Assessing Soil Microbial Catabolic Diversity in Alder and Oak Plantations at Varying Developmental Stages

Abstract

To assess the impact of forest plantations on soil microbial catabolic diversity, this study investigated the microbial response to the addition of various carbon-rich substrates in different ages of forest plantations and compared catabolic diversity between a nitrogen-fixing tree species (Alder, Alnus subcordata C. A. M.) and a non-nitrogen-fixing one (Oak, Quercus castaneifolia C. A. M.). The diversity indices (Simpson and Shannon diversity indicies) and Shannon evenness index demonstrated higher values in the oldest plantations than the youngest ones. In younger plantations (15 and 20 years old), oak stands exhibited higher microbial diversity compared to alder stands. However, at 25 years old, alder plantation displayed greater diversity than the oak plantation, as indicated by higher values for the Shannon diversity index (2.77), Simpson diversity index (0.93), and Shannon evenness index (0.89). Forest plantations with alder and oak species significantly enhanced catabolic evenness and diversity, thereby increasing the soil capacity to decompose organic matter and the resilience of the soil to disturbance. This this study highlights the influence of forest plantations on soil microbial catabolic diversity, demonstrating the potential of diverse tree species to promote soil health and resilience through enhanced functional complexity.