Statistical analyses
Data were analyzed using Statistical Package for the Social Sciences
(SPSS) (version 26.0; SPSS, Inc., Chicago, IL, USA). Data were checked
for normal distribution using the Shapiro-Wilk test. Data for marmot den
characteristics that were not indicated as being normally distributed
were log10-transformed to pursue normality and
homogeneity of variances. We set terrains as fixed effects and
replicates as a random effect. Factorial ANOVA (One-way ANOVA) analysis
of variance with a least significant difference (LSD) test for multiple
comparisons was used to compare various indicators of marmot den
characteristics among different terrains. Figures were constructed using
Origin 9.1.
Principal component analysis (PCA) was performed to study the
relationship between the environmental variables (terrain and plant
traits) and the den characteristics. PCA was performed using CANOCO
version 5.0 (Šmilauer and Lepš 2014).