Download or read book A Quantitative Geomorphic Approach to Predicting Productivity of Pink and Chum Salmon Streams in Southeast Alaska written by Douglas N. Swanston and published by . This book was released on 1977 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Quantitative Geomorphic Approach to Predicting Productivity of Pink and Chum Salmon Streams in Southeast Alaska Classic Reprint written by Douglas N. Swanston and published by Forgotten Books. This book was released on 2018-09-07 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from A Quantitative Geomorphic Approach to Predicting Productivity of Pink and Chum Salmon Streams in Southeast Alaska Thompson and Hunt (1930) stressed the importance of the drainage basin as a whole, not just the stream, in their investigations of the basic nature of stream productivity. Slack (1955) reinforced this concept in his studies of stream productivity factors, demonstrating that the biolog ical productivity of a stream is directly related to the physical environment of the watershed, which controls drainage pattern, flow rates, gravel size and shape, channel gradient, and general stability characteristics. Statistical analysis of quantitative geomorphic parameters of individual watersheds can help identify these factors. Quantitative geomorphic techniques developed by Horton (1932, 1945) and Strahler (1952, 1953, 1954) provide a convenient method for obtaining numerical data on gross basin character istics, given limited funding and difficulty of access and sampling of test streams. Measurement of physical parame ters based on basin and channel geometry, obtainable from aerial photographs and topographic maps, provides correlation units such as drainage size and shape, stream density, and pattern, number, and length of tribu taries. These in turn provide an estimate of stage of water shed development, probable basin discharge, extent of bedrock control of drainage, impact of unstable slopes, and extent of channel suitable for spawning. Such techniques have been used successfully to analyze relationships between erosion, climate, surface properties, and geomorphology (melton 1957, Maxwell 1960, Dissmeyer In 1973, Ziemer used quantitative geomorphic techniques to relate drainage basin and channel configuration to changes in production of pink salmon on Montague Island Prince William Sound, Alaska, after large vertical tectonic adjustments resulting from the Good Friday Earthquake of 1964. Using five drainage system factors, he showed a correlation between drainage system geometry and freshwater production factors for pink salmon, with escapement as his indicator of production. He assumed that (1) the number of spawners using a stream is a sound measure of fish production in that stream, (2) escapement counts were consistently made from year to year and stream to stream, and (3) the impact of the fishery was consistent between stocks and years. He realized the problems involved by making these assumptions, but he had no other tools available. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Download or read book A Quantitative Geomorphic Approach to Predicting Productivity of Pink and Chum Salmon Streams in Southeast Alaska written by Douglas N. Swanston and published by . This book was released on 1977 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Quantitative Geomorphic Approach to Predicting Productivity of Pink and Chum Salmon Streams in Southeast Alaska written by Douglas N. Swanston and published by . This book was released on 1977 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Research Paper PNW written by Arthur R. Tiedemann and published by . This book was released on 1977 with total page 730 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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Download or read book Monthly Catalog of United States Government Publications written by United States. Superintendent of Documents and published by . This book was released on 1978 with total page 1228 pages. Available in PDF, EPUB and Kindle. Book excerpt: February issue includes Appendix entitled Directory of United States Government periodicals and subscription publications; September issue includes List of depository libraries; June and December issues include semiannual index

Download or read book Monthly Catalogue United States Public Documents written by and published by . This book was released on 1978 with total page 832 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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Download or read book Models that Predict Standing Crop of Stream Fish from Habitat Variables written by Kurt D. Fausch and published by . This book was released on 1988 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt: We reviewed mathematical models that predict standing crop of stream fish (number or biomass per unit area or length of stream) from measurable habitat variables and classified them by the types of independent habitat variables found significant, by mathematical structure, and by model quality. Habitat variables were of three types and were measured on different scales in relation to stream channels: variables of drainage basins were measured on the coarsest scale from topographic maps; channel-morphometry and flow variables were measured in the field along transects perpendicular to flow; and habitat-structure, biological, physical, and chemical variables were measured on the finest scale in the field. We grouped the 99 reviewed models by the types of independent variables found significant during model development: (A) primarily drainage basin (5 models), (8) primarily channel morphometry and flow (16 models), (C) primarily habitat structure, biological, physical, and chemical (25 models), (D) a combination of several types of variables (39 models), and (E) tests of weighted usable area as a habitat model (14 models. Most models were linear or multiple linear regressions, or correlations, but a few were curvilinear functions (exponential or power). Some used multivariate techniques (principal components or factor analysis), and some combined independent variables into one or more indices. We judged model quality based on simple criteria of precision and generality: coefficient of determination, sample size, and degrees of freedom. Most models were based on data sets of fewer than 20 observations and, thus, also had fewer than 20 degrees of freedom. Most models with coefficients of determination of greater than 0.75 had fewer than 20 degrees of freedom, which led us to conclude that relatively precise models often lacked generality. We found that sound statistical procedures were often overlooked or were minimized during development of many models. Frequent problems were too small a sample size, possible bias caused by error in measuring habitat variables, using poor methods for choosing the best model, not testing models, using models based on observational data to predict standing crop, and making unrealistic assumptions about capture probabilities when estimating standing crop. The major biological assumptionthat the fish population was limited by habitat rather than fishing mortality, interspecific competition, or predationusually was not addressed. We found five main ways stream-fish-habitat models are used in fishery management. To be useful for analyzing land management alternatives, models must include variables affected by management and be specific for a homogeneous area of land.

Download or read book Statistical Ecology written by John A. Ludwig and published by John Wiley & Sons. This book was released on 1988-05-18 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ecological community data. Spatial pattern analysis. Species-abundance relations. Species affinity. Community classification. Community ordination. Community interpretation.