Dataset from an inventory of slime moulds (Eumycetozoa) in two forest nature reserves of the Masurian Lakeland, north‑eastern Poland

Supplementary Material 1 Full myxomycete occurrence records. This record-level dataset contains all 492 collection records, including taxon, acquisition method, dates, moist chamber information, substrate type and substrate species, pH, elevation, geographic coordinates, coordinate precision, collector(s), determiner(s), reserve name, forest address, forest district, forest site type, degradation degree, moisture variant and Natura 2000 habitat code. Records distinguish field-survey collections from moist chamber culture records and should be interpreted as collection incidences rather than direct measures of field abundance. Supplementary Material 1.1 Monthly field sampling effort in Gązwa and Dębowo Nature Reserves and meteorological context during the study period. The table summarises the number of field outings per reserve for each sampled month, together with mean monthly air temperature, monthly precipitation totals and mean monthly relative humidity. Supplementary Material 1.2 Substrate-level alpha-diversity metrics and taxon incidence totals. For each substrate code, the file reports taxon richness, Shannon diversity, the Gini–Simpson index and Pielou’s evenness, together with host tree, substrate material, ecological substrate class and, where available, mean soaking-water pH. It also includes total incidence values for each recorded taxon. Supplementary Material 1.3 Summaries of richness and diversity by ecological substrate class, together with the exploratory Wilcoxon comparison between lignicolous and non-lignicolous substrates. The file reports class-level means and standard deviations for diversity metrics and the test output for the richness comparison. Supplementary Material 1.4 Univariate Gaussian linear model relating taxon richness to mean soaking-water pH for tree-linked substrates with pH data. The file includes model estimates and summary statistics used to describe the richness–pH relationship. Supplementary Material 1.5 Non-metric multidimensional scaling ordination scores for substrate codes. The ordination is based on Bray–Curtis dissimilarities calculated from presence–absence data and includes NMDS coordinates together with substrate metadata. Supplementary Material 1.6 Combined records of slime moulds by host tree and substrate type. The file summarises observed taxon–substrate associations across both reserves and both acquisition methods. Supplementary Material 1.7 Mean soaking-water pH values from moist chamber cultures. The file summarises pH measurements for tree-linked substrate combinations used in the culture-based part of the study. Supplementary Material 1.8 Moist chamber cultures established from tree-linked substrates in Gązwa and Dębowo Nature Reserves. The file documents culture identifiers, substrate combinations and cultivation metadata.补充材料1 完整黏菌（Myxomycete）出现记录。本记录级数据集包含全部492份采集记录，涵盖分类单元、采集方法、采集日期、保湿培养信息、基质类型与基质物种、pH值、海拔、地理坐标、坐标精度、采集者、鉴定者、保护区名称、林场地址、林分区划、立地类型、退化程度、湿度变异类型以及Natura 2000生境代码。本数据集区分野外调查采集标本与保湿培养记录，应被解读为采集发生频次，而非野外种群丰度的直接测量值。 补充材料1.1 Gązwa与Dębowo自然保护区月度野外采样工作量及研究期间气象背景。该表格汇总了各保护区每个采样月的野外出行次数，同时包含月平均气温、月降水量总和与月平均相对湿度。 补充材料1.2 基质级α多样性指数与分类单元出现总次数。针对每个基质编码，本文件报告了分类单元丰富度、香农多样性指数、基尼-辛普森指数与皮卢均匀度指数，同时包含寄主树木、基质材料、生态基质类别以及可用的浸出液平均pH值。此外还包含每个记录分类单元的总出现频次值。 补充材料1.3 按生态基质类别汇总的丰富度与多样性数据，以及木质基质与非木质基质间的探索性威尔科克森秩和检验比较。本文件报告了各类别多样性指数的均值与标准差，以及丰富度比较的检验结果。 补充材料1.4 针对带有pH数据的树木关联基质，构建关联分类单元丰富度与浸出液平均pH值的单变量高斯线性模型。本文件包含用于描述丰富度-pH关系的模型估计值与汇总统计量。 补充材料1.5 基质编码的非度量多维标度（Non-metric Multidimensional Scaling, NMDS）排序得分。该排序基于由物种有无数据计算得到的布莱-柯蒂斯（Bray–Curtis）相异度，包含NMDS坐标与基质元数据。 补充材料1.6 按寄主树木与基质类型汇总的黏菌联合记录。本文件汇总了两个保护区、两种采集方式下观测到的分类单元-基质关联情况。 补充材料1.7 保湿培养实验得到的浸出液平均pH值。本文件汇总了本研究培养阶段所用的树木关联基质组合的pH测量数据。 补充材料1.8 从Gązwa与Dębowo自然保护区的树木关联基质中建立的保湿培养物。本文件记录了培养物标识符、基质组合与培养元数据。