Scott Grubbs

Environmental factors affecting the distribution of aquatic invertebrates in temporary ponds in Mammoth Cave National Park, Kentucky, USA

Despite a recent surge of interest in temporary lentic systems, a strong theory linking the biota to its environment has not emerged. Using data from 10 temporary ponds at Mammoth Cave National Park, Kentucky, USA, we investigated how invertebrate communities were structured along environmental gradients, both between and within ponds. Samples were collected with a benthic corer in winter and spring, and a sweep net in spring. Six between-pond and two within-pond datasets were created. Between-pond analyses yielded significant CCA’s with only one of the six data sets. The ranges of environmental variables (EV’s) within ponds were often similar to the ranges of EV’s when averaged and compared between ponds. Some taxa were aggregated in a single pond, and richness increased with pond area. The theory that richness increases with hydroperiod did not apply to these systems. Within-pond analyses yielded more consistent relationships, with both CCA’s being significant. Sample depth was the best predictor of invertebrate richness and abundance, with most taxa preferring shallow habitats. Richness and abundance were higher in both shallow ponds and shallow areas of deep ponds than in deep areas of deep ponds. Standardizing sample depth may be an effective way to remove this gradient as a confounding variable in future research. The presence of within-pond gradients, possibly coupled with the limited dispersal and random colonization of tolerant taxa, makes between-pond comparisons difficult.

Ohio USA stoneflies (Insecta, Plecoptera): species richness estimation, distribution of functional niche traits, drainage affiliations, and relationships to other states

Abstract Ohio is an eastern USA state that historically was >70% covered in upland and mixed coniferous forest; about 60% of it glaciated by the Wisconsinan glacial episode. Its stonefly fauna has been studied in piecemeal fashion until now. The assemblage of Ohio stoneflies was assessed from over 4,000 records accumulated from 18 institutions, new collections, and trusted literature sources. Species richness totaled 102 with estimators Chao2 and ICE Mean predicting 105.6 and 106.4, respectively. Singletons and doubletons totaled 18 species. All North American families were represented with Perlidae accounted for the highest number of species at 34. The family Peltoperlidae contributed a single species. Most species had univoltine–fast life cycles with the vast majority emerging in summer, although there was a significant component of winter stoneflies. Nine United States Geological Survey hierarchical drainage units level 6 (HUC6) were used to stratify specimen data. Species richness was significantly related to the number of unique HUC6 locations, but there was no relationship with HUC6 drainage area. A nonparametric multidimensional scaling analysis found that larger HUC6s in the western part of the state had similar assemblages with lower species richness that were found to align with more savanna and wetland habitat. Other drainages having richer assemblages were aligned with upland deciduous and mixed coniferous forests of the east and south where slopes were higher. The Ohio assemblage was most similar to the well–studied fauna of Indiana (88 spp.) and Kentucky (108 spp.), two neighboring states. Many rare species and several high quality stream reaches should be considered for greater protection.

Influence of flow permanence on headwater macroinvertebrate communities in a Cumberland Plateau watershed, USA

Forested headwater systems provide critical habitat needs for diverse macroinvertebrate faunas globally. This study compared macroinvertebrate community structure between ten temporary and perennial stream channels in a Cumberland Plateau (USA) watershed. Macroinvertebrates were sampled in winter and spring over a 2-year period. Several macroinvertebrate taxa displayed distinct abundance patterns with either increasing or decreasing stream permanence. There were no individual taxa, however, that was common or abundant in one flow regime yet absent in the other. Of the 108 taxa totally collected, only nine and eight were not obtained from the temporary and perennial channels, respectively. There were several functional differences revealed between flow regimes, namely higher densities in the perennial channels for scrapers and filtering-collectors and five of six richness variables except shredders. Overall, this study revealed taxonomic similarity of macroinvertebrate assemblages between temporary and perennial channels but also subtle downstream functional changes that are typical of forested headwater systems. This implies that the longitudinal hydrologic gradient was relatively shallow and that most taxa persist across the flow regime.

Longitudinal patterns of fish assemblages in small unregulated subbasins: evaluating reach- and watershed-scale parameters

Fish assemblage relationships with environmental parameters were studied in four small unregulated subbasins in the speciose Upper Green River Basin of central Kentucky, USA. One subbasin drains into a tributary of the Green River and produced the lowest species (28) richness. The three other subbasins drain directly into the Green River and supported 41−59 species. Parameters were partitioned into watershed- and reach-scale spatial categories. Watershed area per stream segment and stream-size related environmental parameters at the reach scale produced the highest loadings of a principle components analysis (PCA), and both PCA Axes 1 and 2 for all subbasins were reflective either of watershed area or stream-size parameters. Small loadings were produced by all watershed-scale land-use parameters and all reach-scale water chemistry parameters. Fish richness and diversity were positively correlated with watershed area for the two largest subbasins and for the three Upper Green River subbasins combined. The lack of a linear relationship, however, between the residuals of multiple linear regression models between richness and diversity versus stream width, percent bedrock, percent pool and percent fine substrates indicated that a simple species area relationship was not operating. A detrended correspondence analysis (DCA) performed for each subbasin showed that several fish species were associated mainly either with small, upland segments or conversely the largest, deeper segments, and each subbasin yielded significant correlations between the environmental PCA loadings and fish assemblage DCA site scores. These results indicated that within the regional scale, and in absence of steep disturbance gradients, stream fish assemblages can reflect natural hydrologic and geomorphic gradients.

The influence of flow impoundment and river regulation on the distribution of riverine macroinvertebrates at Mammoth Cave National Park, Kentucky, U.S.A.

The effects of impoundment by a low-head dam and hypolimnetic release from a reservoir on benthic macroinvertebrate assemblages were studied in two lowland rivers. The first river (Green River) was initially divided into three zones (impounded, transitional, erosional) according to hydrological characteristics. The entire reach of the second river (Nolin River) was a regime unit. Only the Green River erosional zone was free-flowing with a linear sequence of riffle-run-pool reaches. A detrended correspondence analysis showed that the Green River impounded and transitional zones were taxonomically indistinguishable while the Green River erosional zone and the Nolin River were each distinct. A canonical correspondence analysis revealed that higher surface velocity, higher summer water temperatures and more turbid conditions, and lower water temperatures were contributing parameters to the separation of the Green River erosional zone, Green River transitional/impounded zones, and the Nolin River, respectively, in ordination space. A series of one-way ANOVA’s testing for differences of macroinvertebrates assemblages between the three Green River zones according to five metrics showed that the Green River erosional zone demonstrated significantly higher values and the transitional and impounded zones were ecologically similar.

Notes on Perlesta (Plecoptera: Perlidae) from Eastern North America

The identity of Perlesta nitida is reviewed and demonstrated to be a valid species. The male is redescribed with an emphasis on internal genitalia, and the egg stage is described for the first time. Morphological features distinguishing P. nitida from similar species are provided. New distributional records of additional Perlesta species are reported.

Perlesta shawnee (Plecoptera: Perlidae), a new stonefly species from Eastern North America

A new species of Perlidae, Perlesta shawnee, is described from the unglaciated southern portions of Illinois and Indiana. This new species belongs to the P. frisoni group, a cluster of morphologically similar species, and is most readily distinguished from the closely related P. frisoni by slender paraprocts, position of the slender mesoapical paraproct spine, and egg sculpturing.

Algal biomass accrual in relation to nutrient availability and limitation along a longitudinal gradient of a karst riverine system

Nutrient availability influences growth, productivity, and community structure of primary producers. Nutrient limitation, however, results from a deficiency mainly in nitrogen (N) or phosphorus (P) levels relative to cellular growth needs. Limitation is a function of biotic and abiotic factors, the latter including land-use activities (e.g., agriculture, septic systems) and underlying bedrock features. The purpose of this study was twofold: (1) to assess the relationship between algal biomass and ambient nutrient levels along the longitudinal course of a river through a transition from weak to well-developed underlying karst bedrock and (2) experimentally assess if periphyton was N- or P-limited between weak and well-developed karst reaches. Sestonic and Cladophora biomass (=chlorophyll-a) levels increased sharply along the longitudinal gradient. Cladophora biomass, in particular, was strongly correlated with nitrate levels. In contrast, periphyton biomass (=chlorophyll-a) levels were sporadic and did not display a longitudinal pattern. With the exception of ammonia, individual nutrient levels generally increased longitudinally and were higher in the downstream karst reaches. Total N/total P ratios also increased longitudinally and were >25 throughout the study region, suggesting P limitation. The results of the nutrient limitation studies, however, coupled with high concentrations of both N and P throughout the study reach in excess of eutrophication thresholds, suggest that total nutrients are not limiting within the study region. Overall, Kentuckys upper Green River appears to be a nutrient-enriched, eutrophic system and particularly in the downstream, well-developed karst reaches.

GIS and Artificial Neural Network-Based Water Quality Model for a Stream Network in the Upper Green River Basin, Kentucky, USA

AbstractThe prediction of stream water quality (WQ) is essential to understand and quantitatively describe water quality parameters (which include physical characteristics, inorganic metallic, and nonmetallic concentrations) and their structure, watershed health, biodiversity, and ecology of a basin. The spatial variability and temporal randomness of stream water quality parameters makes the problem a complex modeling task by ordinary statistical regression methods. The determination of water quality parameters and their spatial and temporal description in stream networks is even more complex due to the stochastic nature of water flow, atmospheric conditions, meteorological patterns, and nonlocal effects of precipitation and temperature. In this paper, a statistical, geographic information system (GIS) and a neural network based water quality model is developed to study stream water quality parameter structure in a geographic framework in the United States of America (USA) consisting of stream network, wa...

A review of the Nearctic genus Prostoia (Ricker) (Plecoptera, Nemouridae), with the description of a new species and a surprising range extension for P. hallasi Kondratieff & Kirchner

Abstract The Nearctic genus Prostoia (Plecoptera: Nemouridae) is reviewed. Prostoia ozarkensis sp. n. is described from the male and female adult stages mainly from the Interior Highland region encompassing portions of Arkansas, Missouri, and Oklahoma. Prostoia ozarkensis sp. n. appears most closely related to two species, one distributed broadly across the western Nearctic region, P. besametsa (Ricker), and one found widely throughout the central and eastern Nearctic regions, P. completa (Walker). A surprising range extension is noted for P. hallasi Kondratieff & Kirchner, a species once known only from the Great Dismal Swamp, from small upland streams in southern Illinois. Additional new state records are documented for P. besametsa, P. completa, P. hallasi and P. similis (Hagen). Taxonomic keys to Prostoia males and females are provided, and scanning electron micrographs of adult genitalia of all species are given.