Terrestrial Lichen Data for Northwest Territories, Canada

This record is for the dataset “Terrestrial Lichen Data for Northwest Territories, Canada ” at https://doi.org/10.5061/dryad.t1g1jwt15 Increased fire activity due to climate change may impact the successional dynamics of boreal forests, with important consequences for caribou habitat. Early successional forests have been shown to support lower quantities of caribou forage lichens, but geographic variation in, and controls on, the rates of lichen recovery have been largely unexplored. In this study, we sampled across a broad region in northwestern Canada to compare lichen biomass accumulation in ecoprovinces, including the Saskatchewan Boreal Shield, the Northwest Territories Taiga Shield and Northwest Territories Taiga Plains, divided into North and South. We focused on the most valuable Cladonia species for boreal and barren ground caribou: Cladonia mitis, and C. arbuscula, C. rangiferina and C. stygia, C. stellaris and C. uncialis. We developed new allometric equations to estimate lichen biomass from field measurements of lichen cover and height; allometries were consistent among ecoprovinces, suggesting generalizability. We then used estimates of lichen biomass to quantify patterns of lichen recovery in different stand types, ecoprovinces, and with time following stand-replacing fire. We used a hurdle model to account both for the heterogeneous nature of lichen presence (zero-inflation), and the range of abundance in stands where lichen was present. The first component of the hurdle model, a generalized linear model (GLM), identified stand age, stand type and ecoprovince as significant predictors of lichen presence. With a logistic growth model, a measure of lichen recovery (time to 50% asymptotic value) varied from 28 to 73 years, dependent on stand type and ecoprovince. The combined predictions of the hurdle model suggest the most rapid recovery of lichen biomass across our study region occurred in jack pine in the Boreal Shield (30 years), while stands located in the Taiga Plains (North and South) required a longer recovery period (approximately 75 years). These results provide a basis for estimating future caribou habitat that encompasses some of the large variation in fire effects on lichen abundance and vegetation types across the range of boreal and barren ground caribou in North America. This dataset can be downloaded at https://doi.org/10.5061/dryad.t1g1jwt15本数据集记录为《加拿大西北地区陆地地衣数据集》（Terrestrial Lichen Data for Northwest Territories, Canada），可通过以下链接获取：https://doi.org/10.5061/dryad.t1g1jwt15。气候变化引发的火灾活动加剧可能改变北方森林的演替动态，进而对驯鹿栖息地产生重要影响。已有研究证实，早期演替森林所支撑的驯鹿食用地衣生物量更低，但地衣恢复速率的地理变异及其调控机制尚未得到充分探索。本研究在加拿大西北部广阔区域开展系统采样，对比多个生态省的地衣生物量积累特征，涵盖萨斯喀彻温北方盾地（Saskatchewan Boreal Shield）、西北地区泰加盾地（Northwest Territories Taiga Shield），以及划分为南北两个亚区的西北地区泰加平原（Northwest Territories Taiga Plains）。研究聚焦于对北方森林与冻原驯鹿具有核心价值的石蕊属（Cladonia）物种，包括Cladonia mitis、C. arbuscula、C. rangiferina、C. stygia、C. stellaris与C. uncialis。我们开发了全新的异速生长方程（allometric equations），可通过野外实测的地衣盖度与高度估算地衣生物量；各生态省的异速生长模型一致性良好，证实该方法具备普适性。随后，我们利用地衣生物量估算结果，量化了不同林分类型、生态省内地衣的恢复模式，以及林分经毁灭性林火后的恢复随时间的变化规律。本研究采用障碍模型（hurdle model），同时考量地衣分布的异质性与零膨胀特性（zero-inflation），以及存在地衣的林分中丰度的分布区间。该障碍模型的第一部分为广义线性模型（generalized linear model，GLM），结果显示林分年龄、林分类型与生态省是地衣存在的显著预测因子。通过逻辑斯蒂增长模型（logistic growth model）计算得到的地衣恢复指标（达到50%渐近值所需时间）因林分类型与生态省而异，区间为28至73年。障碍模型的联合预测结果表明，本研究区域内地衣生物量恢复最快的区域为北方盾地的班克松（jack pine）林分，恢复周期仅需30年；而位于泰加平原（南北两部分）的林分则需要更长的恢复周期，约为75年。本研究结果可为预测未来驯鹿栖息地提供理论基础，该基础涵盖了北美北方森林与冻原驯鹿分布范围内，火灾对地衣丰度与植被类型的多种大型变异。本数据集可通过以下链接下载：https://doi.org/10.5061/dryad.t1g1jwt15