Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2021
Erindi/veggspjald / Talk/poster V10
Höfundar / Authors: Benedikt Traustason (1), Hulda Margrét Birkisdóttir (1), Þóra Ellen Þórhallsdóttir (1), Ólafur Eggertsson (2), Kristín Svavarsdóttir (3)
Starfsvettvangur / Affiliations: 1) Háskóli Íslands, 2) Skógræktin, 3) Landgræðslan
Kynnir / Presenter: Benedikt Traustason
Icelandic mountain birch (Betula pubescens ssp tortuosa) grows on different substrates and has highly variable growth forms, stature, growth rates and reproductive traits. The aim of this project was to gain a better understanding of the structural traits, growth rates and reproduction of the different growth forms. We compared population parameters, measured growth rates and structural variables in three populations in South Iceland that grow in the same regional climate but have contrasting growth forms and are on different substrates. Data were collected at: 1) Núpsstaður (steep southfacing scree slope), 2) Leiðvöllur (moss-covered lavafield) and 3) Skeiðarársandur (early successional outwash plain). To determine growth rate the ring-width index (RWI) was calculated with detrending method using negative exponential model. The ratio between height of the trees and stem length was calculated to describe structural traits. Our preliminary findings showed that the tree height/length ratio for Leiðvöllur (0.72) was significantly lower than Núpsstaður (W=1380, p <0.001) and Skeiðarársandur (W=476, p <0.001). The latter two had similar ratios (0.90 and 0.87 respectively). When comparing RWI between populations we identified a sharp decrease in growth in them all in 2011, which we attribute to tephra fall from the spring eruption in volcano Grímsvötn the same year. All populations showed remarkable recovery the following year.