Subalpine Habitats Research Articles

Effect of cycling and constant temperatures on the respiratory metabolism of the tahoe sucker, Catostomus tahoensis (pisces: catostomidae)

1. 1. Resting routine metabolic rates of the Tahoe sucker, Catostomus tahoensis, were measured using static plexiglass respirometers in cycling and constant temperatures over a thermal range typical of this species' summer sub-alpine habitats (8–18°C). 2. 2. Q 10 values approximating three for both cyclic and constant temperatures indicate that this species is thermally sensitive over this temperature range. 3. 3. The metabolic rate of Tahoe suckers in a cyclic temperature regime was not significantly different ( P > 0.05) than for suckers acclimated to constant temperatures at 8 or 13°C, but was statistically higher ( P < 0.05) at 18°C.

Late Quaternary Environments and Biogeography in the Great Basin

AbstractPlant and animal remains found in packrat (Neotomaspp.) middens and cave fill from the eastern and southern Great Basin region reveal the presence of subalpine conifers and boreal mammals at relatively low elevations during the Late Wisconsin. Limber pine (Pinus flexilis) and bristlecone pine (P. longaeva) were important in the late Pleistocene plant communities throughout this region. Spruce (Piceacf.engelmannii) and common juniper (Juniperus communis) were present in some of the more northerly localities, and Douglas fir (Pseudotsuga menziesii) and white fir (Abies concolor) were present in southern and eastern localities. Single needle pinyon pine (Pinus monophylla), common across this region today, was apparently not present north of the Sheep Range of southern Nevada during the Late Wisconsin. Pikas (Ochotonacf.princeps), small boreal mammals present in only a few Great Basin mountain ranges today, were common throughout the region. Heather voles (Phenacomyscf.intermedius) have been found in two cave fill deposits in Nevada, though they are unknown in the Great Basin today. Limber and bristlecone pines are generally restricted to rocky substrates in modern subalpine habitats in the Great Basin, and this may also have been the case when these plants grew at lower elevations during the Late Wisconsin. Subalpine conifers were present on the rock outcrops sampled by the packrat middens, but shrub communities, perhaps dominated by sagebrush (Artemisiaspp.), may have been present on alluvial valley-bottom substrates. Forested habitats would thus have been isolated habitat islands, as they are today. Boreal small mammals, including pikas and heather voles, were able to colonize the Great Basin mountain ranges during the late Pleistocene. We suggest that these mammals were able to survive in the intervening valley-bottoms under a cool-summer climatic regime, and that continuous forest or woodland corridors were not necessary for migration.

Ecological Relationships of Bristlecone Pine

Functional relationships between bristlecone pine (Pinus longaeva Bailey)1 growth characteristics and environmental factors were investigated near Wheeler Peak and Bastian Peak in E-central Nevada. Because of bristlecone pine's intolerance to shading it constituted only a small percentage of the total tree cover on sites favoring good growth rates and dense timber stands. On such sites limber pine (P. flexilis James) and Engelmann spruce (Picea engelmanni Parry ex Engelm.) dominated the stands. On harsher sites bristlecone pine often formed essentially pure, although sparse, stands. Regression analyses (both simple and multiple) and analyses of variance revealed that bristlecone pines are faster growing, taller, straighter and less sensitive to climatic fluctuations on sites where moisture conditions are favorable. Organic carbon, clay and mean air temperature accounted for 83% of the variation in mean annual growth rates of bristlecone pine. Organic carbon and mean air temperature accounted for 55% of the variation in mean sensitivity (a measure of annual variation in ring width) of the trees. Maximum tree age is associated with harsh growing conditions which result in slow growth rates and dense, highly resinous wood. 1D. ?. Bailey (1970) demonstrated seveial important differences between the bristlecone pines and the Rocky Mountain bristlecone pines (Pinus aristata) as described by Engelmann. He proposed that the Great Basin population be considered a separate species, viz., Pinus longaeva Bailey. Nomenclature for other plant species follows Munz and Keck (1959). Introduction Bristlecone pine (Pinus longaeva Bailey) grows and attains great longevity on dry, rocky subalpine habitats in the southwestern United States. Trees over 3000 years old are common in particular habitats and several trees in excess of 4000 years have been reported in California (Schulman and Ferguson, 1956) ; only one bristlecone pine over 4000 years has been found in Nevada (Currey, 1965; Ferguson, 1970b). The longevity and esthetic appeal of the gnarled weather-beaten trees and their habitats have generated much interest among scientists and naturalists. Study of these ancient trees is contributing to many fields of science, including dendrochronology, climatology, geology and archaeology (Ferguson, 1968; Renfrew, 1973; LaMarche, 1974; Wilson, 1975). Yet, knowledge of the longevity and unique growth habit of bristlecone pine is still limited (LaMarche, 1969). The objective of this study was to identify environmental factors which might influence growth and distribution of bristlecone pine in E-central Nevada and to examine functional relationships between tree characteristics, environmental factors and soil properties. Study Area The study areas?Wheeler Peak and Bastian Peak?are E of Ely, Nevada, in the Snake and Schell Creek ranges, respectively, near the geographic center of the Basin and Range physiographic province of western North America. Near Wheeler Peak, bristlecone pine sites lie between 2900 m elevation and timbe rline (3200 m). Slopes are steep and covered with coarse, blocky, quartzitic glacial till. Soil derived from quartzite occupies interstices within the glacial till and supports sparse stands of bristlecone pine, Engelmann spruce (Picea engelmanni Parry ex Engelm.), limber pine (Pinus flexilis James) and scattered shrubs, herbs and grasses. On Bastian Peak, elevation 3274 m, bristlecone pine grows on soils derived from limestone. Slope gradients are steep on the E and W sides of the ridge but gentle to moderate near the crest. Limestone is exposed on the W side of Bastian Peak in

Effects of weather on foraging‐flights of bumblebees (Hymenoptera, Apidae) in a subalpine/alpine area

The foraging activity of bumblebees in a subalpine/alpine area in northern Sweden was related to weather factors (temperature, light, wind and rain) by counting the number of specimens visiting a square (5 × 5 m) with a high density of forage plants. The combined effect of light and temperature was the most important factor regulating the flight activity. The condition of the arctic light‐climate allows bumblebees to fly even at the less light hours of the day. No clear differences according to flight activity were observed between the subalpine/alpine species Bombus balteatus Dahlbom, B. lapponicus (Fabricius) and the species B. jonellus (Kirby), B. pascuorum (Scopoli), B. pratorum (L.), observed in the subalpine habitats. A comparison between the flight activity of queens, workers and males shows that queens are able to fly at the lowest temperatures followed by males and workers at slightly higher temperatures. The relevance of the overlap of the body sizes between the casts is discussed.

The Importance of Arthropods in the Diet of Zapus princeps in a Subalpine Habitat

The Importance of Arthropods in the Diet of Zapus princeps in a Subalpine Habitat

THE POLLINATION ECOLOGY OF AQUILEGIA ELEGANTULA AND A. CAERULEA (RANUNCULACEAE) IN COLORADO

Aquilegia elegantula Greene and A. caerulea James occur in montane and subalpine habitats in the southern Rocky Mountains of western North America. The red and yellow flowers of A. elegantula are nodding, odorless, protogynous, and secrete a concentrated (44%) sucrose nectar in the floral spurs. Seed set in flowers under pollinator exclosures was 12% while seed set in open‐pollinated flowers was 65%. The flowers of A. elegantula are pollinated primarily by the Broad‐tailed Hummingbird (Selasphorus platycercus [Swainson]) and by at least three species of pollen‐foraging bumblebees, of which Bombus occidentalis Greene is the most common. The blue and white flowers of A. caerulea are erect, mildly fragrant, protandrous, and secrete a 26% sucrose nectar. Seed set in caged flowers in the field averaged 39%. in uncaged flowers 54%. The most important pollinators of A. caerulea are the crepuscular hawkmoth, Hyles (=Celerio) lineata (Fabricius) and ten species of pollen‐foraging Bombus. The most abundant bumblebee species, B. occidentalis, is also a frequent nectar thief. Differences in pollination systems alone probably do not constitute an effective anti‐hydridization mechanism between A. elegantula and A. caerulea, but do serve to reinforce differences in habitat and flowering time that distinguish the two species.

The Pollination Ecology of Aquilegia Elegantula and A. Caerulea (Ranunculaceae) in Colorado

Aquilegia elegantula Greene and A. caerulea James occur in montane and subalpine habitats in the southern Rocky Mountains of western North America. The red and yellow flowers of A. elegantula are nodding, odorless, protogynous, and secrete a concentrated (44%) sucrose nectar in the floral spurs. Seed set in flowers under pollinator exclosures was 12% while seed set in open-pollinated flowers was 65%. The flowers of A. elegantula are pollinated primarily by the Broad-tailed Hummingbird (Selasphorus platycercus [Swainson]) and by at least three species of pollen-foraging bumblebees, of which Bombus occidentalis Greene is the most common. The blue and white flowers of A. caerulea are erect, mildly fragrant, protandrous, and secrete a 26% sucrose nectar. Seed set in caged flowers in the field averaged 39%. in uncaged flowers 54%. The most important pollinators of A. caerulea are the crepuscular hawkmoth, Hyles (=Celerio) lineata (Fabricius) and ten species of pollen-foraging Bombus. The most abundant bumblebee species, B. occidentalis, is also a frequent nectar thief. Differences in pollination systems alone probably do not constitute an effective anti-hydridization mechanism between A. elegantula and A. caerulea, but do serve to reinforce differences in habitat and flowering time that distinguish the two species.

Alchemilla austriaca, spec. nova,(Rosaceae) ? eine neue Art aus den Ostalpen

Alchemilla austriaca is a new species which belongs to the group ofA. demissa, A. frigens, A. longana, A. longiuscula, A. semisecta, andA. sinuata. The holotype specimen as well as leaf and flower details are illustrated (Figs. 1–3). A complete character analysis is given, differences and similarities of allied species are presented in two tables, and the position of the group within the genus is discussed.A. austriaca so far is known only from the Austrian Alps and mainly from the central ranges (distribution map: Fig. 4). Its wet subalpine and alpine habitats are characterized by species lists.

Breeding systems and pollination in New ZealandParahebe(Scrophulariaceae)

Abstract New Zealand species of Parahebe are homogamous, self-compatible hermaphrodites. P. canescens, P. catarractae, P. decora, P. hookeriana, P. linifolia ssp. linifolia, P. lyallii, and P. olsenii are predominantly entomophilous, whereas P. birleyi, P. cheesemanii, P. laxa, P. linifolia ssp. brevistylis, P. plano-petiolata, P. spathulata, and P. trifida are predominantly autogamous. The morphological syndromes associated with entomophily and autogamy are described. In Parahebe, lowland, widely distributed species are adapted to entomophily, whereas most species occupying various subalpine, alpine, and nival habitats are adapted to autogamy.

Soil Temperature Effects on Root Respiration and the Ecology of Alpine and Subalpine Plants

Root respiration rates of Geum rossii (R. Br.) Ser. of G. triflorum Pursh, and of populations of Achillea millefolium L. from elevations of 2,400-3,220 m were compared at 4, 10, 18, and 25 C to determine whether soil temperature is important in controlling distribution of plants relative to alpine timberlines. Respiration was measured as a function of oxygen uptake by detached roots and was determined with an oxygen electrode. Comparisons of rates of roots and caudex tissue from mature plants collected in the field before and after 3 wk of growth in cold (4-10 C) or warm (15-25 C) soils and again following reversal of conditions showed that the alpine endemic G. rossii maintained higher rates than the subalpine G. triflorum; "alpine" populations of Achillea likewise had higher rates than populations from more subalpine habitats. Aerial conditions for all plants were about the same. Similar results were obtained in comparing respiration rates of 14-day-old Achillea seedlings germinated and grown at 26 C for 20 h and 10 C for 4 h, with a 16-h photoperiod daily. No differences were observed, however, between seedlings of the two Geum species, apparently due to a strong selection for heat-resistant individuals as indicated by the differences in seedling mortality. The results suggest that there are inherent tendencies for alpine plants to have higher root respiration rates than subalpine plants, which could make them more competitive under alpine conditions but could produce a wasteful metabolic rate in the warmer conditions of the subalpine. Estimations of root and shoot growth support our conclusion that soil temperatures could be an important factor in determining plant distribution patterns about alpine timberlines.

Changes in Numbers of Rabbits and their Burrows in a Subalpine Environment in South-eastern New South Wales.

Patterns of distribution and use of rabbit warrens in 540 acres (219 ha) of subalpine habitat during 1963 and 1966-71 are described. The numbers of rabbits and of burrows in which they live can fluctuate independently of each other. It is demonstrated in a marked population that careful measurement of changes in burrow use can be used to estimate changes in the numbers of rabbits using the burrows. The most favourable habitat for rabbits in subalpine regions is raised areas on the floor and sides of valleys in open alpine grasslands, where there are projecting granite tors and moraine-like materials.

Evolution of subalpine and alpine plant groups in New Zealand

Abstract Although some of the plants of alpine and subalpine habitats in New Zealand are derived from ancestors that have been present since Paleogene, or possibly Cretaceous, times, many entered via Australia following the late Pliocene and subsequent elevation of mountains in Malaysia, New Guinea, Australia, and New Zealand. The New Zealand alpine and subalpine habitats only developed in the past few million years, during which they have been profoundly and repeatedly altered by Pleistocene glaciations and finally by man. As these habitats developed in isolation they were colonised mainly by plants derived from Australia, as a result of long-distance dispersal. Westward dispersal, in the face of the prevailing westerlies, is almost ruled out for Australasian plants. In New Zealand, many of them evolved rapidly to produce numerous species in consequence of the processes of adaptive radiation, interspecific hybridisation and recombination, and in many instances self-pollination. These large clusters of sp...

Alpine disturbance studies: Olympic national park, USA

Measurements of downslope rock-creep, of the slow rate of plant establishment on alpine and subalpine road-cuts, and of the reduction in plant cover and plant production in two alpine plant communities, illustrate the degree of disturbance that can occur. The development of large trails or roads should not be permitted in areas of such active downslope rock movement, because of the natural rate of mass-wasting. If more people are to visit and enjoy the alpine communities, asphalt paths to confine their walking are desirable, for trampling experiments showed that plant cover and plant production were rapidly reduced in even one season of light use. Recovery during the following year was, however, quite rapid—especially in the snow-bank community. Different alpine and subalpine habitats have different sensitivities to disturbance, and any plans for increased human use must incorporate this kind of information.

Competition Between Two Chipmunk Species (Eutamias)

Two chipmunk species were studied in the mountains of western Alberta from 1961 to 1965. One species, Eutamias minimus, is largely confined to alpine habitat but also ranges into subalpine forest, where its distribution narrowly overlaps that of E. amoenus. The fundamental niches of the two species, estimated from their habitat distributions elsewhere, are both reduced in western Alberta. Mark and recapture trapping in an overlap zone showed that neither species selected habitat deficient in cover and both species made the same relative use of the available forest. The boundary between the two species was not clearly predictable by obvious habitat features. Eutamias amoenus luteiventris is larger than E. minimus oreocetes and, on an average, has larger litters, earlier maturity, and higher populations density. The two species take similar foods, depending on availability in their respective habitats, but the food consumption of individual minimus is less than that of amoenus. In the laboratory, amoenus was highly successful in interspecific encounters with minimus, regardless of whether or not minimus was a resident of the observation cage. In addition, amoenus dominated minimus in a mixed—species group and minimus exhibited avoidance behavior under such conditions. The highly developed aggressive behavior of Eutamias amoenus enables it to exclude E. minimus from subalpine habitats, but the latter survives in alpine situations where its small size is an adaptation to a reduced food supply.

Habitat of Pocket Gophers in Cochetopa Creek Drainage, Colorado

Comparisons were made between some characteristics of soils and vegetation for sites supporting Thomomys talpoides and for adjacent sites not occupied by these pocket gophers in alpine, subalpine and shrub-grassland habitats in the Cochetopa Creek drainage, Colorado. Different species of bluegrasses (Poa spp.), sedges (Carex spp.), cinquefoils (Potentilla spp.), and bluebells (Mertensia spp.) occurred in the alpine, subalpine, and shrub-grasslands. There were 16 species of plants common to the alpine and subalpine, three species of plants oc- curred in both the subalpine and shrub-grasslands and two species occurred in both the shrub-grasslands and the alpine. Alpine skyrocket (Androsace septentrionalis puberulenta) occurred in all three habitats. Plant composition was very similar between sites occupied by pocket gophers and adjacent unoccupied sites. Those differences detected did not appear great enough to account for the presence or absence of pocket gophers. Soils in the alpine were shallower where gophers occurred than were soil depths on unoccupied sites, but in the subalpine and shrub-grasslands soils were deepest at sites occupied by pocket gophers. In general, soils were deep enough to support pocket gopher burrows at all sites sampled. There was a decrease in mean soil temperature with an increase in elevation. Soils inhabited by gophers in the shrub-grasslands varied from about 7% to 12% moisture and those in the subalpine and alpine varied from about 25% to 55%. The rock composition of soils occupied by pocket gophers and adjacent unoccupied soils was similar in the subalpine but in both the alpine and shrub-grasslands the unoccupied soils contained more rocks larger than one-half inch in diameter than did soils supporting pocket gophers. Some pocket gopher mounds were made up of 40% rocks (larger than one-fourth inch in diameter) in the shrub-grasslands, up to 31% in the alpine and as much as 16 % in the subalpine. Pocket gopher mounds contained fewer large rocks than did the topsoil at sites occupied by pocket gophers. It appears that pocket gophers could occupy more area in the alpine, subalpine, and shrub-grasslands than they now occupy.

The Central American Herpetofauna: An Ecological Perspective

Six major herpetological habitats (biociations) are recognized in Central America; these are based principally on the physiognomic characteristics of the vegetation. There are three tropical habitats (evergreen forest, scrub forest, and savanna) and three montane habitats (cloud forest and low montane wet forest, oak-pine forest, and alpine and subalpine habitats including fir forest, pine-cypress forest, and montane meadows). Temperature and moisture are the principal environmental factors affecting the distributions of amphibians and reptiles in Central America. Secondarily, cover in the form of shade or mulch, and suitable breeding sites are significant factors determining the distribution of species. Five major ecological assemblages are defined in the Central American herpetofauna; characteristic species are noted in each, and the geographical distribution of each assemblage is described. The humid tropical and arid tropical assemblages contain the largest numbers of species and are widespread in the lowlands. The humid montane assemblage is characterized by a high degree of local endemism and inhabits cloud forest and low wet forest in the mountainous regions. The arid montane assemblage consists of an impoverished fauna inhabiting oak-pine forests, and the high montane assemblage is made up of a few species living in the alpine and subalpine habitats. A geographical analysis shows that a greater continuity exists in the lowland than in the montane assemblages; the latter often more closely resemble assemblages in the adjacent lowlands than in geographically remote highlands and characteristically exhibit a higher degree of local endemism than the lowland faunas. Climatic fluctuations in the Pleis-