An ecological study on the Morgan Creek and the East Fork of the Salmon River, Idaho, Bighorn Sheep herds was conducted from July 1, 1966 to February 28, 1970. The Morgan Creek population numbered about 100 animals upon termination of the study. The trend of this population was downward. The East Fork population numbered about 50 animals and the trend appeared to be stable or slightly downward. Productivity of both herds was low. Lamb mortality was high and recruitment to the breeding herd low. Low recruitment rates coupled with hunting pressure caused a decl ine in the ram component of both herds. The lungworm-pneumonia complex and scabies mites localized in the ears were common disease-parasite problems for bighorns on the Morgan Creek and East Fork ranges. Poor nutrition was postulated as the reason for endemic disease and parasite problems. Cougars, coyotes, bobcats and eagles were evaluated as mortaility factors. Evidence did not indicate that any of these were a serious limiting factor. Accidents and poaching also were evaluated as mortal ity factors, but it was not possible to determine the extent to which they contributed to mortality. Food habits of bighorns and deer were studied on the Morgan Creek winter range. Bighorns were found to use 69 percent grasses, 27 percent browse and 4 percent forbs. The primary grass utilized was Agropyron spicatum 11 anditfie primary browse was Cercocarpus ledifollus. Considerable competition for forage existed between deer and bighorns. Competition did not occur between bighorns and elk or antelope. Domestic livestock use has converted most of the range in the vicinity of Challis to sagebrush, which is not quality bighorn habitat. Deer numbers have greatly increased because of the habitat change. Livestock now compete with bighorns for the limited amount of remaining grass and deer compete by decimating the mountain mahogany (C. ledifolius. Shortage of protein during the winter is a serious problem for bighorns. Winter range rehabilitation, consisting of sagebrush eradication and accompanied by reduction of deer and domestic livestock usage, is suggested to restore ranges for the benefit of bighorns. Transplanting of bighorns to suitable areas historically inhabited by bighorns is suggested to increase bighorn distribution in Idaho and to stabilize current statewide downward trends In bighorn numbers until winter range rehabilitation problems can be solved. Breeding occurred in November and December, and lambing in May and June. Twinning did not occur. Several trapping methods were evaluated and a total of 43 bighorns were trapped, Of these, 7 were transplanted, 7 were instrumented with radio transmitters, 23 were neckbanded and 6 accidently killed. Morgan Creek bighorn sheep migrated an average of 22.4 airline miles to summer ranges. The shortest migration was 19 miles and the longest 28.5 miles. East Fork bighorns were found to migrate about 17 airline mi les to summer range. Analysis of winter range indicated a canopy coverage of 34 percent for shrubs, forbs and grasses, 42 percent bare soll and erosion pavement and 24 percent natural rock. Forage production was low at 128 to 669 pounds/acre green weight, Big sagebrush contributed 40 percent of the herbage production. Usage on all sites was moderate to excessive. Erosion was very evident, and range condition trend estimated to be downward. Only about 805 percent of the 16,676 acres of winter range within the Morgan Creek study area was quality habitat avai lable to bighorns during most winters. Sagebrush, little used by bighorns, dominated 56 percent of the winter range. Grasses, indicative of quality bighorn habitat, dominated only 17 percent of the winter range. Idaho's statewide bighorn sheep populations have decreased approximately 50 percent since 1960. Ram components have decreased about 85 percent since 1960. Increased numbers of hunters have harvested fewer rams under the two-week open season 3/4-curl regulation and the point of diminishing returns has begun to operate. Depresslng the ram component below an undetermined level may interfere with reproduction. Therefore, a limited harvest by control led permit regulations and controlled distribution of hunters is recommended.

Social interactions and relationships in an unconfined population of Uinta ground squirrels were studied for two years following a 60% reduction in population size. Frequencies and patterns of interactions were evaluated in the context of the breeding cycle and compared to similar data collected before the population reduction. Males defended territories in early spring, within which they courted females. They were highly aggressive toward other males. After the first month of activity, male aggressiveness declined and they occupied individual home ranges for the remainder of the year. Females were tolerant of other squirrels until early in pregnancy, when they became intolerant and established territories of their own. All other squirrels were excluded. Yearling females emerged later than adults, were bred later, and became territorial later. Females maintained territories through gestation and lactation, until the young appeared above ground. Juveniles interacted chiefly with siblings for the first three weeks after emergence. Nuzzles and play bouts were the primary forms of interaction observed. As older juveniles gradually expanded their home ranges, they began to encounter other squirrels. Most such interactions were aggressive. Some juveniles disappeared, apparently due to dispersal. Males were more likely to disperse than females. Frequency of aggressive encounters in the population was affected more by the time of season than by population density per se. Still, there was generally a lower frequency of aggressive encounters under low density conditions. Not all age-sex groups were affected uniformly. Adult and yearling males were involved in encounters less frequently at low density. Late in the season, females of all ages and juvenile males were involved in encounters more frequently despite lower density. Frequency of sexual encounters per initiating male was higher at low density for the last two months of the year, due primarily to unusual yearling activity. At low density there was a fundamental change in the social role of yearling males in the population. Where at high density they were non-breeders and entirely subordinate, yearlings now competed for and courted females, and defended territories against other males. Late in the 1970 season, the exceptionally vigorous yearling male cohort harassed juveniles aggressively and sexually, causing increased dispersal of juvenile males and retarded sexual development of males returning in 1971 as yearlings. Activity of a single cohort at low density thus caused social stresses previously noted only at high density.

The small mammal communities of central Africa are not well understood, and the southwestern section of Gabon has not been previously surveyed except for some recent work in Monts Doudou. At five sites within the Gamba Complex we set out to 1) document the species of terrestrial rodents (Muridae) and shrews (Soricidae) weighing less than 100 g, 2) compare the community composition between inland and coastal sites, and 3) evaluate our sampling protocols. Using a combination of pitfall lines, Sherman live traps, and snap traps we captured 721 individuals of 12 rodent and 10 shrew species in 15,792 trap-nights. The rodent community was dominated by Hylomyscus stella and the shrew community by Sylvisorex johnstoni, in agreement with nearby studies. The coastal sites were less diverse with 3 rodent species and 1 shrew species only found at inland sites. The inland Rabi site had the most diverse small mammal community due to 2 species captured in secondary forests and fields near the oil facility. Our use of pitfalls was essential to our capture of shrews, and our protocol of switching from live to snap traps midway through the trapping period resulted in more species than expected. The ecological factors influencing distribution patterns of small mammals in central Africa is not well understood. We evaluated the role of disturbance at paired inland and coastal sites using landscape variables generated from satellite imagery. Regression analyses revealed that while the amount of forest present at a site was strongly correlated with rodent richness (F = 16.437; df = 1; p = 0.001), shrew richness was negatively correlated with the amount of roads (partial F = 12.232; df = 1; p = 0.007) and rainfall (partial F = 6.035; df = 1; p = 0.036) and positively with elevation (partial F = 6.832; df = 1; p = 0.028). Our results suggest that while disturbance at Rabi has created additional habitats for rodents, the loss of specialist rodents from coastal sites reflects their inability to tolerate the edge-affected, fragmented, and less diverse forests in that region.

The prairie deer region of South Dakota extends west from the Missouri River to the Black Hills. The region borders the states of Nebraska, Wyoming, Montana, and North Dakota, and is approximately 40,000 square miles in extent. Biologists believe that present deer numbers on these prairies are similar to those of pre-homestead days. The present large numbers of deer in certain counties have given many prairie ranchers and farmers cause for concern. The region's first deer season (bucks only) in 1952 resulted from earlier increases in mule and whitetail herds. After a closed season in 1953, a hunter's choice of "any deer" for 9 days was in force in 1954, and nearly 5,000 deer were killed throughout the region. This type of hunt was changed to bucks only in 1955 for the same length season. The 3 recent harvests on the prairies increased South Dakota's big-game hunting area from about 3,500 square miles in the Black Hills to nearly 30,000 square miles. Some counties had no open season during the 3 previous harvests.

Treponema denticola levels in the gingival crevice become elevated as periodontal disease develops. Oral treponemes may account for as much as 40% of the total bacterial population in the periodontal pocket. The stimuli that trigger enhanced growth of T. denticola and the mechanisms associated with the transmission of these signals remain to be defined. A hypothesis was set that the T. denticola ORFs tde1970 (histidine kinase) and tde1969 (response regulator) constitute a functional two component regulatory system that regulates, at least in part, responses to the changing environmental conditions associated with the development of periodontal disease. The results presented demonstrate that tde1970 and tde1969 are conserved, universal among T. denticola isolates and transcribed as part of a 7 gene operon in a growth phase dependent manner. Tde1970 undergoes autophosphorylation and transfers phosphate to Tde1969. Henceforth the proteins encoded by these ORFs are designated as Hpk2 and Rrp2 respectively. Hpk2 autophosphorylation kinetics was influenced by environmental conditions and by the presence or absence of a Per Arnt Sim (PAS) domain. It can be concluded that Hpk2 and Rrp2 constitute a functional two-component system that contributes to environmental sensing. This study also sought to determine the molecular basis of Hpk2 function in response to environmental stimuli. Hpk2 was shown to bind hemin via a putative heme-binding domain within the PAS domain. Hemin binding to Hpk2 positively regulated its autokinase ability under anaerobic conditions, suggesting that Hpk2 activation may play a role in the migration of T. denticola away from the aerobic zone deeper into developing periodontal pockets. In this study we have generated point mutations of conserved amino acid residues in the sensor PAS domain of Hpk2 and assessed their role in kinase activation under both aerobic and anaerobic conditions depending on their oligomeric state, hence providing a strong basis to correlate ligand binding, kinase activity and oligomeric states of the protein that may provide stability of these complex interactions. Ultimately this study provides a comparative linkage between the responses of PAS domain to sensory inputs controlling access to its kinase domain within which is contained the dimerization domain, which ultimately leads to fine-tuned control of interactions between Hpk2 dimerization and catalytic domain.

Zugl.: Diss.

The elevational distributions of tropical treelines are thought to be determined by temperature, and are predicted to shift upslope in response to global warming. In contrast to this hypothesis, global-scale studies have shown that only half of all studied treelines are shifting upslope. Understanding how treelines will respond to climate change has important implications for global biodiversity, especially in the tropics, because tropical treelines generally represent the upper-elevation distribution limit of the hyper-diverse cloudforest ecosystem. In Chapter 1, I introduce the idea that grasslands found above tropical treelines may represent a potential grass ceiling which forest species cannot cross or invade. I use an extensive literature review to outline potential mechanisms which may be acting to stabilize treeline and prevent forest expansion into high-elevation grasslands. In Chapters 2-4, I begin to explore these potential mechanisms through the use of observational and experimental methods. In Chapter 2, I show that there are significant numbers of seedlings occurring just outside of the treeline in the open grasslands and that seed rain is unlikely to limit seedling recruitment above treeline. I also show that microclimates outside of the closed-canopy cloudforest are highly variable and that mean temperatures are likely a poor explanation of tropical treeline elevations. In Chapter 3, I show that juvenile trees maintain freezing resistances similar to adults, but nighttime radiative cooling near the ground in the open grassland results in lower cold temperatures relative to the free atmosphere, exposing seedlings of some species growing above treeline to lethal frost events. In Chapter 4, I use a large-scale seedling transplant experiment to test the effects of mean temperature, absolute low temperature and shade on transplanted seedling survival. I find that increasing mean temperature negatively affects seedling survival of two treeline species while benefiting another. In addition, low temperature extremes and the presence of shade also appear to be important factors affecting seedling survival above tropical treelines. This work demonstrates that mean temperature is a poor predictor of tropical treelines and that temperature extremes, especially low temperatures, and non-climatic variables should be included in predictions of current and future tropical treeline dynamics.

<p>Quaternary sediments exposed in the banks of the Severn River, Hudson Bay Lowlands, are interpreted as components of four distinct types of depositional complexes. Overconsolidated massive diamicts displaying strong clast fabric orientations and containing channelized, sub-glacial fluvial deposits and glacially shaped clasts, comprise the majority of sediments in the study area. These are interpreted as components of a lodgement till complex. Thin massive diamict units which often display random clast fabric orientations, and laminated fine-grained sediments containing dropstones and diamict clots often occur near the tops of sections. These are interpreted as components of either a glacio-lacustrine or glacio-mairne depositional complex is composed of fossiliferous beach contained in the sediments. An uniquely marine complex, depending on the abundances of formainifera depositional gravels, and estuarine silts and sands. This complex is found only at the very tops of sections, and was probably deposited in the post-glacial Tyrrell Sea. Three distinct ice flow orientations were defined by clast fabric analysis, and measurement of striations on boulder combining these pavements and bedrock surfaces. Three separate lodgement till complexes are identifiedby combining ice flow orientations with data on formainifera abundances, erratic clast lithologies and diamict matrix colours. These lodgement complexes were deposited by ice flowing from three separate ice domes; an earlier Patrician dome, a middle James Bay dome and a younger New Quebec dome.</p> / Bachelor of Science (BSc)

<p>Dynamic muscle strength (1 RM), symptom limited treadmill endurance, and bone mineral density and content, were compared among three groups (5 males and 5 females in each group) of elderly subjects (mean age of72.5 years) who had either continued to weight train twice per week for 5 years (TR), ceased to weight train after 2 years (DETR), or had acted as controls throughout (CON). The TR and DETR trained hard (progressing up to 3 sets at up to 80% of I RM) for 2 years; the TR continued training for an additional 3 years at a maintenance level (2-3 sets at 60-70% 1RM), whereas the DETR stopped training; the 10 CON subjects did not train for the duration of the study but took part in identical testing procedures. After two years of resistance training, dynamic strength in the TR and DETR groups increased significantly above the baseline and CON values for all exercises (p<0.0001). Following 3 years of maintenance level training, leg press, arm curl, and bench press 1 RM (sum of both limbs) in the TR remained 21.6kg (17%), 15.7kg (82%), and 8.3kg (34%) above baseline values respectively. The I RM in the DETR were 18.4kg (14%), 5.3kg (24%), and 1.4kg (9"10) above baseline for leg press, arm curl, and bench press after 5 years, whereas the CON declined over the 5 year period by 18.4kg (9.7%), 4.4kg (19"10), and 3.5kg (6%) respectively. There were non-significant improvements in treadmill performance in the TR and DETR and decline in the CON after 2 years of resistance training. Treadmill performance declined between years 2 and 5 in all groups. Bone mineral density and content were not different among the groups across all time points. We conclude that: 1) The strength gains from long-term resistance training in the elderly are not entirely lost even after 3 years of detraining, 2) The effects are specific to the exercises performed in the training program.</p> / Master of Science (MS)

<p>Thirty women (20-22 y) were randomly assigned to 3 groups of 10: a total body (TB) and a split body (SB) training groups and control group. The SB group performed 4 strength training sessions per week (two upper and two lower body), while the TB group trained both upper and lower body muscle groups together, twice weekly. It took 45-60 minutes to complete training either the upper or lower body muscle groups. Training consisted of five sets of 6-12 repetition maximum (RM) per exercise for 20 weeks. In comparison to the control group, the trained groups decreased relative fat mass (dual-energy x-ray densitometry, -1. 2%, P < 0.006) and increased whole body (3.3%, P < 0.001) and combined arm lean mass (10.0%, P < 0.007) as well as 1 RM (P < 0.0005) arm curl (73%), bench press (28%) and leg press (22%) strength. In contrast, training caused no increase in electrically evoked twitch peak torque or motor unit aotivation (interpolated twitch method) for right knee extension or elbow flexion. Only elbow flexion increased in maximum voluntary isometric strength. Arms were more responsive to training than legs. There appeared to be a trend toward greater gains in strength and muscle size with TB training. However, these differences were not statistically significant. No advantage resulted when a total body strength training session of less than 2 hours was split into separate upper and lower body workouts. Key Words: weight training; training specific and non-specific strength; muscle hypertrophy</p> / Master of Science (MS)