Ely Kosnicki

Factors Influencing Stream Fish Species Composition and Functional Properties at Multiple Spatial Scales in the Sand Hills of the Southeastern United States

AbstractAn understanding of how fish communities differ among river basin, watershed, and stream reach spatial scales and the factors that influence these differences can help in the design of effective conservation programs and the development of reference models that appropriately represent biota under relatively undisturbed conditions. We assessed the heterogeneity among fish assemblages in first- to fourth-order stream sites from four river basins (Savannah, Chattahoochee, Cape Fear, and Pee Dee rivers) within the Sand Hills ecoregion of the southeastern USA and compared it with the heterogeneity associated with watershed and stream reach spatial scales. Fifty-five species of fish representing 15 families were collected by electrofishing, with the most speciose families being Cyprinidae, Centrarchidae, Percidae, Ictaluridae, and Catostomidae. Constrained ordination identified clearly demarcated species assemblages among river basins as well as subbasin environmental variables that affected fish specie...

The influence of soil type, congeneric cues, and floodplain connectivity on the local distribution of the devil crayfish (Cambarus diogenes Girard)

Abstract.  Burrowing crayfish are potentially important ecological links between terrestrial and aquatic systems, but little is known about what drives their local distribution patterns. We investigated potential mechanisms underlying the patchy local distribution of the devil crayfish (Cambarus diogenes Girard) in a stream floodplain ecosystem of the coastal plain of Alabama. We used a series of field surveys and laboratory trials to: 1) quantify local distributions and soil-type associations, 2) identify soil preferences of juveniles and adults, 3) examine the effects of biotic (adult occupancy) and abiotic (soil compaction) factors on juvenile burrowing preferences, and 4) investigate the role of floodplain connectivity on burrow density. Juvenile crayfish were more abundant in sandy streamside soils, whereas adults were more abundant in clay-based floodplain soils. In laboratory preference trials in artificial burrowing chambers, adults and juveniles showed affinity for floodplain over streamside soils, a result suggesting that factors other than soil preference influence field patterns. When juveniles were presented with situations where adults were established, they initiated burrows in association with the adult burrows regardless of soil type. Soil compaction did not influence juvenile burrowing preference, but did result in smaller burrows in laboratory trials. Adult burrow density in the floodplain was negatively related to stream bank angle and top-of-bank height. Juvenile C. diogenes took longer to climb banks with high bank angles than those with low bank angles, a result suggesting increased risk of predation and desiccation associated with disconnected floodplain conditions. Local distribution of C. diogenes burrows in stream/floodplain systems appears to be a product of interacting physical and biological factors rather than of soil-type preferences. Stream–floodplain connectivity may affect recruitment and population viability of burrowing crayfish.

First Nearctic Records of Oliveiriella Wiedenbrug and Fittkau, with New Distributional Records for Two Other New World Species of Orthocladiinae (Diptera: Chironomidae)

ABSTRACT: Taxonomic and distributional information need to be constantly updated as federal, state, and local agencies continue to use aquatic macroinvertebrates as biological indicators of water quality. While processing benthic macroinvertebrate samples provided by federal and state agencies, production taxonomists at EcoAnalysts, Inc. encountered larvae and pupae of the Neotropical chironomid Oliveiriella Wiedenbrug and Fittkau (Orthocladiinae) and Onconeura semifimbriata (Sæther) (Orthocladiinae) from sites in New Mexico and Arizona, USA. These occurrences represent the first Nearctic records of Oliveiriella, establishing a New World distribution, and expand the Nearctic range of Onconeura semifimbriata. We also identified larvae of Tempisquitoneura merrillorum Epler (Orthocladiinae) from 1 site in Nevada, 1 site in Utah, and 6 sites in Arizona, USA. These records expand the Nearctic range for T. merrillorum. These genera are very similar in appearance to other commonly encountered Orthocladiinae genera, but only the larva of Tempisquitoneura is included in a current taxonomic key for North America.

Development of an Index of Biotic Integrity for the Sand Hills Ecoregion of the Southeastern United States

AbstractWe developed an index of biotic integrity (IBI) for the Sand Hills ecoregion within the upper Coastal Plain of the southeastern United States. This ecoregion exhibits differences in species composition among river basins and possesses a relatively depauperate fish fauna that has been affected by faunal homogenization. We also investigated whether this IBI could be improved by adding benthic macroinvertebrate information. Data collected from 70 wadeable stream sites were used to calculate 45 fish assemblage metrics. Twelve metrics within the categories of species richness, species composition, habitat guild, trophic guild, tolerance level, alien/invasive species, and individual fish condition were retained after screening all metrics for sensitivity to disturbance, redundancy, and ecological content. Heterogeneity of species composition among basins led to a greater reliance on richness, indicator species, trophic guild, and habitat guild metrics rather than on more geographically variable species ...

A Stream Multimetric Macroinvertebrate Index (MMI) for the Sand Hills Ecoregion of the Southeastern Plains, USA

A macroinvertebrate multimetric index is an effective tool for assessing the biological integrity of streams. However, data collected under a single protocol may not be available for an entire region. We sampled macroinvertebrates from the full extent of the Sand Hills ecoregion Level IV of the Southeastern Plains with a standard protocol during the summers of 2010–2012. We evaluated the performance of 94 metrics through a series of screening criteria and built 48 macroinvertebrate multimetric indexs with combinations of the best performing metrics, representing richness, habit, functional feeding guild, sensitivity, and community composition. A series of narrative-response tests for each macroinvertebrate multimetric index was used to find the best performing macroinvertebrate multimetric index which we called the Sand Hills macroinvertebrate multimetric index. The Sand Hills macroinvertebrate multimetric index consisted of the measures Biotic Index, % Shredder taxa, Clinger taxa2/total taxa, Plecoptera and Trichoptera richness, and Tanytarsini taxa2/Chironomidae taxa. Comparison of the Sand Hills macroinvertebrate multimetric index with existing assessment tools calculated with our data indicated that the Sand Hills macroinvertebrate multimetric index performs at a high level with regard to identifying degraded sites and in its response to stress gradients.

Missouri State Record for Polypedilum (Pentapedilum) Tritum Walker (Diptera: Chironomidae) Based on Larval Identifications from Wadeable Streams

INTRODUCTION Polypedilum (Pentapedilum) tritum (Walker) has a widespread Holarctic dis tribution (Stone et al., 1965; Oliver et al., 1990; Caldwell et al., 1997; Oyewo and Saether, 2008). However, Epler (2001) noted the name P. tritum may represent more than one species in the southeastern USA. We identified larvae of P. tritum in samples collected from 27 of 224 wadeable streams sampled in Missouri during the years 2008-2010. Streams where specimens of P. tritum were collected were sampled during 28 March and 16 to 18 September, 2008, 31 March and 1 April, 2009, and 23 March to 6 April, 2010 in the Osage Plains, Ozark Highlands, and Central Dissected Till Plains ecological sections of Missouri (Cleland et al., 1997; Nigh and Schroeder 2002) (Fig. 1). Our records of P. tritum represent the first for this species in Missouri, although larvae of this species may have been misidentified as members of the Polypedilum illinoense group in earlier collections. The undeveloped posterior lobe in the ventromental plates, antennae with vestigial Lauterborn organs and long segments 3 and 4, and the sunken first lateral teeth of the mentum should be a unique set of characters to distinguish larvae of P. tritum from larvae of other described species (for full description see Oyewo and Saether, 2008). However, there are 52 recognized species in the subgenus Pentapedilum, but only 11 of those have larval descriptions (Oyewo and Saether, 2008). Although undescribed larvae of some Polypedilum species may, possibly, have characteristics in common with some diagnostic characteristics of larval P. tritum, we are confident in our identifications of lar val P. tritum based upon the description for larvae of this species provided by Oyewo and Saether (2008). Volume 122, Number 2, March and April 2011 165