|Pressure State Response Indicators need to be looked at in linked sets. They link physical indicators of change with socio-economic indicators of pressure and political/institutional indicators of response.|
Why is it happening? Is there overgrazing? If so, what has caused it?
Artificially Increased Grazing Pressure - Poorly placed resources such as watering points can result in overgrazing of some areas and the under-utilisation of others.
Reduction in Mobility - a change in the freedom of movement of livestock is often an underlying cause of overgrazing. Historic records may be compared with present information on herd and herder mobility. Consultation with stakeholders will provide good information.
Reduction in Communal Grazing or Reduction in Available Area - often linked to the conversion of the better range areas to arable production in response to increasing human populations and/or to an increased need for cash crops. Information may be available through the same remote sensing data sets as used for vegetation cover. Additional information may be available on land registration from land authorities. And again consultation will be an essential part of the process of establishing the extent of the problem.
Shift in Herd Composition - e.g. cattle to small-stock, will inevitably change the nature of the grazing / browsing pressure.
Additional Contributory Reasons: To what extent is increase in human population numbers a contributory factor leading to overgrazing? Are there any political or institutional reasons for overgrazing to have taken place? For example, have subsidies resulted in any market changes? Has a general deterioration (or increase) in the quality of transportation facilities resulted in a changed market for livestock products?
Change in Species Composition and Abundance - invasion of weed species and loss or reduction of key or important indigenous species. This may be recognised by local herders and/or botanists from a local institution. The analysis is likely to be highly subjective unless previous survey work on species composition and distribution (using the same analytical techniques) is available. This analysis is relatively low cost and can be combined with discussions with herders and other stakeholders on pressure / state indicators as long as an interdisciplinary team can be put together for the fieldwork. The use of fixed point photography can contribute to a monitoring programme over a number of years. Similarly, there may be a change in the abundance, distribution and species composition of wildlife.
Change in Rangeland Quality - Simple techniques of classification can rapidly build up into an overall assessment of rangeland condition without the need for extensive and time consuming collection of large amounts of specialist data. An example of assessment of range condition for horses in Iceland serves to illustrate the potential of these methods.
Change in Climate - This may have an effect on rangeland productivity independent of human induced pressures. Changes in conditions during the growing season may be indicated by time series of climate data, which are generally readily available,. Examination of a time series data set should indicate whether a change in weather patterns is a potential contributing factor to land degradation. Time series of satellite data may also provide evidence for change, especially NOAA AVHRR imagery processed to provide a vegetation index (e.g. NDVI). However, the most important use of these data sources will be to emphasise and to quantify the normal annual and seasonal climatic variation, i.e. the variability from year to year.
Indications of Accelerated Erosion - field surveys can establish that accelerated erosion is taking place through the identification of key erosion features such as root pedestals. Again this is subjective unless it can be compared to previous survey work, but still has the advantage of allowing discussion with herders and other stakeholders. Additional data on sediment load in stream may also be available from hydrological institutions, indicating changes in erosion. And again the assessment should not be a major cost.
Uneven grazing distributions can, where practical, be reduced by changing
paddock shape, or through fenceline relocation (including complete removal
and the addition of new fences), paddock sub-division or by the addition,
relocation or closing of watering points. Models of animal distribution
can assist in the application of these decisions once they are validated
for the particular environment in which they are applied.
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