Waterfowl Conservation & Management II

Contributed Oral Presentations

SESSION NUMBER: 90

Contributed paper sessions will be available on-demand for the duration of the conference, then again at the conclusion of the conference.

 

Evaluating Dynamics of Food Availability for Lesser Scaup at Pools 13 and 19 of the Mississippi River
Lauren D. Larson; Michael J. Anteau; Heath M. Hagy; Joseph D. Lancaster; Aaron P. Yetter; Christopher N. Jacques
The Lesser scaup (Aythya affinis; hereafter, scaup) is an omnivorous diving duck that is a species of conservation concern in the Midwest. Since the 1970s, the continental scaup population has declined, with numbers well below the 6.3 million goal set by the North American Waterfowl Management Plan. Several factors have been implicated in the scaup decline, including decreased food availability at migratory stopover sites in the upper Midwest. Navigational Pools 13 and 19 of the Upper Mississippi River System (UMRS) are crucial refueling sites for migratory waterfowl, especially diving ducks, prior to reaching higher latitudes where food shortages have been documented. Unlike other navigational pools of the UMRS, few aquatic invertebrate and vegetation evaluations have been conducted on Pool 19. Our ongoing research seeks to create a spatiotemporal habitat assessment of Pools 13 and 19 during 2019-2020. We evaluated potential foraging biomass and habitat conditions at 50 stratified random sites on each Pool in summer 2019, with Pool 19 sites being sampled again in fall. Mean scaup food biomass from summer samples varied considerably between sites (Pool 19 = 282.4 kg/ha ± 90.8 [SE]; Pool 13 x = 1,132.1 kg/ha ± 287.2 [SE] ) and was largely dependent on the presence of gastropods and bivalves. Fingernail clams, a key diet item, were present at 68% and 92% of sites in Pool 13 and Pool 19 respectively. However, total biomass from Pool 13 fingernail clams was three times greater than that collected on Pool 19. We will be combining biomass estimates with scaup-specific true metabolizable energy values to determine the energetic carrying capacity of our study areas in response to current and future environmental change. Findings may also contribute to the geographical prioritization of conservation efforts and the development of habitat enhancement strategies.
Survival, Recovery, and Translocation of Kansas-Banded Canada Geese
J. Boomer Malanchuk; David A. Haukos; Beth E. Ross; Thomas F. Bidrowski
Resident, or temperate-breeding, Canada geese (Branta canadensis) were once extirpated in Kansas. Today, Kansas’ goose population is a valuable resource providing abundant viewing and hunting opportunities to thousands annually. Kansas Department of Wildlife, Parks, and Tourism (KDWPT) began reintroducing geese in 1980 with hopes of re-establishing the breeding population. By 1989, 10,000 geese (6,000 gosling and 4,000 adults) had been released at wildlife management areas and state reservoirs. These successful reintroductions led to translocating flocks to new parts of the state with no historic record of nesting geese. By 2001, KDWPT had stopped translocating geese to increase population abundance. Currently, KDWPT translocates nuisance flocks from urban areas to rural reservoirs with the goal of reducing overabundant urban flocks. The same method that was used to recover Canada geese from extinction is now used to manage overabundance. We used Brownie dead-recovery models to compare survival and recovery probabilities between translocated and non-translocated (normal wild) Kansas-banded Canada geese for 2012-2017. Model-estimated annual survival differed between status (normal wild S = 0.761, 95% CI 0.734-0.785; translocated S = 0.598, 95% CI 0.528-0.665). Recovery probability differed between normal and translocated adults (normal wild f = 0.074, 95% CI = 0.069-0.078; translocated f = 0.138, 95% CI = 0.120-0.158) and juveniles (normal wild f = 0.067, 95% CI = 0.059-0.075; translocated f = 0.250, 95% CI = 0.199-0.310). Recovery probability did not differ between status in the sub-adult age class (normal wild f = 0.126, 95% CI = 0.115-0.137; translocated f = 0.090, 95% CI = 0.055-0.144). Translocation successfully reduces survival and increases recovery probability of nuisance urban geese. KDWPT strives to manage resident Canada geese to maximize benefits for hunters and the public while minimizing nuisance concerns related to over-abundant geese.
Completing the Monitoring Cycle by Using Data to Improve Survey Design and Participation: An Example Using Integrated Waterbird Management and Monitoring
Mindy B. Rice; Alex Kumar; Heath Hagy
The Integrated Waterbird Management and Monitoring (IWMM) program is a monitoring protocol established in 2008 to tie bird abundance to on the ground unit conditions and management actions. About 35 refuges currently collect IWMM data, but many more refuges created specifically for waterbirds could benefit by adopting it across the National Wildlife Refuge System. However, numerous impediments including a lack of resources (staff and money), a lack of training, or prioritizing other surveys can all limit participation in IWMM. We have begun to analyze IWMM data to look at how the data can be incorporated into refuge management. We first used 3 pilot refuges to examine how habitat covariates and management actions collected as part of IWMM protocols influence waterbird abundance on wetland units. Second, we investigated whether we could minimize effort in the field by sub-sampling the wetlands for which IWMM is collected. Overall, we found that most participants were not collecting the data according to the protocol guidelines making analysis especially difficult. We also found that the only waterbird group that had enough data to analyze was waterfowl. Further, our analyses show that the majority of variables collected under IWMM have little to no predictive value for waterfowl abundance. In addition, we found that sampling of wetlands can be reduced substantially while maintaining accurate waterbird counts across the refuge. We recommend surveying at least 2/3 of all the units or 3/4 of the total survey area, leaving the units with the lowest total abundances unsurveyed. We hope that using these analyses to adapt and revise the protocol may increase both participation and adherence to protocols by refuges using IWMM.
Changes in the Autumn Migration Phenology of Waterfowl in Eastern Canada
Christian Roy; Barbara Frei; Ana Morales; Bethany G. Thurber; J. Ryan Zimmerling
Climate change has altered the migration phenologies of migratory birds across the globe. Over the last several decades, there is evidence that many species of waterfowl are conspicuously delaying autumn migration during the autumn and winter months. This shift in phenology may have extensive implications, including: loss of socioeconomic opportunities by waterfowl hunters and associated tourism, reduced efficacy of monitoring and management efforts by land managers and policy makers, and conservation implications of habitat overuse in key staging areas. Increasing our understanding of how and why waterfowl migration is changing is critical for the effective planning and management of a species group with vast ecological and cultural significance in North America. We used GLMM and GAMM models to anlayze data from migration survey and citizen science monitoring programs collected in Ontario and Quebec to quantify the shift in autumn migration chronology and identify the main drivers of changes. Our analyses demonstrated that the peak of migration occurred 3-5 days later per decades for many species such as the mallard (Anas platyrhynchos), American black ducks (A. rubripes), Canada goose (Branta canadensis) and Snow goose (Anser caerulescens) but remained unchanged for other species such as the blue-winged teal (A. discors) and the green-winged teal (A. carolinensis). There was also substantial heterogeneity in the impact of climatic drivers on the timing of the migration peak among species. Contrary to our expectations the amount of time spent on the migratory halt have remained relatively constant during the sturdy period. A key outcome of our analysis is that the development of future waterfowl management plans will need to account for the different species response to climate change.
Relative Abundance and Timing of Waterfowl Use of Key Staging Areas in Michigan
Trey McClinton; David R. Luukkonen; Daniel B. Hayes
Michigan is located in the center of the migratory funnel that is the Great Lakes Region. As such, numerous state and federally operated refuges are located throughout, and serve as major staging areas for migrating waterfowl. Since the 1970s managers of eight areas scattered across the Lower Peninsula have conducted weekly refuge counts to document waterfowl abundance through seasonal progression. These data serve as an index of yearly migration characteristics. Though periodic reviews have helped inform hunting regulations, no comprehensive assessments have been completed. We obtained and analyzed 30 years of count data with the objectives of (1) evaluating trends in the relative abundance and timing of waterfowl migrating through key areas and (2) examining how regional and local factors influence waterfowl congregation on key areas. We ran a general linear model that explained numerical week of peak abundance by year block, unique area, and the interaction between the two. We found that the main effect of area and the interaction between year block and area were significant, while main effect of year block was not. This indicates that a coarse general trend of later migration is not apparent across all sites, but certain areas routinely observe later peak abundances and that there are unique trends in the timing of observed peaks across areas. These insights have implications for establishing zones and season frameworks, as they show that waterfowl move through the various migratory corridors differently. Additionally, we observed a precipitous decline in waterfowl abundances documented when averaged across sites. This could be an indication of changing migratory corridors. Further analyses will help us understand the characteristics of observed migration and the factors influencing the congregation of migrating birds on key staging areas.
Prey Pulse Dynamics and Their Effect on Predators in a Seasonally Pulsed Wetland
David A. Essian; Dale E. Gawlik
Predator populations are often food-limited, making it crucial for wildlife managers to understand patterns and sources of spatiotemporal variation in the availability of their prey. The objectives of this study were to 1) develop a model of wading bird prey biomass based on hydropatterns, 2) hindcast the pulsed dynamics of prey over eight seasons, and 3) examine the effect of pulse dynamics on demographic responses of great egrets (Ardea alba), snowy egrets (Egretta thula) and white ibises (Eudocimus albus). We modeled the effects of environmental variables on prey biomass (g/m2) using generalized additive models for location, scale and shape (GAMLSS) with gradient boosting. Spatially explicit predictions from GAMLSS models were used to hindcast pulse curves (availability of high-quality foraging patches as a function of time) over eight nesting seasons. Effects on wading bird nest abundance and survival were assessed using variables derived from pulse curves, including amplitude, date of peak pulse, and total effect (area under the pulse curve). During the dry season, there was a pulse of prey biomass as aquatic prey migrated away from drying edges of the marsh and concentrated into depressions. Landscape-scale hydrological variables (e.g. rate of drying), and fine-scale variables (e.g. vegetation density) were both important in predicting prey pulses. Great egret nest abundance increased with pulse magnitude and total effect. For the great egret and white ibis, nest survival rates increased with date of peak pulse. Snowy egret nesting was not influenced by pulse dynamics. Our model confirms that prey biomass concentrates over hierarchical spatiotemporal scales in response to seasonal water level fluctuations. Furthermore, water management strategies that influence pulse dynamics by altering broad scale hydropatterns will subsequently influence predator responses. However, more information is required to understand management effects on fine scale variables that influence prey pulses, such as microtopography and vegetation density.
Temporal Coherence Patterns of Hydrologic and Biotic Variables in a Complex of Prairie Pothole Wetlands
Kyle I. McLean; David M. Mushet; Jon N. Sweetman
Quantifications of temporal coherence, i.e., the synchrony of measured variables between times series, can facilitate explorations into the relative importance of intrinsic and extrinsic forces shaping ecosystems. Temporal coherence indicates extrinsic forces (e.g., landscape, climate) dominate, while asynchronous patterns reflect a dominance of intrinsic forces (e.g., biotic interactions). Little is known about temporal coherence in highly dynamic systems such as prairie-pothole wetlands. We used a combination of hydrologic, macroinvertebrate, and amphibian data from 16 prairie-pothole wetlands sampled from 1992-2015 to explore patterns of temporal coherence. We quantified temporal coherence by calculating intra-class correlation coefficients (ri) for all 16 wetlands, temporarily-ponded wetlands (T-Wetlands, n=8), and permanently-ponded wetlands (P-Wetlands, n=8). For each group, we also compared ri values for three hydroclimatic periods: 1992-2015, 1992-2000 (the filling period), and 2001-2015 (the post-filling period). The filling and post-filling periods corresponded to observed changes in hydrologic conditions in the study area. We found the relative influence of extrinsic forces (i.e., coherence) in P-wetlands was greatest during the filling period when water levels were increasing in a linear fashion. We also found that the influence of intrinsic forces in P-Wetlands increased in the post-filling period when water levels were most stable. The relative influence of intrinsic forces in the T-Wetlands, which remained dynamic during both periods, was typically greater than observed in the P-Wetlands. Our results indicate that the relative influence of intrinsic and extrinsic forces is influenced by shifting ecohydrological conditions, even at the relatively small spatial scale of our study area.
Using an Agent-Based Model to Understand the Role of Landscape Composition on Wintering Mallard Body Condition, Movements and Survivalmississippi Alluvial Valley
Florian Weller; Elisabeth Webb; William Beatty; Dylan C. Kesler; Matt L. Miller; Kevin M. Ringelman; Robert H. Blenk; Sean Fogenburg
Landscape management for waterfowl conservation depends on an understanding of the complex and emergent interactions between waterfowl and behavioral, environmental and anthropogenic factors. Agent-based models (ABMs) simulate the movement and actions of thousands of individuals simultaneously, and thus offer a spatially and temporally explicit approach to evaluating the response of waterfowl populations to conservation scenarios. We present an ABM of mallards (Anas platyrhynchos) wintering in the Mississippi Alluvial Valley, which is based on the energetics-based SWAMP framework that was developed for the Central Valley of California. The model simulates food depletion and decay, changes in inundation, and human disturbance, and is extensible to cover the full non-breeding period by integrating weather-driven relocation and migration movements. The model allows for tracking mallards’ physiological and behavioural response to dynamic habitat conditions and emergent behaviours of populations at the landscape scale. The model is intended to be a tool for the evaluation of conservation allotment approaches under a range of management and future environmental conditions. We discuss model results from scenarios of alternative flooding regimes, wetland extent and food energy availability, and refugia distribution.
Quantifying Secretive Marshbird Habitat Use Across the Full Annual Cycle in the Mississippi Flyway: A Meta-Analysis
Kristen M. Malone; Elisabeth B. Webb; Doreen Mengel
Secretive marshbirds have experienced widespread population declines due to the loss of wetland habitat on which they depend. Because of their cryptic behavior, secretive marshbirds are challenging to study and information on their habitat requirements is limited, especially across the full annual cycle. Identifying flyway-wide trends in secretive marshbird habitat across the annual cycle was recognized as a priority by the Mississippi Flyway Council. Consequently, our objective was to use a meta-analysis to quantify secretive marshbird habitat trends across life history events, species, and regions within the Mississippi Flyway. We found 81 studies that quantitatively assessed habitat associations of at least one of 7 focal species, including bitterns and rails. Most studies examined breeding season habitat, whereas only 14% and 4% studied migration or winter habitat, respectively. On average, studies measured and reported 8 habitat variables, although variables were not defined and measured consistently across all studies. Marshbirds were positively associated with cattail coverage (Typha spp.; mean effect size = 0.28, 95% CI = 0.12 – 0.42, N = 20) and interspersion of water and vegetation (mean = 0.17, 95% CI = 0.03 – 0.31, N = 7). Marshbirds were negatively associated with open water (mean = -0.27, 95% CI = -0.48 – 0.02, N = 15), but there was no common effect of woody vegetation across studies (mean = 0.02, 95% CI = -0.15 – 0.19, N = 16). For each habitat variable, there was considerable heterogeneity among effect sizes that may be explained by species, season, or regional differences. However, the similarities identified across studies can guide future management of wetlands for secretive marshbirds. Future studies identifying marshbird habitat associations during migration and winter and examining a standardized set of habitat variables will facilitate better understanding of habitat requirements for secretive marshbirds throughout the full annual cycle.

 

Virtual
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