HR: 0800h
AN: H51H-0877    [Abstracts]
TI: Green Alder Pattern in Relation to Slope-Area Scaling Regimes of a Headwater Basin in the Eastern Italian Alps
AU: * Tarolli, P
EM: paolo.tarolli@unipd.it
AF: Department of Land and Agroforest Environments, University of Padova, viale dell'Universita' 16, Legnaro, PD 35020, Italy
AB: The landscape of headwater alpine basins is strongly influenced by erosion processes. The scaling relationship between the local slope of a given point on the landscape and its drainage area reveals information about the dominant erosion process over geomorphic time scales. There has been significant research literature which documents how vegetation distribution is coupled with local topography. Understanding the interrelationship between the vegetation, especially between some plant species than others with local topography will help us to better understand how the landscape change due to a specific geomorphic process is related to vegetation change. In this paper a steep Alpine debris flow-landslide dominated headwater catchment with uniform lithology substrata, and vegetation characterized by various grass, shrub, and forest species has been considered. The basin was chosen as study area because it is representative of the lithological and physiographical conditions frequently observed in the Carnia region (Eastern Italian Alps). The work has focused on the analysis of scaling regimes of local slope versus contributing area in relation to each vegetation types with particular attention to the spatial distribution of Alnus viridis, the main shrub species present in the area. Alnus viridis, also known as Green Alder, is an early successional shrub growing up to 4 m that invades screes, landslide scree, avalanche debris on talus slopes, avalanche slide paths and pastures in the subalpine zone of the Alps. It is widespread on moist, north-exposed medium-steep slopes on silicious bedrock at an altitude ranging from 1500 to 2000 m a.s.l.. LiDAR-derived DSM (Digital Surface Model) served as the basis to evaluate the distribution of vegetation canopies. The LiDAR bare-ground elevation points were used for the DTM (Digital Terrain Model) interpolation at the same resolution of the DSM. The results revealed that there is significant relationship between the local slope and drainage area depicting the natural location of Green Alder and other vegetation types. Profound landslide/debris flow topographic signature is detected in areas where Green Alder prevails. Its pioneering ability to colonize the landslide scars and headwater channel hollows, makes it as a key species in the analysis of geomorphic processes at the hillslope/valley transition. The work has broad implications in geomorphology, landscape ecology, landscape evolution with vegetation dynamics for studies in high-altitude extreme-climate Alpine regions.
DE: 0456 Life in extreme environments
DE: 0476 Plant ecology (1851)
DE: 1813 Eco-hydrology
DE: 1824 Geomorphology: general (1625)
DE: 1855 Remote sensing (1640)
SC: Hydrology [H]
MN: 2007 Fall Meeting