Close-to-nature forest management effects on soil nematodes and microbial activity in pine plantations on aeolian sands

Close-to-nature forest management combines the economic use of forests with nature conservation in forest, aiming promote stability, productivity, diversity and continuity within forest ecosystems. While close-to-nature management is expected to positively impact the tree growth, its effect on the belowground micro-biota has been poorly investigated. Nematodes and microbes are species-rich and abundant soil microorganisms that have long been used as ecological indicators of soil health. In this study, was assessed the impact of close-to-nature forest management on soil nematode communities and microbial activity in the pine plantations on aeolian sands in Southern Slovakia, 10 years after the introduction of this management approach. Fifteen stands in close-to-nature forest managed and fifteen stands with applying standard forest management were chosen. Our findings revealed that close-to-nature forest management significantly increased the abundance of soil nematodes and nematode biomass in each of the plots. Moreover, close-to-nature forest management significantly increased the mean abundance of omnivores and predators as stress sensitive nematodes (c–p4, c–p5). Additionally, close-to-nature forest management reduces the proportion of stress tolerant nematodes (c–p1) and enrichment opportunists (c–p2), increased all maturity and structure indices as well as composite, structure, predator and omnivore footprints. Furthermore, close-to-nature forest management significantly increased soil moisture, soil carbon content, microbial biomass carbon, basal respiration and N-mineralization, and understory vegetation diversity. These findings suggest that close-to-nature management practice, resulting in forest of different ages, positively influenced nematode communities and microbial activity by changing the quantity and quality of resources associated with increased understory cover and diversity.