The Rocky Mountains And The Southwest: Using Feature Names To Study Two Iconic Subregions In The American West

Geographic regions can be defined in many ways, including via physiography, historical development patterns, language, and culture. After broadly surveying different methods of regionalization and their influences on studies of the American West, this article uses a vernacular‐mapping approach to: first, propose distinctive toponyms that are relatively unique to cultures situated in the American Rocky Mountains and Southwest areas; second, map the spatial distributions of these toponyms across the western American landscape; and, third, compare the resulting distributions to the geographies of western businesses that incorporate regional terms into their corporate names. Notably, while the Rocky Mountains and the Southwest are iconic American regions that have captured the imagination for centuries, their cultural geographies are relatively underexplored in the literature. This article makes a modest contribution to this research gap by using geographic information systems (GIS) to map high concentrations of culturally distinctive feature names. The results reveal that the boundaries of vernacular Southwest and Rocky Mountain regions correspond relatively well with boundaries delineated with physiographic characteristics     

Sustaining Rocky Mountain Landscapes: Science,Policy, and Management for the Crown of the Continent Ecosystem

In this commentary, we wish to draw from Kathryn's experience in Askole to complicate the argument we developed in favor of an autoethnographic sensibility in the earlier article in this issue (Butz and Besio 2004 ButzDavid KathrynBesio 2004 The value of autoethnography for field research in transcultural settings. The Professional Geographer 56 3 350 60 [Google Scholar]). Just as we used David's first-person singular voice in much of that article, we use Kathryn's voice here to reflect the central influence of her research circumstances on the points that we make. We will return to the first-person plural voice in the commentary's conclusion where we attempt to synthesize the lessons of our two sets of research experiences.     

Emergence of the Canadian Rockies and adjacent plains: A comparison of physiography between end-of-Laramide time and the present day

The landscape of the Canadian Rockies in southern Alberta is not a direct result of constructional processes; that is, the ridges and peaks have not been pushed into the positions in which we see them today. Tectonic activity provided original elevation but not mountains: at the end of Laramide time, what are now the front ranges and foothills of the Rockies comprised a high-elevation upland of relatively low relief. The present mountain physiography is the result of 55–60 million years of post-orogenic differential erosion, in which more resistant rocks have been left at higher elevations than less-resistant rocks.The Canadian Rockies and the foothills are developed in a thin-skinned, thrust-and-fold belt created during the Laramide Orogeny; the adjacent Interior Plains cut across foreland basin sediments derived from the mountains. The mountains currently consist of large parts of ridges of well-indurated Paleozoic and, locally, Proterozoic rock alternating with valleys developed in soft Mesozoic clastic rock. In the foothills, where the soft Mesozoic rock is at the surface, relief is subdued, but ridges of more-resistant sandstone rise above shaley lowlands. The plains are relatively flat but also contain erosional outliers of higher paleo-plains-surfaces.Numerous lines of evidence suggest that the mountains and foothills have lost several kilometers of overburden since the end of the Laramide Orogeny, while the western plains have lost at least 2 km, requiring that the local relief of the mountains and foothills that we see is erosional in origin. Local physiography is adjusted to lithology: the mountains have high relief because the exposed sub-Mesozoic rocks can hold up high, steep slopes, whereas the foothills have low relief because the underlying Cretaceous rocks cannot hold up high, steep slopes. The east-facing escarpment at the mountain front is a fault-line scarp along a low-angle thrust.Mesozoic rocks involved in the deformation originally extended all the way across the thrust and fold belt, and physiography of the belt at the end of Laramide time (60–55 Ma) depended mainly on whether Mesozoic or Paleozoic/Proterozoic rocks were exposed at the surface at that time. A reconstruction using critical-taper theory generally agrees with reconstructions from earlier stratigraphic and paleothermometry studies: what are now the front ranges at the eastern edge of the Rocky Mountains were mostly or perhaps entirely covered with Mesozoic rocks and despite that high elevation had a hilly, not mountainous, character. The main ranges, in the central Rocky Mountains, were in part stripped of Mesozoic cover by then and more mountainous. Treeline was higher then, and the thrust belt may have been largely or entirely vegetated. Generation of modern relief in the front ranges, including the escarpment at the mountain front, had to await stripping of Mesozoic rocks and incision of rivers into harder substrates in post-Laramide time.The Interior Plains are an erosional surface that was cut 1 to 3 km below the aggradational top of the foreland basin sediments. Although some of the present low local relief of the plains results from weakness of underlying Cretaceous/Tertiary rocks, the low relief is probably largely related to the process of denudation.     

Spatial Ecology of Pre –Euro‐American Fires in a Southern Rocky Mountain Subalpine Forest Landscape

Natural disturbances such as fires have been widely studied, but less is known about their spatial ecology than about other aspects of them. We reconstructed and mapped pre–Euro‐American fire history in a subalpine forest landscape in southeastern Wyoming, and analyzed the fires using GIS. Mean fire interval varies little with topography (elevation, aspect, slope) and is spatially autocorrelated at distances of at least 2 km. Fires often spread downslope, and spread more than expected from the north and south and less than expected from the west, under the influence of particular synoptic climatic conditions. The landscape of 1868 a.d., at the time of Euro‐American settlement, was strongly influenced by fires. However, it contained large patches of connected forest and few high‐contrast edges, unlike the modern landscape, which is fragmented by industrial forestry and roads. The spatial ecology of the natural fire regime may be a useful guide for management.     

Surface hydrological processes of rock glaciated basins in the San Juan Mountains,Colorado

Glaciers in the western USA contribute summer meltwater to regional hydrological systems. In the San Juan Mountains of Colorado, where glaciers do not exist, rock glaciers serve that function during the summer runoff period. Most rock glaciers in Colorado are located on northern slopes in mountainous areas; however, some rock glaciers in southwest Colorado have different aspects. In this study, we asked how slope aspect and rising air temperatures influence the hydrological processes of streams sourced from rock glaciers in the San Juan Mountains. We focused on three adjacent basins, Yankee Boy basin, Blue Lakes basin, and Mill Creek basin, which share a common peak, Gilpin Peak. Using HOBO® U20-001–04 water-level loggers, streamflow data were collected in each of these basins, below each rock glacier. Air temperature significantly influenced stream discharge below the rock glacier. Discharge and air temperature patterns indicate a possible air temperature threshold during late summer when rock glacier melt increases at a greater rate. The results also suggest that the aspect of rock glacier basins influences stream discharge, but that temperature and precipitation are likely larger components of melt regimes.     

The Role of Thresholds and Fine-Scale Processes in Driving Upper Treeline Dynamics in the Bighorn Mountains,Wyoming

This research investigates whether abrupt changes indicative of a threshold response occurred in the spatial and temporal patterns of tree establishment within upper treeline ecotones in the Bighorn Mountains of north-central Wyoming, with a particular focus on assessing whether treeline advance occurred. Dendroecological techniques were used to reconstruct the spatiotemporal patterns of tree establishment at multiple spatial scales (local and landscape). Increases in the elevational extent of treeline and tree density above timberline were reconstructed for each decade of the 20^th century. Regime-shift analysis was used to detect threshold changes in tree establishment. Marked increases in tree establishment and density occurred at local and landscape scales during the 20th century, particularly during the post-1970 period and in areas above timberline. Varying degrees of treeline advance occurred during this time, yet establishment upslope from timberline was often contingent on the availability of sheltered microsites in the lee of boulders. This highlights the importance of both broad-scale climate inputs and fine-scale site conditions in governing the rate and pattern of tree establishment in high-elevation treeline environments. Overall, the abrupt changes in tree establishment over time and space since 1970 suggest that bioclimatic thresholds can strongly influence ecotonal dynamics at upper treeline.     

Structural control of the morphometry of open rock basins, Kananaskis region, Canadian Rocky Mountains

The morphometry of chutes (couloirs), rock funnels, and open cirques are related to the structure of dissected rock masses in the Kananaskis region of the Canadian Rocky Mountains. Data for ten morphometric variables were derived from digital elevation models of 56 open rock basins. The basins were classified structurally according to the relative orientations of bedding planes and the rock slopes. A hypothesis of no differences in morphometry among structural classes is rejected from the results of nonparametric analysis of variance and paired comparisons of rank scores. Basins on dip and overdip slopes have a distinct size, and those on anaclinal slopes have a distinct width and shape. Variation in morphometry from low compactness and area/relief (chutes) to high compactness and low area/relief (funnels) to high compactness and area/relief (open cirques) corresponds to a change in dominant structure from orthoclinal to dip-overdip to underdip to anaclinal. The dip of bedding planes relative to the slope of rockwalls controls the mode of initial displacement of joint blocks and, thereby, the spatial distribution of the retreat of rockwalls. The angle between the rock slope and the strike of dipping strata determines whether beds of differing stability form chutes and buttresses (orthoclinal slopes), or extend across rockwalls (cataclinal and anaclinal slopes) and retreat at similar rates to form funnels and open cirques. The optimal structure for large compact rock basins is anaclinal, and the least favourable is cataclinal dip-overdip slopes. Topoclimate and other geologic structures may account for variance in morphometry not explained by differences among structural classes.     

The Palliser Rockslide, Canadian Rocky Mountains: Characterization and modeling of a stepped failure surface

This paper presents the results of an investigation of the prehistoric Palliser Rockslide, Rocky Mountains, Canada. Conventional aerial photograph interpretation and field mapping are complemented by terrestrial digital photogrammetry. These techniques allow quantification of the rockslide debris volume and reconstruction of the pre-slide topography. It has been estimated that the volume of rock involved in the most recent large rockslide is 8 Mm³. Terrestrial digital photogrammetry is used in the characterization of the failure surface morphology, which is subdivided into four types of step-path geometry comprising both pre-existing discontinuities and intact rock fractures. Incorporation of these data into various rock slope stability numerical modeling methods highlights a complex failure mechanism, which includes sliding along a large scale curved failure surface, intact rock bridge fracturing and lateral confinement. A preliminary quantification of the contribution of intact rock bridges to the shear strength of the failure surface is presented in terms of the apparent cohesion, apparent tensile strength and cumulative length of the intact rock segments.     

Dendrogeomorphological assessment of movement at Hilda rock glacier, Banff National Park, Canadian Rocky Mountains

Abstract The results of this dendrogeomorphological study provide evidence of the active movement of Hilda rock glacier, a tongue‐shaped rock glacier in the Columbia Icefield region of Banff National Park. Cross‐sectional samples were cut from 44 detrital subalpine fir (Abies Iasiocarpa (Hook.) Nutt.) and Engelmann spruce (Picea engelmannii Parry) boles killed and buried by debris spilling off the steep distal slope of the rock glacier. The samples were crossdated using locally and regionally developed tree‐ring chronologies, and were shown to have been killed between 1576 and 1999. Our results show that Hilda rock glacier has advanced at an average rate of 1.6 cm/year since the late 1790s, with limited evidence of similar rates of activity extending back to the mid‐1570s. This rock glacier activity is believed to be linked to persistent periglacial processes that appear to be independent of the climatic forcing mechanisms known to influence glacier mass balances over the same interval.     

大小兴安岭多年冻土的主导成因及分布模式

大小兴安岭海拔高度由北向南增高对纬度偏低带来的温升具有相对补偿功能,从而使冻土分区界线大大南凸。大兴安岭山地为一个连续的整体,不宜仅将南部视为山地多年冻土,而将中、北部划为高纬多年冻土。多年冻土南界应在黄岗梁山南麓通过。小兴安岭的多年冻土南界应在呼兰河源中山的南麓通过。大兴安岭北端断续多年冻土区应将伊勒呼里山平均海拔1000 m的中山部分包括在内;岛状融区多年冻土区南伸至阿尔山附近终结;小兴安岭南端汤旺河与呼兰河的河源区存在岛状融区多年冻土闭合圈。     

阴山中段山地土地利用类型转换格局分析

利用1990年TM数据和2000年ETM数据,以农牧交错带的阴山山地中段为研究区,分析1990～2000年土地利用类型的空间分异规律,重点探讨各土地利用类型中耕地、林地和草地的变化过程。研究表明,耕地的转移流向主要集中于草地,而草地的转移流向又集中于耕地,林地消失区主要转变为草地。阴山北麓为草地向耕地转变的集中区域;阴山南部是林地向草地转变最为集中的区域;阴山中部土地利用类型相互转化相对较少。在土地利用的垂向变化上,耕地减少区域集中分布于海拔1500～1600m及1700～1850m;而其他土地利用类型向耕地转变的集中分布区域大致在海拔1700～1900m范围;海拔1600-1800m为草地-耕地相互转移变化最为集中的区域;草地面积主要在海拔1450-1600m范围增加,在1650-1800m范围内减少;林地除在海拔2000～2200m范围内与非林地相互转变大致持平外,在其余地区均发生退化。海拔1800m和海拔2100左右是本农牧交错带山地土地利用类型波动最为集中的两个分布区。     

南岭大型真菌多样性

文章介绍了南岭大型真菌多样性研究概况,列举了37种以南岭为模式产地的大型真菌物种的拉丁学名、中文学名和生境及分布,对部分错误鉴定或存疑种类进行了注释,对南岭大型真菌优势科属和区系地理成分进行了统计,并对南岭大型真菌资源多样性保护和可持续利用前景进行了分析。加强南岭大型真菌多样性研究与保护不仅具有重要的科学意义,同时对生态系统稳定、区域环境安全和未来产业发展服务具有重要的现实意义。     

Topographic Shelter and Conifer Establishment and Mortality in an Alpine Environment,Glacier National Park,Montana

We examined the importance of periglacial shelter in the spatial distribution of conifers at and above alpine treeline. Using a detailed field-based method, we sampled a total of 211 conifer patches at three study locations in Glacier National Park (GNP), Montana. Conifers were found to be nonrandom spatial associates of three periglacial shelter types: boulders, terrace risers, and combination shelters. Our results indicate that conifer establishment and survival in this extreme mountain environment is connected to shelter availability and shelter type.     

FLORISTIC PATTERNS ON AVALANCHE PATHS IN THE NORTHERN ROCKY MOUNTAINS,USA

Avalanche paths in the northern Rocky Mountains have transverse zones of plant physiognomic types representing major exogenous environmental gradients related to topography. Species composition was analyzed among these transverse zones. Forty plots on two paths in Montana, USA, were ordinated by detrended correspondence analysis, giving ordination axes for both plots and species. The results of the ordination of the plots did not correspond to their differentation in physiognomic zones. Dominant species of similar physiognomy were widely separated in the ordination of species. Endogenous spatial processes are suggested to explain the more complex floristic pattern. (Keywords: avalanche, floristic patterns, Rocky Mountains, vegetation)     

Glacial Cirques in the Southern Side of the Cantabrian Mountains of Southwestern Europe

A total of 156 glacial cirques located on two different areas in the Cantabrian Mountains (NW Spain) were identified and measured in order to continue and expand the study of these large‐scale erosional forms in European mountains. Environmental variables that may explain cirque distribution (altitude, aspect and lithology), and their most important morphometric features (area, length (L), width (W), headwall height (H), and L/W, L/H and W/H indices), are analysed. Statistical analysis has been applied as indicators of contrast (ANOVA) and association (correlation and regression). Conglomerate analysis (CLUSTER) has been used to discriminate cirque groups based on their morphometric variables. Results show that cirques occur at lower altitudes in the Upper Sil River basin area than in the Montaña Central area due to a lower former equilibrium line altitude (ELA) position. In the Upper Sil River basin, environmental variables appear to have had a strong influence on the location and size of cirques: the largest cirques are located in quartzite rocks at elevations above 2000 m and face N or NE. In Montaña Central, the influence of these factors was more limited as a consequence of higher geological structure control. Cirque sizes generally are modest compared with cirques present in other mountain ranges globally, most likely due to shorter glacial occupancy in the Cantabrian Mountains.     

Using GIS to analyse a severe forest blowdown in the Southern Rocky Mountains

Many studies have helped us understand where blowdowns occur, how forests regenerate and respond to large disturbances. However, few studies have analysed how physical and biological factors affect blowdowns or interact with one another to determine susceptibility to blowdown. These factors range from the natural physical setting to past disturbances, and human-related features, such as roads and timber harvest units. These factors were examined in this study. Patches of the blown-down forest were mapped for the 1997 Routt-Divide blowdown, which affected over 10 000 ha of subalpine forest in north-central Colorado. A systematic sampling scheme was used to extract information on predictors for sampling points inside and outside the blowdown. Data on predictors were used in Classification and Regression Trees (CART) and logistic regression to model blowdown occurrence and severity. Two models were applied, and both were able to predict with an overall success rate of 75% or more. These two models produced similar results, showing that the Routt-Divide blowdown was most influenced by factors pertaining to the physical setting: distance to the Continental Divide, wind exposure, elevation, aspect, and cover type. Surprisingly, soil permeability and water-holding capacity and distance to natural edges (e.g. forest-meadow) were not correlated significantly with the blowdown pattern.