Etheostoma zonale was collected from the Hocking River in south-central Ohio from April 1999 through August 2001. Ovaries of adult females were classified by developmental stage and appropriate-stage ovaries were used to analyze clutch size, egg size and gonadosomatic index (GSI). Although body condition was significantly low in 1999, we saw no direct evidence for a correlation with any reproductive trait in that year. Clutch size varied among years, though not in parallel with condition. Etheostoma zonale produced larger clutches and had larger GSI toward the middle of the breeding season in each year. Egg size declined over the season in each year. The amount of intraseasonal variation in reproductive traits here was similar to that previously reported for interannual and geographic variation in E. zonale and should caution investigators from generalizing from limited collections during the breeding season.

Generalist predators, such as spiders, play an important role as natural enemies in agroecosystems and, given the annual disturbance of most field crops, these predators typically re-colonize fields from adjacent habitats such as hedgerows or riparian forests. To test whether the biota of these source habitats differed, we collected ground-dwelling spiders (Araneae) from thin (<15 m) riparian forests, wide (>50 m) riparian forests and hedgerows (<15 m wide) located next to soybean or corn fields in south-west Ohio. Pitfall traps collected spiders at the stream edge, the interior of forests or hedgerows and the agricultural edge. Rarefaction analysis and non-metric multidimensional scaling (NMDS) ordination tested how spider diversity and community structure, respectively, differed between hedgerows and riparian forests and by trap location. Wide riparian forests harbored a higher diversity of spiders than thin riparian forests and hedgerows contained the lowest spider diversity. The latter result may be due in part to the invasive honeysuckle shrub Lonicera maackii in hedgerows, which can reduce habitat complexity on the ground-layer. Ordination analysis revealed the spider community found at the edge of hedgerows is distinct from other trap locations, as was the spider assemblage located adjacent to the stream, the latter containing some hygrophilous species. The spider fauna at the edge of hedgerows contained several species typically found in high densities in agricultural plots, supporting the need for these habitat features in an agricultural landscape.

Information is needed on protected furbearer communities to help understand the ecological impacts of trapping pressure on furbearer populations. We monitored coyotes (Canis latrans), bobcats (Lynx rufus), raccoons (Procyon lotor) and opossums (Didelphis virginiana) from October 1995 to March 2000 in northeastern Kansas to determine survival and cause-specific mortality of a furbearer community protected from trapping. Annual survival did not differ among years or between sexes for all species, but seasonal differences occurred for coyotes, raccoons and opossums. For coyotes, deaths from humans resulted in decreased survival in winter compared to summer. For raccoons and opossums, deaths from coyote predation resulted in decreased survival in winter compared to summer. Annual survival rates of coyotes (0.71), bobcats (0.77) and raccoons (0.71) were similar to those reported from lightly exploited populations. Annual survival of opossums (0.06) appeared to be extremely low although survival of opossums was not reported in previous studies. The wide-ranging movements of coyotes and bobcats took them off the protected area and made them susceptible to anthropogenic mortalities (80% and 83% of deaths, respectively). In contrast, coyote predation accounted for 40% and 76% of raccoon and opossum deaths, respectively. The high density of coyotes (0.8–0.9 coyotes km²) on the protected area likely contributed to the high predation rates on raccoons and opossums.

Parasites have been identified as potential threats to mammalian carnivores, particularly insular species. We evaluated external parasites on island spotted skunks (Spilogale gracilis amphiala), a threatened insular endemic carnivore on Santa Cruz and Santa Rosa Islands of the California Channel Islands (USA). We identified fleas (Pulex irritans, Nosopsyllus fasciatus), lice (Neotrichodectes mephitidis) and ticks (Ixodes pacificus, I. kingi). Results suggest potential host-switching by ectoparasites among the native and introduced fauna on the islands, possibly due to the paucity of both potential hosts and ectoparasite species. Sharing of ectoparasites enhances the possibility of disease transmission between carnivores via ectoparasite vectors.

We examined collection of scats (feces) as a survey method for indexing statewide populations of swift foxes (Vulpes velox). We searched for scats on 99 transects throughout the range of swift foxes in New Mexico. Swift fox scats were found on 79.8% of transects. Scats confirmed by DNA analysis to have originated from swift foxes were found on 59.6% of transects. Statistical power was sufficient to detect a 20% decline in the proportion of transects with swift fox scats or a 7% decline in the total number of scats collected over the entire range. The proportion of transects with scats and the total number of scats collected may be useful as indices of relative swift fox population abundance. Average number of scats found per collection site was not found to be a useful index due to large variations between sites in the numbers of scats found. Confirmation of swift fox presence by DNA analysis does not appear to be necessary for transects with >7 scats, as all transects with >7 scats had at least one confirmed swift fox scat. Collection of scats appears to be a useful technique for indexing populations of swift foxes in New Mexico.

A series of experiments was conducted to examine the effects of competition on allometry and defense using tomato plants (Lycopersicon esculentum). No mortality occurred over the 4-wk test period, even with a plant density of 30 plants per 10-cm². However, allometric patterns for log canopy diameter vs. log height indicated that competition occurred as early as 8 d after transplant and for pots with as few as two young plants (density of about 2 plants per 10-cm²). There was a change towards less root mass for greater height as competition increased. Leaf concentration of the allelochemicals chlorogenic acid, rutin and tomatine increased with decreasing competition, with the sum of these exhibiting a sigmoid-like pattern for allelochemical concentration. But competition did not affect leaf proteinase inhibitor activity, or petiole glandular trichomes or total trichomes. While the results are compatible with the growth-differentiation balance (GDB) hypothesis, they also indicate some of the difficulties that will be encountered in testing the GDB hypothesis rigorously.

We studied the ramet dynamics of Chapman's goldenrod [Solidago odora var. chapmanii (A. Gray) Cronquist] in burned Florida scrub and sandhill by monitoring permanent quadrats for 10 y, excavating to reveal clonal structure and postfire responses and taking extensive notes on the plant's life history. Chapman's goldenrod was attacked by a wide variety of herbivores and grazing mammals. However, leaf damage from herbivores and pathogens was relatively minor. This rhizomatous perennial forb produced conspicuous flowering displays after fires. Censuses in 23 permanent quadrats set out after 12 fires revealed that the density and size of goldenrod ramets declined over the years following fire. Densities dropped most rapidly in the first few years following fire and declined more slowly in formerly grazed areas than in ungrazed Florida scrub. Season of burn did not influence subsequent ramet dynamics. Flowering was concentrated during the first 2 y after fires. Repeated burns produced a rebound in ramet densities, flowering and ramet sizes. Excavations revealed that several clones (or clone fragments) could intermingle within a square meter quadrat. Seedling recruitment was patchy and most postfire increases in ramet numbers were due to resprouting and short-distance clonal spread. In combining resprouting, clonal spread and seedling recruitment, Chapman's goldenrod differs from most other Florida upland herbs that simply resprout or depend on seedling recruitment to recover after fires. Between fires, this species persists as suppressed ramets (a persistent bud bank). The combination of postfire stimulation of growth and flowering, with persistence between fires (also found in shrubs in Florida scrub), may be adaptive in ecosystems where fire return intervals are highly variable.

Many studies to date have documented clear energetic costs and benefits of avian roost selection. Male Common Nighthawks (Chordeiles minor) spend at least half of each day during the summer on a day-roost. Therefore selection of roost-sites likely has implications for survival and long-term fitness. Our objective was to identify characteristics of day-roosts used by male Common Nighthawks in Cypress Hills Provincial Park, Saskatchewan, Canada. We measured features of roost trees and monitored behavior of roosting birds. Nighthawks preferred trees situated on north facing slopes surrounded by trees with significantly lower canopy height compared to randomly measured trees. Roost trees were taller than random trees and occurred in less dense patches of forest. Birds always roosted parallel to branches and adopted a motionless posture. There was a non-significant trend for birds to roost on branches facing east. Birds typically roosted in a direction pointing away from the sun and away from the roost tree trunk. Roost trees emerging from the canopy may provide landmarks for birds as they search for suitable day-roosts, whereas a low tree density surrounding roost trees likely reduces flight costs associated with maneuvering. Our results suggest that roosts chosen by male nighthawks may provide selective benefits in terms of microclimate, energetics and predator avoidance, but further studies are needed to determine which is the most important.

We tested the hypothesis that female prairie vole (Microtus ochrogaster) residents change their space use patterns in response to immigration pressure. We established prairie vole populations in four 32 × 32-m enclosures during 2000 and 2001. Four populations were supplemented with adult female immigrants and the other four served as control populations in which no females were introduced. Using radio-telemetry, we monitored and compared the home ranges and movement distances of residents vs. immigrants within the same enclosures and residents in enclosures with and without immigrants. Immigrants had significantly larger home ranges and moved greater distances during the evening hours than residents. Resident home ranges and hourly movements were unaffected by the presence of immigrants. The results suggested that resident females could successfully defend their territories without changes in their home ranges and movement distances. However, due to our experimental design, we could not exclude the possibility that female immigrants affected the space use of male residents.

Adult greater redhorse Moxostoma valenciennesi, were seined from the Grand River, Ontario, and artificially spawned in May 1997 and May 1998. Eggs hatched after 6–8 d at a mean temperature of 19 C. Eggs and larval development of 9–22-mm specimens are described. Ontogeny of larval greater redhorse was compared to that of other syntopic Moxostoma species from previously published studies, including river redhorse (M. carinatum), black redhorse (M. duquesnei), golden redhorse (M. erythrurum), shorthead redhorse (M. macrolepidotum), copper redhorse (M. hubbsi) and spotted sucker (Minytrema melanops). There was significant overlap between most meristic variables that were compared. However, the majority of greater redhorse (up to 18-mm) have myomere counts (27–33 pre-anal myomeres, 9–10 postanal myomeres and 39–42 total myomeres) that are different from other sympatric redhorse species and spotted suckers and may allow identification of greater redhorse as small as 9-mm.

Florida scrub grows on relict beach ridges with xeric sands, which are constantly transported by wind and water. These sand movements are likely affect microsites occupied by Florida scrub herbs and their demography. We analyzed temporal variation in sand accretion and erosion in natural post-fire gaps within the shrub matrix and along sand roads at Archbold Biological Station in five time intervals: 1 and 2 wk and 1, 3 and 6 mo. Also, in three experiments, we tested effects of sand movements on three herbaceous scrub species: Balduina angustifolia, Paronychia chartacea and Polygonella basiramia. In two pot experiments we studied: (1) seedling emergence from seeds buried to 0, 5 and 20 mm sand depths and (2): seedling survival with (a) frequent but shallow burial by sand, (b) alternating sand addition and removal and (c) infrequent deep sand addition vs. (d) control. Finally, in a field experiment, we studied plant rosette and flowering stem growth with (a) sand addition, (b) sand removal, (c) alternating sand addition and removal, (d) controls protected from spontaneous sand movements and (e) non-manipulated controls. Sand accretion and erosion fluctuated over time with sand erosion greater than accretion. With increasing time intervals, the range of oscillations increased. Sand erosion was significantly greater and more variable along roads than in natural gaps. In the pot experiments, significantly more seedlings emerged from shallower depths. Seedling survival with experimental complete burial was lower than in other treatments. In the field experiment, plants responded to sand removal by significant elongation of flowering stems. The three studied species differed in seedling emergence and growth responses to treatments. The demographic responses of the species to sand movements indicate that mobile sands create constantly shifting arrays of microsites that can influence post-dispersal seed germination, survival and growth of Florida scrub herbs. Roadside habitats have more dynamic patterns of sand movements than natural gaps and may alter selection regimes important for demographic variation of endemic Florida scrub plants.

We used a mark-recapture method and model averaging to estimate apparent survival, recruitment and rate of population growth in a native freshwater mussel population at a site on the Cacapon River, which is a tributary to the Potomac River. Over 2200 Elliptio complanata, E. fisheriana and Lampsilis cariosa were uniquely tagged over a period of 4 y. Recapture probabilities were higher in spring and summer than in winter except for L. cariosa which had a low probability of recapture regardless of time of year. All three species had high annual adult survival rates (>90%) with lower estimated survival of small (≤55 mm) mussels (43%–69%). The variation in apparent survival over time was similar for all three species. This suggests that whatever environmental variables affect survival of mussels in this site affected all three species the same. Recruitment rates were low (1–4%) for both E. complanata and L. cariosa, with E. fisheriana having several periods of high (15–23%) recruitment. Distribution within the site was affected by both downstream and upstream movement, though movement rates were generally <1%. Average population growth rates for E. complanata (λ = 0.996, se = 0.053), L. cariosa (λ = 0.993, se = 0.076) and E. fisheriana (λ = 1.084, se = 0.276) indicated static populations. Population growth rate approximating 1.0 suggests this site supports a stable freshwater mussel population through a life history strategy of low but constant recruitment and high annual adult survival.

Recent studies of stream fish assemblages have begun to incorporate landscape properties in explaining the dynamics seen at individual sites in riverine systems. In this approach, stream and river landscapes (riverscapes) are viewed over greater spatial and temporal scales to understand the dynamics seen at individuals sites. Adventitious streams are feeder tributaries of mainstreams at least three orders greater in magnitude. Interface sites between adventitious streams and their mainstreams are often more diverse and variable than either the feeder stream or mainstream alone. We analyzed fish assemblage data from 21 sites over three periods (1967, 1995 and 2001) from an adventitious stream drainage (Piasa Creek: Jersey, Madison and Macoupin CO., IL) to test the hypothesis that assemblage variability and diversity would be greater at downstream interface sites than those further upstream. There was a correlation between distance from the mouth of the stream and assemblage variability over time, as well as a negative correlation between distance from the mouth of the stream and mean diveristy over time. We hypothesize that the observed patters in community variability and the distribution of some species within the drainage are best explained by the interactions between the big river fauna and the stream fauna.

We evaluated the effect of dietary fat on body fat of meadow voles (Microtus pennsylvanicus) in the field after a 6-wk supplemental feeding period with a 25% dietary-fat food. The initial 3-wk period showed no difference in body composition, but, after 6-wk, 33% of captures showed body fat exceeding 10%, levels atypical of wild populations. Fattening levels found with supplemental food were similar to body fat levels seen in lab-reared or wild animals removed and kept under lab conditions. Our results suggest that the lean body composition found in wild populations is influenced strongly by high-fiber and low dietary-fat forage, along with other environmental constraints. When provided easily available and abundant high dietary-fat food in the wild, a higher percentage of individuals increased body fat to levels rarely seen under natural conditions.

Mesopredator populations are increasing because of habitat fragmentation and elimination of keystone predators. An increase of mesopredators, such as the raccoon (Procyon lotor) and Virginia opossum (Didelphis virginiana), may change competitive interactions within the trophic level of medium-sized carnivores and omnivores. We conducted live-trapping during 1998–2001 in north-central Oklahoma and compared population parameters of opossums living in areas with and without reduction of raccoons during 2000–2001. The equivalent of 6.2 raccoons/km² was removed from the treatment area. Capture rates of opossums were higher in the non-removal area for most of the study period, but population estimates and density did not vary by treatment. Survival rates of opossums varied by sex and season, but not by treatment according to modeling of opossum survival. Habitat partitioning, prey switching by opossum predators, food supply, study scale, and environmental and demographic stochasticity may have masked effects of interspecific competition on population dynamics of opossums on the study site.

Two scientific names referring to the sand shiner have appeared in the literature during the past decade. A ruling by the International Commission on Zoological Nomenclature in 2002 (Opinion, 1991) conserved the more commonly used name, Notropis stramineus (Cope, 1865), and this name should be used rather than the name N. ludibundus (Girard, 1856).

A total of 48 adults Pacific fat sleepers Dormitator latifrons was collected from Tres Palos Lagoon, Guerrero, Mexico, between May and August 1999. Seven helminth taxa were recovered: Clinostomum complanatum, Pseudoacanthostomum panamense, Saccocoelioides sp., Neoechinorhynchus golvani, Contracaecum sp., Cosmocerca podicipinus and Gnathostoma sp. All of the Pacific fat sleepers were infected. Mean species richness and mean helminth abundance were 2.4 and 143.6, respectively. Helminth infracommunity diversity was low (with a Brillouin's value of 0.6), reflecting the high proportion of the sample dominated by N. golvani (48%) as well as the larger number of metacercariae of P. panamense. These characteristics were similar to those previously observed in other brackish water fishes. Three essential factors determine the helminth infracommunity of D. latifrons: diet, feeding behavior and vagility of the host. Additionally, the composition of helminth fauna is also influenced by the oligohaline condition of the lagoon (4 of 7 species have freshwater origin).

The potential for ecological and economic damage caused by invasive species is only beginning to be appreciated. A recently arrived, and particularly worrisome, invader in North America is the Asian longhorned beetle Anoplophora glabripennis (Motschulsky), the larvae of which damage trees and forests. The geographic extent and likely path of its possible invasion of North American forests, however, are unknown. Herein, we develop and test ecological niche models for the species based on features of climate from the species' native distribution in eastern Asia, and then project them onto North America to identify areas of potential distribution. These models suggest that the species has the potential to invade much of eastern North America, but only limited areas in western North America, and that a focus of initiation of invasions is likely to lie in the area south of the Great Lakes. This result is particularly clear under modeled scenarios of spread and contagion.

In the last decade the invasion of European earthworms into previously worm-free glaciated areas of North America has stimulated research into their impacts on native forest ecosystems in the region. As a first approximation, the impacts of invading earthworms are related to their biomass. However, direct measurements of biomass can be significantly affected by the moisture conditions under which the earthworms are collected and their relative gut contents. Ash-free dry mass is the best standardized measure of earthworm biomass, but requires the destruction of specimens. This paper presents five allometric equations that allow for estimation of ash-free dry biomass based on length (mm) measurements for European earthworm species (Lumbricidae) commonly seen in the United States.

We evaluated partitioning of food resources among syntopic eastern red (Lasiurus borealis), Seminole (L. seminolus) and evening (Nycticeius humeralis) bats at the Savannah River Site, South Carolina, from June through August of 1996 and 1997. We compared diets to indices of relative prey availability, which were based on samples of the insect communities in bat foraging habitats and the amounts of time the bats foraged in each habitat. The relative proportions of insect orders consumed differed among the species. We recorded only minor differences between insect consumption and indices of prey availability, as assessed by insect light traps placed within foraging habitats. Our data suggest that Eastern red bats and evening bats altered their prey selection late in the summer.

Edge effects on grassland-nesting birds should be less pronounced or absent near cropland edges of grasslands that lack wooded-edge habitat often used by nest predators and brood parasites. We compared nest predation, brood parasitism and densities of dickcissel (Spiza americana) nests in relation to distance from woodland and cropland edges of Kansas tallgrass prairie. Daily nest predation rates did not differ (P > 0.25) among distance intervals (≤50 m, 51–100 m, ≤100 m and >100 m) from either edge type or among 50-m intervals adjacent to each edge type. Brood parasitism rates by the brown-headed cowbird (Molothrus ater) were higher ≤100 m vs. >100 m from woodland edges (P = 0.04), being highest ≤50 m from woodland edges (P = 0.09). Parasitism rates were not related to distance from cropland edges, although parasitism rates ≤50 m from woodland and cropland edges were statistically similar (P = 0.16). Dickcissel nest densities were lower ≤50 m from woodland edges relative to farther distance intervals (P = 0.004), indicating dickcissel avoidance of this edge type. There was no similar pattern of nest density on cropland-edged sites, but nest densities ≤50 m from woodland and cropland edges were statistically similar (P = 0.17). Thus, some woodland edge effects on this grassland bird species were apparent but might vary geographically.