Department of Fish, Wildlife, and Conservation Biology

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https://hdl.handle.net/10217/100423

These digital collections include theses, dissertations, faculty publications, student publications, and datasets from the Department of Fish, Wildlife, and Conservation Biology. Due to departmental name changes, materials from the following historical departments are also included here: Fishery; Fishery and Wildlife Biology; Wildlife Biology.

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Open Access
Comparative winter nutrition of elk in the Jemez Mountains, New Mexico
(Colorado State University. Libraries, 1981) Rowland, Mary M., author; Alldrege, A. William, advisor; White, Gary C., committee member; Bailey, J. A., committee member
Diet quality and nutritional status of elk {Cervus elaphus nelsoni) were studied in the Jemez Mountains, New Mexico, during January-April 1980. A recently burned montane area, including portions of Bandelier National Monument, and an unburned upper montane area in the Valle San Antonio were selected for winter range comparisons. Botanical composition of elk diets, determined by microhistological analysis of feces, was markedly different between the 2 areas, passes dominated diets in the burned area (x =90%), but were consumed in nearly equal proportions with browse in the unburned area (x = 52%, grasses; x = 41%, browse). Forbs were minor dietary components in both areas. Diet botanical com-position did not vary during the winter and early spring. Grasses were more digestible than was browse, but crude protein content was similar between forage classes. Temporal increases in quality of grasses were significant, whereas browse forages remained relatively constant in quality. Comparisons of forage protein and IVDOM (in vitro digestible organic matter) revealed no differences between locations. Dietary protein ranged from 3.5-7.2% in Bandelier and from 4.7-7.5% in the Valle San Antonio, and was consistently superior in the unburned area. Increases in diet IVDOM in Bandelier (35% to 48%) surpassed those in the Valle San Antonio (33% to 39%) and were more rapid in Bandelier. Increases in diet quality were highly correlated with changes in quality of grasses consumed by elk. Observed disparities in diet quality between areas were caused primarily by differences in diet compositions and the differing qualities of grasses vs. browse. Forage quality was more variable than was diet quality, indicating the ability of elk to maintain relatively constant diet quality when confronted with large fluctuations in forage quality. A simulation model of ruminant energy and nitrogen balance was used to predict potential effects of diet quality on elk nutritional status. Greater energy deficits were predicted for elk in the unburned area, effecting greater losses of fat and lean body. Superior dietary nitrogen in the unburned area was insufficient to compensate for these losses.
Open Access
Sage grouse movements and habitat selection in North Park, Colorado
(Colorado State University. Libraries, 1982) Schoenberg, Thomas John, author; Ryder, Ronald A., advisor; Braun, Clait E., advisor; Hein, Dale A., committee member; Walter, Richard G., committee member
Sage grouse (Centrocercus urophasianus) movements and habitat selection were studied in North Park, Colorado during April-August 1979 and February-August 1980. Sixteen male (12 adults, 4 juveniles) and 22 female (13 adults, 9 juveniles) sage grouse were captured and fitted with radio transmitters. Mortality of radio-marked sage grouse during the monitoring period was low (13%). Raptors were the most important predators. Twenty-two of 36 (61%) transmitters were recovered after use on sage grouse. Wildlife Materials transmitters had longer (P< 0.05) average life (209 days) than AVM transmitters (136 days). Sage grouse used 2 major wintering areas in the northeast and southeast quadrats of North Park in 1980. Preferred winter habitat encompassed only 3. 7% of the sagebrush (Artemisia spp.) – dominated land in North Park. There was no difference (P > 0.05) between sexes in average daily winter movements or size of winter range areas. Daily movements averaged 1.6 and 1.5 km for males and females, respectively. Winter flock break-up and dispersal to breeding areas began during the 2nd week of April coincident with the onset of the spring thaw. Movements of 3 radio-marked males from the wintering area to leks averaged 27.5 km. Four hens traveled an average of 29.9 km from the wintering area to nests. Daily movements of males from leks to feeding-loafing (FL) sites averaged 0.9 km. Dispersal direction from Raven Lek to FL sites was nonrandom (P < 0.001). Average distance that hens traveled from leks to nest sites was 2.7 km. Adult hens traveled farther (P < 0.05) than juvenile hens. Pre-incubation movements from nests to FL sites averaged 0. 4 km. Movements of both sexes from breeding areas and nests to meadows along the Michigan and Canadian rivers occurred throughout June, primarily during the latter half of the month. Four of 5 radio-marked males and 5 of 6 radio-marked hens moved to the meadow nearest the lek attended or nest site, respectively. Summer movements were restricted to relatively small areas along the Michigan and Canadian rivers. Few differences in slope and aspect were observed between habitats selected by sage grouse and random sites. Greater differences in habitat selection were seen when topographic features were examined. Sage grouse winter FL sites were primarily in sagebrush-dominated draws and on windswept ridges whereas breeding season FL sites were predominantly on 0-5 and 6-10% open slopes. Hens with broods preferred draws with little sagebrush and high forb and grass cover. Sage grouse selected winter FL habitats with better (P ≤ 0.05) structural cover (sagebrush clump size, plant dimensions, canopy cover) than breeding season FL sites. Structural characteristics of nest sites, however, were more similar to winter FL sites. Only leks had poorer (P < 0.05) structural cover than random sites. Except for FL sites of males during the breeding season, sage grouse chose sagebrush with higher (P < 0. 05) percent foliation (75-78 %) than found at random sites (65%). Males, hens with broods, and unsuccessful hens chose summer meadow habitats with similar (P > 0. 05) forb and grass cover and grass height. Males selected breeding season FL sites with higher (P < 0. 05) soil organic matter content than did hens or that found at random sites. The higher organic matter content was attributed to 2, 4-D spraying of the area around Raven Lek in 1963 and subsequent decomposition of sagebrush plants. Discriminant function and principal components analyses were also used to investigate sage grouse habitat selection. Three discriminant functions explained 93. 6% of the total sample variance whereas 5 principal components explained 94. 1% of the sample variance. In both analyses, sagebrush plant size was the most important habitat factor separating different types of sage grouse use and random sites. Degree of microhabitat selection was the 2nd most important factor followed by sagebrush clump size and canopy cover. These analyses revealed differences in habitats selected by sage grouse between and within seasons as well as habitat differences between random and sage grouse use sites.
Open Access
The effect of depth-velocity correlations on aquatic physical habitat usability estimates
(Colorado State University. Libraries, 1982) Prewitt, Charles G., author; Carlson, Clarence A., committee member; Stalnaker, Clair B., committee member
Recent developments in instream flow evaluations have resulted in a variety of assessment methodologies. Of these, the Instream Flow Incremental Methodology permitted consideration of both physical habitat parameters (e.g., depth, velocity, substrate and temperature) and preferences for certain values of these parameters by selected organisms. This methodology was based on the PHABSIM (Physical HABitat SIMulation) computer system, which allowed 1) prediction of depths, velocities and associated substrates at a stream reach; 2) determination of weighting factors for the predicted values from preference curves constructed for each organism or group of organisms; and 31 application of a joint weighting factor (obtained by multiplying the individual weighting factors) to the surface area of the stream reach to obtain weighted usable area (WUA) for that reach. WUA is an indicator of the extent of available preferred physical habitat and a valuable tool in streamflow assessments. Calculation of joint preference factors by multiplication was statistically permissible only if the variables were uncorrelated. Using the original calculation approach, variable correlations were assumed to be zero, but might actually be quite high. To test the hypothesis that two variable (depth-velocity) correlations greater than zero did not significantly affect WUA results, a study was designed to account for effects of increased levels of correlation upon WUA calculated using various preference curves in a variety of stream types and channel characteristics. In the entire data set, the hypothesis was supported only to a correlation level of .2, a level unlikely to occur. However, results were more consistent in medium and large streams than in small streams. Further, in medium and large streams with complex channel configuration, users could expect independent depth-velocity curves to give results similar to correlated curves even if the actual correlation level was 0.4 or in many cases 0.6. Indicators of simple and complex channel conditions and discharge ranges of small, medium and large streams were given. Ecological (niche and guild theory) inferences related to habitat requirements and impact analysis were briefly discussed, and hypotheses regarding habitat diversity and stability presented. Definition of a fundamental niche using a multivariate statistical approach was suggested as a tool in predicting effects of environmental changes upon usable habitat.
Open Access
Wildlife values and management in northern Sudan
(Colorado State University. Libraries, 1983) Nimir, Mutasim Bashir, author; Nagy, Julius G., advisor; Young, Robert A. (Robert Alton), 1931-2013, committee member; Decker, Eugene, committee member; Alldredge, A. William, committee member
An overview of wildlife resources and wildlife values and management are presented in this study. Information on history of wildlife distribution, wildlife values and management practices have been obtained from writings of early travelers and explorers and government archives. Information on present status of wildlife has come from surveys conducted by the author and other workers during the last 15 years. The Wildlife Administration records were reviewed for information on laws, policies, and records of game license sales and export of wildlife products. The province of Southern Darfur was chosen to develop a case study and to make conclusions which could be applied elsewhere in Northern Sudan. Wildlife has been more abundant in Northern Sudan in the past than it is today. Information on present distribution and abundance of wildlife is very limited. The conservation status in national parks, game reserves and sanctuaries is rated as unsatisfactory. Factors causing losses of wildlife resources are inadequate laws, loss of habitats, lack of qualified personnel, lack of public awareness about wildlife conservation and conflicts in land use planning. Economic values of wildlife are of central importance to the future of wildlife conservation in Northern Sudan. The present economic values of wildlife are related to hunting, trade in wildlife products and wildlife damage to agriculture and livestock. Legal hunting is of limited significance as possession of firearms is restricted by law and wildlife areas are remote from where the majority of the population live. Ivory and reptile skin trade provide considerable revenue. As most of the wildlife products are collected through illegal hunting and traded illegally the economic benefit from wildlife is not appreciated by the government. Wildlife damage to agriculture and livestock is most serious in Southern Darfur where it is mostly caused by baboons and hyenas. Recommendations include that surveys should be conducted to present realistic estimates of wildlife distribution and abundance. Realistic conservation goals should be adopted based on surveys' results. Wildlife conservation should be incorporated in national land use plans. The Wildlife Administration should recruit biologists and relocate its personnel and vehicles closer to wildlife areas. Wildlife programs should be coordinated in Northern and Southern Sudan. New laws should be adopted. The trade in ivory and other wildlife products should be controlled. The Wildlife Administration should monopolize all ivory export and taxes should be increased in export of wildlife products. The Wildlife Administration should be more involved in controlling wildlife damage. Laws should be changed to allow the Wildlife Administration to direct revenue generated from wildlife towards wildlife conservation projects. It is recommended that education in wildlife conservation should be included in school programs and in the Sudanese media.
Open Access
Ecology of desert bighorn sheep in Colorado
(Colorado State University. Libraries, 1986) Creeden, Paul J., author; Cook, Robert S., advisor; Bailey, James A., committee member; Ellenberger, John H., committee member; Lehner, Philip N., committee member
Desert bighorn sheep (Ovis canadensis nelsoni & mexicana) were transplanted into western Colorado in 1979, 1980 and 1981. The ecology of these sheep following transplanting was studied during 1982 and 1983. The population increased 18%, from 34 to 40 sheep, during this period. Minimum natality rates of 71% and 75% were observed. Survival of lambs born in 1982 to 1 year of age was at least 70%. Three of 4 suspected lamb losses occurred during the fall and winter months. Five adult mortalities were recorded. Two of these were predator related and occurred within the first few months of transplanting. Timing of reproductive activities was significantly delayed during the first year following transplanting. Ewes bred in Arizona and transplanted to Colorado in 1981 lambed significantly earlier in 1982 than they did in 1983 after breeding in Colorado. During 1982, ewes from the 1979 and 1980 transplants lambed significantly later than the ewes released in 1981. No significant differences in reproductive seasons were evident between transplant groups during 1983. Ewes preferred inner-canyon habitats for lambing. They most often selected ledges at the bases of sheer canyon walls and above steep talus slopes. All sites were located on escape terrain. A moderate degree of fidelity of ewes to lambing sites used in previous years was observed. The seclusion period of ewes during the lambing season varied with the social status of individual ewes. Dominant females remained alone for less time, both before and after parturition, than did subordinate females. Movements of ewes with lambs following parturition varied with the ewe's home range size. Long-distance moves were first recorded with 2-week old lambs. Dispersal of sheep following transplanting appeared to be influenced by winter weather conditions and by association with other bighorn. Both factors seemed to decrease movements. Dispersal patterns exhibited immediately following release influenced ultimate home range size. Sheep released in 1981 centered activities around the areas explored initially following transplanting. Overlapping home ranges were observed for both rams and ewes, p ranging in size from 4.6 to 44.7 km2. Home range sizes of ewes varied significantly among release groups and with habitat-use patterns. Coefficients of association were generally low in the herd. Bighorn ewes associated in direct proportion with the amount of range shared. Bighorn use of aspect differed between the winter-spring and summer periods. Use of inner-canyon habitats appeared to be related to canopy coverage of trees and shrubs.
Open Access
Sharp-tailed grouse response to lek disturbance in the Carberry Sand Hills of Manitoba
(Colorado State University. Libraries, 1986) Baydack, Richard Kenith, author; Hein, Dale, advisor; Braun, Clait E., committee member; Baker, Myron Charles, 1939-, committee member; Bailey, James A., 1934-, committee member; Ryder, Ronald A., committee member
Characteristics of sharp-tailed grouse (Tympanuchus phasianellus) leks, response of grouse to experimental disturbances of leks, and use of replacement leks were studied in the Carberry Sand Hills, southwestern Manitoba, from May 1983 through June 1985. Ten active leks were located an average of 2.2 km apart and were generally oval-shaped, with a NW to SE orientation. Leks averaged 450 m2. Leks were higher than most surrounding terrain, and sloped ≤l% over display areas. Vegetation height was less on display than on perimeter areas. Cover consisted of grass (68%), forbs (15%), bare ground (15%), and shrubs (1%). Visibility on display areas increased progressively from summer to fall to spring. Each lek had escape cover ≤500 m and trees used for perching ≤400 m from lek center. Response of sharp-tailed grouse to lek disturbance varied between sexes. Male sharptails were tolerant of all experimental lek disturbances except visible human presence. They continued to display in spite of parked vehicles, snow fencing, propane 'bangers', scarecrows, radio sounds, and leashed dogs. Males displaced due to human presence generally remained in prairie habitat within 400 m of the traditional lek. They often returned to the lek within 5 minutes of cessation of disturbance. Displaced male grouse spent most of their time (70%) 'sitting motionless' during disturbance. Female sharptails were displaced from leks by all tested disturbances but were not monitored. Replacement leks attracted some displaced male sharp-tailed grouse. Successful replacement leks resembled traditional leks at test distances of 200 or 400 m. Male decoys, female decoys in precopulatory position, and tape-recorded grouse vocalizations were necessary to induce males to attend replacement leks. Some replacement leks were used daily by males during disturbance, but use was limited to <40% of total disturbance time. Males attended replacement leks more often during morning than evening display periods. Activity of males on replacement leks was dominated by 'sitting motionless', although some displaying occurred. Female sharptails were rarely observed at replacement leks, but when present their attendance incited male display activity.
Open Access
Utilization of wildlife resources in Nigeria
(Colorado State University. Libraries, 1987) Adeola, Moses Olanrewaju, author; Nagy, Julius G., advisor; Decker, Eugene, committee member; Eckert, Jerry, committee member; Cringan, Alexander T., committee member; Mahoney, Charles L., committee member
Primary purposes of this study were to determine: which wildlife species are being used by the people, in what quantity, and during what season; the effect of religion, culture, and tribal festivals on game species utilized; the game species utilized or consumed in different ecological zones; which game species and parts of wild animals are used for healing and preventive medicine in each ecological zone; and to assess the economic and recreational values of the utilized wildlife. The three ecological zones surveyed for consumptive uses of wildlife resources in Nigeria were: savanna (Bauchi, Plateau, Niger, and Kwara states), deciduous (Anambra and Bendel states), and rain forest (Oyo and Cross River states). For nonconsumptive uses, three national parks (Kainji Lake National Park, Yankari Game Reserve, and Jos Wildlife Park) and four zoological gardens (Ibadan, Jos, Enugun, and Ogba) were surveyed. Data were collected from farmers, hunters, and visitors in each of the conservation areas through a person-to-person questionnaire interview. This study confirmed that small game were the most abundant wild animals in the three zones surveyed and most of them were located in the savanna region. This study indicates that a major proportion of animal protein consumed by farmers and hunters in the regions came from wild animals. Farmers and hunters in the savanna preferred using small game (rodents) and big game (duikers) more than in the other zones. Wildlife species were used more during installation ceremonies (of a new chief, Emir, Oba, and Obis) than in other cultural festivals. In the rain forest more species were used for installation ceremonies than in any region surveyed. During Muslim festivals in Nigeria, farmers rarely used wildlife species, but some were used to supplement income. Christians used many different wild animals for religious festivals, but more were used during the Easter period in the deciduous region than the rain forest and savanna regions. Expenditures per visitor in the three national parks showed more per capita expenditures from foreigners than Nigerians. The number of nights stayed in the national parks and game reserves is the major factor in determining how much money the visitor spent.
Open Access
Elk migration, habitat use and dispersal in the Upper Eagle Valley, Colorado: summary report 1986-1988
(Colorado State University. Libraries, 1989) de Vergie, William J., author; Alldredge, A. William, author
Open Access
The bighorn sheep of Battlement Mesa - a low elevation population
(Colorado State University. Libraries, 1991) Cunningham, Mary Louise, author; Bailey, James A., advisor; Alldredge, A. William, committee member; Lehner, Philip N., committee member
I studied bighorn sheep on Battlement Mesa, Colorado, from 12/88 to 7/90, to determine present and past herd status and distribution, so that 1) management options are clarified and 2) future management activities may be evaluated. I studied the herd by tracking 1 radio-collared ewe and obtaining visual observations and by systematically sampling study area units for sheep, sheep sign, potential competitors, potential predators and sheep carcasses. I recorded water sources that were encountered. I developed an historic perspective of the herd by searching agency files and local newspapers and interviewing local residents. The herd numbered up to 200-250 animals in the early 1900s and declined to an estimated 50 animals by 1970. Minimum herd sizes during 1989 and 1990 were 23 and 26, including lambs, respectively. Since 1961, the herd has abandoned approximately 56 km2 of historic range in the Mamm Peaks area. The herd decline corresponded with probable vegetation changes on Battlement Mesa, intensive livestock grazing through the 1950s, reports of poaching and an increasing elk herd. Sheep remained on the western portion of the range during winter and spring, 1989. Ewe/juvenile groups migrated to Anderson and Durant Gulches between 5/15-7/15/89 for lambing. Rams were more dispersed and in groups of 1-3, except during the rutting season. Ewe/juvenile group size ranged from 1-13. During dry months, (7/89, 8/89, 6/90) sheep concentrated in Anderson and Durant Gulches where a free-flowing spring and a seep were located. Bighorn sheep on Battlement Mesa appear limited by dense mountain shrub stands which separate all productive meadows from escape terrain and cover historic migration routes. A significantly greater use of the shale slope habitat contributed most to rejecting the null hypothesis that sheep use habitat types in proportion to their availabilities on Battlement Mesa. Sheep remained on shale slopes most (75% of all observations) of the time, using scattered grasses, forbs and shrubs for forage and seeps for water. Intensive and long term habitat management for bighorn sheep on Battlement Mesa is required. I suggest a 4-phase management program to improve existing range and later to reestablish and maintain historic migration corridors to productive historic summer range. Without management to improve existing conditions, this small, unique herd will remain static or decline.
Open Access
Summary progress report on the Upper Eagle Valley elk study: the effects of ski area expansion on elk, accuracy of 2 telemetry systems in mountainous terrain, summer data - 1991
(Colorado State University. Libraries, 1992) Morrison, James R., author; Alldredge, A. William, author
Open Access
Mule deer movements, survival, and use of contaminated areas at Rocky Flats, Colorado
(Colorado State University. Libraries, 1992) Symonds, Kate K., author; Alldredge, William A., advisor; Swift, David M. (David Munson), committee member; White, Gary C., committee member
Rocky Mountain mule deer (Odocoileus hemionus hemionus) reside on plutonium contaminated land that surrounds the Rocky Flats Nuclear Weapons Facility, Colorado. Concern exists over the potential for deer to transport radionuclides away from Rocky Flats. Deer may potentially transport radionuclides through excretion of contaminated forage and soil away from the ingestion site, or by retention of radionuclides in tissues or the hide. To assess their potential to transport radionulcides and to determine annual movement patterns, deer were radio-located throughout the year. Rocky Flats deer were year-round residents, seldom moved farther than 0.05 km from the buffer zone boundaries. At least 9 male yearlings left Rocky Flats, and yearlings are, therefore, the most likely age class for radionuclide transport. Based on annual movement patterns I observed, the potential for does and fawns to transport radionuclides off-site appears to be very low, although more data are needed to better assess movement patterns of yearlings. Two areas in the buffer zone contain detectable levels of radionuclides and are accessible to deer. I compared deer use to availability in these areas during winter and summer 1991. During winter, 45.3% and 52.0% of radio-collared does and fawns showed preference (P ≤ 0.027) for these 2 areas over non-contaminated areas. During summer, 39.0% and 36.7% of deer preferred (P ≤ 0.027) each area to non-contaminated areas. I also collected tissue samples from 7 vehicle-killed deer that were known to inhabit the buffer zone and submitted them for radionuclide analysis. All tissues had plutonium activities below detection limits. Again, transport of radionuclides appears to be very low, but because of small sample size, any conclusion regarding plutonium transport is premature. The deer population size was estimated from a helicopter survey during summer 1990, and from a ground survey during winter 1991. Population estimates were 161 (95% confidence interval 136-220) during summer, and 199 (95% confidence interval 198-207) during winter. Winter 1991 buck:doe ratio was 35:100, and fawn:doe ratio was 90:100. Annual adult doe survival rates were 0.792 ± 0.083 (SE) in 1990 (n = 24), and 0.857 ± 0.059 (SE) in 1991 (n = 35), and were not statistically different (P = 0.19). Winter survival rate for female fawns was 0.895 ± 0.043 (SE) (n=19), and male fawn survival rate for the same time period was 0.950 ± 0.046 (SE) (n=21), and did not differ statistically (P = 0.51). The major cause of mortality among radio-collared deer was collisions with vehicles (47.8%), and predation (21.8%). Accidents and unknown causes comprised the remainder of mortalities (30.4%).
Open Access
Influence of abiotic and biotic factors on the response of benthic macroinvertebrates to metals
(Colorado State University. Libraries, 1995) Kiffney, Peter Michael, author; Clements, Will, advisor; Fausch, Kurt D., committee member; Kondratieff, Boris C., committee member; Chapman, Phillip, committee member
Stream ecologists are well aware that chemical, biological, and physical characteristics of lotic systems vary spatially and temporally. With this in mind, I designed a series of experiments and field studies to examine the role of spatial variation in stream benthic macroinvertebrate communities in response to metals. Specifically, I tested the hypothesis that stream invertebrate communities from pristine streams of different size and altitude varied in their response to metals. To evaluate how metals affected biotic interactions, I manipulated invertebrate density, predation intensity, and metals in stream microcosms. Using stream invertebrate communities, I also designed an experiment and field survey to identify reliable bioindicators of metal contamination in western streams. Results from microcosm experiments and field studies showed that benthic invertebrate populations from high-altitude streams were more sensitive to the effects of metals than invertebrate populations from low-altitude streams. For example, Baetis sp. and Rhithrogena hageni from Little Beaver Creek (LBC), Colorado, (high-altitude stream) were significantly more sensitive to zinc than the same species from the South Fork of the Poudre River (SFP) (low-altitude stream) in stream microcosms. Results from field surveys showed that densities of most groups of aquatic insects (e.g., Ephemeroptera, Plecoptera, Trichoptera) were lower at high-altitude metal contaminated streams than those same groups at low-altitude streams. Other factors, such as variation in water temperature or nutrient concentrations between high- and low-altitude streams, could be lll responsible for these differences. However, because invertebrate responses were similar under controlled and field conditions, I hypothesize that differences in abundances between reference and contaminated locations was a result of metals. To determine if body size contributed to the variation in sensitivity of insects to metals, size measurements were made on species collected from LBC (high-altitude) and SFP (low-altitude). Measurements were also made on species from control and metal-treated stream microcosm. Most species were smaller at LBC (high-altitude stream) than the same species from SFP (low-altitude stream). For example, the mayfly Baetis tricaudatus and the caddisfly Arctopsyche grandis were significantly larger at SFP than LBC. In addition, insect body size was larger in metal-dosed microcosms than in controls. Brachycentrus sp., B. tricaudatus, R. hageni, Eohemerella infrequens, and P. badia were significantly larger in metal-treated microcosms than in controls. Logistic regression indicated survival in metal-dosed microcosms was less for small individuals than for larger individuals of the same species. These results suggest that some insect species from high-altitude streams were smaller than those from low-altitude streams, and that survival was greater for larger lifestages. Thus the variation in response of macroinvertebrates between different altitude streams observed in earlier studies may be due to differences in body size. The effects of low levels of metals (half the chronic levels of Cd, Cu, and Zn) on some species varied in relation to invertebrate density (low and high density) and invertebrate predation (no predators added and predators added). The abundance of Hydropsyche sp. was significantly lower in metal-dosed, high density treatments than in control, high density treatments. Moreover, the effects of an invertebrate predator (Hesperoperla pacifica) on Hydropsyche sp. was significantly greater in metal-dosed microcosms than in controls. These results suggest that metals interact with biotic factors to influence stream invertebrate community structure, and that effects occurred at metal concentrations lower than chronic criteria value. Toxicity experiments in stream microcosms showed that the abundance and species richness of aquatic insects were significantly reduced at 1x, 5x and 10x the United States Environmental Protection Agency chronic levels of cadmium, copper, and zinc (1x=1.1, 5.0, and 110 μg/L Cd, Cu, and Zn, respectively). Mayflies were the most sensitive group, as the abundance of Baetis sp. and Rithrogena hageni were significantly reduced in the Ix treatment. The response of Drunella grandis was size dependent, as small lifestages were significantly more sensitive than large lifestages. Stoneflies were also affected, but their response was more variable with abundances of some species (Pteronarcella badia) being reduced in the Ix treatment, whereas other species were unaffected (Sweltsa sp.). Heptageniid mayflies were consistently less abundant downstream of sources of metal contamination in the Arkansas and Eagle rivers, whereas the response of other measures were more variable. For instance, species richness and total density were greater at a metal-contaminated site on the Arkansas River compared with an upstream reference site. Therefore, results from this experiment and field survey suggest that changes in abundance of heptageniid mayflies may provide a reliable indicator of metal-contamination in western streams.
Open Access
Ecological effects of reservoir operations on Blue Mesa Reservoir
(Colorado State University. Libraries, 1996) Johnson, Brett M., author; Wise, Michael J., author; Herwig, Brian, author; Szerlong, Glenn, author; Faber, Derrek, author; Byall, Blake, author; Department of Fishery and Wildlife Biology, Colorado State University, publisher
Annual progress report, May 1, 1995-April 30, 1996.
Open Access
Phylogeography and character congruence within the Hoplias malabaricus Bloch, 1794 (Erythrinidae, Characiformes, Ostariophysi) species complex
(Colorado State University. Libraries, 1996) Dergam, Jorge A., author; Behnke, Robert, advisor; Black, William C., IV, committee member; Kondratieff, Boris C., committee member; Fausch, Kurt D., committee member; Stack, Stephen, committee member
I analyzed patterns of congruence of independent data sets (molecular and karyotypical) within the Neotropical fish species complex Hoplias ma/abaricus Bloch, 1794, at the local and at the macrogeographic levels. In two locales of sympatry of fish with different karyotypes (cytotypes) in Argentina and Brazil, the patterns of congruence were interpreted as evidence that the cytotypes are distinct species.
Open Access
Ecological effects of reservoir operations on Blue Mesa Reservoir
(Colorado State University. Libraries, 1997) Johnson, Brett M., author; Stockwell, Jason D., author; Bonfantine, Krista, author; Department of Fishery and Wildlife Biology, Colorado State University, publisher
Annual progress report, May 1, 1996-April 30, 1997.
Open Access
Upper Eagle River Valley elk study: progress report on 1996 activities, volume 1
(Colorado State University. Libraries, 1997-05-15) Phillips, Gregory E., author; Alldredge, A. William, author
Open Access
Ecological effects of reservoir operations on Blue Mesa Reservoir
(Colorado State University. Libraries, 1998) Johnson, Brett M., author; Stockwell, Jason D., author; Department of Fishery and Wildlife Biology, Colorado State University, publisher
Annual progress report, May 1, 1997-April 30, 1998.
Open Access
Refine modeling tools to forecast effects of dam operations on reservoir food webs
(Colorado State University. Libraries, 1998) Johnson, Brett M., author; Andre, Mary, author; Department of Fishery and Wildlife Biology, Colorado State University, publisher
Annual progress report, March 24 - August 1, 1998.
Open Access
Evaluating greater sage-grouse brood habitat using human-imprinted chicks
(Colorado State University. Libraries, 2004) Huwer, Sherri Lynn, author; Anderson, David, advisor; Remington, Tom, committee member; White, Gary, committee member; Irlbeck, Nancy, committee member
Greater sage-grouse ( Centrocercus urophasianus) populations are experiencing long-term declines throughout their current range. Several researchers have suggested that the quality and availability of brood habitat may be limiting populations through reductions in the recruitment of young. In order to effectively manage brood areas, reliable information is needed on chick resource requirements and the role of various components of the habitat in chick growth, development and survival. Forb abundance has been identified by several studies as an indicator of brood habitat quality, but no studies have quantified the direct effects of forb abundance on sage-grouse chicks. A promising method for conducting such studies involves using human-imprinted sage-grouse chicks in field experiments. In 2002 and 2003, I conducted field experiments in Middle Park and Moffat County, Colorado, respectively. The objectives of these studies were (1) to develop and evaluate methods for acquiring human-imprinted sage-grouse chicks and using them in field experiments; and (2) to quantify the effects of 3 levels of forb abundance (i.e., < 10%, 10 - 20%, and >20%) in brood habitat on the growth of these chicks. The egg acquisition, incubation, imprinting, and field exposure methods used resulted in human-imprinted sage-grouse chicks that were successfully used in field experiments. These studies showed that using human-imprinted sage-grouse chicks in field experiments is, potentially, a very informative approach to investigating a variety of grouse-habitat relationships. In 2002, there was no evidence that forb abundance in the exposure areas had an effect on the rate of mass gain or feather growth. However, in 2003, the mass gain and feather growth rate of chicks increased with increasing forb abundance. Previous studies have shown a correlation between chick mass and long-term survival. Management actions that increase forb abundance in brood areas with < 20% forb abundance may, therefore, lead to increased chick survival and sage-grouse productivity.
Open Access
Predation and nest success of forest birds in native and non-native habitat on Saipan, Mariana Islands
(Colorado State University. Libraries, 2005) Sachtleben, Thalia, author; Savidge, Julie A., advisor
The primary causes of extinctions and declines of birds on islands are predation by non-native mammals (e.g., rats and feral cats) and the removal or alteration of indigenous forests. The impact of various exotic predators and extreme modification and removal of native forest on Saipan on the nesting success of the native avifauna had not been examined. Thus, I undertook this research on the island of Saipan in 2003 and 2004 to: (i) quantify nest densities in native and non-native forest, (ii) assess nest survival and predation rates on nests in native and non-native forest, (iii) determine whether certain nest site characteristics made nests more vulnerable to predators, and (iv) identify predators of nests of target bird species. My target species were the Nightingale Reedwarbler (Acrocephalus luscinia; federally listed as endangered) and three of the more common forest species, the Golden White-eye (Cleptomis marchei), Bridled White-eye (Zosterops conspicillatus saypani) and Rufous Fantail (Rhipidura rufifrons saipanensis). The Golden White-eye is an endemic species, while the latter two are endemic subspecies. Nest densities were influenced by forest type in 2003, and by avian species, forest type, and sampling period in 2004. Daily nest survival rates varied by nest stage and species. For Bridled White-eye , daily survival rates differed by year, whereas daily survival rates were constant across years for Golden White-eyes and Rufous Fantails. In 2003, daily nest survival in all stages for Bridled White-eyes was similar to that of Golden White-eyes and Rufous Fantails. Survival estimates were higher for Golden White-eyes and Rufous Fantails than for Bridled White-eyes in the incubation and nestling stages in 2004. All predators identified by camera were avian, predominantly Micronesian Starlings (Aplonis opaca) and Collared Kingfishers (Halcyon chloris). Results from modeling the effect of nest site characteristics on daily nest survival rates were ambiguous, with much model selection uncertainty. However, there was weak evidence that higher numbers of nest support branches increased survival of Golden White-eye nests, while lower nest concealment (side cover) improved Bridled White-eye nest survival. These results were contrary to my predictions. No nest site variables that I measured appeared to affect Rufous Fantail daily nest survival rates. Although not a target species of this study, I incidentally found the first nests of the Micronesian Honeyeater (Myzomela saffordi rubratra) on Saipan. I report my descriptions of the nests, nestlings, and parental behavior in Chapter 2. Measured nests (n = 3) averaged 46.7 mm in cup diameter, 65.7 mm in outer diameter, 41.3 mm in cup height, and 55.3 mm in external nest height. Nesting materials were primarily vine tendrils and what appeared to be Casuarina equisetifolia needles. Nests, nest placement and adult bird behavior appeared similar to those reported for this species prior to its extirpation on Guam.