An Ecological Approach to Riparian-Buffer Definition, and Implications for Timber Harvests in Nova Scotia, Canada

Abstract

Riparian buffers in North America usually have been designed to mitigate specific land-use impacts on watercourses, and thus often fail to preserve the full range of riparian ecological functions (e.g. wildlife habitat). This paper reviews the unique ecological characteristics of riparian areas in an attempt to formulate a widely applicable buffer delineation capable of maintaining most riparian ecosystem services. To avoid ambiguity, the watercourse is defined in terms of its high water mark, which includes flood-prone areas and adjacent wetlands. Published data on the spatial range of riparian functions indicate that the land within 50 m of the water edge interacts the most with the watercourse through exchanges of matter and energy. For maximum effectiveness, the riparian buffer should be continuous (across all types of land use, ownership, and jurisdiction) and its native vegetation preserved or restored. The delineation method has been applied using spatial analysis to a watershed in Nova Scotia, Canada. A 50-m buffer represents 15% of the watershed terrestrial area. Excluding timber harvest in this buffer decreases the total potential harvestable volume by 11% compared to provincial regulations and by 7% compared to the practices of the local forest-products company. The simplicity of the proposed riparian buffer delineation lends itself to easy implementation by any landowner with little training and cost, a distinct advantage considering the urgency of protecting freshwater ecosystems. Moreover, continuous buffers can serve as wildlife movement corridors throughout the watershed and are thus an essential component of connectivity planning at the landscape scale.

Integrated Modeling of Soil Erosion for a Canadian Watershed in Response to Projected Changes in Climate and Consequent Adoption of Mitigating Best Management Practices

“…It is understandable that concerns exist among land-use managers about the extent of resources that might be "locked up" in such buffer strip reserves. However, several Canadian GIS studies have shown that these concerns may be exaggerated, at least for non-mountainous areas [15] [26]. The present study suggests that expanding protective buffer strips from the legal requirement of 30 m to an increased width of 70 m will be needed in order to offset projected increases of 25% in soil erosion due to regional climate change over the next half century.…”

“…Few BMPs deliver more ecosystem goods and services per unit areal coverage than do riparian buffer strips [13] [14], particularly in relation to reducing the transport and deposition of soil to otherwise threatened lakes and rivers, such as those in Canada [10] [26]. In a comprehensive review, Capron et al [27] identify riparian ecosystems as being those landscapes that will be in particular need for adapting human activities in the face of climate change.…”

“…Shading reflects terrain roughness. Journal of Geoscience and Environment Protection adequate to maintain water quality[21] [14][26]. Ontario's recommended guidelines for riparian buffer strip widths (termed "areas of concern") are based on preventing the transport of eroded soil in relation to surface slope: 30 m for slopes < 15%, 50 m for slopes of 16% to 30%, 70 m for slopes of 31% to 45%, and 90 m for slopes > 46%[59] [60].…”

“…Ontario's recommended guidelines for riparian buffer strip widths (termed "areas of concern") are based on preventing the transport of eroded soil in relation to surface slope: 30 m for slopes < 15%, 50 m for slopes of 16% to 30%, 70 m for slopes of 31% to 45%, and 90 m for slopes > 46%[59] [60]. Because differences exist in buffer strip management in terms of recommendations for either consistent[26], or in the case of Ontario, variable, widths, we estimated the influence of buffer strip BMPs (i.e.…”

Delineating and mapping riparian areas for ecosystem service assessment

“…Delineating riparian areas may assist in improving our understanding of how these areas might benefit ecosystem service provision by (a) identifying patterns in land use and their importance in the landscape, (b) characterizing soil types and habitat distributions within the riparian areas, (c) reducing the anthropogenic pressures to which they are subject, (d) preserving their intrinsic value, and (e) establishing a common framework for their classification. Numerous approaches to delineate riparian areas have been undertaken ranging from simplistic models in which a fixed‐width buffer is implemented (Hawes & Smith, ; Stoffyn‐Egli & Duinker, ), to more complex holistic approaches where the most relevant riparian characteristics such as soil properties, associated floodplain extent, vegetation type, or hydrologic parameters are integrated into delineation models of varying complexity. These are subsequently used to generate a variable‐width riparian buffer (Abood & Maclean, ; Baker, Lawrence, Montagne, & Patten, ; Belletti et al, ; Lyons, Görres, & Amador, ; Momm & Bingner, ).…”