Effects of wind disturbance and salvage harvesting on ectomycorrhizal and saprotrophic macrofungi in a pine woodland

Abstract

Natural disturbances alter the biophysical conditions of ecosystems, influencing patterns of structure, composition, and successional dynamics. These disturbances often create structural legacies that promote biodiversity and ecosystem function. Following high severity natural disturbance in forest ecosystems, land-managers sometimes employ salvage harvesting to harvest trees killed or damaged by the disturbance agent.

Despite its widespread practice, the effects of salvage harvesting on many ecosystem functions and species assemblages are still poorly understood. This study presents the first attempt to document and analyze the effects of salvage harvesting on macrofungal communities following catastrophic wind disturbance. On 27 April 2011, an EF3 tornado damaged forest stands within the Oakmulgee Ranger District of the Talladega National Forest in west-central Alabama, USA. Following the event, some stands were subject to salvage harvesting. In 2016, I established three treatments, undisturbed, tornado disturbed, and salvage harvested, in stands that were dominated by Pinus palustris P. Miller prior to the 2011 disturbance events. Within each treatment, 20 0.04 ha fixed radius plots were established to collect forest inventory data. Additionally, five 10 x 100 m plots were established in each treatment and inventoried for macrofungal sporocarps between May and November 2016. Throughout the sample period, 546 occurrences of 84 macrofungal species were recorded. Tornado disturbed plots hosted the highest macrofungal species richness overall. Undisturbed plots hosted the highest species richness for ectomycorrhizal macrofungi.

Salvage harvested plots had reduced species richness for both saprotrophic and ectomycorrhizal macrofungi compared to tornado disturbed plots. Non-metric multidimensional scaling ordination and permutational multivariate analysis of variance indicated that all three treatments differed in macrofungal community composition. The results indicated that salvage harvesting following catastrophic wind disturbance has the capacity to reduce macrofungal species richness and fruiting abundance. The reduction in deadwood volume and alterations to the ectomycorrhizal-associating plant community documented at salvage harvested sites is likely responsible for the observed differences in macrofungal fruiting patterns. The implications of reduced macrofungal richness in the early stages of forest development following catastrophic disturbance should be subject to long-term studies.