Forest thinning across a forest-meadow ecotone increases light heterogeneity and understory plant diversity

Ecotones, the transitional zones between distinct habitats, are vital for ecosystem functioning. Traditional management practices frequently create abrupt boundaries, leading to stressful conditions for organisms. To address this challenge, a novel land management technique called ‘edge feathering’, which involves gradual thinning of the canopy, has been introduced. This study, conducted at Holden Arboretum in Kirtland, Ohio, investigated the effects of edge feathering on light availability and understory plant diversity in edge feathered and control treatments. Three transects per treatment with 6 plots each were established in a gradient from the forest interior toward the meadow. We calculated the coefficient of variation in light availability as light heterogeneity, and plant diversity indices at the plot level. Edge feathering increased light heterogeneity by more than 2.5 fold (p=0.0001957), species richness by twofold (p less than 0.0001), and both Shannon’s and Simpson’s diversity indices by approximately 1.5-fold (p less than 0.05) compared to the control. These findings demonstrate that higher light heterogeneity is strongly associated with greater understory plant diversity. These effects were observed within just 3.5 years of implementation, underscoring the rapid and measurable benefits of edge feathering.