They tend to be clearer than negative memories. Conclusions from her research are that nostalgic yearning is especially likely to occur during periods of transition and uncertainty, like maturing into adulthood or aging into retirement.
She has also found that technological progress can elicit nostalgia.
Against the current background of instability, transition and uncertainty, as well as technological progress, it is not surprising that people want the landscape to remain the same as it used to be.
The Mackenzie Basin is a prime example.
Research published by Landcare scientists has shown that in pre-human times, the driest areas supported scrub conifers, small-leaved shrubland, kōwhai and kānuka, with grassland or herbfields. Forests of Mountain tōtara, silver beech and celery pine covered the wetter, higher slopes.
By the 15th Century, tall forest had been replaced by tussock grasslands, scrub, fern and patchy, low forest. The Mackenzie could not withstand fire.
The next phase of settlement involved European graziers. Sheep and cyclical rabbit outbreaks reducing native species.
From the 1970s to the 1990s, wool and sheep meat export values increased, giving income that could be spent on weed and pest control. More recently incomes for sheep have decreased and weeds and pests have increased - wilding pines, Alexandra roses, wallabies, possums ... and the rabbits are back with a vengeance.
The Department of Conservation (DoC) has funding to control pests but can manage only about 10 per cent of the area required.
The extra $20 million a year over the next four years in the Budget will enable pests over only another 1.8 million ha (7 per cent of New Zealand's area) to be controlled.
The $2.4m over 4 years for the protection of unique biodiversity and landscapes in the Mackenzie Basin announced in the Budget is insufficient to stop the weeds and pests.
Farmers do what they can to help. In addition to what DoC spends on Haldon Station in the Mackenzie Basin, the manager allocates upwards of $100,000 a year on weed and pest control on its 22,000ha.
The station has 600ha of irrigated flats, not visible from the road, and the forage grown allows animals to be fattened and contracts to be met. The spread of hieracium weed has been halted, and the area provides a habitat for birds.
There are pros and cons associated with irrigation.
A report on the Mackenzie available on the Ministry for the Environment's website states that "from a positive perspective, irrigation would reduce the erosion risk within the basin and also increase the opportunities for enhancing biodiversity values. From a negative perspective, irrigation increases the risk of contamination of ground and surface waters and could adversely impact upon landscape values".
The Auditor General's recent report agrees that irrigation is linked to issues such as water pollution, but also states that properly timed irrigation can reduce nutrient and effluent leaching into waterways.
And our waterways are a classic example of 'rose coloured spectacles'.
NIWA scientists have stated that "40-50 years ago a lot of rivers had serious pollution from very poorly treated point source sewage and industrial discharges. These are now largely cleared up".
Knowledge and science have made the difference – technological advances enable change.
For the Mackenzie Basin there are choices.
Pay more for the meat and wool to allow improved expenditure on weed and pest control; pay more taxes to allow DoC to do the job; pay more taxes to allow the government to subsidise farmers to stay on the land; let the farmers walk off the land and weeds and pests to take over ... or let innovative farmers manage the environment using new technologies.
The answer to the future is more research, and science-based decisions aligned to New Zealand's goals. Nostalgia is a trap ...
