10,031 research outputs found

    An Ecological Study of Timberline and Alpine Areas, Mount Lincoln, Park County, Colorado

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    During the short alpine growing season of 1945 the authors had the opportunity of studying conditions and biota on Mount Lincoln, Park County, Colorado, in an attempt to evaluate the ecological conditions and animal communities of the area. Of the large amount of taxonomic and ecological zoology published on the state, most has been in the field of autecology, and, except in the province of aquatic studies, little has appeared bearing on synecological relations, especially among invertebrates. The marked differences between the physiography, climatology, and biology of timberline, alpine, and other stations seemed to offer a field well worthy of investigation. Since the work was done, other factors have been introduced which have greatly altered the nearly primitive conditions encountered at the time of the investigation. One of the areas has been entirely destroyed by the formation of a water storage lake, and others have been affected through heavy summer grazing by bands of sheep. The material published on the Mount Lincoln area is very limited. Cary (1911) was concerned with similar areas in other parts of the state, but apparently he did not work around the mountains at the head of the South Platte. The most detailed paper on the region is that of Patton and his collaborators (1912) which covers the physiography very completely. There are scattered references to the animal life of the vicinity in Coues (1874), Sclater (1912), Warren (1942), and elsewhere. The most complete published reports on the animal life of the region are those of Brewer (1871) and Allen (1872, 1876a, 1876b); the first of Allen\u27s papers is the source of most of Coues\u27 references to the Mount Lincoln avifauna. None of these papers deals with the invertebrates, save for comments by Brewer on the relative abundance of certain orders of insects

    Present and past geocryogenic processes in Mexico: A synopsis

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    Is the Sun a Long Period Variable

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    The inventory of atmospheric radiocarbon exhibits quasi-periodic variations of mean period of bar-lambda=269 years over the entire 9000 year record. But the period is inconstant and subject to random variability (sigma m exp. 1/2 = 119 years). The radiocarbon maxima correspond to the quasiperiodic extension of the Maunder minimum throughout the Holocene and resolve the long-standing issue of Maunder cyclicity. The radiocarbon maxima are amplitude modulated by the approx. 2300 year period and thus vary significantly in peak value. The approx. 2300 year period in turn appears to not be modulated by the secular geomagnetic variation. Detection of a Maunder-like sequence of minima in tree ring growth of Bristlecone pine and its correlation with the Maunder (1890, 1922) cyclicity in the radiocarbon record supports the inference that solar forcing of the radiocarbon record is accompanied by a corresponding forcing of growth of timberline Bristlecone pine. Because of the random component of the Maunder period, prediction of climate, if tied to the Maunder cycle other than probabilistically, is significantly hindered. For the mean Maunder period of 269 years, the probability is 67 percent that a given climatic maximum lies anywhere between 150 and 388 years

    Revegetation Research on Coal Mine Overburden Materials in Interior to Southcentral Alaska

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    This report was reprinted from Focus on Alaska's Coal '86: Proceedings of the Conference MIRL Report Number 72. The pagination in the original publication has been retained. Focus on Alaska's Coal '86 was published in July 1987 by Mineral Industry Research Laboratory, University of Alaska Fairbanks, Fairbanks, Alaska 99775-1180.Plant material, and planting and fertilizer scheduling studies were conducted on coal mine overburden materials in the Nenana coal field at the Usibelli coal mine near Healy, in the Matanuska coal field at the Jonesville mine north of Anchorage, and at two test pits in the Beluga coal field west of Anchorage. With proper fertilization a number of grasses were found to maintain adequate cover for soil stabilization purposes over the five-to-seven-years of the various trials. The consistently good performers were entries of tufted hairgrass, Bering hairgrass, red fescue, hard fescue polar-grass, and Kentucky bluegrass. Most were native to Alaska. Some northern -selected materials of alfalfa did well on sites below timberline with near neutral soils. Fertilizer responses and indicated nutrient requirements indicated a preferred schedule of fertilizer applications in the first and third, and possibly fifth or sixth growing years. Seedings conducted from spring, in late May, into summer, in late July, produced equally satisfactory results

    Floristics of the South American Páramo moss flora

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    The South American paramos appeared in Pliocene times and persist to the present day. The moss flora of this habitat consists of an estimated 400 species that comprise 8 floristic groups. In Venezuela these groups and their percent representation are as follows: neotropical 37%, Andean 26%, cosmopolitan 18%, Andean-African 8%, neotropical-Asiatic 3%, neotropical-Australasian 2%, temperate Southern Hemisphere 2% and northern boreal-temperate 2%. Acrocarpous taxa outnumber pleurocarps by nearly 3:1. The neotropical and Andean floristic stocks likely were present prior to late Pliocene orogenies that elevated the cordillera above climatic timberlines. These species may have existed in open, marshy areas (paramillos) or may have evolved from cloud forest ancestors. Taxa of northern boreal- temperate affinities, including those with Asiatic distributions, probably arrived in the paramos during the Pleistocene, a period which may also have seen the establishment in the Northern Andes of some cosmopolitan elements. Species with temperate Southern Hemisphere and Australasian affinities likely spread first to austral South America thence migrated northward during a cool, moist interval sometime over the past 2.5-3 million years or may have become established in the paramos as a result of long- distance dispersal

    Spider (Arachnida: Araneae) distribution across the timberline in the Swiss Central Alps (Alp Flix, Grisons) and three morphologically remarkable species

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    We collected 6251 adult epigeic spiders from the dwarf-shrub heath to subalpine coniferous forest on Alp Flix (CH, canton Grisons, 1950 m) between May 2005 and May 2006 using pitfall traps. Total species richness and activity density of all species decreased from the open land to the forest, although this pattern varied according to family. The distribution of the 102 species found indicates that the small area around a single tree at the timberline provides habitats for both open land and forest spider species as well as some possible timberline specialists. Five species were new to the canton Grisons: Centromerita bicolor, Centromerita concinna, Hilaira excisa, Meioneta alpica and Tallusia experta. Three species showed remarkable morphological characteristics and were analysed in more detail. We found males of Pelecopsis radicicola without the characteristic longitudinal depression on the raised carapace. It is shown that the males of Meioneta alpica have a considerably variable lamella characteristica, which is nevertheless distinct from the sister species Meioneta ressli. Because we found intermediate forms of the head region described for Metopobactrus prominulus and M. schenkeli, respectively, M. schenkeli is considered a syn. nov. of M. prominulus. This study shows that the known distribution and taxonomic status of various spider taxa in the Central Alps are still incomplete and further work on arthropods in remote areas should be strongly encouraged

    Of beta diversity, variance, evenness, and dissimilarity

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    The amount of variation in species composition among sampling units or beta diversity has become a primary tool for connecting the spatial structure of species assemblages to ecological processes. Many different measures of beta diversity have been developed. Among them, the total variance in the community composition matrix has been proposed as a single-number estimate of beta diversity. In this study, I first show that this measure summarizes the compositional variation among sampling units after nonlinear transformation of species abundances. Therefore, it is not always adequate for estimating beta diversity. Next, I propose an alternative approach for calculating beta diversity in which variance is substituted by a weighted measure of concentration (i.e., an inverse measure of evenness). The relationship between this new measure of beta diversity and so-called multiple-site dissimilarity measures is also discussed

    Alpine Timberlines in the Americas and Their Interpretation

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    The literature of plant geography has long contained references to the facts that (1) in progressing from the poles toward the equator, alpine timberline increases in elevation above sea level, and that (2) the elevation of this timberline exhibits considerable variation at any one latitude on different mountain systems. More recently a third fact concerning the geography of this vegetation boundary has been documented; the latitude-altitude relationship is not rectilinear

    2006 International Pinot Noir Celebration Program

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    This document is the 2006 program for the International Pinot Noir Celebration (IPNC), held annually on the campus of Linfield College in McMinnville, Oregon. The program contains a detailed schedule of the celebration’s major events, presentations, and meals, as well as information regarding guest speakers, chefs, and artists visiting the campus. The program also includes a short description of all participating wineries for 2006, both foreign and domestic, along with a listing of the IPNC board of directors and all major supporters and contributors to the event

    Can Forest Management Strategies Sustain The Development Needs Of The Little Red River Cree First Nation?

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    In this study, we explore whether projected socio-economic needs of the Little Red River Cree Nation (LRRCN) can be met using the natural resources to which they have access. To answer this question, we employ a dynamic optimization model to assess the capacity of the available forest base to provide for anticipated future needs of the LRRCN. Results for alternative management strategies indicate that decision-makers face significant tradeoffs in deciding an appropriate management strategy for the forestlands they control.boreal forest, First Nations, forest management, sustainability
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