• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3
  • 1
  • 1
  • Tagged with
  • 7
  • 7
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Using Repeat Color Photography as a Tool to Monitor Rangelands

Howery, Larry D., Sundt, Peter C. 12 1900 (has links)
6 pp. / Originally published: 1998 / This article provides an introduction to repeat color photography and explains how it can be used as an important part of a comprehensive rangeland monitoring program. Reviewed 12/2014. Originally published 05/1998.
2

Cooperative Extension Rangeland Monitoring Program

Ruyle, George B., Young, Deborah January 2004 (has links)
4 pp.
3

Rangeland Monitoring and the Parker 3-Step Method: Overview, Perspectives and Current Applications

Ruyle, George B., Dyess, Judith 08 1900 (has links)
9 pp. / Principles of obtaining and interpreting utilization data on rangelands / Rangeland monitoring is essential for making sound management decisions. Monitoring requires repeated measurements of the same attributes over time. Perhaps the earliest and most widespread rangeland management monitoring data collection protocol was the development and establishment of the Parker 3-step Method on U. S. Forest Service rangelands, beginning in 1948. This method collected both objective and subjective data and provided a scoring technique for assessment purposes. This paper describes the development of the Method and suggests ways to summarize the ecological attributes collected on Parker transects, analyze the data and reinterpret them based on trends in plant species abundance, composition and soil cover.
4

Assessing long-term change in rangeland ecological health using the Western Australian rangeland monitoring system

Russell, Peter John January 2007 (has links)
The rangelands or semi-arid and arid regions of Western Australia occupy about 87 percent of the land area. Pastoral grazing of managed livestock, mainly sheep and cattle, occurs over much of this area, with an increasing proportion being allocated to the state conservation estate. Rangeland monitoring began at the local scale in the 1950s and since then has been closely tied to the needs of the pastoral industry. By 1992 a regional-scale, ground-based system was in place after two decades of trialling precursor techniques. The state-wide pastoral monitoring programme, known as the Western Australian Rangeland Monitoring System (WARMS), helps to monitor the state’s natural vegetation and soil resources. Change in soil and vegetation attributes through time, in response to climatic conditions, herbivore grazing, fire and other natural and anthropogenic drivers in the rangelands is known as change in range condition or range trend. When range condition is used in an ecological context, as it is in this research, an improving trend implies an improvement in ecological integrity or ecosystem health. In contrast, a declining trend implies a reduction in integrity, otherwise known as natural resource degradation. The principal objective of this study is to produce a regional-scale, long-term quantitative assessment of range condition change in the southern rangelands of Western Australia, using WARMS transect data. Previous analyses of the WARMS database have examined selected vegetation parameters, but this study is the first to calculate a single integrated range condition index. The assessment covers an area of approximately 760,000 km2, stretching southeast from the southern Pilbara region through the Gascoyne-Murchison and Goldfields regions to the Nullarbor region on the Great Australia Bight. / WARMS is designed to provide data and information for assessing regional and long-term changes in rangeland ecological condition. It consists of two principal parts: (1) numerous permanent field monitoring sites and (2) a large relational database. By the end of 2006, there were 980 WARMS sites located on 377 pastoral leases (stations) in the southern rangelands of Western Australia. Average lease size is 202,190 ha and the largest is 714,670 ha. The total area occupied by leases (pastoral plus leases converted to the conservation estate) is approximately 76,250,000 ha. WARMS sites are at an average density of 2.6 sites per lease or 1 site per 77,780 ha of pastoral rangeland. Field-recorded metrics include 11 soil surface parameters and four plant parameters (location on belt-transect, species, height and maximum canopy extent). The field data collection protocol has remained essentially unchanged since 1992 and new field data are captured at each site on a 5-year cycle. This is the most extensive quantitative, ground-based rangeland monitoring system in Australia. This assessment of range condition is based a suite of soil and vegetation indices derived from the WARMS transect field metrics. Seven basic indices have been derived and algorithmically combined into three higher-order indices, one for each of three components of ecological integrity: composition, function and structure. The three indices are then combined into an overall index of ecological health called the Shrubland Range Condition (SRC) Index. In addition, the indices have been assigned to particular time-slices based on the field acquisition date of their component metrics, allowing the calculation of change through time. / The combination of the hierarchical index framework, the use of time-slices and GIS mapping techniques provided a suitable analysis platform for the elucidation of spatial and temporal change in rangeland ecological integrity or health at WARMS sites. The nature of change in the SRC Index and the landscape function, vegetation structure and vegetation composition sub-indices has enabled possible causes to be inferred. The patterns of range condition and change are complex at all landscape scales. However, based on analysis of the WARMS sites, range condition is considerably more variable, in space and time, in the northern parts of the southern rangelands compared to the southern parts, with the exception of the Nullarbor region. Through time, the Ashburton and Gascoyne regions consistently demonstrate the largest area (site clusters) of change and the greatest magnitude of change. For many areas, range trend has fluctuated markedly between improvement and decline since the mid-1990s. However, there are two large clusters of sites which show continuing decline through more than two decades. The legacy of historical degradation and ongoing poor land stewardship (principally through over-stocking) is hindering the widespread recovery in range condition, despite more than a decade of good rainfall seasons. An uncommon exception to this sad story is a group of sites located in the upper region of the Gascoyne catchment, where there has been almost continuous improvement over the same period. This work also provides empirical evidence of a fundamental difference in the behaviour of surface water-flows in different catchment types. / Using the Landscape Function Factor (LFF), there is conspicuous regional differentiation of sites located in exorheic catchments from those located in endorheic-arheic catchments. In general, sites located in the coastal draining exorheic catchments exhibit greater rates of soil erosion compared to sites located in the other internally draining catchment types; the different erosional regimes are probably related to the nature of the ultimate and local base-levels associated with each catchment type. This has important implications for the long-term management of the rangelands of Western Australia.
5

Rangeland Monitoring Using Remote Sensing: An Assessment of Vegetation Cover Comparing Field-Based Sampling and Image Analysis Techniques

Boswell, Ammon K. 01 March 2015 (has links) (PDF)
Rangeland monitoring is used by land managers for assessing multiple-use management practices on western rangelands. Managers benefit from improved monitoring methods that provide rapid, accurate, cost-effective, and robust measures of rangeland health and ecological trend. In this study, we used a supervised classification image analysis approach to estimate plant cover and bare ground by functional group that can be used to monitor and assess rangeland structure. High-resolution color infrared imagery taken of 40 research plots was acquired with a UltraCam X (UCX) digital camera during summer 2011. Ground estimates of cover were simultaneously collected by the Utah Division of Wildlife Resources' Range Trend Project field crew within these same areas. Image analysis was conducted using supervised classification to determine percent cover from Red, Green, Blue and infrared images. Classification accuracy and mean difference between cover estimates from remote sensed imagery and those obtained from the ground were compared using an accuracy assessment with Kappa statistic and a t-test analysis, respectively. Percent cover estimates from remote sensing ranged from underestimating the surface class (rock, pavement, and bare ground) by 27% to overestimating shrubs by less than 1% when compared to field-based measurements. Overall accuracy of the supervised classification was 91% with a kappa statistic of 0.88. The highest accuracy was observed when classifying surface values (bare ground, rock) which had a user's and producer's accuracy of 92% and 93%, respectively. Although surface cover varied significantly from field-based estimates, plant cover varied only slightly, giving managers an option to assess plant cover effectively and efficiently on greater temporal and spatial extents.
6

Terrestrial survey and remotely-sensed methods for detecting the biological soil crust components of rangeland condition

Ghorbani, Ardavan January 2007 (has links)
This thesis considers various aspects of the use of ground-based methods and remote sensing of Biological Soil Crusts (BSC). They are mostly distributed in winter rainfall dominated areas such as those at Middleback Field Centre (MFC) in South Australia. They can be used potentially as an indicator of rangeland condition by estimating grazing pressure (trampling). Two BSC based indicators for rangeland condition assessment are species composition and cover. While there is strong agreement that BSC composition is a good indicator, there is less agreement that BSC cover alone is a good indicator. Although BSC have been included in previous remotely-sensed studies, their spectral characteristics, and hence their contributions to remotely-sensed spectral signatures, are not well known. Data collection methods were refined for suitable method selection, stratification and site characterization, and morphological/ functional group classification. Cover data of BSC were collected using a 100 m line-intercept method on the stratified land units and statistical analyses were based on the cover variance analyses. Spectra of BSC groups were collected and characterized for different remote sensing indices. Five grazing gradient models based on collected spectra were developed for the evaluation of BSC effect on remotely-sensed data. Both existing and newly developed remote sensing indices were examined for BSC detection. Sampling for cover of BSC in the field showed that there is indeed a detectable change with distance from water, suggesting that BSC cover can be used as an indicator of rangeland condition, provided that appropriate stratification of the study sites is carried out prior to sampling, and spectral differences in morphological and functional groups are taken into account. Spectral analysis of BSC components showed that different classes of organisms in the crusts have different spectral characteristics, and in particular, that the (commonly-used) perpendicular vegetation index (PD54) is not suitable for detecting BSC. On the other hand, ground-level spectral modelling showed that the Normalized Difference Vegetation Index (NDVI) and Soil Stability Index (SSI) did show a distinguishable contribution from BSC. A procedure for detecting cover of BSC was developed for image taken during the period after an effective rain, in contrast to the normal practice of selecting images of dry surfaces for interpretation. The most suitable intervals appears to be 2-4 days after rain in late autumn, winter and early spring. Of the existing indices, the SSI is the best for estimating cover of BSC from Landsat images. However, eight new indices, specifically designed for detection of BSC were developed during the cource of this work. The best results were obtained for indices using using the middle-infrared bands. These results are promising for application to rangeland monitoring and suggest that BSC cover is an important indicator of rangeland condition if appropriate stratification, classification and data-collection methods are used. The effects of BSC cover on a remotely-sensed method are considerable, and thus they can not be neglected during image interpretation. There are different phenological patterns for BSC, annual and perennial elements, thus there is the possibility for the selection of imagery based on each phenological stage to detect these elements. Application of certain indices such as the PD54 may create mis-estimation of land covers. Although some of the existing and newly developed indices had significant results for BSC cover estimation, there is a requirement for a standalone remotely-sensed method to conclude the best index.
7

Influence of Soil Water Repellency on Post-fire Revegetation Success and Management Techniques to Improve Establishment of Desired Species

Madsen, Matthew D. 17 December 2009 (has links) (PDF)
The influence of soil water repellency (WR) on vegetation recovery after a fire is poorly understood. This dissertation presents strategies to broaden opportunities for enhanced post-fire rangeland restoration and monitoring of burned piñon and juniper (P-J) woodlands by: 1) mapping the extent and severity of critical and subcritical WR, 2) determining the influence of WR on soil ecohydrologic properties and revegetation success, and 3) evaluating the suitability of a wetting agent composed of alkylpolyglycoside-ethylene oxide/propylene oxide block copolymers as a post-fire restoration tool for ameliorating the effects of soil WR and increasing seedling establishment. Results indicate that: • Post-fire patterns of soil WR were highly correlated to pre-fire P-J woodland canopy structure. Critical soil WR levels occurred under burned tree canopies while sub-critical WR extended out to approximately two times the canopy radius. At sites where critical soil WR was present, infiltration rate, soil moisture, and vegetation cover were significantly less than at non-hydrophobic sites. These parameters were also reduced in soils with subcritical WR relative to non-hydrophobic soils (albeit to a lesser extent). Aerial photography coupled with feature extraction software and geographic information systems (GIS) proved to be an effective tool for mapping P-J cover and density, and for scaling-up field surveys of soil WR to the fire boundary scale. • Soil WR impairs seed germination and seedling establishment by decreasing soil moisture availability by reducing infiltration, decreasing soil moisture storage capacity, and disconnecting soil surface layers from underlying moisture reserves. Consequently, soil WR appears to be acting as a temporal ecological threshold by impairing establishment of desired species within the first few years after a fire. • Wetting agents can significantly improve ecohydrologic properties required for plant growth by overcoming soil WR; thus, increasing the amount and duration of available water for seed germination and seedling establishment. Success of this technology appears to be the result of the wetting agent increasing soil moisture amount and availability by 1) improving soil infiltration and water holding capacity; and 2) allowing seedling roots to connect to underling soil moisture reserves.

Page generated in 0.1445 seconds