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National vegetation classification (NVC)
Ecology And Biodiversity
Bath Spa University
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National vegetation classification (NVC)
Aims
•Understand the rationale behind the NVC •NVC Community Types •Applying NVC in the field •Preparing Floristic Tables •Using MAVIS to identify sample communities •Relationship between Phase 1 Habitat Surveys and the NVC •Future developments
Ecological Theory - Plant Community Ecology
•Concept of plant community ecology underpins NVC •Species rich plant communities – significant biodiversity resource (declining) •All plants require the same resources, which are often limited •Results in competitive exclusion – only best competitors survive •But in real world large numbers of species co-exist?
Concept of Ecological Niche and Competition theory
•Resource based competition theory: predicts stable co-existence between species dependant on each being superior competitor in its own niche •Theoretical solution (central to community ecology) requires a degree of niche separation in time or space •Niche separation leads to community structure which can be observed in the field and measured Hutchinson G. (1957) Concluding Remarks. Cold Spring Harbour Symposia on Quantitative Biology, 22:pp 415- 422.
Phytosociology - The science of vegetation
Study of plant communities: •Structure, Composition & physiognomy (layering, species present & how it looks) •Development & Change – Morphology & Succession •Relationship between species within communities (competition) •Relationships between plants and physical/chemical environment •Climate •Edaphic (soils) •Moisture •Biotic factors e. grazing
Phytosociological Approach of NVC
•Survey of complete range of variation within a community •Described communities represent the ‘typical’ community •Method of fitting unknown samples (stands) within the classification system •New stands of vegetation sampled from sites outside the original data collection sites can be related to the ‘typical’ samples •Keys to vegetation types published in volumes to aid classification
Why did we need the NVC?
•Classification underpins knowledge & understanding of natural world •Allows communication between ecologists worldwide •Important tool for nature conservation – need to identify & record species, ecological communities and habitat types that are threatened •Relate this to the legal framework to ensure protection •Species taxonomy is well developed •Classification of habitats and communities a more recent science
Brief history
•Comprehensive classification & description of plant communities of GB, commissioned in 1975, co-ordinated by John Rodwell at Lancaster •Originally developed for UK conservation agencies •Resulted in production of maps and inventories of plant communities in designated and threatened sites •Systematically arranged with standardised descriptions •12 major vegetation types, 286 plant communities, 578 sub-communities •Provides a common standard •Sold over 10,000 copies
What does the NVC cover?
The NVC is a detailed phytosociological classification, which assesses the full suite of vascular plant, bryophyte and macro-lichen species within a certain vegetation type. It is based on about 35,000 samples of vegetation, the distribution of which is shown in the map left. These cover nearly all natural, semi-natural and a number of major artificial vegetation communities in terrestrial, freshwater and maritime situations across Great Britain (but not Northern Ireland). Important Information! •Extended to become the accepted standard method for terrestrial plant community classification for detailed (Phase 2) ecological site survey & assessment •Predictive capacity – pathway of ecological succession under set of environmental
Floristic Tables
•Each community/sub-community defined by a combination of frequency and abundance values for species identified in the samples •Derived using multivariate analysis techniques •Floristic tables organise and summarise the floristic variation in the sample •Includes all vascular plants, bryophytes and macro-lichens with a frequency of >5% in any one of the sub-communities (or for vegetation types with no sub-communities within the community as a whole) •Species are arranged in blocks to indicate their pattern of occurrence through the community, ordered by decreasing frequency •Example MG5 Cynosurus cristatus-Centaurea nigra mesotrophic grassland
Using MAVIS to classify ‘new’ NVC samples
ceh.ac/services/modular-analysis-vegetation-information-system-mav •MAVIS software analyses vegetation data using different types of classification systems •Includes the Countryside Vegetation System (CVS) and classifications used by the Countryside Survey 2000 •MAVIS also includes classification programmes for the National Vegetation Classification (NVC) More about this in subsequent workshop sessions...
•Important that the standard field method is used when sampling your own sites •Usually follows on from Phase 1 where there is some conservation interest •Software available to help analyse NVC data •More in subsequent workshops where we will look at our own data collected on the field course to develop a Phase 1 Habitat map, NVC classification of plant communities and prepare for first assignment in this module
National vegetation classification (NVC)
Module: Ecology And Biodiversity
University: Bath Spa University
- Discover more from:Ecology And BiodiversityBath Spa University19 Documents
- More from:Ecology And BiodiversityBath Spa University19 Documents
