We present a topographically-derived vegetation model (TVM) that predicts t
he landscape patterns of arctic vegetation types in the foothills of the Br
ooks Range in northern Alaska. In the Arctic there is a strong relationship
between water and plant structure and function and TVM is based on the rel
ationships between vegetation types and slope (tan beta) and discharge (del
ta), two independent variables that can be easily derived from digital terr
ain data. Both slope and discharge relate to hydrological similarity within
a landscape: slope determines the gravitational hydrological gradient and
hence influences flow velocity, whereas discharge patterns are computed bas
ed on upslope area and quantify lateral flow amount. TVM was developed and
parameterized based on vegetation data from a small 2.2 km(2) watershed and
its application was tested in a larger 22 km(2) region. For the watershed,
TVM performed quite well, having a high spatial resolution and a goodness-
of-fit ranging from 71-78%, depending on the functions used. For the larger
region, the strength of the vegetation types predictions drops somewhat to
between 56-59%. We discuss the various sources of error and limitations of
the model for purposes of extrapolation.