Cade-Menun B.J.,Agriculture and Agri Food Canada |
Bell G.,Agriculture and Agri Food Canada |
Baker-Ismail S.,Agriculture and Agri Food Canada |
Baker-Ismail S.,University of Regina |
And 5 more authors.
Canadian Journal of Soil Science | Year: 2013
To develop appropriate beneficial management practices (BMPs) for a watershed, it is essential to quantify the nutrients lost from agricultural fields and to identify the mechanisms of nutrient transport. To determine appropriate BMPs for a watershed in southeastern Saskatchewan, nutrient concentrations were measured in spring 2010 in snowmelt runoff from fertilized annual cropland (zero till) and perennial tame pastures. The majority of nutrient loss was in dissolved form, rather than as particulates. Significantly more nitrogen (N) was lost from pastures as dissolved ammonium than from cropland, while significantly more dissolved organic N was lost from croplands. Although there were no significant differences in total phosphorus (P) loss, there were significantly higher concentrations of dissolved reactive P in runoff from cropland, and significantly higher particulate P in runoff from pastures. Total carbon (C) in runoff was higher from cropland, due mainly to significantly higher dissolved organic C concentrations. Runoff from cropland contained significantly higher concentrations of dissolved potassium and sulfur, reflecting the fertilization of cropland fields with these nutrients. These preliminary results demonstrate that nutrients may be transported from agricultural lands by different mechanisms (e.g., in dissolved versus particulate forms) as a function of cropping system, requiring the development of specific types of BMPs to best control nutrient losses.
Webb J.M.,University of Guelph |
Jacobus L.M.,Indiana University |
Funk D.H.,Stroud Water Research Center |
Zhou X.,BGI |
And 7 more authors.
PLoS ONE | Year: 2012
DNA barcoding of aquatic macroinvertebrates holds much promise as a tool for taxonomic research and for providing the reliable identifications needed for water quality assessment programs. A prerequisite for identification using barcodes is a reliable reference library. We gathered 4165 sequences from the barcode region of the mitochondrial cytochrome c oxidase subunit I gene representing 264 nominal and 90 provisional species of mayflies (Insecta: Ephemeroptera) from Canada, Mexico, and the United States. No species shared barcode sequences and all can be identified with barcodes with the possible exception of some Caenis. Minimum interspecific distances ranged from 0.3-24.7% (mean: 12.5%), while the average intraspecific divergence was 1.97%. The latter value was inflated by the presence of very high divergences in some taxa. In fact, nearly 20% of the species included two or three haplotype clusters showing greater than 5.0% sequence divergence and some values are as high as 26.7%. Many of the species with high divergences are polyphyletic and likely represent species complexes. Indeed, many of these polyphyletic species have numerous synonyms and individuals in some barcode clusters show morphological attributes characteristic of the synonymized species. In light of our findings, it is imperative that type or topotype specimens be sequenced to correctly associate barcode clusters with morphological species concepts and to determine the status of currently synonymized species. © 2012 Webb et al.
Roche E.A.,University of Tulsa |
Gratto-Trevor C.L.,Environment Canada |
Goossen J.P.,Environment Canada |
White C.L.,Saskatchewan Watershed Authority
Auk | Year: 2012
Flooding can cause widespread nest failure and chick mortality in sandbar- and beach-nesting waterbirds, particularly when human activity has either altered natural hydrology or limited available nesting habitat. Such widespread reproductive failure could increase breeding-season dispersal, leading to the abandonment of established nesting sites. We examined how annual movement (ψ) varied by sex, reproductive success, and flooding in three Piping Plover (Charadrius melodus) breeding areas in Saskatchewan during 2002-2009, using a multistate capture-mark-recapture model in Program MARK (n = 782). On average, female Piping Plovers were twice as likely as males to disperse and both sexes were more likely to disperse following years of poor versus moderate reproductive success (minimum to maximum values: ψno-fledglings, 0.0054-0.0998 vs. ψtwo-fledglings, 0.0017-0.0607). In addition, breeding Piping Plovers exhibited higher dispersal following flood years, even in years of moderate reproductive success (minimum to maximum values: ψmales-flood, 0.0025-0.0653 vs. ψmales-noflood, 0.0019-0.0399; and ψfemales-flood, 0.0092-0.1089 vs. ψfemales-no flood, 0.0070-0.0666). Consecutive floods could force Piping Plovers to nest at artificially high densities in new habitats that may be ill-suited to reproductive success. Given the benefits of site familiarity to reproductive success and survival, we recommend that conservation planning consider dispersal of breeding adults, in addition to nests and chicks, when water levels are managed at nesting locations used by Piping Plovers. © 2012 by The American Ornithologists' Union. All rights reserved.
Davies J.-M.,Saskatchewan Watershed Authority |
Bothwell M.L.,Environment Canada
Freshwater Biology | Year: 2012
1. The response of stream periphyton to the addition of limiting nutrients has been the focus of many studies. However, the influence of pulsed nutrient additions has not previously been examined. This study investigates the biomass accrual and physiological responses of phosphorus-limited lotic periphyton to hourly phosphate fluxes. 2. Two pulsing experiments were conducted: (i) a variable flux trial that compared variable hourly P-fluxes, delivered either continuously at different concentrations or at the same concentration but in pulses of differing duration per hour and (ii) a constant flux trial that compared periphyton responses at a set hourly P-flux but delivered in pulses of varying concentration and duration. 3. Growth response and alkaline phosphatase activity during the variable flux experiment showed that periphyton responds to the hourly integrated flux of phosphorus, regardless of whether the nutrient is supplied in short concentrated pulses or continuously at much lower concentrations. 4. The constant flux experiment examined the pulse period required to attain maximum biomass for a given phosphorus flux. Periphyton response to 5-min pulses of phosphate per hour approximated the maximum biomass as that attained when the same hourly flux was added continuously. Compared with the control, there was also a substantial increase in biomass with pulses of only 1min each hour. These results demonstrate that the hourly average phosphate concentration to which periphyton communities are exposed is paramount in determining P-limited growth dynamics. 5. Species composition was not significantly different among treatments in each experiment; however, the design was to evaluate monotonic response with increasing phosphorus flux and species diversity may not respond monotonically. The data are therefore preliminary but suggest the need to determine if species diversity is generally lower when there are brief pulses of phosphate. Unlike pulse experiments that mimic lentic situations, nutrient additions were not used to completion and species success and composition was more dependent on their ability to acquire limiting nutrients rapidly rather than on their ability to take up nutrients at the lowest concentration. © 2012 Blackwell Publishing Ltd and Her Majesty the Queen in Right of Canada.
Hill M.R.J.,Ducks Unlimited Canada |
Mcmaster D.G.,Saskatchewan Watershed Authority |
Harrison T.,Saskatchewan Watershed Authority |
Hershmiller A.,Assiniboine Watershed Stewardship Association |
Plews T.,Ducks Unlimited Canada
Canadian Journal of Agricultural Economics | Year: 2011
Wetland habitat continues to be lost in many watersheds across Canada and new program tools are needed to help restore drained wetlands. We used a reverse auction to restore drained wetlands in the Assiniboine River Watershed (ARW) of east-central Saskatchewan which is an important target area for wetland restoration in the North American Waterfowl Management Plan (NAWMP). The reverse auction format was discriminative, with sealed bids and two rounds of bidding. Bidders could submit bids for 12-year term agreements and/or perpetual conservation easements, and bids were submitted by quarter section (160 acres). Bids could be either in cultivated cropland or perennial forage, and were evaluated using an environmental benefits index based on the incremental increase in predicted hatched waterfowl nests relative to bid price. Potential bidders were solicited via contacts with existing conservation project cooperators, and a public media campaign. In the first round, 20 bidders submitted 118 bids to restore 713 wetlands totaling 670 acres at a price of $837,000. All bids were for 12-year term agreements. Bid prices to restore drained wetlands within cultivated land were higher than for perennial forage. In the second round, 30 bids from seven bidders were approved to restore 211 wetlands totaling 211 acres in perennial forage at a price of $182,000. The price of successful bids varied from $20.83 to $391.22 per acre per year (average $118.52). The reverse auction provided information on cost variability and funding required for achieving NAWMP wetland restoration objectives in the ARW. © 2011 Canadian Agricultural Economics Society.