The American Midland Naturalist

Articles from Vol. 142, No. 2, October

Age-Related Fecundity in Four Taxa of Western Shrews (Sorex Spp.)
ABSTRACT-We tested the hypotheses that fecundity in four taxa of Sorex declines with age and that older individuals enter a postreproductive state. As the teeth erode in shrews the dentary shortens and masticatory muscles increase in mass, thereby maintaining...
Allozyme Perspective on Genetic Variation in a Threatened Percid Fish, the Leopard Darter (Percina Pantherina)
ABSTRACT.-Genetic variation was assessed with protein electrophoresis for seven populations of the leopard darter, Percina pantherina, a species restricted to five rivers in the Little River System of southwestern Arkansas and southeastern Oklahoma....
A New Elevation Record for the Red Tree Vole in Oregon: Implications for National Forest Management
ABSTRACT.-We document the capture of a red tree vole (Arborimus longicaudus) at a new location and higher elevation than previously recorded for the species. This finding shows that the red tree vole occurs outside the current survey and management areas...
Bumblebee Foraging Responses to Variation in Floral Scent and Color in Snapdragons (Antirrhinum: Scrophulariaceae)
ABSTRACT.-We examined the roles of floral scent and color in attracting bumblebees (Bombus spp.) to snapdragon flowers (Antirrhinum, Sonnet cultivar). Corolla color differences covaried with differences in floral scent emissions in two inbred lines of...
Changes in the Distribution of Freshwater Mussels (Unionidae) in the Upper Susquehanna Riber Basin, 1955-1965 to 1996-1997
ABSTRACT.--In 1955-1965, the streams and rivers of the upper Susquehanna River basin in New York were surveyed for unionid mussels. We resurveyed unionid populations at the same sites in 1996-1997 to determine whether populations had declined and whether...
Contrasting Soil Seed-Bank Dynamics in Relation to Local Recruitment Modes in Two Clonal Shrubs, Rhus Aromatica Ait. and R. Glabra L. (Anacardiaceae)
ABSTRACT.--Soil seed bank dynamics, greenhouse seed germination and field seedling survival were compared in the weakly-clonal shrub Rhus aromatica Ait. and the strongly clonal shrub R. glabra L. (Anacardiaceae). Although both species had persistent...
Deforestation, Reforestation and Forest Fragmentation on the Upper Coastal Plain of South Carolina and Georgia
ABSTRACT.-Rates of deforestation and reforestation were measured using Landsat Multispectral Scanner data for a 100-km by 100-km section of the Upper Coastal Plain of South Carolina and Georgia. Landsat data from 1974, 1979, 1984, 1988 and 1991 were...
Demographic Performance of a Rare California Endemic, Chorizanthe Pungens Var. Hartwegiana (Polygonaceae)
ABSTRACT.-Managing and understanding the ecology of endemic plants depends upon understanding the habitat limitations of these highly restricted species. Using transplant experiments we quantified the demographic performance of an endangered annual plant...
Distributions and Selected Aspects of the Life Histories and Habitat Associations of the Crayfishes Orconectes Peruncus (Creaser, 1931) and O. Quadruncus (Creaser, 1933) in Missouri
ABSTRACT.-The crayfishes Orconectes peruncus and O. quadruncus are endemic to the upper St. Francis River drainage in southeastern Missouri, and were classified as threatened in a recent analysis of the conservation status of crayfishes in the United...
Diversity of Arthropod Responses to Host-Plant Water Stress in a Desert Ecosystem in Southern New Mexico
ABSTRACT.-Pre-5ous studies of insect-plant interactions have produced the contradictory Plant Stress Hypothesis (that stressed plants are more suitable hosts for phytophages) and Plant Vigor Hypothesis (that vigorous plants are more suitable hosts for...
Effect of Zebra Mussels, Dreissena Polymorpha, on Macroinvertebrates in a Lake-Outlet Stream
ABSTRACT.-Zebra mussels, Dreissena polymorpha, increase macroinvertebrate abundance on hard substrata in lakes and large rivers because they enhance surface area, substratum heterogeneity and the accumulation of benthic organic matter (BOM). We tested...
Effects of Lek Age on Age Structure and Attendance of Lesser Prairie-Chickens (Tympanuchus Pallidicinctus)
ABSTRACT.-We used data from lesser prairie-chickens captured on leks to test the hypothesis that age structure of attending birds is reflected in lek age (i.e., years of continuous attendance). As leks become older the age structure of attending birds...
Foods of American Badgers in West-Central Minnesota and Southeastern North Dakota during the Duck Nesting Season
ABSTRACT.-Although the American badger (Taxidea taxus) is common in grasslands and preys on a wide diversity of foods including birds, little is known about badger diet in areas where nesting ducks are common. Small mammals, primarily Mundae and Geomyidae,...
Grassland Soil Depressions: Relict Bison Wallows or Inherent Landscape Heterogeneity?
ABSTRACT.-Wallows are circular soil depressions created by repeated bison (Bison bison L.) dust-bathing. Despite more than a century of bison absence from the Great Plains and lack of evidence on wallow persistence, many studies have classified grassland...
Habitat Quality, Population Density and Habitat-Specific Productivity of Red-Winged Blackbirds (Agelaius Phoeniceus) in Boulder County, Colorado
ABSTRACT.-I monitored 382 red-4lnged blackbird (Agelaius phoeniceus) nests in natural (wetlands and tallgrass prairie) and human-disturbed (hayfields, roadside ditches) habitats in the vicinity of Boulder, Colorado during 1996 and 1997. I counted blackbirds...
Habitat Relationships among Grasshoppers (Orthoptera: Acrididae) at the Western Limit of the Great Plains in Colorado
ABSTRACT.-We measured grasshopper densities on 66 shortgrass, mixed grass, tallgrass and hayfield plots on Boulder, Colorado, open space in 1995-1996. Grasshoppers as a group, and most species individually, were more abundant on relatively sparse short...
Introduction and Range Expansion of Nonnative Red Foxes (Vulpes Vulpes) in California
ABSTRACT: Predation on endangered species by nonnative red foxes (Vulpes vulpes) and the resulting controversy over red fox control efforts in California prompted our investigation of the introduction and range expansion of the red fox in California....
Roost Selection, Population Size and Habitat Use by a Colony of Rafinesque's Big-Eared Bats (Corynorhinus Rafinesquii)
ABSTRACT.-- Rafinesque's big-eared bat (Corynorhinus rafinesquii) is a species of concern throughout much of its range, with limited information available on the life history of this rare bat. We tracked patterns of population size, measured roost temperatures...
Studies of Ballooning and Resulting Patterns of Locally Contagious Distribution of the Bagworm Tyridopteryx Ephemeraeformis (Haworth) (Lepidoptera: Psychidae)
ABSTRACT.-A series of field studies was stimulated by the unexpected finding of a band of junipers (Juniperus virginiana) bearing heavy infestations of bagworms, the band running south-southwest to north-northeast through a woodlot (near Norman, OK)...
Succession, Sapling Density and Growth in Canopy Gaps along a Topographic Gradient in a Second Growth East Tennessee Forest
ABSTRACT.-Canopy gaps in a second growth forest in East Tennessee were studied to document succession, sapling species partitioning in individual gaps and possible sapling adaptations for gap colonization. Ten gaps (64 to 309 m^sup 2^, mean = 186 m^sup...
Temporal and Spatial Patterns of Woody Plant Establishment in Michigan Old Fields
ABSTRACT.-We investigated temporal and spatial patterns of woody plant establishment in the first 7 y of succession in southwest Michigan old fields. From the 2nd to the 7th y following agricultural abandonment we conducted annual demographic surveys...