Effects of Forest Age and Invasive Shrubs on Mycophilous Coleoptera Communities in a Temperate Deciduous Woodland

TL;DR

The study found that invasive shrubs, not forest age, reduce beetle diversity in Midwestern U.S. forests.

Contribution

This paper provides new insights into how invasive species affect detritivore communities in deciduous forests.

Findings

No strong differences in beetle abundance or diversity between young and old forest stands.

Invasive honeysuckle shrubs decreased beetle abundance and diversity.

Beetle communities varied significantly across seasonal sampling periods.

Abstract

Mature, old growth forests are known to harbor distinct plant and animal communities and high biodiversity. However, there has been little study of how detritivore communities vary in diversity and composition between old and young forest stands. To assess how such communities vary with forest age, we compare fungus-associated beetle communities in young and old deciduous woodlands of Southwestern Ohio (U.S.A.) over a growing season. We found no strong differences in abundance or diversity of fungus-associated beetle communities between new and old forest stands, but infestation by invasive honeysuckle shrubs was associated with decreased beetle abundance and diversity. In addition, communities strongly varied across seasonal sampling periods. Our surveys of these fungus-associated beetles represent an initial step toward understanding deciduous forest detritivore communities in the U.S. Midwest and how they are shaped by forest traits. Such information is crucial if we wish to manage forests to enhance biodiversity and ecosystem services.

Forests in the Eastern and Midwestern U.S. have been profoundly affected by human use over the last 150 years, with few old growth forests remaining. Such mature forests may harbor distinct communities and high biodiversity, particularly detritivores and their associated food webs. These communities, however, have been surveyed only rarely in comparisons of diversity and community composition between old and young forests. Here, we compare the mycophilous beetle communities of young and old deciduous forest stands in Southwestern Ohio (U.S.A.). We assess how the abundance and diversity of beetles associated with fungal sporocarps varies with forest age, downed woody debris, and invasive honeysuckle density. We surveyed fungus-associated beetles with baited traps at eight wooded parklands centered around Dayton, Ohio, conducting sampling three times over a growing season. In contrast to expectation, we found no clear effect of forest age on mycophilous beetle communities, but infestation by invasive honeysuckle (Lonicera maackii) negatively affected beetle abundance and diversity. Beetle abundance, richness, and community composition also strongly varied across seasonal sampling periods. Our surveys of mycophilous beetles in a Midwestern U.S. forest represent an initial step toward understanding how these communities are shaped by forest age and invasive species. Such information is crucial in managing forests to preserve biodiversity and ecosystem services.

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