Soil Nematode Fauna and Microbial Characteristics in an Early-Successional Forest Ecosystem

Renčo Renčo,Gömöryová Gömöryová,Čerevková Čerevková

doi:10.3390/f10100888

Renčo Renčo, Gömöryová Gömöryová + Show 1 more

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https://doi.org/10.3390/f10100888

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Abstract

Windstorms can often decrease the diversity of native local biota in European forests. The effects of windstorms on the species richness of flora and fauna in coniferous forests of natural reserves are well established, but the effects on biotas in productive deciduous forests have been less well studied. We analyzed the impact of windstorms on the diversity and abundance of soil nematode communities and microbial activity and their relationships with the succession of plant species and basic soil physicochemical properties 12 and 36 months after a windstorm in Fagus sylvatica forests. The relationships were investigated in cleared early-successional forest ecosystems and at undamaged forest sites as a control. The windstorm significantly affected total nematode abundance, number of nematode species, and the diversity and abundance of all nematode functional guilds, but no functional guilds disappeared after the disturbance. The abundance of several nematode taxa but not total nematode abundance was positively correlated with soil-moisture content. Indices of the nematode communities were inconsistent between sites due to their variable ability to identify ecosystem disturbance 12 months after the storm. In contrast, the metabolic activity of various functional groups identified ecosystem disturbance well throughout the study. Positive correlations were identified between the number of plant parasites and soil-moisture content and between carnivore abundance and soil pH. Positive mutual links of some nematode genera (mainly plant parasites) with the distribution of dominant grasses and herbs depended on the habitat. In contrast, microbial activity differed significantly between disturbed and undisturbed sites up to 36 months after the storm, especially soil basal respiration, N mineralization, and microbial biomass. Our results indicated different temporal responses for two groups of soil organisms to the destruction of the tree canopy. Soil nematodes reacted immediately, but changes in the microbial communities were visible much later after the disturbance.

Highlights

The loss of biodiversity continues on both regional and global scales across a wide range of ecosystems, due to the increasing intensity of disturbances and despite conservation efforts [1].Windstorms, wildfires, floods, drought, and insect epidemics are the main natural disturbances in forests [2], creating so-called “early-successional forest ecosystems” (ESFEs) [3]
We studied the nematode communities and microbial characteristics at disturbed and undisturbed sites in deciduous beech forests 12 and 36 months after a windstorm to evaluate (1) whether soil nematode communities and microbial activity were affected by changes in the aboveground ecosystem, (2) relationships between biotic and abiotic soil features, (3) possible mutual links between specific nematode genera and plant species associated with secondary succession of understory vegetation, and (4) selection amongst various parameters that could serve as indicators of changes in soil state throughout forest development
Any disturbance of the soil will lead to a succession in bacteria and fungi and the associated food web, with an initial decrease and an increase in biodiversity [50], in agreement with the authors of Reference [16] who found that the characteristics of microbial activity were significantly lower in the acidic soil of a cleared site of a Lariceto-Piceetum coniferous forest immediately after a windstorm

Summary

Introduction

Windstorms, wildfires, floods, drought, and insect epidemics are the main natural disturbances in forests [2], creating so-called “early-successional forest ecosystems” (ESFEs) [3] The relevance of these disturbances has tended to increase in recent decades because of their increasing occurrence, severity, frequency, and intensity worldwide associated with changes in climate, which are becoming increasingly obvious [4]. Forest sites after severe disturbances are characterized by open environments not dominated by trees, which dramatically alter the site microclimate, including light conditions [3] These changes lead to increased exposure to sunlight, more extreme temperatures (ground and air), higher air velocities, and lower levels of relative humidity and moisture in the litter and surface soil. Shifts in these environmental metrics favor some species but create suboptimal or intolerable conditions for others [3]

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