Data Records

In phytosociology, the data of a single plot are called a releve (French for record, see Table 1), which consists of 'header' and species data. The 'header' comprises plot identification, methodological information, and metric, ordinal, or categorical data on geographic position, environmental conditions, and overall vegetation structure. Some of these data are essential, others optional, depending on the purpose and resources of a project (Table 2).

The species data are composed of a list of plant taxa (species and infraspecific taxa; further referred to as 'species') and their attributes. A full releve lists all plant species occurring in the plot and growing on soil, including bryophytes, lichens, and macroalgae. Additional recording of species growing on substrata other than soil, such as on living plants (epiphytes), rocks (saxicolous plants), or dead wood (lignicolous plants), is desirable, but not standard in phytosociology. Every species observation is assigned to a vertical stratum (e.g., tree layer, shrub layer, herb layer, and cryptogam layer). Woody species occurring in different layers are recorded separately for each layer. For each species observation in a layer, an importance value is estimated and usually expressed on a simplified scale of abundance (number of individuals/ ramets) and/or cover (area of the vertical projection of all aerial parts of a species relative to the total plot area) (Table 3). As mixed cover-abundance scales pose problems in data analysis, pure cover scales are preferred when precise quantitative estimates are required, for

Table 1 Example of a forest releve with five vegetation layers distinguished: upper tree layer (T1), lower tree layer (T2), shrub layer (S), herb layer (H), and cryptogam layer (C)

Plot ID/methodology

Geographic data

UTM coordinates 32 U 4434393 E - 5272800 N

Locality Ettaler Manndl, Höllenstein, 3 km W from

Eschenlohe,

Garmisch-Partenkirchen, Bavaria, Germany

Environmental data

Structural data

Cover cryptogam layer (%) 3

Layer Species Importance Layer Species Importance

T1 Fagus sylvatica 3 H Oxalis acetosella 2

Picea abies 3 Paris quadrifolia +

Polypodium vulgare +

T2 Picea abies 1 Prenanthes purpurea +

Primula elatior +

S Picea abies 1 Ranunculus lanuginosus 1

Rumex alpestris +

H Acer pseudoplatanus + Salvia glutinosa 1

Aconitum vulparia + Sanicula europaea +

Adenostyles alliariae 1 Saxifraga rotundifolia 1

Adoxa moschatellina + Senecio fuchsii 1

Athyrium filix-femina + Stellaria nemorum 2

Cardamine flexuosa + Thelypteris limbosperma +

Chaerophyllum hirsutum + Veronica urticifolia +

Chrysosplenium alternifolium + Viola biflora +

Cicerbita alpina +

Deschampsia cespitosa + C Atrichum undulatum 1

Dryopteris dilatata + Brachythecium rutabulum +

Dryopteris filix-mas + Conocephalum conicum +

Epilobium montanum + Ctenidium molluscum +

Galeopsis tetrahit + Dicranella heteromalla +

Galium odoratum + Dicranum scoparium +

Geranium robertianum + Fissidens taxifolius +

Gymnocarpium dryopteris + Mnium spinosum +

Impatiens noli-tangere + Plagiochila porelloides +

Lamiastrum montanum 1 Plagiomnium undulatum +

Luzula sylvatica subsp. sieberi + Plagiothecium curvifolium +

Lysimachia nemorum 1 Polytrichum formosum +

Mercurialis perennis + Rhizomnium punctatum +

Mycelis muralis 1 Thuidium tamariscinum +

Myosotis sylvatica +

Table 2 Essential (*) and selected optional data to be included in the 'header' of a phytosociological releve

Group

Data

Comment

ID/methodology Field number*

Author(s)* Plot size* Plot shape Sampling date*

Preliminary assignment to a syntaxon Geographic data Geographic coordinates*

Locality in textual form*

For example, Greenwich coordinates, UTM including political and/or natural geographic units

Environmental data

Structural data

Elevation (m a.s.l.)* Slope aspect* Inclination* Soil

Geology (parent material) Management

Height of vegetation layers (m) Cover of vegetation layers (%)* Cover of other surfaces (%)

For example, type, texture, depth, pH, humus form, humus content, C/N ratio

For example, tree layer, shrub layer, herb layer, cryptogam layer Cover of each layer and total cover

For example, bare soil, litter, woody debris, rocks, open water

Table 3 Customary version of an extended Braun-Blanquet cover-abundance scale with ordinal values, which are often used for numerical interpretation. In the original Braun-Blanquet scale, 2m, 2a, and 2b were joined under the symbol '2'

Cover

Abundance (number of

interval

Ordinal

Symbol

individuals/ramets)

(%)

value

r

1

0-5

1

+

2-5

0-5

2

1

6-50

0-5

3

2m

More than 50

0-5

4

2a

Any

5-12.5

5

2b

Any

12.5-25

e

3

Any

25-50

7

4

Any

50-75

a

5

Any

75-100

9

example, in studies of vegetation change in permanent plots. Sometimes, additional characteristics of the species - such as sociability (degree of clustering of the individuals), vitality, fertility, age class (e.g., seedling or juvenile), and phenological status - are recorded, but these are of little or no importance for standard analyses.

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