Aug 17, 2001 - Paul Gould1, Brendan Lay1, Rodger Tynan2 and Ian Watson3 ...... Gawler Ranges (Tynan 1995) Soil Conservation Districts that summarised ...
Rangeland monitoring, resource inventory, condition assessment and lease inspection activities in South Australia conducted by Primary Industries and Resources SA Paul Gould1, Brendan Lay1, Rodger Tynan2 and Ian Watson3 1 2 3
- Primary Industries and Resources SA - South Australian Department of Environment and Heritage (now retired) - Department of Agriculture, Western Australia
Report prepared for the Rangeland Theme of the National Land and Water Resources Audit
July 2001 Version 1.0
SUMMARY POINTS • •
•
• • • • •
Primary Industries and Resources SA (PIRSA) has a comprehensive, integrated program of resource inventory, resource condition and lease assessment, lease inspection and rangeland monitoring in place. Each of the 222 pastoral properties on 328 leases covering 409,000 km2 of the rangelands in South Australia now have resource and lease inventory information, resource condition assessments, baseline monitoring sites established and priority paddocks identified for management action. About 5,500 photopoint monitoring sites have been established, approximately 15,000 Land Condition Index sample points have been assessed and about 4,500 individual paddocks (or unfenced grazing areas in cattle country) have been assessed and assigned a priority for land management action and further inspection. This work is primarily driven by requirements under the Pastoral Land Management and Conservation Act [1989]. The focus for the PIRSA activities is on reporting at lease scale (under the Act) rather than at district or state scale for miscellaneous purposes. Lease scale reports remain confidential to the Pastoral Board and the lessee. Little aggregated information is publicly available. There is no firm schedule for reassessment of leases or systematic reassessment of photopoint monitoring sites. However, all leases will be reassessed and photopoints revisited within 14 years of the initial work. The Pastoral Land Management and Conservation Act aims to prevent degradation, therefore re-inspection and reassessment activities are targetted at those areas most at risk. The theoretical basis for the Pastoral Land Management and Conservation Act focuses on conservation of indigenous resources, rather than on those resources for pastoral purposes per se.
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CONTENTS Summary points............................................................................................................................ 2 Contents........................................................................................................................................ 3 Introduction .................................................................................................................................. 5 Purpose of the Pastoral Program .................................................................................................. 7 Primary drivers ......................................................................................................................... 7 The Pastoral Land Management and Conservation Act [1989] ........................................... 7 Secondary drivers ..................................................................................................................... 7 National Principles and Guidelines for Rangeland Management ........................................ 8 Commonwealth State of Environment Report ..................................................................... 9 National Strategy for Conservation of Australia’s Biological Diversity ............................. 9 Managing Natural Resources in Rural Australia for a Sustainable Future ........................ 10 The Pastoral Program ................................................................................................................. 11 An integrated lease assessment, monitoring and inspectorial approach ................................ 11 Arid lands administration ....................................................................................................... 12 Resource inventory................................................................................................................. 14 Lease Assessment Program summary .................................................................................... 15 Lease Assessment Reports ................................................................................................. 15 Land Condition Index (used on the majority of southern leases) .................................. 16 Summary of the LCI................................................................................................... 16 Three land condition classes ...................................................................................... 20 Basic assumptions of the LCI..................................................................................... 20 Preparation of the LCI guidelines for each Soil Conservation District...................... 20 Remote sensing (Grazing Gradient) on northern leases................................................. 21 Lease Assessment Overview Reports ................................................................................ 24 Contents of Lease Assessment Overview Reports ......................................................... 24 Background and context................................................................................................. 25 Land condition................................................................................................................ 25 Photopoints..................................................................................................................... 26 Lease inspections and priority paddocks........................................................................ 26 District level land management issues ........................................................................... 26 Pastoral Program photopoint monitoring sites ....................................................................... 27 Summary ............................................................................................................................ 27 Site stratification ................................................................................................................ 29 Attributes assessed at photopoints...................................................................................... 29 Site details ...................................................................................................................... 29 Jessup transect ............................................................................................................ 30 Crown Separation Ratio ............................................................................................. 30 Site Condition Estimate.............................................................................................. 31 Erosion type and severity ........................................................................................... 32 Site layout....................................................................................................................... 33 Site photograph .............................................................................................................. 33 History of the photopoint monitoring system .................................................................... 34 Lease inspection program....................................................................................................... 34 Biodiversity and nature conservation ..................................................................................... 35 Databases................................................................................................................................ 36 Land use and tenure in South Australia - past and current......................................................... 37 List of acronyms......................................................................................................................... 40 Contact details 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References .................................................................................................................................. 42
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INTRODUCTION In South Australia’s rangelands, a pastoral lease is the only form of tenure that can be granted over Crown land that is to be used for long-term grazing purposes. Under the Pastoral Land Management and Conservation Act [1989] a pastoral lease cannot be granted or extended without an assessment of the condition of the land (Lange et al. 1994). Because of this legislation, South Australia has the most comprehensive and integrated program of resource inventory, resource condition assessment, range monitoring and lease inspection of any of the Australian states and the Northern Territory. The Administrative structure of the South Australian Pastoral Board and Primary Industries and Resources SA (PIRSA) ensure that there are direct links between the Board, charged with administering the Act, PIRSA staff who directly support the Board and PIRSA staff who are engaged in the field work and report preparation on behalf of the Board. Between 1990 and 2000, resource inventory mapping was completed for the 409,000 km2 of land under pastoral tenure in South Australia. Each of the 222 pastoral properties (on 328 leases) had resource condition assessments prepared. Areas of land degradation were documented at the sub-paddock scale, following the assessment of about 4,500 paddocks (or unfenced grazing areas in cattle country). About 5,500 photopoint monitoring sites were established and about 15,000 Land Condition Index points were sampled.
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Table 1. Summary of resource inventory, resource condition and range monitoring activities. Scale
Sub-paddock to paddock
Lease
Attribute Resource mapping
Resource condition
District to State (by area or range type) Land Systems originally mapped at Soil Conservation District (SCD) or 1:250,000 map sheet scale.
A paddock based assessment, that is largely subjective - done at the time of lease assessment.
Aggregated summary of Land Condition Index (LCI) for each lease (about 80 - 100 points per lease) on those areas of southern leases where it was done. Not possible where LCI not used, except in those areas where the Grazing Gradient technique was trialed.
Lease Assessment Overview Reports (e.g. Tynan 1995). In the Gawler Ranges SCD, 3,611 LCI samples were captured. Resource condition at the District scale is not available from operational means (can be done over the 2 Landsat scenes of the MO SCD.)
Range monitoring
Single photopoints within each paddock, supplemented by obervational records to determine how general the trends are.
Aggregated summary of change at all photopoints on a lease (approx 20).
Aggregated summary of change at all (or a large sample of) photopoints for that district/range type etc. No schedule in place to do this. At a maximum, 14 years will elapse between photopoint reassessments.
Areas of concern
“Priority Paddocks” nominated within Lease Assessment Reports.
Lease level recommendations arising from Lease Assessment Reports.
Lease Assessment Overview Reports (e.g. Tynan 1995).
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PURPOSE OF THE PASTORAL PROGRAM Under the Australian Constitution, State and Territory Governments have primary responsibility for the management of natural resources within their respective jurisdictions. The Commonwealth has responsibility for the management of land it owns and for coordinating responses for “national” issues. It exercises this latter responsibility through the coordination and expression of national land use policy, for example the development of National Principles and Guidelines for Rangeland Management, and the National Strategy for the Conservation of Australia’s Biological Diversity. There are a number of drivers for these activities. These include primary and secondary drivers. Primary drivers exert direct control over relevant departmental resources and activities. Secondary drivers do not exert direct control but nevertheless, influence the need to monitor, assess and report on South Australia’s rangelands.
Primary drivers The Pastoral Land Management and Conservation Act [1989] The primary driver of the SA activities is the Pastoral Land Management and Conservation Act [PLMCA 1989]. [http://www.parliament.sa.gov.au:8080/ISYSquery/IRLC6E7.tmp/8/doc] or [http://www.parliament.sa.gov.au:8080/acts-list.htm] The Act explicitly requires all pastoral lands in South Australia to be assessed (between 1990 and 2000), for a baseline monitoring system to be installed and for areas of concern to be identified. It also provides for continuing tenure to be conditional upon the land being maintained or improved. The objectives under the PLMCA specify sustainable pastoral production without degrading the land (which includes indigenous flora and fauna) The Act and the Administrative and Policy Guidelines developed by the Pastoral Board contain specific detail about what is required to monitor and assess the rangelands. The Act is also specific about the administrative use of the monitoring and assessment data. Security of tenure is conditional upon the condition of the resource and change in condition over time.
Secondary drivers There are also a number of secondary drivers, for which the Pastoral Program satisfies some objectives, but which do not exert direct authority, nor contribute specifically to its funding. These include, but are not limited to the following: • The National Principles and Guidelines for Rangeland Management; • Commonwealth State of Environment Reporting; • The National Strategy for the Conservation of Australia’s Biological Diversity; • Natural Resource Management Discussion paper - Managing Natural Resources in Australia for a Sustainable Future; • The National Land and Water Resources Audit [http://www.nlwra.gov.au/]; SA_Range monitoring & assessment activities (Ver1).pdf Page 7
• • • • • • • •
The National Drought Alert Program; The National Strategy on Ecologically Sustainable Development; Inter Governmental Agreement on the Environment; Other National Agreements Strategies and Programs; The International Convention on Desertification; TheUN Convention on Biological Diversity; Agenda 21, and; Other International trade and resource agreements and conventions;
National Principles and Guidelines for Rangeland Management The National Principles and Guidelines for Rangeland Management (NPGRM), a joint initiative between the states and Commonwealth, was very clear on the need to monitor condition and trends in Australia’s rangelands (ANZECC and ARMCANZ 1999). [http://www.affa.gov.au/armcanz] “Ongoing research and development are constantly improving the knowledge base on which decisions are made. In addition, decision making also needs the support of an adequate monitoring program, capable of detecting the condition and trend of rangeland resources, at a regional, land type and property level. The information from monitoring is essential for managers to enable them to manage for desired outcomes and provides a basis for corrective action.” (ANZECC and ARMCANZ 1999; p28) GUIDELINE 16 Rangeland condition and trends should be assessed through an expanded monitoring and evaluation program that incorporates indicators of production, biodiversity, water resource condition, climate and socio-economic factors on a regional and biophysical basis.
Recommended Actions 16.1 Governments, in consultation with rangeland users and managers, should develop agreed criteria and indicators for ecologically sustainable rangeland management and business viability. 16.2 Develop comprehensive, cost-effective monitoring programs to underpin implementation of criteria and indicators for ecologically sustainable rangeland management at a range of scales. 16.3 The opportunity created by the National Land and Water Audit must be used to establish a national rangeland monitoring program to determine trends in the long term health of Australia’s rangelands at a regional, land type and property level. 16.4 Governments should establish and use effective monitoring mechanisms of socioeconomic changes within the rangelands, including access to services and gaps and deficiencies in delivery mechanisms. 16.5 Monitoring data should be used by all decision makers in their policy development and planning processes and, in particular, by Government agencies in developing State of the Environment and other Reports. SA_Range monitoring & assessment activities (Ver1).pdf Page 8
Commonwealth State of Environment Report The Commonwealth Government now has a regular program of State of the Environment (SoE) reporting (Commonwealth of Australia 1996). There is an ongoing expectation that the condition and trends of Australia’s land resources will be regularly reported within this program. Table 6.2 of the 1996 SoE report used modified data from the Kingoonya Soil Conservation Board Overview Report (Anon 1991) to help report on land condition across Australia’s rangelands.
National Strategy for Conservation of Australia’s Biological Diversity The National Strategy for Conservation of Australia’s Biological Diversity (NSCABD), (Anon 1996) explictly recognises that long term monitoring is an important process for improving understanding of biological diversity and the factors that threaten it. The NSCABD calls for: “… (A) national coordinated program of long-term ecological monitoring to document patterns of change or lack of change in order to establish a baseline for understanding the impact of such change or lack of it on natural communities, ecosystems and ecological processes, and to detect changes in biological diversity and their causes. The program will: (a) combine remote sensing with a national network of secure field-based monitoring sites in representative habitats; (b) develop and encourage the application of national monitoring protocols involving standardised sampling designs and techniques for testing management regimes and strategies, including rehabilitation and reintroductions; (c) use biological diversity indicator groups to reveal the impacts of environmental disturbance; (d) establish properly constituted and supported assessment panels or monitoring committees, or both, comprising representatives of industry, non-government conservation organisations, other appropriate community groups and governments; (e) accelerate research into new, cost-effective methods of monitoring; (f) integrate with an ecological research program aimed at improving our understanding of long-term and event-driven ecological processes.” The NSCABD also recognises the need to research and monitor the impact of total grazing pressure in rangelands on biological diversity and the resilience and regenerative capacity of palatable species.
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Managing Natural Resources in Rural Australia for a Sustainable Future This discussion paper (Anon 1999) was released by the Federal Minister for Agriculture, Fisheries and Forestry in early 2000. The need to monitor natural resources is clearly outlined in several sections.
Natural resource management goals and objectives are to have clear and measurable outcomes, requiring comprehensive monitoring and assessment to evaluate progress and identify areas for refinement (Principles p 10) The strategic approach to extending knowledge and information involves improving access to data and information and increased monitoring (p. 17) Mechanisms for improving data and information—and for monitoring the effectiveness of actions—are an essential part of planning and implementing regional strategies (Regional strategies, p. 36). Development of sustainability indicators (p. 80) … sustainability indicators should be capable of monitoring change in the condition of the natural resource base … The following features characterise a best-practice regional plan for natural resource management: - a regional profile of natural resources’ condition and economic and social characteristics - …indicators … to monitor progress towards sustainability and evaluate the impacts of particular management practices. - sustainability indicators that are useable at the regional scale … robust and affordable systems for sharing data (are required) at the national, State and Territory, regional and farm levels. In meeting the data and information requirements, there is a need to (p. 82): - develop a system for data management, analysis and distribution, including guidelines and protocols to ensure national compatibility and comparability;
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THE PASTORAL PROGRAM An integrated lease assessment, monitoring and inspectorial approach In South Australia, PIRSA have a comprehensive, integrated program of land administration, lease assessment, resource assessment, lease inspection and scientific monitoring with good links to biodiversity and nature conservation work. The bulk of the work program to meet this agreement began in 1990 and was completed in late 2000. Teams of two field staff worked on specific leases, generally spending two weeks on each lease assessing the land condition, compiling data on infrastructure and setting up a baseline monitoring system. A major role of the program (40% of time) was the building a Geographic Information System (GIS) coverage of all pastoral leases. This included the location of watering points, fencelines and tracks (Tynan 2000). The assessment methods to determine the land condition and the capacity of the land to carry stock vary between the southern (mostly sheep) and northern (cattle) leases. On the southern leases, which largely consist of relatively homogenous chenopod shrublands, small paddocks and reliable winter rainfall, the Land Condition Index (LCI) (Lange et al. 1994) was used. On the northern leases, where rainfall is more erratic, paddocks are much larger and the vegetation is more ephemeral, the non-equilibrium dynamics are not suited to the LCI technique and subjective paddock based assessments were used. The Grazing Gradient remote sensing technique was also trialled in the northern areas but is not operational on a broad scale. While the Pastoral Program of PIRSA comprises an integrated package, and there is considerable overlap between the various activities, it can be split into the following categories for the purpose of this document. •
Arid Lands Administration [Arid_Lands_Administration Implements the Pastoral Land Management and Conservation Act [1989] Administers pastoral (42 year) leases Supports the Pastoral Board
•
Resource Inventory [Resource_Inventory] Maps to land system level (landform, geology, soils, vegetation) Provides the bio-physical basis for later lease assessment and monitoring work Held within a GIS database
•
Lease Assessment Program [Lease_Assessment_Program] Describes vegetation and soil resources Identifies issues and strategies Assesses land condition [Land_Condition_Index] Assesses land condition using remote sensing? Establishes monitoring sites Produces paddock plans and land system maps Estimates carrying capacities Produces Lease Assessment Overview Reports [Lease_Assessment_Overview_Reports]
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•
Rangeland Monitoring [Rangeland_monitoring] Permanently pegged photographic sites Records vegetation composition and density Rates rangeland condition and soil erosion type/extent Approximately 5,500 sites established Uses remote sensing to monitor cover and resilience in northern leases
•
Lease Inspection Program [Lease_Inspection_Program] Addresses issues identified at Assessment Identifies any new issues Negotiates land management strategies with lessee Revisits monitoring sites to determine trend
•
Biodiversity and nature conservation [Biodiversity_and_nature_conservation] Biological Survey of South Australia
•
Databases [Databases] GIS of infrastructure etc Photopoint database Stock Return Database Paddock database - description of identified land management issues Biological Survey of SA database
Arid lands administration In South Australia, the Pastoral Board administers the pastoral rangelands through thePLMCA [1989]. The Board is required to ensure that the Objectives of the Act (Section 4) are enacted: (a) to ensure that all pastoral land in the State is well managed and utilised prudently so that its renewable resources are maintained and its yield sustained; and (b) to provide for(i) the effective monitoring of the condition of pastoral land; and (ii) the prevention of degradation of the land and its indigenous plant and animal life; and (iii) the rehabilitation of the land in cases of damage; and (c) to provide a form of tenure of Crown land for pastoral purposes that is conducive to the economic viability of the pastoral industry; and (d) to recognise the right of Aborigines to follow traditional pursuits on pastoral land; and (e) to provide the community with a system of access to and through pastoral land that finds a proper balance between the interests of the pastoral industry and the interests of the community in enjoying the unique environment of the land. To do this, the Board carries out a number of functions. It liaises with Pastoral Soil Conservation Boards and individual lessees over the land condition assessment data provided to it by the PIRSA Pastoral Program. The Board is able to set land management and lease conditions on individual leases and is required to ascertain the capacity of each lease to carry stock. If necessary the Board has the power to require a compulsory muster of livestock to verify stock numbers. Once the lessee has accepted any conditions arising from the Board, it SA_Range monitoring & assessment activities (Ver1).pdf Page 12
has the power to grant a 42 year term lease, with a 14 year review period. The Board can also require actions to be taken by lessees such as destocking or provision of a property management plan. The Pastoral Board also has responsibility for dealing with public access issues, reference areas, and heritage agreements, administering pastoral lease rentals, ensuring effective information flow between pastoral lessees and interested community and other groups and considering proposals for alternative enterprises and uses of pastoral land. Soil Conservation Districts, and their attendant Pastoral Soil Conservation Boards provide a useful regional structure for arid lands administration. The Districts tend to be based on a combination of major land types combined with pastoral enterprise type.This regionalisation is frequently used by the Pastoral Board and much of the lease assessment activities take place on a Soil Conservation District basis. Soil Conservation Districts are established under the Soil Conservation and Land Care Act [1989].
Figure 1. Pastoral Soil Conservation Boards in South Australia
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Resource inventory The pastoral rangelands of South Australia have been mapped into land systems (Table 2). While the land system mapping was completed on a Soil Conservation District (SCD) basis, the mapping has now been joined to create seamless coverage for the pastoral lease region of South Australia. In some areas, land system mapping is very detailed. In other areas, the mapping has been done at a coarse scale in order to provide maps in time for the Lease Assessment requirements of the PLMCA to be met by the end of 2000. The mapping and associated documentation provides a general overview of the land system, indicating the extent, major characteristics and geology. The various units within each land system are described in terms of landform, soil type and vegetation. A profile diagram is used to show how the land system is comprised of its land units. The table below (Table 1) lists the source and scale of data for each SCD.
Table 2. Summary of resource inventory work in South Australia’s pastoral rangelands. Soil Conservation District Kingoonya
Gawler Ranges
North East
Mapping method
Mapped by
Comments
Mapped from rectified hard copy if Landsat TM imagery on :100,000 scale map sheet basis
Pastoral Lease Assessment Program (PLAP)
The western portion was mapped in more detail to suit other project needs. Boundaries revised as part of District Plan revision.
As above (Yardea 1:250,000 map sheet originally mapped by Faithfull and Stewart 1987) As above
PLAP
Eastern Districts Flinders Ranges Marla-Oodnadatta
Marree
PLAP PLAP
Mapped using unrectified Landsat MSS imagery at 1:250,000 scale
Mapped using unrectified Landsat MSS imagery at 1:250,000 scale
PLAP Soil Conservation Board with assistance by the PLAP.
Broad pasture types match NSW types Broad pasture types match NSW types Very broad scale mapping for the District Plan. More recent Landsat TM imagery classification and digital geology are available for half this area. Some areas will have detailed mapping in 2000 following revision of the District Plan and incorporation of Biological Survey mapping units.
The Landscape Units used are based on The Environments of South Australia (Laut et al. 1977)
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Figure 2. Major Landscape Units on South Australian pastoral leases (after Laut et al. 1977).
Lease Assessment Program summary Lease Assessment Reports Lease Assessment Reports are prepared for individual leases before being submitted to the Pastoral Board in district batches. They contain an assessment of the condition of the land, factors that limit the capacity of the land to carry stock, identified land management problems within each paddock and suggested strategies that might be adopted to alleviate these problems. The individual lease reports are confidential to the Board and the lessee. However, publicly available District Overview Reports were produced for the Kingoonya (Anon 1991) and Gawler Ranges (Tynan 1995) Soil Conservation Districts that summarised general findings from the assessments within a District and provided aggregated Land Condition Index data. There are no plans to produce similar Overview Reports for the other pastoral SCDs, although aggregated data have been supplied to the Soil Boards for consideration in their District planning. The Lease Assessment Reports are comprehensive, containing: • GIS based map coverage; • a report on each paddock of the lease; • a summary of the Land Condition Index scores; and SA_Range monitoring & assessment activities (Ver1).pdf Page 15
•
baseline monitoring data
The GIS coverage contains vector and point layers: waterpoints (dams, tanks, wells, bores, troughs, watering holes), fencelines, tracks, roads, pipelines, railways, transmission lines, lakes, saltpans, claypans, water courses, floodplains, buildings, yards, land systems, lease boundaries, administrative boundaries and monitoring photopoints. Raster layers include rectified imagery, resilience and grazing gradient analysis (where it exists). Three types of map coverage can be produced from this: 1) lease plans, 2) land system maps over individual leases or the whole district and 3) potential grazing impact zones over individual leases or the whole district. The report on each paddock contains an assessment of land condition, highlighting areas of concern sufficient to be identified as specific land management issues and suggested measures to manage these areas. A Land Condition Index summary is prepared for the lease (in areas where the LCI is used). Each major paddock has a fixed photopoint installed where vegetation, landscape and soil data are collected. The assessment of land condition has three major components: • a restricted random sampling method, referred to as the Land Condition Index (LCI) is used to assess the condition of each lease relative to all other leases in the district. The LCI is used on the majority of southern leases, but not north of the Dog Fence; • a monitoring baseline is established with the use of fixed photopoints where ecological data are collected; • a paddock based assessment that is largely subjective and involves a description of the paddock and the identification of land management issues. A major task of the assessment process is the updating (using GPS) of old hand drafted lease maps with computer generated maps within a GIS. The LCI approach is not used in the northern cattle country due to the more seasonally driven (ephemeral) nature of the vegetation communities. However, photopoints are established and a subjective paddock based assessment is made. Remote sensing (Grazing Gradient) technology is used on some northern leases (MarlaOodnadatta SCD) to determine areas which show a difference between actual and potential vegetation response to years of good rainfall. These areas can then be mapped out as exhibiting poor function.
Land Condition Index (used on the majority of southern leases) Summary of the LCI On most of the leases in the areas south of the Dog Fence, the Land Condition Index (LCI) (Lange et al. 1994) is used as the primary assessment of land condition. The LCI procedure complements site based monitoring by providing a means for deriving an objective estimate of the current relative overall condition of each of the leases in a Soil Conservation District (SCD). SA_Range monitoring & assessment activities (Ver1).pdf Page 16
The LCI is based on the condition rating of about 80 - 100 sample sites within each lease. Assessments are made into one of three classes; 1) high disturbance, 2) moderate disturbance and 3) low disturbance (Box 1). These classes are precisely specified for each component of each pasture type within a district. Under the Act, the optimal condition for the land is one that maintains the indigenous plant and animal life. This is an important point to note, since it suggests that the LCI is more closely related to the maintenance of biodiversity than to pastoral production or even landscape function. In practice, the maintenance of the indigenous species, pastoral production values and landscape function are closely related for many of the pasture types. The disturbance categories are mostly based on the presence, absence and abundance of perennial plant species, the level of grazing and browsing of palatable species, and some consideration of soil surface condition. By their definition, the condition classes provide an inherent assessment of the likelihood of the vegetation community to return to something like undisturbed condition. For example, sites in Class 1 condition are unlikely to recover, while those in Class 2 have the potential to recover under sufficiently benign management. A weighted average condition index is determined for each lease by multiplying the percentage of sample points for each condition rating by the rating (Box 2). This gives a value for each lease of between 100 (all sample points severely disturbed) and 300 (all sample points assessed as low disturbance). The LCI approach is not used in the northern cattle country due to the more seasonally driven (ephemeral) nature of the vegetation communities. However, photopoints are established and a subjective paddock based assessment is made.
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Box 1. Example of condition class descriptors used in the Land Condition Index. PASTURE TYPE:
1. Chenopod shrubland
COMPONENT:
(d) Casuarina pauper / Maireana sedifolia - Blackoak/bluebush on hard limestone soils east of Burra.
DESCRIPTION: Woodlands dominated by sparse to dense blackoak with very prominent pearl bluebush understorey. Diverse canopy species include bullockbush, sugarwood, mulga, weeping emubush, plumbush and weeooka (Eremophila oppositae.). Understorey is dominantly pearl bluebush with some Senna spp and pinbush wattle, but numerous other species can be present, few of which are of extensive cover. Nealie is a common element on Mutooroo Station. SOILS: Deep calcareous earths with sandy loam to loamy topsoils grading to clay loam subsoils. Calcrete at depth, with calcareous nodules at the surface in some places. In undisturbed areas, the surface carries a thick and extensive cryptogamic crust comprising mosses, diverse lichen and blue-green algae. OCCURRENCE: In the south of the district and found only on Lilydale and Mutooroo Stations. It occurs extensively through Eastern Districts. CONDITION CLASS DESCRIPTORS Class 3: Overstorey species ungrazed to moderately grazed (no level browseline on overstorey) and no grazing of bluebush; palatable shrubs ungrazed or lightly grazed. Regeneration of overstorey or of palatable shrubs. Crown Separation Ratio (CSR) between 3 and 6. Cryptogamic crusts thick and continuous; footprints but little padding. Class 2: Bluebush ungrazed or lightly grazed, and overstorey species heavily grazed with level browseline. Soil surface has minor padding/tracking but generally covered with cryptogams including lichen, algae and moss. Palatable shrubs lightly grazed to moderately grazed. Regeneration of any palatables moderately to heavily grazed. Class 1: Canopy species with well evident browselines and bluebush moderately to heavily grazed, mostly dead or reduced CSR 1-2. Palatable shrubs if present with heavy grazing impact. Cryptogamic cover discontinuous, lacking lichen, mainly bare or with only algal crust. Turpentine and/or Senna artem. petiolaris CSR 3-5. The uniformity, abundance and extent of the blackoak and pearl bluebush disguises a strong heterogeneity of most other shrubs and a few of the overstorey species relative to the pearl bluebush, most of the overstorey species are preferred grazing (sugarwood being the least palatable) as are most of the shrubs. The most palatable shrubs occur in discrete patches (quite small in places) and their absence need not be considered indicative of lesser condition.
Overstorey species include: blackoak (Casuarina pauper) mulga (Acacia aneura) bullockbush (Alectryon oleifolium) sugarweed weeping emubrush weeooka (Eremophila opposite) plumbush
Shrubs onclude: * bladder saltbush (Atriplex vesicaria) * bitter saltbush (A. stipitata) * low bluebush (Maireana astrotricha) * spotted emubush * spiny goosefoot (Rhagodia ulicinum) * silvertails ) * cassia (Senna sturtii or coriacea) * spiny fanflower (Scaevola spinescens) * scotia bush (Eremophila scoparia) * jointed native cherry bluebush daisy (Cratystylis conocephala) mallee bluebush native boxthorn wait-a-while spinebush
* shrubs which can be considered as palatable
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The LCI for each lease is derived from the weighted average condition score (Box 2). The LCI has an upper limit of 3.0 (all sites with low disturbance) and a lower limit of 1.0 (all sites severely disturbed). Box 2. Example Land Condition Index assessment and calculation. Note: more detailed descriptions of each of the condition classes for each of the vegetation components are provided in documents such as that provided in (Box 1) for: 1(d) Casuarina pauper / Maireana sedifolia Blackoak/bluebush on hard limestone soils east of Burra. Code
Vegetation / component type
Condition Class 1 (highly modified; indicator species absent or nearly)
Chenopod shrublands 1(a) Maireana astrotricha / Atriplex vesicaria plains and low hills 1(c) A. vesicaria plains and low hills 1(d) M. sedifolia calcareous rises 1(g) M. pyramidata calcareous flats and watercourses Woodlands and low woodlands 2 (i) Acacia aneura / A. tetragonpphylla / Eucalyptus / Casuarina / Myoporum etc 2(j) Callitris glaucophylla / Eucalyptus intertexta hills of central Flinders Ranges Hummock grasslands 4(a) Triodia spp. hills with or without scattered trees or shrubs Annual / ephemeral communities 5(d) Enneapgon shaley hills Shrublands 6(d) Mixed shrublands (Eremophila / Acacia / Dodonaea etc) Tussock grasslands 7(b) Cymbopogon
Condition Class 3 (near pristine and with indicator species intact)
8 19 1 1
5
10
3
3
5
3
2
2
2
8
1
14
7
5
1
1
52 50.9%
3 35 34.3%
Unclassified TOTALS PERCENT OF TOTAL SAMPLE
Condition Class 2 (main structure intact, indicator species grazed)
13 12.7%
The Land Condition Index is calculated thus: The rating score (1, 2, or 3) is multiplied by the percent of samples that received that score. (3 x 12.7%) + (2 x 34.3%) + (1 x 50.9%) = 157.6 The sum of these is then divided by 100. 157.6 / 100 = 1.6
The Land Condition Index for this lease is 1.6
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Three land condition classes The Land Condition Index is based on the rating of a number of restricted random samples on a lease. At each sample site, an assessment of the land condition is made into one of three classes: • Class 1 - high disturbance • Class 2 - moderate disturbance and, • Class 3 - low disturbance Level 3 represents low disturbance and is generally found some distance from water points. It serves as a benchmark for the potential species mix for a particular vegetation community. Level 2 has the potential to revert to Level 3, since the key palatable species are present, although in reduced densities. The soil surface may be disturbed with slight erosion but seedlings can still colonise the area. Level 1, where disturbance levels are high, may not show any evidence of the original vegetation remaining and the only indicator may be the soil type. Often, erosion is severe and the re-establishment of desirable species would require mechanical treatment and a seed input. Evidence of previous vegetation communities is generally exhibited as fence-line contrasts, some of which are clearly visible on satellite imagery.
Basic assumptions of the LCI The LCI uses criteria based on some fundamental and somewhat contentious assumptions which are: 1. That it is possible to determine the current condition of the vegetation and soils of each sampling site relative to its likely appearance prior to the use of the area for domestic stock grazing. 2. That by sampling along the road and track network on a lease it is still possible to come up with a meaningful measure reflecting average condition of the whole lease area. 3. The method can separate out the effects of season from other factors affecting vegetation condition The LCI approach was subject to a peer panel review including eminent rangeland scientists from Australia and overseas. It has been published as Lange et al. (1994).
Preparation of the LCI guidelines for each Soil Conservation District 1. For each SCD a Land Condition Index Technical Manual is produced by senior assessment staff for each Soil Conservation District. The Manual details the main Pasture Types and components found in the district along with photo standards for each LCI Class. For example, within the Chenopod Shrublands Pasture Type, one component is called Casuarina pauper / Maireana sedifolia - blackoak / bluebush on hard limestone soils east of Burra (Box 1). This description identifies in very general terms the main indicator species of grazing significance as well as the main topographic elements it occupies. Each component also includes “condition class descriptors” as well as photos of typical examples where available. The views of local lessees with experience in the District are also sought to refine the criteria (done in the Gawler Ranges SCD at least). Field days with lessees and managers from within the Soil Conservation District are held to explain the technique. SA_Range monitoring & assessment activities (Ver1).pdf Page 20
2. Assessment staff were taken on a calibration trip at the start of lease assessments in the district, and trial traverses were undertaken as a group training exercise in gaining familiarity with the pastures in the district. 3. Before an assessment of a particular lease, the total traverse distance likely to be covered is determined from existing maps. 4. A computer random number generator is used to specify a statistically valid number of mileage readings which will be the sampling points on the traverse (usually 80 to 100 points). 5. As the assessor travels around the tracks of the lease, or along fencelines, the pasture type is assessed at exactly the pre-determined mileage point. 6. At each site the pasture type and component is specified, a condition score given (either a 1, 2 or 3) and a photograph taken. The main criteria used to determine the score are written in the field notebook , and the site can be relocated if desired as GPS coordinates are now noted. 7. Back in the office, any doubtful sites are peer-reviewed by senior staff prior to the data being entered. Like any field based survey method, there are many judgements which need to be made in process of making the decision. Most of the common ones are covered in the field manuals in order to minimize the possibility that different field techniques by assessment teams may result in significant differences in the average site and thus lease condition rating.
Remote sensing (Grazing Gradient) on northern leases (The following has been extracted, with some minor changes, from Brook et al. 2001) On northern leases, the LCI is not used. On these leases, the Grazing Gradient technique is used to for lease assessment. The technique compares vegetation cover levels (in relation to distance from water points) before and after large rainfall events. The pattern of the grazing gradient indicates change in vegetation cover due to grazing and is interpreted to determine the condition (landscape function status) of a particular landscape type. A lack of vegetation response following these rainfall events may indicate reduced landscape function. The grazing gradient method was developed by CSIRO in Alice Springs (Bastin et al. 1993; Pickup et al. 1994; Bastin et al. 1998). A major benefit of using remote sensing is the spatial coverage that is provided, enabling all areas within a rangeland property (and pastoral region) to be covered. Ground based observations are generally limited to areas adjacent to vehicular tracks and therefore sample only a very small proportion of a property. Imagery comprises digital data that is readily analysed through computer software and can be combined with other digital data sets through a GIS. There is also a good archive of imagery that permits analysis of past events - important for detecting change in arid rangelands. Through analysis of a time series of Landsat Thematic Mapper (TM) images, cover changes with distance from water points (grazing gradients) are plotted to determine the relative impact of grazing. Grazing gradient plots of vegetation cover following major rainfalls indicate where changes in landscape function may have occurred. Persistent wet-period gradients indicate reduced potential of landscapes to grow vegetation cover as a result of past grazing. This reduction could be due to loss of desirable perennials, accelerated erosion, degradation of soil SA_Range monitoring & assessment activities (Ver1).pdf Page 21
quality (eg. reduced infiltration and moisture holding capacity, loss of plant nutrients) and other components of landscape function. An example of a grazing gradient plot is shown in Figure 3 for the Paisley land system. This shows a steep wet-period gradient of increasing cover close to water points suggesting a reduction in landscape function close to water. Thresholds of change are indicated by abrupt changes in vegetation cover levels (inflection points). In the example of the Paisley land system, the inflection point occurs at approximately 1.5 km from water, beyond which distance cover level stabilises, indicating that grazing impact becomes relatively minor. Areas remote from water and beyond the normal grazing range of stock (greater than 8 km) provide an indication of the natural productive potential of the landscape. Figure 3 also shows the relative change that may be attributed to grazing compared to background climatic change. A spatial representation of cover levels and their response to rainfall is also used to assess land condition (Figure 4). Vegetation cover levels in the PD54 layer (an index of cover) are represented by red (lowest cover) through to orange, yellow, green, light blue and dark blue (highest cover). On the right hand side of Figure 4 image the gibber plain areas have much more yellow and green (lower cover) than on the left where blue is predominant (higher cover). Trees along drainage lines with relatively dense canopies show up as dark blue. These contrast strongly with the surrounding plains (depicted in light blue and green) that have less cover. Areas naturally bare of cover or where there has been a substantial reduction in cover through grazing appear as red. For example, the large red patches on the upper right hand side of the PD54 image are alluvial flats along a broad treeless drainage line adjacent to the permanent water point shown by the black square. The PD54 image shows the extent of the reduction in perennial vegetation cover in this region.
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Figure 3. Grazing impact in the Paisley land system occurs within 0-2km of waters. The permanent decrease in cover in these areas suggests that landscape function has been disrupted and the landscape has lost its ability to produce vegetation close to water. Areas beyond 2km from water (i.e. where average cover level stabilises) provide a benchmark of cover that is relatively unaffected by grazing for this land system.
250 Benchmark of cover remote from grazing
Pd54 Cover Index
225 Inflection point
200 175 150
Background change (seasonal change in vegetation)
125 100 0
2
4
6
8
10
Distance from w ater (km ) 1988
1989
1997
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Figure 4. An image using the PD54 cover index. Created during a dry period, the image shows a contrast either side of a north-south fenceline.
Lease Assessment Overview Reports While individual lease assessments are confidential to the Pastoral Board and the Lessee, aggregated information can be made available at the district, vegetation type or other regionalisation. For the Kingoonya (Anon 1991) and Gawler Ranges (Tynan 1995) SCDs Overview Reports were prepared once individual lease assessments for each District were complete. Such overviews are public documents and provide a useful level of aggregation for reporting at a District to State scale.
Contents of Lease Assessment Overview Reports Lease Assessment Overview Reports such as that for the Gawler Ranges SCD (Tynan 1995) provide information on: • Geology and landscape (land systems, soil and vegetation relationships) • Climate • History (early explorers, pastoral development, production, water, rabbits, dingoes) • Recent pastoral production (lease map, infrastructure developments, recent stock numbers, stock production) • Lease assessment methods (Land Condition Index, Robustness Index, baseline monitoring photopoints, paddock based assessment, priority paddocks, lease assessment reports) • Lease assessment results for the District (overall condition of land and vegetation types, indicators and condition criteria for each vegetation type, factors influencing land condition, land mangement guidelines) SA_Range monitoring & assessment activities (Ver1).pdf Page 24
• •
Factors that affect the capacity of the land to carry stock (management practices, historical usage, watering points, number of stock per water, timing and period of grazing, total grazing pressure) Conservation issues
The following type of information is provided in the Lease Assessment Overview Reports, using the Gawler Ranges report (Tynan 1995) as an example.
Background and context The 57 pastoral leases of the Gawler Ranges Soil Conservation District cover approximately 41,500 km2 and have been subject to domestic stock grazing and other agricultural activities for over 140 years. About 324,000 sheep and 2,461 cattle (1994 figures) are carried over a watered area (5 km radius from permanent water) of 30,059 km2 (i.e. 72% of the area is watered). Land condition The lease assessment process in the Gawler Ranges examined over 1,200 padocks during 1992 and 1993. A total of 3,611 sample Land Condition Index (LCI) observations were made: • 16% had high disturbance levels (LCI Class 1), • 32% were moderate (LCI Class 2) and, • 52% had low disturbance levels (LCI Class 3) An example of the pasture type condition criteria used in the LCI assessments is shown in Box 1. The Land Condition Rating can also be summarised by vegetation type (Table 3).
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Table 3. Percentage of condition rating observations for pasture type communities within Gawler Ranges SCD leases. Class 1 is highly disturbed, Class 3 is minimally disturbed. Such tables provide data on the relative condition of different vegetation types but also indicate the relative proportion of each vegetation type sampled within each District. They do not necessarily represent the relative areas of each vegetation type within the District. Taken from Table 8, Tynan (1995). LCI Rating (%) Class 1 Class 2 Class 3
Vegetation type community Chenopod shrublands 1(a) Treeless plains 1(c) Samphire / saltlake 1(d) Calcareous plains 1(e) Arcoona Tableland 1(g) Blackbush watercourses 1(h) Gawler Range alluvial valleys
Total
Total
0.30 0.61 1.88 0.30 2.08 5.23 10.41
0.64 1.14 9.11 0.30 6.78 5.20 23.17
5.56 6.48 16.17 4.68 9.52 1.41 43.83
6.51 8.22 27.16 5.29 18.38 11.85 77.41
Total
0.36 3.99 0.33 0.00 4.68
1.30 5.34 1.14 0.39 8.17
0.55 6.17 0.28 1.16 8.17
2.2.1 15.5 1.74 1.555 21.02
Total
0.61 0.61
0.58 0.58
0.36 0.36
1.55 1.55
TOTAL
15.70
31.92
52.36
100.00
Low woodlands 2(a) Mulga grasslands-sandy 2(d) Mallee / blackoak 2(e) Native pine on dunes 2(f) Mallee / spinifex on dunes
Hummock grasslands 4(a) Gawler Range rhyolite hills
Photopoints A total of 1,043 photopoint monitoring sites were installed as part of the lease assessment process.
Lease inspections and priority paddocks A total of 109 paddocks were classified as priority paddocks, requiring priority action to address land management issues.
District level land management issues A number of factors such as droughts, the lack of ground water, feral and native animal grazing competition, predation by dingoes and financial hardship have all led to inappropriate grazing practices since settlement up to 140 years ago. This has led to substantial alteration of the SA_Range monitoring & assessment activities (Ver1).pdf Page 26
productive landscales in the District. In early years, some of the valleys were also cultivated and cropped. Recent changes in land management, such as reduced stock numbers on waters and the ability to transport stock during drought largely removed the concentration of large numbers of animals around watering points. Water supply is still a major limitation to the carrying capacity of the District, with most supplies being surface catchment in dams. Feral goats remain a problem in some areas, and together with rabbits and kangaroos, contribute to raising the total grazing pressure.
Pastoral Program photopoint monitoring sites Summary The assessment process outlined in the PLMCA [1989] is also required to provide an effective monitoring system for each lease. Changes in arid areas can be slow and difficult to detect. Taking photos from fixed sites (photopoints) is one method that allows these changes to be detected. Monitoring sites in South Australia are generally referred to as photopoints. These are permanently marked sites at which photographs are taken and information on vegetation and soils collected. Most permanently stocked paddocks on Pastoral Leasehold lands have at least one photopoint. Photopoints indicate long terms trends in the land at the individual site. However, each site has a unique set of characteristics and may not be representative of the whole paddock. At the lease scale, the photopoints spread across the lease (approximately 20 per lease) should be considered to represent a sensibly stratified sample of rangelands on that lease. The establishment of a complete assessment site, including a Jessup transect, takes approximately 60 to 90 minutes, depending on vegetation density and complexity. The complete installation of 5,500 photopoints was finished by the end of 2000 (Figure 5). There is no firm schedule for the reassessment of the 5,500 photopoint monitoring sites already installed. The Pastoral Board’s guidelines state that “A thorough pastoral inspection / monitoring trip including re-visiting of every photopoint on a lease before or by each 14 year review period will comprise an adequate reassessment for the purpose of Section 25 of the Pastoral Land Management and Conservation Act 1989.”
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Figure 5. Location of photopoint monitoring sites in South Australia
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Site stratification At the regional level, sites are installed so as to have at least one site in every permanently stocked paddocks (of reasonable size) on Pastoral Leasehold land. Sites are also installed on Conservation Reserves and National Parks. At the local scale, sites are generally located around 1.5 km from permanent water in sheep country and around 3 km in cattle country. Ideally, monitoring sites are located in the most typical vegetation type within the paddock. Where there are several vegetation types, a type which will give a good indication of grazing impact is chosen. The site should be uniform with respect to vegetation, soil, slope and aspect. So that sites can be readily relocated, they are generally installed near established tracks.
Attributes assessed at photopoints Site details The following list of attributes is recorded at each photopoint (Table 4);
Table 4. Attributes recorded at each photopoint. Attribute Station Name Paddock Name Site Number Last Assessment Date Site Location
Easting / Northing Waterpoint Land System Name Dominant Species Geological formation Rock Type Landform Soil Textures Site Comments Site Vegetation Site Condition Estimate Erosion Crown Separation Ratio (CSR) Shrub Count
Comment As per paddock plan. Identical to that on site disc and paddock plan. Date of last visit. Description of location, typically based on distance and direction from a known point such as permanent water. Australian Mapping Grid coordinate as determined by GPS. Name of waterpoint and distance to it As per District Land System Map. Up to four dominant species. Taken from SA Department of Mines and Energy maps. Type of rock outcrop. Landform pattern. Proportion of sand, silt and clay in each horizon. Comments recorded at each site. A vegetation list is compiled for each site . Site Condition Rating Site_Condition_Estimate. Type and severity Erosion_type_and_severity. Cover estimate using CSR (Crown_Separation_Ratio). Based on Jessup transect (Jessup_transect) and expressed as an actual count in 400 m2 transect. This provides an indication of shrub densities and age structures (adult and juveniles). Ongoing assessments indicate the trend of these populations.
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Jessup transect The Jessup transect method measures the density (shrubs/area) and frequency of perennial plants at sites where perennial cover occurs, i.e. chenopods, other shrubs and tussock (perennial) grasses. Counting age classes of shrubs (adult/juvenile) gives further information on population changes. Monitoring over time provides an indication of recruitment trends. Recording is based on all perennial shrubs within the transect being recorded by species and age class (adult/juvenile). If the base of the plant is in the transect it is counted. If the foliage only is in the transect it is not counted. Jessup transects are permanently marked and comprise: • transects 100 m x 2 m x 2 m (Figure 6) • recordings separated into 10 m x 2 m blocks (Figure 6) • species identified • less than 10 cm high and/or non woody base = juvenile • more than 20 individual juvenile bushes or perennial grasses per 10 m x 2m block = 20+ recording
Crown Separation Ratio This is a visual estimate of plant cover . It is the average distance between crowns (the area the plant takes up if viewed from above) divided by the average size of the crown (Table 5). In the field, this means visualising how many crowns of a given plant species can be fitted in between the distance to the nearest neighbour of that species on average over the site. The classes are as follows:
Table 5. Crown Separation Ratio classes. Class 1 2 3 4 5 6 7
Term Present Isolated clumps Isolated Plants Very Sparse Sparse Mid dense Closed or dense
CSR 20 6-20 1-5 0-.9 0
Field Criteria