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Microhabitat availability and seedling recruitment of Lobelia urens: a rare plant species at its geographical limit

Published online by Cambridge University Press:  22 February 2007

J.M. Dinsdale ,
M.P. Dale  and
M. Kent
J.M. Dinsdale
Affiliation:
Department of Biological Sciences, University of Plymouth, Drake's Circus, Plymouth PL4 8AA, UK
M.P. Dale
Affiliation:
Department of Biological Sciences, University of Plymouth, Drake's Circus, Plymouth PL4 8AA, UK
M. Kent*
Affiliation:
Department of Geographical Sciences, University of Plymouth, Drake's Circus, Plymouth PL4 8AA, UK
*
* Correspondence Fax: +44 1752 233054 Email: mkent@plymouth.ac.uk
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Abstract

In Britain, Lobelia urens (L.) (the heath lobelia) occurs in rough grassland, is rare and only found in southern England, where it is at the northern limit of its range. Emergence and survival of L. urens was investigated at six locations in two geographically distinct sites experiencing spring, autumn or no grazing in two consecutive years. Four factors were evaluated qualitatively, as a means of characterizing microhabitats for germination and survival: all permutations of higher plant cover, bryophytes, plant litter and surface depressions. The potential effect of adjacent plants on recruitment was also assessed using the nearest neighbour distance (NND). Grazing created depressions, removed plant litter and increased the proportion of sites with higher plant cover. It also resulted in a more open sward with higher NNDs. None of these changes stimulated recruitment. Instead, small increases in the frequency of some rare or very rare microhabitat types were vital in making grazed rough grassland more suitable for emergence. Reduced litter loads and a greater quantity of moss were two key responses. Overall, survival of L. urens was less than 1% and was particularly favoured by moss and an increase in NNDs. Shading from higher plants, with or without plant litter, decreased emergence, but the precise role of litter was complex and most probably related to its quantity. In an experimental seed bed, only empty depressions favoured emergence. The microhabitat relationships of L. urens were unusually consistent among locations and consecutive years. L. urens requires high soil surface temperatures but also adequate water for large scale recruitment, and such conditions are encouraged by grazing. The particular problems of experimental design and statistical analysis of data from recruitment experiments are also discussed.

Keywords

demographygrazingLobelia urensmicrohabitatrare plant conservation
Type
Research Article
Information
Seed Science Research , Volume 10 , Issue 4 , December 2000 , pp. 471 - 487
Copyright
Copyright © Cambridge University Press 2000

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References

Angevine, M.W. and Chabot, B.F. (1979) Seed germination syndromes in higher plants. pp. 188–206in Solbrig, O.T.; Jain, S.; Johnson, G.B.; Raven, P.H. (Eds) Topics in plant population biology. London, Macmillan Press.Google Scholar
Bewley, J.D. and Black, M. (1982) Physiology and biochemistry of seeds in relation to germination.Vol. 2. Viability, dormancy and environmental control. Berlin, Springer-Verlag.Google Scholar
Bodnaryk, R.P. and Lamb, R.J. (1991) Influence of seed size in canola, Brassica napus L. and mustard, Sinapis alba L., on seedling resistance against flea beetles, Phyllotreta cruciferae (Goeze). Canadian Journal of Plant Science 71, 397–404.CrossRefGoogle Scholar
Bonnot, E.J. (1971) Sur la place et le rôle des bryophytes dans la végétation des dunes. Colloque Phytosociologique 1, 149–155.Google Scholar
Boucher, C. (1981) Autecological and population studies of Orothamnus zeyheri in the Cape of South Africa. pp. 343–354in Synge, H. (Ed.) The biological aspects of rare plant conservation. New York, John Wiley and Sons.Google Scholar
Brightmore, D. (1968) Biological flora of the British Isles: Lobelia urens L. Journal of Ecology 56, 613–620.Google Scholar
Cavers, P.B. (1983) Seed demography. Canadian Journal of Botany 61, 3578–3590.Google Scholar
Chernov, Y.I. (1985) The living tundra. Cambridge, Cambridge University Press.Google Scholar
Clear Hill, B.H. and Silvertown, J. (1997) Higher order interaction between molluscs and sheep affecting seedling numbers in grassland. Acta Oecologia 18, 587–596.Google Scholar
Crawley, M.J. (1983) Herbivory: The dynamics of animal-plant interactions. Oxford, Blackwell Scientific Publications.Google Scholar
Cross, J.R. (1981) The establishment of Rhododendron ponticum in the Killarney oak woods, southwest Ireland. Journal of Ecology 69, 807–824.Google Scholar
Dale, M.P. and Causton, D.R. (1992) The ecophysiology of Veronica chamaedrys, V. montana and V. officinalis: I. Light quality and light quantity. Journal of Ecology 80, 483–492.Google Scholar
Darwin, C. (1859) On the origin of species. Cambridge, MA, Harvard University Press.Google Scholar
Deregibus, V.A., Casal, J.J., Jacobo, E.J., Gibson, D., Kauffman, M. and Rodriguez, A.M. (1994) Evidence that heavy grazing may promote the germination of Lolium multiflorum seeds via phytochrome-mediated perception of high red to far-red ratio. Functional Ecology 8, 536–543.Google Scholar
Dinsdale, J.M. (1996) The conservation and ecology of the heath lobelia (Lobelia urens L.). Ph.D. thesis, University of Plymouth.Google Scholar
Dinsdale, J., Dale, P. and Kent, M. (1997) The biogeography and historical ecology of Lobelia urens L. (the heath lobelia) in southern England. Journal of Biogeography 24, 153–175.Google Scholar
During, H.J. and van Tooren, B.F. (1990) Bryophyte interactions with other plants. Botanical Journal of the Linnean Society 104, 79–98.CrossRefGoogle Scholar
Eldridge, D.J., Westoby, M. and Holbrook, K.G. (1991) Soil surface characteristics, microtopography and proximity to mature shrubs: Effects on survival of several cohorts of Atriplex vesicaria seedlings. Journal of Ecology 79, 357–364.CrossRefGoogle Scholar
Facelli, J.M. and Pickett, S.T.A. (1991) Plant litter - its dynamics and effects on plant community structure. Botanical Review 57, 1–32.Google Scholar
Fenner, M. (1978) A comparison of the abilities of colonizers and closed turf species to establish from seed in artificial swards. Journal of Ecology 66, 953–963.Google Scholar
Fenner, M. (1985) Seed ecology. London, Chapman and Hall.Google Scholar
Fowler, N.L. (1988) What is a safe-site? Neighbour, litter, germination date and patch effects. Ecology 69, 947–961.Google Scholar
Goldberg, D.E. and Werner, P.A. (1983) The effects of size of opening in vegetation and litter cover on seedling establishment of goldenrods (Solidago sp.). Oecologia 60, 149–155.Google Scholar
Grubb, P.J. (1977) The maintenance of species-richness in plant communities: The importance of the regeneration niche. Biological Reviews 52, 107–145.CrossRefGoogle Scholar
Harper, J.L. (1977) Population biology of plants. London, Academic Press.Google Scholar
Harper, J.L., Clatworthy, J.N., McNaughton, I.H. and Sagar, G.R. (1961) The evolution and ecology of closely related species living in the same area. Evolution 15, 209–227.Google Scholar
Harper, J.L., Williams, J.T. and Sagar, G.R. (1965) The behaviour of seeds in the soil. I. The heterogeneity of soil surfaces and its role in determining the establishment of plants from seed. Journal of Ecology 53, 273–286.Google Scholar
Heydecker, W. (1973) Seed ecology. Pennsylvania, Pennsylvania State University Press.Google Scholar
Hutchings, M.J. and Booth, K.D. (1996) Studies on the feasibility of recreating chalk grassland vegetation on ex-arable land. II. Germination and early survivorship of seedlings under different management regimes. Journal of Applied Ecology 33, 1182–1190.CrossRefGoogle Scholar
Janzen, D.H. (1969) Seed-eaters versus seed size, number, toxicity and dispersal. Evolution 23, 1–27.Google Scholar
John, E. (1998) Interactions between mosses and vascular plants in chalk grassland. Bulletin of the British Ecological Society 29, 21–22.Google Scholar
Johnson, C.D. and Thomas, A.G. (1978) Recruitment and survival of seedlings of a perennial Hieracium species in a patchy environment. Canadian Journal of Botany 56, 572–580.Google Scholar
Jumpponen, A., Väre, H., Mattson, K.G., Ohtonen, R. and Trappe, J.M. (1999) Characterisation of ‘safe sites’ for pioneers in primary succession on recently deglaciated terrain. Journal of Ecology 87, 98–105.Google Scholar
Koller, D. (1972) Environmental control of seed germination. pp. 1–101in Kolzlowski, T.T. (Ed.) Seed biology, Vol. 2. New York, Academic Press.Google Scholar
Leishman, M.R. and Westoby, M. (1994) The role of large seed size in shaded conditions: Experimental evidence. Functional Ecology 8, 205–214.Google Scholar
Looman, J. (1964) Ecology of lichen and bryophyte communities in Saskatchewan. Ecology 45, 481–491.Google Scholar
Mallik, A.U., Hobbs, R.J. and Legg, C.J. (1984) Seed dynamics in Calluna-Arctostaphylos heath in northeastern Scotland. Journal of Ecology 72, 855–871.Google Scholar
Mayer, A.M. and Poljakoff-Mayber, A. (1982) The germination of seeds. (2nd edition) London, Pergamon Press.Google Scholar
Meredith, T.C. (1978) The ecology and conservation of Peucedanum palustre at Wicken Fen. Ph.D. thesis, Oxford University.Google Scholar
Rabotnov, T.A. (1969) Plant regeneration from seed in meadows of the USSR. Herbage Abstract 39, 269–277.Google Scholar
Reader, R.J. (1993) Control of seedling emergence by ground cover and seed predation in relation to seed size for some old field species. Journal of Ecology 81, 169–175.CrossRefGoogle Scholar
Rodwell, J.S. (1991) British plant communities. Vol. 2. Mires and heath. Cambridge, Cambridge University Press.Google Scholar
Sagar, G.R. and Harper, J.L. (1961) Controlled interference with natural populations of Plantago lanceolata, P. major and P. media. Weed Research 1, 163–176.Google Scholar
Sanson, G.D., Stolk, R. and Downes, B.J. (1995) A new method for characterising surface roughness and available space in biological systems. Functional Ecology 9, 127–135.Google Scholar
Scholefield, D. and Hall, D.M. (1985) A method to measure the susceptibility of pasture soils to poaching by cattle. Soil Use and Management 1, 134–138.CrossRefGoogle Scholar
Sheldon, J.C. (1974) The behaviour of seeds in soil. III. The influence of seed morphology and the behaviour of seedlings on the establishment of plants from surface lying seeds. Journal of Ecology 62, 47–66.CrossRefGoogle Scholar
Silvertown, J.W. (1981) Micro-spatial heterogeneity and seedling demography in species-rich grassland. New Phytologist 88, 117–128.CrossRefGoogle Scholar
Silvertown, J.W. (1987) Introduction to plant population ecology. (2nd edition) London, Longman.Google Scholar
Silvertown, J., Franco, M., Pisanty, I. and Mendoza, A. (1993) Comparative plant demography - relative importance of life-cycle components to the finite rate of increase in woody and herbaceous perennials. Journal of Ecology 81, 465–476.CrossRefGoogle Scholar
Silvertown, J. and Smith, B. (1989) Germination and population structure of spear thistle Cirsium vulgare in relation to experimentally controlled sheep grazing. Oecologia 81, 369–373.Google Scholar
Smith, M. and Capelle, J. (1992) Effects of soil surface microtopography and litter cover on germination, growth and biomass production of chicory (Cichorium intybus L.). American Midland Naturalist 128, 246–253.CrossRefGoogle Scholar
St. Clair, L.L., Webb, B.L., Johansen, J.R. and Nebeker, G.T. (1984) Cryptogamic soil crusts - enhancement of seedling establishment in disturbed and undisturbed areas. Reclamation and Revegetation Research 3, 129–136.Google Scholar
Suding, K.N. and Goldberg, D.E. (1999) Variation in the effects of vegetation and litter on recruitment across productivity gradients. Journal of Ecology 87, 436–449.Google Scholar
Winn, A.A. (1985) Effect of seed size and microsite on seedling emergence of Prunella vulgaris in four habitats. Journal of Ecology 73, 831–840.CrossRefGoogle Scholar