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Journal ArticleDOI

Two basic methodological choices in wildland vegetation inventories: their consequences and implications

01 Apr 1982-Journal of Applied Ecology-Vol. 19, Iss: 1, pp 249-262
TL;DR: Two Basic Methodological Choices in Wildland Vegetation Inventories: Their Consequences and Implications are illustrated.
Abstract: Two Basic Methodological Choices in Wildland Vegetation Inventories: Their Consequences and Implications

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Utah State University Utah State University
DigitalCommons@USU DigitalCommons@USU
All Graduate Theses and Dissertations Graduate Studies
5-1979
Two Basic Methodological Choices in Wildland Vegetation Two Basic Methodological Choices in Wildland Vegetation
Inventories: Their Consequences and Implications Inventories: Their Consequences and Implications
Donald Alan Shute
Utah State University
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Recommended Citation Recommended Citation
Shute, Donald Alan, "Two Basic Methodological Choices in Wildland Vegetation Inventories: Their
Consequences and Implications" (1979).
All Graduate Theses and Dissertations
. 6347.
https://digitalcommons.usu.edu/etd/6347
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ACKNOWLEDGMENTS.
LIST OF TABLES .
LIST OF FIGURES.
ABSTRACT ..
INTRODUCTION
METHODS ...
Scope of study
Study area . .
Study design.
TABLE OF CONTENTS
Data collection, reduction, and analysis
RESULTS ..
Using vegetation X's to predict production
Comparison of regression models including
vegetation, soil, and environmental data.
DISCUSSION AND IMPLICATIONS FOR VEGETATION INVENTORY
REFERENCES
. . . . . . . . . . . . . . . . . . .
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Table
1.
LIST OF TABLES
Subsets of variables in vegetation-environment
regression models .....••....•...
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Citations
More filters
01 Jan 1986
TL;DR: In this article, a radio-tracked group of 13 badgers and 20 foxes living in Wytham Estate, Oxfordshire, between 1981 and 1983 was identified from bait marking and radio-tracking.
Abstract: Thirteen badgers and 20 foxes were radio-tracked in the Wytham Estate, Oxfordshire, between 1981 and 1983. Thirteen badger and 10 fox groups were identified from radio-tracking and bait marking. Badger groups (mean size 1982: 4.45, 1983: 5.82) occupied contiguous territories (size: 22-75 ha) with boundaries marked by latrines. Seasonal variation in marking intensity and choice of marking sites presumably were responses to changing intrusion pressure. Fox groups (mean size: 2.6) occupied stable territories (size: 22- 104 ha) with little overlap. Faeces deposition by foxes facilitated territory marking. Earthworms (Lumbricus terrestris) dominated the diet of badgers (63 % estimated dry weight EDW, faeces), followed by cereals, fruits and other Invertebrates. Diet was highly variable between groups and seasons. For foxes, lagomorphs (20 % EDW) and earthworms (33 % EDW) were the most important prey, followed by scavenge and fruits. Variation in diet between groups and seasons was marked in lagomorphs but not earthworms. Multlvarlate analyses of habitat parameters revealed a low-dimensional 'resource space' that could be divided into conventional habitat categories. Censuses of prey species indicated that resource presence varied consistently between habitat categories. Key habitats occurred at fairly constant proportions in territories of both species) their dispersion partly determined the configuration of territory boundaries. The proportions of specific habitats per territory were correlated with the proportions of certain prey items in diets. space use by individuals was analysed by spatial autocorrelation methods, variation in space use by foxes was attributed to variation in resource dispersion. In contrast, individual badgers were similar in their use of space. Here, small-scale heterogeneity in intensity of use may reflect local earthworm availability, in one studied fox group, males and females differed in range use. Individuals in one studied badger group coordinated their use of space probably to minimize foraging interference. It is suggested that group living in Wytham badgers is a response to defending resources, and a model is proposed to explain how the spatial and social organisation of male and female badgers relate to the characteristics of the resources they require.

4 citations

Journal ArticleDOI
TL;DR: In this paper, two grassland communities were stratified by microrelief patterns, and random sampling designs were applied to each community as well as microsites within the community, which reduced standard errors significantly.
Abstract: The objective of this study was to determine if a stratification of microsites within range communities could be used to effectively reduce sampling variation and hence sample size. Two grassland communities were stratified by microrelief patterns. Random sampling designs were applied to each community as well as microsites within the community. Stratification of the community, based on local dniluge patterns, reduced standard errors significantly. The pooled microsite data sets were not significantly different from simple random sample data sets for the communities. Sample size reductions of 50 and 60% were observed using the microsite srmpling technique.

2 citations


Cites methods from "Two basic methodological choices in..."

  • ...A number of sampling procedures and improvements have been described in the literature during the past 5 years (Shute and West 1982, Ahmed et al. 1983, Butler and McDonald 1983, Strauss and Neal 1983, Taha et al. 1983, and Caranda and Jameson 1986)....

    [...]

References
More filters
Book
01 Dec 1969
TL;DR: In this paper, the authors introduce statistical analysis and introduce the concept of statistical analysis in statistical analysis, and propose a framework for statistical analysis for the analysis of statistical data in the literature.
Abstract: Introduction to statistical analysis , Introduction to statistical analysis , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

5,255 citations

Journal ArticleDOI
TL;DR: In this article, a system for determining range condition which considers climate, soil, and vegetation both present and potential is described, and an actual example is used to demonstrate practical application of the system to range management.
Abstract: T ODAY there are many different bases for range condition classifications. Stockmen commonly associate the term “range condition” with favorableness of the season. In this sense, good range condition may mean simply that an area recently received good rains. However, professional range conservationists have long associated good range condition with something less fleeting than good seasonal growth. In the glossary of technical terms published by the Society of American Foresters (11)) range condition is defined as “The state of health or productivity of both soil and forage of a given range, in terms of what it could or should be under normal climate and best practicable management”. This article describes a system for determining range condition which considers climate, soil, and vegetation both present and potential. It includes a review of researches that provide a scientific foundation for the system, and shows how earlier qualitative applications have been replaced by quantitative ones. An actual example is used to demonstrate practical application of the system to range management.

663 citations

Book
01 Jan 1977
Abstract: PATTERNS AND THEIR MEANING The pattern of a landscape is, in its full detail, exceedingly complex. It is generally impossible to interpret adequately the relations of species and stands to one another and the landscape by observation alone. It is consequently necessary to develop abstract representations of the pattern, representations which show some relations of communities and environments which are most significant in the landscape pattern, but show these in a form more easily comprehended and apart from the complexity of the whole. The most familiar such abstract representation is the ecological series. In the complexity of the landscape paetern, certain main-directions of vegetational and environmental change may be recognized (cf. Meusel, 1940). Recognition of major correlations of properties of vegetation with differences in environment is originally direct and intuitive, but is later influenced also by means of measurement and interpretations of the significance of factors which, like those of the soil, are not so easily observed. When a single gradient is chosen for study, stand 110 THE BOTANICAL REVIEW samples may be arranged in sequence along this gradient to form an ecological series and interpreted as a gradient of environments and communities, an ecocline. Stands may be chosen and arranged in relation to a single factor-gradient, but the ecological series shows their relation not to a factor-gradient alone, but to a complex-gradient of many correlated factor-gradients, or of characteristics of environmental complexes (Whittaker, 1956). Within the ecocline one may choose to distinguish the complex-gradient of environments and the corresponding coenocline or gradient of communities (Whittaker, 1960). Although the ecological series is an approach toward isolation of a factor and its effects, it represents the variation in certain observed properties of ecosystems as most or all of these change along the gradient chosen for study. By the ecological series, characteristics of communities may be correlated with factors of environment, but the relation need not be assumed to be one of effect and cause. Environments and communities are coupled and interacting aspects of the ecosystem; environment acts not simply on the community, but in and through the function of the ecosystem to produce observed differences in community characteristics (Whittaker, 1954b). The relation between environments and communities in an ecological series may, however, have these characteristics: (1) The environmental gradient exists and can be measured apart from the presence of the communities along it. The gradient may thus be in a sense external to or separate from the community, although the gradient as it affects organisms may be modified by the community and the function of the ecosystem. (2) The relation between the gradient and communities is consistent; similar communities are observed to occur in habitats having similar levels or intensities of the gradient. (3) The normal complexities of ecological relations, effects of other environmental factors, chance differences in communities at similar levels of the gradient, and effects of communities in modifying the gradient not correlated with the gradient, may reasonably be neglected or controlled by choice of area or stands to be studied. (4) There is reason in present ecological understanding to think that the environmental gradient has significance in relation to the functions of ecosystems, such that differences in the functions of ecosystems that develop at different levels of the gradient are expressed in observable differences in communities. When these conditions occur, the relation between the environmental gradient and the gradient of community characteristics partially approaches the ideal of the "cause CLASSIFICATION OF NATURAL COMMUNITIES 111 and effect" relation (cf. Bunge, 1961). The synecologist in this area of study is concerned in general not with cause and effect but with correlations--variables which change together through an ecological series and which are often interrelated in the functions of the ecosystems along the gradient. To some degree some of these correlations approach the special circumstances to which designation of one gradient as cause or independent variable and others as effects or dependent variables may be appropriate (cf. Major, 1951; Whittaker, 1954b). When several major gradients influencing community characteristics are recognized in a landscape, stands may be arranged into ecological series in relation to each of these. An abstract representation of the landscape pattern as a multi-dimensional coordinate system of intersecting ecological series results (Ramensky, 1930; Sukatschew, 1932; Ellenberg, i950a, 1952a; Goodall, 1954a, 1954b; Whittaker, 1956, 1960; Bray and Curtis, 1957; Curtis, 1959). This general approach to study of landscape patterns and other relations of ecosystems through ecological series and abstract patterns (or by formal statistics of correlations and factor analysis) has been termed gradient analysis (Whittaker, 1951, 1952, 1956). The term expresses the fact that this is an analytic approach to ecosystems through measurable isolates as variables, and that the basis of relating stands to one another and a principal objective of the approach is the study of interrelations of gradients of environment, species populations, and community properties. For the techniques of arranging stands in ecological series or coordinate systems, and by extension for the approach itself, the term ordination (Goodall, 1954a; from Ordnung, Ramensky, 1930) is also current. Implications of such research for problems of classification may be clarified through study of an abstract pattern based on two major complex-gradients, using these gradients as axes of a chart (Fig. 1). Properties of the pattern represented by such a chart cannot be directly identified with those of the landscape pattern. The chart is a simplification of the landscape pattern; it omits from consideration factors not fitting into the complex-gradients studied. Points in the chart may represent, not particular stands, but average or most probable stand properties at a given combination of the gradients studied. The gradients represented as continuous on the chart are frequently interrupted by edaphic and topographic discontinuity and disturbance in the field. The chart summarizes changes of stands along the full extents of gradients which may be somewhere observed in the field by walking 112 THE BOTANICAL REVIEW VEGETATION OF GREAT SlVIOKY MOUNTAINS PRTERN OF EASTERN FOREST SYSTEM

397 citations

Journal ArticleDOI
TL;DR: Comparison of ordination performance of reciprocal averaging with non-standardized and standardized principal components analysis (PCA) and polar or Bray-Curtis ordination (PO) found that RA is much superior to PCA at high beta diversities and on the whole preferable toPCA at low Beta diversities.
Abstract: SUMMARY Reciprocal averaging is a technique of indirect ordination, related both to weighted averages and to principal components analysis and other eigenvector techniques. A series of tests with simulated community gradients (coenoclines), simulated community patterns (coenoplanes), and sets of vegetation samples was used to compare ordination performance of reciprocal averaging (RA) with non-standardized and standardized principal components analysis (PCA) and polar or Bray-Curtis ordination (PO). Of these, non-standardized PCA is most vulnerable to effects of beta diversity, giving distorted ordinations of sample sets with three or more half-changes. PO and RA give good ordinations to five or more half-changes, and standardized PCA is intermediate. Sample errors affect all these techniques more at low than at high beta diversity, but PCA is most vulnerable to effects of sample errors. All three techniques could ordinate well a small (1-5 x 1-5 half-changes) simulated community pattern; and PO and RA could ordinate larger patterns (4 5 x 4-5 half-changes) well. PCA distorts larger community patterns into complex surfaces. Given a rectangular pattern (1-5 x 4-5 halfchanges), RA distorts the major axis of sample variation into an arch in the second axis of ordination. Clusters of samples tend to distort PCA ordinations in rather unpredictable ways, but they have smaller effects on RA, and none on PO. Outlier samples do not affect PO (unless used as endpoints), but can cause marked deterioration in RA and PCA ordinations. RA and PO are little subject to the involution of axis extremes that affects nonstandardized PCA. Despite the arch effect, RA is much superior to PCA at high beta diversities and on the whole preferable to PCA at low beta diversities. Second and higher axes of PCA and RA may express ecologically meaningless, curvilinear functions of lower axes. When curvilinear displacements are combined with sample error, axis interpretation is difficult. None of the techniques solves all the problems for ordination that result from the curvilinear relationships characteristic of community data. For applied ordination research consideration of sample set properties, careful use of supporting information to evaluate axes, and comparison of results of RA or PCA with PO and direct ordination are suggested.

348 citations


"Two basic methodological choices in..." refers result in this paper

  • ...Contrary to the findings of Gauch et al. (1977) r eciprocal averaging ordination (using Cornell Ecology Program 25A), did not give a better reduction of the 24 species cover data set than PCA (r 2 = ....

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