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- Marteinsdottir, Bryndis, et al.
(författare)
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An experimental test of the relationship between small scale topography and seedling establishment in primary succession
- 2013
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Ingår i: Plant Ecology. - : Springer Science and Business Media LLC. - 1385-0237 .- 1573-5052. ; 214:8, s. 1007-1015
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Tidskriftsartikel (refereegranskat)abstract
- In infertile environments, the spatial scale and distribution of favourable microsites may be an important determinant of vegetation patterns. Such patterns may be persistent although the association and causality may only be detectable during initial establishment. In this study we investigated experimentally how spatial variation on two different scales and species-specific traits affected seedling survival at an early successional site on SkeiA degrees ararsandur, a 1,000 km(2) homogeneous glacial outwash plain in SE-Iceland. Seedlings of eight native species were transplanted into six different micro-topographical combinations: three types of microsites (lee side of small stones and cushion plants, and control), located within two topographical features (shallow depressions and surrounding flats). Seedling survival was then recorded. Only 11 % of transplanted seedlings survived through the second winter, however seedlings that survived past the second growing season were likely to persist. Survival rates varied by species and were positively linked to seed size. Seedling survival was only weakly associated with spatial variation. The strongest association found was that survival was sometimes higher on flats compared to depressions. Sand accumulation in depressions might lower seedling survival there. We conclude that early plant establishment at the site, and the emergent vegetation mosaic, is most likely produced by the interaction of stochastic factors, such as the sand storms that intermittently rage across the plain and species-specific properties like seed size. However, in better-vegetated areas of SkeiA degrees ararsandur depressions often have higher moss and vascular plant cover than nearby flats, suggesting that moss may control vegetation patterns seen later in succession.
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| 2. |
- Marteinsdottir, Bryndis, et al.
(författare)
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Development of vegetation patterns in early primary succession
- 2010
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Ingår i: Journal of Vegetation Science. - : Wiley. - 1100-9233 .- 1654-1103. ; 21:3, s. 531-540
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Tidskriftsartikel (refereegranskat)abstract
- Question We investigated colonisation filters in early plant community development on a glacial outwash plain. We asked if these were related to seed limitation or to a lack of safe sites, if topographical heterogeneity affected species patchiness and how species life cycles influence successional trajectories. Location An outwash plain (Skeithararsandur) in southeast Iceland. Methods We identified surface heterogeneity at two different scales, ca. 10-15 cm (larger stones and established plants) and ca. 50 m (shallow depressions representing dry river beds) at two study sites. We quantified species cover, flowering plant density, seed production, seed rain, seed bank density, seedling emergence and seedling survival from June 2005 to June 2007 for the whole plant community, and measured seed production for five species. Results Mean vegetation cover was < 2.5% at the sites. Low emergence rates and high seedling mortality were the two main recruitment filters. Only 1.4% of seedlings emerging in 2005 survived into the 2007 growing season. Topographical heterogeneity had little effect on plant colonisation. High annual variation was recorded, and the two study sites (ca. 2 km apart) differed in their colonisation success. Of the five species, establishment of Cerastium alpinum and Silene uniflora was most limited by lack of seeds, whereas establishment of Luzula spicata, Poa glauca and Rumex acetosella was most limited by safe sites. Conclusions We conclude that colonisation processes and patterns in early primary succession on Skeithararsandur were largely influenced by stochastic factors.
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