No description available.

The purpose of this study is to 1: Get an updated population estimate for the regionally endangered alpine specialist plant Phippsia concinna in Sweden and 2: Explore the ecological dependencies that limits the distributions of this species to late melt-out alpine snowbeds on calcareous soils, and 3: Explore if climate change in the southern part of the Scandes mountain range is causing a decline in the population numbers of P. concinna. The majority of the sites in Sweden where P. concinna occurred historically was inventoried in 1992. This study presents the results of a re-inventory of the same snowbeds after 22 years, along with measurements of abiotic soil factors and records of abundance and composition of associated vegetation at the sites. The main findings are 1: Population number of P. concinna has increased but one third of the original populations has disappeared since 1992, and 2: Soil pH appears to limit the distributions of P. concinna while slope aspect and soil Nitrogen concentrations affects this species competitive abilities in the Swedish Scandes. 3: Presence of P. concinna is negatively correlated to cover of other graminoids and bryophytes. These results suggests that snowbeds are melting earlier following increased temperatures and precipitations in summer, resulting in longer vegetation periods that favours plant species with stronger competitive abilities over specialised snowbed species. The observed rate of change in P. concinna populations during 22 years is evidence of fast occurring vegetation changes and highlights the need to monitor rare plant species in alpine environments.

Syftet med detta arbete är att ta fram den ultimata träkärnan utefter uppspaltade önskemål på egenskaper i ett par allmountainskidor med nordiska träslag. Studien är deskriptiv och kvantitativ då den syftar till att mäta förändringsgraden under påverkan på träslagen. För att få in data till mina frågeställningar har tester genomförts som genererar datainsamling. En förundersökning gjordes med intervjuer för att få fram ett mer specificerat underlag för att konstruera vilken metod jag skulle ha i det slutgiltiga arbetet. Resultatet av studien visade att träslaget bok hade de bästa egenskaperna vad gäller böjhållfasthet. Ask hade de bästa egenskaperna när det kom till testerna på vridstyvhet. Det negativa med dessa träslag är att de är för tunga. Det lättaste träslaget av de som var med i testerna var poppel. Därför har jag valt att i den slutgiltiga träkärnan kombinera träslag. Två olika förslag har tagits fram. Den ena med en kombination av bok och poppel, den andra med ask och poppel. Den första ger en förhållandevis lätt skida med bra böjhållfasthet. Den andra en lätt skida med bra vridstyvhet. Dessa två träkärnor kommer användas i byggandet av mina skidor och testas på berget. / The purpose of this work is to produce the most optimal wood core with the desired requirements in an all-mountain ski using Scandinavian wood. The study is descriptive and quantitative as it aims to measure the rate of change under the influence of wood species. In order to collect data for my research questions, tests have been carried out which generate data collection. A preliminary investigation was done with interviews to obtain a more detailed basis for constructing the method I would use in the final work. The results of the study showed that the wood type beech had the best results in terms of flexural strength. Ash had the best results when it came to tests on torsional rigidity. The down side of these woods is that they are too heavy. The lightest wood species of those involved in the tests was poplar. Therefore, I have chosen to combine species in the final wood core. Two different suggestions have been developed. One with a combination of beech and poplar, the other one with ash and poplar. The first provides a relatively light ski with good flexural strength. The second produced a light ski with good torsional rigidity. These two wood cores will be used in the construction of my skis and tested on the mountain.

This research established long-term alpine monitoring in southwestern British Columbia by following the protocol outlined in the Global Observation Research Initiative in Alpine environments (GLORIA). The aim of this international project is to establish a long-term observation network to obtain standardized data on alpine biodiversity, vegetation patterns and temperature on a global scale. Research plots (known as target regions) were established in the Mount Arrowsmith region on Vancouver Island and in the Whistler region. A target region is comprised of four summits that each represent an altitudinal gradient of vegetation patterns characteristic for the respective mountain regions. The GLORIA protocol focuses on capturing changes in: species richness (number of species), species composition (loss or gain of individual species), patterns of vegetation (changes in % cover), soil temperatures of microhabitats, and snow cover. The analysis of data presented in this thesis related environmental characters (area, slope, elevation, aspect and top cover) and species characters to species richness and composition. This research indicates that overall in the Arrowsmith and Whistler target regions, species richness was consistently greater in larger study plots and in plots where the cover of vascular plant species was relatively high. Elevation alone, sometimes seen as an indirect measure of temperature did not seem to play a significant role in predicting species richness. All species inventoried were ‘as expected’. All of these observations made sense ecologically, are in line with current hypotheses, and demonstrate that the summits chosen in the Arrowsmith and Whistler target regions are typical alpine areas and suitable for long-term study. / Graduate

Several lines of evidence suggest small alpine lakes and ponds are sensitive to nitrogen deposition. Paleolimnological studies, nutrient bioassays, and mesocosm experiments show the positive effects of nitrogen on aquatic alpine primary producers. In particular, alpine pond ecosystems have been inferred to be nitrogen-limited based on low availability of dissolved inorganic nitrogen relative to total phosphorus. However, nitrogen-limitation of alpine ponds has never been tested at the whole-ecosystem level. I performed a replicated in situ whole-pond experiment, consisting of two crossed treatments (2 nitrogen x 2 phosphorus levels) applied across 16 natural alpine ponds (n = 4) immediately following ice-out in 2008. Surprisingly, neither nutrient amendment stimulated phytoplankton or zooplankton abundance although subtle shifts in community composition were detected over a two-month period. Intensive grazing pressure exerted by high densities (> 100 individuals/ m2) of herbivorous Branchinecta paludosa (fairy shrimp) may have suppressed planktonic responses to nutrient additions. Another ecological explanation for the lack of a positive effect of nutrients on phytoplankton abundance was competition from periphyton, which are comparatively more abundant in most shallow ponds on an areal basis. Therefore, density-dependent ecological interactions (competition and predation) may mediate the responses of phytoplankton to nitrogen deposition over ponds situated in extreme environments. / Ecology

Mountain precipitation, as a major component of global ecology and culture, requires diverse observation-based distribution studies to improve process characterisation and so enhance environmental management and understanding. Analysis of data from an array of precipitation gauges within the nationally important, and internationally extreme, mountainous Lake Pukaki catchment in New Zealand has been undertaken in an effort to provide such a study, while also improving local hydrological understanding. An objective observation based undercatch-corrected 1971-2000 average annual precipitation distribution has been prepared for the mountainous Lake Pukaki catchment, New Zealand. Precipitation records from 58 gauges at 51 sites, augmented with 10 new gauges, were used in preparation of the distribution. The assessed undercatch correction of 17 % across the catchment indicates that mountain hydrological investigations in New Zealand that use precipitation data and yet do not consider undercatch will be in considerable error. The average annual distribution confirms the existence of high precipitation magnitudes and horizontal gradients in the catchment in comparison with other mountain regions around the world. The high magnitude is unusual when its position in the lee of the principal orographic divide is considered indicating rare precipitation distribution processes occur in the region. Consideration of river flows, glacial change and evaporation led to a confirmation of the gauge derived average catchment precipitation. Precipitation to wind direction relationships identified the predominant westerly wind to be the primary precipitation generating direction with large magnitude events biased towards the northerly direction. All directions from the eastern side of the mountain divide had the lowest frequency and daily precipitation magnitude. Derivation of wind-classed precipitation distributions identified a distinctive south east to north west precipitation gradient for all wind directions, most severe for the north west direction and least severe for the easterly direction. Precipitation extent was greatest for the northerly direction and least for the south south westerly. The wind-classed distributions enable the estimation of daily precipitation likelihood and magnitude at any location in the catchment based on knowledge of the synoptic wind flow direction and precipitation at just one reference site. Improved river flow and lake inflow estimates resulted from the use of wind classed daily precipitation estimates validating the quality of the wind classed distributions. From 1939 to 2000 there has been no statistically significant trend in precipitation magnitudes, frequencies, or extremes in the catchment. At Aoraki/Mt Cook village, in the upper catchment, there have been significant increases in magnitude, frequency and extremes associated with the phase change of the Interdecadal Pacific Oscillation (IPO) in 1978. This change can be explained by the increase in strength of westerly winds for the different IPO phases but not by a change in frequency of different wind directions. In the lower catchment the IPO relationship is of an opposite sense to that observed in the upper catchment, indicating that the areas operate under two different climate regimes with different precipitation controls. The significant relationship to the IPO phase indicates that it is more important than climate warming in terms of future precipitation distribution in the Lake Pukaki catchment, and by extension the Southern Alps. The distributions prepared provide a valuable tool for operational and academic hydrological applications in the region. In addition, they provide a valuable characterisation of the precipitation in a Southern Hemisphere mid-latitude lee to predominant westerlies glacierized mountain catchment. From this standpoint they highlight the contrast to Northern Hemisphere mountain precipitation distributions commonly used in model validation studies, thereby providing an extension of locations with which to refine orographic precipitation process understanding.

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves 108-112). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1996. / Typescript. Vita. Includes bibliographical references (leaves 108-112). Also available on the Internet.

No description available.

Alpine treeline ecotones (ATE) are the transition zones between contiguous subalpine forest and open alpine tundra. Because of their transitional natures formed by different ecosystems in high mountain areas, there are a variety of acute interactions between different species, between vegetations and environmental factors, and between ecological pattern and process. These interactions, or feedbacks, are often nonlinear in nature and make alpine treeline ecotones sensitive to environmental change, especially climate change. Feedbacks or nonlinear interactions between pattern and process create a variety of distinctive yet sometime surprising alpine treeline patterns. These nonlinear interactions between pattern and process and their resultant various patterns are defined as spatial complexity. In this study, the research framework of complexity theory was adopted. Dynamical simulations of alpine treeline ecotone is used as basic research method, and local nonlinear interactions, or more specifically, positive feedbacks are considered the key mechanism driving alpine treeline dynamics. A cellular simulation was created with tree/no-tree states that change as a function of probabilities of tree establishment and mortality which are functions of the neighborhood and an underlying gradient; the former changes in space and time endogenously; the latter can change in space and time exogenously. Three research projects were conducted for this dissertation that explore the endogenous and exogenous aspects of alpine treeline dynamics. First, the endogenous dynamics of alpine treeline ecotones was examined, which indicates that local positive feedbacks originated from interactions between trees can create fractal spatial dynamics in space and time. Second, the impacts of geomorphologic factors that impose an exogenous spatial structure on alpine treeline dynamics, was examined, which shows that there is a geomorphic limit to the endogenous fractal alpine treeline dynamics. Third, the impacts of climate change that imposes an exogenous temporal structure on alpine treeline dynamics was examined, which suggests that the self-organization nature of alpine treeline dynamics will not be significantly affected by external climate change and the use of alpine treeline ecotones as potential indicator of climate change is called into question. Results of this study suggest further research using complexity theory is needed to improve our understanding of alpine treeline dynamics and their interactions with exogenous environmental factors.