Looking down on a community from a high vantage point it immediately obvious that its dominant ecosystem is associated with trees and shrubs in the cut grass of parks, gardens, roadside verges, and derelict land. These places are a vital part of the community's space for leisure and recreation, and in urban environments they provide the only easily accessible places for schools to do ecological work.

Image1.jpgThe starting point can be a patch of mowed lawn. One tree (Fig 1) can make a lawn into a complex ecosystem. All appraisals begin by asking questions about why a particular patch is maintained, who cares for it, and why. They may be applied individually, to highlight particular features, or together, for working on an ecosystem. The common aim is to devise a local plan to increase biodiversity in relation to who uses the area and for what purpose.

Applied to a school lawn, a park, or a back-garden, the appraisals will, year on year, build up a wildlife inventory, which can be compared with that of schools in other places to form a national picture. The results and conclusions will also be a valuable input to neighbourhood management plans for environmental improvements. Together they provide a curriculum basis for long-term studies on 'ecosystems recycling', and 'care for the environment', for science at Key Stages 1-4.

Amenity grassland is of limited educational value when approached as a collection of species, without considering its management. Grass-SCAN approaches mowed grassland from the opposite direction; as a universally accessible model of ecological management. From this viewpoint, the first task is to determine the management objectives for the patch. The objectives may vary considerably e.g. from maintaining a uniform velvety ornamental grass monoculture to maximising the lawn's species diversity, of say earthworms, or dicots. The next step is to set up a monitoring programme based on indicators by which the success of the management plan may be judged. These indicators, such as 'sward height', a list of the weed species, or the number of daisy flowers, will depend on the management objectives. From another angle, a management plan could be written to run an experiment where a mowed lawn is used to demonstrate an important ecological principle, such as competition between grasses and clover. In all cases the aim is to do year on year measurements to establish trends and variations of mowed grassland as a managed ecosystem.

(i) Grass-SCAN takes grassland as a general scientific example of deflected climax vegetation managed by biotic interference in the form of grazing, seasonal mowing, burning or weed spraying. It focuses the application of biological principles of grassland management on the selection of species and strains of grassland plants for maximum productivity in particular situations, such as:-

· the work of farmers who manage grazed grasslands of chalk downs, mountain
· pastures, and common lands, to maximise animal production;
· the work of countryside managers operating management plans to maximise
· wildlife diversity of grazed habitats, adding or subtracting livestock, if over-, or
· under-, grazing upsets their target species diversity.
· the work of groundsmen who maintain public amenity lawns, bowling greens and
· sports fields.
· the work of home gardeners who consume resources to maintain a garden lawn
· as a sustainable leisure activity; the question of 'To mow or not to mow? has a
· direct bearing on domestic activities as sustainable operations.

(ii) Using a grassy open space as an outdoor classroom/laboratory offers windows into all these professions which depend on the application of scientific research to grassland in the context of making conservation management plans. Above all, Grass-SCAN gets people involved in 'systems hinking' that is necessary for managing any set of processes, be it a lawn or a business.

(iii) In summary, a Grass-SCAN management plan is expressed as a database to record information about the day-to-day, and year-to-year, jobs, and the monitoring, required to maintain a school lawn as an important expression of local biodiversity. As such, it models the work of a countryside manager operating a management plan for an ecosystem such as a woodland, or heather moor.

Grass SCAN offers scope for using a grassy patch to carry out ecological investigations from the following three viewpoints:-

- management;
- the study of biodiversity by making an inventory of the weeds;
- the study of life cycles of individual weed species.

This information is to support the study of life cycles.

Study of the general life cycle is basic to all aspects of the science curriculum and it is surprising how little is known about certain stages in the lives of quite common plants and animals. With any organism such a study involves asking and answering a lot of questions that can be conveniently grouped as follows:

(i) Germination
The main questions are: What are the essential conditions for germination ? Do the seeds need to be exposed previously to periods of cold, light or darkness ? When do seeds germinate, autumn or spring ? What proportion of seeds is viable at this time ? For how long do seeds remain viable ? (Evidence may come from unexpected plants growing on sites of demolished buildings. Is germination epigeal or hypogeal ?

(ii) The seedling
What does the seedling look like - are the first leaves different from later leaves ? Early stages of many common plants are imperfectly known, and few descriptions are available. Most seedlings are found in much greater numbers than the mature plants. This implies a high casualty rate - what are the factors causing this? Points to be investigated include both inter-and intra-specific competition with other plants, and the feeding, trampling or fouling activities of animals (induding man).

(iii) The mature plant
In what conditions does it flourish most ? Points to consider must include shading and a whole range of soil factors including pH, soil depth, organic content and mineral content (particularly lime status and salinity). Geographical distribution is important; very often factors which are regarded as limiting, are so only because the plant is near the boundary of its geographical range. Many plants which are regarded as calcifuge or calcicolous in this country display no such tendency in the middle of their range in Southern France or Germany; being at the fringe tends to accentuate the effects of any slightly unfavourable factor.

How efficiently can the plant regenerate after cutting or trampling and what form does this regeneration take ? After cutting or grazing, the meristematic regions at the bases of grass leaves are left more or less intact; in broad-leaved plants they are destroyed so that regeneration must come from axillary buds.

Habitat factors are often a cause of 'phenotypic variation ' in shape, size and colour of the plant; how does your plant vary in response to shading or changed water status due to flooding or drainage ? Many of the variations in size, shape and coloration turn out on investigation to be the result of internal disturbances caused by parasitic animals or fungi. The investigation of host-parasite relationships is of great practical importance in the control of disease and pests where the plants are economically important.

(iv) Flowering
What determines the time of flowering ? Day length and shading are obviously both important factors - are there any others, and if so, how do they affect the numbers of flowers and hence reproductive capacity? How is the flower pollinated and to what degree is it specialized in this respect ? If it is insect-pollinated are the insects also specialised ? What size are the pollen grains; are they sculptured, and if so what is the pattern like ? What is the nature of the stigma and how does the pollen reach it ?

(v) Fruiting and seeding
Flowers give rise to fruits and seeds whose forms are dearly related to their modes of dispersal, and where these are inefficient, survival of the species may depend on a high level of fecundity. Thus for any plant we might ask: What are the fruits and seeds like, and how are they dispersed ? How effective is this dispersal - what proportion of seeds reach a situation where there is some chance of germination and survival ?

In studying the plant, vague generalizations are of limited value, so wherever possible one should make quantitative records of dimensions or numbers, and record the kinds of variation seen within or between populations.