This study examined the temporal and landscape-scale patterns of root nitrogen concentration [N], root decomposition and N release from decomposing roots in oak-hickory forest ecosystems in southern Ohio. Sampling was conducted in three watershed-scale treatment units with different prescribed burning regimes, and each of these treatment units was divided into xeric, intermediate and mesic landscape positions. Root [N] decreased through the growing season in live roots but increased in dead roots. Root [N] was significantly lower in the xeric landscape positions, but only during the driest parts of the growing season. There was no consistent effect of prescribed burning on live or dead root [N]. Where differences among landscape position were detected, live root [N] was greatest in the most mesic landscape positions whereas dead root [N] was greatest in relatively xeric landscape positions. Overall, an average of 70% of original mass was lost from root litterbags and 80% of total N was released over one year of decomposition, with no significant differences among burning treatments in the instantaneous decay rate (k) or rate of N release. There were no differences among landscape positions in root decay rate or N release, even though prior studies have demonstrated strong landscape-position effects on leaf litter decomposition in similar sites. Overall, mass loss and N release from root litter is rapid in these ecosystems and relatively unaffected by either landscape position or fire frequency.

Fraxinus pennsylvanica woodlands are an important component of the Northern Great Plains ecosystem and critical habitat for many species of birds, mammals and plants. Many F. pennsylvanica woodlands are decadent, declining from closed-canopy to open-canopy stands with few tall shrubs and a ground layer dominated by Eurasian meadow grasses. Fire has been suggested to facilitate regeneration of these woodlands. Understanding the effects of fire on tree recruitment is essential if controlled burning is to be used for regenerating F. pennsylvanica woodlands. In 2001 I subjectively chose one stand with evidence of ground fire and a similar unburned stand at each of seven sites where F. pennsylvanica woodlands had experienced warm-season wildfire between 1988 and 1998. I measured density of F. pennsylvanica seedlings and number and size of crown sprouts for each tree in 3–4 sample plots in each stand.

 Fire had a significant negative effect on Fraxinus pennsylvanica regeneration at most sites. Trees in burned stands had three times as many crown sprouts (P = 0.02) that were nearly twice as large in diameter (P = 0.09) than in unburned stands. However, seedlings averaged 75% fewer in burn plots compared to unburned (P = 0.06). Burn plots with live mature F. pennsylvanica trees remaining had twice as many seedlings compared to those in which all mature trees were top-killed (P = 0.08). A large number of F. pennsylvanica trees were apparently killed by fire at several of the study sites. This study did not support using fire to restore F. pennsylvanica woodlands in eastern Montana.

The distribution of Bouteloua curtipendula in the eastern United States is generally limited to small and isolated populations on limestone-derived valley soils within the Ridge and Valley Physiographic Province in the Appalachian Mountains. In Pennsylvania, populations are <0.3 ha in extent and at least >16 km apart. Bouteloua curtipendula is found on extremely xeric sites: shallow, rocky, slightly alkaline, clay loams on south-southwest facing slopes. Diaspores of B. curtipendula can only travel at most a few meters on the wind and seeds are destroyed in the rumens of grazing ungulates; therefore, the long-distance dispersal mechanism is primarily by adhesion to animal fur. Two experiments tested the adhesion of B. curtipendula diaspores to eight mammal furs: coyote, red fox, rabbit, white-tailed deer, elk, bison, cattle and horse. A new index, the Dispersal Index (the product of “% diaspores that attached” and “% diaspores that remained after shaking”), was generated to represent the percentage of all diaspores that came into contact with the furs that remained attached. Bison and elk furs scored the highest on the Dispersal Index, suggesting that these two wild ungulates were important for B. curtipendula dispersal. However, both ungulates have been extirpated from most of their presettlement ranges in the Appalachians. According to herbarium records and modern field data, population numbers have declined by 48% during the past century, mostly due to agriculture, development and woody plant invasion due to fire suppression. Due to the absence of long-distance dispersers and the scattered distribution of suitable edaphic conditions, B. curtipendula is “trapped” on small sites that are shrinking due to woody plant invasion.

Goldenseal (Hydrastis canadensis L.) and American ginseng(Panax quinquefolius L.) have been harvested commercially for the past few centuries. Harvested populations can recover if vegetative propagules remain in the soil. Experiment I tested the efficacy of vegetative reproduction in goldenseal and ginseng. Partial and intact rhizomes and roots were planted in garden experiments in West Virginia and monitored for 1 y (goldenseal), and for 4 y (ginseng). During the experiment more than 40% of the propagule types of goldenseal (n = 5) and ginseng (n = 7) sprouted. Sprouting varied from year to year in ginseng, and dormancy and/or death occurred in both species. Of the ginseng propagules that sprouted, 77% were dormant for at least 1 y and half of those were not present in the final year of the experiment. Sprouting and reproductive status were dependent on propagule type for both species. In Experiment II we monitored recovery of wild populations of goldenseal and ginseng following natural and simulated harvests. After a harvest event leaving only 4 visible plants at the site, a goldenseal population recovered to 932 stems in the first growing season. In the subsequent 3 y, the population declined numerically, but the size of individuals increased significantly. In a harvested ginseng population, less than half the original number of ginseng plants were present 1 y after harvest. By the second year, stem number exceeded the preharvest count, but the demographic structure of the population had changed dramatically: 78% of the population was reproductive before harvest, while 0%, 4%, 7%, 18% and 26%, respectively, were reproductive in the 5 y following harvest. Both rhizomes and roots of goldenseal and ginseng are capable of regenerating plants, conferring a degree of short term resiliency following harvest.

We used an experiment and regression analyses to quantify effects of spatial variation in habitat structure abundance on a riverine macroinvertebrate community under winter conditions. Concrete slabs (0.21 m²; n = 24) with different numbers of stones (mean individual stone surface area = 6.44 cm²) attached to upper faces were placed in the James River and retrieved after 28 d. Macroinvertebrate abundance and taxonomic richness on slabs were significantly positively related to stone abundance. Total macroinvertebrate abundance and abundance of oligochaetes (Nais spp.), Asiatic clams (Corbicula fluminea), caddisflies (Leptoceridae), riffle beetles (Elmidae) and stoneflies (Strophopteryx sp.) were linearly related to stone abundance. However, nonlinear relationships occurred between stone abundance and macroinvertebrate taxonomic richness and between stone abundance and abundance of dragonflies (Erpetogomphus sp.), caddisflies (Hydropsychidae), chironomids (Eukiefferiella spp.), mayflies (Ephemerellidae) and stoneflies (Taeniopteryx sp.). Nonlinear relationships were usually characterized by dramatic increases in macroinvertebrate abundance and taxonomic richness across a gradient of increasing stone abundance when abundance was low (0–43 stones/0.08 m² slab face; 0–40% of slab face covered by stones), but weak responses to additional stones at higher stone abundance (84–160 stones/0.08 m²; 89–96% cover). These nonlinear relationships reflected similar nonlinear relationships between abundance of stones and particulate matter. We conclude that small quantities of habitat structure have significant positive effects on macroinvertebrate abundance and diversity in the James River during winter. At a local scale, habitat structure promotes macroinvertebrate colonization and retention by increasing habitat diversity. Stones and similar physical objects also indirectly benefit macroinvertebrates by trapping particulate matter that provides animals with food and additional habitat.

Senescence is the result of age-specific trade-offs among life history traits. Energetic trade-offs among various components of an organism's energy budget can also affect an individual's life span. An increase in reproductive effort, for instance, can result in less energy available for maintenance of body tissues resulting in a shorter life span. We investigated the effects of reproduction on longevity of giant waterbugs (Belostoma flumineum). Female giant waterbugs oviposit eggs onto the backs of males which then provide all post-copulatory parental care. The number of reproductions was manipulated in both males and females, and male waterbugs were divided into groups that provided parental care or did not. This allowed us to determine the relative costs of mating versus parental care. Both male and female waterbugs maintained as virgins outlived those that bred. Parental care incurred a greater cost in male waterbugs than the act of mating, but the number of reproductions had no effect on life span suggesting that a single reproductive event is as costly as many. In both males and females the age at first reproduction was significantly positively correlated with age at death.

Researchers and managers have suggested that a narrow range of ground-cover structure resulting from fire might be necessary for suitable Kirtland's warbler nesting conditions. Yet, Kirtland's warblers have bred successfully in numerous unburned stands and there is little direct evidence to indicate that ground cover structure is a limiting factor for nest sites or habitat suitability within appropriate landform-ecosystems. We documented the range of percent cover for dominant ground-cover structural components in burned and unburned habitat (stand ages 7–23 y) occupied by Kirtland's warblers. The mean percent cover for the dominant ground-cover structural components was lichen/moss (12.1%), blueberry (Vaccinium angustifolium) (9.5%), bare ground and litter (5.6%), sedge/grass (5.2%), deadwood (4.3%), sand cherry (Prunus pumila) (3.3%), sweet fern (Comptonia peregrina) (2.3%), coarse grass (1.8%) and bearberry (Arctostaphylos uva-ursai) (1.2%). Burned sites had significantly more deadwood, sweet fern and lichen/moss cover, while unburned sites had significantly more bare ground and sedge/grass.

We also investigated how fire, shade-history (i.e., pre-fire tree crown cover approximated by tree height and density) and succession influenced the percent cover of the dominant ground-cover structural components from 1 to 5-y after wildfire disturbance. The magnitude of differences in percent cover among shade-histories changed through time for the ground-cover components sand cherry, deadwood, grass/sedge and coarse grass. The percent cover of sweet fern, bearberry and bare ground was significantly different between some shade-histories. All dominant ground-cover components showed significant difference between at least one shade-history when compared to an unburned harvested reference stand. This suggests that more similarities exist among the three burned sites than between the burned sites and the unburned reference site. Our results suggest that fire, shade-history and succession influence ground-cover, but that various ground-cover components are affected differently by these factors. Because of the complex role disturbance history plays in maintaining ground-cover in Kirtland's warbler habitat, optimal management prescriptions are difficult to specify, especially when aspects of Kirtland's warbler ecology other than nest location are also considered. Although suitable ground cover structure can result without fire, maintaining prescribed fire is still desirable because this is a historically fire-regulated system. However, the range of ground-cover structures accepted by the Kirtland's Warbler and its resilience to disturbance suggests that suitable ground-cover for Kirtland's warbler could be maintained in some stands without burning after every timber harvest.

Experiments assessing rates of avian nest predation often find that nests near forest edges are at high risk of predation, suggesting the importance of forest fragmentation in recent population declines of ground-nesting passerines. However, the use of quail (Coturnix spp.) eggs in nest predation experiments may confound conclusions about edge effects because only large-mouthed predators are able to consume these relatively large eggs, but both large and small-mouthed predators consume smaller passerine eggs. We directly compared predation rates on artificial nests baited with quail eggs or with zebra finch (Poephila guttata) eggs; the latter are similar in size to the eggs of many neotropical passerines. In 1998 and 1999 we placed 392 artificial ground nests at edge and interior locations in two east-central Iowa forest fragments. Predation on these nests varied with egg type (quail or finch) and location (edge or interior) and there was a significant interaction between egg type and location: predation on quail eggs was greater at edges than in the interior, whereas finch egg predation was high in both edge and interior locations. Based on tooth imprints in clay eggs, we determined that large-mouthed predators were six times more active at edges, whereas activity of small-mouthed nest predators was evenly distributed between edge and interior locations. We suggest that the use of only quail eggs can exaggerate edge effects and that finch eggs or clay eggs used in conjunction with quail eggs in artificial nests can be used to estimate relative predation rates by large- and small-mouthed predators.

Since 1985 considerable expanses of highly erodible cropland have been enrolled in the Conservation Reserve Program (CRP). Areas enrolled in CRP provide wildlife habitat; however, habitat quality and specific resources on these sites vary in relation to seasonal biological processes of target wildlife species, planted cover and vegetation succession. Throughout the southeastern United States habitat quality for early successional species, such as northern bobwhite (Colinus virginianus), may decline as CRP grasslands age. Although disturbance may enhance and maintain habitat quality for bobwhite, concerns regarding perceived conflicts between wildlife habitat and soil erosion objectives of the CRP persist. During 1995 and 1996 we evaluated effects of strip-discing or prescribed burning on vegetation structure and composition and soil erosion in fescue (Festuca arundiacea) dominated CRP fields in Mississippi. Fall discing generally increased percentage bare ground and plant diversity and decreased percentage litter cover and litter depth. Fall discing enhanced bobwhite habitat quality, but responses diminished by the second growing season post treatment. Burning increased plant diversity and improved quality of habitat for bobwhite. Soil loss for all treatments was within United States Department of Agriculture tolerable limits. Discing or burning intensity on CRP fields could be increased without compromising soil erosion provisions of CRP.

The survival of obligate brood parasitic nestlings depends on their ability to exploit hosts' parental care, mostly at the expense of the unrelated nestmates. Foster parents are characteristically manipulated by parasitic young through more intensive begging displays. For example, young of parasitic brown-headed cowbirds (Molothrus ater) beg more loudly and elevate their head higher than the chicks of most host species. What is the developmental basis of this difference between parasite and its host species? Previous studies showed that intraspecific differences in some maternally deposited egg-yolk steroid hormone concentrations were related to differences in the begging behaviors and growth of hatchling birds. The prediction was tested that interspecific variation in yolk testosterone concentrations was related to consistent differences in the begging of hosts vs. parasites. Contrary to this prediction, yolk testosterone levels in the eggs of brown-headed cowbirds were not consistently higher than in host species: cowbird testosterone concentration was higher than in eastern phoebes (Sayornis phoebe), lower than in yellow warblers (Dendroica petechia), and similar to red-winged blackbirds (Agelaius phoeniceus). These results show that variation in egg-yolk testosterone concentrations alone is not related causally to differences in the begging behaviors between parasitic and host bird species. Nonetheless, it remains feasible that interspecific variation in both maternally deposited testosterone concentrations and embryonic hormone-receptor distribution together function to shape phenotypic differences in behavior and growth rate between avian hatchlings of different taxa.

Guilds consist of groups of species that use mutual resources or collections of overlapping resources. Guilds are often comprised of members of the same family or genus, but they can span larger taxonomic categories. Predacious arthropods, such as carabid beetles, centipedes and spiders, and small carnivorous vertebrates, such as woodland salamanders, overlap extensively in microhabitat and prey types. These taxa, though unrelated, may form important guilds of forest floor predators. We examined the behavioral interactions between a carabid ground beetle (Platynus tenuicollis) and a small woodland salamander (the red-backed salamander, Plethodon cinereus) in laboratory encounters. These species occur syntopically and feed on similar prey. Individuals of P. cinereus are territorial and defend cover objects against conspecific and congeneric intruders. Because both species require moist conditions, it seems probable that they would compete for resources, such as cover objects and prey, as the forest floor and leaf litter dries. We posed two general hypotheses: (1) salamanders will display territorial behavior toward intruding salamanders and beetles and (2) beetles will display territorial behavior toward intruding beetles and salamanders. Residents of each species were paired with control, intra- and interspecific intruders. In both species, residency status affected behavior—residents behaving more aggressively than intruders. Resident salamanders behaved similarly toward intruding salamanders and beetles, but no biting was observed. There were no significant differences in aggressive behavior of resident beetles among treatments. When physical attacks by beetles were observed, they were brief and often escalated to biting and chasing. Platynus tenuicollis bit intruders of both species in a significant number of trials; this often resulted in the production of adhesive secretions by P. cinereus that successfully immobilized P. tenuicollis. Antipredator behaviors observed in P. cinereus, and biting by P. tenuicollis of P. cinereus, suggest that intraguild predation may be as important as interspecific resource competition for these species of forest floor predators.

The Niangua darter Etheostoma nianguae is a threatened stream fish endemic to the Osage River basin of Missouri's Ozark uplands. We studied the darter's reproductive behavior under natural conditions in the wild to assist recovery efforts. In addition, techniques for captive propagation were developed in the event that wild populations should suffer precipitous declines. Seven spawning events were witnessed by snorkelers in swift riffle areas at mean (± SD) water depths of 23 ± 5 cm, column current velocities of 83 ± 12 cm/s and focal current velocities of 43 ± 9 cm/s. This combination of depth and velocity was used only for spawning; darters were found at slower velocities and greater depths when not spawning during spring and at slower velocities during summer. Niangua darters in captivity spawned in 38 liter aquaria with fine uniform substrate and no current velocity, and larvae were reared to the juvenile stage. Time from fertilization to hatching was 10–11 d at 16 C. Larvae swam up 3 d after hatching and remained in the water column 31–33 d before returning to the substrate. We suggest a spawning protocol that includes capturing wild males and females during April, isolating spawning pairs in 38 liter aquaria with fine substrate and maintaining low light levels during hatching. Young can be reared on brine shrimp nauplii, zooplankton and, later, frozen adult brine shrimp. A chronology of Niangua darter reproductive and early life history events is provided.

We live-trapped rodents in 2000–2001 at eight sites on a 3160 ha grassland and mesquite-oak savanna in southeastern Arizona that had been ungrazed since 1968, and on eight paired sites on adjacent cattle ranches. There were 917 captures of 14 species during 5760 trap-nights. Four species of Muridae (Sigmodon fulviventer, Baiomys taylori, Reithrodontomys megalotis and R. fulvescens) were significantly more common on ungrazed plots, while no species was more abundant on grazed plots. However, Heteromyidae as a group (especially Chaetodipus hispidus and Perognathus flavus) comprised a significantly higher proportion of total captures on grazed plots, and heteromyids as a percentage of total captures was positively correlated across all plots with amount of bare ground. One of the eight cross-fence sites also had been trapped in 1981–1983. In the 17 y between trapping events at this site: (1) the grass canopy on both grazed and ungrazed plots had become dominated by taller species, (2) a kangaroo rat (Dipodomys merriami) that had been the second most common species in grazed areas disappeared from both plots, (3) pocket mice increased on the grazed plot and declined on the ungrazed plot and (4) Muridae (excluding Peromyscus) as a percent of all captures increased by greater than 1.5-fold on both plots. Based on these results, and those from other field studies, we propose a model for the composition of rodent communities in grass/shrublands of the Southwest and Intermountain West, based on ground cover. Kangaroo rats (Dipodomys spp.) are abundant in areas with the most bare soil, Muridae (specifically, Sigmodon, Baiomys and Reithrodontomys) dominate areas with the most and tallest ground cover, and pocket mice (Chaetodipus and Perognathus) are common in areas of intermediate cover. In relatively mesic grasslands, livestock grazing and fire drive the rodent community toward one dominated by heteromyids instead of murids. In more arid landscapes, grazing and fire favor kangaroo rats over pocket mice.

Many factors influence bobcat (Lynx rufus) space use, movements and habitat selection, including prey distribution and density, season, breeding behaviors and intraspecific relationships. Knowledge of ranging behaviors and habitat selection is required to understand population dynamics and ecology of bobcats within temperate ecosystems. We radio-monitored 58 adult bobcats from 1989–1997 in central Mississippi. Males maintained larger home ranges and core areas than females, but sizes of these areas did not vary seasonally. Male bobcats moved at greater rates than females and bobcats moved at greatest rates during nocturnal periods. Movement rates were greatest during winter. Habitat selection at three spatial scales differed between genders and across seasons within gender. Our findings suggest that ≤8 y-old pine (Pinus spp.) habitats are important to bobcats, particularly females, as these habitats were selected by females at all spatial scales. However, our data also indicate that mature (>30 y) pine habitats are important to bobcats on our study area.

The eastern pipistrelle (Pipistrellus subflavus) is considered one of the most common and widely distributed species of bats in eastern North America, but little published information exists on its natural history. During surveys of numerous small caves in northwest Arkansas, we documented use by eastern pipistrelles and recorded ambient temperature readings in all caves and at roost and hibernation sites for individual bats. Using presence/absence data and a GIS system, we examined association of pipistrelle occurrence based upon landscape-level variables and cave structure. Hibernating eastern pipistrelles showed a significant preference for cave openings with east-facing aspects and significantly avoided caves on steep slopes during winter. These patterns appear to be due to the influence of cave ambient temperature. Significantly more eastern pipistrelles were found in caves with a wide range of temperature regimes within a season, but with little temperature variation between seasons. In our study site caves with east-facing aspects and on shallow slopes were significantly larger than those on the steep west-facing slopes. Larger caves have a greater buffer capacity from weather conditions, offering a wider range of temperature profiles within a season but varying little between seasons for consistent use by hibernating eastern pipistrelle bats.

We conducted a pot experiment examining the effects of simulated leaf herbivory and supplemental soil nutrients on extrafloral nectary (EFN) glands of Sapium sebiferum seedlings derived from native Chinese and invasive Texas seed stock. We predicted that simulated herbivory and increased soil nutrients would increase EFN activity. We also predicted that Chinese genotypes would have greater EFN activity than Texas genotypes. Simulated leaf herbivory significantly stimulated effluent production on EFN glands of seedlings from both genotypes, but there were no significant differences in EFN activity between genotypes or nutrient treatments.

I present preliminary data describing two new forms within the Cottus carolinae species-complex from the Ozark Highlands, the eyelash sculpin and the fringe-head sculpin. The eyelash and fringe-head sculpins can be diagnosed from all other species of Cottus by cirri (thin fleshy appendages), a character heretofore unknown in the genus. The eyelash sculpin can be further diagnosed by a few cirri above the eye and the fringe-head sculpin by a large number of cirri on the head and elsewhere. In addition, I provide data on pectoral fin ray number in the C. carolinae species-complex that validates the recognition of the Black River race in the Ozark Highlands (18–19 in Black River race, 13–17 in all other C. carolinae). The distribution of Ozark Highland members of the C. carolinae species-complex and a new size record are also discussed.

We compared the germination rates of running buffalo clover (Trifolium stoloniferum) seeds that had been passed through the digestive tract of a captive white-tailed deer (Odocoileus virginianus) with those that had not. We found no significant difference among germination rates of seeds passed through deer and those not, nor with seeds that were cold-stratified prior to planting and those that were not. Although white-tailed deer are viable vectors for running buffalo clover seed, our data suggest that the rates of ingested seed germination and survival are low. Dispersal and establishment of new populations by white-tailed deer herbivory may not contribute quickly or significantly to the recovery of running buffalo clover at present.