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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.

AbstractTwo Basic Methodological Choices in Wildland Vegetation Inventories: Their Consequences and Implications

Topics: Vegetation (pathology) (67%) more

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Utah State University Utah State University
DigitalCommons@USU DigitalCommons@USU
All Graduate Theses and Dissertations Graduate Studies
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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Consequences and Implications" (1979).
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Scope of study
Study area . .
Study design.
Data collection, reduction, and analysis
Using vegetation X's to predict production
Comparison of regression models including
vegetation, soil, and environmental data.
. . . . . . . . . . . . . . . . . . .

Subsets of variables in vegetation-environment
regression models .....••....•...

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Abstract: Vegetation type and its biomass are considered important components affecting biosphere-atmosphere interactions. The measurements of biomass per unit area and productivity have been set as one of the goals for International Geosphere-Biosphere Programme (IGBP). Ground assessment of biomass, however, has been found insufficient to present spatial extent of the biomass. The present study suggests approaches for using satellite remote sensing data for regional biomass mapping in Madhav National Park (MP). The stratified random sampling in the homogeneous vegetation strata mapped using satellite remote sensing has been effectively utilized to extrapolate the sample point biomass observations in the first approach.

226 citations

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  • ...Ground based sampling in functional homogeneous vegetation categories is an approach which has found acceptability in the recent past (Shute and West 1982)....


  • ...This is in concurrence with the work of Shute and West (1982)....


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Abstract: A method for mapping of forest biomass using black-and-white aerial photographs and nondestructive field sampling is described through a case study of Ladhiya subcatchment in Kumaun Himalaya, India. Forest types were mapped using aerial photographs and field checks. Each forest type was divided into five crown cover classes. Mean crown cover for each class was determined in the field. Density and basal cover were measured on reference sites. Stand biomass was estimated by using biomass estimation equations, mean girth and mean density on the reference sites. Regression equations were developed between crown cover and basal cover, and between crown cover and stand biomass. Mean basal cover and mean stand biomass for each photo-interpreted crown cover class were estimated through these equations. Forest biomass values were substituted for crown cover classes on the interpreted map.

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Abstract: Forest is a major resource and plays a vital role in maintaining the ecological balance and environmental setup. Over utilization of forest resource has resulted in its depletion. The changes in tropical forest cover are matter of global concern due to its ability of promoting role in carbon cycle. This renewable resource continues to decrease at accelerated rate. Accurate and timely information in regular interval on the distribution of natural resources on earth is of top priority for understanding dynamics of the human induced land cover/land use accelerated changes. This information can be further utilized in understanding biophysical processes of the earth. In India and the other developing countries it is mostly been lost for the agricultural practices. Aerospace technology is a potential means of collecting information about natural resources including forests at any desired time. The technology is considered important to revise or update available information. The present paper addresses the status of tropical forest and requirements for its monitoring and assessment. It discusses the potential of the remote sensing technology for managing the forests, in general and sustaining the pace of development in this technology. It focuses the technology trends and techniques for tropical forest assessment at different scale and levels.

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TL;DR: Process based models were developed to make use of the remotely sensed data available on monthly basis for estimation of Net Primary Productivity (NPP).
Abstract: Traditionally biomass estimation involved harvesting of the trees. As the forest cover decreased, there became the need for non-destructive methods for volume/biomass estimation. Methods were developed to relate the biomass with girth, height etc. Component-wise biomass equations were developed, which were used to estimate biomass at the plot level. In last couple of years satellite remote sensing has been successfully used for biomass and productivity estimation. The unique characteristic of plants is displayed by its reflectance in red and infrared region of electro-magnetic radiation. These have relationship with the biophysical parameters of plants. Therefore, process based models were developed to make use of the remotely sensed data available on monthly basis for estimation of Net Primary Productivity (NPP). Production efficiency model was used to estimate the NPP at the patch level, which takes Intercepted Photosynthetically Active Radiation (IPAR) and photosynthetic efficiency as input parameters to estimate NPP.

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Abstract: Introduction to statistical analysis , Introduction to statistical analysis , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

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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.

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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

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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.

340 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 = ....