Comparing soil biogeochemical processes in novel and natural boreal forest ecosystems

Abstract

Emulating the variability that exists in the natural landscape prior to disturbance should be a goal of soil reconstruction and land reclamation efforts following resource extraction. Long-term ecosystem sustainability within reclaimed landscapes can only be achieved with the re-establishment of biogeochemical processes between reconstructed soils and plants. In this study, we assessed key soil biogeochemical attributes (nutrient availability, organic matter composition, and microbial communities) in reconstructed, novel, anthropogenic ecosystems, covering different reclamation treatments following open-cast mining for oil extraction. We compared the attributes to those present in a range of natural soils representative of mature boreal forest ecosystems in the same area of Northern Alberta. Soil nutrient availability was determined in situ with resin probes, organic matter composition was described with ¹³C nuclear magnetic resonance spectroscopy and soil microbial community structure was characterized using phospholipid fatty acid analysis. Significant differences among natural ecosystems were apparent in nutrient availability and seemed more related to the dominant tree cover than to soil type. When analyzed together, all natural forests differed significantly from the novel ecosystems, in particular with respect to soil organic matter composition. However, there was some overlap between the reconstructed soils and some of the natural ecosystems in nutrient availability and microbial communities, but not in organic matter characteristics. Hence, our results illustrate the importance of considering the range of natural landscape variability and including several soil biogeochemical attributes when comparing novel, anthropogenic ecosystems to the mature ecosystems that constitute ecological targets

Plant Community and Nitrogen Deposition as Drivers of Alpha and Beta Diversities of Prokaryotes in Reconstructed Oil Sand Soils and Natural Boreal Forest Soils

“…Forest floor depth, pH, and abundance of trees and shrubs, P. banksiana (Ͻ5 m), and Viburnum edule further added to the already contributing nitrogen deposition, clay content and abundance of P. juniperinum variables [F (7,12) ϭ 2.790; P ϭ 0.001] (Fig. 6A).…”

“…Alone, the abundance of P. banksiana (Ͻ5 m; only present in natural sites), P. juniperinum (only present in two of the 15 reconstructed sites), and V. edule explained 6.2% of the variation [F (3,12) ϭ 1.563; P ϭ 0.03]; nitrogen deposition, soil clay content, soil pH, and forest floor depth explained 9% of the same variation [F (4,12) ϭ 1.650; P ϭ 0.007]. Jointly, these variables explained 29.4% of the variation in prokaryotic microbial communities at the class level [F (7,12) ϭ 3.186; P ϭ 0.001] (Fig. 6B).…”

“…As such, it is unlikely that these reconstructed forest soils will exactly mirror preexisting boreal forest soils, and novel soil ecosystems (10,11) will most probably arise from the reconstruction efforts. Soil restoration efforts aiming at reestablishing soil functions, and chiefly nutrient cycling, rather than simply trying to replicate structural qualities of the previous soil ecosystem are seen as key to ensuring the long-term sustainability of reclaimed boreal forest landscapes (12).…”

Carbon, nitrogen and phosphorus release from peat and forest floor-based cover soils used during oil sands reclamation

“…Consequently, when reconstructing coarse-textured soils following land disturbance, it is essential that the right amount and the right type of organic matter amendment be used (Larney and Angers 2012). Furthermore, monitoring how organic matter evolves and releases nutrients in reconstructed soils is key to understanding if, and how quickly, sustainable processes and functions can be restored in these soils (Quideau et al 2013b;Macdonald et al 2015).…”

Stumping trials in British Columbia — organic matter removal and compaction effects on tree growth from seedlings to midrotation stands

“…Disturbance events, e.g., wind or fire, add large quantities of organic matter (via tree trunks and root systems) to the soil in decadal to centennial pulse events. Comparing the historical natural disturbance mechanisms with the effects of anthropogenic disturbance (e.g., harvesting, mining, or biomass removal for biofuel) on forest soil quality and forest productivity has been the subject of much research and review (Johnson and Curtis 2001;Powers et al 2005;Quideau et al 2013;Thiffault et al 2011;Walmsley and Godbold 2010). However, due to the relatively recent nature of anthropogenic disturbance and the monitoring of its impacts, the long-term effects on forest soils have been difficult to ascertain.…”