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Environmental Sciences

1987

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Articles 361 - 371 of 371

Full-Text Articles in Physical Sciences and Mathematics

Impact Of Grazing Systems On Rodent And Cottontail Rabbit Populations In South Texas, Meenakshi Nagendran Jan 1987

Impact Of Grazing Systems On Rodent And Cottontail Rabbit Populations In South Texas, Meenakshi Nagendran

Electronic Theses and Dissertations

Study sites were established at Rob and Bessie Welder Refuge and Encino Division of the King Ranch in south Texas to monitor the impact of Short-duration cell grazing (SDG) and Continuous grazing on small mammal and cottontail rabbit populations. Small mammals were live trapped (With occasional snap trapping) and cottontails were spotlighted. Vertical and horizontal components of vegetative structure were measured in terms of percent cover. There was paucity of rodents on the Welder Refuge – 8 captures for 9705 trap nights. In 1984 127 cottontails/km) and in 1985-1986 64 cottontails were seen along 436.8 km of road transects (.14 …

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First Year Growth And Survival Of Walleyes In Power Plant Evaporation And Holding Reservoirs, Michael P. Faler Jan 1987

First Year Growth And Survival Of Walleyes In Power Plant Evaporation And Holding Reservoirs, Michael P. Faler

Electronic Theses and Dissertations

Walleyes (Stizostedion vitreum) were stocked at a rate of 88 fish/hectare in two South Dakota power plant reservoirs and their growth and survival were monitored for one year. Length, weight, and survival of walleyes were significantly (P < 0.05) different between the two reservoirs. The walleyes attained a mean length of 230 mm (range 192 - 265 mm) in the Evaporation Reservoir and 205 mm (range 177-250 mm) in the Holding Reservoir. Mean weights attained by the fish were 104 g (range 65 - 165 g) in the Evaporation Reservoir and 89 g (range 48 - 135 g) in the Holding Reservoir. The growth rates of walleyes in the two reservoirs were inversely related to survival and standing crops. Walleye survival in the Evaporation Reservoir was 1.5% (0.95 C.L., 0.9 - 2.8%) with a standing crop of 0.13 kg/hectare, whereas survival in the Holding Reservoir was 17.2% (0.95 c,L., 13.5 - 22.9%) with a standing crop of 1.33 kg/ hectare. Walleye standing crop estimates, calculated in terms of weight of fish per volume of water beneath the ice, -were similar in the two reservoirs1 standing crops were 0.06 kg/1000 m3 in the Evaporation Reservoir, and 0.08 kg/1000 m3 in the Holding Reservoir. Estimated forage fish standing crops were 1 .21 kg/hectare in the Evaporation Reservoir and 1.91 kg/hectare in the Holding Reservoir.

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Impacts Of Stocking Herbivorous Fishes For Aquatic Macophyte Removal Upon South Dakota Ponds, John Christopher Young Jan 1987

Impacts Of Stocking Herbivorous Fishes For Aquatic Macophyte Removal Upon South Dakota Ponds, John Christopher Young

Electronic Theses and Dissertations

Aquatic macrophyte removal by herbivorous fishes was investigated to determine changes in the predator-prey relationship of largemouth bass, Micropterus salmoides, and bluegills, Lepomis macrochirus, stocked into 15 prairie ponds. Monosex grass carp, Ctenopharyngodon idella, and hybrid grass carp, Ctenopharyngodon idella x Hypophthalmicthys nobilis, were each stocked at a rate of 247 fish/hectare into five study ponds. Largemouth bass and bluegills were each stocked into 12 study ponds at 247 fish/hectare in July, and 1235 fish/hectare in September, 1984, respectively. Additional largemouth bass were stocked at a rate of 247 fish/hectare into nine study ponds in July, 1985. Conductivity was the …

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Habitat Use By Beaver Along The Big Sioux River, Charles D. Dieter Jan 1987

Habitat Use By Beaver Along The Big Sioux River, Charles D. Dieter

Electronic Theses and Dissertations

Habitat utilization and lodge site selection by beaver (Castor canadensis) were investigated during 1985 and 1986 along the Big Sioux River in eastern South Dakota. Because livestock grazing has affected the number and size of trees available for beaver use, the study area was portioned into grazed, ungrazed, and farmed habitat. Diameter at breast height (DBH) of trees in grazed areas was greater (p < 0.01) than in ungrazed or farmed areas. Almost half (48%) of the trees in ungrazed areas were small (DBH < 7.5 cm), while a majority (58%) of the trees in grazed areas had large diameters (DBH > 30 cm). Beaver activity was evident on 286 of 2410 (11.8%) trees (DBH > 2.5 cm) and 756 of 7,794 (9.7%) stems (DBH < 2.5cm) sampled. A greater proportion (p < 0.01) of trees were cut by beavers in ungrazed than in grazed areas. Beaver did not select tree species for cutting according to availability (p < 0.01). Green ash (Fraxinus pennsylvanica) was selected for cutting while both boxelder (Acer negundo) and hawthorn (Crataegus mollis) were selected against. Sandbar willow (Salix exigua) stems were important for food and building materials. Trees cut by beaver were significantly smaller in diameter (p < 0.01) than uncut trees. Mean distance from water of cut trees was also less (p < 0.01) than for uncut trees. Over half (52%) of the trees damaged by beaver were not killed and either resprouted or remained alive and standing. Of 8 variables examined at lodge sites, analysis indicated that the 2 most important factors in beaver lodge site selection were riverbank slope and horizontal cover density between 0.9 m and 1.8 m above ground (read from 10 m). Mean slope of the riverbank at lodge sites (40.7 degrees) was greater (p < 0.01) than at control sites (26.7 degrees), while mean horizontal cover density between 0.9 m and 1.8 m (read from 10 m) was also greater (p < 0.01) at lodge sites (53%) than at control sites (28%). Ungrazed habitat was selected by beaver for lodge sites, and grazed areas were selected against. Although 40% of the study area was ungrazed, 27 of 33 (82%) active lodges were located in these areas. Ungrazed areas along the Big Sioux River are important for beaver populations and selection for these areas by beaver reflects habitat quality.

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Forest Conservation In Nepal: Encouraging Women's Participation, Augusta Molnar Jan 1987

Forest Conservation In Nepal: Encouraging Women's Participation, Augusta Molnar

Poverty, Gender, and Youth

This issue of SEEDS focuses on ways in which women have been involved in a government forest conservation and restoration program in Nepal. As is common with many large-scale projects with a general impact, women were not a direct focus of the project's original design. As activities got underway, however, both the Nepali staff and their expatriate colleagues quickly realized that the direct involvement of women was crucial to the success of the project's participatory strategy. Over the initial five years, 1980 to 1985, a number of approaches to addressing women's needs and generating their active participation were tried. The …

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Interaction Of Long Waves And Nearshore Barred Topography--A Mechanism Of Bar Migration, Chang-Shik Kim Jan 1987

Interaction Of Long Waves And Nearshore Barred Topography--A Mechanism Of Bar Migration, Chang-Shik Kim

Dissertations, Theses, and Masters Projects

It has been widely observed in nature that longshore bar topography changes profile in the onshore-offshore direction. It is common for some bars to migrate onshore during post-storm phases and offshore during storms. Although the behavior of submarine bars has been widely reported, its mechanisms and forcings are far less clear. to determine the mechanism for bar migration or for the persistence of bar systems, a numerical model is developed, which accounts for the mass transport velocities in the bottom boundary layer induced by a family of combined long waves at surf-beat frequencies and wind waves. The present approach simulates …

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An Assessment And Comparison Of Hazardous Waste Management Hessen, Frg And Ontario, Canada, Elaine F. Collis Jan 1987

An Assessment And Comparison Of Hazardous Waste Management Hessen, Frg And Ontario, Canada, Elaine F. Collis

Theses and Dissertations (Comprehensive)

Hazardous waste management has recently become an issue of great concern for governments in industrialized countries. In spite of this, no one country has established a successful framework which guarantees the safe handling and disposal of hazardous wastes. The ideal system would generate no hazardous wastes in the first place but this, of course, is wishful thinking for highly industrialized societies. The next best or “preferred” solution is a system which emphasized reduction and recycling of hazardous wastes. The existing waste management systems in the world today, however, almost exclusively emphasize treatment and disposal. This thesis assesses the hazardous waste …

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The Incorporation Of Environmental Perception Information Into Wilderness Park Safety Planning, Thomas Craig Waldichuk Jan 1987

The Incorporation Of Environmental Perception Information Into Wilderness Park Safety Planning, Thomas Craig Waldichuk

Theses and Dissertations (Comprehensive)

The park safety planning process currently in use limits users’ inputs to accident statistics. It would be better to more accurately anticipate accident-prone locations and to take preventative measures. A planning methodology is proposed which integrates the safety perceptions of park users into the decision-making for locating facilities and services: the Recreation Opportunity Spectrum (ROS) serves as a systematic planning guide for such decision-making and is compatible with park policy and objectives. Applications to Garibaldi Provincial Park, British Columbia, and statistical and cartographic analyses of 273 questionnaires returned from there, indicate that park users’ perceptions can be advantageously incorporated into …

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Consumption Of Water By Livestock, G J. Luke Jan 1987

Consumption Of Water By Livestock, G J. Luke

Resource management technical reports

No abstract provided.

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Storage Life Of Farm Dams, G J. Luke, C G. Denby Jan 1987

Storage Life Of Farm Dams, G J. Luke, C G. Denby

Resource management technical reports

No abstract provided.

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The Land Resources And Carrying Capacity Of Gascoyne Locations 228 And 229, North Of Carnarvon, Western Australia, M R. Wells, Veronica P M Oma, Alexander Mcrae Holm Jan 1987

The Land Resources And Carrying Capacity Of Gascoyne Locations 228 And 229, North Of Carnarvon, Western Australia, M R. Wells, Veronica P M Oma, Alexander Mcrae Holm

Resource management technical reports

No abstract provided.

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