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Articles 1 - 11 of 11

Full-Text Articles in Life Sciences

Differential Demographic Responses Of Two Sympatric Turtle Species To Anthropogenic Disturbance, Sarah M. Mitchell Jan 2015

Differential Demographic Responses Of Two Sympatric Turtle Species To Anthropogenic Disturbance, Sarah M. Mitchell

Graduate Theses and Dissertations

Species extinction is a major crisis facing the biological world today. Conservation biologists are striving to determine what factors contribute to species declines. Many of these factors are anthropogenic, with issues such as climate change, invasive species, pollution, and habitat alteration and destruction concurrently affecting populations. Turtles have proven to be particularly vulnerable; among the vertebrate taxa, turtles are the most endangered. These studies seek to determine the effects of anthropogenic habitat alteration on two sympatric species of turtles: the painted turtle (Chrysemys picta) and the ornate box turtle (Terrapene ornata) using fecundity, survival estimates, and/or capture-mark-recapture data from ...


Fire Induced Reproductive Mechanisms Of A Symphoricarpos (Caprifoliaceae) Shrub After Dormant Season Burning, John Derek Scasta, David M. Engle, Ryan N. Harr, Diane M. Debinski Dec 2014

Fire Induced Reproductive Mechanisms Of A Symphoricarpos (Caprifoliaceae) Shrub After Dormant Season Burning, John Derek Scasta, David M. Engle, Ryan N. Harr, Diane M. Debinski

Ecology, Evolution and Organismal Biology Publications

Background: Symphoricarpos, a genus of the Caprifoliaceae family, consists of about 15 species of clonal deciduous shrubs in North America and 1 species endemic to China. In North American tallgrass prairie, Symphoricarpos orbiculatus (buckbrush) is the dominant shrub often forming large colonies via sexual and asexual reproductive mechanisms. Symphoricarpos shrubs, in particular S. orbiculatus, use a unique sexual reproductive mechanism known as layering where vertical stems droop and the tips root upon contact with the soil. Because of conflicting societal values of S. orbiculatus for conservation and agriculture and the current attempt to restore historical fire regimes, there is a ...


Terrestrial Arthropod Community And Indicators Of Biotic Integrity For Iowa Tallgrass Prairie, Jessica Marie Orlofske Jan 2008

Terrestrial Arthropod Community And Indicators Of Biotic Integrity For Iowa Tallgrass Prairie, Jessica Marie Orlofske

Retrospective Theses and Dissertations

The tallgrass prairie has become one of the most endangered ecosystems in North America. Thus, there have been attempts to restore and reconstruct native tallgrass prairie. Arthropods, the most diverse taxonomic group on the prairie, have not received adequate attention. A comprehensive arthropod survey in Iowa prairies has not been attempted since the 1930's, and therefore lacks information regarding recent prairie restoration efforts. Arthropods can also provide valuable information related to ecosystem function or biotic integrity when used as bioindicators. However, effective, reliable arthropod bioindicators have not been clearly identified. A survey of arthropods using sweep net transects was ...


The Importance Of Host Fish In Long Range Transport Of Unionids In Large Rivers , Daelyn Adele Woolnough Jan 2006

The Importance Of Host Fish In Long Range Transport Of Unionids In Large Rivers , Daelyn Adele Woolnough

Retrospective Theses and Dissertations

Freshwater mussels (Family: Unionidae) are the most imperiled faunal group in North America, yet little is known about factors that influence their distribution in rivers and lakes---especially over large geographic areas. They have a unique life cycle that includes an obligate parasite stage on fish. Throughout their life spans, long range or upstream transport is principally accomplished during the parasitic stage. This brief parasitic phase has lasting effects on adult mussel ecology---particularly in influencing their distribution. The movement of host fish occurs on large scales (e.g., >100m) and both their distribution and abundance likely contribute to the spatial patterns ...


Behaviorally-Induced Periodic Cooling Of Avian Embryos , Christopher Robin Olson Jan 2006

Behaviorally-Induced Periodic Cooling Of Avian Embryos , Christopher Robin Olson

Retrospective Theses and Dissertations

For many bird embryos, periodic cooling occurs when the incubating adult leaves the nest to forage, but the effects of periodic cooling on embryo growth, yolk use and metabolism are poorly known. To address this question I conducted incubation experiments on eggs of zebra finches (Taeniopygia guttata ) that were frequently cooled and then rewarmed or were allowed to develop at a constant temperature. After 12 days of incubation, embryo mass and yolk reserves were less in eggs that experienced periodic cooling, compared to controls incubated constantly at 37.5°C. Embryos that regularly cooled to 20°C had higher mass-specific ...


Corridors And Some Ecological And Evolutionary Consequences Of Connectivity , John Lee Orrock Ii Jan 2004

Corridors And Some Ecological And Evolutionary Consequences Of Connectivity , John Lee Orrock Ii

Retrospective Theses and Dissertations

By connecting disjunct patches, corridors may offset the effects of fragmentation by promoting gene flow and population persistence. However, the ultimate effect of corridors on a focal species may hinge upon two considerations: how corridors may affect ecological interactions that impinge upon that species, and how corridors might affect the fixation of novel alleles that ultimately determine fitness and persistence. Using an experimental landscape, I show that corridor-mediated changes in patch shape change seed predation in connected and unconnected patches, and shift the behavior, abundance, and distribution of seed predators. Rodent seed predators removed more seeds in connected patches, arthropod ...


Environmental Quality And Fish Community Ecology In An Agricultural Mountain Stream System Of Taiwan , Ching-Ming James Wang Jan 1989

Environmental Quality And Fish Community Ecology In An Agricultural Mountain Stream System Of Taiwan , Ching-Ming James Wang

Retrospective Theses and Dissertations

A 1.5 year environmental and faunal analysis was conducted in headwater streams of the upper Ta-chia River in mountainous central Taiwan. The area had distinct wet and dry seasons owing to monsoonal-typhoonal rainfall patterns. Compared to natural stream areas, agriculturally impacted reaches had greater discharge fluctuation, warmer temperatures, higher turbidity, increased nutrient loads, and reduced bedform diversity;Stream biotic communities varied according to local habitat characteristics. Coldwater algae existed mainly within natural stream reaches while eutrophication indicators occurred abundantly at agriculturally impacted sites. Large-bodies shredder-collector and predatory insects inhabited natural stream areas while smaller scraper-collectors were dominant in an ...


Range Ecology Of Bison On Mixed Grass Prairie At Wind Cave National Park, Jewel Kay Popp Jan 1981

Range Ecology Of Bison On Mixed Grass Prairie At Wind Cave National Park, Jewel Kay Popp

Retrospective Theses and Dissertations

No abstract provided.


Breeding Biology Of American Coots In Relation To Age , Richard Dwight Crawford Jan 1975

Breeding Biology Of American Coots In Relation To Age , Richard Dwight Crawford

Retrospective Theses and Dissertations

No abstract provided.


Aquatic Invertebrate Abundance In Relation To Changing Marsh Conditions , David Kenneth Voigts Jan 1973

Aquatic Invertebrate Abundance In Relation To Changing Marsh Conditions , David Kenneth Voigts

Retrospective Theses and Dissertations

No abstract provided.


Prairie Flora On The Missouri River Bluffs Of Western Iowa , John Barstow Morrill Jr. Jan 1953

Prairie Flora On The Missouri River Bluffs Of Western Iowa , John Barstow Morrill Jr.

Retrospective Theses and Dissertations

In western Iowa, from Sioux City south to Hamburg, the Missouri River flood plain is bordered by a series of abrupt loess bluffs. Because of the wide variability in exposure, because of the characteristic wind-deposited loess and because of the accessability to river migration routes, the bluffs possess a diverse, albeit characteristic flora. Investigations of localized or specialized ecological niches frequently yield not only floristic data but insight into historical development and migration movements of both individual species and floristic units. For instance, McLaughlin (1932) in his study of the sand barren flora of northwest Wisconsin was able to show ...