Herbaceous communities located within forest openings increase plant species diversity of forests in the Knobs Region of Kentucky. Although these grass-dominated communities are protected and managed for rare plant species conservation, it is unclear how soil conditions may delineate the grassland-forest boundary. We compared soil chemical and physical properties and soil nitrogen pools and transformations of three forest openings with those in the surrounding forest and the wooded edge separating the grassland and forest communities. Soil pH, extractable cations, bulk density and silt content were higher in openings compared to forest soils and extractable phosphorus was lower. In forest-opening grasslands, total soil nitrogen and the availability and production of plant-available N were 25 to 50% of levels in adjacent forest. Soils of the woody edge were similar to the surrounding forest. Our results suggest that the presence of these calcareous glade openings is highly correlated with edaphic conditions, so that efforts to expand rare plant habitat may be constrained by the distinct soils of these forest openings.

Mounds formed by pocket gophers (Geomys pinetis) in a longleaf pine—wiregrass savanna had larger daily soil temperature fluctuations than surrounding matrix locations. Microsite temperature differences persisted for more than a year, but were largest during summer months. Mound soil also had lower total carbon, total nitrogen, available ammonium, available phosphate and slightly lower soil moisture than matrix locations. These differences occurred in the context of an ecosystem where frequent fire consumes organic matter and removes herbaceous cover. The distinct microclimate and nutrient characteristics of gopher mounds did not significantly influence wiregrass germination, wiregrass seedling survival or longleaf pine seedling survival. Wiregrass germination and seedling survival in the first growing season was low and did not differ between mound and matrix locations. Longleaf pine seedling survival in the first growing season was 64–77% in the absence of fire, but no more than 15% in blocks that were burned. To see a relationship between mound microsite conditions and biotic response, it may be necessary to focus on microbes or turn to other ecosystems.

Native Monterey pine (Pinus radiata) forests occur in five populations on the west coast of North America. High severity fire has been reported to be the main disturbance agent that initiates seedling establishment for this species. To investigate the impacts of fire in this ecosystem, age structure and fire history data were collected from the native Año Nuevo Monterey pine forest near Santa Cruz, California. Stump cross-sections were removed from 10 randomly placed openings, and each was dated to determine tree age and fire history. Average mean fire return intervals were 11.2–20.1 y. Fifty-one percent of the Monterey pine trees in all openings regenerated within 5 y of three mixed severity fires. This was well below the predicted value of 75% that was based on the literature and life history characteristic of Monterey pine. A fire in 1948 produced the largest Monterey pine regeneration episode, and this fire was verified by written records. Monterey pine forests are multi-aged and have a great amount of spatial heterogeneity, attributes common in mixed severity fire regimes. Monterey pine has morphological characteristics of a fire evader and fire resistor and may be more appropriately classified in an intermediate category.

Goldenseal (Hydrastis canadensis L.) is an herbaceous perennial species that is becoming more rare within its range. Hydrastis canadensis populations are highly isolated and pollen flow between these populations may be restricted. I examined the breeding system of H. canadensis to determine if it may be limiting seed set due to increasing isolation of individuals and populations from one another. I tested fruit set in treatments designed to detect the presence of apomixis, passive autogamy, active autogamy, short distance outcrossing and long distance outcrossing. No fruit set occurred in flowers that were emasculated and bagged, suggesting the species is incapable of apomixis. However, low rates of fruit set were found in all other treatments, suggesting a mixed mating system in which both selfing and outcrossing may occur. Pollen transfer between highly isolated populations can result in fruit set, as can within-population pollen transfer. The breeding system type appears unlikely to be a major factor limiting the distribution or abundance of H. canadensis. However, overall low rates of fruit set may be important demographically.

The objective of the study was to collect, identify and document the presence of macrofungi occurring in the Black Hills of South Dakota and Bear Lodge Mountains of Wyoming. Two-hundred sixty species of macrofungi were collected from 95 sites in the Black Hills of South Dakota and Bear Lodge Mountains of Wyoming during 1998–2002. Two-hundred thirty-nine are submitted as new records for the area. Thirty percent of all species were collected only once during the study and 35% were collected from only one site. A total of 173 species were collected from five established permanent sites. All permanent sites were visited four times each summer during the study. Of species collected at permanent sites, 19% were collected only once at a site and 57% occurred at only one of the five sites. Twenty-five species (10%) were collected every year from one or more of all 95 sites and 10 species (6%) were collected every year from one or more of the five permanent sites.

Andropogon gerardii populations are comprised of two (or more) polyploid forms over much of the range of the species. To understand the impact of intraspecific polyploidy, polyploid cytotypes were compared over 4 y in native grasslands in Boulder, Colorado. Boulder A. gerardii populations averaged 59.6% hexaploids (60 chromosomes), 35.3% enneaploids (90 chromosomes) and 5.1% intermediate (aneuploid) chromosome numbers using flow cytometry to infer chromosome numbers. Neither mean clone area nor mean annual change in clone area differed significantly between ploidy levels. Hexaploid clones produced significantly more viable seeds than enneaploids. Enneaploids are not replacing themselves, whether that is measured absolutely or relative to hexaploids. Enneaploid reproductive effort was greater than hexaploid reproductive effort in some years and they produce substantial numbers of good seeds, but those seeds rarely have enneaploid cytotypes. The populations should eventually become entirely hexaploid. In the current populations, however, enneaploids are big, vigorous and fertile individuals.

Ecological trap theory suggests that greater predator activity occurs along edge habitat, thereby reducing prey abundance. Alternatively, environmental gradients associated with edge habitat may be responsible for changes in prey abundance irrespective of predator spatial distribution. To test these alternative hypotheses, I measured the distance soil arthropods were to edge of boxes (21 × 9.5 cm) placed on the forest floor of prairie (precipitation-limited; 1977–1999) and boreal forest (moderate precipitation; 2000–2001) sites. Predator theory predicted that in either environment predatory groups would be located close to edge and herbivore/detritivore groups would not be distributed different from random. In support of this hypothesis, in the precipitation-limited environment 7 of 11 soil arthropod groups were distributed as predicted; however, only 7 of 13 groups followed predator predictions in the moderate-precipitation environment. In support of the environmental gradient hypothesis, 22 of 24 soil arthropod groups were distributed as predicted. Here, all hard-bodied groups, with the exception of snails, were located closer to edge than expected and all soft-bodied groups, with the exception of slugs, were not located closer to edge than expected indicating possible avoidance of external dryness. Tests of these two hypotheses were confirmed with similar results using a regression method to determine if distribution declined from edge to interior. In conclusion, the results did not support the predation hypothesis and instead supported the environmental gradient hypothesis with moisture the likely explanation for the distribution pattern of soil arthropods.

The negative impacts of biological invasion are economically and ecologically significant and, while incompletely quantified, they are clearly substantial. Ants (family Formicidae) are an important, although often overlooked, component of many terrestrial ecosystems. Six species of ants are especially striking in their global ability to invade, and their impacts. This paper focuses on the impacts of the most destructive of those species, the red imported fire ant (Solenopsis invicta), and focuses on impacts on native vertebrates. Red imported fire ants often become the dominant ant species in infested areas outside of their native range due to their aggressive foraging behavior, high reproductive capability and lack of predators and/or other strong competitors. The evidence suggests that mammals, birds and herpetofauna are vulnerable to negative impacts from fire ants, and some species are more likely to experience negative population-level impacts than other species. Assessing the ecological impacts of fire ants on wild animal populations is logistically difficult, and very few studies have combined replicated experimental manipulation with adequate spatial (>10 ha) and temporal (>1 y) scale. Thus, most studies have been observational, opportunistic, small-scale or 'natural' experiments. However, significant research, including an increase in experimental and mechanistic investigations, has occurred during the past decade, and this has led to information that can lead to better management of potentially affected species.

Fishes present in 19 watersheds in New York are inventoried. One hundred seventy-six taxa (171 species) reside in these watersheds. Eighteen taxa are extra-limital exotic fishes, that is, they are not native to any New York watershed. The remaining 158 taxa are native in at least one New York watershed, although transfer of species among watersheds within the state is, and has been, widespread. Sixteen species are diadromous or estuarine and eight of these species support land-locked populations, so 150 taxa are strictly freshwater and native. Watersheds differed markedly in richness and composition. Over 100 taxa are reported from five watersheds and seven have fewer than 75 taxa. Twelve species are now extirpated from all New York watersheds and 28 other species have disappeared from at least one of their historic watersheds. Fifty-seven native species are infrequently caught, are considered rare and are candidates for special consideration. Within the state, patterns of species distribution are complex and are affected by environmental differences among the watersheds, the presence of suitable dispersal routes and widespread introductions.

We observed the behaviors in six fantail darter spawning events and produced a model describing the probability of any sequence of behaviors between an egg's deposition and its fertilization. Of the 12 different behaviors we observed, “quiver” and “rest” were the most common for both males and females. Courtship and spawning behaviors may be ritualized, as there was no apparent variation in how the behaviors were performed by different individuals. This could also result from a limited sample size. However, breeding pairs differed with respect to the order in which the behaviors were performed. In addition, we found that courtship behaviors occurred through all phases of the spawning events and that the largest males in the study were the only males to successfully mate with females.

In 1997 and 2000 we monitored nesting by diamondback terrapins daily from 1 May through 31 October at a beach on an island in northeastern Florida. During our visits we recorded and marked newly oviposited intact nests, monitored previously marked nests for depredation, hatching or washout and identified nest predators. We recorded nest deposition from late April through late July, but most nests were found in June (2000) or July (1997). Most nests were depredated within 48 h of oviposition. Most depredated nests were found in June or July, and those from July included both newly deposited and recently hatched nests. Depredated nests in August and September were all recently hatched. The major nest predators were raccoons, but we also noted crows, boat-tailed grackles, armadillos, ghost crabs and two species of plant roots. Hatching and emergence began in early July and continued into October. The mean emergence period for 54 nests was 68.9 d. In 1997, 21.9% of marked nests were washed out by high tides or storms and 8.9% suffered that fate in 2000.

We investigated the daily activity patterns of seven species of turtles in a northern Indiana lake over 10 y using the numbers of captures in fyke nets as an index of activity. Chrysemys picta and Graptemys geographica were active throughout the daylight hours. Sternotherus odoratus and Chelydra serpentina were crepuscular. Trachemys scripta was diurnal; however, its activity was concentrated in the morning hours. Apalone spinifera was diurnal as well, with most activity in the afternoon and very little in the morning. Emydoidea blandingii was rarely captured, and all captures were made during daytime hours. Activity patterns did not change substantially between two sampling periods from mid-May to mid-June and from late-July to early-August. These activity patterns are consistent with differences in the frequency of basking: baskers are diurnal (e.g., C. picta, G. geographica, T. scripta, E. blandingii and A. spinifera), whereas those that are secretive are crepuscular (e.g., S. odoratus and C. serpentina).

Cottonwood (Populus deltoides) woodlands are important habitats for birds. Yet, little is known of the relations between bird habitat and succession in these woodlands. We studied the bird community in cottonwood woodlands from early to late seral stages along the Missouri River in central South Dakota from 1990 to 1992 to describe quantitative relations between avifauna and ecological patterns of succession in cottonwood woodlands along the Missouri River. The vegetation in the early seral cottonwood was characterized by a high density of seedlings and saplings that were restricted to narrow bands along the rivers. Late seral cottonwoods were characterized by a few large old trees that extended across the flood plain. Seventy-nine percent of the bird species were woodland obligates. Birds that nest in trees or cavities were the most common, while shrub and ground nesting birds were relatively uncommon. Total bird abundance, species diversity, species richness, richness of woodland obligates, abundance in the tree-nesting guild, abundance in the cavity-nesting guild and abundance in the shrub-nesting guild were greater (P < 0.01) in late and late intermediate seral cottonwood stands. Patterns of bird use in cottonwood seral stages by individual species were less evident. Several species were more abundant (P < 0.08) in late or late intermediate seral cottonwood and no species were more abundant (P > 0.10) in early or early intermediate seral cottonwood. Bell's vireos (Vireo belli), indigo buntings (Passerina cyanea) and brown thrashers (Toxostoma rufum) occurred predominantly in early or early intermediate seral stages, but no significant differences among seral stages were noted. Expanses of late seral cottonwood on flood plains will likely decline because controlled river flows reduce flooding that is necessary for cottonwood regeneration. Cottonwood regeneration was evident only in narrow bands along the river channels. Cavity nesting species will be the most negatively affected by loss of late seral cottonwood.

We examined whether limber pine and skunkbush sumac individuals co-existing on the Pawnee Buttes of northeastern Colorado have the ability to access and utilize deep soil water resources. The δ¹⁸O signature of source water to the plants (deep soil water and precipitation) and plant cell water were measured in June 2000. The δ¹⁸O signatures of the two woody plant species were not significantly different from each other. However, the average δ¹⁸O signature of skunkbush sumac (−9.4‰) differed from the δ¹⁸O signature of deep soil water (−13.0‰), while the average δ¹⁸O signature of limber pine (−11.3‰) did not. Variability in the δ¹⁸O signature across plots and between individuals within a plot was relatively high for both species. These results suggest limber pine and some individuals of skunkbush sumac are able to access and utilize deep soil water resources at this site. This ability may confer an ecological advantage to these plants given the semi-arid climate of the site.

I investigated the effect of Coronilla varia invasion and subsequent reduction on the plant community and soil nitrogen availability in a degraded Illinois sand prairie. The presence of C. varia significantly increased soil nitrogen availability and significantly decreased native species richness and cover, but neither helped nor hindered a common non-native grass, Poa pratensis. One year after the drastic reduction of C. varia, soil nitrogen remained somewhat elevated and native species richness and cover low, but P. pratensis cover increased nearly six-fold. These results suggest that C. varia's impact might be continued through altered soil nitrogen. More important, however, was the strong response of P. pratensis, which could hinder restoration efforts by competing with native species.

To assess the usefulness of morphologic characters in identifying deer mice (Peromyscus maniculatus), white-footed mice (P. leucopus) and cotton mice (P. gossypinus) in sympatry, cranial and external measurements were recorded for two groups of these rodents. Each group contained individuals of the three species. One assemblage represented known individuals (species identifications verified using electrophoretic techniques) and the other unknowns (species identification not verified; test group). With the known group, we developed a system of identification based on selected morphologic features. These features were used to determine the identification of individuals in the test group. Following identification, individuals identified in the test group were confirmed using electrophoretic procedures. Two characters (greatest length of skull and length of hindfoot) separated 100% and 91% of P. gossypinus in the known group and 94.6% and 98% in the test group, respectively. A single external metric (tail length/total length) correctly classified 95% of P. maniculatus in both the known and test groups. A suite of four cranial (greatest length of skull, length of nasal, post-palatal length and length of diastema) and one external character (length of tail) correctly classified all of the individuals in the initial group and 90%, 91% and 100% of P. maniculatus, P. leucopus and P. gossypinus, respectively, in the test group. We concluded that morphologic characters can be used to accurately detect species of Peromyscus in sympatry.

Bats in forests have strict roosting habitat requirements. The current paradigm in bat conservation has been to identify the specific characteristics of individual roost trees that are selected by bats. Although this strategy is both practical and useful, it is also important to recognize landscape level interactions between bats and their roost habitats. Few studies have documented fidelity patterns of individual bats to specific roost habitat areas both within and between years. If bats are faithful to roost areas, conservation and management practices must incorporate the identification of the minimum size of areas required by bats during the summer season. We provide evidence that female eastern pipistrelles are faithful to small roost areas both within and between years, and that juvenile females exhibit female natal philopatry.