Ranunculus tripartitus
Ecology
An annual of shallow water bodies over base- and nutrient-poor substrates, in open sites which are flooded in winter but summer-dry. In S.E. England it is also found in pools in coppiced woodland. Lowland to 300 m at Belstone (N. Devon).
Status
Trends
Habitat destruction or reduced disturbance have led to the gradual decline of this species from the end of the 19th century onwards. However, it has recently been discovered at some new and historical British sites, and in 2000 it was refound in Ireland. Some mapped records may represent its hybrid with R. omiophyllus.
World Distribution
Oceanic Southern-temperate element.
Broad Habitats
Light (Ellenberg): 9
Moisture (Ellenberg): 10
Reaction (Ellenberg): 6
Nitrogen (Ellenberg): 3
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 5.2
July Mean Temperature (Celsius): 15.8
Annual Precipitation (mm): 1024
Height (cm): 9
Length: 25
Perennation - primary
Perennation - secondary
Life Form - primary
Woodiness
Clonality - primary
Count of 10km squares in Great Britain: 79
Count of 10km squares in Ireland: 1
Count of 10km squares in the Channel Isles: 0
Atlas Change Index: -1.09
Plantatt Conservation Status
JNCC Designations
RDB Species Accounts
Ranunculus tripartitus DC. (Ranunculaceae)
Three-lobed crowfoot, Crafanc Trillob
Status in Britain: VULNERABLE.
Status in Europe: Not threatened.
R. tripartitus occurs in shallow but seasonal bodies of water among heaths or related communities, especially shallow ditches and ponds, cart-tracks and gate-ways, wet in winter and spring but dry by summer. The soil base-status and pH are moderately high. Associates include Apium inundatum, Cicendia filiformis, Eleogiton fluitans, Juncus pygmaeus (Lizard peninsula), Lythrum portula, Pilularia globulifera, Potamogeton polygonifolius and a range of charophytes. Like other pond and trackway species of heaths and commons, R. tripartitus is intolerant of competition from other plant species, needing open sites maintained by fluctuating water levels, grazing and poaching by livestock, and disturbance by traffic.
It is typically a winter annual, though may sometimes perennate, germinating in autumn and flowering in April and May, or in mild winters as early as February - earlier than related species. Its sites often dry out completely by June. Wider dispersal of seed is likely be on the feet of birds and other animals.
R. tripartitus may be under-recorded, partly because of its early flowering, partly from problems of identification. R. tripartitus is very local and diminishing because of the destruction of heaths, the drainage or infilling of its habitats, and the cessation of grazing and disturbance which allows the uncontrolled growth of competitors and eventually Salix aurita and S. cinerea carr. However, the long viability of its seed allows it to recover if overgrown sites are cleared, provided drainage has not been too severe. R. tripartitus is frequent only in parts of the Lizard and in western Pembrokeshire. Some plants recorded as 'R. lutarius' in the New Forest are pentaploid hybrids between R. omiophyllus and R. tripartitus (R. x novae-forestae), and are frequently very similar in form to R. tripartitus (Cook 1966; Webster 1990). However, recent isoenzyme studies by Kay & John (1995) suggest that some New Forest populations should be regarded as the true species.
R. tripartitus is an oceanic-western European species, occurring from south-west Spain to northern Germany, and is also reported from Greece and Morocco (Jalas & Suominen 1989). It is declining throughout the northern part of its range.
A. J. Byfield, in Stewart, et al. (1994)
Scarce Atlas Account
Ranunculus tripartitus DC.
Three-lobed crowfoot
Status: scarce
R. tripartitus occurs in shallow but seasonal bodies of water among heaths or related communities, especially shallow ditches and ponds, cart-tracks and gate-ways, wet in winter and spring but dry by summer. The soil base-status and pH are moderately high. Associates include Apium inundatum, Cicendia filiformis, Eleogiton fluitans, Juncus pygmaeus (Lizard Peninsula only), Lythrum portula, Pilularia globulifera, Potamogeton polygonifolius and a variety of charophytes. Like other pond and trackway species of heaths and commons, R. tripartitus is intolerant of competition from other plant species, needing open sites maintained by fluctuating water levels, grazing and poaching by livestock, and disturbance by traffic.
Typically a winter annual, germinating in autumn and flowering in April and May, earlier than related species. Its sites often dry out completely by June.
R. tripartitus may be under-recorded, partly because of its early flowering, partly from problems of identification. Typical R. tripartitus is very local and diminishing through the destruction of heaths, draining or infilling of its habitats, and the cessation of grazing and disturbance which allow development of Salix aurita and S. cinerea. The long viability of its seed allows it to recover if overgrown sites are cleared, provided drainage has not been too severe. The Lizard Peninsula is the only area in Britain where R. tripartitus is at all frequent. Plants recorded as R. lutarius auct. in the New Forest are actually a pentaploid hybrid between R. omiophyllus and R. tripartitus (R. x novae-forestae); the presence of pure R. tripartitus in the New Forest has not been confirmed although some of these hybrids are very similar to it (Cook 1966; Webster 1990).
R. tripartitus is very local globally, occurring in north-western Europe from south-west Spain to northern Germany, and is also reported from Greece and Morocco (Jalas & Suominen 1989). It is declining throughout the northern part of its range.
A. J. Byfield
Atlas text references
Atlas (23b)
.
1984. Flora dels Països Catalans, I. Introducció. Licopodiàcies-Capparàcies.
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1988. The Irish Red Data Book. 1. Vascular Plants.
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2000. Three-lobed Water Crowfoot, Ranunculus tripartitus - report for 1999. Plantlife Report No. 157.
Jalas & Suominen (1989)
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1995. The conservation of scarce and declining plant species in lowland Wales: population genetics, demographic ecology and recommendations for future conservation in 32 species of lowland grassland and related habitats. (Science Report No. 110).
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1997. Aquatic plants in Britain and Ireland.
.
1994. Scarce plants in Britain.
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1999. British Red Data Books. 1. Vascular plants, edn 3.
Comment on Life Form