Reduced Fecundity in Small Populations of the Rare Plant Gentianopsis ciliate (Gentianaceae)

Abstract

Habitat destruction is the main cause for the biodiversity crisis. Surviving populations are often fragmented, i.e., small and isolated from each other. Reproduction of plants in small populations is often reduced, and this has been attributed to inbreeding depression, reduced attractiveness for pollinators, and reduced habitat quality in small populations. Here we present data on the effects of fragmentation on the rare, self-compatible perennial herb Gentianopsis ciliata (Gentianaceae), a species with very small and presumably well-dispersed seeds. We studied the relationship between population size, plant size, and the number of flowers produced in 63 populations from 1996 - 1998. In one of the years, leaf and flower size and the number of seeds produced per fruit was studied in a subset of 25 populations. Plant size, flower size, and the number of seeds per fruit and per plant increased with population size, whereas leaf length and the number of flowers per plant did not. The effects of population size on reproduction and on flower size remained significant if the effects were adjusted for differences in plant size, indicating that they could not be explained by differences in habitat quality. The strongly reduced reproduction in small populations may be due to pollination limitation, while the reduced flower size could indicate genetic effects.

Fecundity - Gentianopsis ciliata - habitat fragmentation - rare species - population size - reproduction.

References

• 1 Blarer A., Keasar T., Shmida A.. Possible mechanisms for the formation of flower size preferences by foraging bumblebees.  Ethology. (2002);  108 341-351
• 2 Breslow N. E., Clayton D. G.. Approximate inference in generalized linear mixed models.  Journal of the American Statistical Association. (1993);  88 9-25
• 3 Conner J. K., Rush S.. Effects of flower size and number on pollination visitation to wild radish, Raphanus raphanistrum. .  Oecologia. (1996);  105 509-516
• 4 Dierschke H.. Untersuchungen zur Populationsdynamik der Gentianella-Arten in einem Enzian-Zwenken-Kalkmagerrasen.  Natur und Heimat. (1986);  46 73-81
• 5 Dowlen C. M., Ho T. N.. Gentianella ciliata (L.) Borkh. in Wiltshire.  Watsonia. (1995);  20 279
• 6 Dudash M. R.. Plant size effects on female and male function in hermaphroditic Sabatia angularis (Gentianaceae).  Ecology. (1991);  72 1004-1012
• 7 Fischer M., Matthies D.. Mating structure and inbreeding and outbreeding depression in the rare plant Gentianella germanica (Gentianaceae).  American Journal of Botany. (1997);  84 1685-1692
• 8 Fischer M., Matthies D.. RAPD variation in relation to population size and plant performance in the rare Gentianella germanica. .  American Journal of Botany. (1998 a);  85 811-819
• 9 Fischer M., Matthies D.. The effect of population size on performance in the rare plant Gentianella germanica. .  Journal of Ecology. (1998 b);  86 195-204
• 10 Garve E.. Atlas der gefährdeten Farn- und Blütenpflanzen in Niedersachsen und Bremen. Kartierung 1982 - 1992.  Naturschutz und Landschaftspflege in Niedersachsen. (1994);  30 1-895
• 11 Groom M. J.. Allee effects limit population viability of an annual plant.  American Naturalist. (1998);  151 487-496
• 12 Hess D.. Alpenblumen. Erkennen - Verstehen - Schützen. Stuttgart; Ulmer (2001)
• 13 Holsinger K. E.. Demography and extinction in small populations. Young, A. G. and Clarke, G. M., eds. Genetics, Demography and Viability of Fragmented Populations. Cambridge; Cambridge University Press (2000): 55-74
• 14 Huenneke L. F.. Ecological implications of genetic variation in plant populations. Falk, D. A. and Holsinger, K. E., eds. Genetics and Conservation of Rare Plants. New York; Oxford University Press (1991): 31-44
• 15 Jäger E., Werner K.. Rothmaler - Exkursionsflora von Deutschland. Bd. 2: Gefäßpflanzen: Grundband, 18. Aufl. Heidelberg; Spektrum Akademischer Verlag (2002)
• 16 Jennersten O.. Pollination in Dianthus deltoides (Caryophyllaceae): effects of habitat fragmentation on visitation and seed set.  Conservation Biology. (1988);  2 359-366
• 17 Kelly D.. Seeds per fruit as function of fruits per plant in depauperate annuals and biennials.  New Phytologist. (1984);  96 103-114
• 18 Kéry M.. Ecology of small populations. PhD thesis, Universität Zürich. (2000)
• 19 Kéry M., Matthies D., Spillmann H.-H.. Reduced fecundity and offspring performance in small populations of the declining grassland plants Primula veris and Gentiana lutea. .  Journal of Ecology. (2000);  88 17-30
• 20 Kéry M., Matthies D., Fischer M.. The effect of plant population size on the interactions between the rare Gentiana cruciata and its specialized herbivore Maculinea rebeli. .  Journal of Ecology. (2001);  89 418-427
• 21 Kéry M., Matthies D., Schmid B.. Demographic stochasticity in population fragments of the declining distylous perennial Primula veris (Primulaceae).  Basic and Applied Ecology. (2003);  4 197-206
• 22 Knipe P. R.. Gentianella ciliata (L.) Borkh. in Buckinghamshire.  Watsonia. (1988);  17 94-95
• 23 Korneck D., Sukopp H.. Rote Liste der in der Bundesrepublik Deutschland ausgestorbenen, verschollenen und gefährdeten Farn- und Blütenpflanzen und ihre Auswertung für den Arten- und Biotopschutz.  Schriftenreihe für Vegetationskunde. (1988);  19 1-210
• 24 Korneck D., Schnittler M., Vollmer I.. Rote Liste der Farn- und Blütenpflanzen (Pteridophyta et Spermatophyta) Deutschlands.  Schriftenreihe für Vegetationskunde. (1996);  28 21-187
• 25 Kutschera L., Lichtenegger E.. Wurzelatlas mitteleuropäischer Grünlandpflanzen. Stuttgart; Gustav Fischer Verlag (1982 - 1992)
• 26 Lamont B. B., Klinkhamer P. G. L., Witkowski E. T. F.. Population fragmentation may reduce fertility to zero in Banksia goodii - a demonstration of the Allee effect.  Oecologia. (1993);  94 446-450
• 27 Landolt E.. Gefährdung der Farn- und Blütenpflanzen in der Schweiz. Bern; Bundesamt für Umwelt, Wald und Landschaft (1991)
• 28 Lauber K., Wagner G.. Flora Helvetica. Bern; Verlag Paul Haupt (1996)
• 29 Matthies D.. The genetic and demographic consequences of habitat fragmentation for plants: examples from declining grassland species. Klingenstein, F., and Wingender, R., eds. Erfassung und Schutz der genetischen Vielfalt von Wildpflanzenpopulationen in Deutschland. Bonn-Bad Godesberg, Bonn; Bundesamt für Naturschutz (2000): 129-140
• 30 Matthies D., Bräuer I., Maibom W., Tscharntke T.. Population size and the risk of local extinction: empirical evidence from rare plants.  Oikos. (2004);  105 481-488
• 31 Menges E. S.. The application of minimum viable population theory to plants. Falk, D. A. and Holsinger, K. E., eds. Genetics and Conservation of Rare Plants. New York; Oxford University Press (1991): 47-61
• 32 Menges E. S.. Evaluating extinction risks in plant populations. Fiedler, P. L. and Kareiva, P. M., eds. Conservation Biology for the Coming Decade. New York; Chapman and Hall (1998): 49-65
• 33 Meusel H., Jäger E., Weinert E.. Vergleichende Chorologie der zentraleuropäischen Flora. Jena; Gustav Fischer Verlag (1978)
• 34 Moody-Weis J. M., Heywood J. S.. Pollination limitation to reproductive success in the Missouri evening primrose, Oenothera macrocarpa (Onagraceae).  American Journal of Botany. (2001);  88 1615-1622
• 35 Morgan J. W.. Effects of population size on seed production and germinability in an endangered, fragmented grassland plant.  Conservation Biology. (1999);  13 266-273
• 36 Müller-Stoll W. R.. Ökologische Untersuchungen an Xerothermpflanzen des Kraichgaus.  Zeitschrift für Botanik. (1935);  29 161-253
• 37 Oostermeijer J. G. B.. Threats to rare plant persistence. Brigham, C. A. and Schwartz, M. W., eds. Population Viability in Plants: Conservation, Management, and Modeling of Rare Plants. Berlin, Heidelberg; Springer-Verlag (2003): 17-58
• 38 Oostermeijer J. G. B., den Nijs J. C. M., Raijmann L. E. L., Menken S. B. J.. Population biology and management of the marsh gentian (Gentiana pneumonanthe L.), a rare species in The Netherlands.  Botanical Journal of the Linnean Society. (1992);  108 117-130
• 39 Oostermeijer J. G. B., van Eijck M. W., den Nijs J. C. M.. Offspring fitness in relation to population size and genetic variation in the rare perennial plant species Gentiana pneumonanthe (Gentianaceae).  Oecologia. (1994);  97 289-296
• 40 Oostermeijer J. G. B., Luijten S. H., Ellis-Adam A. C., den Nijs J. C. M.. Future prospects for the rare, late-flowering Gentianella germanica and Gentianopsis ciliata in Dutch nutrient-poor calcareous grasslands.  Biological Conservation. (2002);  104 339-350
• 41 Ouborg N. J., van Treuren R.. The significance of genetic erosion in the process of extinction. IV. Inbreeding load and heterosis in relation to population size in the mint Salvia pratensis. .  Evolution. (1994);  48 996-1008
• 42 Ouborg N. J., van Treuren R.. Variation in fitness-related characters among small and large populations of Salvia pratensis. .  Journal of Ecology. (1995);  83 369-380
• 43 Paschke M., Abs C., Schmid B.. Effects of population size and pollen diversity on reproductive success and offspring size in the narrow endemic Cochlearia bavarica (Brassicaceae).  The American Journal of Botany. (2002);  89 1250-1259
• 44 Payne R. W., Lane P. W., Digby P. G. N., Harding S. A., Leech P. K., Morgan G. W., Todd A. D., Thompson R., Tunnicliffe Wilson G., Welham S. J., White R. P.. Genstat 5, Release 3, Reference Manual. Oxford; Clarendon Press (1993)
• 45 Raijmann L. E. L., van Leeuwen N. C., Kersten R., Oostermeijer J. G. B., den Nijs H. C. M., Menken S. B. J.. Genetic variation and outcrossing rate in relation to population size in Gentiana pneumonanthe L.  Conservation Biology. (1994);  8 1014-1026
• 46 Robertson H. J.. A life history approach to the study of plant species rarity: Gentianopsis crinita in New York state. PhD thesis, Cornell University, Ithaca, New York. (1992)
• 47 Schmidt K., Jensen K.. Genetic structure and AFLP variation of remnant populations in the rare plant Pedicularis palustris (Scrophulariaceae) and its relation to population size and reproductive components.  American Journal of Botany. (2000);  87 678-689
• 48 Studer S.. The influence of management on the floristic composition of hay madows. PhD thesis, Swiss Federal Institute of Technology (ETH), Zürich. (2000)
• 49 Urbisz A., Urbisz A.. Protected plants on south-western part of Silesian Upland. Prace Naukowe Uniwersytetu Slaskiego w Katowicach 0 (1761) (1998): 113-142
• 50 van der Meijden R., Odé B., Groen C. L. G., Witte J. P. M., Bal D.. Bedreigte en kwetsbare vaatplanten in Nederland. Basisrapport met voorstel van de Rode Lijst.  Gorteria. (2000);  26 85-208
• 51 van Treuren R., Bijlsma R., Ouborg N. J., van Delden W.. The significance of genetic erosion in the process of extinction. III. Inbreeding depression and heterosis effects caused by selfing and outcrossing in Scabiosa columbaria. .  Evolution. (1993);  47 1669-1680
• 52 Welten M., Sutter R.. Verbreitungsatlas der Farn- und Blütenpflanzen der Schweiz. Basel; Birkhäuser Verlag (1982)
• 53 Widén B.. Demographic and genetic effects on reproduction as related to population size in a rare, perennial herb, Senecio integrifolius (Asteraceae).  Biological Journal of the Linnean Society. (1993);  50 179-195
• 54 Young A., Boyle T., Brown T.. The population genetic consequences of habitat fragmentation for plants.  Trends in Ecology and Evolution. (1996);  11 413-418

Editor: F. R. Scarano