Outline The Factors That Are Responsible For

Vegetation Change Over Time Essay, Research Paper

Vegetation develops in many different and varied

environments with each environment holding different effects on the flora

alteration over clip. This essay will analyze these different factors, in different

environments. It will analyze different sereal phases in different environment,

the lithosere or stone environment, the psammosere or sand environment, the

halosere or saltwater environment and hydrosere or fresh H2O environment. A sere is a phase of events by which the flora of an

country develops over clip. This begins with the innovator community and terminal with

the climatic flood tide flora. The first workss to colonize an country are called

the innovator community. The climatic flood tide flora is when the ultimate

flora development has taken topographic point and the environment has reached

equilibrium e.g. when the natural flora has reached a stable balance with

the clime and dirt of an country. As an environment goes through more sereal

stages the figure of species of workss will increase every bit will their tallness. The

island of Krakatoa in the Sundra sound between Java and Sumatra is a volcanic

island, which erupted in 1883. Its development was rapid merely taking

25 old ages to develop from the innovator community to climatic flood tide

flora because of the high humidness and temperatures and the rapid

weathering of the volcanic stone. The diagram below shows the manner an environment

such as Krakatoa develops.There are two types of sereal sequence primary and

secondary. Primary sereal sequence occurs on a new or antecedently unfertile

land. It occurs in four different types of environment lithosere, psammosere,

halosere and hydrosere. A lithosere is a stone environment. These are ab initio

colonised by bluish green bacteriums, which are wholly self-sufficing.

Therefore the innovator community is the mosses and lichens which are capable of

life in countries which lack dirt. The lichens and mosses help to endure the

stone along with other types of weathering. This along with the rotten affair

of mosses and lichens helps to organize a veneer of dirt, which can back up more

advanced works life. Seeds normally of grass so colonize this dirt as clip

passes the grasses will give manner to fast turning bushs which in bend will be

replaced by fast turning trees. Finally these will confront competition from slow

turning trees such as ash and oak. Although each phase of the sequence has

been superseded the flora from each old sereal phase still remains

but in smaller sums. Two illustrations of countries where the lithosereal development

has taken topographic point are Krakatoa and Sutsey. Sutsey is like Krakatoa in the fact

that it is a freshly formed island. The island was created after a volcanic

eruption on 14th November 1963. The island is located off the

south-western seashore of Iceland. Unlike Krakatoa it has non developed rapidly

because of the local clime which is highly cold and really blowy. These

conditions wear? t lead to the speedy constitution of life. The diagram below

shows a typical patterned advance for a lithosere ecosystem. Another type of sequence is one, which occurs on sand this

is known as a psammosere. The first colonizer of the sand are normally lyme

grass, sea vellication and maram grass these start dune formation known as embryo

dunes. The grasses easy move back from the high tide grade on to different

dunes. These dunes are really waterless and hence are normally merely populated by

maram grass which has adapted to the rough conditions. Further back from the

chief ridge are the older gray dunes, which are shelter from the air current and have

more humus in their dirt due to the increased decomposition of the maram grass.

This humus in the dirt supports different species and these start to interrupt the

maram grasses laterality on the dunes. Finally around 400m off from the sea the

climatic flood tide is reached as oak and ash trees develop. One illustration of a

psammosere is Camber Sands, which has developed over clip to hold a full

diverseness of workss on the different dunes. The diagram below shows the

development of the environment in a psammosere.Freshwater lakes and pools are known as hydrosere

environments. These besides develop through sereal phases. The innovator colonizer

is normally algae and mosses whose spores have been blown on to the H2O

surface. These grow to organize flora tonss, which so back up other life

such as bacteriums and insects. The following colonizers are the H2O loving workss,

which may turn on the H2O surface like lilies or may turn wholly

submerged. Bacteria recycle foods from these workss promoting the

invasion of workss such as cat’s-tails. The increased deposit created by the

decomposition of these works leads to increased deposit, which continues to in

make full the lake. Over clip the marsh countries at the border of the lake will be

colonised by little trees and bushs. And eventually the lake is wholly in

filled as a consequence of the deposit construct up. When this occurs the oak and ash

trees will be able to take root and the climatic flood tide flora will be

reached. An illustration of an country where this is happening is the Norfolk Broads

where some of the broads are about wholly in filled whereas others are

still at the first phase of development. The diagram below shows the different

phases in the development of a hydrosere.Haloseres are environment based in a salt-water environment

normally at the oral cavity of a river where there is a big sum of silt and clay

deposition. The innovator colonizers are algae, which can stand being submerged

in Washington

ter for the twelve-hour high tide period. These trap clay doing it to

accumulate. Spartina townsendii is

the following colonizer. It can digest saline conditions and grows on the sloven

zone with merely four hours of O in every twelve-hour period. In contrast

the turf zone is inhabited by workss, which can merely be submerged for four

hours in every 12 hours. The dominant species here are sea lavender and

grasses. The upper turf zone is merely covered by the high spring tides leting

different types of workss to set up. Further inland from here different

types of workss grow including grasses and bushs followed by little trees and

finally ash and oak trees. The Medway estuary is one illustration of an country

where this type of patterned advance is taking topographic point. The diagram below shows the

primary sequence of a typical halosere.When a climatic flood tide occurs this means that the ecosystem

or biome is in a province of equilibrium with a stableness of transportations material

and energy. However the are a figure of factors which can collar the

development of the ecosystem before it has reached it dynamic equilibrium.

These include mudflow, landslide, disease or altering clime. One illustration is a

fire, which is likely to destruct the whole ecosystem. But it does let for new

development as the ash created increase the alimentary quality of the dirt

dramatically. But it does go forth the dirt more vulnerable to eroding. Some

ecosystems depend on a fire to unclutter the country and to let the growing of new

seedlings, which will boom in the good quality dirt with small or no

competition for visible radiation. Some illustrations of ecosystems, which depend on a fire to

allow growing, are the wood of the Australian shrub. There are three factors, which will dramatically consequence the

flora alteration over clip in an ecosystem. These are clime, dirt quality

and H2O handiness. If the clime that an ecosystem is developing in is

harsh such as that on Sutsey so flora alteration will be slow and really

hard whereas if the clime is ideal so the ecosystem will develop

rapidly such as that on Krakatoa. The dirt quality is of import because the

figure of foods in a dirt will impact the type of workss able to turn

at that place. A hapless quality dirt will merely be able to back up a little sum of little

workss whereas a good quality dirt will back up larger workss. Water

handiness is cardinal because it affects the figure of workss which can turn in a

certain country. If there is small H2O available so merely a few workss can

survive. In contrast if there is an copiousness of H2O so the figure of

workss able to be supported will be big. This can besides be taken to another

extreme where there is excessively much H2O and the workss drown. Human factors are major collaring factors, which normally

lead to secondary. These can include deforestation, which leads to the remotion

of many of the foods from the ecosystem and can take to erosion. This has

occurred in the Gola forest in Sierra Leone. Sierra Leone has a clime, which

would let a high proportion of it s land mass to be covered with rain forest.

But due to changeless deforestation the rain forest has been dramatically reduced

in size and now merely covers a little sum of the land. Pollution caused by worlds can impact flora on three different

graduated tables globally, nationally and locally. An illustration of a planetary pollution,

which affects flora alteration, is acerb rain, which via air currents can

travel globally precipitating at any point of the universe. Acid rain putting to deaths workss

and can alter the balance of foods in the dirt favoring certain types of

workss. An illustration of pollution on a national graduated table is planetary warming which can

affect whole states and leads to the deceases of many workss and the addition

H2O degrees around the universe. Trampling is an illustration of pollution on a local

graduated table. Trampling putting to death workss and leads to the compacting of dirts doing H2O

soaking up hard and works growing therefore hard. Other illustrations of Human collaring factors, which affect

flora alteration over clip, include desertification the imperfect

downgrading of land normally caused by human misdirection through things like

over graze or via drouth. Urbanization and the gradual enlargement of towns

into the countryside in Great Britain and other states has led to the

devastation of ecosystems to let infinite for enlargement. This is peculiarly

true in less economically developed states, which are in a phase of hyper

urbanization and make infinite for this by destructing ecosystems. One illustration of

this is Mexico City, which has experienced monolithic enlargement in recent old ages. Conservation is another manner in which worlds can impact the

natural flora alteration. The Norfolk Broads is a good illustration of this. The

Norfolk Broads country has been an country of preservation for a figure of old ages the

country houses a figure of rare species of works and animate being which environmentalists

are seeking to salvage. One thing they are seeking to forestall is the gradual in

filling of the broads. This therefore disrupts the natural flora alteration. A

policy of aforestation has been applied in a figure of countries to seek and

repopulate certain countries with trees that were one time at that place. This therefore has a

big consequence on the flora alteration over clip. In decision we can see that there are many different

things, which affect flora alteration over clip. These are both physical

factors and human factors and both types have the power to wholly alter an

ecosystem impact its patterned advance towards its climatic flood tide flora and its

constitution as a biome.