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Research article - Peer-reviewed, 2016

Factors driving structure of natural and anthropogenic forest edges from temperate to boreal ecosystems

Esseen, Per-Anders; Hedström Ringvall, Anna; Harper, Karen Amanda; Christensen, Pernilla; Svensson, Johan

Abstract

QuestionsWhat factors control broad-scale variation in edge length and three-dimensional boundary structure for a large region extending across two biomes? What is the difference in structure between natural and anthropogenic edges?LocationTemperate and boreal forests across all of Sweden, spanning latitudes 55-69 degrees N.MethodsWe sampled more than 2000 forest edges using line intersect sampling in a monitoring programme (National Inventory of Landscapes in Sweden). We compared edge length, ecosystem attributes (width of adjacent ecosystem, canopy cover, canopy height, patch contrast in canopy height, forest type) and boundary attributes (profile, abruptness, shape) of natural edges (lakeshore, wetland) with anthropogenic edges (clear-cut, agricultural, linear disturbance) in five regions.ResultsAnthropogenic edges were nearly twice as abundant as natural edges. Length of anthropogenic edges was largest in southern regions, while the abundance of natural edges increased towards the north. Edge types displayed unique spectrums of boundary structures, but abrupt edges dominated, constituting 72% of edge length. Anthropogenic edges were more abrupt than natural edges; wetland edges had the most gradual and sinuous boundaries. Canopy cover, canopy height, patch contrast and forest type depended on region, whereas overall boundary abruptness and shape showed no regional pattern. Patch contrast was related to temperature sum (degree days5 degrees C), suggesting that regional variability can be predicted from climate-controlled forest productivity. Boundary abruptness was coupled with the underlying environmental gradient, land use and forest type, with higher variability in deciduous than in conifer forest.ConclusionsEdge origin, land use, climate and tree species are main drivers of broad-scale variability in forest edge structure. Our findings have important implications for developing ecological theory that can explain and predict how different factors affect forest edge structure, and help to understand how land use and climate change affect biodiversity at forest edges.

Keywords

Agricultural edge; Boundary abruptness; Clear-cut edge; Climate; Edge influence; Edge length; Lakeshore edge; Land use; Linear disturbance edge; Patch contrast; Tree species; Wetland edge

Published in

Journal of Vegetation Science
2016, Volume: 27, number: 3, pages: 482-492