Understanding the Diversity and Distribution of Lycophytes and Ferns in Northeast China Based on Historical Records

Understanding the species diversity distribution of lycophytes and ferns is crucial for identifying biodiversity hotspots and conservation planning. Northeast China, a biodiversity-sensitive area affected by climate change, lacks comprehensive information on diversity and distribution patterns of these plants. To address this gap, we sorted out all naturally distributed lycophyte and fern species recorded in the region, analyzed their diversity, frequency, and threatened status. Correlation and regression analyses were also conducted with geographic gradients at the county level. Our study identified a total of 143 taxa (species and intraspecific taxa) belonging to 48 genera of 19 families of lycophytes and ferns in Northeast China, with terrestrial (85 spp.) and epilithic (55 spp.) life forms dominating. Species with frequencies below 10.00% comprised 75.52% of the total. Notably, five species were listed as threatened in the Red List of China’s Biodiversity, highlighting the urgency for conservation measures. Overall, species diversity decreased from low to high latitudes, but increased with maximum elevation and elevation range. High diversity areas were concentrated mainly in Da Hinggan Mountains, Xiao Hinggan Mountains, and Changbai Mountains, which correspond to the main mountainous terrain of Northeast China. Changbai Mountains exhibited the highest diversity, establishing itself as a pivotal diversity center for lycophytes and ferns in the region. Exploring the diversity and distribution of lycophytes and ferns is crucial for understanding their interactions with environmental gradients, and thereby supporting significant biodiversity conservation efforts in Northeast China.