The American Midland Naturalist

Articles from Vol. 138, No. 1, July

An 18-Year Study of Litterfall and Litter Decomposition in a Northeast Iowa Deciduous Forest
ABSTRACT.-Most studies of deciduous forest litter decomposition have been no longer than 3 yr. The study reported here includes 18 yr of annual measurement of litterfall and litter disappearance as an index of decomposition during a period of considerable...
Aquatic Seed Dispersal and Its Implications in Cirsium Vinaceum, a Threatened Endemic Thistle of New Mexico
ABSTRACT.-Cirsium vinaceum (Asteraceae), an endemic thistle of the Sacramento Mountains, New Mexico, is federally listed as threatened. It occurs in spring and streamside habitats; individual patches of plants vary widely in size and in distance from...
Changes in Trumpeter Swan (Cygnus Buccinator) Activities from Winter to Spring in the Greater Yellowstone Area
JOHN R SQUIRES U.S. Forest Service, Rocky Min. Forest and Range Experiment Station, 222 S. 22nd Street Laramie, Wyoming 82070 AND STANLEY H. ANDERSON U.S. Fish and Wildlife Service, Wyoming Cooperative Fish and Wildlife Research Unit, P.O. Box 3166,...
Demography and Life History Characteristics of the Rare Kachina Daisy (Erigeron Kachinensis, Asteraceae)
ABSTRACT.-Erigeron kachinensis is a rare endemic of the Colorado Plateau regions of southeastern Utah and southwestern Colorado. It occurs in small, isolated alcoves (recessed areas in canyon walls) at seeps arising along canyon walls in sandstone substrates....
Do Plants Derived from Seeds That Readily Germinate Differ from Plants Derived from Seeds That Require Forcing to Germinate? A Case Study of the Desert Mustard Lesquerella Fendleri
ROBERT J. CABIN1,2, ANN S. EVANS AND RANDALL J. MITCHELL3 Department of Biology, University of New Mexico, Albuquerque 87131-1091 ABSTRACT.-We compared the performance of plants of the desert mustard Lesquerella fendleri derived from seeds that readily...
Drifting Macrophytes as a Mechanism for Zebra Mussel (Dreissena Polymorpha) Invasion of Lake-Outlet Streams
ABSTRACT.-Veligers spawned from lake populations are thought to be the major means for spread of zebra mussels (Dreissena polymorpha) into outflowing rivers. We hypothesized, however, that adult zebra mussels attached to lake macrophytes could enter...
Effects of Horning and Rubbing Behavior by Bison (Bison Bison) on Woody Vegetation in a Tallgrass Prairie Landscape
ABSTRACT.-Horning and rubbing behaviors of American bison (Bison bison) and their effects on woody vegetation were investigated for 2 yr on a herd of 300+ animals reintroduced to a 1973-ha tallgrass prairie site in Oklahoma. Horning and rubbing activity...
Effects of Urbanization on Brown Trout Salmo Trutta, Other Fishes and Macroinvertebrates in Valley Creek, Valley Forge, Pennsylvania
STANLEY J. KEMP1 AND JAMES R. SPOTILA1 ABSTRACT.-We determined the effects of urbanization on fish and benthic macroinvertebrate communities of Valley Creek and its tributary, Little Valley Creek, in southeastern Pennsylvania. Brown trout (Salmo trutta)...
External Morphology of Spermatozoa and Spermatozeugmata of the Freshwater Mussel Truncilla Truncata (Mollusca: Bivalvia: Unionidae)
ABSTRACT.-Truncilla truncata males release spherical aggregates of spermatozoa, called spermatozeugmata, at spawning. Sperm aggregates from other bivalve species have been described, but few detailed studies exist of the morphology of unionid spermatozeugmata...
Ground Beetle (Coleoptera: Carabidae) Activity Density and Cummunity Composition in Vegetationally Diverse Corn Agroecosystems
DANIEL M. PAWK1 Department of Biological Sciences, Bowling Green State University, Bowling Green, Ohio 43403 FOSTER F. PURRINGTON Department of Entomology, The Ohio State University, Columbus 43210 CHARLES E. WILLIAMS Department of Biology, Clarion University...
Growth and Survival of Polygonum Aviculare L. at a Brine-Contaminated Site in Southeastern Ohio
ABSTRACT.-Populations of Polygonum aviculare from low-salinity and high-salinity sites at a brine spill location in Ohio were studied to determine the effects of edaphic factors and intraspecific competition on seed germination, growth and survival....
Growth Rate, Body Size, Sexual Dimorphism and Morphometric Variation in Four Populations of Painted Turtles (Chrysemys Picta Bellii) from Nebraska
JOHN W. ROWE' School of Biological Sciences, University of Nebraska-Lincoln, Lincoln 68588 ABSTRACT.-I studied variation in individual growth rate, body size, sexual size dimorphism and morphometry in two sandhill lake and two Platte River floodplain...
Historic and Current Amphibian and Reptile Distributions in the Island Region of Western Lake Erie
ABSTRACT.-Records of amphibians and reptiles from the island region of western Lake Erie (Essex County, Ontario; Erie and Ottawa counties, Ohio) span more than a century and include 50 species, 35 of which have been recorded from at least one of 19 islands....
Identification of a Fish Host of the Inflated Heelsplitter Potamilus Inflatus (Bivalvia: Unionidae) with a Description of Its Glochidium
KEVIN J. ROE1 ANDREW M. SIMONS ABSTRACT.-A survey of the fishes of the Black Warrior River was undertaken to determine fish host(s) of the federally threatened inflated heelsplitter, Potamilus inflatus. Seven hundred-twenty individual fishes representing...
Northern Redistribution of Freshwater Pearly Mussels (Bivalvia: Unionoidea) during Wisconsin Deglaciation in the Sothern Glacial Lake Agassiz Region: A Review
DANIEL L. GRAF Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts 02138 and Department of Biology Northeastern University, Boston, Massachusetts 02115 ABSTRACT.-The chronology of the reinvasion of freshwater pearly mussels (Bivalvia:...
Polymorphic Floral Traits in Linaria Canadensis (Scrophulariaceae)
ABSTRACT.-This study examined several aspects of a previously unreported flower color polymorphism in the annual plant Linaria canadensis. Natural populations in southeastern Georgia contained mainly two petal color morphs: the 'dark' purple morph and...
Population Characteristics of Coyotes (Canis Latrans) in the Nothern Chihuahuan Desert of New Mexico
LAMAR A. WINDBERG,1 STEVEN M. EBBERT2 AND BRIAN T. KELLY3 ABSTRACT.-We estimated demographic variables for a coyote (Canis latrans) population in the northern Chihuahuan Desert in spring 1991. Indices of coyote abundance indicated that the population...
Root System Differences among Species: Implications for Early Successional Changes in Forests of Western Oregon
ABSTRACT.-Differences in root systems among species may contribute to compositional changes during succession. We excavated all belowground parts of species in an early successional community 2-3 yr after logging and burning of an old Pseudotsuga menziesii...
Scale-Dependent Habitat Selection by the Darkling Beetle Eleodes Hispilabris (Coleoptera: Tenebrionidae)
ABSTRACT.-Habitat selection in the darkling beetle Eleodes hispilabris Say (Coleoptera: Tenebrionidae) on the shortgrass prairie of the central United States was nonrandom at both a broad (km2) and a fine (cm2) scale, relative to the abundance of broadly...
Shell Strength of Mud Snails (Ilyanassa Obsoleta) May Deter Foraging by Diamondback Terrapins (Malaclemys Terrapin)
ABSTRACT.-Diamondback terrapins (Malaclemys terrapin) do not eat the common and abundant mud snail (Ilyanassa obsoleta) even though terrapin diets are dominated by similarly sized gastropods. To resolve this paradox, we tested a structural defense hypothesis...
Spatial Variation in Rates of Seed Removal by Harvester Ants (Pogonomyrmex Occidentalis) in a Shrub-Steppe Ecosystem
JOHN F. MULL1 AND JAMES A. MACMAHON Department of Biology and Ecology Center Utah State University, Logan 84322 ABSTRACT: Spatial variability in the intensity of plant-animal interactions can have important implications for plant community structure....
Taxonomic Status and Distribution of the Lamprey Ichthyomyzon Cf. Gagei
J. LYONS Wisconsin Department of Natural Resources, 1350 Femrite Drive, Monona 53716 P. A. COCHRAN AND M. E. SNEEN1 Division of Natural Sciences, St. Norbert College, DePere, Wisconsin 54115 ABsTRACT.-A nonparasitic lamprey of uncertain taxonomic status,...
Understory Light Regime, Shrub Layer and Sand Pine (Pinus Clausa) Regeneration in Four Scrub Stands
ABSTRACT.-Estimates of direct and indirect light regime were derived from hemispherical canopy photographs for four Florida sand pine (Pinus clausa) scrub stands. Shrub foliageheight density and sand pine regeneration were tallied in 4 me cells around...