34 research outputs found
An experimental study on the response of blanket bog vegetation and water tables to ditch blocking
We studied the effect of ditch blocking on vegetation composition and water-table depths in a blanket peatland. Measurements were made for a period of four years (water tables) and five years (vegetation) in the inter-ditch areas of three experimental treatments: (i) open ditches, (ii) ditches blocked with closely-spaced dams and (iii) ditches partially infilled with peat and blocked with dams. It is often assumed that ditch blocking will lead to an increase in the abundance of Sphagnum and, potentially, a reduction in the abundance of sedges, particularly the cotton grasses. However, our data show no treatment effects on the abundance of either group. We did find an effect of time, with the abundance of both sedges and Sphagnum spp. varying significantly between some years. For the sedges there was no systematic change over time, while for the Sphagnum spp. abundance tended to increase through the study period. This systematic change was not related to a measure of the vigour of the sedges, although vigour was lower towards the end of the study compared to the beginning. Our vegetation data are consistent with our water-table data. As with plant type abundance, we did not find any statistically significant differences in water-table depths between treatments, both for annual averages and summer averages. We comment on why ditch blocking does not seem to have affected water tables and vegetation composition at our study site
Climate change impacts on groundwater recharge- uncertainty, shortcomings, and the way forward?
An integrated approach to assessing the regional impacts of climate and socio-
economic change on groundwater recharge is described from East Anglia, UK. Many
factors affect future groundwater recharge including changed precipitation and
temperature regimes, coastal flooding, urbanization, woodland establishment, and
changes in cropping and rotations. Important sources of uncertainty and
shortcomings in recharge estimation are discussed in the light of the results.
The uncertainty in, and importance of, socio-economic scenarios in exploring the
consequences of unknown future changes are highlighted. Changes to soil
properties are occurring over a range of time scales, such that the soils of the
future may not have the same infiltration properties as existing soils. The
potential implications involved in assuming unchanging soil properties are
described. To focus on the direct impacts of climate change is to neglect the
potentially important role of policy, societal values and economic processes in
shaping the landscape above aquifers. If the likely consequences of future
changes of groundwater recharge, resulting from both climate and socio-economic
change, are to be assessed, hydrogeologists must increasingly work with
researchers from other disciplines, such as socio-economists, agricultural
modellers and soil scientists