Biological legacies buffer local species extinction after logging

Area of Science:

• Forestry and Conservation Science
• Ecology and Biodiversity Studies
• Bryophyte and Lichen Taxonomy

Background:

• Clearcutting poses a significant threat to forest biodiversity.
• Retention forestry, involving the preservation of living and dead trees, is an emerging alternative to mitigate logging impacts.
• Systematic before-after control-impact studies are crucial for assessing the efficacy of retention practices.

Purpose of the Study:

• To evaluate the survival of logging-sensitive and red-listed bryophytes and lichens after clearcutting with retention.
• To assess the role of retained trees and patches as refugia for these species.
• To identify factors influencing species survival in post-logging environments.

Main Methods:

• Conducted a large-scale survey of bryophyte and lichen occurrences before and after clearcutting with retention.
• Employed a novel methodology for location-specific substrate monitoring.
• Utilized uncut stands as controls to evaluate species response to disturbance.

Main Results:

• Retained living and dead trees served as crucial refugia, enabling the survival of sensitive species for 3-7 years post-logging.
• Species persistence on retained structures varied from 35% to 92%, depending on retention type and organism group.
• Larger pre-harvest bryophyte populations on dead wood significantly increased survival probability, buffering logging effects.

Conclusions:

• Spatial planning of retention structures is essential for supporting logging-sensitive species.
• Retention patches demonstrated higher species persistence for bryophytes and lichens compared to solitary trees or open clearcut areas.
• Moving old logs into retention patches can enhance habitat for dead wood-dependent species, underscoring the need for further before-after control-impact research in retention forestry.