Effects of bridge and culvert construction or replacement were studied on 41 streams in Tennessee. One 100-m stream reach above and two 100-m reaches below were sampled at each bridge or culvert with a 50-m buffer zone separating each reach. Fish communities were sampled bi-annually for two years following single pass depletion techniques using a backpack electrofishing unit. Sediment depth and silt-clay percentages were measured during the spring at the upper end of each 100-m sampling reach. Sediment depth and percent silt-clay were greater at streams with culverts than at streams with bridges. Sediment depth and silt-clay percentages did not differ between structure and downstream transects for either bridges or culverts; but they were greater at structure transects than at upstream transects only on streams with culverts. Fish diversity, abundance, and richness did not differ between streams with bridges and streams with culverts, nor among sample reaches. Sediment characteristics and fish metrics were not correlated with bridge age in months.This study indicated that culverts, but not bridges, caused sediment accumulation. However, this accumulation was not sufficient to impact fish communities.

We examined the feasibility of implanting coded wire tags in several size‐classes (47–189 mm, total length) of channel catfish Ictalurus punctatus, bluegill Lepomis macrochirus, walleye Stizostedion vitreum, largemouth bass Micropterus salmoides, and golden shiner Notemigonus crysoleucas. Tags were implanted in three anatomical locations (nasal capsule, cheek musculature, or nape). Growth of tagged and untagged fish was not significantly different, and tag‐related mortalities ranged from 0 to 12% throughout the study. In 7 of 26 experiments, survival of tagged fish was significantly different from (usually lower than) survival of control fish (P < 0.05). After 6–9 months, tag retentions varied from 91 to 100%.

Species diversity and richness, relative abundance, and community structure were compared between simultaneous single-pass electrofishing and depletion sampling. Additionally, the number of fish displaced from sample reaches when not using block nets was estimated at each sample site. A total of 40 depletion samples was obtained during the spring and summer of 1999 and 2000 in small first-and second-order warmwater streams of central Tennessee; first passes were used as single-pass samples. Shannon-Wiener diversity values obtained with the single-pass approach were strongly correlated to those obtained with depletion sampling (r2 = 0.95). The same number of species was captured using both approaches in 15 of 40 streams; depletion sampling richness values exceeded single-pass values by more than two species in only one stream. Using bootstrap analyses, relative abundance values from single-pass samples differed from those of depletion samples in 2 1 of 40 streams. However, community structure comparisons using similarity indices (SIMI) indicated that the singlepass approach effectively sampled fish abundance. SIMI values were above 0.90 in 32 of 40 streams and above 0.75 in the other eight. Fish were displaced from sample reaches when not using block nets in 32 of 40 streams, but displaced fish species represented less than 10% of the total number of species in 29 of these streams. Fish movement from sampled reaches did not negatively affect estimates of diversity, richness, or relative abundance; the single-pass approach effectively sampled fish communities in these streams.

This study investigated spatial patterns and partitioning of fish community diversity in the Emory River basin, Tennessee, USA, which represents the best available biotic condition in a region characterized with high diversity and endemism. Fish community analyses were intended as one criterion for identifying aquatic conservation areas in a Habitat Conservation Plan (HCP) currently developed in the study region under the authority of the US Endangered Species Act. Spatial patterns of fish community diversity were examined at 57 stream sites located in the mainstem (13 sites) and four sub‐basins (a total of 44 sites) by partitioning γ diversity (total diversity) into α (within‐community) and β (among‐community) components in a multiplicative manner at two spatial scales. Additional analyses were conducted to assess evidence of dispersal in structuring local communities. Mainstem sites were characterized with higher α diversity values relative to sub‐basin sites, and γ diversity of 13 mainstem sites was comparable with that of 44 sub‐basin sites. Site‐level β diversity differed among sub‐basins. Among‐sub‐basin β diversity was only modest, and one sub‐basin harboured the majority of total species richness found among all sub‐basins. Many species had high indicator values for mainstem sites, but sub‐basin sites were associated with few indicator species. Spatial autcorrelation of fish community similarity was significant within mainstem sites and sites located within two sub‐basins. Catchment area explained among‐site variation in species richness better than stream order, link magnitude, confluence link or downstream link. Overall, there was a lack of evidence that dispersal played an important role in shaping local fish communities in either mainstem or sub‐basin sites. Aquatic conservation in the study basin should focus on protecting aquatic diversity in the mainstem habitat, while a network of stream sites in the most diverse sub‐basin may also be considered as aquatic conservation areas. Copyright © 2012 John Wiley & Sons, Ltd.

Nutritional and social challenges arising from habitat fragmentation can be significant sources of stress for animals. If prolonged, such stressors can pose a threat to the longevity of a species within a fragmented landscape. While each may elicit a physiological response, the coupled and often additive nature of these stressors can make it difficult to determine their relative impact on an individual or population. We measured fecal glucocorticoids (fGC) in two populations of Lemur catta, an endangered strepsirrhine primate, inhabiting forest fragments that vary markedly in resource structure and population density. We also examined the relative importance of behavioral variables indicative of feeding environment, intergroup territoriality, and intragroup social interactions in predicting fGC levels in these populations. Lemur catta living with ample food resources but at high population density exhibited higher fGC concentrations throughout the study period, independent of sex or reproductive state. At both sites, fGC levels reflected consistent seasonal variation, with lowest levels occurring during the resource-rich pre-mating period. Foraging effort was positively associated with fGC levels at each site, yet the population exhibiting the highest foraging effort had consistently lower levels of fGC. Intergroup territoriality was a positive predictor and intragroup agonism a negative predictor of fGC levels; however, trends in these variables were inconsistent when examining the two sites separately. Within-site group differences highlighted the additive nature of nutritional and social stressors in predicting fGC levels. Our results suggest that the intense or unpredictable impact of crowding and, correspondingly, heightened intergroup resource defense may be an important consideration when addressing long-term conservation initiatives for fragmentdwelling L. catta.