Application of GIS in vegetation management planning – opportunities for landholders in the southern brigalow belt Qld
There is increasing recognition of the need for geographical information systems (GIS) in vegetation management planning at both the property and catchment scale. This paper will outline the process used in the formation of both property scale and catchment scale vegetation plans and the opportunities they present to landholders. Current vegetation plans encompass issues such as soil mass movement, soil sodicity, biodiversity conservation, soil salinity and grazing management. The representation of these issues in a GIS environment using appropriate data sets has increased the effectiveness and accuracy of vegetation planning in the region. Likewise it has increased the opportunity for landholders to plan development in a way that both protects their resources and their investment in the long term.
Geospatial information such as satellite imagery and georefrencing of aerial photography allows landholders to view their property in a catchment and regional perspective, likewise it is an easier task for extension officers to point out landscape benefits of retention patterns.
Data sets such as cadastre, vegetation coverage, soils, topography and geology can mean the accumulation of knowledge in a more meaningful way to improve land use decision making for landholders in the region.
Combined with meaningful consultation and social processes, GIS and geospatial information is a powerful tool in the management of any resource, vegetation management is no exception.
Planning has been defined by Ramsay & Rowe (1995 in Boulter, Wilson, Westrup, Anderson, Turner & Scanlan (ed.) 2000) as the coordination of human activities with both natural and human resources.
So how do we do this? This paper details one approach that features GIS and the use of spatial information as a tool for education and action in rural landscapes.
Outcomes of Producing Vegetation Management Plans
1. Ensure productivity of landholders’ property is sustainable
2. To ensure natural resources are not degraded
3. To ensure values of nature conservation are maintained for future generations
4. Identifying current and future sustainability resources issues (eg. salinity) to incorporate rehabilitation solutions into vegetation plan.
Addressing Resource Issues
GIS is a tool used to aid in the decision making process for the management of our resources in a sustainable manner.
Resource issues are being addressed in a multidisciplinary environment at both a property and regional scale through the use of vegetation plans. The main resource issues incorporated into vegetation plans include:
- Biodiversity – biodiversity conservation is one of the most important resource issues that vegetation plans addresses as it attempts to deal with the decline in the variation of plants, animals and micro-organisms. Loss of biodiversity results from habitat loss, fragmentation, decline in remnant vegetation health and associated land degradation issues.
Conservation of biological diversity is incorporated into vegetation plans in the form of corridors linking remnant vegetation and riverine areas. It is critical that remnant vegetation and corridor widths be of an adequate size to ensure biodiversity values are conserved. Stream buffers are incorporated into the vegetation plans to aid biological diversity through conservation of riverine ecosystems and to provide natural corridors linking vegetation on a more regional scale. Also, to maintain biological diversity, vegetation plans should include adequate proportions of each regional ecosystem type present both at a property or regional scale. The system of vegetation classification in Queensland includes an attribute of conservation status. This is based on the amount of that vegetation type cleared compared to its former extent prior to European invasion. This vegetation status is a critical component in planning for conservation and rehabilitation.
- Land degradation – land degradation includes (soil structural decline, sheet, rill, gully and tunnel erosion), soil mass movement, salinity issues, soil sodicity, poor grazing management, native pasture decline, invasion of noxious weeds and pests and a decline in water quality.
Vegetation plans attempt to address these issues by planning the removal or replacement of vegetation in a way that minimises the potential for land degradation. Data sets such as geology and land type coverage are used to flag potential problems such as sodic soils.
Regional v’s property scale planning
Vegetation planning occurs either at a property or a regional scale. Although resource issues can be addressed at a property scale, it is often necessary for many issues (for example, salinity) to be dealt with on a regional scale to ensure their effective management. Likewise biodiversity values are greatly enhanced by vegetation planning on a regional or landscape scale.
The number of data sets available to us as GIS practitioners is increasing all the time, all have levels of usefulness relating to factors such as scale and not all of them are compatible all of the time. For this project we have drawn on existing data sets, made improvements to some and created others. These include
- digital cadastral database
- regional ecosystem data
- salinity point data
- threatened species point data
The use of GIS and digital datasets as mentioned above has application to both the property and catchment scale planning. Both are useful formats, however it is with catchment based planning that GIS and spatial information is most valuable.
South Myall Creek Catchment Group (SMCCG)
The SMCCG have been operating as a catchment based Landcare group for approximately four years. They have undertaken information collection exercises, awareness raising activities and on-ground works focusing mainly on soil conservation measures. With increasing awareness of the threat of dryland salinity and a desire to learn from the mistakes of other regions in the country the group decided some 18 months ago that they needed to produce a vegetation management plan with a fairly strong focus on salinity mitigation. Below is a description of the process the group used as it relates to the use of GIS and geospatial information.
- Current vegetation coverage for the area had only mapped remnants in excess of 5 ha and at least 100m wide. The first task was, using digitally registered aerial photography at 1:25000 scale, remnants as small as 0.5 of a hectare were mapped and ascribed a regional ecosystem code. By mapping to this scale the group was able to view many more opportunities for connectivity, conservation and remnant expansion to address salinity issues. An important result of this activity was an acknowledgement that whilst small remnants have diminished ecological value they have incredibly important cultural value in a highly modified landscape.
- The second task was to “discover” areas of land that already had a history of dryland salinity and record their change over time from landholders in the region. This was undertaken in a workshop format and all of the sites marked on a hard copy map of the catchment.
- These nominated sites were visited by landholders and technical staff to collect information on landtype, geology, vegetation type and landuse history, GPS waypoints were also recorded and the sites were traversed with an EM38 to gauge severity.
- By collecting this information, a predictive model of where salinity was going to occur in the future could be generated. By intersecting geology, vegetation types and landtype in a GIS environment, we were able to generate a risk map for the group. Likewise the group were able to target their investment in salinity mitigation.
- With the use of GIS and geospatial information the group were able to further target their activities by intersecting high risk salinity areas with larger remnants and remnants on land types that were seen to be responsible for recharge or susceptible to discharge.
- Calculations on remnant size, percentage cover in the catchment and conservation status has enabled the group to undertake some five kilometres of restoration and connectivity-based revegetation.
One important note is that this the technical process ran hand-in-hand with a social process based loosely on the Living Landscapes approach created by Greening Australia in the West Australian Wheat belt.
The Benefits of GIS to Landholders
Using GIS to complete vegetation management plans provides many opportunities for landholders to strategically plan development on their properties for the purpose of conserving their natural resources and ultimately, ensuring the long term productivity of their land.
1. Through the use of GIS, landholders can be provided with data that is spatially represented. This not only promotes a higher level of understanding concerning their resources but a greater interest in the sustainability issues facing their respective properties.
2. The use of aerial photographs and satellite imagery enables landholders to view their resources from a different perspective than otherwise available to them. Aerial photographs in particular allow landholders to study their property and resources such as vegetation in detail and hence make more informed decisions when planning development.
3. Datasets such as satellite imagery, aerial photographs, regional ecosystem types and streams data are all provided on larger scales than individual properties. This enables landholders to view how their property and its resources interact with other neighbouring properties and allows them to make resource management decisions based on a more regional scale. For example, landholders could ensure that corridors on their property links with remnant vegetation or corridors on neighbouring properties increasing biological diversity benefits.
4. GIS also provides property owners with the distinct advantage of being able to overlay different data sets in order to provide more information for more informed resource management decisions. Using GIS allows problem areas such as potential or current land degradation sites to be identified and spatially represented. This overlayed with other data sets such as regional ecosystems, streams data and imagery enables vegetation plans to be developed in a way which promotes the long term sustainability of resources.
5. The wide range of data sets available such as streams, vegetation coverage, soils, topography and geology data sets provides landholders with a greater depth of knowledge and allows them to make informed decisions regarding land usage and sustainability issues.
Benefits of Using Data Sets and Imagery to Vegetation Planning Officers
1. GIS is an effective tool that extension officers can use to aid landholders in developing vegetation management plans. It provides a visual means in which to demonstrate the location and extent of resources on properties giving landholders a greater awareness, understanding and interest behind the philosophies of vegetation planning.
2. GIS provides a method of planning which is more accurate, efficient and effective, ultimately producing an easier way to complete vegetation management plans that promote the sustainability of resources.
3. The ability to develop vegetation plans on a regional basis is made simple through the use of GIS and the variety of data sets available to resource management officers. This not only benefits natural resource management officers but promotes conservation values.
Maps, GIS and geospatial information are vital to vegetation management in south west QLD but as much as they are technical tools they are also extension tools and being GIS practitioners who work with landholders to conserve, plan and manage vegetation on a daily basis we have not lost sight of the fact that they are excellent extension tools. Graziers and farmers on the most part in the region enjoy looking at maps, and maps of their property with a whole swag of data over them increase their confidence in us and our relationship with them. In the end it is people’s attitudes and management approaches we are working with and GIS and geospatial information have assisted this process enormously.
Ramsay & Rowe (1995) in Boulter, S.L., Wilson, B.A., Westrup, J., Anderson, E.R, Turner, E.J & Scanlan, J.C. (ed.) (2000) Native Vegetation Management in Queensland: Background Science and Values, The State of Queensland, Department of Natural Resources, Indooroopilly.