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We are investigating plant species from the Canadian prairie ecological zone by phenotypic cell assays to discover toxins of biological interest. We provide the first report of the effects of extracts prepared from the shrub Symphoricarpos occidentalis in several human cell lines. S. occidentalis (Caprifoliaceae) extracts are cytotoxic, and, strikingly, treated cells undergo light-dependent vacuolation near the nucleus. The range of irradiation is present in standard ambient light and lies in the visible range (400-700 nm). Vacuolization in treated cells can be induced with specific wavelengths of 408 or 660 nm at 1 J/cm2 energies. Vacuolated cells show a striking phenotype of a large perinuclear vacuole (nuclear associated vacuole, NAV) that is distinct from vesicles observed by treatment with an autophagy-inducing agent. Treatment with S. occidentalis extracts and light induces an intense lamin A/C signal at the junction of a nuclear vacuole and the nucleus. Further study of S. occidentalis extracts and vacuolation provide chemical tools that may contribute to the understanding of nuclear envelope organization and human cell biology. Key Contribution We provide the first description of the biological effects upon human cells of extracts from the toxic plant, Symphoricarpos occidentalis. Treated cells acquire striking nuclear associated vacuoles (NAVs), rarely observed in animal cell biology.

Woody plant encroachment (WPE), the expansion of native and non-native trees and shrubs into grasslands, has led to degradation worldwide. In the Canadian prairies, western snowberry and wolfwillow shrubs are common encroachers, whose cover is currently unknown. As the use of remote sensing in grassland monitoring increases, opportunities to detect and map these woody species are enhanced. Therefore, the purpose of this study is to identify the optimal season for detection of the two shrubs, to determine the sensitive wavelengths and bands that allow for their separation, and to investigate differences in separability potential between a hyperspectral and broadband multispectral approach. We do this by using spring, summer, and fall field-based spectra of both shrubs for the calculation of spectral separability metrics and for the simulation of broadband spectra. Our results show that the summer offers higher discrimination between the two species, especially when using the red and blue spectral regions and to a lesser extent the green region. The fall season fails to provide significant spectral separation along the wavelength spectrum. Moreover, there is no significant difference in the results from the hyperspectral or broadband approach. Nevertheless, cross-validation with satellite imagery is needed to confirm the current results.

The use of aminopyralid combined with metsulfuron for western snowberry control was evaluated with field trials conducted near Rushville, NE. Herbicides treatments consisted of aminopyralid plus metsulfuron, aminopyralid plus metsulfuron plus 2,4-D, 2,4-D alone, and metsulfuron plus chlorsulfuron plus 2,4-D plus dicamba. All treatments were applied in May and June. Sixty days after treatment (DAT) western snowberry control with aminopyralid plus metsulfuron at 0.073 + 0.012 kg ai ha−1 applied in May was 64%, whereas when applied in June, control was 97%. Meanwhile control with 2,4-D was 99 and 78% for the May and June applications, respectively. No major differences between application timings were observed 60 DAT for the rest of the treatments, with control levels ranging from 85 to 99%. One year after application, differences in control between application timings only persisted for 2,4-D. At 365 DAT, western snowberry control with aminopyralid plus metsulfuron at 0.073 + 0.012 kg ai ha−1 was 76 and 78% for May and June applications, respectively. The addition of 2,4-D at 1.1 kg ai ha−1 to aminopyralid plus metsulfuron provided excellent control and was similar to the combination of metsulfuron, chlorsulfuron, 2,4-D, and dicamba for both May and June applications. Grass production and animal carrying capacity were higher after western snowberry control with the majority of the treatments. Aminopyralid plus metsulfuron applied at the lower rate was the exception. The increase in the carrying capacity after western snowberry control ranged from 2.2 to 4.5 animal unit month (AUM). The control of western snowberry resulted in an increase in net income per hectare when compared with the untreated checks, ranging from $4 to $47.9 ha−1. Several options are available for effective western snowberry control during a broader time of application with increased grass production.

Woody encroachment of grasslands is a common phenomenon worldwide, but the consequences of this encroachment for ecosystem carbon storage, particularly belowground are not clear. We quantified total ecosystem carbon in the 3 major natural upland vegetation communities (grassland, shrubland, and forest) at the northern edge of the North American Great Plains. Total ecosystem carbon storage was significantly greater in forest (125.3 mg C·ha-1) than in shrubland (92.4 mg C·ha-1) or grassland (80.7 mg C·ha-1), and this difference was due mainly to greater aboveground biomass, coarse root biomass, and the presence of a humus layer in the forest. Fine and total root biomass were also greater in forest than shrubland or grassland. In contrast, soil carbon was significantly greater in shrubland (80.6 mg C·ha-1) and grassland (75.4 mg C·ha-1) than in forest (48.6 mg C·ha-1). We also investigated whether aboveground variables could be used to predict belowground carbon pools. Soil carbon increased signifi...

Historically, fires occurred throughout the year in the Fescue Prairie of Canada, but little is known about plant community responses to burning at different times of the year. Composition of plant communities was determined annually for 6 years after burning one or three times in a remnant Fescue Prairie in central Saskatchewan. A multiple-response permutation procedure indicated that plant community composition was different in the two burning histories (P

Question: How effective is high-resolution airborne LiDAR technology for quantifying biophysical characteristics of multiple community types within diverse rangeland environments? Location: Native Aspen Parkland vegetation in central Alberta, Canada. Methods: Vegetation within 117 reference plots stratified across eight types, including forest, shrubland, upland grassland and lowland meadow communities, were assessed in 2001 for the height, cover and density of vegetation within various strata (herb, shrub and tree layers). Actual ground data were subsequently compared against modelled values for each community type and strata derived from the analysis of airborne LiDAR data obtained in 2000. Results: LiDAR data were effective for quantifying vegetation height, cover and density of the overstory within closed- and open spulus forest communities. However, LiDAR measurements typically underestimated the height and cover of shrublands, as well as most of the herbaceous communities. Analysis of LiDAR...

In the Great Lakes region, Rhagoletis zephyria Snow (Diptera: Tephritidae) infests snowberries, Symphoricarpos albus variety laevigatus (Fern.) Blake, a western North American native plant that has been introduced widely into eastern North America. These R. zephyria infestations have been hypothesized to be the result of flies that were introduced into eastern North America along with their host plants. In its native range, R. zephyria infests S. albus variety laevigatus, but it infests a related host, Symphoricarpos occidentalis Hook., in the northern Great Plains. Knowledge of the natural geographic and host ranges of R. zephyria is important. R. zephyria is a sibling species of the apple maggot, Rhagoletis pomonella (Walsh), and aspects of R. zephyria biology can be applied to work on speciation mechanisms. Additionally, the possible co-occurrence of morphologically similar R. zephyria and R. pomonella in apple (Malus spp.)-growing regions complicates the positive identification of trap-caught flies in the R. pomonella species group. Here, we examine the hypothesis that R. zephyria in the Great Lakes region has been introduced. Collections of R. zephyria yielded new state/provincial records in Idaho, South Dakota, Nebraska, Wisconsin, Michigan, Pennsylvania, New York, Massachusetts, Maine, and Ontario and Quebec, Canada, and a new host record, S. albus variety albus, which is native to eastern North America. Finding R. zephyria infesting native host plants in the eastern United States leads us to hypothesize that R. zephyria infestations in the Great Lakes region may not be the result of recent (historical) introductions of R. zephyria, but rather they may represent native R. zephyria populations.

Standing crop and species composition in semiarid grassland are linked to long-term patterns of water availability, but grasslands are characterized by large single-season variability in rainfall. We tested whether a single season of altered water availability influenced the proportions of grasses and shrubs in a semiarid grassland near the northern edge of the North American Great Plains. We studied stands of the clonal shrub snowberry (Symphoricarpos occidentalis) and adjacent grassland dominated by the native grasses Stipa spartea and Bouteloua gracilis. Rain was excluded and water supplied in amounts corresponding to years of low, medium, and high rainfall, producing a 2 − 4-fold range in monthly precipitation among water supply treatments. There were ten replicate plots of each water treatment in both snowberry stands and grassland. Grass standing crop increased significantly with water availability in grassland but not inside snowberry stands. Total standing crop and shrub stem density increased significantly with water supply, averaged across both communities. In contrast, water had no effect on shrub standing crop or light penetration. In summary, our finding that water has significant effects on a subset of components of grassland vegetation is consistent with long-term, correlational studies, but we also found that a single season of altered water supply had no effect on other important aspects of the ecosystem.

The annual brome grasses, Bromus japonicus and B. tectorum, are common invaders of the Northern Great Plains. Our objective was to determine if these exotic plants were positively or negatively associated with particular plant species or functional types in a prairie/pine ecotone at Wind Cave National Park, South Dakota. We addressed this issue by sampling at two spatial scales—the landscape scale and the site scale. For the landscape we evaluated species associations across a 3800 ha ecotone using 90 transects. Annual bromes were positively associated with C3 grasses, particularly Agropyron smithii and Stipa viridula, in addition to the shrub Symphoricarpos occidentalis. Annual bromes were negatively associated with trees, C4 grasses, particularly A. gerardii, Bouteloua curtipendula and Schizachyrium scoparium, as well as the shrub Rhus aromatica. For the site scale we assessed relationships at a finer resolution within two 1 ha stands of grassland vegetation. Annual bromes were negatively assoc...

We investigated the relative contributions of size and growth form (biomass allocation) to competitive effects between grasses and shrubs in western Canada for two years. We measured the effects of grasses and shrubs on each other at the population level using removal experiments in natural vegetation. In prairie where shrub abundance was low, shrubs suppressed grasses as much as grasses suppressed shrubs, even though shrubs had six times more standing crop. In adjacent brush clumps, however, where shrub standing crop was 37 times grass standing crop, shrubs suppressed grasses strongly, whereas grasses did not suppress shrubs. Shrubs reduced available soil nitrogen more strongly than grasses did, but shrubs and grasses did not differ in their effects on light or soil water. On a per-gram basis, however, shrubs had smaller effects on light, nitrogen, and water consumption than grasses did. In spite of their smaller per-gram effects on resources, the secondary growth of shrubs allowed them to accumulate more mass and height, and to eventually displace grasses. During this process, competition between the woody and the herbaceous growth form changed from symmetric to asymmetric.

Trees and shrubs establishing in grasslands frequently occur in clumps as- sociated with increased soil moisture and N availability. We tested whether the presence of conspecifics or enhanced soil resources increased the growth and survivorship of a shrub (Symphoricarpos occidentalis) and a tree (Picea glauca) in the presence of the perennial grass (Bromus inermis). Rhizomes of Symphoricarpos and seedlings of Picea were trans- planted into plots either singly or with four nonspecific neighbors, and with grass neighbors present or removed. Half the plots received additional water, N, and shade to simulate a forest environment. Roots and shoots of transplants were harvested after two growing seasons. Soil moisture and available N were lowest at high transplant density, and highest in the simulated-forest environment and in treatments where grass was removed. Transplant survivorship was generally enhanced in plots where grasses were removed and in the simulated-forest environment. Picea survivorship was reduced by grasses in plots without resource manipulations but was unaffected by grasses in the simulated-forest environment, suggesting that the simulated-forest environment enhanced the ability of Picea to compete with grasses. Picea growth, however, was reduced by nonspecific neighbors in all cases. For Symphoricarpos, nonspecific neighbors significantly decreased growth rates with grasses absent but significantly increased growth rates with grasses present. Thus the direct effect of high density in monoculture was to reduce Symphoricarpos growth, but the indirect effect of high density in the presence of grass was to facilitate Symphoricarpos growth. In summary, nonspecific neighbors increased the growth rate of Symphoricarpos in competition with grass, and a simulated-forest environment enhanced the ability of Picea to survive in the presence of grasses. The results support the idea that contagious distributions of woody species invading grasslands enhance woody plant establishment.

We studied the relationship between breeding birds and seral stages of green ash (Fraxinus pennsylvanica) woodlands in central South Dakota between 1990 and 1992. Stands of early seral green ash undergoing primary succession had few small trees with western snowberry (Symphoricarpos occidentalis) in the understory. Some early seral green ash stands resulted from retrogression and had large trees with grass understory. Late seral green ash stands were represented by greater overstory cover consisting of green ash and chokecherry (Prunus virginiana) shrubs and small trees in the understory. Sixty-five of 81 bird species that were observed in these woodlands required woodland vegetation as part of their habitat. Tree- and shrub-nesting birds were the most common and were associated with late seral stages. Ground-nesting birds had mixed relationships between early and late seral stages. Cavity-nesting birds used snags and dead tree branches which occurred in all seral stages. Correlations of birds with vegetation measurements suggested habitat features birds may have selected for in these woodlands.

Aspen poplar, balsam poplar, prickly rose and western snowberry species grow together in pastures of the aspen parkland and reduce the grass and forb production available for grazing. Two 7-yr studies were conducted in east central Saskatchewan to evaluate metsulfuron-methyl (metsulfuron), 2,4-D and a mixture of metsulfuron + 2,4-D for the long-term control of these woody species. Metsulfuron applied at 60 g a.i. ha−1 effectively controlled the four woody species for 7 yr. Control was not improved when 2,4-D at 2 kg a.i. ha−1 was added to the 60 g ha−1 rate of metsulfuron. Aspen poplar control was improved when sucker regrowth was 2-yr old rather than 3-yr old. Grass and forb production was increased 50% from 1023 kg ha−1 in the untreated areas to 1619 kg ha−1 following application of 60 g ha−1 metsulfuron in two experiments averaged over 5 yr. Forbs production decreased from 44% on the untreated area to 8% on areas treated with metsulfuron. Key word: Aspen poplar, balsam poplar, prickly rose, western snowberry, metsulfuron-methyl, 2,4-D

Two 6-yr studies were conducted in southeastern Saskatchewan to evaluate 2,4-D, Metsulfuron methyl (Metsulfuron) and a mixture of 2,4-D + Metsulfuron for the long-term control of western snowberry. Western snowberry is a small shrub that grows in dense stands in rangelands and pastures and acts as a physical barrier to grazing. At the study site, the shrub was growing with native grasses and forbs. Metsulfuron applied at 15 g a.i. ha−1 effectively controlled western snowberry for 6 yr. Control with Metsulfuron was better than with 2,4-D because Metsulfuron killed the crown of the shrub. Control was not improved when 2,4-D was added to Metsulfuron, and at low levels of Metsulfuron the presence of 2,4-D in the mixture rendered Metsulfuron less effective, resulting in a higher canopy cover. Grass production averaged over years and experiments was 788 kg ha−1 for the check and increased to 1328 kg ha−1 after Metsulfuron was applied at 15 g ha−1. Forb production was not affected by the treatments. Key words: Western snowberry, Symphoricarpos occidentalis, metsulfuron methyl, 2,4-D

Seven- and nine-year studies were conducted in northeastern Saskatchewan to compare the long-term control of aspen poplar (Populus tremuloides Michx.) and western snowberry (Symphoricarpos occidentalis Hook.) following single and multiple applications of 2,4-D ester (2,4-DE) or amine (2,4-DA) mixed with dicamba. The area was bulldozed free of trees and was subsequently invaded by aspen poplar and western snowberry regrowth, native forbs and grasses. Herbicides were applied to 2- and 4-yr-old regrowth of aspen poplar, growing with a small uniform stand of western snowberry. A single application of dicamba with either 2,4-DE or 2,4-DA applied at 1.5 + 2.2 kg (a.i.) ha−1 was as effective as two or three consecutive yearly applications for the control of aspen poplar. In one experiment, two consecutive applications of dicamba + 2,4-D controlled western snowberry whereas in the other experiment a single application was adequate. The highest forage production of grasses and forbs occurred following dicamba + 2,4-DE treatments. Following a single dicamba + 2,4-DE application, grass production, averaged over 7 and 9 yr, increased from 38 to 98 g m−2 and from 31 to 83 g m−2, whereas forb production decreased from 48 to 25 g m−2 and from 58 to 48 g m−2, respectively. Key words: Aspen poplar, Populus tremuloides, western snowberry, Symphoricarpos occidentalis, 2,4-D dicamba

traits, and survival status of this taxonomic variety are the subjects of this study. Native Humulus populations were typically associated with only a few tree and shrub species, notably Acer negundo L. [box elder], Crategus spp. [hawthorn], Fraxinus nigra Marsh. [black ash], F. pennsylvanica Marsh. [green ash], Populus balsamifora L. [balsam poplar], P. deltoides Marsh. [cottonwood], Prunus americana Marsh. [wild plum], P. pensylvanica L. [pin cherry], P. virginiana L. [choke cherry], Quercus macrocarpa Michx. [bur oak], Ribes spp. [wild currant], Rosa spp. [wild rose], Salix spp. [willow], Sambucus canadensis L. [elder], Symphoricarpos occidentalis Hook. [snowberry], and Viburnum opulus var. americanum Ait. [highbush cranberry]. Cone (strobilus) variations, exceeding those of leaves and vines, included size (15 mm to 45 mm long), shape (globose to ovoid-conical), and compactness (loose vs. imbricated bracts). Trait diversity of seedling progenies exceeded that of each native population from which they originated. Traits of genetically potential usefulness included dwarf plant habit, precocious cone production, early season flowering, pest repellence, frost resistance, potential drought resistance, and commercially desirable cone structure. Both native-plant and progeny populations were generally free of diseases common to commercial hops, thus offering germplasm that is compatible with institutional hop breeding programs. Persistence of native hop populations from 1989 to 1999 was problematic, with five of 11 selected study sites sustaining complete loss or serious damage. Protection of sensitive riparian habitats occupied by this genetic resource may be warranted, particularly until adequate germplasm sources are secured and reposited for further investigation and use.

Native grassland communities controlled by public agencies become increasingly important to the maintenance of many wildlife species as privately owned grasslands are destroyed or degraded for farming, mining, and development. In turn, wildlife on publicly owned grasslands are affected by the management techniques practiced by local managers. We studied the effects of grazing and prescribed burning on upland-nesting ducks and the structure and type of vegetation from 1980 to 1988 at the Lostwood National Wildlife Refuge (NWR) in northwestern North Dakota. Mallard (Anas platyrhynchos), the most abundant species at Lostwood NWR, had lower (P < 0.05) annual nest densities on experimental and control fields in the later years than in the early years of the study. Spring burning reduced (P = 0.016) nest densities of gadwall (A. strepera). Spring grazing reduced nest densities of gadwall (P = 0.014), and blue-winged teal (A. discors, P = 0.023). Nest density of gadwall increased (P = 0.018) after spring grazing was terminated. On the summer burn/spring graze fields, blue-winged teal had lower (P = 0.010) nest densities after treatments (1987-88) than before treatments (1980-81). Nest success was high (mallard 34%, gadwall 45%, blue-winged teal 31%) but was not influenced (P ≥ 0.16) by the burning and grazing treatments. During the study, the amount of grass/brush increased, whereas the amount of brush and brush/grass decreased on control and treatment fields. During the years with burning and grazing, short vegetation increased and tall vegetation decreased. On the spring graze fields, 1 year after grazing ended the vegetation was similar to that on the control fields. The spring burn and summer burn/spring graze fields recovered more slowly. Brushy species such as western snowberry (Symphoricarpos occidentalis) provided attractive nesting habitat for many upland-nesting waterfowl species, especially mallard, gadwall, American wigeon (A. americana), and northern pintail (A. acuta). Habitat needs of additional species of wildlife that depend on grasslands may need to be considered when deciding how to manage habitat.

The impacts of autumn or spring burning on Symphoricarpos occidentalis were studied in Fescue Prairie in central Saskatchewan. Symphoricarpos density increased two- to three-fold over preburn density in the 1st 2 growing seasons following a burn. Individual shoot weights were approximately one-third those of plants in reference (un- burned) sites. Leaves that were approximately two to three times larger, combined with increased stem densities, enabled plants in burned stands to re-establish a leaf area index equal to reference sites within 2 mo of growth in the 1st growing season. Total standing crop of S. occidentalis was reduced only for the early part of the 1st growing season following burning. In the 1st growing season following burning, xylem water potentials and stomatal conductance of burned plants equalled or exceeded those of reference sites. A delayed effect of burning was expressed in the 2nd growing season, with soil moisture, xylem water potentials and turgor potentials being lower in burned plants than in the reference. Flexibility in resource allocation, with a larger proportion of biomass in leaves, and unaffected or improved water status are adaptive features that enable S. occidentalis to regain its position in the plant community the 1st growing season following disturbance by burning. One-time burning in autumn or spring should not reduce the dominance of S. occidentalis in this region.

Spring fires were conducted in Symphoricarpos occidentalis Hook, stands to determine the effect of fire on the shrub and associated species. The canopy cover of Symphoricarpos had recovered to the level of unburned stands 3 months after fire. Stem density increased three to five times in the first 3 months and then gradually declined during the 2nd and 3rd year. Rubus strigosus increased in cover and stem density when burned and remained at higher levels for the 3 years studied. Forbs increased after fire with the cover of most annuals peaking the first growing season while perennials maintained a higher cover. The density of woody stems and coverage of the shrub, perennial forb, and grass and sedge groups continued to be higher 3 years after burning. There were substantial changes in one or more of frequency, cover, or density of major species.

Annual early spring burning has markedly altered the physiognomy and species composition of aspen parkland vegetation of east-central Alberta. Burning was conducted in April for at least 24 years when soil moisture was normally high. The number of herbaceous species per quadrat doubled while a number of woody species declined slightly. Forest cover declined while grassland increased. In the grass and shrublands, cover of the shrub Symphoricarpos occidentalis and the cool season grass Festuca scabrella declined greatly. Major increases in Calamovilfa longifolia, Carex obtusata, C. heliophylla, and Solidago missouriensis were noted. While the cover of Festuca scabrella and Stipa spartea var. curtiseta decreased; frequency of these species increased. Cover of all shrubs decreased, Populus tremuloides suckers excepted, while density of the fire adapted Elaeagnus commutata, Amelanchier alnifolia, Prunus virginiana, and Populus tremuloides suckers increased. Burning reduced the leaf blade length of all major grasses and sedges. Effect of burning on inflorescence production varied from species to species. Annual herbage production was reduced by burning with the grass and sedge component experiencing about a 50% reduction. Burning caused an increase in organic matter and phosphorus content of the Ah horizon. Burning did not appear to detrimentally affect the nitrogen status of the Ah horizon.

A carpet-covered roller was used to apply 2,4-D, 2,4-D+picloram (9:1 a.i.), and glyphosate at several concentrations to regrowth of aspen and balsam poplars (Populus tremuloides Michx., P. balsamifera L.), and willow (Salix spp.) growing with an understory of rose (Rosa woodsii Lindl.) and saskatoon (Amelanchier alnifolia Nutt.) and to western snowberry (Symphoricarpos occidentalis Hook.). A concentration of 2.25% a.i. of 2,4-D amine controlled aspen poplar for 3 yr, but was not satisfactory on the other species. A concentration of 0.60% + 0.07% a.i. of 2,4-D+picloram controlled both poplars and willow. A concentration of 0.53% a.i. of glyphosate controlled both poplar species adequately, but a 1.6% concentration was needed for good control of willow. None of the treatments was satisfactory on western snowberry because of poor coverage. The percentage of leaf area wetted was low, about 10%, and evidence is presented that better coverage will result in better brush control with more dilute herbicide. Brush too short to be wiped by the roller can rapidly replace the brush killed. Forage species suffered only minor and temporary damage.Key words: Glyphosate, 2,4-D, picloram, roller-applicator, poplar, willow, western snowberry

Bromegrass (Bromus inermis Leyss. cult Carlton) was grown alone or with aspen (Populus tremuloides Michx.), silverberry (Elaeagnus commutata Bernh.), or western snowberry (Symphoricarpos occidentalis Hook.) in the greenhouse for 90 days. Competition reduced the yields of grass and woody plants compared with yields obtained when either was grown alone. Bromegrass grown alone or with aspen or snowberry produced similar total yields, but when grown with high density silverberry, the total yields were significantly greater. The yield of oat forage obtained from soil that had grown a previous crop of woody plants was reduced by previous high production of aspen or snowberry, but oat yield increased with previous high production of silverberry. It is known that another species of the genus Elaeagnus is a nitrogen-fixer and the silverberry plants used in this study were nodulated. The beneficial effects of silverberry on the grass may have been due to nitrogen fixation.

This paper reports on the physiognomy, soils, microclimate, vegetation and animal activity on Mima mounds in Minnesota and presents an hypothesis on origin of these mounds. The mounds vary from 10 to 130 feet in maximum dimension and from 6 to 50 inches in height and occur at a density of about one per acre on 210.5 acres of upland native prairie. Mound vegetation is always distinctly dominated by either grasses, forbs or the shrub, Symphoricarpos occidentalis. The most striking feature of most of the mounds is the disturbance on their soil by pocket gophers (Geomys bursarius), ground squirrels (Citellus spp.), badgers (Taxidae taxus), toads (Bufo hemiophrys) and other animals. This has probably caused the change in vegetation, the lower bulk density, the lack of soil structure, and the increased water permeability. Animal disturbance of the soil may also account for the lack of sod, the high organic content of the subsurface silt loam, the zone of gradation of silt into clay, the discontinuity of the zon...

Quantitative data were collected in 101 vegetational stands in two regions considered to be representative of dune sand vegetation within the grassland zone of Saskatchewan. The purpose was to ascertain species distributional patterns and to attempt to relate these distributions to environmental factors. The data were used to establish two ordinations, one based on physiographic types and the other on compositional similarities between the stands. Areas of active erosion and deposition are dominated by rhizomatous species, particularly Agropyron spp. and Psoralea lanceolata. Juniperus horizontalis is prominent in stabilized blowouts, while stabilized dunes support grassland dominated by Stipa comata, Carex eleocharis, and Koeleria cristata. The most mesic sites, dune depressions and sand flats, are occupied by Carex heliophila and Agropyron spp. with a shrubby overstory of Symphoricarpos occidentalis, Rosa woodsii, and Prunus virginiana. Factorial gradients involved in the distributional patterns include a moisture gradient ranging from xeric to mesic and a stability gradient ranging from active complexes to stabilized areas. The existence of these gradients and the intergradation of the species behavioral patterns offer strong evidence of the continuous nature of dune sand vegetation in Saskatchewan.

Sixty-two pronghorn (Antilocapra americana) neonates were fitted with radio collars in southeastern Alberta and located daily for 58 days or until death. The mean distance between bedded siblings was 73.4 m; they were first seen bedded together at 7 days of age and after 24 days they were together habitually. Mean daily movements and home ranges of fawns increased (P < 0.001) with age. Bedding-site selection and vegetation used by fawns did not change markedly during the 58-day observation period. Fawns preferred heavy native vegetation and under-used cultivated land. Predation by coyotes (Canis latrans) and bobcats (Felis rufus) caused the death of at least 43.5% of 62 marked fawns. Predation was highest on 4-15-day-old fawns, but remained important for animals between 16 and 57 days of age. During the past 10 years in Alberta, annual fawn mortality has approximated 50%. This rate of fawn mortality has not limited the growth of the provincial pronghorn population. J. WILDL. MANAGE. 48(2):542-550 Since the advent of miniaturized telemetry systems (Mech 1967) researchers have shown that predation can be a locally important cause of mortality for pronghorn fawns (Beale and Smith 1973, Barrett 1978, Beale 1978, Bodie 1978, Von Gunten 1978). Beale and Smith (1973) observed that radio collars did not alter the behavior of marked fawns nor change their mortality rate when compared with unmarked animals. Bromley (1978) theorized that bed-site selection by fawns was influenced by predation pressure and habitat structure. In Alberta, the mean mortality of fawns in the first 60 days following parturition approaches 50% (Barrett 1978). Mitchell (1980:139) and Barrett (1981) suggested that increased survival of fawns was a reflection of larger quantities of forb and browse cover. In Idaho, Bodie (1978) related differences in predation rates on fawns to cover type. This paper reports the spatial and behavioral relationships of free-ranging pronghorn fawns for 58 days after birth until they have been integrated into doefawn summer groups. The relationships of fawns to key habitat components of their environment and the effect of predation are also examined. Many individuals of the Alberta Fish and Wildlife Division assisted with fieldwork. Particular thanks go to E. H. Bruns, R. J. Clark, A. R. Cook, K. R. Froggatt, L. D. Gudmundson, D. E. Hofman, H. G. Vriend, and L. A. Windberg. J. P. Chenier, Computing Serv., Univ. of Alberta, assisted with statistical analyses. G. A. Chalmers, Anim. Health Div., Alberta Dep. of Agric., assisted with fieldwork, necropsies, and reviewed the manuscript. G. L. Langford, of G. L. Langford and Associates, Edmonton, assisted with the digitizing and analyses of occupied areas. W. M. Samuel, Univ. of Alberta, Edmonton, B. W. O'Gara, Univ. of Montana, Missoula, and M. J. Dorrance and A. W. Hawley of the Alberta Environ. Cent. reviewed the paper. STUDY AREA AND METHODS The study was conducted during 1975 and 1976 in a 1,054-km2 area of southeastern Alberta. The study area was in the Brown soil zone in part of the mixed-grass prairie region. Mean annual precipitation 542 J. Wildl. Manage. 48(2):1984 This content downloaded from 157.55.39.102 on Mon, 03 Oct 2016 05:11:50 UTC All use subject to http://about.jstor.org/terms PRONGHORN FAWN BEHAVIOR AND MORTALITY * Barrett 543 (1941-70) was 327 mm as measured by the Agriculture Canada research substation at Onefour. Western wheatgrass (Agropyron smithii), blue grama (Bouteloua gracilis), and needle-and-thread (Stipa comata) were the dominant grass species. The primary shrub was silver sagebrush (Artemisia cana), but western snowberry (Symphoricarpos occidentalis) and rose (Rosa spp.) were present in bottomlands and along the many intermittent water courses that transect the area. Topography varied from gently rolling plains to limited hills at an altitude of

The reduction program of surplus elk and mule deer on the National Bison Range in western Montana in 1951 and 1952 provided an opportunity to determine the relative food habits of these two game species (Cervus canadensis and Odocoileus hemionus) on a range that is predominantly grassland. The Pauline pasture was selected as a source of animals. It is 5,566 acres in size. It contains the principal forage species and plant-cover types of the Bison Range and is accessible throughout the year. Fig. 1 illustrates the extent and distribution of the main cover types. The grassland consists largely of Palouse Prairie vegetation, with bluebunch wheatgrass (Agropyron spicatum) as the principal species. The forested portion of the pasture is predominantly Douglas-fir (Pseudotsuga menziesii [P. taxifolia]) on northern exposures and ponderosa pine (Pinus ponderosa) on the southern exposures. Swales and drainage courses contain snowberry (Symphoricarpos occidentalis) and hawthorn ( Crataegus douglasii). Rocky outcrops and stony areas give rise to scattered stands of chokecherry (Prunus demissa), serviceberry (Amelanchier alnifolia), and mockorange (Philadelphus lewisii). Rocky Mountain maple (Acer glabrum) is commonly found as an understory species in the forest type. Ninebark (Physocarpus malvaceus) is abundant at the margins of the Douglas-fir type. Fig. 2 shows the arrangement of types relative to the topography of the pasture.

The great drought which began in the spring of 1933 has made it possible for those living in the Great Plains to witness a vast change in the plant population of this area. In many cases, the original basal ground cover of 70 to 90 percent in our grass lands has been reduced to practically nothing. Numerous species of grasses and forbs have been completely annihilated or at best persist only in the more favorable locations, such as buffalo wallows, north-facing slopes, etc. Deciduous trees and shrubs, such as American elm (Ulmus americanus), hackberry (Celtis occidentalis), green ash (Fraxinus lanceolata), smooth sumac (Rhus glabra), and buckbrush (Symphoricarpos occidentalis), have suffered almost complete losses in many locations. The native red cedar (Juniperus virginiana) is not common in the Great Plains Region. This is especially true from about the 98th meridian westward through Hays, Kan. In the spring of 1935, studies were begun on the native red cedars in the vicinity of Hays, Kan., which seems to be the approximate western limit in which this species is found to grow. Here this tree is usually restricted to north-facing slopes where limestone layers outcrop, or on stream banks where there is some protection from the heat and drought. Figure 1 shows the four locations where studies have been made. The westernmost