Data for: Response of boreal plant communities and forest floor carbon fluxes to experimental nutrient additions

This is the final dataset for the publication \"Response of boreal plant communities and forest floor carbon fluxes to experimental nutrient additions\" published in the peer-reviewed journal Ecosystems in 2024. This dataset includes three primary files: the plant community composition data the plant functional trait data the forest floor carbon flux and associated environmental variables data. Combined, the plant community composition data and plant functional trait data were used to calculate the community-weighted mean traits presented in the manuscript. These data explored changes in community-weighted mean traits of both moss and understory vascular plant communities as well as forest floor carbon flux with nutrient fertilization emulating nutrient increases following permafrost thaw in a boreal peatland (Scotty Creek Research Station, NT: 61°18′ N, 121°,18′ W). We had two sites in this boreal peatland: one with high canopy cover, and one with low canopy cover. We conducted an experiment whereby we set up 25, 0.5 m^2 quadrats at two sites within a boreal peatland (50 total quadrats). We had five different nutrient treatments with five replicates each: an unmanipulated control (no fertilizer or mechanical disturbance), a manipulated control (no fertilizer, with mechanical disturbance similar to the fertilized treatments), shallow fertilization (nutrient added at 20cm soil depth emulating increasing microbial mineralization with warming soil), deep fertilization (nutrient added at 40 cm soil depth emulating release of previously frozen nutrient-rich soil to the active layer), and shallow + deep fertilization (emulating both the shallow and deep treatments simultaneously). 12-4-8 NPK MiracleGro slow-release fertilizer was applied at a dosage of 6 g N m-2. This value is roughly four times that of the predicted maximum rate of increase in N from rising soil temperature and permafrost thaw (e.g., 1.3 g N m-2 yr-1; Keuper and others 2012, Global Change Biology 18: 1998) but is similar to Keuper and others (2017, Global Change Biology 23: 4257). Furthermore, being slow-release fertilizer, we expected slow nutrient release over the two-year experiment, mimicking natural conditions. The two sites whereby we set up the experiment differed in canopy cover and therefore allowed us to test if light availability effected the response of carbon fluxes and plant communities to nutrient increases. See (link to paper) for more detailed methodology.本数据集为2024年发表于同行评议期刊《Ecosystems》的论文《北方植物群落与地表碳通量对实验性养分添加的响应》的配套最终数据集。本数据集包含三类核心文件：植物群落组成数据、植物功能性状数据，以及地表碳通量与相关环境变量数据。其中，植物群落组成数据与植物功能性状数据可结合用于计算论文中呈现的群落加权平均性状（community-weighted mean traits）。 本数据集探究了加拿大西北地区斯科特溪研究站（Scotty Creek Research Station, NT: 61°18′ N, 121°18′ W）的北方泥炭地中，模拟多年冻土融化后养分增加的养分施肥实验下，苔藓群落与林下维管植物群落的群落加权平均性状变化，以及地表碳通量变化。 本实验在该北方泥炭地设置两处样地：一处为高冠层覆盖度样地，另一处为低冠层覆盖度样地。实验共在两处样地内布设50个0.5平方米样方（每处样地25个）。实验设置5种养分处理，每种处理设置5个重复：无操控对照组（不施加肥料或进行机械扰动）、模拟操控对照组（不施加肥料，但施加与施肥处理一致的机械扰动）、浅层施肥组（在20cm土层深度施加养分，模拟土壤升温后微生物矿化作用增强的过程）、深层施肥组（在40cm土层深度施加养分，模拟先前冻结的富养分土壤释放至活动层的过程），以及浅深联合施肥组（同时模拟浅层与深层施肥过程）。 实验采用12-4-8型氮磷钾（NPK）美乐棵（MiracleGro）缓释肥，施用量为6克氮每平方米。该施用量约为土壤升温与多年冻土融化导致的氮素最大增加预测速率的4倍（例如1.3克氮每平方米每年；Keuper等，2012，《Global Change Biology》18: 1998），但与Keuper等2017年的研究结果相近（《Global Change Biology》23: 4257）。此外，由于使用缓释肥，我们预期其养分释放过程将贯穿整个两年实验周期，以模拟自然养分释放条件。 本实验设置的两处样地在冠层覆盖度上存在差异，借此可检验光照有效性是否会影响碳通量与植物群落对养分增加的响应。更多详细实验方法可参见（论文链接）。