Colonisation of wasteland
The colonisation of wasteland occurs through natural succession on for example an abandoned industrial site where urban decay may have taken place or de-industrialisation. The first species to colonise are pioneer species which are tolerant of low moisture availability and lack of nutrients. These include lichens and mosses which live in cracks where moisture is more available and live of nutrients from the bare surface and through photosynthesis. This colonisation usually takes 1-3 years. The next stage which occurs over 3-6 years is the introduction of oxford ragwort by seeds carried on the wind or invasion form a close-by site. The level of nutrients has increased allowing more such species to colonise however vegetation still grows in crack to offer protection and moisture.
The next stage between 8-10 years pioneer species starts to become shaded out by taller species of grasses. This creates a nutrient layer of humus allowing more complex plants to colonise such as rose bay willow herb. As competition increases plants colonise through windblown seeds and rhizomes under the soil which can grow up to 1m per year. As nutrients increase worms are introduced and taller species replace smaller ones. Grasses weeds and bracken start to appear including Japanese knot weed. If left for enough time Birch, willow and alder trees may become established which are able to survive on poor soil conditions, as well as rowan hawthorn and sycamore.Planned/ Unplanned introduction of new species
The planned introduction of species
Unplanned introduction of species has come from seed dispersal by the wind as well as animal’s birds and transport. Oxford ragwort a member of the senicio genus was introduced to teh Duchess of Beufords garden in the 1700’s. The yellow flowing herbaceous plant was then introduced to the Oxford botanic garden where it escaped and spread on to the railway lines in the 1800’s. It then began to spread rapidly as a result of the passing trains when it got caught or was blown into carriages that passed. As a result it has spread all over England, Wales and parts of Scotland. Its native home is the volcanic mountains if Sicily which are somewhat resembled by the limestone on which it is commonly found in England. There are benefits and negatives to introducing new species to a habitat. The positive effects are that some may benefit local wildlife becoming an alternate source of food allowing particular species to flourish as a result; they may also not be competitive with native species such as corn and tomato. However, invasive species such as Japanese knotweed form Japan has become Britain’s most invasive species and its presence is growing, causing problems especially in conservation areas such as Troopers hill were habitats are very sensitive. The introduction of species can also be detrimental to local wildlife, as has been suggested by oxford ragwort which in large quantities could cause damage to horse’s health.
Development of distinctive ecologies along route-ways
Railways- (animals able to make sets no human interference except leaves on the line) managed by humans to keep safe – distinctive
Motorways – rowan planted, 1.8 billion trees planted by highways agency, grasses (n-fertiliser) home for mice, kestrels feed on (M4 corridor) – distinctive managed to create environment.
Canals – (Kingfisher) human interaction only on paths – not distinctive due to invasion of climactic climax oak woodland due to NOT managed by humans, BUT could be distinctive as climactic climax itself is distinctive.
London Plane tree – uniform habitat form birds (aesthetically pleasing no shed bark) – distinctive
Changes in the rural-urban fringe
Changes in the rural urban fringe can result from development for example pressure for housing, recreational use development, as well as changes from urban blight caused by vandalism and neglect and lastly the development of conservation parks and areas.
Areas on the rural-urban fringe are typically green belt areas or close to green belt areas. This makes them desirable to developers as many people wish to live here due to its proximity to the countryside and not to far distance from urban areas such as that around London. In the South East of England 50K homes are needed in the next 10 years, a proposed area for this development is areas around the rural urban fringe due to this land prices are usually very high. Developments however, can damage the ecosystems and quality of farming land in many ways. Impermeable surfaces increase run off leading to the creating of bogs in low lying areas and compaction of the soil reduces the growth of plant roots and capacity for water to infiltrate through the soil. Acidation of the soil from pollutants during construction also reduces the nutrients available. The Sarum housing development for example built 640 new homes along an area previously considered to be green belt area. This not only imposed the damage caused by the construction of the houses but increased noise and air pollution and damage through infrastructure as well.
Development also has the potential to attract more people increasing counter-urbanisation and negatively impacting the environment. Urban blight is caused by vandalism such as fly tipping which also costs the government thousands to clear up each year, vandalism is also increasing in these areas increasing the damage to rural ecosystems and decreasing the aesthetically pleasing qualities about living on the fringe.
Urban blight is also caused by neglect all too often caused by farmers who anticipate the selling of their land. Recreational developments are increasing including golf courses which themselves often develop distinctive habitats.
Changes on the fringe can also have positive impacts to ecosystem as more areas are now being protected in government schemes such as that in Moors valley, south east England. The scheme has created a wildlife corridor and recreational space that attracts tourists, important to the local economy.
Local conservation area: Troopers Hill
