This study was designed to determine which seral stages of the regenerating coast forest are most efficient at converting radiant energy into energy available as seasonal deer foods, and if the most efficient stages are most intensively used by deer. Populations of Columbian black-tailed deer (Odocoileus hemionus columbianus Richardson) in coastal British Columbia have been reported to reach maximum levels soon after logging and slash-burning, and to decline as. succession advances. The efficiency of a deer range in producing food has been suggested as a factor influencing reproductive success and thus, population density. Seasonal forage preferences were determined, through rumen content analysis. Cover composition up to four feet in height, and summer and winter estimates of quantity, variety and nutrient quality of the important food species were obtained in different seral stages. These data were then related to the intensity to which deer utilized each seral stage, as indicated by the abundance of pellet groups. An early salal-catsear (Gaultheria-Hypochaeris) association develops three to five years after slash-burning. This type was preferred by deer during spring and early summer. Herbaceous plants formed 60 per cent of the spring-summer diet and were represented by more species, covered more surface area, and produced more available forage in this seral stage than in any other. A salal-Douglas fir (Gaultheria-Pseudotsuga) association develops 12 to 15 years after slash-burning. This type was preferred during autumn and winter. Shrub and coniferous species formed 70 to 80 per cent of the autumn-winter diet and were represented by more species, covered more surface area, and produced more available forage in this seral stage than in any other. In addition, the crude protein, mineral, and ash contents of the important evergreen foods were higher when eaten (autumn-winter) than at other times. Heaviest deer use occurred in the seral stages where these evergreens were most available. The nutrient content of key foods changed significantly with season, and there was evidence of selection by deer of the most nutritious plants available. Tests to demonstrate declines in nutrient levels as seral succession advanced between the fourth and fourteenth years were inconclusive, particularly since there is a likelihood of significant declines occurring in the initial four years. However, seasonal and successional changes in food quality are believed to be a factor influencing range selection. It is concluded that the numbers of deer within a logged unit of coast forest are affected by the efficiency at which food is produced. Numbers within the whole community are affected by the availability of ideal food-producing units for each season. A further hypothesis is suggested which states that sustained populations cannot be expected in a logged coast forest because seral succession will inevitably cause regression of range quality. / Science, Faculty of / Zoology, Department of / Graduate

No description available.

Graduation date: 1964

Sitka black-tailed deer (Odocoileus hemionus sitkensis Sm.) prefer understory forages growing beneath a forest canopy despite a greater abundance of the same plant species in forest clearings. This research examined responses of the deciduous shrub - blueberry (Vaccinium ovalifolium), to test the hypotheses that 1) forage is less nutritious and less palatable when grown in clearings than in forest understories, and that 2) changes in the plant carbon/nitrogen (C/N) ratio in response to light and nitrogen supply determine forage nutritional quality. Responses to irradiance and nitrogen supply were examined with respect to plant physiology, morphology, biochemistry and nutritional quality in three phases : 1) under controlled conditions in a growth room, 2) with manipulations in a field experiment and 3) along natural gradients of light and nitrogen in the native forests. The results were highly consistent from the growth room to the field. Light strongly affected plant physiological responses, including photosynthesis, relative growth rates and growth efficiency, whereas nitrogen had little effect. In regression analyses, leaf morphological properties, including specific leaf weight and leaf succulence, were the best predictors of relative growth rates (R2=.67). Irrespective of nitrogen supply, the biochemical properties of sun leaves included higher concentrations of starch, nonstructural carbohydrates and % lignin + cutin in the cell wall, but lower concentrations of structural polymers, total nitrogen, free amino acids, and ratio of free amino acids : total N, compared to shade leaves. Sun leaves also were slightly higher in digestible energy, much lower in digestible nitrogen and presumably less palatable due to higher tannin concentrations, compared to shade leaves. Tannins were directly correlated to specific leaf weight (R2=.89). Regression equations based upon specific leaf weight, leaf succulence and leaf structural polymers accurately predicted field values for digestible nitrogen (R2=.91) and digestible energy (R2=.96) in foliage. Nutritional properties of blueberry forage grown under variable irradiance in the natural stands matched predictions based upon results from the growth room and field. Compared to even-aged stands and oldgrowth, leaves of plants grown in clear-cuts were similar in digestible energy, much lower in digestible nitrogen, and presumably less palatable due to higher tannin concentrations. / Graduation date: 1990

The objectives of this study were to determine the impact of feeding supplemental energy and protein on the growth performance and on the carcass characteristics of weaned red deer stags. Forty-eight weaned stags were divided into 8 groups and randomly allocated to four dietary treatments. Two levels of energy (E) and protein (P), low (L) or high (H) were obtained by the addition of various amounts of oats and soybean meal (SBM). This trial was divided into 2 phases: For the first 32 weeks (Phase I), diets LE/LP and HE/LP contained 0.5 and 1.0 kg/deer respectively of oats; diet LE/HP consisted of 0.15 kg of oats and 0.30 kg of SBM, and diet HE/HP, of 0.5 kg of oats and 0.35 kg of SBM. In Phase II, the level of supplementation was increased while keeping a constant relationship with the body weight of the deer. The animals were group fed, and offered mixed hay ad libitum. The animals were weighed every two weeks, over 48 weeks and slaughtered at 90.5 to 100.6 kg body weight. Increasing the energy level in the supplement resulted in a substitution effect of grain for forage. As a result, there was no difference in total energy consumption. For this reason, no difference was observed (P > 0.05) between treatments for values of ADG or final weight. Feeding supplemental protein over 368 g/deer/d didn't improve ADG or liveweight (P > 0.05). There were no treatment differences (P > 0.05) in estimates of carcass yield, kidney fat, or tissue depth (GR). Results indicate that concentrate feeding does not stimulate overall growth rate.

Habitat use by mule deer, particularly in relation to use by cattle and by California bighorn sheep on the bighorn winter-spring ranges of Flatiron Mountain was studied from January 1968 through November 1969. Observations were made of (1) food habits, (2) forage production and utilization, (3) the effect of spring and summer utilization on subsequent forage production and (4) spatial and temporal distribution of range use. The results indicate that competition for forage between the native ungulates, deer and sheep, is largely obviated by differential habitat use. This may point to long term evolutionary ecological niche specialization. Some competition for forage occurs for a short period in the early spring when both ungulate species seek succulent new grass, the supply of which is at first limited. Cattle use of the winter-spring ranges was excessive and the diets of cattle and the native ungulates are similar, with the exception that utilization of grass by deer was less. Range use by cattle contributed to intra-specific cattle-deer competition on the grasslands in the spring and cattle-bighorn competition on the grasslands during the winter. The study of spring range utilization indicated that deer use was not detrimental to the 1969 annual forage production in areas used by deer. Spring range utilization by bighorn or bighorn in combination with deer reduced the standing crop of forage produced on the Agropyron spicatum dominated winter-spring ranges. Sheep utilization on South Slope during the summer, when forage growth was declining, further reduced the amount of forage available to the wintering bighorn population. / Land and Food Systems, Faculty of / Graduate

No description available.

The objective of this study was to develop empirical regression equations for describing forest overstory-understory relationships in Arizona mixed conifer forests, and for predicting responses of potential mule deer (Odocoileus hemionus crooki) and elk (Cervus canadensis nelsoni) forage resources following thinning and clearcutting. Data were collected in the White Mountains from unlogged stands, a 2-year-old thinned stand, a 4-year-old thinned stand, an 8-year-old clearcut, and a 16-year-old clearcut. A combination of high variability in understory production (due presumably to inherent structurally-complex overstory conditions) and substantial intercorrelation between independent variables yielded multiple regression equations of questionable value. However, average understory production levels can be predicted using stand basal area alone. Relationships between basal area and understory production components were generally best described using log or log-log functions. Despite considerable diversity in slope and aspect conditions, potential insolation was generally not correlated with understory production; nor was potential insolation per unit of basal area often a better predictor than basal area alone. On unlogged sites production of potential deer forage was positively correlated with presence of spruce and fir, but negatively correlated with combined pine and Douglas-fir composition, and not significantly correlated with aspen composition. Potential elk forage was positively correlated with spruce and combined pine and Douglas-fir composition, but inversely correlated with aspen and fir composition. Understory production was generally inversely related to periodic annual forest growth and thickness of the forest floor. Browse production was generally less related to overstory conditions than herbage components, but was correlated with slope gradient and soil rockiness. Although total browse production could be estimated from basal area data, production of browse potentially useful to deer and elk could not be. Total understory production under virgin mixed conifer stands ranged from about 150 pounds per acre at 50 square feet of basal area (BA) to about 40 pounds at BA 400. The portion of this biomass potentially valuable as deer forage declined from 30% at BA 50 to 8% at BA 400, while elk forage declined from 49 to 11%. Forbs were the dominant understory component for all stand densities higher than about BA75, but were out-produced by graminoids below this level. Browse was the least productive understory component and increased only slightly with decreasing stand density. Total understory production on the 4-year-old thinned site was higher, but not statistically different than on unlogged sites; however, from 65 to 74% of the biomass consisted of forage potentially valuable to deer and elk. Depending on stand density, understory production under the 2-year-old thinning was comparable to or less than that of unlogged sites. Overstory-understory regression curves were often statistically different between thinned and unlogged stands. Diversity of principal deer and elk forage species increased as stand density declined under both unlogged and thinned stands. Unlogged stands produced slightly more potential elk than deer forage at lower stand densities, but production of deer and elk forage after thinning was nearly identical over the entire range of stand densities sampled on both thinned sites. The 8- and 16-year-old clearcuts produced about 750 and 1160 pounds per acre of biomass, respectively, with about 34% consisting of potential deer and elk forage on the younger site, versus 56% in the older clearcut. The 8-year-old clearcut produced 30% more elk than deer forage, and the 16-year-old site 7% more. The duration of beneficial deer and elk forage responses following clearcutting appears substantially longer than 16 years where tree regeneration is unsuccessful.