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Factors Affecting Parental Investment Strategies In Male Waterbugs, Scott Kight Jan 1991

Factors Affecting Parental Investment Strategies In Male Waterbugs, Scott Kight

Masters Theses

Male giant waterbugs (Belostoma flumineum Say) brood eggs oviposited on their dorsi by conspecific females. Preliminary observations indicate that viable egg pads are sometimes discarded before hatching. Theory predicts that such behavior should occur only if costs incurred by brooding exceed benefits of hatching the egg pad. The amount of paternal investment per pad should be similar for both large and small pad sizes, but as egg pads become smaller, investment per egg increases. Thus, smaller pads should be more likely to be discarded unhatched than larger ones. Similarly, egg pads containing inviable eggs should also be more frequently …


Wildlife Corridors In The Wheatbelt, Richard Hobbs, Denis Saunders Jan 1991

Wildlife Corridors In The Wheatbelt, Richard Hobbs, Denis Saunders

Journal of the Department of Agriculture, Western Australia, Series 4

Native vegetation in the Western Australian wheatbelt now persists mostly in small areas that remained uncleared for various reasons. (See 'Remnant vegetation on farms is a valuable resource' on page 43.) On their own, most of these remnant areas are difficult to manage, and too small to retain viable populations of many of the birds and other animals found in the wheatbelt. These patches of vegetation can be linked by wildlife corridors, which may increase the ability of the wildlife to move about and persist in the area


Distribution, Scutellation, And Reproduction In The Queen Snake, Regina Septemvittata (Serpentes: Colubridae), From Arkansas, Stanley E. Trauth Jan 1991

Distribution, Scutellation, And Reproduction In The Queen Snake, Regina Septemvittata (Serpentes: Colubridae), From Arkansas, Stanley E. Trauth

Journal of the Arkansas Academy of Science

The queen snake, Regina septemvittata, has a disjunct portion of its distribution in Arkansas. This rare, crayfish-eating species is best known from only a few isolated populations from several major streams that flow out of the Boston Mountains of the Ozark Plateau. A field study of this species was conducted during the summer of 1990, and only 4 specimens were documented. Gravid females were collected in July; sperm production was also noted in July. Parturition presumably takes place in August or early September. This species may qualify as threatened or endangered in Arkansas.


Aggressive Interactions Between Male Cotton Mice (Peromyscus Gossypinus) And Male Texas Mice (P. Attwateri), John A. Peppers, David W. Royal, Gary A. Heidt Jan 1991

Aggressive Interactions Between Male Cotton Mice (Peromyscus Gossypinus) And Male Texas Mice (P. Attwateri), John A. Peppers, David W. Royal, Gary A. Heidt

Journal of the Arkansas Academy of Science

No abstract provided.


Introgression Of Coyote Mitochondrial Dna Into Sympatric North American Gray Wolf Populations, Niles Lehman, Andrew Eisenhawer, Kimberly Hansen, L. David Mech, Rolf O. Peterson, Peter J. P. Gogan, Robert K. Wayne Jan 1991

Introgression Of Coyote Mitochondrial Dna Into Sympatric North American Gray Wolf Populations, Niles Lehman, Andrew Eisenhawer, Kimberly Hansen, L. David Mech, Rolf O. Peterson, Peter J. P. Gogan, Robert K. Wayne

United States Geological Survey, Northern Prairie Wildlife Research Center: Publications

Mitochondrial DNA (mtDNA) genotypes of gray wolves and coyotes from localities throughout North America were determined using restriction fragment length polymorphisms. Of the 13 genotypes found among the wolves, 7 are clearly of coyote origin, indicating that genetic transfer of coyote mtDNA into wolf populations has occurred through hybridization. The transfer of mtDNA appears unidirectional from coyotes into wolves because no coyotes sampled have a wolf-derived mtDNA genotype. Wolves possessing coyote-derived genotypes are confined to a contiguous geographic region in Minnesota, Ontario, and Quebec, and the frequency of coyote- type mtDNA in these wolf populations is high (> 500%). The …


Searching Image In The Pigeon: A Test Of Three Hypothetical Mechanisms, Alan B. Bond, Donald A. Riley Jan 1991

Searching Image In The Pigeon: A Test Of Three Hypothetical Mechanisms, Alan B. Bond, Donald A. Riley

Papers in Behavior in Biological Sciences

The searching image hypothesis was originally proposed to account for the observation that animals selecting among disparate foods often consume an excess of the more common types. The hypothesis states that animals searching for a particular cryptic food item focus on visual features that are characteristic of that item, thereby facilitating its discrimination from the background. A change in stimulus discriminability is not, however, the only feasible explanation for the effect. One alternative is a simple change in response bias, an increased predisposition to respond to food-related stimuli. Another possible hypothesis derives from the fact that the amount of time …


Social Behavior And The Ontogeny Of Foraging In The Kea (Nestor Notabilis), Judy Diamond, Alan B. Bond Jan 1991

Social Behavior And The Ontogeny Of Foraging In The Kea (Nestor Notabilis), Judy Diamond, Alan B. Bond

Papers in Behavior in Biological Sciences

Kea are omnivorous parrots endemic to the high mountains of the South Island of New Zealand. Over a two-year period, we recorded quantitative behavioral data from 38 banded male kea foraging at a refuse dump outside Arthur's Pass National Park and analyzed the effects of social factors on the ontogeny of foraging. Members of the four distinguishable age classes — fledglings, juveniles, subadults, and adults — displayed characteristic differences in foraging ability and in the social behavior used to obtain access to resources. Adults performed most of the excavation that uncovered new food resources. Fledglings explored and manipulated objects almost …


Sexual Dimorphism In The Kea Nestor Notabilis, Alan B. Bond, Kerry-Jayne Wilson, Judy Diamond Jan 1991

Sexual Dimorphism In The Kea Nestor Notabilis, Alan B. Bond, Kerry-Jayne Wilson, Judy Diamond

Papers in Behavior in Biological Sciences

Morphological differences between the sexes in Keas Nestor notabilis were quantified from a sample of 86 sexed museum specimens, nine sexed zoo captives and 129 live, wild-caught birds. The results demonstrate that Kea are sexually dimorphic. Males are about 5% larger than females in linear measurements of body size and their upper bills are on average 12-14% longer, with a slightly larger radius of curvature. The dimorphism in bill size was statistically independent of the difference in overall body size, suggesting the possibility of intersexual differences in niche utilisation. Culmen length appears to be a useful means for distinguishing sexes …


Eumeces Septentrionalis (Prairie Skink): Piscivory., Louis A. Somma Jan 1991

Eumeces Septentrionalis (Prairie Skink): Piscivory., Louis A. Somma

Papers in Herpetology

The prairie skink is a North American lizard characterized by a diet that is primarily insectivorous (Breckenridge 1943. Amer. MidI. Nat. 29:591-606). Fish have not been previously recorded as a food item (reviewed in Somma and Cochran 1989. Great Basin Nat. 49:525-534). On 3 June 1990 between 0930 and 1030 h, six Eumeces septentrionalis (three gravid females, one male, and two juveniles) were captured from amongst riprap and beneath stone slabs on the earthen dam forming the windward shoreline of Burchard lake, Pawnee Co., Nebraska (T.12N., R.10E., Sec. 4). The three females and one juvenile were placed in the …


Herbivore-Plant Interaction: Temperate And Tropical Patterns: Review Of Peter W. Price Et Al., Eds., Plant-Animal Interactions: Evolutionary Ecology In Tropical And Temperate Regions, Svata M. Louda Jan 1991

Herbivore-Plant Interaction: Temperate And Tropical Patterns: Review Of Peter W. Price Et Al., Eds., Plant-Animal Interactions: Evolutionary Ecology In Tropical And Temperate Regions, Svata M. Louda

Svata M. Louda Publications

This book is an interesting compendium of old and new thoughts on the interactions of herbivores, especially insect herbivores, with plants; the title, however, seems a bit more ambitious. Pollination, for example, surely an important "plant-animal interaction" in both temperate and tropical regions, is mentioned only in passing. This most likely reflects the book's origins in an international symposium on the evolutionary ecology of tropical herbivores. As usual in such a collection of papers, the papers vary in purpose, length, and new insights; even papers that are reviews of previously published information, however, seem to me to present the authors' …


Dietary And Parasitological Analysis Of Coprolites Recovered From Mummy 5, Ventana Cave, Arizona, Karl Reinhard, Richard H. Hevly Jan 1991

Dietary And Parasitological Analysis Of Coprolites Recovered From Mummy 5, Ventana Cave, Arizona, Karl Reinhard, Richard H. Hevly

Karl Reinhard Publications

Four coprolites were excavated with Burial 5 at Ventana Cave. a partially mummified five-year-old child. Two coprolites were granular and dark in color and two were fibrous and light in color. The coprolites are remains of the child's intestinal contents and were submitted for dietary and parasitological analysis. No parasites were found. The fibrous coprolites proved to be remains of highly masticated mesquite pods (Prosopis). The granular coprolites consist of seeds of saguaro cactus (Carnegiea gigantea). Pollen analysis reveals two dietary pollen types, both derived from cactus. No evidence of cultivated plants except for a trace amount of …


Littoral And Limnetic Zooplankton Communities In Lake Mead, Nevada-Arizona, Usa, Patrick J. Sollberger, Larry J. Paulson Jan 1991

Littoral And Limnetic Zooplankton Communities In Lake Mead, Nevada-Arizona, Usa, Patrick J. Sollberger, Larry J. Paulson

Publications (WR)

Zooplankton were collected from adjacent littoral and limnetic sites in Lake Mead, Nevada-Arizona, USA. Limnetic species dominated both littoral and limnetic zooplankton communities; littoral species rarely exceeded 2% of monthly total zooplankton densities. Low species richness of littoral taxa and high similarity in species composition between littoral and limnetic habitats appeared to result from uniform horizontal physical and chemical environments, due to horizontal mixing, and from the absence aquatic macrophytes. Significant differences in spatial distribution occurred in phytoplankton biomass, total zooplankton density, and fish "abundances; highest concentrations of these factors occurred nearest an inflow high in nutrients and progressively declined …


A Report On Black-Tailed Prairie Dogs In Nebraska, Their Biology, Behavior, Ecology, Management, And Responses To A Visual Barrier Fence, Nancy S. Foster Dec 1990

A Report On Black-Tailed Prairie Dogs In Nebraska, Their Biology, Behavior, Ecology, Management, And Responses To A Visual Barrier Fence, Nancy S. Foster

School of Natural Resources: Dissertations, Theses, and Student Research

I examined the effects of a visual barrier fence, which had a see-through visibility of 600/0, on the foraging, vigilance, and aggressive behaviors of adult female black-tailed prairie dogs from June through August 1990 in central Nebraska. I also examined changes in their home ranges and use of an area in response to this fence. Prairie dogs prefer an open view of their surroundings. Therefore, I expected animals near a visual barrier to spend more time in vigilance and aggression, and less time foraging. Adult female prairie dogs exposed to the visual barrier devoted more time to foraging and less …


Polymorphism Of Eimerian Oocysts Can Be A Problem In Naturally Infected Hosts: An Example From Subterranean Rodents In Bolivia, Scott Lyell Gardner, Donald W. Duszynski Dec 1990

Polymorphism Of Eimerian Oocysts Can Be A Problem In Naturally Infected Hosts: An Example From Subterranean Rodents In Bolivia, Scott Lyell Gardner, Donald W. Duszynski

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Since 1986, 364 tuco-tucos (Ctenomys spp.) representing 7 species were collected from 16 major collecting areas representing at least 4 distinct ecological habitats in Bolivia, South America. All were examined for coccidia, and 125 (34%) had oocysts in their feces including 84 of 236 (36%) Ctenomys boliviensis from tropical palm/savanna habitats; 1 of 3 (33%) C. conoveri from a chaco thorn forest; 3 of 7 (33%) C. frater from medium altitude grass habitats; and 6 of 8 (75%) C. lewisi and 31 of 35 (88%) C. opimus from high altitude/puna habitats. None of 3 C. …


Lake Mead Nutrient Enhancement Project, Peter D. Vaux, Larry J. Paulson, Nevada Department Of Wildlife, National Oceanic And Atmospheric Administration Dec 1990

Lake Mead Nutrient Enhancement Project, Peter D. Vaux, Larry J. Paulson, Nevada Department Of Wildlife, National Oceanic And Atmospheric Administration

Publications (WR)

The Lake Mead Fertilization Project is a research program designed to investigate the potential for using large-scale artificial fertilization to enhance the game fisheries of this reservoir through an increase in the population of threadfin shad, the system's primary forage species. A substantial decline in the population of largemouth bass, together with poor condition of adult striped bass, are the two major issues affecting the Lake Mead game fisheries. Both issues have been hypothesized to be a result of an inadequate amount of forage in the reservoir. Previous studies have in turn suggested that a major factor limiting the shad …


Freshwater Aquaculture In Western Australia., Fisheries Department Of Western Australia Sep 1990

Freshwater Aquaculture In Western Australia., Fisheries Department Of Western Australia

Fisheries Management Papers

Freshwater aquaculture in Western Australia is a relatively new industry. The first serious attempts began in 1975 after the Government relaxed the regulations on marron to allow for its farming and sale (at the legal minimum size of 17 mm carapace length). Since 1975, marron have been the focus of most attempts at aquaculture although in recent years trout, yabbies, freshwater aquarium fish and a number of other fish species have received greater attention. In 1984 the Minister for Fisheries established the Fish Farming Legislative Review Committee to review and make recommendations on the fish farming provisions of the Fisheries …


Future Policy For Charter Fishing Operations In Western Australia., P. Millington Sep 1990

Future Policy For Charter Fishing Operations In Western Australia., P. Millington

Fisheries Management Papers

About 40 boats in Western Australia gain some of their income from taking recreational fishing parties out on charter. Half of these charter boats are also licensed commercial fishing boats. There are few Fisheries Department controls over charter boat fishing at present. However, with increasing tourism and leisure time, there are sound reasons for the Minister for fisheries to tighten up the controls over charter boat fishing to prevent over-exploitation in some areas or on particular stocks.


Reproduction In The Hispid Cotton Rat, Sigmodon-Hispidus Say And Ord (Rodentia: Muridae), In Southeastern Virginia, Robert K. Rose, Michael H. Mitchell Jul 1990

Reproduction In The Hispid Cotton Rat, Sigmodon-Hispidus Say And Ord (Rodentia: Muridae), In Southeastern Virginia, Robert K. Rose, Michael H. Mitchell

Biological Sciences Faculty Publications

The hispid cotton rat, Sigmodon hispidus Say and Ord, a species of the southwestern United States that has been moving northward and eastward in this century, was first observed in Virginia in 1940. In this study of the cotton rat in southeastern Virginia, most males were reproductively competent from February through November, embryos were recorded from March through October, and litter sizes were comparable to those from other locations except Kansas. Also unlike the cotton rat in Kansas, animals grew at substantial rates during the winter in Virginia. The hispid cotton rat seems to have adjusted its breeding season in …


An Autecological Study Of Pyxidanthera Barbulata In The Blackwater Ecologic Preserve Virginia, John Marc Lowenthal Jul 1990

An Autecological Study Of Pyxidanthera Barbulata In The Blackwater Ecologic Preserve Virginia, John Marc Lowenthal

Biological Sciences Theses & Dissertations

Pyxidanthera barbulata (pyxie moss), a rare and endangered subshrub, has been found in decreasing numbers in it's "pine barren" habitat. An autecological study encompassing vegetation association analysis and environmental measurements was performed in the Blackwater Ecologic Preserve, its only known location in Virginia. The preserve is being subjected to controlled burning and the effect of burning on the species was evaluated. A multivariate analysis of variance was performed to identify species associations, and simple analysis of variance was done to find trends in the environmental data. Four taxa were positively associated with P. barbulata, Gaultheria procumbens, Vaccinium tenellum, Cladonia spp., …


Small Mammals In The Great Dismal Swamp Of Virginia And North Carolina, Robert K. Rose, Roger K. Everton, Jean F. Stankavich Jul 1990

Small Mammals In The Great Dismal Swamp Of Virginia And North Carolina, Robert K. Rose, Roger K. Everton, Jean F. Stankavich

Biological Sciences Faculty Publications

Small" mammals were surveyed in a range of habitats in the Great Dismal Swamp of Virginia and North Carolina. The survey is based on three chronologically overlapping studies, each lasting 15-18 months and for which the results have been reported separately. A different trapping method was used in each of the three studies: nest boxes, Fitch live traps, or pitfall traps. Only two species of mammals, both arboreal, were taken in nest boxes, compared with 10 and 9 species in Fitch live traps and pitfall traps, respectively. The Fitch live traps had a much higher catch rate per 1,000 trap-nights …


Description Of The Tadpoles Of Gastrophryne Pictiventris And Nelsonophryne Aterrima (Anura: Microhylidae), With A Review Of Morphological Variation In Free-Swimming Microhylid Larvae, Maureen A. Donnelly, Rafael O. De Sá, Craig Guyer Jun 1990

Description Of The Tadpoles Of Gastrophryne Pictiventris And Nelsonophryne Aterrima (Anura: Microhylidae), With A Review Of Morphological Variation In Free-Swimming Microhylid Larvae, Maureen A. Donnelly, Rafael O. De Sá, Craig Guyer

Biology Faculty Publications

The tadpoles of Gastrophryne pictiventris and Nelsonophryne aterrima are described based on material collected in Costa Rica and Panama, respectively. The tadpole of G. pictiventris resembles those of the other species of Gastrophryne. The tadpole of N. aterrima differs from other New World microhylid tadpoles in location of the vent tube (medial), the spiracular opening (ventral to the gut), and eyes (dorsolateral). The unique configuration of mouthparts in N. aterrima is described. Morphological variation in microhylid tadpoles is reviewed and six larval characters are analyzed cladistically for IO New World microhylid genera.


Fisheries Research Report No. 89 - Relationships Among Partial And Whole Lengths And Weights For Western Australian Pink Snapper Chrysophrys Auratus (Sparidae), M. J. Moran, C. Burton Jun 1990

Fisheries Research Report No. 89 - Relationships Among Partial And Whole Lengths And Weights For Western Australian Pink Snapper Chrysophrys Auratus (Sparidae), M. J. Moran, C. Burton

Fisheries Research Reports

Pink snapper, Chrysophrysauratus (Sparidae) is one of the major commercial and recreational fish in Western Australian inshore waters. This report presents a number of equations and conversion factors for management and scientific study of the species. Equations to calculate total lengths from partial lengths will facilitate enforcement of minimum legal lengths when snapper are landed in a "head-off" condition. For fisheries science purposes, there are equations to convert among total length, standard length and length to caudal fork; and to convert lengths and weights of processed fish to whole lengths and weights. Length-weight relationships are presented and compared with those …


The Prairie Naturalist Volume 22, No. 2. June 1990 Jun 1990

The Prairie Naturalist Volume 22, No. 2. June 1990

The Prairie Naturalist

Paul B. Kannowski, Editor

Nikki R. Seabloom, Assistant Editor

Douglas H. Johnson, Book Review Editor

CONTENTS

BREEDING BIOLOGY OF THE BLACK-TAILED PRAIRIE DOG IN NORTH DAKOTA ▪ R. W. Seabloom and P. W. Theisen

PATTERNS OF RESOURCE USE IN A LIZZARD COMMUNITY IN THE NEBRASKA SAND HILLS PRAIRIE ▪ R. E. Ballinger, S. M. Jones, and J. W. Nietfeldt

A THIRTEEN-YEAR SURVEY OF THE APHIDOPHAGOUS INSECTS OF ALFALFA ▪ N. C. Elliott and R. W. Kieckhefer

STATUS AND DISTRIBUTION OF PLAINS SHARP-TAILED GROUSE IN COLORADO ▪ A. W. Hoag and C. E. Braun

CHRISTMAS BIRD COUNTS FOR NORTH DAKOTA - …


Comparative Foraging Ecology Of Sheep And Goats In Caatinga Woodland In Northeastern Brazil, Scott L. Kronberg May 1990

Comparative Foraging Ecology Of Sheep And Goats In Caatinga Woodland In Northeastern Brazil, Scott L. Kronberg

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Small-ruminant production is an important part of the agricultural economy of northeastern Brazil. However, mild-to-severe undernutrition of livestock is an annual occurrence. Goats can tolerate the marginal forage conditions better than sheep, but the mechanisms underlying their superior tolerance are not understood.

An analysis of animal liveweights at the end of the year-long study indicated that reproducing mixed-race goats gained nearly twice (P<.05) the weight of reproducing hair-sheep of the Santa Ynez breed, and non-reproducing goats gained about 1.2 times more (P<.05) weight than non-reproducing sheep. Daily weight gains of lambs were less (P<.10) than those of kids for their first 80 days of life.

In the wet season, reproducing sheep and goats gained similar (P>.05) weight, while non-reproducing sheep gained more (P≤.05) than non-reproducing goats. Non-reproducing goats had greater (P<.05) forage organic matter intake (OMI) than the corresponding sheep in the two wet periods. In the late-wet period, non-reproducing goats had greater (P<.05) digestible energy intake (DEI) than corresponding sheep did but had similar (P>.05) digestible protein intake (DPI) as sheep.

In the dry …


Enhancement And Monitoring Of The Procambarus Clarkii Population In Lake Mead, Mikell Beth Hager May 1990

Enhancement And Monitoring Of The Procambarus Clarkii Population In Lake Mead, Mikell Beth Hager

Publications (WR)

Procambarus clarkii are found in extremely low numbers throughout Lake Mead, AZ-NV. The crayfish are an important dietary component for game fish. Enhancement of the crayfish population would broaden the fishery forage base. Crayfish were stocked and monitored in a study cove on Saddle Island to determine if the Procambarus clarkii population could be enhanced. A trapping survey of the area after the following reproductive season yielded low numbers of crayfish. A comparison of pre-stocking and post-stocking catch per trap day (CPTD) values revealed no significant increase in the population. Procambarus clarkii growth is limited by environmental factors in Lake …


The Effect Of Seasonal Cattle Grazing On California Bighorn Sheep Habitat Use, Melanie J. Steinkamp May 1990

The Effect Of Seasonal Cattle Grazing On California Bighorn Sheep Habitat Use, Melanie J. Steinkamp

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effect of seasonal cattle grazing on a newly reintroduced population of California bighorn sheep (Ovis canadensis californiana) in Big Cottonwood Canyon, Idaho, was studied. The hypothesis that bighorn sheep avoid cattle was tested. The issue of avoidance between bighorn sheep and livestock is arguable. Some studies have found that bighorn sheep avoid cattle while others have found no response of bighorn sheep to cattle.

Evidence was found to document the avoidance of cattle by bighorn sheep. The size of the bighorn's home range and core area decreased with the movement of cattle into areas of high bighorn …


A Descriptive Study Of Range Livestock Operations In The Somali Central Rangelands, Abdinasir M. Abdulle May 1990

A Descriptive Study Of Range Livestock Operations In The Somali Central Rangelands, Abdinasir M. Abdulle

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Information on livestock operations, particularly what kind of livestock operations are practiced in the Somali central rangelands, and how these operations differ for different herders in different vegetation types and farming systems, could serve as a major tool in making management decisions. This study provides a detailed description of range livestock operations in the Somali Central Rangelands. It also answers some important management questions.

Range livestock operations were inventoried through personal interviews with the owners and herders. Data are supplemented by previous nation-wide and regional survey statistics. Herd productivity data which include herd structures, age, age-related sales, slaughters, gifts, and …


The Effects Of Disease, Prey Fluctuation, And Clear-Cutting On American Marten In Newfoundland, Canada, Richard J. Fredrickson May 1990

The Effects Of Disease, Prey Fluctuation, And Clear-Cutting On American Marten In Newfoundland, Canada, Richard J. Fredrickson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Individual variation in survival and behavior of American marten (Martes americana) was studied in relation to disease, prey fluctuation, and clear-cutting from 10 January 1986 through 20 August 1987 in Newfoundland, Canada. Thirty-seven of forty marten captured on the study area were telemetered and monitored for part or all of the study.

Marten mortality was concentrated in two intervals, fall 1986 and late winter 1987. Mortality during fall 1986 was attributable to encephalitis, while marten deaths during late winter 1987 resulted from predation and starvation attributable to the prey decline. Nonsuppurative encephalitis was first detected 7 October 1986; …


Reproductive Ecology Of Wyoming Big Sagebrush (Artemisia Tridentata Ssp. Wyomingensis) : Effects Of Herbivory And Competition, Richard T. Decker May 1990

Reproductive Ecology Of Wyoming Big Sagebrush (Artemisia Tridentata Ssp. Wyomingensis) : Effects Of Herbivory And Competition, Richard T. Decker

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Herbivory and plant competition affect sexual reproduction of plants in various ways. Exclusion of mule deer (Odocoileus hemionus) and cattle, removal of plant competition (both inter- and intraspecific), and all combinations of the above treatments were used to examine the individual and combined affects on Artemisia tridentata ssp. wyomingensis (Wyoming big sagebrush) reproduction. Reproduction of Artemisia tridentata ssp. wyomingensis was divided into hierarchical levels of the number of: (1) modules per current-year ' s growth (CYG), (2) nodes per module, (3) inflorescence heads per node, (4) achenes per inflorescence head and (5) percent viable achenes. Counts at hierarchical …


Yellowstone's Northern Elk Herd: Critical Evaluation Of The "Natural Regulation" Paradigm., Charles Edward Kay May 1990

Yellowstone's Northern Elk Herd: Critical Evaluation Of The "Natural Regulation" Paradigm., Charles Edward Kay

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Prior to 1968, the National Park Service contended that an unnaturally large population of elk had severely damaged Yellowstone Park's northern winter range, including aspen and willow communities. However, under "natural regulation" management adopted in the earl y 1970s the agency now believes that vegetation changes in the park are due to normal plant succession, climatic change, or fire suppression, not ungulates. The agency also believes that large numbers of elk (12, 000 - 15, 000) have wintered on the park's northern range for the last several thousand years. This study tested several of the major assumptions or predictions of …