Ecological Knowledge and Environmental Problem-Solving Concepts and Case Studies (1986) / Chapter Skim
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18. Restoring Derelict Lands in Great Britain
18. Restoring Derelict Lands in Great Britain
Pages 248-274
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From page 248... ...
More recently, society has demanded the creation or restoration of more complex natural communities of plants and animals, even though this goal is more difficult and expensive. The task requires knowledge of the tolerances of plants for the environmental conditions; of the ways in which plants compete with one another for access to water, light, and mineral resources; and of the course of succession of plant species after establishment of pioneering vegetation.
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From page 249... ...
In some instances, derelict land detracts markedly from an otherwise pleasing landscape and must be reclaimed in the interests of visual amenity, irrespective of a readily apparent productive after-use. The major concern
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From page 250... ...
As a result of mining activities, seminatural vegetation is being destroyed over much of the site. The general objective of the experimental work described here was to learn whether it would be possible to recreate the seminatural grasslands being destroyed by mining operations.
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From page 251... ...
This search for universal recipes that eliminate, rather than accommodate, constraints on vegetation development has colored much of the research on derelict land reclamation. The major constraints on plant growth on derelict land, apart from possible toxic effects, are low nutrient status, low soil organic content, drought stress, and, if the material has been mechanically sorted, uniform particle size.
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From page 252... ...
The traditional approach to reclamation of derelict land for visual amenity has been based on agricultural techniques. In the period 1967-1972, the mining company made considerable efforts to revegetate areas on Longstone Edge where extraction was complete or where there was a temporary halt in operations.
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From page 253... ...
These low-productivity grasslands could be expected to develop into diverse swards akin to the existing seminatural vegetation. Local populations of plants could not be used as the sole source of propagules in this research, because of the difficulty of interpreting the experimental results.
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From page 254... ...
The decision to introduce native species deliberately raised an important issue, which has since achieved greater prominence. Deliberate introductions are discouraged by scientists, mainly because they disrupt natural distribution patterns, particularly of local ecotypes.
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From page 255... ...
For the first 5 years, the plots were monitored fairly intensively, but they have since been assessed only infrequently. One area of Longstone Edge provided an opportunity to investigate the effect of a grass seed mixture on the rate of invasion by native species under natural conditions.
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From page 256... ...
The major finding of this study was that soil nutrient status was the most important factor in controlling succession in urban grasslands (Wathern, 1976, 19801. USES OF KNOWLEDGE Of the ecosystem modifications listed by Wathern (1984)
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From page 257... ...
The revegetation of mineral workings on Longstone Edge was designed to satisfy five criteria: reinstated swards should be inexpensive to produce, result from a single simple treatment, require no intensive management, be visually pleasing, and resemble surrounding seminatural vegetation. The research involved field observations and theoretical considerations aimed at understanding the relationships between reinstated grasslands and the environment and then application of this information in devising a reclamation scheme.
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From page 258... ...
Composition of a particular community, however, is dictated not only by the growth rates of the constituent species and by the physical and chemical characteristics that can limit the full realization of this potential. The degree of disturbance of the environment, such as grazing, is a third factor.
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From page 259... ...
In contrast, several tall herb species included for comparative purposes showed initial high rates of seedling establishment, but then failed to survive. Thus, Grime's concepts of community ecology are directly relevant to derelict land reclamation.
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From page 260... ...
Analysis of a chronosequence of sown urban grasslands provided some insight into the fate of vegetation created for visual amenity. In Sheffield, extensive areas of grassland have been produced for public open space around municipal housing in recent years.
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From page 261... ...
SOURCES OF ECOLOGICAL INFORMATION The overall objective of the Longstone Edge trials was to create seminatural vegetation resembling the surrounding diverse grasslands on the nutrient-deficient subsoils of the reinstated mineral workings. The research had two basic assumptions: sward production depends on the relation of soil nutrient status to the growth rate of constituent species, and diversity depends on sward productivity.
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From page 262... ...
The results showed that the younger grasslands on soils with high nutrient status were dominated by Lolium perenne swards, whereas older nutrient-poor soils carried grasslands dominated by fine-leaved Fes tuca species. Although the older urban grasslands were more interesting, there was no evidence from an initial analysis of the data that they were more diverse than younger grasslands.
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From page 263... ...
The major conclusion from these experiments is that grassland composition can be manipulated by changing nutrient status with fertilizer applications. The park grass experiment described by Brenchley and Warington (1958)
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From page 264... ...
The results demonstrate that diverse vegetation can be created artificially under conditions of moderate stress, as the theory predicts, and that the techniques used constitute a worthy strategy for reinstatement of disturbed land for visual amenity. Analog Studies No reports of previous attempts to reinstate mineral workings to seminatural vegetation were discovered during a systematic search.
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From page 265... ...
Experimental work in the Netherlands on landscape reinstatement was of particular interest, but it was not seen until the Longstone Edge trials had been established. The Dutch experience was useful in interpretation of the experimental results, because a similar approach had been adopted independently in many instances.
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From page 266... ...
The approach seeks merely to redress somewhat the losses of seminatural vegetation that are occurring. The alternative is that yet more highly productive grazing land will be created in reinstatement, irrespective of location.
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From page 267... ...
Although increased scale should not affect the outcome of reinstatement, it would establish whether the approach is usable on an industrial scale. The possibility of developing a "wildflower" mixture for reinstatement schemes based on commercial sources of native species has been considered and rejected.
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From page 268... ...
The study has provided experimental support for theories of community ecology, and theoretical considerations, particularly of plant strategy and community ecology, help to weld the experimental work into a coherent whole. This unity converts what might have been regarded merely as an interesting set of empirical observations on a set of reinstatement trials on a small site in Derbyshire into a radical alternative strategy for the revegetation of derelict and despoiled land.
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From page 269... ...
1978. The restoration of vegetation on derelict land produced by industrial activity.
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From page 270... ...
1970. Relative Growth Rate: Its Range and Adaptive Significance in a Local Flora.
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From page 271... ...
1981. Creating Attractive Grasslands Using Native Plant Species.
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From page 272... ...
It showed the importance of drawing on a variety of sources such as ecological facts, ecological theories, analog studies, and the reasoned judgment of persons familiar with the local areas if sound solutions are to be achieved. The Longstone Edge project took its direction from the recognition that most derelict land in Britain occurs on nutrient-poor soils and that attempts to make such areas fertile in the long run require repeated fertilization, which, because of its cost, is seldom feasible.
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From page 273... ...
Because derelict lands are likely to be diverse in their nutrient status, even if they are mostly on poor soils, better understanding of the importance of particular combinations of soil nutrients for the success of competing plant species should enable both better selection of species for colonization and the cultivation of specific genotypes for use in particular circumstances. Restoration ecology might also contribute substantially to our knowledge and understanding of seed banks in the soils and their roles in the development of vegetation after disturbance.
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From page 274... ...
274 SELECTED CASE STUDIES specific knowledge of local conditions, continued developments in the theory of competition, plant succession, seed ecology, and plant nutrition are likely to remain vital to restoration ecology far into the future. References Bradshaw, A
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