Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2019

Erindi/veggspjald / Talk/poster V16

Plant functional group abundance in Iceland’s highlands, 300-1950 CE: effects of abiotic factors, grazing and biotic interactions.

Höfundar / Authors: Ölvir Styrmisson (1), Sigrún Dögg Eddudóttir (2), Guðrún Gísladóttir (1) & Egill Erlendsson (1)

Starfsvettvangur / Affiliations: 1. University of Iceland, 2. Uppsala University

Kynnir / Presenter: Ölvir Styrmisson

Both abiotic factors and land use are important for vegetation changes in Iceland’s highlands. Plant interactions can also shape these changes. Here we examine the effects of these factors on plant functional groups in the understudied highlands during the last two millennia. Using two highland peat cores, pollen and spore accumulation rates (PAR/SAR) were found via pollen analysis and age-depth models. Shrub PAR was modelled with General linear models and Generalized Linear Autoregressive Moving Average Models. Proxies for the factors used came from these cores, a nearby lake sediment core and sourced data. Evergreen shrubs, forbs and grasses increased in abundance while little long-term change was seen for deciduous shrubs, sedges and pterophytes. Grazing negatively affected deciduous shrubs and sedges. Erosion affected grasses negatively and pterophytes positively. Soil organic content affected deciduous shrubs and most forbs positively and grasses negatively. Tephra deposition positively affected most forbs. Effects of annual temperature changes weren’t observed. Deciduous shrubs and sedges negatively affected most functional groups and were very important for evergreen shrubs. Deciduous shrubs and sedges may have succeeded grasses and pterophytes respectively. Forbs and grasses may have competed while pterophytes benefited from both. Overall, soil organic content, erosion, grazing, deciduous shrubs and sedges were the most important for the groups’ abundance.