||Variation of sexual and clonal reproduction in the alpine Geum reptans in contrasting altitudes and successional stages|
||Tina Weppler, Jürg Stöcklin|
||Basic and Applied Ecology 6: 305-316|
We studied the relative frequency of sexual vs. clonal reproduction in 20 populations of the alpine pioneer plant Geum reptans due to altitude (low and high) and succession (early and late). Additionally, the frequency of life-cycle stages, the frequency of reproducing adults, seed size, and seed number per flower head were determined. With increasing plant size, the probability of producing flower heads and stolons simultaneously increased (P < 0.001). Individuals of all sizes tended to produce more flower heads than stolons. Stolon production was more frequent only if plants reproduced by one reproductive mode (P < 0.05). The significant difference among populations in the frequency of clonal reproduction and of seed number per flower head was not explained by contrasting habitats. However, clonal reproduction increased in populations at low and high altitude compared to populations at intermediate altitude (P < 0.05), partly in accordance with the expectation that clonal reproduction increases with altitude. High altitude populations were characterised by fewer juvenile and small plants and an increase in the frequency of reproducing adults. This indicates not only lower recruitment but also, that after successful establishment, growth and reproduction in Geum reptans is not generally restricted, even above 2850 m. Our results suggest that variation in the frequency of sexual and clonal reproduction in G. reptans is probably more shaped by individual, i.e. plastic responses to local environmental conditions than by adaptation to environmental gradients.
clonal growth · glacier foreland · pioneer plant · plasticity · stolons · succession · trade-off
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