Influence of Item Distribution Pattern and Abundance on Efficiency of Benthic Core Sampling

Behney, Adam C.; O'Shaughnessy, Ryan; Eichholz, Michael W.; Stafford, Joshua D.

doi:10.1007/s13157-014-0570-x

Cited by 13 publications

(11 citation statements)

References 34 publications

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“…Samples were collected in freshwater impoundments and unmanaged salt marsh, and we further separated salt marsh into four categories: high marsh (irregularly flooded by tides), low marsh (regularly flooded), mudflat, and subtidal habitats. Cores were collected with a polyvinyl chloride (PVC) corer measuring either 5.1 (NJ1 and NJ2) or 10.2 cm in diameter (NY and VA), pushed into the substrate to 12.7 cm in depth; Behney et al (2014) showed that the size of the core sample has only a weak effect on the precision of energy estimates. After collection, samples were fixed with 10% buffered formalin and dye and stored for later processing.…”

Section: Methodsmentioning

confidence: 99%

“…Unfortunately, we found that the most appropriate model to fit to the data varied dramatically among sites and habitats; fitting the same degree polynomial to different data sets did a poor job of consistently estimating the point of diminishing returns. Visual approximation is likely the best method for identifying the point of diminishing returns in highly variable data (Bond et al 2001). Here, we visually estimated the point of diminishing returns (rounded to the nearest five cores) for each habitat at each site.…”

Section: Methodsmentioning

confidence: 99%

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Assessing Uncertainty in Coastal Marsh Core Sampling for Waterfowl Foods

Ringelman

Williams

Coluccy

2015

Journal of Fish and Wildlife Management

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Quantifying foraging resources available to waterfowl in different habitat types is important for estimating energetic carrying capacity. To accomplish this, most studies collect soil-core samples from the marsh substrate, sieve and sort food items, and extrapolate energy values to wetland or landscape scales. This is a costly and time-intensive process; furthermore, extrapolation methods yield energy estimates with large variances relative to the mean. From both research and management perspectives, it is important to understand sources of this variation and estimate the number of soil cores needed to reduce the variance to desired levels. Using 2,341 cores collected from freshwater and salt marsh habitats at four sites along the Atlantic Coast, we examined sampling variation and biological variation among sites and habitats. When we removed extreme outliers in the data caused by large animal food items found in a small core sample, estimates of energy density decreased by an order of magnitude for most habitats. After removing outliers, we found inconsistent geographical variation among habitat types that was especially pronounced in freshwater and no evidence for within-season temporal depletion of food resources for any site or habitat. We used a Monte Carlo simulation approach to estimate the optimal number of cores (minimizing both cost and estimated variance) sampled in each habitat type. Across most contexts, a reduction in the coefficient of variation reached diminishing returns near 40 core samples. We recommend that researchers explicitly address outliers in the data and managers acknowledge the imprecision that can arise from including or excluding outliers when estimating energy density at landscape scales. Our results suggest that collecting 40–50 cores per habitat type was sufficient to reduce the variance to acceptable levels while minimizing overall sampling costs.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Assessing Uncertainty in Coastal Marsh Core Sampling for Waterfowl Foods

Ringelman

Williams

Coluccy

2015

Journal of Fish and Wildlife Management

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“…Previously, researchers have demonstrated the effects of sample gear and acquisition (Behney et al 2014;Ringelman et al 2015), preservation method (Salonen and Sarvala 1985), sorting (Hagy et al 2011), subsampling (Stafford et al 2011), and other factors (Williams et al 2014) on estimating biomass of waterfowl foods from core samples, but data were previously unavailable on the effects of processing solvents on biomass estimates. Contrary to our original hypothesis, we found a negative effect on wet biomass of exposing larvae to H 2 O 2 , but consistent with our hypothesis we found no substantial effect of H 2 O 2 on dry mass during typical periods of exposure to H 2 O 2 (,5 min).…”

Section: Discussionmentioning

confidence: 99%

Effects of Hydrogen Peroxide as a Core Sample Processing Solvent on Invertebrate Biomass

Hagy

McKnight

2016

Journal of Fish and Wildlife Management

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Scientists estimate biomass of invertebrates to evaluate wetland management practices, estimate energetic carrying capacity for wildlife, assess habitat condition and disturbance, and quantify ecosystem services. For waterfowl and other waterbirds in North America, carrying capacity in migratory and wintering regions is estimated using food density, of which invertebrates can be a significant component. However, we are not aware of previous literature that has described the effects of reagents used during core sample processing on invertebrate biomass and abundance. We tested the effects of hydrogen peroxide on aquatic invertebrates to determine whether a reagent used to disassociate soils during core sample processing biased estimates of biomass and abundance. Wet masses of chironomid larvae were less (x ¼ 23.5% loss) in samples exposed to hydrogen peroxide than those exposed only to tap water and biomass decreased approximately 2.9% with each minute of exposure time. Dry mass of larvae was less in samples exposed to hydrogen peroxide than in those exposed only to tap water (x ¼ 2.5% loss), but we did not detect an effect of exposure time on mass lost. Hydrogen peroxide did not influence the abundance of macro-or microinvertebrates in test samples. Thus, bias associated with dry mass estimates of invertebrates from core samples treated with hydrogen peroxide is likely minimal in terms of application in energetic carrying capacity models. However, use of hydrogen peroxide during core sample processing may cause significant bias if biomass estimates are based on wet mass.

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“…All core samples were 5 cm in diameter (Behney et al ) and 5 cm deep (Evans‐Peters ) and included the water column. If a random core sample location was deeper than 50 cm, I noted the conditions but did not collect a core sample because these are not conditions associated with feeding by dabbling ducks; I then selected a new random core location.…”

Section: Methodsmentioning

confidence: 99%

The Influence of Water Depth on Energy Availability for Ducks

Behney

2020

J Wildl Manag

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Habitat management and planning strategies for nonbreeding ducks are focused on providing enough energy to support a desired number of individuals. Therefore, regional estimates of energy availability for nonbreeding ducks are required to determine if sufficient habitat exists for them. I used core sampling to estimate food and energy density in 6 types of water bodies (i.e., actively and passively managed emergent wetlands, playas, small and large reservoirs, and sloughs) in northeastern Colorado, USA, during 3 sampling occasions throughout 2 nonbreeding seasons, 2015–2016 and 2016–2017. Also, I used precise depth measurements to estimate the percentage of each site that was shallow enough to facilitate feeding by dabbling ducks as a way to correct overall energy density to reflect availability to ducks. Emergent wetlands contained the greatest food and energy density, followed by playas and sloughs, and reservoirs contained little food or energy. Fall depletion of food was greatest in actively managed emergent wetlands and spring depletion was greatest in sloughs and passively managed emergent wetlands. Mean percentage of passively managed emergent wetlands, actively managed emergent wetlands, small reservoirs, large reservoirs, and sloughs shallower than 50 cm was 37%, 77%, 10%, 4%, and 83%, respectively. Incorporating these estimates into the energetic carrying capacity model developed by the Playa Lakes Joint Venture for eastern Colorado resulted in a 54% decrease in overall duck energy day estimates, which is below what is needed to support population goals. This research identifies the need for additional wetland restoration in eastern Colorado to meet energy requirements of nonbreeding ducks and provides information to conservation planners to make more informed decisions about the extent and location of wetland restoration activities. © 2020 The Authors. The Journal of Wildlife Management published by Wiley Periodicals, Inc. on behalf of The Wildlife Society.

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Influence of Item Distribution Pattern and Abundance on Efficiency of Benthic Core Sampling

Cited by 13 publications

References 34 publications

Assessing Uncertainty in Coastal Marsh Core Sampling for Waterfowl Foods

Assessing Uncertainty in Coastal Marsh Core Sampling for Waterfowl Foods

Effects of Hydrogen Peroxide as a Core Sample Processing Solvent on Invertebrate Biomass

The Influence of Water Depth on Energy Availability for Ducks

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