Anthropogenic Disturbances Create a New Vegetation Toposequence in the Gatineau River Valley, Quebec

Jason Laflamme,Pierre Grondin,Alison Munson,Dominique Arseneault

doi:10.3390/f7110254

Abstract

This study measured changes in forest composition that have occurred since the preindustrial era along the toposequence of the Gatineau River Valley, Quebec, Canada (5650 km2), based on survey records prior to colonization (1804–1864) and recent forest inventories (1982–2006). Changes in forest cover composition over time were found to be specific to toposequence position. Maple and red oak are now more frequent on upper toposequence positions (+26%, +21%, respectively), whereas yellow birch, eastern hemlock, and American beech declined markedly (−34% to −17%). Poplar is more frequent throughout the landscape, but particularly on mid-toposequence positions (+40%). In contrast, white pine, frequent on all toposequence positions in the preindustrial forest, is now confined to shallow and coarse-textured soils (−20%). The preindustrial forest types of the study area were mostly dominated by maple, yellow birch, and beech, with strong components of white pine, hemlock, and eastern white cedar, either as dominant or codominant species. In a context of ongoing anthropogenic disturbances and environmental changes, it is probably not possible to restore many of these types, except where targeted silvicultural interventions could increase the presence of certain species. The new forest types observed should be managed to ensure continuity of vital ecosystem services and functions as disturbance regimes evolve.

Highlights

For the last several centuries, the vast forests of northeastern North America have been subjected to anthropogenic presence and associated disturbances [1,2]
Ourharvesting hypothesis is that species, major anthropogenic disturbances, such selective harvesting of specific fires, agriculture, and exotic pathogens are all important factors that contributed to the present species,caused chronic silvicultural practices such as single-tree selection, human-caused fires, agriculture, state of the forest in this region
The forest resembled the maple–yellow birch–beech forest described in retrospective studies of the northeastern US landscape

Summary

Introduction

For the last several centuries, the vast forests of northeastern North America have been subjected to anthropogenic presence and associated disturbances (land clearing, selective and intensive harvest) [1,2]. Several landscape-scale studies have compared the information contained in these land survey archives to recent forest inventories in order to quantify compositional changes in the forests of northeastern America that have occurred since settlement [2,11,12]. These studies have demonstrated a decrease of coniferous in favor of deciduous species, especially early-successional shade-intolerant species such as poplar (Populus spp.) and white birch (Betula papyrifera Marsh.) [8,13,14].

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