Amphipod densities and indices of wetland quality across the upper-Midwest, USA

Anteau, Michael J.; Afton, Alan D.

doi:10.1672/07-53.1

Cited by 65 publications

(80 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Unfortunately, historical quantitative data for amphipod consumption are not available for regions other than NWMN, thus precluding more rigorous tests. However, the current low percentages of amphipods consumed throughout Iowa and Minnesota coupled with evidence that amphipod densities have decreased in the upper-Midwest (Anteau and Afton 2008b) strongly suggests that there has been a landscape scale decrease in the availability of amphipods, which is consistent with the SCH.…”

Section: Discussion Importance Of Amphipods In Scaup Dietsmentioning

confidence: 57%

“…Second, scaup use of wetlands is positively correlated with amphipod densities (Lindeman and Clark 1999;Strand 2005;Anteau 2006), but not correlated with chironomid densities (Strand 2005;Anteau 2006), another frequently consumed food (this study; Anteau and Afton 2006). Third, scaup continue to consume amphipods at high aggregate percentages in NDGP and COT despite apparent declines in their availability across the upper-Midwest (Anteau and Afton 2008b). Fourth, percent occurrences of amphipods in scaup diets generally were high in all regions (this study) and in South Dakota (Strand et al 2008).…”

Section: Discussion Importance Of Amphipods In Scaup Dietsmentioning

confidence: 58%

“…Samples were pooled over years and it was assumed that annual variation was less important than spatial variability Anteau and Afton 2006;Anteau and Afton 2008b).…”

Section: Statistical Analysesmentioning

confidence: 99%

“…Foraging efficiency of scaup (intraand inter-wetland) probably has decreased because amphipod densities currently are lower than that of historical levels (Anteau and Afton 2008b), and anthropogenic influences on wetlands (i.e., sedimentation and fish introductions) may be interfering with cues (e.g., turbidity of wetlands) that scaup use to identify wetlands with abundant amphipods (Anteau 2006;Anteau and Afton 2008b). Consequently, females currently might be expending more energy to procure a diet of amphipods.…”

Section: Implications Of Forage Resources On Scaup Energeticsmentioning

confidence: 99%

“…In Northwestern Minnesota, the percentage of amphipods in scaup diets was markedly (94%) lower during springs [2000][2001] than that in historical diets (springs 1986-1988), and amphipod densities in wetlands across the upper-Midwest in 2004-2005 were low, suggesting that there has been a landscape-scale decline in amphipods (Anteau and Afton 2006;Anteau and Afton 2008b;Strand et al 2008). The apparent decrease in amphipod densities in the upper-Midwest could lead to a decrease in amphipod consumption by scaup across this large landscape.…”

mentioning

confidence: 99%

See 4 more Smart Citations

Diets of Lesser Scaup during Spring Migration throughout the Upper-Midwest are Consistent with the Spring Condition Hypothesis

Anteau

Afton

2008

Waterbirds

Self Cite

View full text Add to dashboard Cite

Section: Discussion Importance Of Amphipods In Scaup Dietsmentioning

confidence: 57%

Section: Discussion Importance Of Amphipods In Scaup Dietsmentioning

confidence: 58%

“…Samples were pooled over years and it was assumed that annual variation was less important than spatial variability Anteau and Afton 2006;Anteau and Afton 2008b).…”

Section: Statistical Analysesmentioning

confidence: 99%

Section: Implications Of Forage Resources On Scaup Energeticsmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Diets of Lesser Scaup during Spring Migration throughout the Upper-Midwest are Consistent with the Spring Condition Hypothesis

Anteau

Afton

2008

Waterbirds

Self Cite

View full text Add to dashboard Cite

A Bayesian approach for temporally scaling climate for modeling ecological systems

Burg

Anteau

McCauley

et al. 2016

Ecology and Evolution

Self Cite

View full text Add to dashboard Cite

With climate change becoming more of concern, many ecologists are including climate variables in their system and statistical models. The Standardized Precipitation Evapotranspiration Index (SPEI) is a drought index that has potential advantages in modeling ecological response variables, including a flexible computation of the index over different timescales. However, little development has been made in terms of the choice of timescale for SPEI. We developed a Bayesian modeling approach for estimating the timescale for SPEI and demonstrated its use in modeling wetland hydrologic dynamics in two different eras (i.e., historical [pre‐1970] and contemporary [post‐2003]). Our goal was to determine whether differences in climate between the two eras could explain changes in the amount of water in wetlands. Our results showed that wetland water surface areas tended to be larger in wetter conditions, but also changed less in response to climate fluctuations in the contemporary era. We also found that the average timescale parameter was greater in the historical period, compared with the contemporary period. We were not able to determine whether this shift in timescale was due to a change in the timing of wet–dry periods or whether it was due to changes in the way wetlands responded to climate. Our results suggest that perhaps some interaction between climate and hydrologic response may be at work, and further analysis is needed to determine which has a stronger influence. Despite this, we suggest that our modeling approach enabled us to estimate the relevant timescale for SPEI and make inferences from those estimates. Likewise, our approach provides a mechanism for using prior information with future data to assess whether these patterns may continue over time. We suggest that ecologists consider using temporally scalable climate indices in conjunction with Bayesian analysis for assessing the role of climate in ecological systems.

show abstract

Wetland food resources for spring‐migrating ducks in the Upper Mississippi River and Great Lakes Region

et al. 2011

View full text Add to dashboard Cite

Wetlands in the Upper Mississippi River and Great Lakes Region (UMRGLR) must annually sustain populations of migrating waterfowl from the mid‐continent of North America. We used multi‐stage sampling to estimate plant and invertebrate food biomasses (kg/ha) for ducks in 3 wetland habitat types at 6 stop‐over locations in the UMRGLR during 2006 and 2007. Total biomass was greatest in palustrine emergent (PEM; ${\bar {x}}$ = 208 kg/ha, SE = 23, median = 120), followed by palustrine forested (PF; ${\bar {x}}$ = 87 kg/ha, SE = 7; median = 43), and lacustrine–riverine (LR; ${\bar {x}}$ = 52 kg/ha, SE = 7; median = 27) wetlands. Ducks that foraged in forested and LR wetlands encountered the least food abundance during spring in the UMRGLR. Our estimates of food abundance were the lowest reported among other landscape scale surveys from mid‐continent North America. About 1 in every 5 PEM wetlands and over half of our PF and LR wetlands that we sampled contained <50 kg/ha of food, suggesting many had little or no forage value to ducks during spring. Biomass of plant foods generally exceeded invertebrate biomass in all habitat types, although invertebrate biomass estimates exceeded plant biomass in 8 of 29 sites when considered by wetland type and year. Total food biomass estimates varied widely (${\bar {x}}$ = 6–425 kg/ha) between years and among habitats; thus, using global arithmetic means to estimate food abundance for conservation planning obscures fine scale temporal and spatial variation that may be necessary for management on local and sub‐regional levels. Distributions of food biomass estimates were right‐skewed, causing us to question whether arithmetic means realistically represent levels of food abundance that all ducks encounter during spring migration. Alternative measures of central tendency (e.g., median) may be more biologically realistic, particularly if spring‐migrating ducks are not distributed in an ideal‐free manner with respect to food abundance. Future research should determine how ducks distribute themselves in relation to variation in food abundance in space and time during spring migration to strengthen the biological approach to conservation planning in non‐breeding Joint Venture areas of the North American Waterfowl Management Plan. © 2011 The Wildlife Society.

show abstract

Amphipod densities and indices of wetland quality across the upper-Midwest, USA

Cited by 65 publications

References 41 publications

Diets of Lesser Scaup during Spring Migration throughout the Upper-Midwest are Consistent with the Spring Condition Hypothesis

Diets of Lesser Scaup during Spring Migration throughout the Upper-Midwest are Consistent with the Spring Condition Hypothesis

A Bayesian approach for temporally scaling climate for modeling ecological systems

Wetland food resources for spring‐migrating ducks in the Upper Mississippi River and Great Lakes Region

Contact Info

Product

Resources

About