Journal articles: 'Stream ecology – Ontario'

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Dolinsek, Ivan J., Robert L. McLaughlin, James W. A. Grant, Lisa M. O’Connor, and Thomas C. Pratt. "Do natural history data predict the movement ecology of fishes in Lake Ontario streams?" Canadian Journal of Fisheries and Aquatic Sciences 71, no. 8 (August 2014): 1171–85. http://dx.doi.org/10.1139/cjfas-2013-0294.

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Little is known about the movements of most stream fishes, so fisheries managers often rely on natural history data from the literature to make management decisions. Observations of over 15 000 individuals from 37 species across 3 years were used to evaluate four aspects of the reliability of literature data for predicting the movement behaviour of stream fishes: (i) water temperature when fish enter streams; (ii) reasons for moving into the streams; (iii) stream residence times of migrants; and (iv) relative use of lake and stream habitats. Comparisons of our data for arrival times in the streams, water temperature at arrival, and time spent in the streams were highly correlated with literature data, whereas relative use of the lake was not. Further, our detailed data revealed two novel findings: (1) in many species juveniles were also moving into streams, even in those species where adults were clearly spawning in the streams; and (2) adult-sized individuals were moving into streams for nonreproductive purposes. Our results suggest that fishery managers can confidently use natural history information to gain general insights into the movement ecology of fishes, but should also recognize that this information remains incomplete in important ways.

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Mahon, Robin, and Eugene K. Balon. "Fish Production in Warmwater Streams in Poland and Ontario." Canadian Journal of Fisheries and Aquatic Sciences 42, no. 6 (June 1, 1985): 1211–15. http://dx.doi.org/10.1139/f85-148.

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Density (numbers per hectare), biomass (kilograms per hectare), and annual production (kilograms per hectare per year) of entire stream fish taxocenes were significantly higher at localities in Ontario (n = 11) than in Poland (n = 14). The production/biomass ratio and the mean size of individuals did not differ significantly between the two sets of localities. The average stream size at the localities studied in Poland was significantly smaller than in Ontario. Production and biomass in Poland showed a significant negative association with stream size, whereas in Ontario these relationships were not significant; therefore, the differences in these variables between Poland and Ontario may even be underestimated. Differences in fluvial fish taxocene richness might explain the observed differences in production if the streams in Poland are less saturated than those in Ontario. However, the possibility of more basic differences in productivity at lower trophic levels cannot be ruled out.

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Raney, Shanel M., and M. Catherine Eimers. "Unexpected declines in stream phosphorus concentrations across southern Ontario." Canadian Journal of Fisheries and Aquatic Sciences 71, no. 3 (March 2014): 337–42. http://dx.doi.org/10.1139/cjfas-2013-0300.

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Long-term trends (1975–2010) in total phosphorus (TP) concentrations were evaluated at 113 stream stations across southern Ontario. Declines in TP were evident at the majority of sites (68%), including those both with (n = 49) and without (n = 64) upstream municipal wastewater treatment plants (MWWTP). Although declines in TP at stream stations downstream of MWWTPs may be attributed to improvements in P removal from treated effluent, declines at the remaining streams must be attributed to other causes. During the same time period, increases in chloride (Cl−) were observed at almost all (95%) of the 64 MWWTP-free stations. Over the past 35 years, urban land cover has increased at the expense of agricultural land area in Ontario, with the majority of these changes occurring in southern Ontario. The coincidence of declines in TP and increases in Cl− at the 64 MWWTP-free streams suggests that the two may be related, with P-rich agricultural fields being replaced with impervious surfaces and therefore increased road salt applications.

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Rand, Peter S., Charles A. S. Hall, William H. McDowell, Neil H. Ringler, and Jonathan G. Kennen. "Factors Limiting Primary Productivity in Lake Ontario Tributaries Receiving Salmon Migrations." Canadian Journal of Fisheries and Aquatic Sciences 49, no. 11 (November 1, 1992): 2377–85. http://dx.doi.org/10.1139/f92-262.

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Many tributary streams of Lake Ontario have become important spawning habitats for introduced Pacific salmon. We examine how phosphorus released through salmon decomposition and other environmental factors potentially limit primary productivity in two Lake Ontario tributaries in New York State. Contribution of phosphorus (measured as total phosphorus) from salmon carcasses, computed as the percentage of the estimated phosphorus discharged from the stream, was very low (< 1%∙yr−1), but of modest importance (> 50%∙d−1) during restricted periods in the spring. Experimental results from three stream sites demonstrated that phosphorus, which is present naturally at high concentrations, is not limiting primary productivity during the period that the salmon are in the streams. Finally, results from an analysis of 15 free-water oxygen studies indicate that the streams are productive (gross primary production 0.9–10.2 g O2∙m−2∙d−1) and that light appears to limit stream primary productivity more than nutrients. We conclude that salmon migrations are unlikely to substantially increase the rate of primary productivity in these already fertile streams.

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Giberson, Donna J., and Rosemary J. Mackay. "Life history and distribution of mayflies (Ephemeroptera) in some acid streams in south central Ontario, Canada." Canadian Journal of Zoology 69, no. 4 (April 1, 1991): 899–910. http://dx.doi.org/10.1139/z91-135.

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Life histories and distribution of mayflies (Insecta: Ephemeroptera) were investigated in 11 streams in south central Ontario that ranged from highly acidic to circumneutral. At least 29 mayfly species were recorded from the streams, with 16 common enough for life history analysis. Mayfly distribution and diversity were correlated with pH regime and stream size. No mayflies were found in the smallest, most acid stream, and numbers of mayfly species and their relative abundances generally increased with both increasing stream size and stream pH. Incorporation of life cycle information with distributional data enabled us to determine the precise stream-water pH range encountered by different mayfly life stages in the study streams. Generally, during the period of greatest acid stress in the streams (pH depressions associated with spring snowmelt) the mayflies were present in large or dormant stages, which are believed to be more tolerant of lowered pH.

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Molot, Lewis A., P. J. Dillon, and B. D. LaZerte. "Factors Affecting Alkalinity Concentrations of Streamwater during Snowmelt in Central Ontario." Canadian Journal of Fisheries and Aquatic Sciences 46, no. 10 (October 1, 1989): 1658–66. http://dx.doi.org/10.1139/f89-211.

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Relative contributions of changes in base cations and acid anions to alkalinity decreases during spring snowmelt in 1984–86 were analyzed for 15 headwater streams and lake outflows in three central Ontario catchments. During episodes, concentration changes in ions which contributed to alkalinity decreases were partially offset by smaller changes in other ions which contributed to alkalinity increases. The major contributor to alkalinity depressions was base cation dilution by snowmelt water. Akalinity depressions were more likely to be dominated by SO42− increases in streams that were more acidic. Neither nitrate nor organic acid anions were significant contributors to alkalinity depressions. Discharge was highly correlated with alkalinity in a circumneutral stream but not in an acidic stream and is consistent with dilution being less important as a cause of alkalinity depressions as streams become more acidic.

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Hudson, J. J., J. C. Roff, and B. K. Burnison. "Bacterial Productivity in Forested and Open Streams in Southern Ontario." Canadian Journal of Fisheries and Aquatic Sciences 49, no. 11 (November 1, 1992): 2412–22. http://dx.doi.org/10.1139/f92-267.

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Bacterial abundance, biomass, and heterotrophic production were measured in the water, sediment, and epilithon of forested and open streams in southern Ontario in summer 1988. Relationships of environmental variables to production were examined. The time course of nucleoside incorporation, recovery efficiency of bacterial DNA, isotope dilution, and disturbance artifacts were examined to compare bacterial production rates and to determine the appropriateness of the rate of [3H]thymidine incorporation into bacterial DNA as an estimate of bacterial production in these habitats. Water column bacterial biomass (12–97 μg C∙L−1) and heterotrophic production (0.21–67 μg C∙L−1∙h−1) were greater in open streams than in forested streams. Differences between open and forested stream sediment bacterial biomass (0.30–1.1 g C∙m−2) and heterotrophic production (18–140 mg C∙m−2∙h−1) were not as pronounced as they were in the water column. A methodological disturbance artifact may have introduced a minor bias in sediment production measurements. Epilithic bacterial biomass was 35–150 mg C∙m−2, and heterotroph production was 1.3–51 mg C∙m−2∙h−1, significantly greater (P < 0.05) in open streams than in forested streams. Epilithic production and stream water temperature were positively correlated (P < 0.05). Heterotrophic bacterial production exceeded net primary production in forested streams, but not in open streams.

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8

Reid, Scott, and Anita LeBaron. "Autumn electrofishing reduces harm to Ontario (Canada) stream fishes collected during watershed health monitoring." Conservation Evidence Journal 18 (January 1, 2021): 31–36. http://dx.doi.org/10.52201/cej18hjvu9134.

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Electrofishing surveys provide important information on watershed health, and the status of imperiled and recreationally important stream fishes. Concerns about the harmful effects of electrofishing on the endangered redside dace Clinostomus elongatus have resulted in restrictions on its use in sampling activities in the province of Ontario, Canada. However, the effectiveness of these restrictions is unproven. We undertook a paired sampling gear study in 2018-2019 to test whether an alternate gear (seine nets) or a change in electrofishing timing (autumn rather than summer) reduced harm to stream fishes. The study took place in streams located in the Greater Toronto Area. We found large differences in the frequency and magnitude of sampling-related mortalities between sampling gear and seasons. During individual surveys, electrofishing mortality never exceeded 9% in the summer or 4% in the autumn, while seining-related mortality reached 60% at two stream sites. Overall, autumn electrofishing resulted in mortality rates that were 5.6 and 15 times lower than summer electrofishing and summer seining. These results indicate that survival of Ontario stream fishes can be improved by delaying electrofishing until early autumn.

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9

Hill, Alan R., and Donna J. Lymburner. "Hyporheic zone chemistry and stream-subsurface exchange in two groundwater-fed streams." Canadian Journal of Fisheries and Aquatic Sciences 55, no. 2 (February 1, 1998): 495–506. http://dx.doi.org/10.1139/f97-250.

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Data from two headwater streams in southern Ontario provide support for conceptual models that suggest that hyporheic zone influence on stream nutrient retention is determined by the extent of surface-groundwater exchange and subsurface chemical transformation rates. The hyporheic zone (>10% stream water) was delineated by a chemical mixing equation using differences in background stream and groundwater chloride concentrations and by injections of chloride to stream flow. Good agreement between the two methods confirmed that the extent of stream-groundwater exchanges can be successfully estimated using background conservative ions as a tracer technique. During low stream flows in May-October the depth of the hyporheic zone was 2-15 cm in a 12-m sand-bottom pool, debris dam, pool reach of Glen Major stream and 15-20 cm in a 16-m gravel riffle reach of Duffin Creek. Differences between observed NO3 concentrations and concentrations predicted from background chloride indicated depletion of NO3 in the hyporheic zone at a few locations in Glen Major and at 5-10 cm depth throughout the Duffin Creek reach. NO3 and NH4 injected into stream water were reactive at only a few hyporheic sites in the streams. Upstream-downstream comparisons during injections indicated that stream retention was minor.

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10

Chu, Cindy, Nicholas E. Jones, Nicholas E. Mandrak, Andrew R. Piggott, and Charles K. Minns. "The influence of air temperature, groundwater discharge, and climate change on the thermal diversity of stream fishes in southern Ontario watersheds." Canadian Journal of Fisheries and Aquatic Sciences 65, no. 2 (February 1, 2008): 297–308. http://dx.doi.org/10.1139/f08-007.

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The availability of suitable thermal habitat for fishes in streams is influenced by several factors, including flow, channel morphology, riparian vegetation, and land use. This study examined the influence of air temperature and groundwater discharge, predictors of stream temperature, on the thermal diversity (cold-, cool-, and warm-water preferences) of stream fish communities in southern Ontario watersheds. Site-level fish sampling data were used to assess the thermal diversity of 43 quaternary watersheds using three metrics, the proportion of sites within a watershed having (i) cold-, (ii) cool-, and (iii) warm-water fishes. Our results indicated that 53.9% of the variances in cold-water and 54.1% of the variances in warm-water fish distributions within the watersheds could be attributed to groundwater discharge and air temperature variables. Climate change scenarios suggested that watersheds with high groundwater discharge and the associated thermal diversity of fishes within those watersheds are less sensitive to climate change than watersheds with low groundwater discharge. Conservation of groundwater resources will be required to lessen climate change impacts on the thermal habitat and thermal diversity of stream fishes in southern Ontario watersheds.

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11

Rempel, R. S., and A. D. Harrison. "Structural and functional composition of the community of Chironomidae (Diptera) in a Canadian Shield stream." Canadian Journal of Zoology 65, no. 10 (October 1, 1987): 2545–54. http://dx.doi.org/10.1139/z87-384.

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The chironomid community of Canisbay Creek, a Shield region stream flowing in Algonquin Park, Ontario, revealed substantial differences in species structure and emergence phenology to that previously described for the community of a spring-fed wooded stream in southern Ontario. These differences are attributed to the different chemical and thermal regimes in the two streams. Weekly samples were taken from anchored floating emergence traps. Of the 72 species found, 15 are undescribed. Most were either Orthocladiinae or Tanytarsini; no Diamesinae were recorded. Both univoltine and multivoltine species occurred and some of the latter became asynchronous during spring and summer. Absolute temperatures and daily thermal divergence played important parts in emergence cueing. The Chironomidae are shown to be active components in the ecosystem throughout the year, and it is argued that the season of larval growth, along with relative body size, should be considered in the functional classification of the species in this group.

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12

Seip, Hans M., Ragnhild Seip, Peter J. Dillon, and Ed de Grosbois. "Model of Sulphate Concentration in a Small Stream in the Harp Lake Catchment, Ontario." Canadian Journal of Fisheries and Aquatic Sciences 42, no. 5 (May 1, 1985): 927–37. http://dx.doi.org/10.1139/f85-117.

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A model previously used for Norwegian catchments was modified to predict discharge and sulphur concentration in a stream draining a small catchment in Ontario. The annual input of sulphur roughly balances the output, the average sulphur flux being about 1.6 g S∙m−2∙yr−1. The average dry deposition was estimated to be about 0.4 g S∙m−2∙yr−1. For good agreement between calculated and observed sulphur concentrations, it was necessary to introduce a reduction (or adsorption) process for sulphate in deeper soil layers during summer and fall. During dry periods, however, sulphate is produced by oxidation in the upper soil layer. The sulphate concentrations in streamwater during snowmelt are remarkably constant. According to model results this could be explained by the existence of a reservoir of easily soluble sulphur in the soil considerably larger than the annual sulphur flux. The basic structure of the models applied to the Ontario stream and to two streams in Norway was the same. It seems likely, therefore, that the model may, with moderate modifications, be applicable to many catchments.

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13

Kasahara, Tamao, and Alan R. Hill. "Effects of rifflestep restoration on hyporheic zone chemistry in N-rich lowland streams." Canadian Journal of Fisheries and Aquatic Sciences 63, no. 1 (January 1, 2006): 120–33. http://dx.doi.org/10.1139/f05-199.

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Stream restoration projects that aim to rehabilitate ecosystem health have not considered surfacesubsurface linkages, although stream water and groundwater interaction has an important role in sustaining stream ecosystem functions. The present study examined the effect of constructed riffles and a step on hyporheic exchange flow and chemistry in restored reaches of several N-rich agricultural and urban streams in southern Ontario. Hydrometric data collected from a network of piezometers and conservative tracer releases indicated that the constructed riffles and steps were effective in inducing hyporheic exchange. However, despite the use of cobbles and boulders in the riffle construction, high stream dissolved oxygen (DO) concentrations were depleted rapidly with depth into the hyporheic zones. Differences between observed and predicted nitrate concentrations based on conservative ion concentration patterns indicated that these hyporheic zones were also nitrate sinks. Zones of low hydraulic conductivity and the occurrence of interstitial fines in the restored cobble-boulder layers suggest that siltation and clogging of the streambed may reduce the downwelling of oxygen- and nitrate-rich stream water. Increases in streambed DO levels and enhancement of habitat for hyporheic fauna that result from rifflestep construction projects may only be temporary in streams that receive increased sediment and nutrient inputs from urban areas and croplands.

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Taylor, Barry R., and John C. Roff. "Long-term effects of highway construction on the ecology of a Southern Ontario stream." Environmental Pollution Series A, Ecological and Biological 40, no. 4 (1986): 317–44. http://dx.doi.org/10.1016/0143-1471(86)90065-6.

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15

Eimers, M. Catherine, Shaun A. Watmough, Andrew M. Paterson, Peter J. Dillon, and Huaxia Yao. "Long-term declines in phosphorus export from forested catchments in south-central Ontario." Canadian Journal of Fisheries and Aquatic Sciences 66, no. 10 (October 2009): 1682–92. http://dx.doi.org/10.1139/f09-101.

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Total phosphorus (TP) levels in many Canadian Shield lakes in central Ontario have declined over recent decades, despite increases in human activity in most watersheds. To investigate the contribution of changes in catchment export to long-term declines in lake TP, we examined temporal and spatial patterns in TP concentrations and export (1980–1981 to 2001–2002) across 11 subcatchments that drain into three lakes in which average ice-free TP levels have declined by approximately 35%. Annual stream export of TP decreased significantly by 30%–89% in eight of the 11 subcatchments, and decreases in export were driven by declines in TP concentration, not changes in stream flow. Annual average TP concentrations varied fivefold among adjacent subcatchments, and temporal patterns in annual average TP concentrations were poorly correlated. Seasonal patterns of TP concentration were most similar among streams in the spring (March–April–May), and TP export in the spring declined significantly in 10 of the 11 subcatchments. Because spring melt is the principal hydrologic event in these seasonally snow-covered basins, decreases in TP export during the spring were primarily responsible for declines observed in annual export. The drivers of changes in TP over time are unclear at this point but are the focus of current research.

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Cunjak, Richard A. "Winter habitat of northern leopard frogs, Rana pipiens, in a southern Ontario stream." Canadian Journal of Zoology 64, no. 1 (January 1, 1986): 255–57. http://dx.doi.org/10.1139/z86-040.

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The winter habitat of northern leopard frogs (Rana pipiens) in a southern Ontario stream is described from underwater snorkeling observations. Rana pipiens were located beneath rubble (13–40 cm diameter) generally where water depths were greater than 85 cm and the mean mid-depth water velocities were 22.5 cm/s. Water temperatures during the winter ranged between 0.5 and 2.1 °C. Animals were quite torpid but still capable of swimming after being disturbed. Results from a limited marking study suggest that at least some R. pipiens remain in the same stream section throughout the winter months. Competition for similar winter shelters among various species of the stream community is suggested as a possible cause of reduced stream productivity where the availability of such habitats is limited.

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17

Lam, D. C. L., A. G. Bobba, D. S. Jeffries, and D. Craig. "Modelling Stream Chemistry for the Turkey Lakes Watershed: Comparison with 1981–84 Data." Canadian Journal of Fisheries and Aquatic Sciences 45, S1 (December 19, 1988): s72—s80. http://dx.doi.org/10.1139/f88-269.

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Simulation results obtained from interfacing a hydrological model with a hydrogeochemical model are used to explain the increase of Ca2+ + Mg2+, alkalinity, and pH in a progressively buffered stream system in the Turkey Lakes Watershed, Ontario. Results from the model, which were calibrated with observed data for 1981, were confirmed with those from 1982, 1983, and 1984. The results further supported the hypothesis that the increases of the groundwater input of Ca into the lower streams contributed to the increase of alkalinity and pH in the downstream lakes which appeared to have caused a corresponding increase in the biological primary productivity in these lakes.

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Steedman, Robert J. "Modification and Assessment of an Index of Biotic Integrity to Quantify Stream Quality in Southern Ontario." Canadian Journal of Fisheries and Aquatic Sciences 45, no. 3 (March 1, 1988): 492–501. http://dx.doi.org/10.1139/f88-059.

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A multivariate measure of stream quality, the Index of Biotic Integrity (IBI), was adapted to southern Ontario and calibrated to watershed land use on a variety of spatial scales. The fish fauna at 209 stream locations on 10 watersheds near Toronto, Ontario, was sampled with a backpack electrofisher in the summers of 1984 and 1985 to provide biological information for the IBI. Watershed urbanization, forest cover, and riparian forest were measured from 1:50,000 scale topographic maps and related to IBI estimates by linear regression. Of the biological measures tested, species richness, local indicator species (brook trout (Salvelinus fontinalis) and Rhinichthys spp.), abundance of large piscivores, fish abundance, and incidence of blackspot disease were found to contribute significantly to IBI estimates. Variation in IBI estimates at the same location ranged from 0 to 8% within the sample season and from 0 to 24% between years. Linear models based on measures of watershed urbanization and forest cover accounted for 11–78% of the variation in IBI scores, depending on the spatial scale of the analysis. Significant IBI/land use relationships were found with whole-basin IBI estimates and for IBI estimates from individual stream reaches. Land use immediately upstream of sample stations was most strongly associated with stream quality as measured by the IBI.

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Borwick, Jason, Jim Buttle, and Mark S. Ridgway. "A topographic index approach for identifying groundwater habitat of young-of-year brook trout (Salvelinus fontinalis) in the landlake ecotone." Canadian Journal of Fisheries and Aquatic Sciences 63, no. 2 (February 1, 2006): 239–53. http://dx.doi.org/10.1139/f05-212.

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We used a topographic index (TI) approach to link the presence of young-of-year (YOY) brook trout (Salvelinus fontinalis) at groundwater seepage and stream sites in the landlake ecotone with subwatershed topography surrounding a set of 21 lakes in Algonquin Provincial Park, Ontario. A lakeshore site's TI value was positively related to the temperature difference between the substrate and lake surface, indicating higher TI values were associated with greater groundwater input. YOY brook trout tended to occupy lakeshore sites with relatively large TI values. Groundwater habitat available to YOY brook trout was relatively rare, with only a few sites used consistently on an annual basis. Larger lakes had fewer groundwater habitat sites per unit length of shoreline than smaller lakes. Logistic regression analysis and model selection (via Akaike's Information Criterion) indicated the odds of finding YOY brook trout increased significantly when a site was a stream and, in the summer, when there was a large difference in temperature between lake substrate and lake surface. Most of the stream sites used by brook trout were not on the Ontario base map system but were revealed by the TI approach.

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Noltie, Douglas B., and Miles H. A. Keenleyside. "Breeding ecology, nest characteristics, and nest-site selection of stream- and lake-dwelling rock bass, Ambloplites rupestris (Rafinesque)." Canadian Journal of Zoology 65, no. 2 (February 1, 1987): 379–90. http://dx.doi.org/10.1139/z87-059.

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This study examines the breeding ecology, nests, and nest-site selection of stream-dwelling rock bass, Ambloplites rupestris (Rafinesque), populating the Middle Thames River near London, Ontario. Breeding in this stream began earlier, at lower temperatures, and continued longer than in other documented lake-breeding populations. These responses were related to flooding which repeatedly thwarted breeding attempts. Nesting and spawning continued asynchronously throughout the seasons, increasing breeding opportunities. Older, larger males spawned earliest in the season, allowing them increased renesting opportunities. The duration of each stage in nesting and brood development was documented. Nests were generally larger than those of other rock bass populations. Male size and nest size were positively related. Nests were elliptical rather than circular as in lakes, reflecting the influence of water flow. Males demonstrated nest-site selection: individual nest sites were allocated nonrandomly with respect to depth, reflecting the availability of appropriate nesting substrates, and the majority of nests were constructed downstream from obstructions to current. Many of these features of rock bass reproduction can be interpreted as being responses to the relatively variable and rigorous environment of the stream habitat as compared with lakes.

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Beam, B. D., and G. B. Wiggins. "A comparative study of the biology of five species of Neophylax (Trichoptera: Limnephilidae) in southern Ontario." Canadian Journal of Zoology 65, no. 7 (July 1, 1987): 1741–54. http://dx.doi.org/10.1139/z87-269.

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The habitat, life cycle, behaviour, and food of five species of caddisflies of the genus Neophylax (N. aniqua Ross, N. ornatus Banks, N. concinnus McLachlan, N. oligius Ross, and N. fuscus Banks) were compared, based on general surveys and biweekly to monthly samples from several stream systems in southern Ontario. Larvae of four of the species, N. aniqua, N. concinnus, N. oligius, and N. fuscus, occur sequentially from the headwaters downstream and grow from late autumn through spring, but differ slightly in temporal development; adults of these species emerge in September and October, after a summer prepupal diapause. Larvae of the fifth species, N. ornatus, grow in late summer and autumn; their habitat coincides with portions of the habitats of N. aniqua and N. concinnus in cool headwater sections of streams, but adults emerge in June following a winter diapause. These species also differ in duration of diapause, case construction, location of pupal cases, and oviposition. All species graze on algae and fine organic particles from exposed surfaces of rocks. The study demonstrates that the five species of Neophylax studied differ in larval habitat and in time of development in ways that tend to keep them separate in stream systems. Evolutionary implications are considered.

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Packalen, Maara S., Susan T. Bagley, and James W. McLaughlin. "Peatland Stream Lipid Biogeochemistry Features in an Intermediate Fen Peatland, Ontario Canada." Wetlands 31, no. 2 (February 22, 2011): 353–65. http://dx.doi.org/10.1007/s13157-010-0141-8.

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O'Brien, Heather D., M. Catherine Eimers, Shaun A. Watmough, and Nora J. Casson. "Spatial and temporal patterns in total phosphorus in south-central Ontario streams: the role of wetlands and past disturbance." Canadian Journal of Fisheries and Aquatic Sciences 70, no. 5 (May 2013): 766–74. http://dx.doi.org/10.1139/cjfas-2012-0474.

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Unraveling the cause(s) of declines in total phosphorus (TP) observed over the past three decades across many forested catchments in central Ontario remains a research priority. The objectives of this paper were firstly to test the assumption that weir water chemistry is representative of catchment changes at two adjacent headwater streams that have shown declines in TP and secondly use long-term measurements of weir water quality (1980–2008) to identify potential drivers of TP declines. Longitudinal measurements confirmed that weir water chemistry is generally representative of the entire stream channel, although channel-associated wetlands have a strong influence on TP. Additionally, processes operating in wetlands dictate seasonal patterns in TP, and differences in wetland cover explain the approximately twofold difference in average TP between the two catchments. Changes in wetland cover or processes, however, cannot explain declines in TP. Rather, declines in TP are most coherent with declines in stream potassium (K) and nitrate (NO3-N), which also occurred over the past 30 years. We suggest that coincident declines in TP, NO3-N, and K may be best explained by recovery from a disturbance event.

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Noltie, Douglas B. "Migratory dynamics and characteristics of breeding pink salmon (Oncorhynchus gorbuscha) from the Carp River, eastern Lake Superior." Canadian Journal of Zoology 68, no. 4 (April 1, 1990): 684–93. http://dx.doi.org/10.1139/z90-100.

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The pink salmon (Oncorhynchus gorbuscha) inhabiting the Great Lakes are unique to their species, the completion of their life cycles occurring entirely in fresh water. This report describes the breeding migration and characteristics of spawners from the Carp River, an eastern Lake Superior tributary 70 km north of Sault Ste. Marie, Ontario. Movement into the stream began at dusk each evening in 1983, seemingly in response to decreasing light levels. Nightly catch numbers varied through the 1983, 1984, and 1985 runs with date, river discharge, wind-generated turbulence, and water temperatures, although the influence of these factors differed with sex and season. Spawners varied in size through the runs each year but not in the same fashion. Spawner size and condition varied yearly in apparent response to prey abundance. Gonad maturation was complete on stream entry more often in males than in females, though this difference was less pronounced further upstream or after time spent in the river. Degree of secondary sexual character development, complete on stream entry in both sexes, differed in even- and odd-year spawners in relation to condition. The recovery rates of spawned-out males and females did not differ. Tagged fish wandered from the Carp River at a rate of at least 7%, many to spawn in adjacent streams. Despite between-year differences in some parameters, much of the breeding ecology of these fish remains comparable to that of anadromous pink salmon.

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Reid, J. W. "Redescription of Diacyclops nearcticus (Kiefer, 1934) and description of four similar new congeners from North America, with comments on D. crassicaudis (G. O. Sars, 1863) and D. crassicaudis var. brachycercus (Kiefer, 1927) (Crustacea: Copepoda)." Canadian Journal of Zoology 70, no. 7 (July 1, 1992): 1445–69. http://dx.doi.org/10.1139/z92-201.

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Diacyclops nearcticus is redescribed from the type specimen, collected in Massachusetts, U.S.A. Four similar new congeners, some previously mistaken for D. nearcticus, are described from the U.S.A. and Canada. Diacyclops harryi n.sp. occurred in seeps, wells, an acid bog, a pitcher plant, and stream hyporheic zones in the District of Columbia, Maryland, New York, North Carolina, Pennsylvania, and Virginia. Diacyclops chrisae n.sp. was collected from the groundwater of Wye Island, Maryland, with a probable record from the hyporheic zone of a stream in Ontario. Diacyclops sororum n.sp. occurred in drift in streams in Virginia and Texas. Diacyclops alabamensis n.sp. was collected from a well in Alabama. A previous record of D. nearcticus from Missouri could not be confirmed. Some morphological details of the probable type specimens of D. crassicaudis var. brachycercus and of a specimen of D. crassicaudis s.str. from Saskatchewan are presented. North American records of D. crassicaudis s.str. and D. crassicaudis var. brachycercus are reviewed.

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26

Rustad, Steinar, Nils Christophersen, Hans M. Seip, and Peter J. Dillon. "Model for Streamwater Chemistry of a Tributary to Harp Lake, Ontario." Canadian Journal of Fisheries and Aquatic Sciences 43, no. 3 (March 1, 1986): 625–33. http://dx.doi.org/10.1139/f86-075.

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The model is an extended version of the "Birkenes" model and consists of a hydrological submodel with a snow reservoir and two soil reservoirs, a sulphate submodel, and a submodel including H+, Ca2+ + Mg2+, Al, Na+, [Formula: see text], and organic anions. Major processes incorporated are different hydrologic flow patterns during highflow and lowflow, [Formula: see text] adsorption/desorption, ion exchange, weathering, gibbsite solubility, and equilibria with CO2 in soil and stream water. The model reproduces important daily and seasonal trends in the observed streamwater chemistry. Tentative model runs have been carried out to simulate the effects of both a doubling and a 50% reduction in the present sulphur deposition. At present the pH of the stream is generally above 5.7, with values approaching pH 5.3 during snowmelt highflow. According to the simulations, lowflow pH is not sensitive to changes in deposition. At snowmelt highflow, however, a 50% reduction in the deposition could cause a pH increase of 0.2–0.5 unit whereas a doubling could result in pH depressions of 0.5–0.9 unit.

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27

Beaty, K. G. "Sediment Transport in a Small Stream following Two Successive Forest Fires." Canadian Journal of Fisheries and Aquatic Sciences 51, no. 12 (December 1, 1994): 2723–33. http://dx.doi.org/10.1139/f94-273.

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The transport of stream bedload sediment was monitored continuously in a small stream from 1975 to 1982 following forest fires in 1974 and 1980. The stream is located in the east subcatchment (170 ha) of Lake 239 in the Experimental Lakes Area, northwestern Ontario. Precipitation, stream discharge, bedload transport, and concentration of suspended materials were measured quantitatively and organic debris was observed and collected. Bedload transport increased 20-fold following the first fire and threefold after the second. Particle sizes tended to increase during the period of study. Bedload data suggest a recovery period of 5–6 yr following the first fire and a shorter one following the second. A mass budget of material load transported in a single year following recovery indicated a dominance of dissolved load (87%), followed by suspended load (10%), and bedload (3%).

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28

Hill, A. R., and J. Warwick. "Ammonium Transformations in Springwater within the Riparian Zone of a Small Woodland Stream." Canadian Journal of Fisheries and Aquatic Sciences 44, no. 11 (November 1, 1987): 1948–56. http://dx.doi.org/10.1139/f87-239.

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Field enrichments with ammonium were conducted for periods of 4–4.5 h on two springs in the riparian zone of a small woodland stream near Toronto, Ontario. Springwater lost much of the injected ammonium as it flowed over organic and sandy riparian substrates before entering the stream. Negligible nitrate release occurred during the ammonium enrichments. Laboratory experiments revealed that riparian substrates rapidly removed ammonium from enriched springwater. Sediments covered with aerated ammonium-enriched water showed a small nitrate-N increase of 9–12 μg∙L−1 after 5 h. An absence of ammonium depletion in sterilized organic substrates and very small losses in low-temperature (1 °C) incubations suggested that microbial activity rather than adsorption was responsible for ammonium uptake. The rapid loss of ammonium from springwater overlying acetylene-treated substrates, despite the complete inhibition of nitrification, indicated that microbial immobilization was mainly responsible for ammonium depletion. We suggest that ammonium transformations in spring-fed areas of overland flow within the riparian zone may contribute significantly to the regulation of nitrogen inputs to small woodland streams.

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29

Idígoras Chaumel, Almudena L., David G. Armanini, John A. Schwindt, and Adam G. Yates. "Interannual Variation of Benthic Macroinvertebrate Communities at Long-Term Monitoring Sites Impacted by Human Activities: Implications for Bioassessment." Diversity 11, no. 9 (September 16, 2019): 167. http://dx.doi.org/10.3390/d11090167.

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Bioassessment assumes that ecological conditions remain stable in the absence of environmental changes. Evidence suggests this assumption may hold for reference streams, but knowledge gaps remain for impacted streams. Our study quantified interannual variation of benthic macroinvertebrate communities, monitored for at least 14 years in eight impacted streams in the Upper Thames River watershed in Ontario, Canada. Benthic communities exhibited moderate interannual variation in relative abundance of EPT (Ephemeroptera, Plecoptera and Trichoptera) and Chironomidae taxa. Year-to-year changes were reflected in lower community persistence than that observed in studies of reference streams. In contrast, tolerance-based metrics showed minimal interannual variation, suggesting compositional changes were because of taxonomic substitutions, in which one tolerant taxon replaced another. Analyses indicated limited directionality in temporal variation for most bioassessment metrics. An exception was taxa richness, which increased at most sites, possibly because of changes in subsampling. However, no associations between calculated bioassessment metrics and measured environmental factors (stream flow and water chemistry) or sampling procedures were observed. We conclude interannual variation in ecological conditions can be substantial and may not be associated with deterministic factors routinely measured in stream assessments. We recommend increased sampling frequency and traits-based assessment as options for limiting effects of interannual variation on assessment results.

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30

Marchant, R., and G. Hehir. "A method for quantifying hand-net samples of stream invertebrates." Marine and Freshwater Research 50, no. 2 (1999): 179. http://dx.doi.org/10.1071/mf98113.

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Quantitative sampling using a hand-net can be accomplished by taking three successive catches of invertebrates from the same point on the streambed. This is a form of removal sampling. By plotting the decline in number of individuals in each catch against the total previously caught, the total population at the sampling point can be estimated. From this, the probability of capture in a single catch (p) can be calculated. For Agapetus, other trichopteran, leptophlebiid, caenid and gripopterygid larvae from a site on a tributary of the Acheron River in southern Australia, p varied from 0.66 to 0.81. Additional data for a species of Gammarus from the Credit River in Ontario gave a p value of 0.67. In three successive catches the overall probability of capture exceeded 95% for all taxa, indicating that with this degree of effort most individuals present were caught.

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31

Pugsley, C. W., and H. B. N. Hynes. "Three-Dimensional Distribution of Winter Stonefly Nymphs, Allocapnia pygmaea, within the Substrate of a Southern Ontario River." Canadian Journal of Fisheries and Aquatic Sciences 43, no. 9 (September 1, 1986): 1812–17. http://dx.doi.org/10.1139/f86-225.

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Changes in the three-dimensional distribution patterns of stonefly nymphs, Allocapnia pygmaea, beneath the streambed in the Speed River, southern Ontario, were monitored throughout their 1-yr life cycle using 270 colonization chambers. These were filled with organism-free, sieved stream gravel and buried in vertical groups of three, at three depth intervals, in three trenches positioned across a riffle. Nymphs were present throughout the year. Seasonal changes in the distribution pattern of nymphs indicated that they were able to move beneath the streambed in both the horizontal and vertical planes. Nymphs were most abundant at depth during the summer diapause, but moved up to the surface once diapause had been broken in the autumn. There was no evidence of any bankwards migration of nymphs prior to emergence. We have therefore confirmed in detail previous suggestions that stream insects move freely into and out of the hyporheic, using it as a refuge from adverse conditions on the streambed. Stream ecologists should therefore be aware of the possibilities of movement to and from the hyporheic when working with benthic invertebrates.

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32

Cunjak, Richard A., and Geoffrey Power. "Winter biology of the blacknose dace, Rhinichthys atratulus, in a southern Ontario stream." Environmental Biology of Fishes 17, no. 1 (September 1986): 53–60. http://dx.doi.org/10.1007/bf00000401.

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33

Brunskill, G. J., and P. Wilkinson. "Annual Supply of 238U, 234U, 230Th, 226Ra, 210Pb, 210Po, and 232Th to Lake 239 (Experimental Lakes Area, Ontario) from Terrestrial and Atmospheric Sources." Canadian Journal of Fisheries and Aquatic Sciences 44, S1 (December 18, 1987): s215—s230. http://dx.doi.org/10.1139/f87-297.

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The activities of 238U, 234U, 230Th, 226Ra, 210Pb, 210Po, and 232Th were measured in seasonal samples of stream runoff water, suspended and bedload sediments, and bulk precipitation. These nuclides were also determined in stream drainage area soils and bedrock. From these measurements and hydrological data, an estimate of the annual supply of these nuclides to Lake 239 at the Experimental Lakes Area (ELA) was made. Because of low concentrations of major ions, suspended sediments, and low pH, many common stream transport mechanisms for these nuclides are not available, and we propose that dissolved organic carbon is important in this respect. The annual flux (per unit stream drainage area) of these nuclides to the lake is similar to fluxes calculated for larger rivers of the world. Uranium-234 is transported preferentially to 238U at activity ratios of 1–1.3. Radium-226 is carried in solution in proportion to Ca++. The major supply of 210Pb to the lake is from atmospheric fallout on the lake surface area. There are insufficient 222Rn or 210Pb deficits in the soil profiles to balance the measured excess 210Pb in surface soils and lake sediments. Partition coefficients for these nuclides were calculated from data on stream suspended sediments and stream water; U and Ra coefficients were ≈ 104, and Th, 210Pb, and 210Po coefficients were 104 to 105.

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34

DeBues, Max J., M. Catherine Eimers, Shaun A. Watmough, Mohamed N. Mohamed, and Jessica Mueller. "Stream nutrient and agricultural land-use trends from 1971 to 2010 in Lake Ontario tributaries." Journal of Great Lakes Research 45, no. 4 (August 2019): 752–61. http://dx.doi.org/10.1016/j.jglr.2019.05.002.

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35

Hall, Ronald J. "Responses of Benthic Communities to Episodic Acid Disturbances in a Lake Outflow Stream at the Experimental Lakes Area, Ontario." Canadian Journal of Fisheries and Aquatic Sciences 51, no. 8 (August 1, 1994): 1877–92. http://dx.doi.org/10.1139/f94-188.

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Effects of episodic experimental pH depressions on water chemistry and structure of benthic communities were investigated in northwestern Ontario, a location with low H+ deposition. Acidity levels were increased from background values of pH 6.9 to 5.0, 4.5, and 4.0 to simulate snowmelt and rainstorm events observed in south-central Ontario. Conductivity and concentrations of Ca and Mn increased significantly for all three pH disturbances. Fe and dissolved organic C remained unchanged at pH 4.5 and 4.0 but Fe increased at pH 5.0. Total and inorganic monomeric Al increased at pH 4.5 and 4.0 relative to reference areas. At pH 5.0, density decreases were observed for Baetis, Ectemnia, Simulium, and Prosimulium, at pH 4.5 for Baetis, Lepidostoma, Micropsectra, Simulium, and Prosimulium, and at pH 4.0 for Baetis, Tanytarsus, and Cricotopus. Densities of collector/filterers and clingers decreased at all pH levels, but diversity decreased in the experimental reach at pH 4.0 only. Drift density of the above genera was correlated with H+ concentration. Large reductions in macroinvertebrate densities occurred at higher pH (5.0) and during shorter exposure times compared with previous experiments in areas of higher H+ deposition in south-central Ontario and New Hampshire.

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36

Corbett, B. W., and P. M. Powles. "Spawning and Larva Drift of Sympatric Walleyes and White Suckers in an Ontario Stream." Transactions of the American Fisheries Society 115, no. 1 (January 1986): 41–46. http://dx.doi.org/10.1577/1548-8659(1986)115<41:saldos>2.0.co;2.

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37

Steedman, Robert J. "Occurrence and Environmental Correlates of Black Spot Disease in Stream Fishes near Toronto, Ontario." Transactions of the American Fisheries Society 120, no. 4 (July 1991): 494–99. http://dx.doi.org/10.1577/1548-8659(1991)120<0494:oaecob>2.3.co;2.

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38

Mosley, Erin, Stephen B. Holmes, and Erica Nol. "Songbird diversity and movement in upland and riparian habitats in the boreal mixedwood forest of northeastern Ontario." Canadian Journal of Forest Research 36, no. 5 (May 1, 2006): 1149–64. http://dx.doi.org/10.1139/x06-010.

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Little is known about the importance of riparian areas in supporting avifaunal diversity in the boreal mixedwood forest, especially outside of the breeding season. Bird populations were sampled by mist netting 18 upland and 18 riparian sites along six streams in a forested region of northeastern Ontario. Riparian sites generally had more variable vegetation than upland sites. Some riparian sites formed distinctive habitats, while others were structurally and compositionally similar to upland sites. During spring and fall migration, there was no significant difference in bird abundance or species richness between riparian and upland habitats. During the breeding period, riparian areas had greater avian species richness and abundance and more insects than upland forests, suggesting that birds were selecting these habitats because they contain more food. More birds were captured in nets placed perpendicular to the stream than parallel during the breeding and fall migration periods, suggesting that riparian areas may function as movement corridors. A greater understanding of the importance of riparian habitats to songbird communities is needed if we are to maximize the effectiveness of these regions for conserving avian biodiversity in the boreal mixedwood forest.

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39

Rutherford, Jane E. "Patterns of dispersion of aquatic insects colonizing artificial substrates in a southern Ontario stream." Canadian Journal of Zoology 73, no. 3 (March 1, 1995): 458–68. http://dx.doi.org/10.1139/z95-053.

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Modified artificial turf substrates were readily colonized by stream invertebrates, supporting 20 or more taxa after 10 or 22 days in the stream. Of the individuals present, 50–80% belonged to four taxa: Hydropsychidae, Hydroptila sp. (larvae and pupae), Rheotanytarsus sp., and Baetidae. All four taxa displayed significantly aggregated patterns of dispersion (as shown by Clark–Evans–Donnelly indices) on most of the 6 substrates. The hydropsychids and the Hydroptila sp. pupae appeared to have the highest degree of aggregation, especially at high densities; both taxa occupied about the same areas on the substrates, forming discrete bands of occupation at the upstream and downstream edges as well as along a narrow band near the middle of the substrates. Weakly positive (but generally nonsignificant) Φ2 values (intertaxon association indices based on presence–absence data) coupled with negative Iai values (intertaxon association indices based on joint abundances) for the Hydropsychidae – Rheotanytarsus sp. and Hydroptila sp. – Rheotanytarsus sp. pairings indicate that Rheotanytarsus sp. occupies quite different areas of the substrates than either the hydropsychids or Hydroptila sp. pupae, suggesting that competition for space may be important amongst these sessile taxa.

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40

Chu, Cindy, and Nicholas E. Jones. "Do existing ecological classifications characterize the spatial variability of stream temperatures in the Great Lakes Basin, Ontario?" Journal of Great Lakes Research 36, no. 4 (December 2010): 633–40. http://dx.doi.org/10.1016/j.jglr.2010.08.006.

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41

Hall, Ronald J., and Fredric P. Ide. "Evidence of Acidification Effects on Stream Insect Communities in Central Ontario Between 1937 and 1985." Canadian Journal of Fisheries and Aquatic Sciences 44, no. 9 (September 1, 1987): 1652–57. http://dx.doi.org/10.1139/f87-201.

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Aquatic insect surveys were conducted in two low-alkalinity streams in Algonquin Provincial Park, Ontario, Canada, that were first studied 48 yrs ago (1937–42). At a site where current spring pH fluctuations are small (pH 6.4–6.1), most of the same taxa that were present in 1984–85 were observed during the original surveys. However, at sites where large spring pH depressions are currently observed (pH 6.4–4.9), many mayfly and stonefly taxa that were present 48 yr ago and that are known to be intolerant of low pH (pH <5) were not recorded in 1984–85. An invasion of acid-tolerant mayfly and stonefly taxa occurred at sites with large pH depressions. Species replacements from acid-sensitive to acid-tolerant insects suggest that poorly buffered surface waters in this region have acidified sometime within the last five decades.

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42

Servos, Mark R., and Gerry L. Mackie. "The effect of short-term acidification during spring snovvmelt on selected Mollusca in south-central Ontario." Canadian Journal of Zoology 64, no. 8 (August 1, 1986): 1690–95. http://dx.doi.org/10.1139/z86-254.

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Limestone and sulfuric acid were used to manipulate the pH of water in three artificial channels in the outflow of Plastic Lake, south-central Ontario, during the spring of 1982. Using artificial channels allowed the manipulation of pH during a natural pH depression (i.e., spring snowmelt) while minimizing confounding factors such as mobilization of metals from aquatic sediments. Addition of sulfuric acid extended and exaggerated the natural pH depression (from pH 5.8 to 4.8) to as low as pH 3.5 over 5 days, while addition of limestone prevented depression of pH below 6.4. Survival and reproduction of the pisidiid clams Pisidium equilaterale Prime and Pisidium casertanum (Poli) and the hydrobiid snail Amnicola limosa Say held in artificial channels were not significantly different (p > 0.05) among treatments. The survival and reproduction of A. limosa was also not affected by exposure to short-term pH depressions (e.g., 5.8 to 4.8; 4.8 to 4.3) in three south-central Ontario streams during spring snowmelt. For various life stages of both P. equilaterale and A. limosa, 96-h LC50 values were below pH 4.0, which was well below the pH observed in any stream in this study. These results suggest that recruitment failure and elimination of A. limosa from acidifying lakes noted in other studies was not a direct result of short-term pH depression during snowmelt.

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43

Lyautey, Emilie, Zexun Lu, David R. Lapen, Graham Wilkes, Andrew Scott, Tanya Berkers, Thomas A. Edge, and Edward Topp. "Distribution and Diversity of Escherichia coli Populations in the South Nation River Drainage Basin, Eastern Ontario, Canada." Applied and Environmental Microbiology 76, no. 5 (December 28, 2009): 1486–96. http://dx.doi.org/10.1128/aem.02288-09.

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ABSTRACT We investigated the prevalence and diversity of Escherichia coli strains isolated from surface waters from multiple watersheds within the South Nation River basin in eastern Ontario, Canada. The basin is composed of mixed but primarily agricultural land uses. From March 2004 to November 2007, a total of 2,004 surface water samples were collected from 24 sampling sites. E. coli densities ranged from undetectable to 1.64 Ã¯Â¿Â½ 105 CFU 100 ml−1 and were correlated with stream order and proximity to livestock production systems. The diversity of 21,307 E. coli isolates was characterized using repetitive extragenic palindromic PCR (rep-PCR), allowing for the identification of as many as 7,325 distinct genotypes, without capturing all of the diversity. The community was temporally and spatially dominated by a few dominant genotypes (clusters of more than 500 isolates) and several genotypes of intermediary abundance (clustering between 10 and 499 isolates). Simpson diversity indices, assessed on a normalized number of isolates per sample, ranged from 0.050 to 0.668. Simpson indices could be statistically discriminated on the basis of year and stream order, but land use, discharge, weather, and water physical-chemical properties were not statistically important discriminators. The detection of Campylobacter species was associated with statistically lower Simpson indices (greater diversity; P < 0.05). Waterborne E. coli isolates from genotypes of dominant and intermediary abundance were clustered with isolates obtained from fecal samples collected in the study area over the same period, and 90% of the isolates tested proved to share genotypes with fecal isolates. Overall, our data indicated that the densities and distribution of E. coli in these mixed-use watersheds were linked to stream order and livestock-based land uses. Waterborne E. coli populations that were distinct from fecal isolates were detected and, on this basis, were possibly naturalized E. coli strains.

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44

Porcal, P., P. J. Dillon, and L. A. Molot. "Seasonal changes in photochemical properties of dissolved organic matter in small boreal streams." Biogeosciences 10, no. 8 (August 16, 2013): 5533–43. http://dx.doi.org/10.5194/bg-10-5533-2013.

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Abstract. The fate of dissolved organic matter (DOM) in lakes and streams is significantly affected by photochemical transformation of DOM. A series of laboratory photochemical experiments was conducted to describe seasonal changes in photochemical properties of DOM. The stream samples used in this study originated from three different catchments in the southernmost part of the Boreal ecozone near Dorset, Ontario, Canada. A first-order kinetics equation was used to model photochemical degradation of DOM and the kinetic rate constant, K, was used as an indicator of photochemical properties of DOM. Kinetic rate constants from all three catchments showed a sinusoidal pattern during the hydrological year. K increased steadily during autumn and winter and decreased during spring and summer with a more than 3-fold range in each stream. The highest values were observed during spring melt events when DOM was flushed from terrestrial sources by high flows. The minimum rate constants were found in summer when discharge was lowest. K was strongly correlated with pH and iron. DOM molecular weight and specific absorbance at 254 nm also exhibited annual cycles corresponding to the seasonal cycles of terrestrial organic matter, but the relationships between these properties and K differed between seasons and may have been affected by previous exposure to solar radiation during transit from the catchment.

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45

Neff, Margaret R., and Donald A. Jackson. "Regional-scale patterns in community concordance: testing the roles of historical biogeography versus contemporary abiotic controls in determining stream community composition." Canadian Journal of Fisheries and Aquatic Sciences 70, no. 8 (August 2013): 1141–50. http://dx.doi.org/10.1139/cjfas-2012-0497.

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The determinants of a local-scale biological community can include both abiotic and biotic factors acting at a variety of spatial and temporal scales. Previous studies have shown that the Precambrian Shield, a broad-scale geological feature, has distinct abiotic conditions and aquatic communities in lotic systems as compared with systems off-Shield. The relative importance of historical biogeography and postglacial colonization in Ontario versus the role of contemporary abiotic conditions has been debated in determining fish community composition. In this study, we sampled fish and macroinvertebrate community data from south-central Ontario streams to examine the degree of community concordance between fishes and macroinvertebrates and to determine the main abiotic drivers for this biological distinction between Shield and off-Shield areas. This study shows that low-order lotic systems on the Shield differ both abiotically and biotically from adjacent off-Shield systems and that similar abiotic drivers are responsible for structuring both groups of taxa. However, water chemistry and land-use variables are the most important in structuring macroinvertebrate communities, whereas physical habitat plays a larger role for fish communities.

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46

Mahlum, Shad, Dan Kehler, David Cote, Yolanda F. Wiersma, and Les Stanfield. "Assessing the biological relevance of aquatic connectivity to stream fish communities." Canadian Journal of Fisheries and Aquatic Sciences 71, no. 12 (December 2014): 1852–63. http://dx.doi.org/10.1139/cjfas-2013-0646.

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Recent advances in the ability to quantify longitudinal connectivity of riverine systems is enabling a better understanding of how connectivity affects fish assemblages. However, the role of connectivity relative to other factors, such as land use, in structuring biological assemblages is just emerging. We assessed the relevance of a structural connectivity index to stream fish communities at a relatively large scale (across five watersheds of Lake Ontario) while controlling for confounding habitat variables, such as land use, elevation, and stream topology. The results were assessed to determine whether species’ sensitivities to connectivity are in accordance with expectations of life history. Our results indicated that at large scales, structural connectivity explains significant amounts of variation in community structure (1% to 5.4% as measured by Bray–Curtis similarity), but remains secondary to other habitat components. Connectivity also was significantly related to abundance in three of the seven species assessed. The lower explanatory power of our models compared with studies done at smaller scales suggests that the relevance of connectivity to fish communities is scale-dependent and diminishes relative to other environmental factors at larger spatial extents.

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47

Hall, Ronald J. "Relative Importance of Seasonal, Short-Term pH Disturbances During Discharge Variation on a Stream Ecosystem." Canadian Journal of Fisheries and Aquatic Sciences 47, no. 11 (November 1, 1990): 2261–74. http://dx.doi.org/10.1139/f90-251.

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Effects of short-term, experimental pH reduction on water chemistry and structure of benthic invertebrate communities were investigated in a south-central Ontario stream during spring and fall. With increased acidity, inorganic monomeric Al and Ca concentrations were significantly increased in stream water during spring and fall, whereas Fe, Mn, and Zn concentrations did not change. Total Al and DOC concentrations in stream water showed no constant pattern. Benthic density and generic richness during spring decreased in mineral, but not organic sediments. Total drift density did not change, but mayflies increased in the drift. In contrast, in the fall, benthic density and generic richness fluctuations were not correlated with pH disturbance, whereas drift density increased significantly during elevated acidity. Diversity and evenness of benthic invertebrates did not change above or below pH disturbance in either season. Non-metric multidimensional scaling analysis showed that discharge was the primary correlate of spring drift, whereas pH played a secondary role. In autumn, analyses demonstrated that Ca and DOC were predominant factors associated with increased drift but were related to hydrology. This study highlights the interrelationship between life history strategies of benthic invertebrates and the frequency and intensity of physical (discharge fluctuations) and chemical (pH depressions) disturbances.

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48

Jones, Nicholas E., Bastian J. Schmidt, and Stephanie J. Melles. "Characteristics and distribution of natural flow regimes in Canada: a habitat template approach." Canadian Journal of Fisheries and Aquatic Sciences 71, no. 11 (November 2014): 1616–24. http://dx.doi.org/10.1139/cjfas-2014-0040.

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Extremes of flow and patterns of flow variability limit the distribution and abundance of riverine species via a natural disturbance regime. Using a habitat template approach, we describe the distribution and characteristics of natural flow regimes in Canada based on the severity of flows, flow predictability, and flow variability. Bayesian clustering was used to group 888 gauged watersheds across Canada into 10 classes. Some flow classes were found in all provinces, whereas others showed greater regional grouping related to land physiography (e.g., Canadian Shield and ecozones). Ontario and British Columbia had the greatest diversity of flow classes. Larger river systems tended towards less harsh flow regimes and greater flow regularity than small systems. A stream–lake network pattern, particularly the presence of lakes, decreased the severity of flow. The flow metric flood-free interval was found to be a potentially misleading indicator of reduced disturbance for high-latitude streams in Canada where ice formation and persistence are important stress factors for biota. Most flow stations had an 80% or higher chance of belonging to their primary membership class. Quantifying uncertainty in class assignment can help fellow scientists and resource managers appropriately apply our findings.

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49

Bayley, S. E., D. W. Schindler, K. G. Beaty, B. R. Parker, and M. P. Stainton. "Effects of Multiple Fires on Nutrient Yields from Streams Draining Boreal Forest and Fen Watersheds: Nitrogen and Phosphorus." Canadian Journal of Fisheries and Aquatic Sciences 49, no. 3 (March 1, 1992): 584–96. http://dx.doi.org/10.1139/f92-068.

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Wildfire in the boreal forests at the Experimental Lakes Area in Ontario caused significant losses of nitrogen and phosphorus in streams. Both watershed type and fire intensity appear to determine the extent of losses. The Northeast wetland basin lost more N and P, especially TDN, TDP, TN, and TP, than did terrestrial basins, although nitrate losses were higher from terrestrial basins. Losses of nutrients after the second fire generally were not as high as after the first fire. In the East basin, which burned twice with a high fire intensity, stream concentrations of NO3−, TDN, and TN were elevated for 6 yr between the fires and remained elevated for 9 yr after the second fire In contrast, the Northwest basin burned with a lower intensity and had no significant increase in annual concentrations of P or most forms of N in the first 3 yr after the fire; only NCV concentrations increased during this period. Despite the increases in export after wildfire, net retention of TN and TP over the 18-yr period was high. In the Northeast, East, and Northwest basins, retention of TN averaged 77, 80, and 87% compared with TP retention of 51, 67, and 84%.

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50

Kreutzweiser, David P., Kevin P. Good, and Trent M. Sutton. "Large woody debris characteristics and contributions to pool formation in forest streams of the Boreal Shield." Canadian Journal of Forest Research 35, no. 5 (May 1, 2005): 1213–23. http://dx.doi.org/10.1139/x05-053.

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Abstract:

The inputs, characteristics, and function of large woody debris (LWD) were assessed in 16 mid-order (average channel widths of 37 m), moderate-gradient (approx. 1%5% channel slopes) streams in mixedwood forests of the Boreal Shield in Ontario. Three of the streams were adjacent to clearcuts, with the remainder in areas that have not been logged or recently (>70 years) burned. The average frequency (19.9 pieces·100 m1) and size (mean diameter 16.7 cm) of LWD in these streams were less than reported in most other regions and forest types. Averaged across sites, input sources were undetermined for about 50% of the LWD owing to fluvial displacement from the points of origin. Natural mortality (24%) and windthrow (15%) were primary input sources of the remaining LWD. Windthrow was highly variable and mostly associated with nearby clear-cut logging. At the three sites near clearcuts, windthrow contributed 34%62% of LWD in streams. In study reaches where active beaver colonies were observed, beaver-felled trees accounted for up to 47% of LWD inputs. The average frequency of debris dams (2.4 dams·100 m1) was less than those reported from studies in other areas and was positively correlated with an index of bottom substrate size (r = 0.72). Less than 15% of the pools in these streams were formed or influenced by LWD. Most wood pieces appeared to be ineffective as pool-forming agents because of their relatively small size and instability. In these Boreal Shield forests, it appears that most riparian trees do not live long enough or grow to sufficient size to contribute functional LWD and influence stream morphology or pool formation.

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Journal articles on the topic 'Stream ecology – Ontario'

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