Abstract
Climate and land cover are two major factors affecting the
water fluxes and balance across spatiotemporal scales. These two factors
and their impacts on hydrology are often interlinked. The quantification
and differentiation of such impacts is important for developing
sustainable land and water management strategies. Here, we calibrated the
well-known Hydrus-1D model in a data-rich boreal headwater catchment in
Scotland to assess the role of two dominant vegetation types (shrubs vs.
trees) in regulating the soil water partitioning and balance. We also
applied previously established climate projections for the area and
replaced shrubs with trees to imitate current land use change proposals
in the region, so as to quantify the potential impacts of climate and
land cover changes on soil hydrology. Under tree cover,
evapotranspiration and deep percolation to recharge groundwater was about
44% and 57% of annual precipitation, whilst they were about 10% lower and
9% higher respectively under shrub cover in this humid, low energy
environment. Meanwhile, tree canopies intercepted 39% of annual
precipitation in comparison to 23% by shrubs. Soils with shrub cover
stored more water than tree cover. Land cover change was shown to have
stronger impacts than projected climate change. With a complete
replacement of shrubs with trees under future climate projections at this
site, evapotranspiration is expected to increase by ~39% while
percolation to decrease by 21% relative to the current level, more
pronounced than the modest changes in the two components (<8%) with
climate change only. The impacts would be particularly marked in warm
seasons, which may result in water stress experienced by the vegetation.
The findings provide an important evidence base for adaptive management
strategies of future changes in low-energy humid environments, where
vegetation growth is usually restricted by radiative energy and not water
availability while few studies that quantify soil water partitioning
exist.
Original language | English |
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Pages (from-to) | 520-531 |
Number of pages | 12 |
Journal | Journal of Hydrology |
Volume | 558 |
Early online date | 7 Feb 2018 |
DOIs | |
Publication status | Published - Mar 2018 |
Keywords
- boreal climate change
- land cover change
- climate-vegetation interactions
- water balance
- soil hydrology
- Hydrus-1D