Forest recovery patterns in response to divergent disturbance regimes in the Border Lakes region of Minnesota (USA) and Ontario (Canada)

Abstract

a b s t r a c tThe persistence of landscape-scale disturbance legacies in forested ecosystems depends in part on the nature and strength of feedback among disturbances, their effects, and subsequent recovery processes such as tree regeneration and canopy closure. We investigated factors affecting forest recovery rates over a 25-year time period in a large (6 million ha) landscape where geopolitical boundaries have resulted in important land management legacies (managed forests of Minnesota, USA; managed forests of Ontario, Canada; and a large unmanaged wilderness). Stand-replacing disturbance regimes were quantified across management zones, both inside and outside a central ecoregion, using a time series of classified land cover data constructed at 5-year intervals between 1975 and 2000. The temporally variable disturbance regime of the wilderness was characterized by fine-scaled canopy disturbances punctuated by less frequent large disturbance events (i.e., fire and blow down). The comparably consistent disturbance regimes of the managed forests of Minnesota and Ontario differed primarily in the size distribution of disturbances -principally clearcut harvesting. Using logistic regression we found that a combination of time since disturbance, mapped disturbance attributes, climate, and differences among management zones affected pixel-scale probabilities of forest recovery that reflect recovery rates. We conclude that the magnitude of divergence in landscape disturbance legacies of this region will be additionally reinforced by regional variations in the human and natural disturbance regimes and their interactions with forest recovery processes. Our analyses compliment traditional plot-scale studies that investigate post-disturbance recovery by (a) examining vegetation trends across a wide range of variability and (b) quantifying the cumulative effects of disturbances as they affect recovery rates over a broad spatial extent. Our findings therefore have implications for sustainable forestry, ecosystem-based management, and landscape disturbance and succession modeling.Published by Elsevier B.V.

Is initial post‐disturbance regeneration indicative of longer‐term trajectories?

“…The role of legacies is critical to the trajectory of ecosystem processes and should receive special attention as management strategies are developed (Grumbine , Buma and Wessman , Sturtevant et al. ). Considering that all stands in this study were >120 yr old in the late 20th century, the presence of understory juveniles would be expected.…”

Influence of landscape, habitat, and species co-occurrence on occupancy dynamics of Canada Warblers

“…Extensive changes in habitats and landscapes are occurring in the central and northern portions of the Canada Warbler's breeding range, due to climate change, forest management, and agricultural and residential development (Mladenoff et al 1997, Wolter and White 2002, Frelich and Reich 2009, Galatowitsch et al 2009, Wells 2011, Sturtevant et al 2014). These widespread changes signal the need for urgent conservation action for this species.…”

Disturbance interactions: characterization, prediction, and the potential for cascading effects

“…Compound disturbances may homogenize neighboring patches (e.g., Brown and Johnstone 2012). At the landscape scale, however, those small homogenous patches may increase heterogeneity in cover types (Buma and Wessman 2012), and the spatial patterns resulting from those interactions may themselves constitute a mechanism for interaction with future disturbances (Sturtevant et al 2014). For example, spatially mediated interactions between fire resilience, species level flammability, and fire spread may drive smaller fire extents in Alaskan boreal forests relative to climate projections which do not consider spatial legacies (Johnstone et al 2011), and the effects of spatial configuration and interactions between repeat fires has been proposed as a mechanism for the maintenance of forest-savannah systems (Schertzer et al 2015).…”