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System Title |
4.8 Taranaki Regional Council Sustainable Land Use Classification |
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| Keywords | Sustainable land use classes; New Zealand Land Resources Inventory; Land Use Capability.; |
| Description | Eight 'sustainable land use classes' have been identified for the Taranaki
Region using the following criteria:
For each mapped area the 'sustainable land use class' indicates the most intensive physically sustainable land use possible on that land. Classes include:
The system has been designed to monitor the changes in land use within each class to provide a basis for assessing whether land use is becoming more or less sustainable. The allocation of land in the region to sustainable land use classes was made primarily according the LUC assessment presented in the NZLRI. Using criteria established for the recognition of LUC Units, supplemented by personal knowledge and experience, Manaaki Whenua Landcare Research and Taranaki Regional Council staff, allocated all LUC units to sustainable land use classes. A more detailed assessment was made of hill country LUC units. This was based on: an interpretation of research results from the Makahu District and and assessment of their applicability to other parts of the region; and limited aerial photo and field assessment of eroded areas and slope distribution within LUC units in representative parts of the hill country. As a result, several hill country LUC units have been divided between more than one physically sustainable land use, on the basis of slope. (O'Leary & Stephens 1986) For those monitoring sites which have historical data the following data can be generated on a site by site basis or as summary statistics:
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| Original Purpose | To monitor the sustainability of land use within the Taranaki Region. |
| Status | Work began in 1992 as a Pilot Project. Development, review and refinement of the technique through to 1996. |
| Organisations | Taranaki Regional Council Manaaki Whenua Landcare Research |
| Jurisdiction | Taranaki Region |
| Contact person/position & Address |
Director- Resource Management Taranaki Regional Council Private Bag 713 47 Cloton Road Stratford Phone +64 (6) 765 7127 Facsimile +64 (6) 765 5097 www.trc.govt.nz</> Peter Stephens |
| Available format | Digital and hardcopy maps illustrating sustainable land use classes. Digital Arc/Info GIS software |
| Access | |
| Geographical coverage | Taranaki Region |
Operational Specifications |
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| Scale of Operation | The classes are mapped at 1:250,000. |
| GIS Compatibility | Yes |
| Relationship between levels in the classification system | No hierarchy |
| Contributing databases/classification systems | New Zealand Land Resources Inventory |
| Contributing database GIS compatibility | Yes |
| Relationship with other classification systems and spatial frameworks. | Land Use Capability Classes |
| Relationship with other databases | N/A |
Current and emerging use for: |
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| Assisting with determining historic state/ baseline | No |
| Assisting with determining current state/ baseline | A 1994 baseline has been established with which further monitoring of land use changes can be compared. |
| Asssisting with scenario building and modelling of possible futures | Inherent in LUC Classification and this Sustainable Land Use Classification.
With intelligent use (i.e. taking into account underlying assumptions) of LUC and Sustainable Land Use Classification it is possible to predict the potential effects of land use changes in identified LUC units and/or sustainable land use classes. |
| Risk Assesment | A very broad form of risk assessment that can be used to target effort. |
| Monitoring site selection and sample design | The framework can assist in the selection of monitoring sites. The actual selection of representative monitoring sites for long term remote monitoring also involved the consideration of site specific information gained from aerial photographs. |
| Aggregating and reporting data locally, regionally and/or nationally | This is possible at the local and regional scales. |
Current use (who,level,why)
- Taranaki Regional Council uses this framework
User friendliness/public and decision maker understanding
- This framework is easy to understand.
Framework strengths
- This framework assists Taranaki Regional Council to measure progress in achieving more physically sustainable land use, particularly with respect to the eastern hill country.
- It is a cost effective method for monitoring land use sustainability, relative to alternative options such as physical soil sampling.
- The technique is repeatable, accurate, and could be adopted in other parts of New Zealand, given available remotely sensed data. (O'Leary & Stephens 1986).
Current limitations of framework
- It does not address wider (beyond land) sustainability issues such as the effects on aquatic habitats and so may provide a slightly misleading impression of sustainability in some cases.
Detailed Description
- Relationship of Taranaki Regional Council Sustainable Land Use Classes to NZLRI Land Use Capability Suites
Related LUC units were grouped in LUC suites. An LUC suite is defined as "A group of LUC units which, although differing in land use capability, share a definitive physical characteristic which unites them in the landscape." In Taranaki the primary factor distinguishing LUC suites is soil parent material (Fletcher 1987). LUC suites were also convenient groupings for consideration of sustainable land uses.
Spatial variability within LUC units is inevitable. This means that when accessing the suitability of LUC units for specified land uses, some parts of a mapped unit can be sustainably managed for a certain range of land uses but other, smaller, parts have either a smaller or a larger range of sustainable land uses.
So more than one sustainable land use is allocated to LUC units: a principal sustainable land use and up to 2 minor sustainable land uses. The principal sustainable land use is identified as the sustainable land use over at least 40% of the area of the LUC unit, usually between 45 and 75% of the area. The minor sustainable land uses are identified as sustainable over at least 10% and up to 40% of the area of the LUC unit: where 2 minor sustainable land uses are identified the first is usually sustainable over 20-40% of the mapped area and the second usually over 10-25% of the area.
In the hill country these proportions have been estimated by assessing the distribution of slopes and eroded areas within mapped LUC units.
Both principal and minor sustainable land uses are given in the LUC unit descriptions, but only the principal sustainable land uses are shown on the map.
- Special Problems of Assessing Sustainability in the Hill Country
Hill country LUC units tend to be more variable. For example, slopes in many hill country LUC units range from less than 20% to well over 40%. Also many hill country LUC units are mapped over an extensive part of the region. The environmental characteristics of the hill country are less well known than those of the Taranaki ring plain. The pastoral economy which dominates the hill country faces serious problems which are unique or much more significant than in other parts of the region. Access and infrastructure in many hill country districts is poor. Natural soil fertility is generally low and soil fertility levels have significantly declined in the last decade because of much lower rates of fertiliser application. This has excarcerbated weed revision which has always been a problem due to high rainfall and low natural fertility. Erosion has been a recurring problem causing direct production losses as well as significant damage to farm and rural infrastucture.
A number of trials in Eastern Taranaki hill country were conducted between 1984 and 1988. These trials have provided detailed information from 3 farms at Makahu, Pohokura and Tututawa, on the following topics:
- Pasture Production:
- seasonal and yearly variation
- distribution on hill slope
- effect of erosion
- recovery after erosion
- effect of fertiliser application
- in relation to sheep requirements
- Soil fertility Levels:
- seasonal and yearly variation
- effect of fertilizer application
- % distribution on (uneroded) hillslopes
Additional relevant research in the Makahu district in the last 5 years includes the following:
- rates of soil loss on forested and deforested slopes
- soil reformation after landslides
- distribution of soil depths and rate of geomorphic processes in different slopes
- effects of storms on different land use types
The key results have been used to guide planning of sustainable long-term land uses on different parts of the farm.
By combining erosion data (aerial extent and chronology of landslides) with pasture production data it is possible to obtain estimations of the reduction in production, with the years sinces deforestation, below a potential production level (assumes non landslide erosion and constant management).
At Makahu trial site these results apply only to LUC unit 6e23 where slopes are predominantly 28-30 degrees.
The relationship between soil loss and slope angle has been used to recognise 4 primarily slope-defined hillslope units. The slope related soil loss and pasture production rates of these units also enables the recognition of differences in sustainable land use (Blaschke et al. 1993), as follows:
H1. Slopes less than 28 degree have lost little soil deforestation; pastoral farming there can be continued indefinitely.
H2. Slopes between 28 and 32 degrees show a slow net soil loss since deforestation, but if they are managed carefully then pastoral farming can be sustained.
H3. Slopes between 33 and 42 degrees have lost significant soil since deforestation and it is likely that pastoral farming can be sustained long term.
H4. On the steepest land, over 42 degrees, rapid soil loss towards a new steady state soil depth has already occurred since deforestation; soil conservation measures are unlikely to be effective even on areas which are not eroded at present.
These four categories correspond to the sustainable land use classes of Drystock Grazing, Pasture and Trees, Forestry, and Protection. (Blaschke, et al. 1992; Hicks, 1996; O'Leary et al. 1996; Stephens et al. 1995).
References
Blaschke, P.M. et al. June 1992. Physically Sustainable Land Uses in the Taranaki Region: A Pilot Project. DSIR Land Resources, Contract Report: LC 92/27 prepared for Taranaki Regional Council.
Hicks, D. November 1996. Review of Sustainable Land Use Classification for Taranaki. Ecological Research Associates (N.Z.) Inc. for Taranaki Regional Council.
Stephens, P.R. et al. March 1995. Land-Use Monitoring in the Taranaki Region. Manaaki Whenua - Landcare Research, Contract Report: LC 9495/96 prepared for Taranaki Regional Council.