Plagio climax community
Encyclopedia
A Plagio climax community is an area or habitat
in which the influences of the human race, have prevented the ecosystem from developing further. The ecosystem may have been stopped from reaching its full climatic climax or deflected towards a different climax by activities such as:
Each of these are known as arresting factors.
In each case, human activity has led to a community which is not the climax community
expected in such an area. If the human activity continues, the community will be held in a stable position and further succession will not occur until the human activity ceases.
system where the impact of the human race has caused footpath erosion
to occur, affecting the vegetation
so that feet trampling on the dune plants eventually destroys them.
The uplands of Northern England
were once covered by deciduous
woodland. Some heather
would have been present, but in relatively small amounts. Gradually the forests were removed during the early Middle Ages
for timber
and fuel
purposes, and to create space for agricultural
activities. The soil
deteriorated as a result and heather came to dominate the plant community. Sheep grazing
was the major form of agriculture in the area at the time and the sheep prevented the re-growth of woodland by destroying any young saplings.
In more recent times the process of controlled burning of the heather has taken place. The heather is burnt after 15 years of its life cycle before it becomes mature and allows colonisation
of the area by other plants. The ash adds to the soil fertility and the new growth that results increase the productivity of the ecosystem and provides the sheep with a more nutritious diet than is provided by the elder heather. This controlled burning maintains a plant community which is not the climatic climax of the area, and is therefore a plagioclimax.
In Studland
Heath in Dorset, England, the management agency prevents the climax community (in this case trees) becoming established. At Studland the aim is to keep the area as heathland, so that the small reptiles that inhabit the dune system continue to survive. If the area is allowed to develop naturally into woodland, the reptiles would be replaced by other species of animals.
Another good example of a plagio climax community is Braunton Burrows
, England
.
Habitat (ecology)
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...
in which the influences of the human race, have prevented the ecosystem from developing further. The ecosystem may have been stopped from reaching its full climatic climax or deflected towards a different climax by activities such as:
- Cutting down the existing vegetationVegetationVegetation is a general term for the plant life of a region; it refers to the ground cover provided by plants. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic characteristics. It is broader...
- BurningSlash and burnSlash-and-burn is an agricultural technique which involves cutting and burning of forests or woodlands to create fields. It is subsistence agriculture that typically uses little technology or other tools. It is typically part of shifting cultivation agriculture, and of transhumance livestock...
as a means of forest clearanceDeforestationDeforestation is the removal of a forest or stand of trees where the land is thereafter converted to a nonforest use. Examples of deforestation include conversion of forestland to farms, ranches, or urban use.... - Planting trees or crops
- GrazingGrazingGrazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
and trampling by domesticated animalAnimalAnimals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...
s - Harvesting of planted crops
Each of these are known as arresting factors.
In each case, human activity has led to a community which is not the climax community
Climax community
In ecology, a climax community, or climatic climax community, is a biological community of plants and animals which, through the process of ecological succession — the development of vegetation in an area over time — has reached a steady state. This equilibrium occurs because the climax community...
expected in such an area. If the human activity continues, the community will be held in a stable position and further succession will not occur until the human activity ceases.
Examples
An example may be in a beach duneDune
In physical geography, a dune is a hill of sand built by wind. Dunes occur in different forms and sizes, formed by interaction with the wind. Most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter "slip face" in the lee of the wind...
system where the impact of the human race has caused footpath erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...
to occur, affecting the vegetation
Vegetation
Vegetation is a general term for the plant life of a region; it refers to the ground cover provided by plants. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic characteristics. It is broader...
so that feet trampling on the dune plants eventually destroys them.
The uplands of Northern England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
were once covered by deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
woodland. Some heather
Calluna
Calluna vulgaris is the sole species in the genus Calluna in the family Ericaceae. It is a low-growing perennial shrub growing to tall, or rarely to and taller, and is found widely in Europe and Asia Minor on acidic soils in open sunny situations and in moderate shade...
would have been present, but in relatively small amounts. Gradually the forests were removed during the early Middle Ages
Middle Ages
The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...
for timber
Timber
Timber may refer to:* Timber, a term common in the United Kingdom and Australia for wood materials * Timber, Oregon, an unincorporated community in the U.S...
and fuel
Fuel
Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...
purposes, and to create space for agricultural
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
activities. The soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
deteriorated as a result and heather came to dominate the plant community. Sheep grazing
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
was the major form of agriculture in the area at the time and the sheep prevented the re-growth of woodland by destroying any young saplings.
In more recent times the process of controlled burning of the heather has taken place. The heather is burnt after 15 years of its life cycle before it becomes mature and allows colonisation
Ecological succession
Ecological succession, is the phenomenon or process by which a community progressively transforms itself until a stable community is formed. It is a fundamental concept in ecology, and refers to more or less predictable and orderly changes in the composition or structure of an ecological community...
of the area by other plants. The ash adds to the soil fertility and the new growth that results increase the productivity of the ecosystem and provides the sheep with a more nutritious diet than is provided by the elder heather. This controlled burning maintains a plant community which is not the climatic climax of the area, and is therefore a plagioclimax.
In Studland
Studland
Studland is a small village on the Isle of Purbeck in the English county of Dorset. It is famous for its beaches and nature reserve. In 2001 Studland had a population of 480, the lowest in 50 years...
Heath in Dorset, England, the management agency prevents the climax community (in this case trees) becoming established. At Studland the aim is to keep the area as heathland, so that the small reptiles that inhabit the dune system continue to survive. If the area is allowed to develop naturally into woodland, the reptiles would be replaced by other species of animals.
Another good example of a plagio climax community is Braunton Burrows
Braunton Burrows
Braunton Burrows is a sand dune system on the North Devon coast. Braunton Burrows is a prime British sand dune site, the largest sand dune system in England. It is particularly important ecologically because it includes the complete successional range of dune plant communities, with over 400...
, England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
.