UK summers getting wetter and soils less acidic, data finds

Changes in weather, atmospheric deposition, vegetation, invertebrates and soils were found at ECN sites
Changes in weather, atmospheric deposition, vegetation, invertebrates and soils were found at ECN sites

Changes in air pollution and weather patterns have had marked effects on the UK’s terrestrial environment over the past 20 years.

This is the main conclusion drawn from assessments of data from several of the UK’s longest running environmental research sites that comprise the UK Environmental Change Network (or ECN), presented in a new Special Issue of the journal Ecological Indicators.

Summers are getting wetter, soils are less acidic and plant species richness is increasing, according to long-term environmental studies at ECN sites.

The special issues includes papers on changes in weather, atmospheric deposition, vegetation, invertebrates and soils at ECN sites.

While UK air temperatures have risen significantly since the onset of industrialisation (in line with the expected consequences of global warming), air temperatures at ECN sites showed little net change over the specific 1993-2012 period studied.

Increase in summer rainfall

Nevertheless nearly all of the twelve ECN sites experienced marked increases in the amount of summer rainfall, while the frequency and intensity of rainfall also increased.

The effect of large recent reductions in acidic emissions from power stations and heavy industry can be seen in substantial reductions in the atmospheric deposition of sulphur and acidity to all ECN sites.

This in turn has stimulated a gradual but widespread reduction in the acidity of non-agricultural soils.

Conversely, atmospheric concentrations of ammonia, that is produced primarily from agricultural sources and can have an undesirable fertilising effect on sensitive plant species, showed relatively little change across the network over the monitoring period.

Surprisingly, the number of plant species occurring within a given area (plant species richness) increased across a range of different habitats.

Reductions in soil acidity

These changes were most clearly linked to reductions in soil acidity, although species with a preference for wetter soils increased in some drier lowland locations, while reductions in the use of fertilisers were also likely to have contributed to the overall pattern in more agricultural situations.

This Special Issue marks the first twenty years of monitoring at terrestrial ECN sites where measurements of weather, air quality, soil and water chemistry and a range of plants and animals are made in close proximity using standard monitoring methods by a consortium of the UK’s environmental research institutes and agencies.

Compiled by guest editors Andrew Sier and Don Monteith of the NERC Centre for Ecology & Hydrology, the collection of papers illustrates the diverse ways in which ECN’s long-term environmental monitoring and associated research helps to identify and quantify the causes and consequences of environmental change across a broad range of UK habitats.

In addition to detailing changes in weather, air pollution and plant communities at the sites, studies also include investigations into responses of plant, butterfly, moth and ground (carabid) beetle communities to changes in the environment driven by changing weather patterns (e.g. summer temperatures and drought events) and local management.