Changes in the Natural Water Retention of mountainous landscapes since
the 1820s in the Austrian Alps
Abstract
Interactions of humans with the environment are strongly related to land
use and land cover changes and the available ecosystem services. In last
decades, these changes have led to a degradation of ecosystem services,
including water regulation and flood control. In Alpine areas of
Austria, land cover changes have increased flood risk since the mid of
the 19 th century. In this paper, we assess the
influence of these long-term land use changes on the landscape’s ability
to retain water using the qualitative Water Retention Index (WRI). The
changes are thereby evaluated using the historical (1826-1859) and
present (2016) land cover situation, which is to our knowledge the first
high-resolution and regional application of the WRI. The results show
that the water retention potential mimics the mountainous characteristic
and features. Except for areas strongly dominated by settlement areas,
the highest retention potentials are found in valley floors and the
lowest values are depicted along the Alpine main complex. In low-lying
areas, the retention decreased by over 10 %. It was found that this
decrease can be mostly attributed to settlement expansion. Above 1250 m
land use transformations led to slightly increasing water retention
values owing to the transformation of wasteland or glaciers to stagnant
waters and to the expansion of forest and grassland in high elevations.
This examination allows for a holistic and spatially distributed LULCC
impact assessment on the landscape’s water regulation capacities and
offers valuable high-resolution information for future land use planning
and sustainable land development.