Landscape-level stream fragmentation caused by hanging culverts along roads in Alberta’s boreal forest

2008 ◽  
Vol 38 (3) ◽  
pp. 566-575 ◽  
Author(s):  
David Park ◽  
Michael Sullivan ◽  
Erin Bayne ◽  
Garry Scrimgeour
Keyword(s):  
Logistic Regression ◽  
Boreal Forest ◽  
Regulatory Agencies ◽  
Management Approach ◽  
Traditional Management ◽  
Stream Surface ◽  
Boreal Streams ◽  
Road Development ◽  
Stream Fragmentation ◽  
Landscape Level

Hanging culverts (i.e., outfall elevated above the stream surface) can fragment fish communities in streams by creating upstream movement barriers. We conducted a retrospective study of culvert stream crossings along industrial roads in Alberta’s boreal forest to describe factors relating to the occurrence of hanging culverts and to quantify watershed fragmentation. One-half (50%; 187/374) of culverts surveyed in four watersheds during 2002 and 2003 were hanging. Logistic regression showed that the occurrence of a hanging culvert was positively and significantly related to culvert age and reach slope. We quantified fragmentation in the watersheds as the length-based percentage of stream reaches above hanging culverts. In three watersheds, stream fragmentation was approximately 5%, whereas one watershed showed 20% fragmentation. Extrapolating our results to Alberta’s entire boreal forest, we estimated that several thousand hanging culverts were fragmenting tens of thousands of kilometres of streams in 2003. These numbers are likely increasing as a result of continued road development and ageing culverts. We conclude that the traditional management approach of road builders and regulatory agencies has failed to prevent the development of hanging culverts and fragmentation of small boreal streams in Alberta. We provide recommendations for future study and management of this growing problem.

scholarly journals Could increased boreal forest ecosystem productivity offset carbon losses from increased disturbances?

2007 ◽  
Vol 363 (1501) ◽  
pp. 2259-2268 ◽  
Author(s):  
Werner A Kurz ◽  
Graham Stinson ◽  
Greg Rampley
Keyword(s):  
Boreal Forest ◽  
Net Primary Production ◽  
Natural Disturbance ◽  
Climatic Changes ◽  
Forest Sector ◽  
Carbon Budget Model ◽  
C Stocks ◽  
Carbon Losses ◽  
Forest C ◽  
Landscape Level

To understand how boreal forest carbon (C) dynamics might respond to anticipated climatic changes, we must consider two important processes. First, projected climatic changes are expected to increase the frequency of fire and other natural disturbances that would change the forest age-class structure and reduce forest C stocks at the landscape level. Second, global change may result in increased net primary production (NPP). Could higher NPP offset anticipated C losses resulting from increased disturbances? We used the Carbon Budget Model of the Canadian Forest Sector to simulate rate changes in disturbance, growth and decomposition on a hypothetical boreal forest landscape and to explore the impacts of these changes on landscape-level forest C budgets. We found that significant increases in net ecosystem production (NEP) would be required to balance C losses from increased natural disturbance rates. Moreover, increases in NEP would have to be sustained over several decades and be widespread across the landscape. Increased NEP can only be realized when NPP is enhanced relative to heterotrophic respiration. This study indicates that boreal forest C stocks may decline as a result of climate change because it would be difficult for enhanced growth to offset C losses resulting from anticipated increases in disturbances.

Landscape-level variability in the age underestimation of understory black spruce in the northern boreal forest of Quebec

2005 ◽  
Vol 35 (3) ◽  
pp. 633-642 ◽  
Author(s):  
Marc-André Parisien ◽  
Luc Sirois ◽  
Sylvain Parent
Keyword(s):  
Boreal Forest ◽  
Mixed Models ◽  
Black Spruce ◽  
Ground Level ◽  
Simple Linear Regression ◽  
Linear Regression Models ◽  
Growth Rings ◽  
Age Correction ◽  
The Relationship ◽  
Landscape Level

This study examines the variability of the potential aging error for saplings (height ≤1.5 m) of black spruce (Picea mariana (Mill.) B.S.P.) in mature fire-dominated stands (n = 14 stands) of the northern boreal forest of northwestern Quebec. Age underestimation was determined by counting the number of underground bud scars of saplings. The magnitude and variability of age underestimation was compared within and among stands. The relationship between corrected ages (the sum of age underestimation and the number of growth rings at ground level) and ground-level ages was strongly linear and was therefore described with simple linear regression models. To evaluate landscape-level variability in this relationship, the regressions were compared among stands using mixed models. Despite high variability in age underestimation at the stand level, the relationship between corrected and ground-level age was highly significant (p < 0.0001) for all stands except one. However, there were many significant statistical differences between these regressions, indicating high landscape-level variability. The magnitude of age underestimation was found to be highly site specific (means of 7–26 years), the phenomenon being more marked and variable in older stands. Given high landscape-level variability, age underestimation of understory black spruce saplings in northern boreal stands must be documented for every sampled stand to apply a valid age correction in studies that involve multiple stands.

scholarly journals Landscape control of uranium and thorium in boreal streams – spatiotemporal variability and the role of wetlands

2012 ◽  
Vol 9 (3) ◽  
pp. 2823-2849 ◽  
Author(s):  
F. Lidman ◽  
C. M. Mörth ◽  
H. Laudon
Keyword(s):  
Boreal Forest ◽  
Gamma Spectrometry ◽  
Spatiotemporal Variability ◽  
Forest Landscape ◽  
Spatiotemporal Variations ◽  
Forest Region ◽  
Boreal Streams ◽  
Landscape Control ◽  
Boreal Forest Region

Abstract. The concentrations of uranium and thorium in ten partly nested streams in the boreal forest region were monitored over a two-year period. Considerable spatiotemporal variations were observed, with little or no correlation between streams. The export of both uranium and thorium varied substantially between the subcatchments, ranging from 1.7 to 30 g km−2 a−1 for uranium and from 3.2 to 24 g km−2 a−1 for thorium. Airborne gamma spectrometry was used to measure the concentrations of uranium and thorium in surface soils throughout the catchment, but could not explain the variability in the export. Instead, the extent of lakes and mires within each subcatchment was found to be a stronger predictor for the transport of uranium and thorium. The results indicate that there is a predictable and systematic accumulation of both uranium and thorium in boreal mires. Approximately 65–80 % of uranium and 55–65 % of thorium entering a mire is estimated to be retained in the peat. Overall, accumulation in mires and other types of wetlands is estimated to decrease the fluxes of uranium and thorium from the boreal forest landscape by 30–40 %. The atmospheric deposition of uranium and thorium was also quantified and its contribution to boreal streams was found to be low compared to weathering.

scholarly journals Geospatial information on geographical and human factors improved anthropogenic fire occurrence modeling in the Chinese boreal forest

2016 ◽  
Vol 46 (4) ◽  
pp. 582-594 ◽  
Author(s):  
Futao Guo ◽  
Selvaraj Selvalakshmi ◽  
Fangfang Lin ◽  
Guangyu Wang ◽  
Wenhui Wang ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Human Factors ◽  
Boreal Forest ◽  
Forest Fire ◽  
Management Practices ◽  
Explanatory Power ◽  
Driving Factors ◽  
Fire Occurrence ◽  
Geospatial Information ◽  
Anthropogenic Fire

We applied a classic logistic regression (LR) model together with a geographically weighted logistic regression (GWLR) model to determine the relationship between anthropogenic fire occurrence and potential driving factors in the Chinese boreal forest and to test whether the explanatory power of the LR model could be increased by considering geospatial information of geographical and human factors using a GWLR model. Three tests, “all variables”, “significant variables”, and “cross-validation”, were applied to compare model performance between the LR and GWLR models. Our results confirmed the importance of distance to railway, elevation, length of fire line, and vegetation cover on fire occurrence in the Chinese boreal forest. In addition, the GWLR model performs better than the LR model in terms of model prediction accuracy, model residual reduction, and spatial parameter estimation by considering geospatial information of explanatory variables. This indicates that the global LR model is incapable of identifying underlying causal factors for wildfire modeling sufficiently. The GWLR model helped identify spatial variation between driving factors and fire occurrence, which can contribute better understanding of forest fire occurrence over large geographic areas and the forest fire management practices may be improved based on it.

Old growth in the boreal forest: A dynamic perspective at the stand and landscape level

2003 ◽  
Vol 11 (S1) ◽  
pp. S99-S114 ◽  
Author(s):  
Daniel Kneeshaw ◽  
Sylvie Gauthier
Keyword(s):  
Boreal Forest ◽  
Old Growth ◽  
Dynamic Perspective ◽  
Landscape Level

scholarly journals Modeling Anthropogenic Fire Occurrence in the Boreal Forest of China Using Logistic Regression and Random Forests

Forests ◽  
2016 ◽  
Vol 7 (12) ◽  
pp. 250 ◽  
Author(s):  
Futao Guo ◽  
Lianjun Zhang ◽  
Sen Jin ◽  
Mulualem Tigabu ◽  
Zhangwen Su ◽  
...  
Keyword(s):  
Logistic Regression ◽  
Boreal Forest ◽  
Random Forests ◽  
Fire Occurrence ◽  
Anthropogenic Fire

Cost-effective strategies to conserve boreal forest biodiversity and long-term landscape-level maintenance of habitats

2010 ◽  
Vol 130 (5) ◽  
pp. 717-727 ◽  
Author(s):  
Mikko Mönkkönen ◽  
Pasi Reunanen ◽  
Janne S. Kotiaho ◽  
Artti Juutinen ◽  
Olli-Pekka Tikkanen ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Cost Effective ◽  
Forest Biodiversity ◽  
Effective Strategies ◽  
Landscape Level

scholarly journals Landscape control of uranium and thorium in boreal streams – spatiotemporal variability and the role of wetlands

2012 ◽  
Vol 9 (11) ◽  
pp. 4773-4785 ◽  
Author(s):  
F. Lidman ◽  
C. M. Mörth ◽  
H. Laudon
Keyword(s):  
Boreal Forest ◽  
Stream Water ◽  
Spatiotemporal Variability ◽  
Forest Landscape ◽  
Order Stream ◽  
Forest Region ◽  
Boreal Streams ◽  
Wide Range ◽  
Hydrogen Carbonate ◽  
Mineral Soils

Abstract. The concentrations of uranium and thorium in ten partly nested streams in the boreal forest region were monitored over a two-year period. The investigated catchments ranged from small headwaters (0.1 km2) up to a fourth-order stream (67 km2). Considerable spatiotemporal variations were observed, with little or no correlation between streams. The fluxes of both uranium and thorium varied substantially between the subcatchments, ranging from 1.7 to 30 g km−2 a−1 for uranium and from 3.2 to 24 g km−2 a−1 for thorium. Airborne gamma spectrometry was used to measure the concentrations of uranium and thorium in surface soils throughout the catchment, suggesting that the concentrations of uranium and thorium in mineral soils are similar throughout the catchment. The fluxes of uranium and thorium were compared to a wide range of parameters characterising the investigated catchments and the chemistry of the stream water, e.g. soil concentrations of these elements, pH, TOC (total organic carbon), Al, Si and hydrogen carbonate, but it was concluded that the spatial variabilities in the fluxes of both uranium and thorium mainly were controlled by wetlands. The results indicate that there is a predictable and systematic accumulation of both uranium and thorium in boreal wetlands that is large enough to control the transport of these elements. On the landscape scale approximately 65–80% of uranium and 55–65% of thorium entering a wetland were estimated to be retained in the peat. Overall, accumulation in mires and other types of wetlands was estimated to decrease the fluxes of uranium and thorium from the boreal forest landscape by 30–40%, indicating that wetlands play an important role for the biogeochemical cycling of uranium and thorium in the boreal forest landscape. The atmospheric deposition of uranium and thorium was also quantified, and its contribution to boreal streams was found to be low compared to weathering.

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