Abstract

Background and purpose
Biodiversity within ecosystems is intricately linked to a various factor, with soil physicochemical characteristics standing out as pivotal contributors. The soil, particularly in forests, functions as a dynamic habitat supporting a diverse array of organisms, including land snails, which play a significant role in forest ecosystems. This study focuses on unraveling the intricate correlation between the presence of land snails and six key soil parameters: pH, total calcium (Ca), total magnesium (Mg), exchangeable calcium (Ca⁺⁺), exchangeable magnesium (Mg⁺⁺), and soil Saturation Moisture percent. These factors are investigated as crucial elements influencing the distribution patterns of land snails.
Methodology
The research was conducted in the Hyrcanian forests of Iran, specifically targeting three distinct forest regions situated in Kordkoy, Amol, and Tonekabon. These areas were designated as sampling sites during field surveys. To ensure a comprehensive and representative approach, sampling was conducted at three distinct locations within each forest, resulting in a total of 27 sample plots, each measuring 3 m × 3 m for detailed ecological assessment. The identification of snails and the evaluation of biodiversity were enhanced by employing DNA barcoding techniques. Snail abundance and species diversity were measured at each forest site, offering valuable insights into the ecological dynamics of these ecosystems. This quantification process provided a comprehensive understanding of the population density of snails and the variety of species present in each forest location. The analysis of soil factors involved laboratory methods, and Principal Component Analysis (PCA) was utilized to simplify the multidimensional data. It identified important variables for subsequent Canonical Correspondence Analysis (CCA), a sophisticated statistical technique. This comprehensive approach played a pivotal role in unraveling intricate relationships between soil physicochemical factors and the presence of snails. The analysis not only clarified the correlations between environmental variables and species distribution within the forests but also offered profound insights into the nuanced interplay shaping the ecological dynamics of these ecosystems.
Findings and discussion
A total of 679 snails were collected from the sampling stations, and phylogenetic tree analysis along with species delimitation revealed 37 sequences belonging to 10 Operational Taxonomic Units (OTUs). ANOVA results indicated significant variations in snail abundance among the forests. Following PCA, key factors for CCA were identified, and CCA, utilizing total calcium, total magnesium, and soil saturation moisture percentage as factors, demonstrated a positive correlation with most OTUs and snail abundance. These factors are vital in shaping the distribution and biodiversity of land snails. Land snails need Ca and Mg to restore the shell. Also, areas with moist soil are more favorable habitats for Snails provide.
Conclusion
In conclusion, this research establishes a foundational understanding of the intricate relationship between soil properties and snail communities in sections of the Hyrcanian forests. The insights gained from such studies contribute fundamental information essential for developing a native biodiversity index based on land snails. This index, in turn, holds promise for informing the formulation of effective management strategies aimed at conserving the diverse fauna of land snails within these ecologically vital forest ecosystems.