 |
| Titel |
Plant colonization, succession and ecosystem development on Surtsey with reference to neighbouring islands |
| VerfasserIn |
B. Magnusson, S. H. Magnússon, E. Ólafsson, B. D. Sigurdsson |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 19 ; Nr. 11, no. 19 (2014-10-09), S.5521-5537 |
| Datensatznummer |
250117632
|
| Publikation (Nr.) |
 copernicus.org/bg-11-5521-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| Plant colonization and succession on the volcanic island of Surtsey, formed in 1963,
have been closely followed. In 2013, a total of 69 vascular plant species had
been discovered on the island; of these, 59 were present and 39 had
established viable populations. Surtsey had more than twice the species of
any of the comparable neighbouring islands, and all of their common species had
established on Surtsey. The first colonizers were dispersed by sea, but, after
1985, bird dispersal became the principal pathway with the formation of a
seagull colony on the island and consequent site amelioration. This allowed
wind-dispersed species to establish after 1990. Since 2007, there has been a
net loss of species on the island. A study of plant succession, soil
formation and invertebrate communities in permanent plots on Surtsey and on
two older neighbouring islands (plants and soil) has revealed that seabirds,
through their transfer of nutrients from sea to land, are major drivers of
development of these ecosystems. In the area impacted by seagulls, dense
grassland swards have developed and plant cover, species richness, diversity,
plant biomass and soil carbon become significantly higher than in low-impact
areas, which remained relatively barren. A similar difference was found for
the invertebrate fauna. After 2000, the vegetation of the oldest part of the
seagull colony became increasingly dominated by long-lived, rhizomatous
grasses (Festuca, Poa, Leymus) with a decline in species richness
and diversity. Old grasslands of the neighbouring islands Elliđaey
(puffin colony, high nutrient input) and Heimaey (no seabirds, low nutrient
input) contrasted sharply. The puffin grassland of Elliđaey was very
dense and species-poor. It was dominated by Festuca and
Poa, and very similar to the seagull grassland developing on Surtsey. The Heimaey
grassland was significantly higher in species richness and diversity, and had
a more even cover of dominants (Festuca/Agrostis/Ranunculus). We
forecast that, with continued erosion of Surtsey, loss of habitats and
increasing impact from seabirds a lush, species-poor grassland will develop
and persist, as on the old neighbouring islands. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|