Search Screens: Descriptions of Characteristics


DEFINITION OF ELLENBERG'S INDICATOR VALUES
Ellenberg defined seven major scales, of which five are presented here. The two that are omitted, T (temperature) and K (continentality) correspond quite closely to the major biome and eastern limit categories defined for European distributions by Preston & Hill (1997). Neither T nor K values are satisfactory in an oceanic climate such as that of Britain; those for K are particularly unreliable, especially as Ellenbergs definition was geographical rather than climatic. We intend at a future date to calculate values for summer temperature, winter temperature and annual rainfall, based on the geographical distribution of species recorded by mapping schemes such as Atlas 2000 (Pearman & Preston 1996). The five scales have values defined as follows. A few species are given for each value by way of explanation.


7.14	L: Light (values for canopy tree species refer to preferences of the sapling stage of the life cycle)
	1	1 Plant in deep shade (no examples for GB). 2 3 4 5 6 7 8 9
	2	Between 1 and 3 (Epipogium aphyllum, Neottia nidus-avis, Trichomanes speciosum).
	3	Shade plant, mostly less than 5% relative illumination, seldom more than 30% illumination when trees are in full leaf (Galium odoratum, Listera cordata, Mercurialis perennis).
	4	Between 3 and 5 (Circaea lutetiana, Lamiastrum galeobdolum, Poa nemoralis).
	5	Semi-shade plant, rarely in full light, but generally with more than 10% relative illumination when trees are in leaf (Carex pendula, Hyacinthoides non-scripta, Primula vulgaris).
	6	Between 5 and 7 (Anthriscus sylvestris, Digitalis purpurea, Teucrium scorodonia).
	7	Plant generally in well lit places, but also occurring in partial shade (Arrhenatherum elatius, Carex flacca, Poa trivialis, Vicia cracca).
	8	Light-loving plant rarely found where relative illumination in summer is less than 40% (Cardamine hirsuta, Orchis morio, Thymus polytrichus, Vaccinium oxycoccus).
	9	Plant in full light, found mostly in full sun (Aster tripolium, Melilotus albus, Poa compressa, Primula farinosa).

7.15	F : Moisture (from the German Feuchtigkeit)
	1	Indicator of extreme dryness, restricted to soils that often dry out for some time (Corynephorus canescens, Helianthemum apenninum, Koeleria vallesiana).
	2	Between 1 and 3 (Clinopodium acinos, Saxifraga tridactylites, Sedum acre).
	3	Dry-site indicator, more often found on dry ground than in moist places (Asplenium trichomanes, Centaurea scabiosa, Spergularia rubra).
	4	Between 3 and 5 (Arctium minus, Helictotrichon pratense, Iris foetidissima, Thymus polytrichus).
	5	Moist-site indicator, mainly on fresh soils of average dampness (Anthriscus sylvestris, Euphorbia amygdaloides, Hyacinthoides nonscripta, Solanum nigrum).
	6	Between 5 and 7 (Agrostis stolonifera, Empetrum nigrum, Rumex crispus).
	7	Dampness indicator, mainly on constantly moist or damp, but not on wet soils (Carex ovalis, Dactylorhiza maculata, Pulicaria dysenterica, Ranunculus repens).
	8	Between 7 and 9 (Cardamine pratensis, Equisetum telmateia, Phalaris arundinacea, Schoenus nigricans).
	9	Wet-site indicator, often on watersaturated, badly aerated soils (Drosera rotundifolia, Myosotis scorpioides, Vaccinium oxycoccus, Viola palustris).
	10	Indicator of shallow-water sites that may lack standing water for extensive periods (Alisma plantago-aquatica, Carex limosa, Ranunculus lingua, Typha latifolia).
	11	Plant rooting under water, but at least for a time exposed above, or plant floating on the surface (Lemna minor, Nuphar lutea, Sagittaria sagittifolia, Schoenoplectus lacustris).
	12	Submerged plant, permanently or almost constantly under water (Isoetes lacustris, Potamogeton crispus, Ranunculus circinatus, Zostera marina).

7.16	R : Reaction (soil pH, or water pH)
	1	Indicator of extreme acidity, never found on weakly acid or basic soils (Andromeda polifolia, Lycopodium clavatum, Rubus chamaemorus, Ulex minor).
	2	Between 1 and 3 (Agrostis curtisii, Calluna vulgaris, Drosera rotundifolia, Polygala serpyllifolia).
	3	Acidity indicator, mainly on acid soils, but exceptionally also on nearly neutral ones (Agrostis vinealis, Dactylorhiza maculata, Galium saxatile, Pteridium aquilinum).
	4	Between 3 and 5 (Agrostis capillaris, Carex panicea, Juncus effusus, Teucrium scorodonia).
	5	Indicator of moderately acid soils, only occasionally found on very acid or on neutral to basic soils (Cardamine pratensis, Cirsium palustre, Rubus idaeus, Ulex europaeus).
	6	Between 5 and 7 (Ammophila arenaria, Carex sylvatica, Lolium perenne, Ranunculus ficaria).
	7	Indicator of weakly acid to weakly basic conditions; never found on very acid soils (Agrimonia eupatoria, Atriplex prostrata, Nuphar lutea, Phleum pratense).
	8	Between 7 and 9 (Artemisia vulgaris, Carduus nutans, Iris foetidissima, Viola hirsuta).
	9	Indicator of basic reaction, always found on calcareous or other high-pH soils (Bunium bulbocastanum, Clinopodium calamintha, Dryopteris submontana, Primula farinosa).

7.17	N : Nitrogen (in effect a general indicator of soil fertility)
	1	Indicator of extremely infertile sites (Agrostis curtisii, Clinopodium acinos, Drosera rotundifolia, Rubus chamaemorus).
	2	Between 1 and 3 (Aira praecox, Carex panicea, Linum catharticum, Scabiosa columbaria).
	3	Indicator of more or less infertile sites (Centaurea scabiosa, Galium saxatile, Pimpinella saxifraga, Teucrium scorodonia).
	4	Between 3 and 5 (Agrostis capillaris, Cirsium palustre, Plantago lanceolata, Primula vulgaris).
	5	Indicator of sites of intermediate fertility (Angelica sylvestris, Digitalis purpurea, Iris foetidissima, Trifolium pratense).
	6	Between 5 and 7 (Cirsium arvense, Glyceria fluitans, Poa trivialis, Rumex crispus).
	7	Plant often found in richly fertile places (Atriplex prostrata, Epilobium hirsutum, Stellaria media, Typha latifolia).
	8	Between 7 and 9 (Beta vulgaris, Galium aparine, Lamium album, Urtica dioica).
	9	Indicator of extremely rich situations, such as cattle resting places or near polluted rivers (Arctium lappa, Artemisia absinthium, Hyoscyamus niger, Rumex obtusifolius).

7.18	S : Salt (new definitions have been written for this account; definitions of Ellenberg et al. 1991, have a spurious accuracy).
	0	Absent from saline sites; if in coastal situations, only accidental and nonpersistent if subjected to saline spray or water (85% of the British flora).
	1	Slightly salt-tolerant species, rare to occasional on saline soils but capable of persisting in the presence of salt includes dune and dune-slack species where the ground water is fresh but where some inputs of salt spray are likely (Calystegia sepium, Chenopodium album, Oenanthe crocata, Sedum anglicum).
	2	Species occurring in both saline and nonsaline situations, for which saline habitats are not strongly predominant (Atriplex prostrata, Elytrigia repens, Phragmites australis, Rumex crispus).
	3	Species most common in coastal sites but regularly present in freshwater or on nonsaline soils inland (includes strictly coastal species occurring in sites such as cliff crevices and sand dunes that are not obviously salt-affected) (Cakile maritima, Cochlearia officinalis, Juncus gerardii, Spergularia rupicola). 45 6 7 8 9
	4	Species of salt meadows and upper saltmarsh, subject to at most only very occasional tidal inundation includes species of brackish conditions (ie of consistent but low salinity) (Atriplex littoralis, Elytrigia atherica, Glaux maritima, Triglochin maritimum).
	5	Species of the upper edge of saltmarsh, where not inundated by all tides includes obligate halophytes of cliffs receiving regular salt spray (Aster tripolium, Crithmum maritimum, Puccinellia maritima, Suaeda vera).
	6	Species of mid-level saltmarsh (Atriplex portulacoides, Cochlearia anglica, Limonium vulgare).
	7	Species of lower saltmarsh (Spartina anglica, Suaeda maritima).
	8	Species more or less permanently inundated in sea water (Zostera spp.).
	9	Species of extremely saline conditions, in sites where sea water evaporates, precipitating salt (Salicornia europaea agg. these could equally well be treated as species of the lower marsh).