Comparison of Three Benthic Macroinvertebrate Passive Sampling Devices for Non-Wadeable Streams

Rivers and streams provide essential ecosystem services to the degree that the monitoring and maintenance of these systems becomes imperative. Biomonitoring provides managers and policymakers with the tools to make informed decisions, and macroinvertebrates are often the object of biomonitoring because they are ubiquitous in most systems and are known to be good indicators of water quality. However, methods for sampling macroinvertebrates in non-wadeable streams (i.e., large rivers) have not been standardized across states and regions and an established method for macroinvertebrate biomonitoring in large rivers of Georgia is not currently available. My study compared macroinvertebrates collected with three types of passive sampling devices to assess their suitability for sampling non-wadeable systems. Hester-Dendy samplers, mesh packs filled with swamp laurel oak (Quercus laurifolia) leaves (leaf samplers), and mesh packs filled with laurel oak sticks and twigs (wood samplers) were deployed at three sites on the Savannah River and three sites on the Ogeechee River for approximately 30 days during the fall of 2014. I examined mean, standard deviation, and variance components from 53 common bioassessment metrics and 2 multi-metric indices to identify differences in colonizing macroinvertebrates between the sampling devices. I estimated variance components using 2-way ANOVA to determine sources of variation (e.g., sites or devices). I further compared assemblages colonizing sampling devices using Permutational Multivariate Analysis (PERMANOVA) followed by Similarity Percentages (SIMPER) analysis. The abundance of true flies (Order: Diptera), the abundance of midges (Family: Chironomidae) and 9 of the 53 metrics (i.e., Diptera taxa, % Amphipoda, % Gastropoda, % Oligochaeta, % Dominant individuals, Dominant individuals, Collector taxa, % Predator, and % Burrower) were determined as significantly different between sampling devices based on a 2-way ANOVA. Macroinvertebrate assemblages colonizing the three sampling devices differed (PERMANOVA; F14,37=1.6078, P=0.001), and SIMPER results showed these differences were driven by the proportions of taxa collected by each device. Estimates of variance components attributed large percentage (i.e., \u3e20%) of variability to sites, rather than devices, with the exception of % Predator and Diptera taxa. My study suggests all three sampler types are suitable for collecting macroinvertebrate from non-wadeable systems and determining the precision and overall efficiency of sampling devices is an important step towards developing standard operating procedures for the bioassessment of large rivers

Bioassessments Techniques for Benthic Macroinvertebrate in the Savannah and Ogeechee River

Bioassessments are an essential surveillance tool for determining the health of streams and rivers. Benthic macroinvertebrates are commonly used for bioassessment in wadeable streams, however a standardized method for sampling in non-wadeable streams has not been developed for rivers in Georgia. This study was conducted to determine the effectiveness and potential biases of three bioassessment techniques. Mesh bags filled with leaves (leaf packs), Masonite boards (Hester-Dendy samplers), and mesh bags filled with woody debris (snag bags) were deployed during the fall of 2014 at three sites on the Savannah River (N=26) and three sites on the Ogeechee River (N=26). After 30 days, samplers were retrieved and colonizing macroinvertebrate assemblages were assessed for differences in: Richness (EPT Taxa, Diptera Taxa, Trichoptera taxa), Composition (%EPT, %Trichoptera, %Chironomidae, % Diptera), Tolerance (Hilsenhoff Biotic Index), Functional Feeding Group Structure, Habit, diversity (Shannon Wiener, Simpson) and community structure. Macroinvertebrate assemblages differed significantly in Diptera abundance (F10,34=4.6248 P=0.0004), Chironomidae abundance (F10,34=4.7010 P=0.0003) and % burrower (F10,34=2.2688 P=0.0368). Macroinvertebrate assemblages colonizing the different sampling devices also differed significantly (PERMANOVA, F12,34=1.6056 P=0.002). SIMPER analysis revealed that the samplers collected similar taxa, but the number of individuals collected from a few taxa differed between sites. There were also no significant differences when the Georgia Multi-Metric Index, a common tool used in wadeable streams, was applied to site specific data suggesting that all three samplers provide efficient means for collecting macroinvertebrates for biomonitoring purposes in larger rivers. However, Hester-Dendy samplers provide a standard sampling surface for the calculation of macroinvertebrate density and biomass and are relatively easier to process than either leaf packs or snag bags. Our study provides a comparative assessment of these three passive sampling devices for the collection of macroinvertebrates in large, non-wadeable river systems in Georgia. Therefore, our results can be used to guide future management practices for the collection of macroinvertebrates for bioassessment in large rivers of the region

Assessment of Benthic Macroinvertebrate Apsive Samplers for Southeastern Coastal Plain Non-Wadeable Streams

Macroinvertebrates are widely used for bioassessment, however a standardized method for sampling in non-wadeable streams has not been developed in Georgia. This study was conducted to determine the effectiveness and biases of three types of passive sampling devices within the Savannah and Ogeechee Rivers of the Southeastern Coastal Plain Ecoregion. We deployed three replicates of leaf packs, snag bags, and Hester-Dendy samplers at six sites for ~30d during the fall of 2014 to assess for differences in macroinvertebrate community structure between sampling devices. In addition, we used common bioassessment metrics to evaluate for differences in scores between sampling devices. Macroinvertebrate assemblages colonizing the sampling devices differed (PERMANOVA, F14,37 =1.6078 P=0.001) however, analyses revealed that these differences were driven by varying contributions of individual groups with each sampler collecting almost identical taxa at each site. Results also showed no significant differences between common metrics. Therefore, all samplers provided an efficient means for collecting site specific macroinvertebrates, however Hester-Dendy samplers provided a standard sampling surface for the calculation of biomass

Comparison of Benthic Macroinvertebrates Colonizing Three Types of Passive Samplers for Non-Wadeable Streams

This talk was given during the South Carolina Water Resources Conference

Comparing Three Types of Passive Samplers for the Assessment of Macroinvertebrates in Non-Wadeable Rivers

Passive samplers provide an alternative method for assessing macroinvertebrate communities in large streams where traditional sampling techniques may not be feasible or effective. This study was conducted to determine the effectiveness and potential biases of three passive samplers using the GA multi-metric index (MMI) as a standardized tool to compare assemblages colonizing the different devices. Nine replicates each of mesh bags filled with leaves (leaf packs), and masonite boards (Hester-Dendy samplers), and eight replicates of mesh bags filled with woody debris (snag bags), were deployed during the fall of 2014 at three sites on the Savannah River (N=26) and three sites on the Ogeechee River (N=26). After 30 days, samplers were retrieved and macroinvertebrate assemblages were assessed for differences in: Richness (EPT Taxa, Diptera Taxa), Composition (%EPT, %Trichoptera), Tolerance (Hilsenhoff Biotic Index), Functional Feeding Group Structure (Predator Taxa), and Habit (Clinger Taxa). Differences in macroinvertebrate assemblages collected were minimal between the samplers, with each substrate-type scoring similarly in most metrics. However, there were slight differences in scores for one of the Richness metrics (Diptera taxa). Furthermore, the GA MMI had similarly high scores for all samplers at both river basins. Our study suggests that all three devices provide efficient means for sampling macroinvertebrates in large Coastal Plain rivers

Impacts of detritivore diversity loss on instream decomposition are greatest in the tropics

It is unclear whether stream detritivore diversity enhances decomposition across climates. Here the authors manipulate litter diversity and examine detritivore assemblages in a globally distributed stream litterbag experiment, finding a positive diversity-decomposition relationship stronger in tropical streams, where detritivore diversity is lower

Impacts of detritivore diversity loss on instream decomposition are greatest in the tropics

The relationship between detritivore diversity and decomposition can provide information on how biogeochemical cycles are affected by ongoing rates of extinction, but such evidence has come mostly from local studies and microcosm experiments. We conducted a globally distributed experiment (38 streams across 23 countries in 6 continents) using standardised methods to test the hypothesis that detritivore diversity enhances litter decomposition in streams, to establish the role of other characteristics of detritivore assemblages (abundance, biomass and body size), and to determine how patterns vary across realms, biomes and climates. We observed a positive relationship between diversity and decomposition, strongest in tropical areas, and a key role of abundance and biomass at higher latitudes. Our results suggest that litter decomposition might be altered by detritivore extinctions, particularly in tropical areas, where detritivore diversity is already relatively low and some environmental stressors particularly prevalent