Colonisation of wasteland Flashcards
What is plant succession brought about by?
Microoenvironment changes.
Occur due to new species supply, species competition habitat changes.
Number of different successions occur within a habitat.
What factors influence the types of plants that can colonise on a particular site? 6
- Slope - horizontal/gentle slopes - debris accumulates to make soil.
- Moisture availability - gentle slopes - rainwater accumulates/drains away slowly, steep slopes, faster runoff creates dry areas.
- Aspect - south-facing slopes are warmer/drier.
- Porosity (the ability to hold water) - surfaces that can hold water are colonised more quickly.
- Surface roughness - allowing plants to get a hold e.g. glass is too smooth for most plants.
- Pollution levels - toxic substances may contaminate ground.
What is the FIRST plant succession stage for an abandoned industrial sit? 1/5
THE PIONEERS.
Mosses/lichens on bare surfaces.
Exists with little water - nutrients from photosynthesis.
Concrete - slowly weathered by the production of acids.
Plants die - thin mat of organic matter.
Mixed materials- protosoil.
Other plant species can root into this.
What is the SECOND plant succession stage for an abandoned industrial sit? 2/5
OXFORD RAGWORT.
Cracks - shelter for seeds to germinate/retain moisture/dust - helps root plants.
Windblown seeds - Oxford Ragwort (180 days - long flowering season) - millions of seeds produced.
Dandelions and perennial rye-grass.
Ruderal species - able to tolerate waste ground/rubbish.
Rapid stage.
What is the THIRD plant succession stage for an abandoned industrial sit? 3/5
TALLS HERBS.
Higher plants die - thicker/more nutrient-rich soil.
Taller plants established e.g. rosebay willowherb.
Spread by seeds and then rhizomes - extend up to 1m per year.
Michaelmas daisy and Jacob’s ladder.
Gradually shade out smaller plants - stops them from photosynthesising.
What is the FOURTH plant succession stage for an abandoned industrial sit? 4/5
GRASSLAND.
Soil enrichment continues - grass increases.
Smaller meadow grasses - replaced by taller species.
Appearance - scattered clumps of tall herbs.
E.g. Japanese knotweed - 3m in height - dense canopies can shade out most of the species beneath them.
What is the FIFTH AND FINAL plant succession stage for an abandoned industrial sit? 5/5
SCRUB WOODLAND.
Continued soil enrichment/competition.
Taller herbaceous plants are replaced by shrubs, and eventually trees.
Woody plant colonists e.g. birch possess light, wind-bourne seeds - but thick herbaceous vegetation makes it difficult for establishment - unless in a case of a fire.
Larger seeded trees e.g. sycamore are established.
Dense thickets of bramble develop.
Able to complete as roots can grow into deeper crevices in the rock/concrete.
What changes to the fauna are made as the plant succession develops?
Soil fauna e.g. earthworms numbers increase.
Increase in insect number/diversity.
These provide food for small mammals - allows predators such as kestrels/urban foxes.
Tree arrivals - squirrels.
What are sub-stratum variations?
Caused by differences in the nature of the surface.
Can lead to several parallel successions developing.
Surfaces can be acid/alkaline.
Can include wetland, concrete, tarmac and rubble.
SHEFFIELD EXAMPLE OF SUB-STRATUM VARIATIONS. 3
Different successions on different types of rubble.
Three sub-strata present:
1. Crushed brick and mortar rubble.
2. Several metres of whole and half-bricks on a slight slope.
3. A granular layer of ash and slag.
How do railway lines serve as habitats?
Animals able to move around cities.
Steam days - frequent fires on the lines burn off tall species and allowed light through - encouraging light-demanding species to establish e.g. primroses.
Windbourne seeds e.g. Oxford ragwort.
Brought over by the Duchess Beaufort - now spread across the UK with the railway system.
Tracks fenced off - lack of human interference,
Wildlife e.g. badgers and urban foxes, encouraged.
Bramble-filled areas - nesting site for birds.
Network Rail - removed large areas of woodland alongside rail tracks.
How do roads serve as habitats?
Nitrogen-rich exhaust fumes boost wild flower growth.
Increases insects/animals.
Flowers reduced by mowing.
Some roadsides are managed e.g. London streets - London plane tree is planted e.g.sycamore.
Soil removed on routeway on the sides - verges make good soil beds.
Grass seed mix/flower meadow seed - good variety.
Urban niches developed.
Flowers - Britain in Bloom competition.
How do canals serve as habitats?
Act like long ponds.
Provides for a variety of aquatic plants e.g. yellow flag iris.
Waterfowl e.g. moorhens and ducks.
Water-loving insects e.g. dragonflies.
What is the urban blight, and what is it affected by? 5
Agricultural land near cities begin to deteriorate
- Vandalism e.g. fly tipping.
- Tourism pressure.
- Leisure pressure e.g. dog walking.
- Traffic pollution.
- Developers used the farmland..
What are garden creations, and what are the features of them? 4
Range of different rural/urban fringe gardens.
- Paved areas.
- Well kept lawns - chemicals used.
- Exotic wildlife plants.
- Wildlife gardens.
