Canopy composition and site are indicative of mineral soil conditions in Patagonian mixed Nothofagus forests

Abstract

Key message: Canopy composition in mixed Patagonian Nothofagus forests has an impact on soil properties like cationic exchange capacity and pH, while most soil variables changed with site [P, cation exchange capacity (CEC), soil moisture (SM), resistance to penetration (R)]. Site conditions and canopy composition need be considered together to better understand the distribution of Nothofagus species.Context: Forests can influence soil development, changing main soil properties by several mechanisms, but this has never been investigated in mixed Nothofagus forests. Such influences can be strongly variable depending on local site conditions, and the interactions between both factors need to be clearly established.Aims: To reveal the effect on physical and chemical mineral soil properties in mixed Nothofagus forests of canopy composition and their interactions with site conditions.Methods: Two sites and threemixed forest types, with different proportion of deciduous-evergreen,were selected in coastal andmountain sites. We evaluated forest structure, litterfall and physico-chemical properties of mineral soil (N= 60), and analyzed these factors with general linear models and multivariate statistics [multi-response permutation procedure (MRPP), principal component analyses (PCA)].Results: Basal area and litterfall were significantly influenced by forest type × sites. CEC and pH value varied among forests types and sites, but sites also influenced other variables (P, SM, R). Multivariate analyses reveals a much stronger effect of site conditions than that of species mixture.Conclusion: Forest soil studies must consider environmental factors on different spatial scale and canopy species composition to better understand their influence on soil dynamics in mixed Nothofagus forests.