The atlas survey that took place during the six years from 2000 to 2005 produced the first detailed maps of the distribution of dragonflies and damselflies in Hertfordshire.
Large Red Damselfly, (Pyrrhosoma nymphula) @ Tom Speller
Since then several new species have reached the county, with most of these now likely to be breeding residents, including some that are now either widespread or showing signs of increasing their distribution in Hertfordshire.
This intention of the current survey will be to collect data necessary for the following:
- Map the current distribution of all dragonfly and damselfly species in the county. The intention will be to cover every tetrad (2 x 2 km square) in the county as a minimum, but records are requested to be submitted by 1 km square, or with more precise locations
- Establish the breeding status of each species at as many sites as possible. Dragonflies and damselflies are capable of travelling large distances and may be recorded well away from sites where they are actually breeding. Knowing where different species are successfully breeding is very important for their conservation, so observers are asked to report breeding evidence if they are able to.
- Record flight periods. There is evidence that the flight periods of dragonfly and damselfly species in the UK are changing as a result of climate change. Flight periods can be plotted based on the number of records of adults of each species received during each summer. The more records there are for a species, the more accurately flight periods can be shown.
- Investigate habitat preferences. Some species will be found in a wide variety of different habitats, while others tend to be have more restrictive habitat preferences. Records that are given an accurate six number, or even eight number, Ordnance Survey grid reference, or for which habitat details are provided, will help to provide an indication of the type of habitat preferences different species have in the county
- Gain an approximation of abundance population sizes of most invertebrate species are very difficult to assess, and with many dragonfly and damselfly species the number of adults seen flying may not be a good indication of the population present in any particular tetrad. Despite this, we want observers to provide an indication of the number of adults they are finding if they are willing to do so.
The data collected will enable comparisons to be made with past and present distributions of the different species in Hertfordshire. It may also help to identify sites and species that are priorities for dragonfly and damselfly conservation in the county.