Registered users receive a variety of benefits including the ability to customize email alerts, create favorite journals list, and save searches.
Please note that a BioOne web account does not automatically grant access to full-text content. An institutional or society member subscription is required to view non-Open Access content.
Contact firstname.lastname@example.org with any questions.
Following logging and fire during 1890–1897 in an old-growth pine (primarily Pinus strobus and P. resinosa) stand near Found Lake in northeastern Wisconsin, the pattern and rate of forest succession was determined between 1950 and 1997. The original forest was reconstructed from analysis of stumps remaining in 1950. The study of stumps was a feasible retrospective approach to a detailed analysis of the variability and patchwork nature of the original (Before White Settlers, BWS) pine forests in northern Wisconsin. White birch (Betula papyrifera) and aspen (Populus spp.) dominated the Found Lake stand for about 80 y following logging and fire. Based on the Importance Value of trees and saplings, and basal area of trees, white pine (P. strobus) and especially red pine (P. resinosa) have begun to re-emerge as dominant species in the study area some 100 y after catastrophic disturbance. The abundance of sugar maple (Acer saccharum) trees has increased dramatically in recent years in the study area. Although variable, radial tree growth peaked consistently at 2–5 mm ring increment/y during the middle decades (1925–1960) of recovery for aspen, white birch, white pine and red oak (Quercus rubra borealis).
Balsam fir (Abies balsamea), sugar maple and white spruce (Picea glauca) are now (1997) predominant in the understory of the forest stand as saplings. This composition of the sapling layer suggests that in the absence of fire in the future the pines would eventually give way to balsam fir, sugar maple and white spruce.
I studied several factors that affected rates of seedling establishment for northern blazing star (Liatris scariosa var. novae-angliae) at Kennebunk, Maine. Fire stimulated blazing star fecundity in four ways: (1) There was a four-fold increase in the number of flowering plants in recently burned units (10.6%) compared to plants in units that had not been burned for 4 y (2.4%). (2) The number of seeds per flower head was greater in recently burned units. (3) Among flower heads that had been infested with predacious moth larvae, the percentage of depredated seeds (40–50%) was lower in recently burned units than in units that had not been burned for two or more years (78–93%). (4) Under natural conditions, seedling establishment was much greater in management units that had been burned 20 mo previously than in management units that had been burned either within the past 8 mo, or units that had not been burned for more than 4 y. These results suggest that northern blazing star benefits from fire and that these four factors are temporally linked. Fire reduced levels of seed predation and increased seed production, providing a large supply of viable seeds. Fire also reduced litter, thus providing a suitable substrate for seedling establishment and development.
Prescribed burning recycles essential plant nutrients and stimulates growth in prairie restoration. While reducing the content of nutrients in dry matter, prescribed burning may also alter the spatial variability and distribution of nutrients, which in turn could negatively impact long-term productivity. A study was conducted in a tallgrass prairie restoration at the Audubon Society's Goose Pond Sanctuary near Arlington, Wisconsin to characterize the content and spatial variability and distribution of macro- (i.e., N, C, P, K, Ca, Mg and S) and micro-nutrients (i.e., Zn, B, Mn, Cu, Fe, Al and Na) in the aboveground litter before burning and in the ash after burning following 3- and 6-y burn intervals. Aboveground litter mass was significantly higher in 2001 after the 3-y burn interval than in 1998 after the 6-y burn interval. The amount of preburn litter was consistently reduced by >90% for both burn intervals, but the reduction of dry matter and the reductions in mass of N, C, P, K and S were significantly higher in 2001 than in 1998. The 6-y burn interval resulted in nutrient export that was similar to nutrient inputs from atmospheric wet deposition, whereas the 3-y burn interval resulted in the export of N, K, Ca and Mg faster than they were replenished. Prescribed burning significantly affected the spatial variability of dry matter and the concentration and content of most macro- and micronutrients. However, prescribed burning had little effect on the pre- and postburn spatial distributions of macro- and micro-nutrient masses, which were similar to pre- and postburn spatial distributions of litter and ash masses, except for Fe and Al which had atypically large concentration variances.
The Chinese tallow tree (Sapium sebiferum) was introduced into the southeastern United States in late 1800s and has rapidly naturalized throughout the region's coastal ecosystems. Because tallow forms monotypic woodlands, we hypothesized that allelopathic interference is a mechanism by which tallow maintains and expands its presence. Laboratory experiments were performed using black willow (Salix nigra), baldcypress (Taxodium distichum) and tallow, as test species, to examine the hypothesis that aqueous tallow extracts inhibit seed germination and seedling root growth, shoot growth and mass. Extracts were prepared from tallow litter, woodland soil from under tallow trees and fresh tallow leaves. Samples were collected during October, January, April and July to determine any seasonal differences in allelopathic potential. Germination, root and shoot lengths and seedling mass differed (P < 0.05) among treatments for willow, baldcypress and tallow. Black willow germination did not vary (P > 0.05) among control and April litter or April soil treatments; the treatments designed to mimic conditions when black willow naturally germinates. Although germination was lower (P < 0.05) in April fresh leaf and July litter, soil and leaf treatments than control treatments, black willow does not germinate during July nor do black willow seeds contact fresh tallow leaves during April. Germination rates for baldcypress and tallow during April and July litter and soil treatments were higher (P < 0.05) than control treatments. Similarly, baldcypress seedling root length, shoot length and mass were the same or higher than control treatments (P < 0.05). Tallow seedling root length, shoot length and mass were lower (P < 0.05) in controls versus April and July litter and soil treatments. Our experiment questions the validity of allelopathic interference as a mechanism enhancing tallow invasion or maintaining woodlands once established. Because of its enhanced germination and seedling growth when exposed to its own experimental treatments, tallow may in fact be perpetuating its own woodland(s) by self facilitation, rather than inhibiting other plant survival by allelopathic interference.
The nonindigenous invasive, Lonicera japonica, is a woody vine with a well-documented capacity for vegetative spread. In contrast, few data exist on its potential for establishment by seed. Lonicera japonica is biotically pollinated and xenogamous, requiring pollen from a genetically distinct individual for fruit set. We conducted hand-pollinations to determine if the fruit set of L. japonica in Arkansas was pollinator limited. Naturally pollinated control shoots produced fruit from 17.4% of their flowers, but the hand-pollinated flowers had a fruit set of 78.7%. Shoots with pollinators excluded set fruit on only 2.1% of the flowers. To determine geographic patterns in fruit set we surveyed seven different sites along the western edge of the naturalized range of L. japonica. Average fruit set on primary shoots was 13 ± 4.1% (mean ± se), whereas the secondary shoots averaged 23 ± 6.7%. These results support our conclusion that sexual reproduction in populations of L. japonica along the western edge of its naturalized range is limited by a lack of pollination.
The 25 nominal species of the menoponid genus Machaerilaemus have been studied, with 10 determined to be valid and 13 to be new junior synonyms and two assigned to another genus. Descriptions are given for the previously described species and for five new species: M. cyanocittae (type host Cyanocitta cristata), M. diglossae (type host Diglossa baritula), M. laticapitus (type host Leptasthenura aegithaloides), M. tangarae (type host Tangara larvata) and M. hirsutus (type host “Honeycreeper”). A key is provided for identification of the 15 species now recognized in the genus.
The ecology and life histories of odonates were studied in a headwater, sand-bottomed coastal plain stream in Virginia. Quantitative sampling of odonates in sand and silt sediments, on submerged snags and in debris dams was conducted monthly for 13 mo. Six species of odonates were common in the stream. Calopteryx maculata (Calopterygidae) had a univoltine life history, whereas Boyeria vinosa (Aeshnidae) Cordulegaster maculata (Cordulegastridae), Gomphus cavillaris, Hagenius brevistylus and Progomphus obscurus (Gomphidae) were semivoltine. The odonates were most abundant in debris dams, less abundant in silt and sand sediments and least abundant on snags. Habitat-specific production of odonates was 1.3 g m−2 y−1 in debris dams and 0.1 − 0.3 g m−2 y−1 in the sand, silt and snag habitats. The production to biomass ratio (P/B) for Calopteryx was 5.9, whereas ratios for semivoltine species ranged from 2.0 − 4.0.
Analysis of overlap in the use of habitat, food and time showed that greatest ecological separation of the species was in their different use of habitat. Boyeria vinosa and Calopteryx maculata primarily inhabited debris dams, Hagenius brevistylus and Gomphus cavillaris were most abundant in silt and Progomphus obscurus was found almost exclusively in sand. Cordulegaster maculata occurred throughout the stream except on snags. Narrow niche breadths for B. vinosa, C. maculata and P. obscurus based on their use of habitat suggest high fidelity of these species to one habitat, whereas Cordulegaster maculata, with the broadest habitat niche breadth, was a habitat generalist. There was little difference among the species in prey items. Trophic niche breadths of all species were broad, all species feeding on a wide variety of invertebrates, in particular Chironomidae, Ephemeroptera and Plecoptera. Little ecological separation of the species occurred based on their use of time, all species occurring in the stream throughout the year with little staggering of life history events or growth patterns. Seasonal patterns of changing resource availability and the dynamic nature of the stream environment likely are important in regulating the distribution, abundance and interactions of the odonate community in this stream.
In tallgrass prairie, cicadas emerge annually, are abundant and their emergence can be an important flux of energy and nutrients. However, factors influencing the distribution and abundance of these cicadas are virtually unknown. We examined cicada emergence in plots from a long-term (13 y) experimental manipulation involving common tallgrass prairie management practices. The plots were arranged in a factorial experimental design, incorporating annual burning, mowing and fertilization (10 g N m−2 and 1 g P m−2). One cicada species, Cicadetta calliope, responded positively to fire, but negatively to mowing, and was most abundant in plots that were burned, unmowed and fertilized. Increased density of C. calliope in this treatment combination is related, in part, to increased availability of oviposition sites aboveground. Furthermore, C. calliope females from fertilized plots were significantly larger in body size relative to females from unfertilized prairie. Another cicada species, Tibicen aurifera, emerged only from unburned plots. The mechanism underlying this negative response to fire is unclear, but may be related to the presence of standing dead vegetation or improved quality (i.e., N content) of belowground plant tissue in unburned plots. In contrast to C. calliope, the density of T. aurifera was not affected by mowing or fertilization. However, like C. calliope, the body size of T. aurifera females was significantly greater in fertilized plots. Cicada emergence resulted in N flux ranging from 0.05–0.16 g N m−2 in unburned plots, but N flux (as cicada biomass) from annually burned plots was negligible.
During a 2 y study (February 1993–January 1995) I searched a total of 519.4 km of canal and levee banks in 304.4 h to study Florida kingsnake (Lampropeltis getula floridana) activity. I gathered and compared data on seasonal activity patterns of two populations in southern peninsular Florida, around Lake Okeechobee and southern Dade County. Snakes from both populations exhibited two activity peaks, one in spring and one in fall. The highest frequency of encounters was in March and April during the peak of the breeding season. During this time males were encountered more often than females, possibly because they are actively searching for mates. Encounter rates are constrained by temperature rather than precipitation. The majority of snakes were found in the open aboveground between 24 C to 29 C, with the highest frequency at 27 C. At lower and higher temperatures encounter rates decreased as snakes may retreat into refugia. Adults were encountered more often than juveniles. Adults are primarily diurnal, whereas juveniles exhibit crepuscular and nocturnal behaviors. An apparent ontogenetic shift in diel activity occurred at approximately 90 cm SVL, where secretive juveniles gradually become more diurnal.
Crocodilians are able to consume larger meals than most vertebrates. The varied diet of many crocodilians makes them excellent models to study the effects of meal size and temperature on gastric retention time. Consumption of turtles by American alligators, Alligator mississippiensis, is expected to be overemphasized because of prolonged stomach retention of epidermal scutes. We conducted experiments to identify exogenous factors that control gastric retention time of turtle scutes. Stomach contents of nine juvenile alligators, fed various percentages of their body mass, were used to compare retention intervals of turtle scutes. As meal size increased, the stomach retention interval increased. The retention interval of scutes was not affected by ambient temperatures over the range of 30–35 C.
Orangethroat darters Etheostoma spectabile occupying thermally contrasting streams within the same watershed were tested for differences in thermal responses by comparing their critical thermal maxima (CTM) and short-term growth. Individuals from a spring branch population had a lower CTM, better growth at low temperatures and more inhibited growth at higher temperatures compared to individuals collected from a thermally variable adjoining stream reach. The findings support the contention that intraspecific differences in thermal tolerance and growth may exist at relatively localized scales within a small watershed.
The yellowcheek darter, Etheostoma moorei (Raney and Suttkus), is an endemic species of the upper Little Red River, Arkansas. Population estimates over the past two decades have identified an 80% reduction in numbers. Seventeen presumptive loci and six meristic characters were analyzed for 85 individuals to determine the relatedness of populations from three headwater streams. Genetic distances, based on allozyme analysis ranged from 0.000 to 0.213, with each stream population partitioning into distinct subpopulations. Turkey Fork individuals had high genetic distance values from Middle and South Fork individuals. None of the six meristic features studied demonstrated significant differences between stream sites. These findings and previous ecological and life history studies all suggest that the Turkey Fork and Middle/South Fork populations be treated as unique management units.
Few published studies detail the biology and natural history of the madtoms (Noturus spp.), and information about their habitat requirements is even more scarce. We described diurnal habitat use for N. exilis, N. albater and N. flavater in Jacks Fork River and N. exilis and N. flavus in Big Piney River, Missouri. Madtoms were captured incidentally with a 1-m2 quadrat sampler while conducting quantitative crayfish sampling from June–September 1995–2000. Sampling was stratified among five macrohabitats, and microhabitat measurements were recorded with each sample. A total of 2206 samples yielded 476 madtoms. Noturus exilis was most common in both rivers, occupied all macrohabitats and used a wide range of depths and current velocities. During late summer it increased use of backwater pools and emergent vegetation patches. Noturus albater was largely rheophilic and used shallow depths (0.06–0.57 m) and high current velocities (0.00–0.60 m/s). Noturus flavater was uncommon and associated with deep water (0.14–2.45 m). Noturus flavus was also largely rheophilic and associated with fairly shallow depths (0.03–0.46 m) and high current velocities (0.00–0.68 m/s). There were few apparent differences among madtoms with regard to associated substrate composition.
Few studies have been conducted on the food habits of the ocelot (Leopardus pardalis), considered an endangered feline in Mexico. Past studies showed that rodents were the main component of ocelot diet. In our study ocelot prey consumption was measured as frequency of occurrence of prey in scats and then converted to biomass. The spiny-tailed iguana (Ctenosaura pectinata) was the most important prey of ocelots, followed by the spiny pocket mouse (Liomys pictus). Other rodents and some birds were also present in the scats, although representing only a minor proportion of the ocelot's diet. Evidence of subadult white-tailed deer (Odocoileus virginianus) was also found in scats indicating that ocelots can either capture prey bigger than themselves or are using deer as carrion.
I studied the natural history of the Allegheny woodrat (Neotoma magister) in Virginia. The species is considered endangered, threatened or of special concern by Natural Heritage Programs in every state in its range. Important details of the woodrat's life history, specifically reproduction, growth rate and juvenile survival, are unclear. I trapped 163 juveniles and subadults 416 times over 10,107 trap nights (TN) during an 11-y study. Forty seven percent of juveniles were caught in May and June, whereas 48% of subadults were caught in September or October. Neither juveniles (P < 0.01) nor subadults (P < 0.01) were caught in proportion to trap effort in each month. Based on six litters of 14 juveniles, the average litter size was 2.3 pups. Based on captures and observations, I concluded that woodrat reproduction occurs throughout the year. The average daily weight gain (±se) for a woodrat first caught as a juvenile was 1.26 g/d (±0.23g/d). The average daily weight gain (±se) for a woodrat first caught as subadult was 0.94 g/d (±0.21g/d). Fifty-five percent of all juveniles were never caught after their initial capture. Year to year recapture rate for juveniles was 19%. Twenty-three of 39 (59%) juvenile males were caught only once or on consecutive days in a trap session and never caught again. Sixteen of 31 (48%) juvenile females were caught only once or on consecutive days in a trap session and never caught again.
We determined production and survival of elk (Cervus elaphus nelsoni) calves in Michigan using a variety of methods to index herd productivity. Calf production in Michigan was comparable with the highest rates ever recorded for North American elk. Calf survival averaged 0.90 (sd = 0.05), 0.97 (sd = 0.04) and 0.87 (sd = 0.05) for summer, winter and annually, 1987–1991. Calf survival rates in Michigan were higher than in other North American elk populations. Continued high calf production, in combination with high calf survival, indicates that elk condition is excellent in Michigan, as habitat quality allows cow elk to breed and successfully raise a calf, essentially every year, despite the high energetic demands associated with late gestation and lactation.
Snails in the family Pleuroceridae have strong effects on community structure and energy and nutrient pathways in many North American rivers and streams. Identifying factors determining densities and biomass of pleurocerids is, therefore, an important step toward predicting the relative importance of these snails in an ecosystem. We used plot sampling to identify environmental factors causing variation in demographic features of the pleurocerid snail Leptoxis carinata in a 3rd order stream in south central Virginia. Snails were collected from forty 0.22 m2 plots located within a 165 m segment of Fishpond Creek and L. carinata density, mean shell width, mean body mass and total biomass in each plot were measured. Measurements were also taken for several environmental variables. Multiple regression indicated that topographic complexity of substratum was the primary cause of variation in L. carinata density and total biomass among plots. Snail density and total biomass were both greater in topographically complex plots with large substratum particles (i.e., boulders, cobble) that likely provide refuge from high flow events and are preferred habitat for foraging. Temporal changes in several demographic features were also quantified. Mean shell width and body mass of individual snails increased during the 28 d study (12 March 2001–8 April 2001), but total biomass declined following a flood that occurred from 25 March 2001–5 April 2001.
In August and September of 1991 we observed three groups of neonatal prairie rattlesnakes (Crotalus viridis viridis) near a prairie dog town in the Sand Hills (Cherry County, Nebraska). One of these groups included at least 31 neonates and 2 postpartum females. In addition to spatio-temporal association of neonates and putative mothers, we observed a radio-tagged male prairie rattlesnake consecutively visit two natal sites, just before and just after parturition. Mean mass of neonates in two groups was below the range previously reported for this subspecies. Young-of-the-year (YOY) captured during ingress were longer and weighed more than neonates captured at birth. Feces collected from nine YOY captured at hibernacula contained pocket mouse (Perognathus spp.) remains. In contrast to other intensively studied populations, most YOY in the Sand Hills appear to feed and grow before first hibernation.
We studied the sex ratio of a population of common musk turtles (Sternotherus odoratus) from Dewart Lake in north-central Indiana. From 1979 to 2000 we trapped S. odoratus nearly annually using wire traps or fyke nets. Sex ratios were consistently male biased (average = 64.9% males) and did not vary between trap types or time of day. Available evidence points to differential mortality of the sexes as a possible cause for the biased sex ratios. However, additional work is needed.
The seed coat of Stylisma pickeringii (Torr.) Gray var. pattersoni (Patterson bindweed), an endangered species of Illinois sand prairies, inhibits water uptake and seed germination. The purpose of this research was to find an effective and efficient way to scarify seeds of S. pickeringii to aid reintroduction into its natural habitat. Seeds were collected from sandy areas close to the Illinois River near Snicarte (Mason Co.), Illinois during the summers of 1998 and 1999. Experiments were conducted to determine the best scarification techniques (basal cut, sandpaper shakes, sulfuric acid, sand shakes and sonication). Initially, each technique was evaluated by scarifying the seeds for different times (except for the basal cut). The optimal time for each scarification technique then was compared. Scarified seeds were germinated in petri dishes at 25 C, 16 h photoperiod, with a mean light intensity of 51 μ mol m−2s−1. The basal cut, 48 h sandpaper shake, 120 min acid soak and 72 h sand shake techniques did not differ significantly in germination (96, 92, 84 and 84%, respectively). The sonicator technique and the unscarified control yielded only 4 and 0% germination, respectively. For scarification of S. pickeringii seeds the 48 h sandpaper shake and 120 min acid soak were very effective and efficient relative to other techniques. Of these two techniques, the sandpaper shake is safer than the acid soak, although when scarifying large numbers of seed, the sandpaper shake would require a large shaker. The techniques have potential applicability to other threatened and endangered species whose seed coat also inhibits germination.
The Ozark big-eared bat (Corynorhinus townsendii ingens) is an endangered subspecies currently known only from small populations in Arkansas and Oklahoma. Between October 1998 and May 2000 we surveyed 93 small caves in northwestern Arkansas six times. During these surveys we encountered Ozark big-eared bats in 8–10 caves every season. During surveys in spring, summer and autumn, we encountered mainly lone individuals, while up to seven individuals were encountered together during winter surveys. Winter encounters were mainly in limestone caves, particularly those with vertical or near vertical sinkhole entrances, whereas caves with more varied characteristics were used in other seasons. Temperature may also have been a factor in choice of caves, with colder caves being preferred, especially in winter. Our data indicate that Ozark big-eared bats use many small caves in the study area. These caves should be protected, and other groups of small caves in the Ozarks should be surveyed for Ozark big-eared bats.
Oberholser's resurrection of Bubo virginianus occidentalis Stone (considered by Stone himself as a synonym of B. v. subarcticus) has confused the understanding of the distribution of midcontinental populations of the great horned owl. With the clarification of the taxonomy, B. v. subarcticus proved to be the nesting populations in the prairie-parklands of Wyoming, Montana and North Dakota. Introgression with adjacent subspecies occurs at least in western Montana and in South Dakota.