Comparative impacts of fire and forest harvesting on water quality in Boreal Shield lakes

2000 ◽  
Vol 57 (S2) ◽  
pp. 105-117 ◽  
Author(s):  
Richard Carignan ◽  
Pierre D'Arcy ◽  
Sébastien Lamontagne
Keyword(s):  
Water Quality ◽  
Organic Nitrogen ◽  
Light Attenuation ◽  
Forest Harvesting ◽  
Total Organic Nitrogen ◽  
Simultaneous Impact ◽  
Boreal Shield ◽  
Clearcut Logging ◽  
Mobile Ions ◽  
Shield Lakes

Water quality was monitored in Boreal Shield lakes for 3 years following their simultaneous impact by clearcut logging or wildfire. Seventeen similar undisturbed lakes served as references. Dissolved organic carbon (DOC) and the light attenuation coefficient (εPAR) were up to threefold higher in cut lakes than in reference and burnt lakes. Compared with median values for reference lakes, cut and burnt lakes had higher concentrations of total phosphorus (TP) (two- to three-fold), total organic nitrogen (TON) (twofold), and K+, Cl-, and Ca2+ (up to sixfold). NO3- and SO42- concentrations were up to 60- and 6-fold higher, respectively, in burnt lakes than in reference and cut lakes. In most cases, impacts were directly proportional to the area harvested or burnt divided by the lake's volume or area. These simple models correctly predicted the changes observed in three lakes harvested during the study. Some of the ob served effects occur on different time scales. Mobile ions released by fire (K+, Cl-, SO42-, NO3-) or harvesting (K+, Cl-, some DOC) are rapidly flushed out of the watershed (50% decrease in 3 years). Other constituents or properties (TP, TON, DOC, εPAR, Ca2+, Mg2+) show little change or are still increasing after 3 years and will take a longer time to reach normal levels.

scholarly journals Impact of forest harvesting on water quality and fluorescence characteristics of dissolved organic matter in eastern Canadian Boreal Shield lakes in summer

2015 ◽  
Vol 12 (23) ◽  
pp. 6999-7011 ◽  
Author(s):  
P. Glaz ◽  
J.-P. Gagné ◽  
P. Archambault ◽  
P. Sirois ◽  
C. Nozais
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Forest Harvesting ◽  
Spectroscopic Techniques ◽  
Clear Cutting ◽  
Fluorescence Measurements ◽  
Fluorescence Characteristics ◽  
Boreal Shield ◽  
Shield Lakes

Abstract. Forestry activities in the Canadian Boreal region have increased in the last decades, raising concerns about their potential impact on aquatic ecosystems. Water quality and fluorescence characteristics of dissolved organic matter (DOM) were measured over a 3-year period in eight eastern Boreal Shield lakes: four lakes were studied before, 1 and 2 years after forest harvesting (perturbed lakes) and compared with four undisturbed reference lakes (unperturbed lakes) sampled at the same time. ANOVAs showed a significant increase in total phosphorus (TP) in perturbed lakes when the three sampling dates were considered and in DOC concentrations when considering 1 year before and 1 year after the perturbation only. At 1 year post-clear cutting DOC concentrations were about 15 % greater in the perturbed lakes at ~ 15 mgC L−1 compared to 12.5 mgC L−1 in the unperturbed lakes. In contrast, absorbance and fluorescence measurements showed that all metrics remained within narrow ranges compared to the range observed in natural waters, indicating that forest harvesting did not affect the nature of DOM characterized with spectroscopic techniques. These results confirm an impact of forestry activities 1 year after the perturbation. However, this effect seems to be mitigated 2 years after, indicating that the system shows high resilience and may be able to return to its original condition in terms of water quality parameters assessed in this study.

scholarly journals Impact of forest harvesting on water quality and fluorescence characteristics of dissolved organic matter in Eastern Canadian Boreal Shield lakes

2015 ◽  
Vol 12 (12) ◽  
pp. 9307-9339 ◽  
Author(s):  
P. Glaz ◽  
J.-P. Gagné ◽  
P. Archambault ◽  
P. Sirois ◽  
C. Nozais
Keyword(s):  
Water Quality ◽  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Forest Harvesting ◽  
Clear Cutting ◽  
Fluorescence Measurements ◽  
Fluorescence Characteristics ◽  
Boreal Shield ◽  
One Year ◽  
Shield Lakes

Abstract. Forestry activities in the Canadian Boreal region have increased in the last decades, raising concerns about their potential impact on aquatic ecosystems. Water quality and fluorescence characteristics of dissolved organic matter (DOM) were measured over a three-year period in eight Eastern Boreal Shield lakes: four lakes were studied before, one and two years after forest harvesting (perturbed lakes) and compared with four undisturbed reference lakes (unperturbed lakes) sampled at the same time. ANOVAs showed a significant increase in total phosphorus (TP) in perturbed lakes when the three sampling dates were considered and in DOC concentrations when considering one year before and one year after the perturbation only. At one year post-clear cutting DOC concentrations were about 15 % greater in the perturbed lakes at ~15 mg C L−1 compared to 12.5 mg C L−1 in the unperturbed lakes. In contrast, absorbance and fluorescence measurements showed that all metrics remained within narrow ranges compared to the range observed in natural waters, indicating that forest harvesting did not affect the nature of DOM characterised with spectroscopic techniques. Multivariate statistical analysis showed lakes to be significantly different one year after the perturbation. These results confirm an impact of forestry activities one year after the perturbation. However, this effect seems to be mitigated two years after, indicating that the system shows high resilience and may be able to return to its original condition.

Pelagic and benthic algal responses in eastern Canadian Boreal Shield lakes following harvesting and wildfires

2000 ◽  
Vol 57 (S2) ◽  
pp. 136-145 ◽  
Author(s):  
Dolors Planas ◽  
Mélanie Desrosiers ◽  
S-Raphaëlle Groulx ◽  
Serge Paquet ◽  
Richard Carignan
Keyword(s):  
Repeated Measures ◽  
Algal Biomass ◽  
Forest Harvesting ◽  
Algal Community ◽  
Significant Treatment ◽  
Repeated Measures Anova ◽  
Chl A ◽  
Boreal Shield ◽  
Shield Lakes ◽  
Reference Lakes

Pelagic and benthic algal biomass and pelagic algal community structure were measured in Boreal Shield lakes impacted by forest harvesting and wildfires (Haute-Mauricie, Québec). Sixteen reference lakes in which the watershed has been unperturbed for at least 40 years, seven harvested lake watersheds (logged in 1995), and nine lake watersheds burnt in 1995 were sampled for 3 years following harvesting or wildfires. From 1996 to 1998, repeated-measures ANOVA showed significant effects between treatment and sampling years for pelagic chlorophyll a (Chl a) and biomass, but for 1997-1998 benthic Chl a, repeated-measures ANOVA showed only significant treatment effects. Chl a concentrations increased 1.4- to 3-fold in perturbed lakes as compared with reference lakes. Areal pelagic Chl a (milligrams per square metre) was lower than estimated littoral Chl a in perturbed lakes. The pelagic algal community was dominated by mixotrophic nanoflagellates in reference lakes. Watershed perturbation induced differential changes in pelagic algal communities: mixotrophic nanoflagellates increased in harvested lakes and photoautotrophic diatoms in burnt lakes. Considering only perturbed lakes, algal biomass was proportional to the fraction of the catchment area perturbed divided by the surface area of lakes in the catchment.

Effects of experimental clearcut logging on water quality in three small boreal forest lake trout (Salvelinus namaycush) lakes

2000 ◽  
Vol 57 (S2) ◽  
pp. 92-96 ◽  
Author(s):  
Robert J Steedman
Keyword(s):  
Water Quality ◽  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
First Year ◽  
Forest Lake ◽  
Clearcut Logging ◽  
Quality Response ◽  
Shield Lakes

Water quality was monitored in three 30-ha stratified headwater Precambrian Shield lakes for 5 years before and 3 years after moderate to extensive catchment deforestation. These lakes, which had water renewal times of about a decade, showed only minor changes in water quality by the third year after logging. Water quality response in a lake with moderate deforestation and intact shoreline forest was similar to that in two lakes with extensive upland and shoreline deforestation. By the second and third years after logging, May-September average volume-weighted concentrations of dissolved organic carbon, chlorophyll, total nitrogen, K+, Cl-, and Si had all increased, generally by about 10-40% over predisturbance levels, while Ca2+ and Mg2+ had declined by 10-25%. Dry weather the first year after logging was associated with temporary declines of 10-20% in dissolved organic carbon and chlorophyll.

scholarly journals Effects of Climate, Limnological Features and Watershed Clearcut Logging on Long-Term Variation in Zooplankton Communities of Boreal Shield Lakes

Water ◽  
2017 ◽  
Vol 9 (10) ◽  
pp. 733 ◽  
Author(s):  
David Lévesque ◽  
Bernadette Pinel-Alloul ◽  
Ginette Méthot ◽  
Robert Steedman
Keyword(s):  
Term Variation ◽  
Boreal Shield ◽  
Clearcut Logging ◽  
Zooplankton Communities ◽  
Shield Lakes

Seagrass depth range and water quality in southern Moreton Bay, Queensland, Australia

1996 ◽  
Vol 47 (6) ◽  
pp. 763 ◽  
Author(s):  
EG Abal ◽  
WC Dennison
Keyword(s):  
Water Quality ◽  
Chlorophyll A ◽  
Suspended Solids ◽  
Light Attenuation ◽  
River Mouth ◽  
Total Suspended Solids ◽  
Quality Parameters ◽  
Depth Range ◽  
Moreton Bay ◽  
A Site

Correlations between water quality parameters and seagrass depth penetration were developed for use as a biological indicator of integrated light availability and long-term trends in water quality. A year-long water quality monitoring programme in Moreton Bay was coupled with a series of seagrass depth transects. A strong gradient between the western (landward) and eastern (seaward) portions of Moreton Bay was observed in both water quality and seagrass depth range. Higher concentrations of chlorophyll a, total suspended solids, dissolved and total nutrients, and light attenuation coefficients in the water column and correspondingly shallower depth limits of the seagrass Zostera capricorni were observed in the western portions of the bay. Relatively high correlation coefficient values (r2 > 0.8) were observed between light attenuation coefficient, total suspended solids, chlorophyll a, total Kjeldahl nitrogen and Zostera capricorni depth range. Low correlation coefficient values (r2 < 0.8) between seagrass depth range and dissolved inorganic nutrients were observed. Seagrasses had disappeared over a five-year period near the mouth of the Logan River, a turbid river with increased land use in its watershed. At a site 9 km from the river mouth, a significant decrease in seagrass depth range corresponded to higher light attenuation, chlorophyll a, total suspended solids and total nitrogen content relative to a site 21 km from the river mouth. Seagrass depth penetration thus appears to be a sensitive bio-indicator of some water quality parameters, with application for water quality management.

scholarly journals Natural stochasticity vs. management effort: use of year-to-year variance for disentangling significance of two mutually confounding factors affecting water quality of a Norwegian cold dimictic lake

2014 ◽  
Vol 11 (11) ◽  
pp. 12489-12518
Author(s):  
A. T. Romarheim ◽  
K. Tominaga ◽  
G. Riise ◽  
T. Andersen
Keyword(s):  
Water Quality ◽  
Lake Water ◽  
Phytoplankton Biomass ◽  
Light Attenuation ◽  
System Structure ◽  
Confounding Factors ◽  
Lake Water Quality ◽  
Management Effort ◽  
Stochastic Event

Natural stochasticity can pose challenges in managing the quality of the environment, or hinder understanding of the system structure. It is problematic because unfavourable stochastic event cancels the costly management effort and because favourable stochastic event overestimates success of the management effort. This paper presents a variance-based modelling method that can be used to quantify the extent to which the natural stochasticity can affect the target environment. We use a case study of a lake water quality assessment in a Norwegian lake of Årungen, together with a lake model MyLake, in order to present the method, and how this method could assist in answering scientific and managerial questions. Specifically, the case study's goal was to disentangle the respective significance of nutrient loading (management) and weather (the confounding natural stochasticity). Many scientifically and managerially relevant understandings have been revealed. For example, variation in runoff volume was most prevalent during autumn and winter, while variation in phosphorus inflow was most extensive from late winter to early spring. Thermal related properties in the lake were mostly determined by weather conditions, whereas loading was the most important factor for phytoplankton biomass and water transparency. Mild winters and greater inputs of suspended matter and phosphorus were followed by increased phytoplankton biomass and light attenuation. These findings suggest also that future changes in the global climate may have important implications for local water management decision-making. The present method of disentangling mutually confounding factors is not limited to lake water quality studies and therefore should provide certain utility in other application field of modelling.

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