Saproxylic beetles' morphological traits and higher trophic guilds indicate boreal forest naturalness

Area of Science:

• Ecology
• Conservation Biology
• Forestry

Background:

• Forests provide critical ecosystem services and harbor significant biodiversity.
• Anthropogenic activities negatively impact forest ecosystems.
• Near-natural forests, characterized by old-growth traits, support distinct species assemblages compared to managed forests.

Purpose of the Study:

• To determine differences in beetle community composition between near-natural and managed forests.
• To identify biodiversity measures that best indicate forest naturalness.
• To evaluate the conservation value of near-natural forests.

Main Methods:

• Utilized a large dataset of 339 obligate saproxylic beetle species collected over a decade in southern Norway's boreal region.
• Employed ordination techniques to analyze differences in community composition between forest types.
• Tested various biodiversity metrics, including species richness and trait-based measures, for their predictive power of forest naturalness.

Main Results:

• A significant difference in beetle community composition was observed between near-natural and managed forests.
• Proportional abundance of predators, community weighted mean (CWM) of wing length, and CWM of body roundness were the most predictive indicators of forest naturalness.
• Higher species richness in near-natural forests was not statistically significant.

Conclusions:

• Near-natural forests possess significant conservation value due to their unique biodiversity.
• Trait-based biodiversity measures offer a more sensitive assessment of forest quality and naturalness than species richness.
• Findings support the use of specific biodiversity metrics for evaluating forest management strategies and conservation efforts.