perennation traits. A litter removal treatment was added in the third year. Species-level percent cover data were recorded in May, June, and September then pooled by functional group. KEY RESULTS Snow removal decreased total plant cover, and this response was particularly strong and consistent among years for tap-rooted and rhizomatous species. The snow removal responses of cover for plants with root buds and new recruits from seed varied from positive to negative responses among years. The cover of rootstock plants consistently increased in response to snow removal. Rhizomatous species were generally the most vulnerable to litter removal. CONCLUSIONS This study is the first to explore the effects of variation in frost severity on the responses of different plant perennation trait functional groups. The responses of herbaceous species to frost may become increasingly important in northern temperate regions in the coming decades as a result of declining snow cover and increasing temperature variability. Our results reveal substantial variation in responses among perennation trait functional groups, which could drive changes in species abundance in response to variation in soil frost.

中文翻译：

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生育性状在植物群落土壤霜冻胁迫响应中的作用

背景和目的草本植物可以作为地下结构或种子在长时间的冷冻中存活下来，它们可以通过土壤、枯枝落叶或雪与冷空气隔绝。地下多年生结构的形式和它们对土壤霜冻的暴露程度各不相同，因此这种结构变化对于确定植物群落对霜冻胁迫的反应可能很重要。方法 我们在北温带老田中进行了为期三年的除雪实验，以检查基于地下多年生性状的不同植物功能群的相对冻结反应。第三年增加了垃圾清除处理。5 月、6 月和 9 月记录了物种级别的百分比覆盖率数据，然后按功能组汇总。主要结果 除雪减少了植物总覆盖率，对于直根和根茎物种，这种反应在多年间尤其强烈和一致。具有根芽的植物和从种子中新招募的植物的除雪反应随年份变化从正面到负面。随着除雪，砧木植物的覆盖率不断增加。根茎类物种通常最容易受到垃圾清除的影响。结论本研究首次探讨了霜冻严重程度的变化对不同植物多年生性状功能群反应的影响。由于积雪减少和温度变化增加，草本植物对霜冻的反应在未来几十年可能会在北温带地区变得越来越重要。