Plastome sequences have been used successfully at lower and lower taxonomic levels. Our findings corroborate earlier works, suggesting that there are regions that are most likely to be the most variable. However, while NC-cpDNA sequences are commonly used in plant phylogeographic studies, few of the most variable regions are applied in that context. Furthermore, it appears that in most studies too few NC-cpDNAs are used to access the discriminating power of the cpDNA genome.

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Benthic macroinvertebrates and sediments were sampled in second-to fourth-order Tennessee Ridge and Valley streams and evaluated relative to urban land use and natural riparian cover. Site-specific estimates of EPT family richness (number of Ephemeroptera, Plecoptera, and Trichoptera families) ranged from 3 to 15. Urban land use in the watershed (from < 1 to 27 %) was directly correlated with total suspended solids, sediment coverage, sediment depth, and oligochaete abundance. Watershed urban land use was inversely correlated with EPT family richness and relative abundances of EPT, filterers, and predators. Riparian forest cover was inversely correlated with total suspended solids, and total plant/wetland cover in the buffer was directly correlated with overall invertebrate taxa richness. Although natural riparian features appeared to have a positive influence on stream habitat quality and biotic conditions, correlations were stronger at the catchment scale. Relationships observed in this study underscore the negative effects of increased watershed urbanization on environmental conditions (more sedimentation) and benthic invertebrate assemblages (fewer pollution-sensitive insects, filterers, and predators) in small to midsize streams.

An economic impact study was conducted in 1990 to determine the regional economic impact of the Lake Texoma sportfishery. Lake Texoma, a 36,000‐hectare impoundment of the Red River on the Oklahoma‐Texas border, is nationally recognized for its striped bass (Morone saxatilis) fishery. Angler expenditures were estimated using data from mail, telephone, and roving creel surveys. The IMPLAN (IMpact Analysis for PLANning) modelling system was used to evaluate the effect of fishing expenditures on the regional economy (seven counties bordering the reservoir). In 1990, Lake Texoma anglers contributed an estimated $25.641 million in fishing expenditures to the regional economy. An economic impact analysis indicated that angler expenditures were directly associated with $13.56 million in value added (personal income plus indirect business taxes) and 417 jobs in the impact region. Potential impacts (considering indirect and induced effects) of angler expenditures included up to $57.392 million in total business sales; $23.273 million in value added; and 718 jobs. Nonregional anglers visiting the reservoir to fish for striped bass accounted for 77% of the total expenditures. Factors that influence striped bass fishing activity on Lake Texoma (e.g., habitat alterations, management actions) could have substantial effects on the regional economy.

The upper watershed of North Chickamauga Creek (NCC), a fourth-order tributary to the Tennessee River, Tennessee, has been impacted by decades of acid mine drainage (AMD) from abandoned coal mines. We assessed fish assemblages, pH, conductivity, and sediment coverage at 12 study reaches (six AMD sites and six reference sites) in the Cumberland Plateau region of the NCC system, May-September 1998. Stream pH increased (3.6 to 6.0) and conductivity decreased (296 to 49 @/cm) downstream of the AMD-impacted area; however, no discernable gradient was observed in sediment cover. Elevated conductivity at AMD-impacted sites reflected increased concentrations of dissolved metals and other inorganic ions. Reference sites exhibited higher pH (6.0-6.4) and lower conductivity (13-28 pS/cm). Acidified reaches were characterized by low fish species richness (r = 0.885, P = 0.0007) and abundance (r = 0.854, P = 0.0017); no fish were observed at sites where the mean pH was 6. Centrarchids (mostly bluegill [Lepomis macrochirus] and green sunfish [L. cyanellus]) comprised >90 % of the catch at AMD sites, whereas cyprinids (creek chub [Semotilus atromaculatus] and blacknose dace [Rhinichthys atratulus]) accounted for >90 % of the catch at reference sites. Findings from this study document the negative effects of acid drainage from coal mines on fish assemblages in a Cumberland Plateau stream.