- Conservation-preservation of the natural environment.
- Ecology-the study of the relationships between living things and their environment.
- Sustainable development- he management of resources in such a way that the ability of the system to replace itself is greater than the level of exploitation.
- In urban areas they contain a wide variety of habitats such as industrial sites, derelict land and parks, thus difficult to make generalisations about urban ecology- all these habitats contain different mixes of flora and fauna.
- This means there are opportunities for secondary succession, particularly where land becomes derelict.
Urban Niches
- Many urban habitats are specialised, within one site a number of different niches or microhabitats might be available for plants and animals to colonise. e.g. bare tarmac, stone walls, Mosses taking root on high buildings.
Colonisation of Wasteland
- Plant succession-the change on a community of species over time, is brought about by changes in the microenvironment due to such as the supply of new species, competition between species and changes in habitat.
- The types of plants that can initially colonise are influenced by:
i). Slope – horizontal surfaces debris accumulates, eventually develops into soil.
ii). Moisture availability-gentle slopes, rainwater accumulates and steep slopes-faster runoffs.
iii). Aspect – south facing slopes are warmer and drier.
iv). Porosity – (ability to hold water), the greater porosity the quicker the colonisation.
v). Surface roughness – allowing plants to get a hold.
vi). Pollution levels – substances that are toxic to plants such as the lead contaminates on the ground.
Succession – Industrial site
Stage One: Pioneers –
- Mosses and lichens are the first plants to develop on bare surfaces.
- Able to exist in areas with little water, obtaining nutrients through photosynthesis.
- When the plants die they provide a thin mat of organic matter, produces a protosoil that other species can root into.
Stage Two: Oxford ragwort –
- Cracks in the surface provide sheltered places for seeds to germinate and retain moisture.
- Oxford ragwort, wind-blown seeds, has a long flowering season 180-190 days, enables it to produce millions of seeds.
- At this stage, succession is usually rapid.
Stage Three: Tall herbs –
- As these plants die they produce a thicker and more nutrient-rich soil.
- Taller plants that are more demanding of good growth conditions can become established such as Willowherb.
Stage Four: Grassland –
- As soil enrichment continues, the amount of grass in the vegetation increases.
- Japanese knotweed grows up to 3m in height, their dense canopies shade out most species beneath them.
Stage Five: Scrub Woodland –
- Processes of soil enrichment and competition continues, taller herbaceous plants replaced by shrubs and eventually trees.
- As herbaceous plants thicken it becomes difficult for these small-seeded plants to establish.
- As plant succession develops, there are changes to the fauna:
- Soil fauna increase the number of earthworms as soil improves and increase in the number and diversity of the insect population.
- Sub-stratum variations-caused by differences the surface being colonised.
Ecologies Along Route Ways
- Routeways are distinctive habitats because exotic species of plants and insects may be brought in by traffic, provide wildlife corridors such as foxes.
- Railway lines during days of steam trains there were frequent fires which burnt tall species allowing light through encouraging light-demanding species to establish
- Windborne seeds can be sucked along by trains and a lack of human interference encourages wildlife including badgers.
- The nitrogen-rich exhaust fumes boost the growth of some wild flowers and increase the presence of insects and animals further up the food chain.
- Canals act like long ponds providing a habitat for a variety of aquatic plants such as ducks.
Introduction of New Species
- Cities are centres for the establishment and spread of foreign species, species:
- Europe such as Sycamore.
- Japan including Japanese Knotweed.
- Such species can be introduced by windblown seeds, seeds carriers by animals and forms of transport such as trains.
- Urban areas are attractive because of the variety of habitats, the constant creation of new habitats and the reduced level of competition.
Gardens and Parks
- Are areas where the vegetation is managed:
- Species are introduced from overseas and others are removed or controlled by mowing, weeding or the use of pesticides/herbicides.
- Sports fields reduce the diversity of plant species by maintaining grass pitches.
- Altruistic motives to give a dull urban area some colour and improving the aesthetic value of the area.
- Improving the visual outlook-hiding eyesores such as factories encourage businesses or residents to move in.
- Schools produce a diverse environment for study purposes.
- Local businesses may want a pleasant site to attract customers.
- Local authorities provide the public with an arboretum.
- Birdwatchers wish for a diverse environment to attract new species.
- Act as noise and pollution inhibitors.
- Provide shade in hot urban environments.
- Reduce soil erosion on embankments.
Changes in the Rural Urban Fringe
- Although much of the land on the rural/urban fringe is a green belt area meaning that it’s protected from development, there will be increasing pressure to do so as plans for 50,000 houses over the next few years.
- The rural urban fringe is under pressure from development, In the UK are designated green belt, with regulations that strictly control new development.
- Farmers face problems from illegal encampments, trespassing and vandalism.
- Secondary succession may begin on unintended fields with the growth of weeds.
- Despite a lack of investment, land prices are often high, due to speculation of future development, derelict land has an advantage in gaining planning permission.
- Recent government policy is in favour of sustainable development of the rural-urban fringe and the recycling of derelict/degraded land including planting of woodland
- Country parks are relatively unmanaged and harbour more natural plant communities, providing potential breeding sites for bird species such as skylark.
Ecological Conservation Areas
- Conservation areas are developed for:
- Encouraging wildlife back into cities.
- Making cheap use of an otherwise derelict area.
- Reducing maintenance costs in an area.
- Maintaining a diverse species base and reintroducing locally extinct species.
- Such work includes:
- Planting of trees, planting of native species, dredging of ponds and soil improvements.
- Group organisations behind such conservation include: The National Trust.
- Different groups have different priorities, local authorities have planning needs and must balance the desire to make use of derelict land against the potential cost to local taxpayers
- For example, conservation groups want to create environments where traditional species can establish, and local people want a safe environment for leisure.
Dulwich Upper Wood Conservation Area
- This was once a wooded area and the site of Crystal Palace however now it has been turned in to an ecological conservation area which is open and attempt to accommodate everyone.
- Is open at all times.
- Has a network of trails, some are suitable for wheelchairs?
Species in the Wood
- Trees like oak and ash, ground in the wood is deeply shaded, only a few shrubs. Laurel and a few plants from the ancient woodland such as bluebell.
- Over 250 types of fungi including mushrooms, they live on dead wood or leaf litter helping to break down these materials and return nutrients to the soil.
- Many mammals such as foxes and over 40 species of birds including woodpeckers.
Why the Site is Interesting?
- Conservation of both abandoned Victorian gardens and ancient woodland.
- Several preserved and re-created habitats e.g. wet areas and herb gardens.
- The site is both managed and allowed to grow wild in some areas, a range of different habitats.
- Plenty of wildlife, over 40 species of birds.
- Original habitats preserved, enabling native species of plants and animals to survive.
- A good example of how habitats can be preserved and created and still allow public access through a network of trails.
- The site has an educational value with a posted nature trail.