Greenstructure and Urban Planning

Sustainable Urban Environmental Planning - Community Plans

by Anne Beer

The natural environment : biotic data collection

For this part of the information gathering work you need to collect the data on the plants and wildlife living in your study area and expand this with a consideration of the other species which could naturally have been expected to grow and live in the area in the recent past.

Do not worry if you are not familiar with the names of plants; you will find that you can still do some useful preliminary survey work. You will, however, need an ecologist or botanist to help with the assessment stage and later with deciding what to grow and where to grow it.

a. Plants

Position and extent of vegetated areas

On a scale plan:

plot the position of the main groups of vegetation including woodlands, scrub and major hedgerows

note their maturity through site visits

plot the position of any mature, large trees of importance as landmarks and any trees covered by tree preservation orders.

Air photographs are the best for this work.

For woodlands you should note:

Edge Type. An edge with a high degree of diversity can be of great importance to the ecology of an area, as it increases the opportunity for diversity of habitats.

The condition of the vegetation. This is particularly important as it enables better decisions to be taken as to which vegetation must be kept as it is and which could reasonably be felled. Normally it is only important to ascertain whether the individual tree is in good or bad condition when detailed site design is underway. When trying to get a general idea of the condition of the vegetation, look for dead branches at the extremities of the trees, look for trunks that appear to have been damaged so that the tree's food supply has been interrupted and look for signs of fungoid growths (lumps which do not normally appear on healthy trees). All these will be signs that the trees are dying back. In particular, if you find more than a small number of trees in one area looking unhealthy, it is essential that you find an expert to look at them.

Record the tree and shrub species

This could be left to a later stage in the planning process, but since there is a strong link between species and biodiversity, it is something that needs to be done eventually and preferably by plant experts.

You need to be able to establish the most common species of trees, shrubs and herbs in the different areas of woodland - from this data and the data on soils and climate an ecologist can begin to predict the range of wildlife that can be anticipated in each part of the area. for biodiversity assessment purposes it is the native species which are the most valuable.

If you cannot recognise at least the native species yourself, get help - someone in the local community could well be an expert in plant identification. It is important for the future development of ideas on enhancing biodiversity that you identify the species which thrive locally and how any variations in species relate to localised environmental conditions. Reflecting such variations as you develop proposals for the future use of plant material in the area will help you to produce a plan which builds on the special character of the site. Soil, ground water and microclimatic conditions can all influence vegetation, so note any factors that seem to have an impact on the distribution of species across the project site.

Look carefully at the hedges and try to establish approximately how old these are, as this will help you to decide whether they are a special feature worth keeping or not. (In the UK it has been established that the age of a hedge can be estimated very roughly by counting the number of woody species occurring in 30 metre lengths. Here, for each different species you find in a hedgerow you can estimate about one century.

The older hedges are those which tend to be of more ecological interest, carrying a wider range of wildlife. If you do find a hedge with a great diversity of species, it might be a forest remnant and in that case will be worth preserving as a wildlife habitat, if not for historic purposes. The community ought to talk to an ecologist about its hedges if you find any with a high number of species.

Plotting other vegetation

Gathering information about grass, ruderal (weedy) vegetation and wetland areas is important for environmental planning within an urban area as well as in rural areas:

plot all areas of regularly mown short grass, anything that looks like a lawn or playing field

plot 'rough grassland', that is all the areas of grass that appear rarely, if ever, cut. Note, if you can, the relative level of species diversity as that will help to identify which areas need 'improvement'.

show separately all the areas of grassland which are dominated by tall herbs. These flowering plants are good for attracting all kinds of insects.

plot all areas of bramble, ivy and low scrub. These too are areas which support a wider range of wildlife than grass can by itself and are, therefore, important to wildlife.

plot all the areas of marshy land and all the water margins in which plants grow and again note the level of diversity

identify areas of ruderal (weedy type) vegetation which comes in when ground is intermittently disturbed. It will tend to be rather open in character, contain annual plants and in towns probably also garden escapes, that is flowering plants and shrubs which are most normally grown in gardens.

You need this level of information so that you can decide whether there are any areas which could be encouraged to go 'wild' to add to local biodiversity, which at the same time reduces maintenance costs .

Landscape management regimes

Write brief notes about how each area of landscape appears to be managed; note too how frequently the management occurs. For instance, in Britain you would note whether the hedges were untended, whether they were obviously cut by a tractor-powered cutter, or have been treated in the traditional way and carefully laid by hand, as each of these has an impact both on biodiversity and appearance.

Find out how the vegetation on the project site has been and is being managed. Assess whether the management will continue; if not then what arrangements are being made and how is this likely to change the local landscape?

Almost all landscape in a country such as Britain is managed in some way, even if that management is infrequent. The management of most countryside landscapes is done by farmers as part of the daily running of their farms, by woodland owners as part of their requirement to make profit out of timber and by public agencies looking after the relatively small parts of the landscape which are used for recreational or military purposes. Even remote upland hills can turn out to be managed, being grazed by sheep, or having the heather burnt off at regular intervals. In towns we need to know in detail how each part of our landscape is managed and by whom, so that we can:

• predict how the urban landscapes will alter as the land management practices change, and

• examine the link between the method of land and landscape management and the level of biodiversity in an urban area.

b. Wildlife - mammals, birds and insects

The presence of wildlife in any area is linked inextricably with the plant species that live on the area of land, although many other environmental factors will determine which wildlife actually inhabit the area. These factors include the environmental change caused by man's activities. It is possible to predict that if you find particular a plant association in certain environmental conditions, certain wildlife could be encouraged.

If you spot any wildlife on your walks around the site, or you have been told that wildlife inhabits the site, try to identify it. Note whether any site appears to be relatively rich in any particular species. Even when a site is urban wasteland it can still be supporting important wildlife. For instance, in Britain one of the best known links is between butterflies and the buddleia shrubs which so often thrive on urban wasteland. Thistles, nettles and brambles are also particularly good for attracting wildlife in urban areas, along with shrubby willows. Find out about the local links between plants and wildlife from local ecologists.

Many wildlife species do not like disturbance and will abandon a site when it or adjacent land is developed. Some wildlife is not appropriate to have in or near sites occupied by people because of the safety aspects. The presence of such wildlife implies that a decision has to be taken not to develop the site, or alternatively to accept the loss of yet more wildlife.

Outside the milder parts of western Europe and a few other areas, insects can be a major problem in deterring people from living near certain trees and shrubs, and for plant associations. It is important to work out how a community can deal with these issues.

c. Biodiversity assessment

Assessments of biodiversity are best carried out by expert field ecologists, but it is not always possible to find or pay for such help in a community level study. The following is a simple method devised for use in urban and suburban areas. It enables non-experts to make a very rough preliminary assessment of the present level of biodiversity on an area of urban land and the potential of that land to support an enhanced level of biodiversity.

Using such a method does not suggest that one vegetation type is more valuable than another, for instance that woodland is more valuable than grassland. It only allows you to spot which areas, within a vegetation type, are most likely to be worth trying not to disturb during changes in land use and land management. There is, however, no substitute for expert advice. Should anything be found that appears to be of value or in any way unusual, employ an ecologist.

Using the information that you gathered in the vegetation survey, you should now plot the different vegetation types and classify their value as wildlife habitats using a system like the one outlined below, but bear in mind that it is very simplistic and will need modification for local use.

Woodland

Using a plan which indicates any different types of woodland - deciduous, coniferous, mixed woodland and young woodland or scrub, consider each wooded area in turn and decide into which category of biodiversity value it falls:

High value

Areas of woodland with a mixture of different native tree and/or shrub species. To be in this highest value category the plants in a wood should also be of different ages and in most cases there should be a dense understorey (lots of herbs and low-growing shrubs on the woodland floor). If you can recognise the main species in this mix, list them. Include in this category any areas of woodland edge and glade edge which have a dense understorey.

Valuable

Woodlands with native trees but with no dense understorey.

Lower value

These would be woodlands where all the trees seem to be of the same species. State which species and whether they are native plants.

Grassland and ruderal (weedy) areas

Indicate on the plan any different types and then classify them as follows:

High value

These are the areas of grass and herbs with a high level of diversity. They include the areas where individual trees grow in the grass. These are the areas you identified in your vegetation survey as being rarely, if ever cut and being composed of many different species. Areas where a few shrubs are established may be included, but not the areas where the shrubs are beginning to develop to the extent that they suppress large numbers of herbs.

Valuable

These include the areas where you found that the herb layer was composed of diverse species and cut once or twice a year. Also included are the areas where native shrubs and pioneer trees are invading the grassland in substantial numbers.

Lower value

The areas of grass which are infrequently cut but where you found little variety in the species. Also the areas where non-native shrubs and trees are invading the grass.

Very little value

This includes close mown, relatively recently sown grass, such as found in lawns and playing fields.

Hedges

Indicate on the plan and then classify them as follows:

High value

All hedges with more than five different woody species in a 30 metre length, no matter how they are managed at present.

Valuable

All hedges with between three and five different woody species in a 30 metre length which are managed by layering, hand cutting, or are overgrown.

Lower value

All hedges with only one or two species which are layered, hand cut, or overgrown. Also all hedges which are machine cut but still allow for a mass of herbs to grow at the base.

Very little value

This includes the single species hedges kept cut right down by machine and where the herbs are regularly removed from underneath.

Wetlands and water margins

These can be very important to the local ecology, mainly because so many of them have disappeared as man has drained the land for development or to improve agricultural or forestry productivity. So if you do have any areas of wetland on your site, you can almost automatically designate them as worthy of preservation and conservation (even if they look a boggy mess to you!)

Indicate all wetland and water areas on your ecology map as a valuable or potentially valuable resource.

You now have a very crude guide to the relative ecological value of the different parts of your site and due to the strong link between wildlife and vegetation, this also gives you some idea about the potential level of biodiversity sufficient anyway in a local community area to identify areas deficient in vegetation and wildlife. However, you must remember the limitations of this crude system and in particular that this method will not identify the very special and rare habitats and groups of plants which take an expert botanist to identify. Such areas may well already have been identified by local authority ecologists and included in nature conservation lists - it is very important that you record these as areas not to be the subject of land use or land management change. What happens on the land around such special sites is also very important to the survival of plants and associated wildlife and needs to be considered.

Sustainable Communities - local action

Introduction

Background

Abiotic data

Biotic data

Social, cultural and economic

A Community Environmental Plan

Local policies

Neighbourhood "actions"

Landscape Structure Zones

References

Maps - Case Study

Return to top of page

click here to RETURN TO COST C11 WEBSITE