A Framework Model for Current Land Condition in Iceland.

Iceland border the Arctic with cold maritime climate and a large proportion of the land placed at highland plateaus. About 1100 years of human disturbance, such as grazing and wood harvesting, has left much of the island's ecosystems in a poor state, ranging from barren deserts to areas with altered vegetative composition and degraded soils. We constructed a novel resilience-based model (RBC-model) for current land condition in Iceland to test which and how factors, including elevation, slope characteristics, drainage, and proximity to volcanic activity, influence the resilience and stability of ecosystems to human disturbances. We tested the model by randomly placing 500 sample areas (250 x 250 m) all over the country and obtaining values for each factor and current land conditions for each area from existing databases and satellite images. Elevation and drainage explained the largest portions of variability in land condition in Iceland, while both proximity to volcanic activity and the presence of scree slopes also yielded significant relationships. Overall, the model explained about 65% of the variability. The model was improved (R2 from 0.65 to 0.68) when the country was divided into four broadly defined regions. Land condition at the colder northern peninsulas was poorer at lower elevations compared to inland positions. This novel RBC model was successful in explaining differences in present land condition in Iceland. The results have implication for current land use management, especially grazing, suggesting that management should consider elevation, drainage, slopes and location within the country in addition to current land condition.