There has been strong recent interest in the “macroecological” approach of explaining local community phenomena as a consequence of patterns at larger geographic scales. Various authors have suggested that if local observations can be explained by the larger-scale patterns in which they are embedded, there is less need to invoke local (within-site) processes (like competition, habitat structure, etc.) to explain community structure. We used a large database on local stream fish assemblages and species distributions in the Interior Highlands of Arkansas to test three macroecological hypotheses: (1) faunal similarities among upland river basins can be predicted from the hierarchical geographical connectivities of those streams in the larger Mississippi River Basin drainage network; (2) faunal richness of drainages up to the size of small rivers (ca. 4000 km²) increases with drainage area; and (3) local (within-site) species richness increases in proportion to regional (basin) richness. These hypotheses were tested at the level of “all species”, and within the families Cyprinidae (minnows) and Percidae (darters). For the first hypothesis, Mantel tests comparing matrices of faunal similarities and basin connectivity (based on number of nodes separating these smaller basins within the Mississippi River Basin) showed that similarities in composition of fish faunas among the upland basins were predictable from the pattern of drainage connectivity. This pattern existed at the levels of “all species”, minnows, and darters. Upland basins separated by the fewest nodes had fish faunas that were most similar, with all basins in the more northern White-Arkansas river basin separating (across all taxa and within families) from the southern Ouachita river basin drainages; and lesser rivers within these basins also showed similarity generally related to their connectivity. In tests of the second hypothesis, drainages up to small rivers in size exhibited positive, species-areas slopes at all taxonomic levels. Species-area regression slopes (z) were 0.30 for “all species”, and 0.36 for darters, both differing significantly from a slope of zero. However, minnows had a species-area regression slope of z = 0.20, which did not differ statistically (P = 0.16) from a slope of zero. For the third hypothesis, regional (basin) species richness explained little of the variation in species richness at individual local sites, with the relationship significant at P = 0.054 for mean local number of “all species”, and nonsignificant within the minnow and darter families. Within all levels of regional (basin) species richness, there was great variation in number of species found at individual sites. Overall, we conclude that extrinsic macroecological hypotheses, based on patterns at large spatial scales, differed in explaining composition of the faunas or assemblages at smaller spatial scales, leaving much variation in local assemblage structure to be explained by local intrinsic factors.

Optimal foraging theory predicts that when prey density is low, predators should employ a generalist feeding strategy and take prey in proportion to their abundance. The purpose of this study was to compare the diet of common nighthawks (Chordeiles minor: Caprimulgidae) with a measure of prey abundance. Relative to the proportion of insects available, nighthawks consumed Coleoptera and Hymenoptera more than expected while Diptera were avoided. Only Trichoptera and Lepidoptera were consumed in proportion to their abundance. A qualitative comparison of our results with data on nighthawk diets from the Okanagan Valley, British Columbia, suggests that the birds in the two locations have different diets but similar preferences relative to the abundance of different insect orders.

During 1994–1995, we saw 70 species of birds on the Buffalo Ridge Wind Resource Area. In both years bird abundance peaked in spring. Red-winged blackbirds (Agelaius phoeniceus), mallards (Anas platyrhynchos), common grackles (Quiscalus quiscula), and barn swallows (Hirundo rustica) were the species most commonly seen. Most birds (82–84%) flew above or below the height range of wind turbine blades (22–55 m). The Buffalo Ridge Wind Resource Area poses little threat to resident or migrating birds at its current operating level.

Tame birds have been used for ecological field studies, but rarely are birds >8 wk old used. To our knowledge, no previous study has successfully released and monitored tame ruffed grouse (Bonasa umbellus) >14 wk old. We report here the techniques used to raise ruffed grouse from eggs collected in the wild and from pen-reared birds to obtain tame birds up to 1.5 yr old that were released and monitored in the wild. Birds were raised with either intensive imprinting (10–24 h/day of human contact) or nonintensive imprinting (<2 h/day of human contact) during the 1st 7–8 wk after hatching. We released 10 ruffed grouse, one at a time, in southern Illinois during the winters of 1990 and 1991. The first four birds released were killed by predators within 1 wk, but allowed us to modify our observation techniques to reduce the stress on released birds and maintain their tameness. Of the remaining six birds, five (four juvenile, one adult) were released in clear-cuts in the Shawnee National Forest, Union County, Illinois, and successfully monitored from February to April 1990 and November 1990 to March 1991. We were equally successful in releasing and observing ruffed grouse that were intensively and nonintensively imprinted, suggesting that long hours of contact with young birds are not necessary to obtain observable birds in the wild. Time-activity budgets, habitat use and forage selection of the tame birds were also similar to those reported for wild ruffed grouse. We believe that the use of tame birds is a feasible method for collecting data on ruffed grouse ecology and may be used to evaluate forage and habitat quality where introductions are proposed or to be evaluated.

This study determined that inexpensive and easily maintained amphibians and exotic fishes could act as hosts for two species of native North American unionid mussels, and bypass the need to identify native hosts when the object is to culture mussels. Two mussel species, Lampsilis cardium and Utterbackia imbecillis, were used to parasitize 42 exotic fishes and seven potential nonpiscine host species. Nonpiscine hosts included amphibians and decapod crustaceans. Lampsilis cardium successfully metamorphosed on six species of exotic fishes, as well as on larval tiger salamanders. Utterbackia imbecillis successfully metamorphosed on 30 species of exotic fishes and all four amphibian species tested. No glochidia metamorphosed on crustaceans. Successful metamorphosis on amphibians indicates that mussel zoogeography may be more complicated than previously thought. Using surrogate hosts may be a valuable alternative to natural hosts in laboratory culture of mussels.

The ants Formica podzolica, Myrmica fracticornis and M. incompleta commonly build nests in a large peatland complex in N-central Montana. Nests of Formica are much larger than those of Myrmica spp. and occur in a microtopographic mosaic of hummocks and hollows. The large mound nests of F. podzolica and the hummocks are similar in size, and both had elevated levels of K, PO₄⁻, Mg and Na compared to the peatland surface, suggesting that the hummocks are abandoned ant mounds. Ant mounds provide an environment for plants that has better aeration and is warmer as well as nutrient-enriched. A few species of strongly rhizomatous graminoids occur on active mounds, but abandoned nests (hummocks) provide habitat for larger shrubs as well as many species of plants that otherwise could not grow in the cold, nearly saturated peat. Formica workers obtain much of their nutrition by tending aphids that feed on the shrubs growing on hummocks. We hypothesize that this is a positive feedback relationship that has promoted the increase of Formica colonies and allowed them to permanently change the structure and composition of a large portion of the vegetation in this rich fen.

We examined sexual size dimorphism (SSD) and growth rates in samples of bog turtles (Clemmys muhlenbergii) from North Carolina, Pennsylvania and New Jersey. Mean carapace length (CL) of males was significantly greater than mean CL of females in all three states. However, the degree of SSD varied significantly among states. Specimens from North Carolina had the greatest SSD, the largest mean adult CL, and the largest mean hatchling CL. Growth rates were rapid until about age 6 and a CL of 80 mm. Males grew faster than females thereafter. A comparison of the three parameters estimated from von Bertalanffy growth equations showed significant differences for asymptotes between sexes and states for the North Carolina and Pennsylvania samples, but not for the growth rate constant (parameter k). Geographic variation in SSD appears to be a result of differences in growth related to the timing of maturity and the approach to asymptotic body size caused by indeterminate growth, or both. We suggest that male-biased SSD in this species is ultimately a consequence of the advantage conferred to larger males in male-male interactions and during mating.

I examined capture rates of invertebrate prey by pitchers of the purple pitcher plant Sarracenia purpurea, in western Newfoundland, Canada. While captures were diverse, Hymenoptera (mostly ants), Coleoptera and Gastropoda accounted for 69% of the total dry mass caught. Gastropoda decompose quickly and completely in pitchers, and their importance (20%) implies that prey sampling methods that do not survey freshly caught prey may seriously underestimate resource availability in pitchers.

The average pitcher caught 11 mg dry mass of animal biomass over its lifetime, but capture rates were highly variable (range 0–67 mg). Pitchers opening earlier in the season caught no more or less than those opening late. Larger pitchers caught more than smaller ones, although size accounted for a small fraction of total variance. Capture rates changed with time, peaking in pitchers 12–33 days old; however, pitchers continued to catch prey through their 2nd season (i.e., after overwintering). In an average pitcher, 2nd-season captures made up nearly half of the total.

We examined the structural and spatial distribution of woody biomass in relationship to disturbance in an Indiana old-growth deciduous forest over a 66-yr period. Analysis was done on the core 7.92 ha of a 20.6-ha forest in which every tree 10 cm dbh and over has been tagged and mapped since 1926. Five years are compared—1926, 1976, 1981, 1986 and 1992. Dry weight of living biomass for the 7.92-ha area for these 5 yr was 154 Mg/ha, 207 Mg/ha, 220 Mg/ha, 216 Mg/ha and 211 Mg/ha, respectively. Biomass of dead trees was 1 Mg ha⁻¹ yr⁻¹ from 1977 through 1981; 4 Mg ha⁻¹ yr⁻¹ from 1982 through 1986; and 3 Mg ha⁻¹ yr⁻¹ from 1987 through 1992. Biomass of trees that died between 1976 and 1992 was greatest for midseral species. Living biomass of dominant early to midseral species is declining while that of late seral species is increasing. In 1926 biomass of trees 10 to 25 cm diam consisted of 14% Quercus spp. and 12% Acer saccharum. By 1992 biomass in this diameter range consisted of 1% Quercus spp. and 43% A. saccharum.

Equilibrium patch size was estimated for biomass at each of the five inventory dates to determine if there was a change. Equilibrium patch size for biomass was estimated to be 0.64 ha during all five inventory dates based on the coefficient of variation (CV) of biomass for 16 different grid cell sizes. Grid cell size refers to the size of adjacent cells in a grid that covered the entire study area. The grid with the smallest cells had cells of 0.01 ha. This grid of 0.01-ha cells was aggregated to 15 additional grid cell sizes, where the largest grid cell size was 1.98 ha. CV for all grid cell sizes was highest in 1926 due to effects of prior grazing.

These data indicate an increase in deadwood biomass, a shift in stand composition, recovery from grazing by an increase in small diameter trees and no change in equilibrium patch size over the five inventory dates.

The reproductive activities of Sorex vagrans and S. cinereus in western Montana were documented using histological methods. Testicular recrudescence in both species began in February with maximal development and spermatogenesis attained by late March to early April and testicular activity was maintained well into the autumn. Breeding began in late April and extended into August in S. vagrans; no conceptions were documented past June in S. cinereus. Estimated parturition dates peaked in May for S. vagrans and in June for S. cinereus. Average litter sizes in utero for both species were consistent with previously reported values for populations at similar latitudes. Both species exhibit similar breeding patterns in sympatry.

Growth, reproduction, circulation, and thermoregulation in domestic livestock and laboratory rodents are adversely affected by consumption of tissues derived from plants infected with endophytic fungi. Because little is known about the systemic effects of infected diets on wild rodent granivores, we conducted a series of laboratory experiments to assess the effects of consuming endophyte-infected (E ) and uninfected (E−) seeds of tall fescue (Festuca arundinacea) on reproduction in the white-footed mouse, Peromyscus leucopus. Groups of mice (paired and single-sex) were fed diets of either rodent chow, E , or E− seeds; in several experiments, chow and seeds were ground and mixed in a 1:1 ratio. E− seeds alone suppressed reproductive output compared to chow-fed mice, but consumption of E seeds did not further reduce reproductive performance. Furthermore, paired testes mass was more strongly reduced by the presence of seeds in the diet than was the mass of the female reproductive tract, but reproductive tract mass in both sexes was not further diminished by endophyte consumption. These results suggest that males are more sensitive than females to the presence of seed in the diet, and that white-footed mice and related rodent granivores cannot rely upon a diet of grass seeds alone to support reproduction. Depending upon the time of year that such seeds are eaten, suppression of breeding may be advantageous to consumers.

Juvenile nine-banded armadillos (Dasypus novemcinctus) discriminate between the scents of siblings and nonsiblings, spending more time near and investigating more often the scent of a sibling. In the present experiment we examined whether the ability to make such distinctions generates behavioral differences in how juveniles interact with one another. Two juveniles (siblings or nonsiblings) were placed in an arena and the ensuing interactions were videotaped. Contrary to expectation, juvenile armadillos showed no evidence of behavioral discrimination between siblings and nonsiblings. All interactions were highly amicable and aggressive behavior was almost completely absent. The absence of behavioral discrimination between juvenile armadillos may be due to (1) the lack of an appropriate context for discrimination in our experiments; (2) ontogenetic considerations such that only older animals actually exhibit discrimination, or (3) low genetic variability in our population that makes discrimination less important.

We characterized 131 summer, diurnal bed sites of 26 elk (11 bulls and 15 cows) in Custer State Park, South Dakota, from 5 June–30 August 1994, 1995 and 1996. Overstory canopy closure, number and basal area of trees, percent litter and bare ground were greater (P < 0.05) at bed sites than at random plots. North aspects were selected (P < 0.05). Microsite air temperature and percent of grass were lower (P < 0.05) at bed sites than at random plots. Hiding cover, wind speed, percent of forbs, shrubs, rocks, and wood, slope percent, average tree dbh, elevation, distance to roads, distance to trails, and distance to water were not different between bed sites and random plots (P > 0.05). Trees were present at 128/131 (97.7%) of bed sites (0.01 ha square plot), but occurred on only 41.2% (54/131) of random plots. An average summer, diurnal elk bed site had basal area >12.4 m²/ha, >110 trees/ha, >54% canopy closure on N aspects. Overstory canopy closure, tree basal area and microsite temperature correctly classified 86.2% of the observations, suggesting thermoregulatory factors influenced CSP elk use of summer, diurnal bed sites. Although elk are successful in some unforested areas despite the lack of suitable thermal cover, our data suggest that elk in the Black Hills prefer relief sites that provide thermal bed sites when available during the summer diurnal period. Management of appropriate thermal cover should be maintained in areas in which it exists.

We collected culled forewings of moths from 26 feeding roosts to determine the species of moths consumed by the Virginia big-eared bat (Corynorhinus townsendii virginianus) in eastern Kentucky in June, July and August 1992. Feeding roosts were located in cliffs adjacent to two maternity and one bachelor roosts. A total of 45 species of moths were identified from 222 forewings collected, representing six families: Noctuidae (n = 139), Sphingidae (n = 41), Geometridae (n = 24), Notodontidae (n = 13), Thyatiridae (n = 3) and Lymantriidae (n = 2). Length of forewings collected ranged from 1.3–4.1 cm. The majority (77.8%) of species of moths eaten by C. t. virginianus develop from larvae dependent on forest plant species.

Anther-smut disease caused by Ustilago violacea is transmitted by insects that visit diseased flowers and then deposit spores on healthy Silene alba plants. The transmission rate of this disease therefore depends on spore deposition by the vector species and preferences for infected vs. healthy hosts. We observed natural populations of S. alba to document the most abundant insect visitors, which include syrphid flies, andrenid bees, bumblebees and a variety of nocturnal moths. Using bumblebees and moths in flower preference studies, we showed that bumblebees preferentially visited healthy flowers, but the strength of this preference declined if the bees had prior exposure to diseased flowers. Nocturnal moths showed less discrimination with respect to disease status when plants were arranged in a field population of S. alba, and preferentially visited plants with more flowers. A laboratory analysis of spore deposition by bumblebees showed that whereas most spores were deposited on the first several flowers visited, flowers beyond the 15th visit may still receive enough spores to produce a new infection. Spore deposition was also influenced by changes in vector behavior associated with spacing in artificial arrays of S. alba plants. Models were fitted to deposition data to compare estimates for spore dispersal rates and the initial number of spores acquired by vectors. This study demonstrated several ways that vector behavior can influence rates of disease spread in natural populations. Preferences for healthy vs. infected hosts can cause disease dispersal to vary from that expected by randomly foraging insect vectors. Changes in visitation behavior associated with host density can affect the magnitude and distance of spore deposition in host populations.

The distribution and abundance of amphibians and reptiles in forest stands subjected to salvage cutting and prescribed burning were compared with their unmanaged counterparts. The study was conducted on the Atlantic coastal plain at Chesapeake Farms near Chestertown, Maryland. Three herpetofaunal trapping arrays were systematically located in each of four forest stand types: hardwood (Hardwood), cut-over hardwood (Cut), mixed pine-hardwood (Pine) and prescribed burn pine (Burn). A total of 3931 individuals representing 29 species were captured in 30,540 trap nights during the spring and summer 1992 and 1993. Felling of hardwoods and prescribed burning of pine resulted in similar responses from the herpetofaunal communitites; Hardwood had the most distinctive herpetofaunal community of the four stands. Adults and young-of-the-year (YOY) of six amphibian species were significantly more abundant in Hardwood than Cut. Only one amphibian species, Pseudacris triseriata, was less abundant in Hardwood than Cut. Total ranid captures did not differ between Hardwood and Cut. Snake and total reptile captures, and Elaphe obsoleta and Eumeces faciatus abundances were significantly less in Hardwood than Cut. Hardwood also had fewer small mammals than Cut, particularly Microtus pennsylvanicus and Zapus hudsonius, that might serve as prey for large snakes. Adults of four amphibian species, YOY of five amphibian species, and three reptiles (Carphophis amoenus, Storeria dekayi and Thamnophis sirtalis) were significantly more abundant in Pine than Burn; two reptile species (Coluber constrictor and Lampropeltis getula) were significantly less abundant. Potential small mammal prey of the latter two snakes were not significantly different between Pine and Burn; however, Zapus hudsonius was less abundant in Pine than in Burn. More amphibians were captured in Hardwood and Pine stands than in their respective logged and burned counterparts. The trend for reptiles tended to depend on the mix of species present and their habitat preferences. Greater canopy cover and depth of leaf litter in Hardwood and Pine stands likely had a moderating effect on temperature and helped to maintain a moist microenvironment for mesophilic species. Disturbance of a small patch of forest could locally decrease herpetofaunal diversity, but diversity on a much larger scale would likely increase.

We document the first known occurrences of the cotton mouse (Peromyscus gossypinus) in Illinois since 1909. Mean hind foot length and body mass of cotton mice from study areas in two counties were significantly greater than sympatric white-footed mice (P. leucopus). The cotton mice occurred in forested bottomland habitat.

In Cartier Creek, a small stream in southeastern Ontario, larvae of the chironomid Nanocladius branchicolus Saether were found associated symphoretically with nymphs of the damselfly Argia moesta (Hagen). This is the first report of a symphoretic association involving A. moesta; however, N. branchicolus was previously found associated symphoretically with nymphs of stoneflies in the families Perlidae and Pteronarcyidae. The attachment site of the chironomid was most frequently along the abdomen and metathorax of the host, although occasionally they were attached to the prothorax or gill lamellae. Approximately 22% of the population of A. moesta harboured symphoretic chironomids. Lake-outflow streams provide important habitat requirements of N. branchicolus. The benefits to N. branchicolus of a symphoretic habit may include increased stability in fast currents, reduced energy expenditure for relocation, reduced interspecific competition for food and a superior pupation site.