Nectar inhabiting yeasts are commonly found in many plant species. Even though these microorganisms are abundant, much is still unknown about the communities of these microorganisms within and among plant species as well as the diversity of these microorganisms within and among seasons. This study examines the presence and diversity of these microorganisms in the dioecious plant species Silene latifolia as well as coflowering plants in Virginia, U.S. The majority of previous research on nectarivorous yeasts has been on hermaphroditic plant species. This is one of the few studies examining a dioecious plant species. Yeast species were isolated from the floral nectar of S. latifolia and associated plant species in 1999–2001, morphotyped into 37 morphospecies, and identified into 26 operational taxonomic units (OTUs) by sequencing the D1/D2 domain of the large subunit nrDNA. Yeast species from ascomycetes and basidiomycetes were isolated from nectar, including nectar associated ascomycetous Metschnikowia species and the basidiomycetous anther smut Microbotryum violaceum; however, ascomycetes dominated the samples. Metschnikowia species only accounted for 21% of the yeast isolates, a much lower percentage than in other studies. There was evidence of both host specificity and widespread dispersal of yeast species with Microbotryum violaceum found in nectar from both healthy and consistently diseased plant populations, indicating long distance dispersal of this fungus. There were no consistent differences among the sexes of S. latifolia, but male floral nectar appeared to have a higher diversity and species richness in some years. There was some indication of seasonality of yeast abundance in nectar as well as differences among years, potentially due to drought conditions. These results support the current body of evidence by researchers that, although not diverse in terms of the number of different yeast species found in nectar, yeasts are abundant in the nectar of plants.

Local adaptation of plant flower and life-history characters has often been studied in the context of specialized pollinators that vary in frequency or behavior among sites. Recently, the potential importance of herbivores and the interactions of pollinators and herbivores have also been recognized. We studied pollinators, herbivores, and plant phenotypes in four populations of the western wallflower (Erysimum capitatum, Brassicaceae) along an elevational gradient in the Front Range of the Eastern Slope of the Colorado Rocky Mountains in 2005 and 2006. Several phenotypic characters varied among populations over a small spatial scale (<50km), and plants were visited by a wide variety of pollinators and herbivores. E. capitatum plants in these populations were primarily pollinated by bees, pollen beetles, and flies. The most common types of pollinating visitors differed among populations. Ants were the most common visitors in all populations. They removed nectar from the base of flowers, occasionally attacked bees, and rarely came into contact with stigmas. Many other herbivores fed on flowers and buds of E. capitatum. Some of these damaged petals, potentially making plants less attractive to pollinators. Gall midge larvae (Cecidomyiidae) formed galls from flower buds and typically prevented flowers from opening. Both herbivores and pollinators were different from year to year and from population to population. We argue that the potential for local adaptation to pollinators and herbivores exists in Erysimum capitatum.

We studied the floral biology, floral visitors, levels of florivory, and mating system of Opuntia macrocentra in a population of ca. 300 individuals in order to describe what factors affect flower/fruit ratios. Blooming for the species occurred once a year during spring. Flowers were hermaphroditic, produced nectar, and remained open 6 to 9 h during a single day. Anther dehiscence starts at flower aperture and stigma receptivity starts approximately 1 h later. The most important floral visitors were solitary bees from the Anthophoridae family (genus Diadasia). Open- pollinated control and cross pollination treatments had the highest fruit set (96.8 ± 3.2% and 83.9 ± 6.7%, respectively), but fruit set for forced self-pollination treatment (77.4 ± 7.6%) did not differ from the cross-pollination treatment. Seed production was also highest in the open-pollinated treatment; the average number of seeds per fruit in the open-pollinated treatment was 40% higher than the cross-pollinated treatment and 64% higher than the self-pollinated treatment. The flowers were self-compatible and did not require a visitor to set fruit. Flower/fruit ratio was slightly above one over all pollination treatments (fruit ratios between 1.0–1.3), suggesting that almost all flowers turned into fruits. Outcrossing rates suggest a mixed mating system, but inbreeding depression was found for both fruit and seed set. Developing fruits were consumed by the caterpillar (Lepidoptera: Olycella subumbrella) and decreased fruit set from 20% to 100%. Florivory and inbreeding depression were the major factors that decrease fruit set for this species.

A large wetland drainage project was initiated in 1912 near the town of Seney, Michigan, U.S.A. This project included the construction of a series of ditches through a large peatland to drain the land for agricultural use. The largest of these ditches was the 35 km long Walsh Ditch. Much of the drained wetland affected by the Walsh Ditch is now managed by the U.S. Fish and Wildlife Service as part of Seney National Wildlife Refuge. Between 2002–2003, nine large earthen ditch plugs were installed along a 4.5 km section of the ditch in an attempt to restore the hydrological and ecological integrity of the approximately 1400 ha of wetlands and streams. This study explores the effects that the ditch plugs had on the hydrology and vegetation structure of the adjacent landscape 8y later. Plot level measurements (707 m² plots) of hydrology and vegetation, combined with an analysis of land cover change using aerial imagery, indicated that the ditch plugs had been successful in altering the hydrology and vegetation over portions of the area. Mortality of upland tree species more typical of xeric conditions and colonization by typical wetland species indicated that these sites should continue to develop into wetland ecosystems. Land cover change analysis showed an increase in wetland area of 152 ha. The areas of change were concentrated near the plugged ditch and near a large anthropogenic pool.

Anuran monitoring has increased in recent years in response to global population declines. Delineating abiotic factors that influence anuran activity patterns is important for maximizing monitoring and research efficiency. The Houston toad (Bufo (Anaxyrus)houstonensis) was the first amphibian to be listed as federally endangered in the United States, and populations have continued to decline since it was listed. In this study we investigated the influence of six abiotic factors and one biotic factor on Houston toad calling activity and terrestrial movement in the Lost Pines ecoregion of Texas. Using program PRESENCE, we treated the factors as survey-specific covariates to determine their influence on detection probabilities, and thus presumably activity levels. We found that average daily absolute humidity, average daily wind speed, and presence/absence of Houston toad calling activity the previous night were important factors influencing calling activity, and average daily absolute humidity and detection/non-detection of Houston toad movement activity the previous night were important factors influencing movement activity. We also found that multiple survey years were necessary to delineate influential factors for this species, a result with implications for activity patterns of other rare anurans. The results of this study contribute to our understanding of amphibian activity patterns, and will improve the efficiency of future Houston toad research and monitoring efforts.

Drought is an ecological challenge for turtle species worldwide and can be exacerbated by habitat fragmentation and loss, especially for small populations. We studied the activity of 16 Blanding's turtles Emydoidea blandingii using radio-telemetry from 2005–2006 during consecutive drought and normal hydrological years at a fragmented preserve in northeastern Illinois, U.S.A. The preserve experienced drought conditions during 2005 with precipitation levels 20% below the 60 y average. Fine scale measures of activity (i.e., mean water depth at locations, proportion of unique locations, and proportion of locations in dry habitat) differed between years, whereas broad scale measures of activity (i.e., home range, movement distance) did not. On average only 41.3% of 2005 home ranges overlapped with 2006 home ranges suggesting space use shifted between years. Although most proportional habitat use remained unchanged between years, several individuals increased their use of riverine habitats when other wetland habitat dried. Our study underscores the need to examine the risks of severe environmental events on vulnerable populations.

Telemetry is an extremely useful technique used to study movement patterns of fishes to gain insight into life history. This is especially important when dealing with species of conservation concern, such as the alligator gar (Atractosteus spatula). Alligator gar, despite dwindling populations or presumed extirpation across much of its native range, have received minimal attention in the literature. This study sought to evaluate movement patterns of juvenile alligator gar reintroduced to a historic, now disconnected, floodplain of the Mississippi River. Nineteen alligator gar fitted with radio transmitters were stocked into Mingo National Wildlife Refuge during May 2007 and tracked for 1 y. Over the course of the evaluation, 34.9 (se  =  5.1) locations per individual gar were recorded and three distinct movement patterns emerged. Thirteen alligator gar (Groups A and B) exhibited site fidelity throughout the study while five alligator gar (Group C) showed highly variable movement patterns; at times showing site fidelity, then exhibiting long-distance movements. When exhibiting site fidelity, alligator gar occupied small areas of Monopoly Marsh or Ditch 5 (Group A: 12.9 ± 6.0 ha, Group B: 4.8 ± 4.9 ha, Group C: 11.8 ± 8.0 ha). Our study demonstrated telemetry of juvenile alligator gar is feasible, various movement patterns (i.e., site fidelity or long-distance movement) exist, and future stockings of juvenile alligator gar are likely to show site fidelity to the area in which they are released.

Introduced crayfishes represent a serious threat to the endangered aquatic fauna of North America and Europe. We used small-scale competition assay experiments to examine competitive hierarchies in the laboratory between male and female Orconectes rusticus and Orconectes illinoiensis, Orconectes indianensis, and Orconectes placidus from southern Illinois. These species are considered threatened in Illinois and there is a potential for O. rusticus to become established in drainages inhabited by these species. Using sex and size-matched laboratory competition trials for a limited food resource, we found that both male and female O. rusticus were competitively dominant to O. placidus, O. illinoiensis and O. indianensis (P < 0.05). Male O. placidus, O. illinoiensis, and O. indianensis displayed no competitive hierarchies (P > 0.05). Female O. placidus were, however, competitively dominant to O. illinoiensis which was dominant to O. indianensis (P < 0.05). These simple laboratory competition experiments have been used to explore competition hierarchies involved in both North American and European crayfish invasions to understand observed and potential invasion success. These experiments, although presenting only one small aspect of the many mechanisms involved in the invasion and displacement of a resident species, can aid in predicting the potential effects of introduced species prior to an introduction. Our work indicates that the invasion of O. rusticus could have negative consequences for native crayfish species in southern Illinois.

In 1998, after 160 y without documented nesting, Double-crested Cormorants (Phalacrocorax auritus) recolonized Leech Lake, Minnesota. Competition for nesting space with the state threatened Common Tern (Sterna hirundo), and concern regarding potential walleye (Sander vitreus) and yellow perch (Perca flavescens) population declines prompted culling of cormorants and research into their diet. Stomach contents of adult and subadult cormorants were collected in 2004, 2005, and 2006 (186, 356 and 348, respectively) and from cormorant chick regurgitants in 2005 and 2006 (151 and 114, respectively). Perca flavescens (>70% composition and biomass) and shiner species (Notropis sp.) (>4% composition and biomass) were the main components of subadult and adult cormorant diets in 2004 and 2005 and the diet of chicks in 2005. However in 2006, whitefish species (Coregonus sp.) was the majority of percent biomass consumed by subadults and adults (43.4%) and a large proportion of percent biomass consumed by chicks (17.8%). In 2006 percent biomass of Corengonus sp. was different from other years for adults and subadults (P < 0.001) and chicks (P < 0.01) and may have been a product of a warming event die-off in late summer. All eight of the select common prey species varied (P < 0.01) in percent biomass between at least one of the ten delineated periods within 2004, 2005, or 2006. Differential prey selection by adults for self-feeding and provisioning for chicks was detected in Coregonus sp. (P < 0.01). While the diet of Leech Lake cormorants mainly consists of small abundant fish (P. flavescens and Notropis sp.), cormorant diet can vary within and among years. This study represents the first description of the diet of cormorants from a midwestern location other than the Great Lakes and reinforces the importance of site specific diet assessment, as the particular abundant prey species differs between locations.

The Rainwater Basin in Nebraska has been a historic staging area for midcontinent greater white-fronted geese (Anser albifrons frontalis) since the 1950s and, in the mid-1990s, millions of midcontinent lesser snow geese (Chen caerulescens caerulescens) expanded their spring migration route to include this region. In response to speculation that snow geese may be in direct competition with white-fronted geese, we compared staging ecology by quantifying diet, habitat use, movement patterns, and time budgets during springs 1998–1999. Collected white-fronted geese (n  =  190) and snow geese (n  =  203) consumed primarily corn (Zea mays; 97–98% aggregate dry mass) while staging in Nebraska; thus, diet overlap was nearly complete. Both species used cornfields most frequently during the morning (54–55%) and wetlands more during the afternoon (51–65%). When found grouped together, snow goose abundance was greater than white-fronted goose abundance by an average of 57 times (se  =  11, n  =  131 groups) in crop fields and 28 times (se  =  9, n  =  84 groups) in wetlands. Snow geese and white-fronted geese flew similar distances between roosting and feeding sites, leaving and returning to wetland roost sties at similar times in mornings and afternoons. Overlap in habitat-specific time budgets was high; resting was the most common behavior on wetlands, and foraging was a common behavior in fields. We observed 111 interspecific agonistic interactions while observing white-fronted and snow geese. White-fronted geese initiated and dominated more interactions with other waterfowl species than did snow geese (32 vs. 14%). Certain aspects of spring-staging niches (i.e., diet, habitat use, movement patterns, and habitat-specific behavior) of white-fronted and snow geese overlapped greatly at this mid-latitude staging site, creating opportunity for potential food- and habitat-based competition between species. Snow geese did not consistently dominate interactions with white-fronted geese; yet large differences in their numbers coupled with high degrees of spatial, temporal, and ecological overlap support potential for exploitative competition during years when waste corn may be in short supply and dry years when few wetlands are available for staging waterfowl.

The golden-cheeked warbler (Setophaga chrysoparia) and the black-and-white warbler (Mniotilta varia) breed in the deciduous/evergreen woodlands of central Texas. The golden-cheeked warbler is endemic, while for the geographically widespread, black-and-white warbler, these woodlands represent the southwestern terminus of the breeding range. To estimate relative abundance and to compare habitat associations, we estimated occupancy, corrected for probability of detection, for both species using replicated point-count surveys of 36 survey stations at each of six sites within the Balcones Canyonlands Preserve Travis Co. TX. Model selection using an a priori, set of candidate models suggested that the probability of detection differed among warbler species and study sites and both species were influenced by time of season, time of day, and habitat characteristics of the survey station—slope and canopy cover. Naïve occupancy estimates suggested that occupancy of black-and-white warblers was much lower than golden-cheeked warblers. However model-averaged estimates of occupancy corrected for imperfect detection suggested that occupancy of black-and-white warblers averaged across all study sites and survey stations were comparable to golden-cheeked warblers. For both black-and-white and golden-cheeked warblers occupancy was positively influenced by slope and this relationship was modulated by canopy cover. Our study provides an example of how occupancy modeling can change naïve perceptions of the relative abundance of species and be used to predict habitat associations of animals through point-count surveys while accounting for imperfect detection.

Eastern bluebird (Sialia sialis) populations are increasing across most of the species' range; however, we document a decline in a bluebird population in central Kentucky, where state and local Christmas Bird Count and Breeding Bird Survey data indicate bluebirds are declining throughout the Ohio River valley region. We examined several possible hypotheses for this decline, including habitat loss, nest cavity loss, increased competition from other species, and variation in winter temperature using long term nesting data gathered at one study site in central Kentucky. We found that bluebird abundance was positively correlated with mean temperature during the previous winter. Our data suggest bluebirds in central Kentucky are declining because they are susceptible to cold winters and are experiencing increased nest box competition.

We took nine skull measurements, three body measurements, and body mass on 240 eastern moles (Scalopus aquaticus) to determine age and sex-related morphologic variation. We estimated age of specimens as juveniles (<1 y old) or adults 1 to 4 y old based on wear of the last upper molar. Mean values for all skull and body measurements were significantly larger for males than females. There were significant age-related differences in body mass, total length, and width across the upper canines. Adult sex ratios differed seasonally, although not during the breeding season as expected; the sex ratio of 74 juveniles was 1∶1. We also investigated the correlation between age estimation based on wear of M³ vs. degree of ossification of maxillary bone over the buccal roots of the cheek teeth used in previous studies. We found little relationship between the two age estimation methods, with buccal ossification less precise than molar wear.

The role of carnivores in seed dispersal has only recently been studied in North American plants. We investigated the potential effectiveness of the Coyote (Canis latrans) as a seed disperser for American Persimmon (Diospyros virginiana; Ebenaceae) and tested the effect of experimental design in gut passage experiments. Germination percentage and rate and vigor of seedlings produced by D. virginiana seeds collected from Coyote scat were compared to seeds removed from or contained in whole fruit in a common garden experiment. Germination percentages for Coyote ingested seeds and whole fruit were nearly the same. Emergence was significantly faster for seedlings produced from ingested seeds compared to those seeds in whole fruit, however the quality of these seedlings was significantly poorer. Seedlings produced by seeds artificially removed from fruits had greater survival than those resulting from seeds ingested by coyotes or contained in intact fruits. Our results suggest that Coyotes can effectively disperse D. virginiana,but whether the positive aspects of dispersal outweigh the negative effects of gut passage remains an open question. Our experimental results indicate that these two species have not coevolved, as expected, since the range of Coyotes has only recently overlapped substantially with that of D. virginiana.

Black-footed ferrets typically prey upon prairie dogs at night while prairie dogs are presumably sleeping. Prairie dogs can act aggressively towards aboveground ferrets in daylight and we observed prairie dog aggression towards ferrets four times in South Dakota and Montana. Ten behaviors by prairie dogs were recorded during aggressive interactions with ferrets including chasing, blocking, and physical contact. One of the aggressive prairie dogs was confirmed as an adult male and three of four encounters occurred Jun. through Jul. Interactions lasted <10 min and neither the prairie dog nor ferret were visibly injured.

During a 2008 study to assess endocrine and reproductive health of common carp (Cyprinus carpio) in Lake Mead, Nevada (U.S.A.) we identified two fish, one male and one female, as hybrids with goldfish (Carassius auratus) based on morphology, lateral line scale count, and lack of anterior barbels. Gross examination of the female hybrid ovaries indicated presence of vitellogenic ovarian follicles; whereas histological evaluation of the male hybrid testes showed lobule-like structures with open lumens but without germ cells, suggesting it was sterile. Because common carp/goldfish hybrids are more susceptible to gonadal tumors and may have different endocrine profiles than common carp, researchers using common carp as a model for endocrine/reproductive studies should be aware of the possible presence of hybrids.