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.

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.

Low-tech rock structures called gabions are commonly used in dryland stream channels to reduce erosion, slow floodwaters, and increase infiltration. Gabions may also increase water availability for riparian vegetation, and increase the duration of surface flow in ephemeral stream channels. However, their effects on infiltration and recharge are not well-understood. This study tested low-cost methods for easily quantifying the total infiltration induced by gabion construction in an ephemeral stream channel, over the course of a single flow event. We used well-established methods to find point infiltration fluxes from subsurface temperature time-series. Unique to this study, we then upscaled these measurements to the gabion’s entire area of influence using time-lapse photo data, which recorded the onset of flow and the duration of ponding. For a flow lasting ~5 hours, we ran 225 model scenarios, estimating that a single gabion could have increased the total infiltrated volume in the channel reach between it and the next gabion by as much as 255% or as little as 0%, but the most likely scenario is a 10.8% increase. We found the photo data to be invaluable in obtaining these estimates, and in understanding the dynamics of a remote field site. Future work would benefit from more precise measurements of point infiltration fluxes and better records of ponded surface area over time. If these improvements are made and our estimates can be replicated reliably, they would suggest that gabions are a more powerful restoration and management tool than previously understood.

6 pp. / Originally published 09/2000. / The objectives of this article are to provide an overview of the major grazing systems that have been used on rangelands in the western U. S. and Canada, to summarize the conditions under which they may be applicable, and to highlight examples from the southwestern U. S. when relevant. Revised 12/2014. Originally published 09/2000.

Concerns were raised over the past decades, on the degradation condition of arid and semi-arid rangelands in South Africa, mainly in areas under communal land management. Baseline information on soil quality is essential to monitor changes in land conditions and assess impacts of land uses and management over time. The objectives of this study, initiated within the framework of the Desert Margins Program, were to characterize and establish baseline indicators of soil quality health, and to investigate the potential effects of grazing and exclusion management (hypothesized as grazing effect) on selected soil properties in the western Bophirima District in South Africa. Soils were characterized for physical, chemical, enzymatic activity and microbial biomass properties, and grazing effects were evaluated on selected properties. The aboveground herbaceous species composition and biomass production were also determined. Sandy, poor fertile soils (low organic carbon and phosphorus) characterized all sites. Various levels of enzymatic and microbial biomass were recorded at the sites. Grazing had no significant effects on most of soil chemical properties, but did affect selected enzymatic activities, site-specifically. No significant differences of grazing effects were observed on soil microbial biomass. The inconsistent responses of soil properties across the sites prompt to caution regarding the generalization and/or extrapolation of grazing effects to other areas, without consideration of the prevailing environmental and management characteristics to each site. Notwithstanding the alarming plea about degradation at these communal sites, indicators of soil quality did not significantly differ between communal and surrounding commercial and/or game managed areas, despite their apparent vegetation degradation. The results showed that rangeland under the communal management were characterized by increaser species of low grazing value, but this situation did not necessarily interpret severe soil degradation as tacitly described. Soil degradation depends on land use, management and environmental conditions, and references are needed to assess degradation. Important interrelationships between the aboveground vegetation and soil belowground activity were observed. This emphasized the need to integrate both soil and vegetation into rangeland monitoring, as these interrelationships and associated ecological processes sustain rangeland health. Further research is needed to re-examine the "inferred degradation of rangelands in communal areas, taking into consideration their history, and using appropriate baselines and references sites. Only then, can degradation trends and hotspots be identified and thereof, appropriate management decisions (through participatory research) taken locally to combat degradation and sustain long-term rangeland resources uses. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2007.

Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2007.

Concerns were raised over the past decades, on the degradation condition of arid and semi-arid rangelands in South Africa, mainly in areas under communal land management. Baseline information on soil quality is essential to monitor changes in land conditions and assess impacts of land uses and management over time. The objectives of this study, initiated within the framework of the Desert Margins Program, were to characterize and establish baseline indicators of soil quality health, and to investigate the potential effects of grazing and exclusion management (hypothesized as grazing effect) on selected soil properties in the western Bophirima District in South Africa. Soils were characterized for physical, chemical, enzymatic activity and microbial biomass properties, and grazing effects were evaluated on selected properties. The aboveground herbaceous species composition and biomass production were also determined. Sandy, poor fertile soils (low organic carbon and phosphorus) characterized all sites. Various levels of enzymatic and microbial biomass were recorded at the sites. Grazing had no significant effects on most of soil chemical properties, but did affect selected enzymatic activities, site-specifically. No significant differences of grazing effects were observed on soil microbial biomass. The inconsistent responses of soil properties across the sites prompt to caution regarding the generalization and/or extrapolation of grazing effects to other areas, without consideration of the prevailing environmental and management characteristics to each site. Notwithstanding the alarming plea about degradation at these communal sites, indicators of soil quality did not significantly differ between communal and surrounding commercial and/or game managed areas, despite their apparent vegetation degradation. The results showed that rangeland under the communal management were characterized by increaser species of low grazing value, but this situation did not necessarily interpret severe soil degradation as tacitly described. Soil degradation depends on land use, management and environmental conditions, and references are needed to assess degradation. Important interrelationships between the aboveground vegetation and soil belowground activity were observed. This emphasized the need to integrate both soil and vegetation into rangeland monitoring, as these interrelationships and associated ecological processes sustain rangeland health. Further research is needed to re-examine the "inferred degradation of rangelands in communal areas, taking into consideration their history, and using appropriate baselines and references sites. Only then, can degradation trends and hotspots be identified and thereof, appropriate management decisions (through participatory research) taken locally to combat degradation and sustain long-term rangeland resources uses. / Thesis (Ph.D. (Environmental Science))--North-West University, Potchefstroom Campus, 2007.

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.

Decades of overgrazing have left many rangelands in northwestern Mexico in poor condition. This has led to the practice of converting native rangeland plant communities to buffelgrass pastures. Buffelgrass (Pennisetum ciliare) is a perennial bunchgrass native to Africa. Both the extent of buffelgrass pastures within Mexico and the impacts of land conversion on biodiversity and ecosystem functioning. In the present study I address the effects of land conversion on the productivity and diversity of rangelands in the southern Sonoran Desert in the state of Sonora, Mexico. First, using satellite imagery from the Landsat mission, I found that rates of land conversion in the most heavily affected region of Sonora have continued to accelerate over the past three decades and that productivity of buffelgrass pastures is lower than that of native rangeland. Next, I examined the impacts of land conversion on the diversity and structure of plant communities and ant assemblages across a rainfall driven gradient of productivity in central Sonora. The regional extent of this land use change allowed me to explore the interaction between site productivity and land conversion. Within native rangeland I detected strong positive relationships between productivity and the species richness of perennial plant communities, but only weak positive relationships between productivity and species richness of ant assemblages. These results were discussed in the context of species diversity theory. Land conversion reduced the species richness of perennial plant communities by approximately 50% at both local and regional scales, whereas the species richness of ant assemblages was reduced by 17% at the local scale and only 8% at the regional scale. I found no evidence for an interaction between site productivity and land conversion in either plant communities or ant assemblages. The implications of these findings for long-term trajectories of biodiversity in the southern Sonoran Desert are discussed.

Part of the problem with implementing a rangeland insurance program is that the acreage of different pasture types, which is required in order to determine an indemnity payment, is difficult to measure on the ground over large areas. Remote sensing techniques provide a potential solution to this problem. This study applied single-date SPOT (Satellite Pour IObservation de la Terre) imagery, field collected data, and geographic information system (GIS) data to study the classification of land cover and vegetation at species level. Two topographic correction models, Minnaert model and C-correction, and two classifying algorithms, maximum likelihood classifier (MLC) and artificial neural network (ANN), were evaluated. The feasibility of discriminating invasive crested wheatgrass from natives was investigated, and an exponential normalized difference vegetation index (ExpNDMI) was developed to increase the separability between crested wheatgrass and natives. Spectral separability index (SSI) was used to select proper bands and vegetation indices for classification. The results show that topographic corrections can be effective to reduce intra-class rediometric variation caused by topographic effect in the study area and improve the classification. An overall accuracy of 90.5% was obtained by MLC using Minnaert model corrected reflectance, and MLC obtained higher classification accuracy (~5%) than back-propagation based ANN. Topographic correction can reduce intra-class variation and improve classification accuracy at about 4% comparing to the original reflectance. The crested wheatgrass was over-estimated in this study, and the result indicated that single-date SPOT 5 image could not classify crested wheatgrass with satisfactory accuracy. However, the proposed ExpNDMI can reduce intra-class variation and enlarge inter-class variation, further, improve the ability to discriminate invasive crested wheatgrass from natives at 4% of overall accuracy. This study revealed that single-date SPOT image may perform an effective classification on land cover, and will provide a useful tool to update the land cover information in order to implement a rangeland insurance program.