Title: Effect of Salix phylicifolia patches on microsite availability on degraded sites in Iceland

Within any degraded sites are “islands of fertility” that differ in environmental characteristics on the spatial scale of the individual seed or seedling. By studying conditions at these microsites we can learn about the barriers to restoration and also use the microsites to kickstart the process of restoration. This study assesses the presence of microsites created by “tea leaved” willow a native shrub in Iceland. This study seeks to answer the questions whether “tea leaved” willow (Salix phylicifoli) improves microsites for colonization and succession in degraded sites, if the effect of the patch extends beyond the patch canopy and whether the microsite is a result of biological processes or a physical process due to capture of organic debris, aeolian material and snow by the willow canopy. The study also assesses if the presence of willow patches leads to variation in plant composition and reduced susceptibility to erosion. Soil samples were taken in and around willow patches of differing canopy diameter and analysed for total carbon, phosphorus, nitrogen, pH and water holding capacity. These samples were compared to a control sample taken in an area without any willows. The willow site was also compared to another site without willows to assess resistance to wind and water erosion which are major drivers of degradation in Iceland. The results show that the presence of willows improved soil quality, as seen in higher values of total C, N, and P. The presence of willows also ameliorates soil pH which could benefit plants that thrive in low pH soils. Willows ultimately increased foliar cover and improved site stability to soil erosion by both water and wind. It is concluded that willows can be used for land restoration as a low cost alternative to seeding and fertilizer application.