Institute for Wetland and Waterfowl Research

Stonewall, Canada

Institute for Wetland and Waterfowl Research

Stonewall, Canada
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Bloom P.M.,University of Saskatchewan | Clark R.G.,University of Saskatchewan | Clark R.G.,Environment Canada | Howerter D.W.,Institute for Wetland and Waterfowl Research | Armstrong L.M.,Institute for Wetland and Waterfowl Research
Journal of Wildlife Management | Year: 2012

Despite recent work, uncertainty remains concerning how abiotic and biotic factors affect duckling survival. Additionally, upland habitat characteristics may affect duckling survival rates but this potential relationship has largely been ignored. We evaluated several unresolved hypotheses about causes of mallard (Anas platyrhynchos) duckling survival variation, with an emphasis on assessing effects of managed and remnant natural upland habitats. During 1993-2000, 617 radio-marked females provided information about brood habitat use and duckling survival on 27 sites in prairie Canada. We contrasted a priori and exploratory models that incorporated effects of upland, wetland, weather, female, and brood-related variables on duckling survival rates. Survival was highest for ducklings when a greater proportion of their surrounding landscape (i.e., within a 500-m radius buffer around the brood) was comprised of wetlands characterized by a central expanse of open water and a peripheral ring of flooded emergent vegetation. Cold and wet weather in the first week of life resulted in lower duckling survival. In a post hoc analysis, duckling survival (of older ducklings) was negatively related to increasing proportions of managed hayland. © 2011 The Wildlife Society.

Bloom P.M.,University of Saskatchewan | Bloom P.M.,Institute for Wetland and Waterfowl Research | Clark R.G.,University of Saskatchewan | Clark R.G.,Environment Canada | And 2 more authors.
Oecologia | Year: 2013

In theory, habitat preferences should be adaptive. Accordingly, fitness is often assumed to be greater in preferred habitats; however, this assumption is rarely tested and, when it is, the results are often equivocal. Habitat preferences may not directly convey fitness advantages if animals are constrained by tradeoffs with other selective pressures like predation or food availability. We address unresolved questions about the survival consequences of habitat choices made during brood-rearing in a precocial species with exclusive maternal care (mallard Anas platyrhynchos, n = 582 radio-marked females on 27 sites over 8 years). We directly linked duckling survival with habitat selection patterns at two spatial scales using logistic regression and model selection techniques. At the landscape scale (55-80 km2), females that demonstrated stronger selection of areas with more cover type 4 wetlands and greater total cover type 3 wetland area (wetlands with large expanses of open water surrounded by either a narrow or wide peripheral band of vegetation, respectively) had lower duckling survival rates than did females that demonstrated weaker selection of these habitats. At finer scales (0.32-7.16 km2), females selected brood-rearing areas with a greater proportion of wetland habitat with no consequences for duckling survival. However, females that avoided woody perennial habitats composed of trees and shrubs fledged more ducklings. The relationship between habitat selection and survival depended on both spatial scale and habitats considered. Females did not consistently select brood-rearing habitats that conferred the greatest benefits, an unexpected finding, although one that has also been reported in other recent studies of breeding birds. © 2013 Springer-Verlag Berlin Heidelberg.

Badiou P.,Institute for Wetland and Waterfowl Research | McDougal R.,Manitoba Water Stewardship | Pennock D.,University of Saskatchewan | Clark B.,Environment Canada
Wetlands Ecology and Management | Year: 2011

North American prairie pothole wetlands are known to be important carbon stores. As a result there is interest in using wetland restoration and conservation programs to mitigate the effects of increasing greenhouse gas concentration in the atmosphere. However, the same conditions which cause these systems to accumulate organic carbon also produce the conditions under which methanogenesis can occur. As a result prairie pothole wetlands are potential hotspots for methane emissions. We examined change in soil organic carbon density as well as emissions of methane and nitrous oxide in newly restored, long-term restored, and reference wetlands across the Canadian prairies to determine the net GHG mitigation potential associated with wetland restoration. Our results indicate that methane emissions from seasonal, semi-permanent, and permanent prairie pothole wetlands are quite high while nitrous oxide emissions from these sites are fairly low. Increases in soil organic carbon between newly restored and long-term restored wetlands supports the conclusion that restored wetlands sequester organic carbon. Assuming a sequestration duration of 33 years and a return to historical SOC densities we estimate a mean annual sequestration rate for restored wetlands of 2.7 Mg C ha-1year-1 or 9.9 Mg CO2 eq. ha-1 year-1. Even after accounting for increased CH4 emissions associated with restoration our research indicates that wetland restoration would sequester approximately 3.25 Mg CO2 eq. ha-1year-1. This research indicates that widescale restoration of seasonal, semi-permanent, and permanent wetlands in the Canadian prairies could help mitigate GHG emissions in the near term until a more viable long-term solution to increasing atmospheric concentrations of GHGs can be found. © 2011 Springer Science+Business Media B.V.

Drever M.C.,University of British Columbia | Drever M.C.,Environment Canada | Clark R.G.,Environment Canada | Clark R.G.,University of Saskatchewan | And 4 more authors.
Global Change Biology | Year: 2012

Identifying and understanding why traits make species vulnerable to changing climatic conditions remain central problems in evolutionary and applied ecology. We used spring snow cover duration as a proxy for phenological timing of wetland ecosystems, and examined how snow cover duration during spring and during the entire snow season affected population dynamics of duck species breeding in the western boreal forest of North America, 1973-2007. We predicted that population level responses would differ among duck species, such that late-nesting species with reduced flexibility in their timing of breeding, i.e. scaup (Aythya spp.) and scoter (Melanitta spp.), would be more strongly affected by changing snow cover conditions relative to species better able to adjust timing of breeding to seasonal phenology, i.e. mallard (Anas platyrhynchos) and American wigeon (Anas americana). Population growth rates of scaup and scoter were positively linked to spring snow cover duration; after accounting for effects of density dependence, larger populations resulted after springs with long snow cover duration than after springs with short snow cover duration. In contrast, population growth rates of mallard and wigeon were either negatively or only weakly associated with snow cover duration. Duck population models were then incorporated with snow cover duration derived from climate model simulations under the A2 emission scenario, and these predictions suggested that late-nesting duck species will experience the most severe population declines. Results are consistent with a hypothesis that the gradual climatic warming observed in the western boreal forest of North America has contributed to and may continue to exacerbate population declines of scaup and scoter. © 2011 Blackwell Publishing Ltd.

Arnold T.W.,Institute for Wetland and Waterfowl Research | Devries J.H.,University of Minnesota | Howerter D.W.,University of Minnesota
Auk | Year: 2010

Renesting is an important strategy for coping with nest loss in many species of birds. We investigated renesting behavior of radiomarked Mallards (Anas platyrhynchos) breeding in the Canadian Prairie Parklands and found that females were persistent renesters, replacing >57% of 4,112 destroyed nests. Renesting propensity was most affected by nest initiation date, with ∼90% of unsuccessful females renesting if destroyed clutches had been initiated in April but <10% renesting for clutches initiated after 20 June. Probability of renesting declined with successive number of nesting attempts, but this was primarily an effect of initiation date. Renesting propensity increased with female age and body condition and declined for birds that had invested more time tending their previous clutch, but the latter effect was pronounced only among late-nesting females. The amount of time required to produce a replacement clutch was primarily a function of whether females were engaged in rapid follicle growth when nest failure occurred: 44% of females (383 of 870) that lost nests during early laying renested within 4 days, whereas only 2% (12 of 639) that lost nests after clutch completion renested within 4 days. Although clutch size was smaller in renests, this was entirely an artifact of later laying dates. Our results suggest that seasonal timing had the most influence on renesting behavior. Female age, body condition, and prior nesting effort had smaller, but demonstrable, influence. © 2010 The American Ornithologists' Union.

Murray J.L.,Trent University | Anderson M.G.,Institute for Wetland and Waterfowl Research | Steury T.D.,Washington University in St. Louis
Ecology | Year: 2010

Environmental perturbation can have a marked influence on abundance and trend in many animal populations, but information is scant on how numerical change relates to variability in density-dependent and density-independent processes acting on populations. Using breeding population estimates for 10 duck species from a survey area of ∼2.2 million km2 in central North America (1955-2005), we compared population growth models and related parameters among species and across time. All duck species showed evidence of density-dependent growth, and the best-fit relationship between population growth (r,) and population size (N,) was linear or convex for all species. Density dependence and associated population parameters were not related to an index of species life history strategy. Reanalysis of segmented (1955-1979, 1980-2005) r, time series, where the truncation date coincided with a putative decline in wetland availability on breeding grounds, showed that density-dependent forces were weakened during the latter time segment. Additionally, in later years most populations experienced increased first-order autocorrelation in annual counts, decreased intrinsic growth rate, increased nonlinearity in the relationship between rt and Nt, increased equilibrium return time, and increased inter-species synchrony in numbers. Such changes were not closely related to species life history strategy or to shifts in mean population size, average trend, and estimated carrying capacity. We speculate that shifts in breeding duck habitat quality altered historical predator-prey dynamics in the system and thereby underlie observed dynamical changes. The paradoxical finding that population abundance and trend do not reveal shifts in population processes highlights the need to go beyond simple numerical assessment when evaluating population responses to environmental perturbation. © 2010 by the tcologicai society ol America.

Humburg D.D.,Ducks Unlimited Inc. | Anderson M.G.,Institute for Wetland and Waterfowl Research
Wildfowl | Year: 2014

The North American Waterfowl Management Plan (NAWMP) is a continental ecosystems model for wildlife conservation planning with worldwide implications. Since established in 1986, NAWMP has undergone continual evolution as challenges to waterfowl conservation have emerged and information available to support conservation decisions has become available. In the 2012 revision, the waterfowl management community revisited the fundamental basis for the Plan and placed greater emphasis on sustaining the Plan's conservation work and on integration across disciplines of harvest and habitat management. Most notably, traditional and nontraditional users (i.e. hunters and wildlife viewers) of the resource and other conservation supporters are integrated into waterfowl conservation planning. Challenges ahead for the waterfowl management enterprise include addressing tradeoffs that emerge when habitat for waterfowl populations versus habitat for humans are explicitly considered, how these objectives and decision problems can be linked at various spatial and temporal scales, and most fundamentally how to sustain NAWMP conservation work in the face of multi-faceted ecological and social change. © Wildfowl & Wetlands Trust.

Badiou P.H.J.,Institute for Wetland and Waterfowl Research | Goldsborough L.G.,University of Manitoba
Hydrobiologia | Year: 2015

We examined the interactions of the common carp (Cyprinus carpio L.) and nutrient additions on water quality, sedimentation rates, and submerged macrophyte biomass in mesocosms in Delta Marsh, Manitoba, Canada. We wanted to determine if carp and nutrients interacted synergistically to increase phytoplankton biomass. A two-by-three duplicated, factorial design had the following treatments: (1) control mesocosms with no carp or nutrient additions; (2) low carp density and no nutrient additions; (3) high carp density and no nutrient additions; (4) no carp and nutrient additions; (5) low carp density and nutrient additions; and (6) high carp density and nutrient additions. The presence of carp increased ammonia concentrations, turbidity, and phytoplankton biomass as expected but did not increase total reactive phosphorus concentrations. The presence of carp did not appear to interact synergistically with nutrient additions to increase phytoplankton as has been suggested by others. In mesocosms with high carp density and receiving nutrient enrichment, phytoplankton appeared to be suppressed relative to mesocosms receiving nutrient enrichment only, and nutrient enrichment and low carp density. Overall, the presence of carp appears to mimic the effects of eutrophication. Our results demonstrate that carp can cause a shift from a clear, macrophyte-dominated state to a turbid phytoplankton-dominated state at a biomass of less than 600 kg ha−1. © 2015, Springer International Publishing Switzerland.

Badiou P.H.J.,Institute for Wetland and Waterfowl Research | Goldsborough L.G.,University of Manitoba
Wetlands | Year: 2010

The Common Carp (Cyprinus carpio) is an exotic benthivorous fish that can have negative impacts in aquatic ecosystems. This study examines the direct and indirect ecological impacts of Common Carp on water column nutrient concentrations, suspended solids, sedimentation, and submersed macrophytes in large (5-7 ha) experimental wetlands in Delta Marsh, Manitoba, Canada. In general, the effects of Common Carp on water quality were similar to those encountered in systems undergoing cultural eutrophication. With increasing densities of Common Carp, water column nutrient concentrations, suspended solids, and chlorophyll a increased while dissolved oxygen concentrations, submersed macrophyte density, and photic depth decreased. The wetlands did not become noticeably more turbid, contrary to our expectation, probably due to the mitigating effects of dense submersed macrophyte beds, and to high water color that likely prevented phytoplankton from flourishing. © 2010 Society of Wetland Scientists.

Devries J.H.,Institute for Wetland and Waterfowl Research | Armstrong L.M.,Institute for Wetland and Waterfowl Research
Journal of Wildlife Management | Year: 2011

Periodic treatment of established stands of dense nesting cover (DNC) is a recommended practice to maintain cover quality, but little information exists on the magnitude and duration of treatment effects on nesting waterfowl. During 1998-2001, we examined the effect of management treatments on vegetative characteristics and waterfowl nest success and density in fields of DNC seeded to introduced and native grass and forb mixes in the parklands of Saskatchewan and Manitoba. We measured vegetation height-density and litter depth within fields and located and monitored 1,927 duck nests within 33-42 fields/yr ranging in size from 6 ha to 62 ha. We considered a series of models examining the influence of grass type and management treatment (GTMT) and years post-management (YPM) on vegetative characteristics, nest success, and nest density while including covariates potentially affecting these response variables. Visual obstruction and litter depth were lowest in native-burned fields and greatest in introduced-hayed fields. Visual obstruction was low the year following management, peaked 2-3 YPM, and remained at intermediate levels through ≥6 YPM. Litter depth remained low for the first 3 YPM and increased thereafter. Nest success and nest density varied little among GTMT. Nest success was high (14.3%) the year following a management treatment, low (6.5%) at 2 YPM, and moderate thereafter. Nest success decreased with percent cropland in the surrounding landscape. Nest density was 0.7 nests/ha the first year following management, increased to approximately 1.3 nests/ha in years 2-3, and declined back to approximately 0.7 nests/ha for ≥6 YPM. Nest density decreased with field size and increased with the area of small wetlands, percent cropland, and percent wetland within surrounding landscapes. Nest density tracked vegetation density as expected and our results indicate a possible trade-off between nest density and nest success. Given ancillary data on small mammal and insect prey in our study fields, and evidence from other studies, we speculate that DNC fields may act as prey reservoirs during years of peak vegetative density with a consequent reduction in nest survival. Therefore, management to increase waterfowl production based on our results needs to consider the interaction of treatment effects, competing habitats, and surrounding landscape composition. Copyright © 2011 The Wildlife Society.

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