Insect-induced galls are observed on plants throughout the world, but patterns of gall-inducing insect species richness are not random. In the USA and Brazil, species richness increases with decreasing altitude, which is associated with increasing temperature and aridity. At a given elevation the number of gall-inducing insect species is also higher in drier habitats than mesic habitats. However, variations in the number of potential host plant species, related to soil fertility, may be the cause of these patterns, not differences in temperature and aridity.

We examined patterns of species richness of gall-inducing insects by counting the number of gall-inducing insect species and plant species, and measuring soil phosphorus, in replicate dry and mesic plots at five locations along an altitudinal aridity gradient in Big Bend National Park, Texas. Almost all galls were on woody plant species (trees or shrubs). We found the greatest number of gall-inducing insect species at intermediate elevations, and in more mesic habitats, rather than at low altitudes or in drier habitats. The number of woody plant species was also highest at intermediate elevations and in mesic habitats. Soil phosphorus was high at both extremes of the altitudinal gradient, where few gall-inducing insect species occurred.

Our results show that patterns of species richness of gall-inducing insects may largely be a function of the number of woody plant species present. The chance of a gall-inducing insect finding its specific host plant species increases as the number of woody plant species increases. The effect of soil fertility requires further study but the findings suggest that high soil fertility does not favor gall-inducing insects.

The food web of Symmorphus cristatus wasps, leaf beetle larvae (Coleoptera: Chrysomelidae) and willow (Salix spp.) trees is a model system for studying the chemical ecology of plant, herbivore and predator interactions. However, little is known about the natural history and prey use of the predatory wasps. We conducted detailed observations of nesting behavior and quantified time allocation to nest building activities in Big Pine Creek in the eastern Sierra of California. Symmorphus cristatus exhibits aggressive territorial behavior over nesting and mating sites, but does not respond aggressively to kleptoparasitism by cuckoo wasps Chrysis nitidula. We also compared prey use, nest provisioning and nest architecture of wasps at Big Pine Creek and at Sebastopol, near the central California coast. Using trap-nests we identified two new prey species for S. cristatus at Sebastopol: Plagiodera californica and Chrysomela schaefferi (Coleoptera: Chrysomelidae). There were significant differences in nest architecture for the two allopatric wasp populations and, although they do not use the same prey species, populations did not differ in the mean mass of prey provided for each offspring. Five other cavity-dwelling insect species pre-empted nest sites in Sebastopol. Prey species in Sebastopol differ in the chemistry of their larval secretion. The main component of C. schaefferi secretion is salicylaldehyde, which is derived from the willow host plants. Plagiodera californica secretion contains (epi)plagiolactone, an autogenously produced monoterpene-based defensive secretion. This is the first evidence that S. cristatus uses prey larvae that possess a monoterpene-based secretion.

Eastern wild turkeys (Meleagris gallopavo silvestris) in the Ouachita Highland Province of westcentral Arkansas have some of the largest reported home ranges for this subspecies. Previous research on wild turkeys has generally attributed large home-range size to forage abundance or quality. However, limitations in reproduction by wild turkeys in the Ouachitas may influence home-range size and habitat selection. To discern factors governing home-range size, I examined habitat use by 54 female wild turkeys from 1993 to 1996. Shortleaf pine (Pinus echinata) and mixed pine–hardwood sawtimber were selected over other overstory cover types, whereas blackgum (Nyssa sylvatica), red maple (Acer rubrum) and white oak (Quercus alba) were favored in the understory. Mean fixed kernel home-range size during the breeding season was 18.9 km², the largest reproductive period home range reported for the eastern subspecies. Home-range size varied as a function of age, body mass, reproductive status and the structure of selected habitats. Subadult females occupied larger home ranges (x̄ = 32.0 km², se = 7.0) than adult females (16.3 ± 1.7 km²) and moved greater distances between nest sites in subsequent years (8.9 ± 1.8 km vs. 2.4 ± 1.1 km, respectively). After removing effects of age, heavier females occupied smaller home ranges than lighter females. Nesting individuals occupied less area than non-nesters, and female turkeys that occupied smaller areas avoided stands of seedlings and saplings in favor of mature poletimber. Taken together, effects of physiological condition and experience influenced home-range size in female wild turkeys in westcentral Arkansas.

Home ranges of lesser prairie-chickens (Tympanuchus pallidicinctus) include up to several thousand ha of several habitat types that are concentrated around leks (traditional display grounds). A geographic information system (GIS) was used to relate changes in vegetation and land use to population trends of lesser prairie-chickens in Oklahoma, Texas and New Mexico. We quantified changes in vegetation within 4.8 km of lesser prairie-chicken leks and examined relationships among those changes and long-term population trends based on the number of displaying males per lek. Five of 13 populations declined between 1959 and 1996. Landscapes in which populations of lesser prairie-chickens declined were characterized by greater rates of landscape change and greater loss of shrubland cover types than landscapes in which populations did not decline. Changes of specific cover types were not as important as the total amount of change occurring on landscapes. Conservation of lesser prairie-chickens should focus on stability of vegetation and land use and specifically attempt to maintain continuity of shrublands within 4.8 km of existing leks.

Bird use of terraces in rowcrop fields was evaluated during 1996–1997 in southwestern Iowa by line transect counts of birds, nest searches and nest monitoring. Twenty-six bird species were observed in terraces. Red-winged blackbirds (Agelaius phoeniceus) and dickcissels (Spiza americana) were most abundant, accounting for 58% of the total bird abundance. Bird abundance in terraces (x̄ = 463.0 birds/100 ha, se = 33.0) was less than that in other strip-cover habitats such as grassed waterways and roadsides, but greater than that in rowcrops. Five species nested in terraces. We found 64.8 nests/10 ha of which 76% were red-winged blackbird nests. Predation resulted in failure of 73% of all nests. The relative contribution of terraces to grassland bird conservation is minor, and changes in current terrace management practices would not likely improve conditions for birds nor be economical.

Henslow's sparrow (Ammodramus henslowii) abundance, measured as average number of males at point counts, varied within and among reclaimed mine grasslands of southwestern Indiana. The 19 mine grasslands studied range from about 100 to 3200 ha and vary in landscape structure and composition both within the mines and in relation to the surrounding area. Nevertheless, few landscape-level attributes of mine grasslands were related to Henslow's sparrow abundance. Landscape composition (e.g., percent forest or grassland cover), in particular, had a negligible effect on Henslow's sparrow abundance. Neither habitat patch size nor shape had a significant effect on Henslow's sparrow abundance, but these birds tended to avoid habitat edges. Variation in Henslow's sparrow abundance was, however, influenced by the composition and structure of local vegetation. The relative “landscape insensitivity” of Henslow's sparrows probably reflects the large area of mine grasslands rather than a true lack of landscape-sensitivity in this species.

Widespread establishment of seedling aspen (Populus tremuloides) occurred in Yellowstone National Park (YNP) following the extensive1988 fires. Aspen stands occupy ∼2% of YNP and aspen stems are intensively browsed by native ungulates. Chemical composition, especially secondary compounds, may influence levels of herbivory and, hence, survival of aspen, but concentrations of such compounds in aspen in the northern Rocky Mountains are not known. Quantitative profiles of foliar nitrogen and secondary compounds (condensed tannins and the phenolic glycosides, salicortin and tremulacin) in aspen were assessed to address the following questions: (1) Do concentrations of secondary compounds differ between seedling and mature aspen stands? (2) Do concentrations of secondary compounds in seedling aspen differ between unbrowsed and artificially browsed seedlings? (3) Among mature aspen stands, do concentrations of secondary plant compounds differ among, (a) burned and browsed, (b) unburned and browsed and (c) unburned and unbrowsed stands? Concentrations of phenolic glycosides were significantly higher in seedlings than in mature stands, although condensed tannin concentrations and leaf nitrogen were higher in mature stands. Concentrations of leaf nitrogen and all secondary compounds were greater in unbrowsed seedlings than in seedlings subjected to simulated browsing. Concentrations of secondary compounds did not differ between mature aspen stands that were unburned regardless of whether they were browsed; however, burned stands (all of which were browsed) had significantly greater concentrations of secondary compounds and leaf nitrogen than the unburned stands. Results from this research suggest that foliar phenolic glycosides and tannins are not active defenses induced in response to browsing by large mammals. Rather, variation in levels between juvenile and mature ramets represents ontogenetic shifts in expression of defense, whereas variation between clipped and unclipped seedlings results from shifts in carbon/nutrient availability.

Loss of plant species diversity in wetlands has been linked to high nutrient conditions. In particular, Typha spp. are known to form monotypic stands in fertile wetland systems. In this study marsh mesocosms were used to study the effect of nitrogen (N), phosphorus (P) and nitrogen and phosphorus (N and P) additions on density, biomass and nutrient dynamics of Typha latifolia L. and the sedge Schoenoplectus tabernaemontani (C.C. Gmel) Palla (a.k.a. Scirpus validus Vahl.) grown in size- and density-symmetric and in size- and density-asymmetric mixtures. Dynamics of Typha and Schoenoplectus mixtures were also estimated along a nutrient gradient in a created wetland. Typha responded with increased growth to higher nutrient conditions more than Schoenoplectus in the first year, but Schoenoplectus responded more than Typha in the second year when nutrient additions were stopped. Typha grew better compared to the control with the addition of nitrogen and phosphorus in both the asymmetric and symmetric mixtures. Nitrogen or phosphorus, when added alone, did not increase the growth of Typha when it was grown with Schoenoplectus. The presence of a one-year-old stand of Schoenoplectus reduced aboveground growth of introduced Typha in both high- and low-nutrient conditions. In a created marsh Typha biomass decreased and Schoenoplectus biomass increased along a gradient of decreasing nutrient concentrations. N:P ratios in aboveground tissues of both plant species were less than 14:1 (by weight) suggesting N limitation. Plant tissue ratios, however, were close to the Redfield ratio of 7.2:1, suggesting no nutrient limitation.

Subcanopy shrubs and perennial herbs inhibit recruitment of canopy trees in forests around the world. Although this phenomenon is widespread, and can have significant effects on community dynamics, the mechanisms of inhibition are not well understood. In the southern Appalachian region, Rhododendron maximum inhibits the recruitment of canopy trees in forests of northern red oak (Quercus rubra). We have shown, in previous research, that processes occurring before canopy tree seed germination are not responsible for this inhibition. Therefore, post-germination processes, such as competition for resources are most important. In this study we show that the presence of a thicket of R. maximum in the understory reduced the availability of light by 80%, the frequency and duration of sunflecks by 96%, the availability of water by 20% and the availability of several soil nutrients (particularly cations) by variable amounts. Moreover, the survival of Q. rubra seedlings in the understory over 3 y was significantly reduced (by about 40%) in the presence of a R. maximum thicket compared with forest without a thicket. Seedling survival was positively associated with light availability, but the slope and intercept of that relationship was different in forest with or without R. maximum. Therefore, belowground processes are involved in reduced seedling survival under the R. maximum thicket. The resources most associated with survival of Q. rubra seedlings were water and light. Although many soil nutrients were significantly lower in forest with R. maximum than in forest without R. maximum, no individual nutrient was a significant covariate with Q. rubra survivorship. Our data indicate that competition for resources both above- and belowground is an important mechanism for inhibition of canopy tree recruitment by R. maximum. Light is important to seedling survival, but is not the only important factor. Water availability and the ability to accumulate soil nutrients are equally or more important than light to survival of canopy tree seedlings in the presence of a subcanopy thicket of R. maximum.

Our objective was to evaluate the effects of soil disturbances created by the plains pocket gopher (Geomys bursarius) on the structure of a tallgrass-prairie plant community. We predicted that soil mounds and burrows would provide sites for the establishment of subordinate plant species, thereby increasing regional plant community richness in this ecosystem that is highly dominated by perennial C₄ tallgrasses. Our results, however, revealed that plant species richness and biomass were temporarily decreased or unaffected in areas disturbed by gophers. Moreover, the species found locally on mounds and burrows were a subset of the dominant plants present in the undisturbed plant community and graminoids were more frequent on disturbances than forbs. Our results indicate that perennial graminoids predominate in the rapid recovery of vegetation on pocket gopher mounds and burrows. This preempts the establishment of less frequent forbs and, contrary to our predictions, decreases plant community richness.

We conducted a study to test the hypothesis that there is no difference in the frequency with which southern short-tailed shrews, Blarina carolinensis, use mole tunnels during cold weather vs. during warm weather. Snap-trapping was conducted for eighteen consecutive nights at each of eight different grids, four during winter and four during late spring. The proportion of aboveground captures during winter trapping was significantly less than during spring trapping, indicating that individuals of B. carolinensis use mole tunnels more frequently during cold weather. However, during both winter and spring, significantly more captures of shrews occurred in mole tunnels than aboveground. During both winter and spring sampling, subterranean temperatures varied less than those at the soil surface. Mean body weight of males captured during winter was significantly greater than that of males captured during spring and of females captured during both winter and spring.

Quarrying in east-central Indiana has uncovered richly fossiliferous unconsolidated sediment buried beneath Pleistocene glacial till. The fossiliferous layer is part of a sedimentary deposit that accumulated in a sinkhole developed in the limestone flank beds of a Paleozoic reef. Plant and animal (mostly vertebrate) remains are abundant in the fossil assemblage. Plants are represented by a diversity of terrestrial and wetland forms, all of extant species. The vertebrate assemblage (here designated the Pipe Creek Sinkhole local fauna) is dominated by frogs and pond turtles, but fishes, birds, snakes and small and large mammals are also present; both extinct and extant taxa are represented. The mammalian assemblage indicates an early Pliocene age (latest Hemphillian or earliest Blancan North American Land Mammal Age). This is the first Tertiary continental biota discovered in the interior of the eastern half of North America.

Sequences of alternate, second nearest neighbors, in rows and columns, effect an exhaustive decomposition of an initial lattice into four smaller lattices with no points in common. The expected second neighbor joins count, and the second neighbor variance, for the initial lattice are found by simple addition of these values from Krishna-Iyer joins tests performed separately upon each of the four smaller, independent lattices. The same principle extends to decompositions into nine independent lattices by third nearest neighbors, 16 independent lattices by fourth nearest neighbors, and so on. A simplifying feature is that the same sets of nearest neighbor decompositions invariably arise regardless of the starting point. Example calculations and results from a 19 × 28 = 532-tree lattice of 17 y (postplanting age) red pine (Pinus resinosa) are presented for first nearest neighbors (the standard Krishna-Iyer test), and for second and third nearest neighbors. In this example analysis, pockets of soils inimical to early survival are indicated by positive associations of first-year deaths across first, second and third nearest neighbors. Some possible “wave” effects are suggested by such recurrent associations as the largest trees with the empty spaces left by first-year deaths, as first and third nearest neighbors, but not as second neighbors.

Twelve wetlands (7 recently restored; 5 reference) in central and southern Minnesota were monitored during the 1998 breeding season to assess colonization of recently restored wetlands by amphibians, compare the amphibian fauna to that of reference wetlands and identify important factors influencing the probability of colonization. Eight amphibian species rapidly colonized recently restored wetlands and established breeding populations. Reference wetlands were inhabited by twelve species, including four not found in restored wetlands (Ambystoma laterale, Notophthalmus viridescens, Pseudacris crucifer and Rana clamitans). Most local habitat variables, such as water chemistry or aquatic vegetation cover, were not influential in determining species richness patterns in recently restored wetlands. Size and spatial isolation of restored wetlands, however, were important predictors of species richness. Habitat suitability also influenced the probability of colonization for some species. The results of this study indicate that restored wetlands are valuable habitat for at least a subset of the amphibian fauna of this region and that wetland size, isolation and habitat suitability all influence colonization success.

We searched for areas of syntopy between hybrid-derived clonal complexes A and B of Cnemidophorus laredoensis and both of their gonochoristic progenitors, C. sexlineatus and C. gularis, in Texas and México from 1983 through 2000. We discovered that all sites inhabited syntopically or separately by these two clonal complexes of lizards are contained within the vast binational range of C. gularis, a widely tolerant species that is either present, or exists in neighboring plant communities, at all sites inhabited by these parthenogenetic forms. Conversely, the only sites of syntopy between C. laredoensis A and B and C. sexlineatus discovered during our study were clustered in a small area of northern Webb County, Texas. The basis for extensive syntopy between C. laredoensis A and B and maternal progenitor C. gularis and limited syntopy between these parthenogenetic forms and paternal progenitor C. sexlineatus includes components of both species-specific ecological adaptations and zoogeographical histories.

We examined home range size and habitat use of four reproductively active male Rafinesque's big-eared bats (Corynorhinus rafinesquii) in an area of the Upper Coastal Plain of South Carolina during August and September 1999. Corynorhinus rafinesquii had biphasic activity patterns, with most foraging activity occurring during the first 4 h after sunset and 2 h before sunrise. Mean home range size calculated using the adaptive kernel method with a 95% use distribution was 93.1 ha. Although large contiguous tracts of mature bottomland hardwoods were common in the study area, most foraging activity occurred in young pine stands. Only 9% of foraging areas were in bottomland hardwoods.

Fecal samples from 54 Gunnison's prairie dogs (Cynomys gunnisoni) from Albuquerque, NM were analyzed for the presence of coccidia and all were positive. They were then relocated to an abandoned prairiedog town on the Sevilleta Long Term Ecological Research (LTER) site. Six Eimeria species, E. callospermophili, E. cynomysis, E. pseudospermophili (new host record), E. spermophili, E. ludoviciani and E. vilasi (new host record) were found in Albuquerque animals, but only 2 species, E. callospermophili and E. vilasi were present in relocated hosts. A significant (P < 0.05) reduction was seen in the prevalence of E. vilasi (72% vs. 13%) and in the prevalence of infections (P < 0.05) with 2 or more Eimeria species (39% vs. 4%) in pre- and postrelocation animals. To assess the impact of the introduction of C. gunnisoni on the resident rodent population, feces were collected from 6 species of rodents. Five Eimeria species, E. arizonensis (Reithrodontomys), E. chobotari (Dipodomys, Perognathus), E. liomysis (Dipodomys), E. mohavensis (Dipodomys) and E. reedi (Perognathus) were found. We found no evidence of coccidia transfer among introduced and resident rodent species.

We examined survival and cause-specific mortality of 37 adult coyotes using radio telemetry in central Mississippi during 1993–1997. Annual survival did not differ between sexes or across years, but did among seasons. Mean survival probabilities (sexes combined) were greater during pup-rearing (0.98) than breeding (0.84) or winter (0.89). Harvest by sport hunters was the most prevalent of known mortalities. Our findings indicate that southeastern coyotes have greater survival probabilities than populations in other regions due to lower harvest levels.

Small mammals locate buried wet seeds more efficiently than buried dry seeds. This may be attributable to emission of volatile compounds by the seeds. To test this hypothesis I measured emission of volatile compounds from seeds of three plant species (Pinus contorta, Purshia tridentata and Achnatherum hymenoides) under wet and dry conditions using solid phase micro-extraction, gas chromatography/mass spectrometry headspace analysis. Seeds responded in two ways: (1) wet seeds released different, generally greater, amounts of volatile gas than dry seeds and (2) wet seeds and dry seeds released different compounds. Pinus contorta seeds release greater amounts of three compounds when wet; Purshia tridentata seeds release two compounds when dry that are not released when wet, and release increased amounts of two compounds when wet, and increased amounts of two compounds when dry; Achnatherum hymenoides releases at least 22 compounds, one of which is released in large concentrations when wet. These data suggested two mechanisms by which small mammals locate buried seeds. First, small mammals may be sensitive to release of differing concentrations of volatile compounds by seeds. Second, small mammals may be sensitive to compounds released by wet seeds that are not released by dry seeds. Ability of seeds to survive depredation by granivores may be an adaptive trait influenced by natural selection.

The katydids Orchelimum nigripes and O. pulchellum (Orthoptera: Tettigoniidae) have a largely allopatric distribution in the eastern United States, but hybridization between these species has been well documented in two contact zones. I used animals from populations just outside a narrow, recently formed upstream-downstream hybrid zone along the Potomac River near Washington, D.C., in laboratory mate-choice trials to examine the possible importance of differential patterns of mate preference in determining the structure and dynamics of this hybrid zone. Offered a choice between a male of each species, O. nigripes females showed an extreme preference for conspecific mates, but O. pulchellum females showed no clear preference. This asymmetry in mate discrimination may contribute to the apparently ongoing replacement along the Potomac of O. pulchellum by O. nigripes in the wake of a moving hybrid zone.