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Moths and their use as sensitive environmental indicators

Moths are a diverse group of organisms, with 2600 species occurring in the UK.  Of these around 50% of the national total are to be found in our region.  This wide range of species has a vast range of different ecological requirements, largely determined by their preference for particular larval (caterpillar) foodplants.  Some species are also highly sensitive to erratic fluctuations in weather, while others adapt more readily.  Moths are therefore an excellent and sensitive indicator, both of environmental quality and change, and over time, of climatic change.

Moths are generally thought of as nocturnal. While this is substantially true, a minority of species, around 10% of our locally occurring species are exclusively diurnal.  Carrying out diurnal and nocturnal survey, while significant for an absolute site species inventory increases cost, so substantial indicative knowledge can be obtained by focusing on the nocturnal element.

Buff-tip

Nocturnal moth survey is essentially conducted using UV lights, to which moths are attracted. They are easy to attract to low energy actinic traps operated from a 12 V car battery or similar.  This type to trap is safe to leave unattended, is placed in the habitat to survey at dusk, is left operating overnight and the assembled moths, which remain torpid and resting in the trap, are then recorded in the first hours of light during the following morning and released where they were found.

Carrying out a study in the way described augments the likely species inventory of a site and gives the greatest amount of information about habitat quality of that site.  It is also of great value to continue such work into successive years since continuing over a longer period also allows changes in species diversity to be seen, e.g., species that decline or arrive due to ongoing changes that are taking places in the general environment and showing effect of climate change locally.

INCA has staff with considerable experience in this field so fully understands the local and national context.  We compile annual reports detailing the species observed, including accounts of those that are of regional, or even national, significance.  This work, if carried out over a succession of years forms a core part of any site biodiversity action plan, in addition to other key fauna and flora on the site.  So, if you are interested in joining the six members that have carried out such work on their sites, including training members of your own staff to be able to contribute towards surveying this group of important environmental indicators, then contact us and we will be delighted to help.