Research from the UK has revealed declines in populations and diversity of ground beetles.

Researchers from Rothamsted Research Institute and the Centre for Ecology and Hydrology, working as part of the Environmental Change Network, discovered "significant" declines in carabid beetle biodiversity during their UK study; the research, published in the Journal of Applied Ecology revealed an overall large decline in beetle diversity.

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However, although beetle biodiversity has fallen across the UK as a whole, the losses varied from region to region and between different habitats. The authors said this provide some hope for the arthropods; suggesting that there is potential for localised land management to "offset the adverse effects of wider scale environmental change."

The scientists monitored beetle populations at a national scale, looking at 11 sites over fifteen years. They found that beetle species declined by around 30 per cent over the studied period, but warned that regional variation masked some of the most concerning trends, including declines of over 50 per cent in some regions. They said the declines reported in beetle species "are comparable to those reported for butterflies and moths and increase the evidence base showing that insects are undergoing serious and widespread biodiversity losses."

Declines were most severe on mountains, in upland moorland in the north and in pasture in the west. Conversely, populations remained stable in woodland and hedgerows, and increased at a downland site. Studies into agroecology, a sustainable agriculture method which integrates trees into the farmed environment, providing benefits for farmers and the environment, and which is being seriously studied in France in particular, have shown the methods various applications can benefit a variety of insect life.

Research from the UK in the late 1990s showed that many arthropod species (the phylum to which beetles belong) flourished in agroforestry systems. Scientists at Cranfield university found "the number of individuals and the number of airborne arthropod species within an agroforestry system (both in the hedge and the arable alley) were greater than in an arable control." However, their results proved more varied for ground beetles.

Rothamsted spokesperson David Brooks said of the findings, "Carabid beetles contribute to the viability and health of ecosystems. They are particularly important in agriculture because they help control pests and weeds. These rather alarming trends in carabid beetle decline do contribute to growing evidence that insects are undergoing serious biodiversity losses."

The authors have called for further research into management methods which could support the beetles, and wider insect populations, and how these techniques can "offset adverse, wider-scale changes in climate or the environment." Although the Rothamsted researchers suggested climatic and environmental changes are affecting the beetles, particular concerns have been raised about the disappearance of trees from the countryside and effects of increased use of agricultural chemicals on other insect populations. Brooks commented "In particular, retaining woodland and hedgerows in the landscape, and managing them in appropriate ways, may help to conserve beetles."

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