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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.

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.

Rivers, representing the primary conduits of dissolved inorganic carbon (DIC) from the continents to the oceans, are important components to the global carbon cycle. To better understand the complex carbon cycling dynamics within two nested, mixed lithology watersheds, two sites were studied along the karst influenced upper Green River in south‐central Kentucky, USA. Weekly samples were collected from June 2013 through May 2014 and analyzed for δ13CDIC. The mixing model IsoSource was employed to better understand source partitioning differences over seasonal time spans and across the two nested basins. In both the lithologically mixed upstream basin (53% carbonate rocks, 47% siliciclastic) and carbonate rock dominated downstream basin (96% carbonate rocks in the drainage area between Greensburg and Munfordville, 78% in the total area upstream from Munfordville), DIC was primarily derived from soil respiration. The proportion of DIC from dissolved carbonate minerals derived from the downstream carbonate rock dominated basin was similar to the upstream basin, due to carbonate mineral dissolution having such a consistent effect on the overall DIC content of the river. Seasonally, soil respiration provided the most DIC from fall to winter. Early spring precipitation, combined with limited seasonal photosynthesis, shifted groundwater to be the primary source of DIC, bringing in a flush of carbonate mineral‐rich water during higher flows. This study provides insight into carbon dynamics across multiple lithologies and the important influence of seasonality using carbon isotope sourcing to determine carbonate mineral dissolution variability and aid in understanding its contribution to global carbon flux quantification. Copyright © 2015 John Wiley & Sons, Ltd.

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact support@jstor.org.. The University of Notre Dame is collaborating with JSTOR to digitize, preserve and extend access to American Midland Naturalist.ABSTRACT.-The processing of black cherry (Prunus serotina) leaf packs was studied during the summer of 1992 in two streams, Linesville Creek (LC) and Powdermill Run (PMR). The streams differed considerably in: (1) summer macroinvertebrate (shredder) fauna; (2) thermal regime, and (3) streamside riparian flora. Except for one species (Brilliaflavifrons), LC lacked shredders, whereas PMR supported numerous shredder populations during the summer months. Fast-and medium-processed leaf material dominated the LC riparian zone whereas slow-processed leaf material was nearly absent. In contrast, the PMR riparian assemblage was well-represented in each processing category. Leaf packs were processed, as loss of dry mass, in near-equal rates using either days or degree-days as an independent variable. Gathering-collectors (e.g., Polypedilum spp.) and shredders (Tallaperla maria) dominated macroinvertebrate abundance and biomass colonizing the LC and PMR packs, respectively. Our results suggest that: (1) gathering-collectors (e.g., Polypedilum spp.) may compensate for the reduced abundance of shredding detritivores in processing of summer leaf detritus and (2) the absence of slow-processed riparian foliage in small woodland streams (e.g., LC) may prevent the establishment of a spring-summer shredder fauna.