Geology topics
Publications and source records attributed to L. David Mech.
Wolf mortality in a high-road-density area of Minnesota exceeds that in an adjacent wilderness, and is primarily human-caused. The wolf population there is maintained primarily by ingress from the adjacent wilderness areas. A road density of 0.58 km/km 2 can be exceeded and the area still support wolves if it is adjacent to extensive roadless areas.
We compared the nutritional status of free-ranging white-tailed deer ( Odocoileus virginianus ) in 3 natural yards and 1 yard where deer were supplementally fed from 1 January to 31 March 1985 in northeastern Minnesota. We monitored deer nutritonal status by sequential collection and chemical analysis of urine in snow (snow-urine) for urea nitrogen (U), sodium (Na), potassium (K), calcium (Ca), and phosphorus (P). Dilution of urine by snow was corrected by comparing these data as ratios to creatinine (C). All deer remained in an early phase of undernutrition; however, declining trends of U:C, Na:C, and K:C in 2 natural yards indicated increasingly inadequate nutrition as winter progressed. Unaltered values of these ratios and P.C in snow-urine collected from the third natural yard reflected stable levels of nutrient availability. Significant (P < 0.05) elevations of Na:C, K:C, and P:C in 2 natural yards with similar snow regimes suggested initiation of nutritional recovery in deer during late March. In contrast, deep snow in the third natural yard restricted feeding activity and was associated with ratios that remained diminished. Elevated U:C, Na:C, and K:C provided physiological evidence of the higher nutritional status of supplementally fed deer throughout winter and their ability to increase nutrient intake during late March despite prolonged deep snow cover. Frequent and quantitative assessments of the physiological status of deer by snow-urine analysis provided an improved understanding of the relationship between snow cover and the nutritional well-being of these deer.
Feeding and fasting trials were conducted with 2 groups (A and B) of 4 gray wolves ( Canis lupus ) each during January 1980. The groups were fed for 9 days and fasted for 10 days in a cross-over design. Blood and urine samples and weight data were collected every 2-3 days during each trial. Hemoglobin (Hb) concentrations, red blood cell (RBC) counts, and hematocrits (HCT) were elevated in both groups during fasting. White blood cell (WBC) counts, serum urea nitrogen (SUN), triiodothyronine (T3), and insulin concentrations decreased during fasting in Groups A and B. Mean corpuscular hemoglobin concentration (MCHC), serum cholesterol, triglyceride, and iron (Fe) concentrations were diminished in fasted Group A wolves compared to fed Group B. Creatine phosphokinase (CPK) concentrations were elevated in fed Group A wolves. Serum creatinine (C) concentrations were reduced in both groups during feeding. Urinary urea: creatinine (U:C), potassium:creatine (K:C), and sodium:creatinine (Na:C, pooled Group A and B data) ratios decreased in fasted wolves. Differences were not found between fed and fasted wolves for mean corpuscular volume (MCV), serum cortisol, glucose, calcium (Ca), bilirubin, serum glutamate-oxaloacetate transaminase (SGOT), serum glutamate-pyruvate transaminase (SGOT), serum glutamate-pyruvate transaminase (SGPT), alkaline phosphatase, and luteinizing hormone (LH) concentrations, total iron binding capacity (TIBC), and urinary calcium: creatine (Ca:C) ratios. Analysis of multiple blood or urine samples collected from free-ranging wolves would be useful in enabling researches and managers to identify the nutritional status and general health of wolves over time.
Urine deposited in snow by wild gray wolves ( Canis lupus ) and by fed and fasted captive wolves was analyzed for urea nitrogen, calcium, sodium, potassium, and creatinine. Ratios of the elements with creatinine were considerably higher for fed than for fasted animals, and ratios for fed wolves compared favorably with ratios from wolf urine in snow along trails leading from kills. Thus, wolf urine in the snow can indicate whether wolves have fed recently, and a series of such urine collections from any given pack can indicate relative nutritional state.
The effects of dietary protein, fasting, and refeeding on urinary characteristics of 9 captive, female white-tailed deer ( Odocoileus virginianus ) were studied from 23 February to 3 May 1984. Urinary sodium (na) and potassium (K) were diminished in fasted deer after 2 and 4 weeks. Renal excretion of Na and K were lower, whereas urinary phosphorus (P) was higher in fasted deer compared to deer fed high protein-high energy (HPHE) diets. Urinary P excretion of the fasted deer was also greater than in a low protein-high energy (LPHE)-fed group. Urinary area excretion of fasted deer was similar to that of deer fed low and high protein diets. One fasted deer died during the study and exhibited notably high excretion of urea, Na, K, and calcium (Ca). No effects of the 2 levels of dietary protein on urinary characteristics were detected. Urinary Na:C and K:C ratios wer significantly correlated with Na and K intake. Urinalysis has potential as a sensitive means of monitoring the nutritional status of white-tailed deer. Data are presented as reference values for interpretation of data from deer under less controlled circumstances.
This study examined the effects of dietary protein, fasting, and refeeding on blood characteristics of 9 nonpregnant, female white-tailed deer ( Odocoileus virginianus ) in captivity from 23 February to 3 May 1984. Percent weight loss was greater in fasted deer than in deer fed diets of 2 crude protein levels. Fasting effects were also observed for hemoglobin (Hb), red blood cell (RBC) counts, packed cell volume (PCV), cholesterol, triglycerides, serum urea nitrogen (SUN), potassium (K), glucose, phosphorus (P), insulin, thyroxine (T4), and total protein (TP). Refeeding influenced cholesterol, sodium (Na), and calcium (Ca). Hemoglobin, PCV, Ca, P, and albumin varied with time in fasted deer. Changes over time in the fed deer occurred for several hematological and serum characteristics. Data are presented to serve as reference values for better understanding of data collected from free-ranging deer under less known conditions.
Two hundred nine white-tailed deer ( Odocoileus virginianus ) were radiotracked in the central Superior National Forest, Minnesota, from 1973 through winter 1983-84; 85 deaths were recorded. Annual survival was 0.31 for fawns (< 1.0 years old), 0.80 for yearling (1.0-2.0 years old) females, 0.41 for yearling males, 0.79 for adult ( ≥ 2.0 years old) females, and 0.47 for adult males. Monthly survival rates were high from May through December (0.94-1.00), except for yearling (0.60) and adult (0.69) bucks during the November hunting season. Most mortality occurred from January through April when gray wolf (Canis lupus) predation was an important mortality source for all cohorts. Yearling males were most vulnerable to hunting and adult males to wolf predation.
Survival of 203 yearling and adult white-tailed deer ( Odocoileus virginianus ) was monitored for 23,441 deer days from January through April 1975-85 in northeastern Minnesota. Gray wolf ( Canis lupus ) predation was the primary mortality cause, and from year to year during this period, the mean predation rate ranged from 0.00 to 0.29. The sum of weekly snow depths/month explained 51% of the variation in annual wolf predation rate, with the highest predation during the deepest snow.
Gray wolves ( Canis lupus ) captured in traps with toothed jaws offset 1.8 cm incurred fewer injuries than those captured in 3 other types of steel traps. Few wolves seriously damaged canine or carnassial teeth while in traps.
The dog louse was found on 19 wolves ( Canis lupus ) and six coyotes ( C. latrans ) from Minnesota and Wisconsin during the July-February, 1973 through 1983, period. No evidence was found that lice had any serious effect on wolf survival.
Considerable interest has been expressed recently in establishing gray wolves ( Canis lupus ) into parts of their former range (Bailey 1978, Weaver 1978, Klinghammer 1979, Mech 1979, Henshaw 1982). However, the proper procedure for reintroductions is debatable (Klinghammer 1979). To date, wolf relocations have been conducted in Alaska, where 5 2-year-old captive-reared wolves were released into an area occupied by wolves, (Henshaw and Stephenson 1974, Henshaw et al. 1979) and in Michigan, where a pack 4 wolves was released in a relatively wolf-free area (Weise et al. 1975). Wolf reintroductions are expensive, controversial, and attract considerable public attention. The potential for success of an effort will greatly influence the willingness of agencies to attempt reintroductions. The 9 wolves released in Alaska and Michigan had a high rate of mortality, with humans being the major cause. The present study assessed the survival and behavior of relocated wolves. We hypothesized that relocated wolves, especially pups, would have poorer survival when moved outside a familiar territory.
The volatile constituents of wolf urine were examined via capillary gas chromatography and compared among male, female, and castrate male. Several compounds including methyl isopentyl sulfide, 3,5-dimethyl-2-octanone, and acetophenone were clearly associated with the gender of the animal and many displayed a seasonal dependence. In addition, 2 long-chain aldehydes isolated from urine samples by an HPLC procedure also correlated with the endocrine status of the animal.
Simulations of space use by animals were run to determine the relationship among home range area estimates, variability, and sample size (number of locations). As sample size increased, home range size increased asymptotically, whereas variability decreased among mean home range area estimates generated by multiple simulations for the same sample size. Our results suggest that field workers should ascertain between 100 and 200 locations in order to estimate reliably home range area. In some cases, this suggested guideline is higher than values found in the few published studies in which the relationship between home range area and number of locations is addressed. Sampling differences for small species occupying relatively small home ranges indicate that fewer locations may be sufficient to allow for a reliable estimate of home range. Intraspecific variability in social status (group member, loner, resident, transient), age, sex, reproductive condition, and food resources also have to be considered, as do season, habitat, and differences in sampling and analytical methods. Comparative data still are needed.
At least two caribou ( Rangifer tarandus ) were observed in Cook Co. of northeastern Minnesota from October 1980 through April 1981. This is the first record of caribou in the area since 1924. The nearest records of this species were 224 km NE of the present sightings, and the closest known established population of caribou is 240 km away.
Gray wolves ( Canis lupus ) were studied from April-1972 through April 1974 in the Superior National Forest in northeastern Minnesota by radio-tracking and simulated howling. Based on replies during 217 of 456 howling sessions, the following recommendations were derived for using simulated howling as a census technique: (1) the best times of day are dusk and night; (2) July, August, and September are the best months; (3) precipitation and winds greater than 12 km/hour should be avoided; (4) a sequence of 5 single howls should be used, alternating 'flat' and 'breaking' howls; (5) trials should be repeated 3 times at about 2-minute intervals with the first trial at lower volume; and (6) the trial series should be repeated on 3 nights as close to each other as possible. Two censuses are described: a saturation census and a sampling census.
Five gray wolf ( Canis lupus ) specimens were examined from Wisconsin from 1975 through 1979; each had been killed by human beings, accidentally or intentionally. This confirms the presence of wolves in Wisconsin and supports the hypothesis that human-related mortality is the factor limiting the population.
No abstract available.
No abstract available.