Small land use changes reap big freshwater benefits
The UK landscape is a mosaic primarily of agriculture interspersed with woodland, grassland, urban enclaves and veined with river networks and wetlands. We should all realise by now that this pattern in the landscape has a marked effect on ‘ecosystem goods and services’, the natural benefits that the environment provides to us, and particularly those associated with freshwater. How we use (or abuse) the land, i.e. influence the landscape pattern, and the downstream consequences to water quality are a focus of the current consultation on diffuse pollution to which WTT has already responded (and I encourage you to do so too).
A new study of an urbanising but predominantly agricultural landscape in the US draws upon data from 100 Wisconsin sub-watersheds and has important implications for managing and restoring landscapes to enhance surface water quality, groundwater quality, and groundwater supply. The study considered the landscape pattern in terms of composition (the type and amount of particular patches) and its configuration (the layout of those patches); and while both appear to have some bearing upon freshwater services, the composition had a stronger influence on water quality and supply.
In other words, tweaking the relative size of some of those patches in the pattern could bring about considerable benefits to freshwaters. This is especially important when considering that large-scale changes to the landscape will rarely happen. One of the small tweaks with a disproportionate benefit would be to increase the size of wetlands and buffer strips within the landscape, native vegetation placed between cropland and lakes and rivers, with the multiple benefits of providing shade, bank-stability, litter and shelter, whilst taking up nutrients and trapping soils (reducing erosion) from the land. To many recipients of WTT Advisory Visits, this should sound very familiar! Compare and contrast the river banks in the image here: on the far bank there is a fence and (narrow) buffer strip; on the near bank, there is no protection and the erosion is evident. A picture paints a thousand words, but do we necessarily take heed?
In essence, the study above is landscape scale support for some of the very small scale mitigation measures advocated, for example, by my colleagues at the Lancaster Environment Centre (and in collaboration with the Game & Wildlife Conservation Trust). In a report card for the European Commission, they summarise some of their published findings on how small artificial wetlands created in the corners of agricultural land can prevent soil loss and recapture agricultural by-products, thereby reducing pollution of nearby watercourses. Simple, but oh so effective. WTT Conservation Officers spent a very interesting day at the site of this work, Loddington in Leicestershire, earlier in the year.