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

This dataset compiles statistical summaries from an inventory of slime moulds (Eumycetozoa) on tree-linked and litter-type substrates in two forest nature reserves of the Masurian Lakeland (north-eastern Poland). It includes substrate-level diversity metrics and species incidence totals, summaries by ecological substrate class, a richness–pH model, NMDS ordination scores, combined taxon–substrate records across both reserves, and soaking-water pH values from moist chamber cultures.

Supplementary Material 1.1 provides substrate‑level alpha‑diversity metrics and species incidence totals. For each substrate code it reports species richness, Shannon diversity, the Gini–Simpson index and Pielou’s evenness, together with associated metadata on host tree, substrate material, ecological substrate class and, where available, mean pH of moist‑chamber soaking water. A second table lists every recorded taxon and its total number of collections across both reserves and all substrates.

Supplementary Material 1.2 summarises richness and diversity by ecological substrate class and documents an exploratory non‑parametric comparison between lignicolous and non‑lignicolous substrates. One table gives, for each substrate class, the number of substrate codes and the mean and standard deviation of richness, Shannon diversity, Gini–Simpson index and evenness. A second table reports the Wilcoxon rank‑sum statistic, p‑value and test specification for the comparison of richness between substrates.

Supplementary Material 1.3 contains parameter estimates from a univariate Gaussian linear model describing species richness as a function of mean substrate pH. Mean pH is represented as a categorical predictor with levels corresponding to the distinct pH values measured in moist‑chamber soaking water. The table lists, for the intercept and each pH level, the estimated coefficient, standard error, test statistic and p‑value.

Supplementary Material 1.4 provides ordination scores for all substrate codes from a two‑dimensional non‑metric multidimensional scaling analysis based on Bray–Curtis dissimilarities of presence–absence data. For each substrate code the table reports NMDS coordinates on two axes together with metadata on host tree, substrate description, mean pH, tree and material codes and ecological substrate class, allowing reconstruction and ecological interpretation of the ordination.

Supplementary Material 1.5 presents combined records of slime moulds (Eumycetozoa) from Dębowo and Gązwa by host tree and substrate type. For each taxon, it lists the number of collections on bark, wood, twigs, leaves/needles and seeds/cupules, plus BRY, FOL, HER and TER, providing the observed substrate associations.

Supplementary Material 1.6 reports mean soaking-water pH from moist chamber cultures for substrates.

Supplementary Material 1.7. records moist chamber cultures established from tree-linked substrates in Gązwa and Dębowo Nature Reserves