Structural characterization of Turtle Mountain anticline (Alberta, Canada) and impact on rock slope failure

his paper proposes a structural investigation of the Turtle Mountain anticline (Alberta, Canada) to better understand the role of the different tectonic features on the development of both local and large scale rock slope instabilities occurring in Turtle Mountain. The study area is investigated by combining remote methods with detailed field surveys. In particular, the benefit of Terrestrial Laser Scanning for ductile and brittle tectonic structure interpretations is illustrated. The proposed tectonic interpretation allows the characterization of the fracturing pattern, the fold geometry and the role of these tectonic features in rock slope instability development. Ten discontinuity sets are identified in the study area, their local variations permitting the differentiation of the study zone into 20 homogenous structural domains. The anticline is described as an eastern verging fold that displays considerable geometry differences along its axis and developed by both flexural slip and tangential longitudinal strain folding mechanisms. Moreover, the origins of the discontinuity sets are determined according to the tectonic phases affecting the region (pre-folding, folding, post-folding). The localization and interpretation of kinematics of the different instabilities revealed the importance of considering the discrete brittle planes of weakness, which largely control the kinematic release of the local instabilities, and also the rock mass damage induced by large tectonic structures (fold hinge, thrust).

Combining probabilistic land-use change and tree population dynamics modelling to simulate responses in mountain forests

Altitudinal tree lines are mainly constrained by temperature, but can also be influenced by factors such as human activity, particularly in the European Alps, where centuries of agricultural use have affected the tree-line. Over the last decades this trend has been reversed due to changing agricultural practices and land-abandonment. We aimed to combine a statistical land-abandonment model with a forest dynamics model, to take into account the combined effects of climate and human land-use on the Alpine tree-line in Switzerland. Land-abandonment probability was expressed by a logistic regression function of degree-day sum, distance from forest edge, soil stoniness, slope, proportion of employees in the secondary and tertiary sectors, proportion of commuters and proportion of full-time farms. This was implemented in the TreeMig spatio-temporal forest model. Distance from forest edge and degree-day sum vary through feed-back from the dynamics part of TreeMig and climate change scenarios, while the other variables remain constant for each grid cell over time. The new model, TreeMig-LAb, was tested on theoretical landscapes, where the variables in the land-abandonment model were varied one by one. This confirmed the strong influence of distance from forest and slope on the abandonment probability. Degree-day sum has a more complex role, with opposite influences on land-abandonment and forest growth. TreeMig-LAb was also applied to a case study area in the Upper Engadine (Swiss Alps), along with a model where abandonment probability was a constant. Two scenarios were used: natural succession only (100% probability) and a probability of abandonment based on past transition proportions in that area (2.1% per decade). The former showed new forest growing in all but the highest-altitude locations. The latter was more realistic as to numbers of newly forested cells, but their location was random and the resulting landscape heterogeneous. Using the logistic regression model gave results consistent with observed patterns of land-abandonment: existing forests expanded and gaps closed, leading to an increasingly homogeneous landscape.

Siphonaptera parasites of wild rodents and marsupials trapped in three mountain ranges of the Atlantic Forest in Southeastern Brazil

A study of the associations between small mammals and fleas was undertaken in three areas of the Atlantic Forest in Souhtheastern Brazil: Serra da Fartura, SP, Serra da Bocaina, SP, and Itatiaia, RJ. Trapping of small rodents and marsupials was done every 3 months during 2 years, from June 1999 to May 2001. A total 502 rodents (13 species) and 50 marsupials (7 species) were collected, and 185 hosts out of 552 (33.5%) captured in the traps were parasitized by 327 fleas belonging to 11 different species. New host records were determined for several flea species, and 5 significant associations between fleas and hosts were also found.

U.S. National Parks and "The Tragedy of the Commons" : A contribution to the characterization of U.S. mountain guides' professional practice

This paper aims at presenting the stakes related to the access to protected land in the United States and to its conservation, through the analysis of the professional practice of U.S. mountain guides. From a methodological standpoint, this research is based both on a theoretical analysis grounded in the field of environmental economics and on an empirical study. The authors' starting point is Garrett Hardin's paper, "The Tragedy of the Commons" (Science, 1968), even if it introduces some confusion on the notion of common goods. So as to avoid this confusion, the authors use two theoretical tools pertaining to a typology of common goods and the different property rights that can be applied in National Parks. Finally, they apply this framework to the observations made on the field in Colorado in July 2009.

Risk determinants of acute mountain sickness in trekkers in the Nepali Himalaya: a 24-year follow-up.

OBJECTIVE: Exposure to altitude may lead to acute mountain sickness (AMS) in nonacclimatized individuals. We surveyed AMS prevalence and potential risk factors in trekkers crossing a 5400-m pass in Nepal and compared the results with those of 2 similar studies conducted 12 and 24 years earlier. METHODS: In April 2010, 500 surveys were distributed to English-speaking trekkers at 3500 m on their way to 5400 m, of which 332 (66%) surveys were returned complete. Acute mountain sickness was quantified with the Lake Louise Scoring System (LLSS, cutoff ≥3 and ≥5) and the Environmental Statistical Questionnaire III AMS-C score (ESQ-III, cutoff ≥0.7). We surveyed demographics, body mass index (BMI), smoking habit, rate of ascent, awareness of AMS, and acetazolamide use. RESULTS: Prevalence of AMS was 22%, 23%, and 48% (ESQ-III ≥0.7, LLSS ≥5, and LLSS ≥3, respectively) lower when compared with earlier studies. Risk factors for AMS were younger age, female sex, higher BMI, and smoking habit. Forty-two percent had elementary knowledge about the risk and prevention of AMS. Forty-four percent used acetazolamide. Trekkers took longer to climb from 3500 to 5400 m than in earlier studies. CONCLUSIONS: Prevalence of AMS continued to decline over a period of 24 years, likely as a result of slower ascent and increased use of acetazolamide. The AMS risk factors of younger age, female sex, and high BMI are consistent with prior studies. Awareness of risk and prevention of AMS remains low, indicating an opportunity to better educate trekkers and potentially further reduce AMS prevalence.

Outbreak of Rocky Mountain spotted fever in Córdoba, Colombia

Rocky Mountain spotted fever (RMSF) is a tick-borne disease caused by the obligate intracellular bacterium Rickettsia rickettsii. Although RMSF was first reported in Colombia in 1937, it remains a neglected disease. Herein, we describe the investigation of a large cluster of cases of spotted fever rickettsiosis in a new area of Colombia.

Stable carbon isotope composition of perirenal adipose tissue fatty acids from Engadine sheep grazing either mountain or lowland pasture

To provide further insights into ruminant lipid digestion and metabolism, and into cis9, trans-11 18:2 synthesis, 12 growing Engadine lambs grazing either mountain pasture (2,250 m above sea level; n = 6) or lowland pasture (400 m above sea level; n = 6) were studied. Both pastures consisted exclusively of C-3 plants. Before the experiment, all animals grazed a common pasture for 6 wk. Grasses and perirenal adipose tissues of the sheep were analyzed for fatty acids by gas chromatography. Stable C-isotope ratios (delta C-13 values in % vs. the Vienna Pee Dee Belemnite standard) were determined in the composite samples by elemental analysis-isotope ratio mass spectrometry. The delta C-13 of the individual fatty acids were measured by gas chromatography-combustion-isotope ratio mass spectrometry. The delta C-13 value of the entire mountain pasture grass was -27.5% (SD 0.31), whereas that of the lowland pasture grass was -30.0% (SD 0.07). This difference was reflected in the perirenal adipose tissues of the corresponding sheep (P < 0.05), even though the delta C-13 values were less in the animals than in the grass. The delta C-13 values for cis-9 16:1 and cis-9 18:1 in perirenal fat differed between mountain and lowland lambs (P < 0.05). The 16:0 in the adipose tissue was enriched in C-13 by 5% compared with the dietary 16:0, likely as a result of partly endogenous synthesis. The d13C values of cis-9, trans-11 18:2 (cis-9, trans-11 CLA) in the adipose tissue were smaller than those of its dietary precursors, cis-9, cis-12 18:2 and cis-9, cis-12, cis-15 18:3; conversely, the delta C-13 values of trans-11 18:1 were not, suggesting that large proportions of perirenal cis-9, trans-11 18:2 were of endogenous origin and discrimination against C-13 occurred during Delta(9)-desaturation. The same discrimination was indicated by the isotopic shift between 16:0 and cis-9 16:1 in the mountain grazing group. Furthermore, the delta C-13 values of cis-9, trans-11 18:2 were smaller relative to the precursor fatty acids in the mountain lambs compared with the lowland group. This result suggests a reduced extent of biohydrogenation in lambs grazing on mountain grass in comparison with those grazing on lowland grass. This was supported by the smaller cis-9, trans-11 18:2 concentrations in total fatty acids found in the adipose tissues of the lowland lambs (P < 0.001). The results of this study demonstrate that natural differences between delta C-13 values of swards from different pastures and the adipose tissue fatty acids could be used as tracers in studies of lipid metabolism in ruminants.

Land use improves spatial predictions of mountain plant abundance but not presence-absence

Question Does a land-use variable improve spatial predictions of plant species presence-absence and abundance models at the regional scale in a mountain landscape? Location Western Swiss Alps. Methods Presence-absence generalized linear models (GLM) and abundance ordinal logistic regression models (LRM) were fitted to data on 78 mountain plant species, with topo-climatic and/or land-use variables available at a 25-m resolution. The additional contribution of land use when added to topo-climatic models was evaluated by: (1) assessing the changes in model fit and (2) predictive power, (3) partitioning the deviance respectively explained by the topo-climatic variables and the land-use variable through variation partitioning, and (5) comparing spatial projections. Results Land use significantly improved the fit of presence-absence models but not their predictive power. In contrast, land use significantly improved both the fit and predictive power of abundance models. Variation partitioning also showed that the individual contribution of land use to the deviance explained by presence-absence models was, on average, weak for both GLM and LRM (3.7% and 4.5%, respectively), but changes in spatial projections could nevertheless be important for some species. Conclusions In this mountain area and at our regional scale, land use is important for predicting abundance, but not presence-absence. The importance of adding land-use information depends on the species considered. Even without a marked effect on model fit and predictive performance, adding land use can affect spatial projections of both presence-absence and abundance models.

Modelling changes in stable isotope compositions of minerals during net transfer reactions in a contact aureole: Wollastonite growth at the northern Hunter Mountain Batholith (Death Valley National Park, USA)

One of the world's largest wollastonite deposits was formed at the contact of the northern Hunter Mountain Batholith (California, USA) in Paleozoic sediments. Wollastonite occurs as zones of variable thickness surrounding layers or nodules of quartzite in limestones. A minimum formation temperature of 650 degrees C is estimated from isolated periclase-bearing lenses in that area. Contact metamorphism of siliceous carbonates has produced mineral assemblages that are consistent with heterogeneous, and partly limited infiltration of water-rich fluids, compatible with O-18/O-16 and C-13/C-12 isotopic patterns recorded in carbonates. Oxygen isotope compositions of wollastonites in the study area may also not require infiltration of large quantities of externally-derived fluids that were out of equilibrium with the rocks. 8180 values of wollastonite are high (14.8 parts per thousand to 25.0 parts per thousand; median: 19.7 parts per thousand) and close to those of the host limestone (19.7 parts per thousand to 28 parts per thousand; median: 24.9 parts per thousand) and quartz (18.0 parts per thousand. to 29.1 parts per thousand; median: 22.6 parts per thousand). Isotopic disequilibrium exists at quartz/wollastonite and wollastonite/calcite boundaries. Therefore, classical batch/Rayleigh fractionation models based on reactant and product equilibrium are not applicable to the wollastonite rims. An approach that relies on local instantaneous mass balance for the reactants, based on the wollastonite-forming reaction is suggested as an alternative way to model wollastonite reaction rims. This model reproduces many of the measured delta O-18 values of wollastonite reaction rims of the current study to within +/- 1 parts per thousand, even though the wollastonite compositions vary by almost 10 parts per thousand. (C) 2011 Elsevier B.V. All rights reserved.

Gene duplication, population genomics, and species-level differentiation within a tropical mountain shrub.

Gene duplication leads to paralogy, which complicates the de novo assembly of genotyping-by-sequencing (GBS) data. The issue of paralogous genes is exacerbated in plants, because they are particularly prone to gene duplication events. Paralogs are normally filtered from GBS data before undertaking population genomics or phylogenetic analyses. However, gene duplication plays an important role in the functional diversification of genes and it can also lead to the formation of postzygotic barriers. Using populations and closely related species of a tropical mountain shrub, we examine 1) the genomic differentiation produced by putative orthologs, and 2) the distribution of recent gene duplication among lineages and geography. We find high differentiation among populations from isolated mountain peaks and species-level differentiation within what is morphologically described as a single species. The inferred distribution of paralogs among populations is congruent with taxonomy and shows that GBS could be used to examine recent gene duplication as a source of genomic differentiation of nonmodel species.

Reproducibility of acute mountain sickness in children and adults : a prospective study

Objectif: Alors qu'un antécédent d' AMS est couramment utilisé pour fournir des conseils et recommander une prophylaxie médicamenteuse pour les expositions ultérieures à la haute altitude, la reproductibilité intra-individuelle de l'AMS au cours d'expositions répétées n'a jamais été examinée dans une étude prospective contrôlée. Méthodes : Chez 27 enfants et 29 adultes non acclimatés, nous avons évalué la présence et la sévérité de l' AMS durant les 48 premières heures après une montée rapide à 3450m, et ceci en deux occasions distantes de 9 à 12 mois. Résultats: 18 adultes (62 %) et 6 enfants (22 %) ont souffert d'AMS durant la première exposition et 14 adultes (48 %) et 4 enfants (15 %) durant la seconde (P=O.Ol, adultes versus enfants). Mais surtout, la reproductibilité intra-individuelle de l'AMS était très différente (P < 0.001) entre les deux groupes; en effet, aucun des 6 enfants ayant souffert d'AMS au cours de la première exposition n'en n'a souffert au cours de la seconde mais 4 enfants sans AMS lors de la première exposition ont été touchés lors de la seconde exposition. Contrairement à cela, 14 des 18 adultes qui ont souffert de 1' AMS lors de la première exposition ont également présenté ce problème au cours de la seconde et aucun nouveau cas ne s'est développé dans ceux qui n'avaient pas souffert de cette affection lors de la première occasion. ConClusion : Si chez 1' adulte, un antécédent d' AMS a une bonne valeur prédictive d'un nouvel épisode durant les expositions futures dans des conditions similaires, il n'en est pas de même chez l'enfant chez lequel il n'a pas de valeur prédictive. Un antécédent d'AMS ne devrait donc pas inciter les praticiens à déconseiller la réexposition ou à prescrire une prophylaxie médicamenteuse chez l'enfant.

Modeling the biophysical impacts of global change in mountain biosphere reserves

Mountains and mountain societies provide a wide range of goods and services to humanity, but they are particularly sensitive to the effects of global environmental change. Thus, the definition of appropriate management regimes that maintain the multiple functions of mountain regions in a time of greatly changing climatic, economic, and societal drivers constitutes a significant challenge. Management decisions must be based on a sound understanding of the future dynamics of these systems. The present article reviews the elements required for an integrated effort to project the impacts of global change on mountain regions, and recommends tools that can be used at 3 scientific levels (essential, improved, and optimum). The proposed strategy is evaluated with respect to UNESCO's network of Mountain Biosphere Reserves (MBRs), with the intention of implementing it in other mountain regions as well. First, methods for generating scenarios of key drivers of global change are reviewed, including land use/land cover and climate change. This is followed by a brief review of the models available for projecting the impacts of these scenarios on (1) cryospheric systems, (2) ecosystem structure and diversity, and (3) ecosystem functions such as carbon and water relations. Finally, the cross-cutting role of remote sensing techniques is evaluated with respect to both monitoring and modeling efforts. We conclude that a broad range of techniques is available for both scenario generation and impact assessments, many of which can be implemented without much capacity building across many or even most MBRs. However, to foster implementation of the proposed strategy, further efforts are required to establish partnerships between scientists and resource managers in mountain areas.