Key Terms: Ecosystems in the British Isles (AQA A Level Geography): Revision Note

Vegetation succession in the UK - key terms

Abiotic factors – Non-living environmental conditions (e.g. temperature, water, light, soil) that influence the development of ecosystems.

Bare rock (prisere) – The starting point of primary succession in a lithosere; colonised by pioneer species like lichens.

Biotic factors – Living elements of the ecosystem, such as plants and animals, which influence succession and ecosystem structure.

Climax community – The final, stable stage in ecological succession where vegetation is in dynamic equilibrium with the environment.

Decomposition – The breakdown of dead organisms and waste material into nutrients that enrich the soil.

Dynamic equilibrium – A stable state in ecosystems where species composition remains relatively unchanged over time, unless disturbed.

Embryo dune – The initial stage of sand dune formation in a psammosere, usually nearest the sea.

Halosere – Succession occurring in a saltwater environment, such as salt marshes.

Herbaceous plants – Soft, non-woody plants that typically appear in intermediate stages of succession.

Hydrosere – Succession that begins in a freshwater environment, such as a pond or lake, eventually forming woodland.

Lichen – A pioneer species capable of colonising bare rock; they secrete acids that weather rock and help create soil.

Lithosere – A succession process starting on bare rock, leading through several stages to a woodland climax community.

Mesophytic – A plant community adapted to neither very dry (xerophytic) nor very wet (hydrophytic) conditions.

Mosses – Grow after lichens, helping to build soil and outcompete earlier colonisers.

Pioneer species – The first organisms to colonise barren environments; they begin the soil-forming process and allow succession to progress.

Psammosere – A succession that occurs on sand dunes, progressing from fore dunes to mature dunes and climax vegetation.

Secondary succession – The redevelopment of vegetation following a disturbance (e.g. fire, deforestation) where soil already exists.

Seral stage – A step or stage in the sequence of succession leading to a climax community.

Sere – The entire sequence of communities that occupy a site through the process of succession.

Sub-climax – A community where succession has been interrupted by natural factors (e.g. soil, altitude), preventing full development.

Climatic climax in the UK - key terms

Ancient woodland – Forested areas that have existed for hundreds of years, often undisturbed and species-rich.

Ash woodland – Found in base-rich soils (e.g. limestone); includes a variety of shrub and ground species.

Broadleaf woodland – The UK’s dominant natural vegetation, consisting of deciduous trees like oak, beech, and elm.

Canopy – The top layer of woodland formed by mature tree crowns; site of most photosynthesis and primary productivity.

Caledonian forest – Native coniferous woodland mainly in Scotland, including Scots pine, birch, and juniper.

Deciduous woodland – A type of forest where trees shed their leaves seasonally; the natural climatic climax vegetation in much of the UK.

Detritivores – Organisms (e.g. earthworms, beetles) that decompose organic matter, enriching the soil with nutrients.

Layering – The vertical structure of woodlands, including the canopy, understory, and forest floor.

Temperate rainforest – A rare forest type in the UK found in high-rainfall coastal areas with low temperature variation.

Understory – The vegetation growing beneath the canopy layer; often includes shade-tolerant shrubs like hazel and holly.

Woodland floor – The ground layer where decomposition is most active due to low light and high humidity.

Wet woodland – Found on floodplains and waterlogged soils; includes species like willow and alder.

Human activity and succession - key terms

Afforestation – Planting trees in areas not previously forested, often with non-native species for commercial use.

Controlled burning – A land management technique to stimulate new plant growth and maintain open habitats like moorlands.

Deforestation – The removal of forest for timber, agriculture, or settlement, often halting succession and altering ecosystems.

Grazing – The feeding of livestock, which can prevent the growth of trees and shrubs, maintaining grassland or heathland.

Heather – A dominant species in heath and moorlands; adapted to acidic soils and managed through periodic burning.

Heather moorland – A managed plagioclimax ecosystem found in upland UK areas, sustained through burning and grazing.

Human interference – Activities such as burning, farming, and deforestation that arrest natural succession processes.

Moorland – Upland areas over 250m in altitude, typically wet and acidic, dominated by heather and mosses.

North York Moors – The largest heather moorland in England; an example of managed plagioclimax landscape maintained for biodiversity and economic activity.

Overgrazing – When too many animals feed on an area, reducing vegetation cover and altering succession pathways.

Plagioclimax – A community that has been permanently modified by human activity, preventing the natural climatic climax from being reached.

Secondary succession – The re-establishment of a plant community after a disturbance, which may or may not reach the original climax state.

Sub-climax – A vegetation stage held back by natural factors such as soil conditions or altitude rather than human activity.

Sustainable management – Practices such as rotational burning and regulated grazing that aim to maintain ecosystems like heathlands without degrading them.