Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2021
Erindi/veggspjald / Talk/poster V6
Höfundar / Authors: Vigdís Freyja Helmutsdóttir (1,2), Kristín Svavarsdóttir (2) & Þóra Ellen Þórhallsdóttir (1)
Starfsvettvangur / Affiliations: 1. Institute of Life and Environmental Sciences, University of Iceland, Reykjavík, Iceland, 2. Soil Conservation Service of Iceland, Hella, Iceland.
Kynnir / Presenter: Vigdís Freyja Helmutsdóttir
An ecosystem engineer is a species that causes changes in the biotic or abiotic environment, modulating habitats and resource availability for other species, often in a beneficial way. Shrubs may alter microclimates and their fungal symbionts can modify soil properties. We have examined two ways in which woolly willow (Salix lanata, loðvíðir), a medium-sized deciduous and dioecious shrub and one of Iceland’s most widespread woody species, may act as an ecological engineer. Here we report on its impact on belowground processes and snow accumulation. Two contrasting field sites were selected; the early successional outwash plain Skeiðarársandur (80 m a.s.l.) and the moss-rich willow heath Skaftafellsheiði (380 m a.s.l.). The Tea Bag index was used to measure decay rates and stabilisation of organic soil material along a transect with increasing distances from willow shrubs. Decomposition and stabilisation factors declined with increasing distances from the bushes at both sites, dropping significantly at the rhizosphere margin. Snow accumulation was estimated using temperature loggers placed along the same gradients. Longer and more frequent intervals with consistent values of 0±0.5°C in the close vicinity of willows indicated increased snow retention, protecting the underlying vegetation from harmful freeze-thaw cycles and frost damage. In this way, woolly willow may be considered an engineer of Icelandic ecosystems.