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At least 559 records · Page 31Linked to original sources
USGS1975

Status of the wolf in Michigan, 1973

Wolf ( Canis lupus ) numbers in Michigan's Upper Peninsula declined from an estimated 45-50 animals in the mid-1950s to near extinction in 1973, probably because of overharvesting through the bounty system. Sporadic breeding and occasional immigration of wolves from Ontario and Minnesota are postulated to be the factors tending to maintain the present population at the level of perhaps six individuals, with illegal shooting and incidental capture by coyote bounty trappers apparently suppressing it.

Michigan↗
USGS1977

Energy allocation patterns of a sprouting and nonsprouting species of Arctostaphylos in the California chaparral

The r- and K-selection theory was used to generate testable hypotheses about patterns of energy allocation in two chaparral shrubs of different reproductive strategies. Terminal-branchlet vegetative and reproductive biomass of the nonsprouting Arctostaphylos glauca and the sprouting A. glandulosa were sampled in a 23-year-old and a 90-year-old stand of chaparral to test the predictions that: (1) the terminal vegetative growth (g dry weight/m 2 of areal coverage) would be equal in the two species, in both stands; (2) oven dry weight (g) of reproductive parts/m 2 of areal coverage would be greater in A. glauca than in A. glandulosa in both aged populations; (3) allocation to reproductive parts by the shrubs in the 23-year-old stand would be greater than (or equal to) that of the 90-year-old shrubs. The amount of terminal vegetative growth was equal for both species in the 23-year-old and the 90-year-old stands. There was no statistically significant difference in the weight of fruits produced by the two species in the 23-year-old stand. However, fruit production by A. glauca was significantly greater than by A. glandulosa in the 90-year-old stand. Fruit production was also significantly greater for the older A. glauca shrubs than for those in the 23-year-old stand. The relationships of rainfall pattern and age of shrubs to fruit production are discussed.

California↗
USGS1981

Return of the gray wolf to Wisconsin

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.

Wisconsin↗
USGS1978

Reproduction of raccoons (Procyon lotor) in North Dakota

Necropsies and observations of captive and radio-equipped individuals provided reproductive data from a raccoon population in the northern prairies. The mean parturition date of adult females was 8 May and the mean litter size was 4.8. Only two of the 14 yearling females examined prior to 1 July were pregnant; they had estimated parturition dates of 20 May and 22 June. Penes of most yearling males became extrusible in July or August. Testes weights and sperm smears suggest that yearling males in North Dakota are not reproductively active. Reproductive patterns of raccoons near the northern periphery of their range and those at lower latitudes are compared and discussed.

North Dakota↗
USGS1980

Ecology of a Maryland population of black rat snakes (Elaphe o. obsoleta)

Behavior, growth and age of black rat snakes under natural conditions were investigated by mark-recapture methods at the Patuxent Wildlife Research Center for 22 years (1942-1963), with limited observations for 13 more years (1964-1976). Over the 35-year period, 330 snakes were recorded a total of 704 times. Individual home ranges remained stable for many years; male ranges averaged at least 600 m in diam and female ranges at least 500 m, each including a diversity of habitats, evidenced also in records of foods. Population density was low, probably less than 0.5 snake/ha. Peak activity of both sexes was in May and June, with a secondary peak in September. Large trees in the midst of open areas appeared to serve a significant functional role in the behavioral life pattern of the snake population. Male combat was observed three times in the field. Male snakes grew more rapidly than females, attained larger sizes and lived longer. Some individuals of both sexes probably lived 20 years or more. Weight-length relationships changed as the snakes grew and developed heavier bodies in proportion to length. Growth apparently continued throughout life. Some individuals, however, both male and female, stopped growing for periods of I or 2 years and then resumed, a condition probably related to poor health, suggested by skin ailments.

Maryland↗
USGS1979

Prairie dog distribution in areas inhabited by black-footed ferrets

The distribution of black-tailed prairie dog ( Cynomys ludovicianus ) towns was delineated in a 1490 km 2 study area in Mellette County, South Dakota, and was examined to determine the characteristics of black-looted ferret ( Mustela nigripes ) habitat. Between 1964 and 1974, black-looted ferrets were observed on 14 prairie dog towns in this area. Eighty-six prairie dog towns, located throughout the study area, were not randomly distributed; towns were paired or clumped in spatial distribution. Mean distance between a town and its nearest neighbor was 2.4 km; mean distance between a ferret-occupied town and the nearest town was similar, 2.7 km. Management recommendations are to maintain at least eight towns per township, each at least 12 ha in size. Of these eight towns, two or more should exceed 40 ha.

South Dakota↗
USGS1979

Relating residue in raccoon feces to food consumed

Feeding tests were conducted with captive raccoons ( Procyon lotor ) to permit more meaningful interpretation of food habit data obtained from fecal analysis. Ten diverse types of natural foods were offered in 20 tests. Digestibility coefficients were calculated that ranged from 3.6 for dry sunflowers, where considerable residue was recovered, to infinity for earthworms and boned meat where no residue was recovered. The influence of differences in both food and animal behavior on digestibility coefficients was significant (ANOVA, F<0.001). The use of digestibility coefficients to adjust quantitative estimates of fecal residue or to predict biomass consumed is of questionable value with raccoons due to variability in foods consumed and behavior of individual animals.

American Midland Naturalist↗
USGS1982

Reoccurrence of caribou in Minnesota

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.

Minnesota↗
USGS1982

Nocturnal activity and foraging of prairie raccoons (Procyon lotor) in North Dakota

Nocturnal activity and foraging of 39 radio-equipped raccoons ( Procyon lotor ) in eastern North Dakota were studied from April-July in 1974-1976. Sixteen of the raccoons were collected after foraging bouts for stomach content analysis. Raccoon activity consisted of running (13%), walking (49%) and local movement in confined areas (38%). Local movement was foraging on large or locally abundant food items. Adult males traveled farther in a night, ran twice as often, and moved locally only half as often as adult females and yearlings. Differences in activity patterns between adult females and yearlings were not detected. There was no difference among age-sex groups in use of foraging habitats. All raccoons foraged extensively in farmyards and wetlands. Stomach content analysis substantiated foraging determinations obtained by radiotelemetry. Principal foods were grain, aquatic animals, rodents, birds and bird eggs.

North Dakota↗
USGS1982

Scavenging rates of invertebrates in an eastern deciduous forest

Rates at which scavengers located three types of dead insects were measured. All dead insects were taken by ants with a median time of 3.75 min (range 0.33-36 min). This gives strong indirect evidence that such food is in short supply.

American Midland Naturalist↗
USGS1984

Seed predation due to the yucca moth symbiosis

All species of Yucca (Agavaceae) require the pollinator services of a species of moth in the genus Tegeticula ( Lepidoptera : Incurvariidae). These moths oviposit in the ovary of the plants and the larvae are entirely dependent upon Yucca seeds for food. The extent and distribution of larval seed predation was examined in nine Yucca species in the southwestern United States. The proportion of seeds destroyed by the yucca moth ranged from 3 % in Y. schidigera from coastal southern California to 45 % in one population of Y. angustissima from southern Utah. This sampling was done in 1979 at which time the Y. schidigera population averaged 0.6 larvae per fruit and the population of Y. angustissima averaged 9.3 larvae per fruit. A second sampling of these populations in 1982 averaged 0.5 for Y. schidigera and 5.6 for Y. angustissima . Several species showed significant differences between populations in the number of larvae per fruit. Contrary to expectation, based on the dogma that fruit production is dependent upon Tegeticula pollination (which is always followed by oviposition), a large number of fruits were found without larvae. The proportion varied greatly between populations but was as high as two thirds of all fruits in some populations. Observations suggested that these flowers had been pollinated by Tegeticula and the moths had oviposited in them but that the eggs failed to hatch.

American Midland Naturalist↗
USGS1984

Chance-corrected classification for use in discriminant analysis: Ecological applications

A method for evaluating the classification table from a discriminant analysis is described. The statistic, kappa, is useful to ecologists in that it removes the effects of chance. It is useful even with equal group sample sizes although the need for a chance-corrected measure of prediction becomes greater with more dissimilar group sample sizes. Examples are presented.

American Midland Naturalist↗
USGS1984

Post-fire recovery of California coastal sage scrub

Postfire regeneration of the shrub and herb vegetation on eight coastal slopes of California coastal sage scrub was studied in the first two growing seasons after fire. All shrub species resprouted with the exception of the suffrutescent Lotus scoparius , though it is not known if this species was alive prior to the fire. It was estimated that 70% of the prefire shrub populations resprouted and these sprouts covered one third of the ground surface by the end of the second season. In contrast to chaparral, seedling establishment from soil-stored seed was low (∼ 102-103/ha) in the 1st postfire year. Resprouts of most major species ( Artemisia californica , Encelia californica , Haplopappus squarrosus , Eriogonum cinereum ) flowered and set seed in the 1st year. Seedling densities were ∼ 104-106/ha in the 2nd year. Herbs dominated the first postfire season vegetation in number of species, cover and biomass. The magnitude of the postfire herb flora was comparable to that in chaparral after fire and included many of the same species. On several slopes, "pyrophyte endemic" annuals ( Lupinus succulentus , Lotus salsuginosus , Phacelia parryi ) dominated the first season and were rare or absent in the 2nd year. One major distinction between these coastal sage sites and chaparral was that resprouting perennial herbs dominated some slopes in the first postfire season and most slopes in the second season in coastal sage. Seedling recruitment of perennial herbs was rare; 26 of the 28 species were present only as resprouts. Total herb cover was markedly lower in the 2nd year despite the fact that it was a wetter year. Between the 1st and 2nd years, shrub cover ∼ doubled, largely from resprouts, annual herb cover declined markedly and perennial herb cover remained relatively constant. The perennial bunchgrass Stipa lepida was an important component of the herb flora on all slopes and was the only species (herb or shrub) to exceed 1/m2 on all eight slopes.

California↗
USGS1987

Regeneration patterns of northern white cedar, an old-growth forest dominant

Regeneration of Thuja occidentalis L. was examined in an old-growth dune forest on South Manitou Island, Michigan. To estimate the current status of cedar regeneration, we determined size structure of seedlings and stems and analyzed present patterns of establishment and persistence relative to substrate type. There has been a shift in the pattern of cedar establishment from soil to log substrates. While 97% of all stems ≥15 cm dbh are associated with a soil substrate, 81% of stems ≥2.5cm-<15 cm dbh, and 98% of all cedar seedlings are confined to log substrates. However, few cedar seedlings survive; only 1% of all seedlings on logs are >25 cm tall. There was no significant relationship between the state of log decay and the density of seedlings >25 cm in height, indicating that long-term survival is not dependent on the degree of log decomposition. However, survival on logs is associated with canopy openings. Seedlings >25 cm tall were associated with gaps, and 78% of cedar stems (≥2.5 cm dbh) on logs were associated with a single windthrow gap. Thus, current cedar regeneration in this old-growth forest depends on logs and the canopy openings associated with them.

American Midland Naturalist↗
USGS1989

Wolf population survival in an area of high road density

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.

American Midland Naturalist↗