Invertebrates are generally inconspicuous but they dominate biodiversity in Wales, as elsewhere. In Welsh terrestrial and freshwater environments there are probably more than 20,000 different species of macro-invertebrates and, as an example of their abundance, it has been estimated that there are more spiders in a three-hectare field than there are sheep in Wales. Invertebrates occupy all possible habitats from crevices in inter-tidal rocks to scree on the summits of our mountain tops, from birds’ nests to saturated moss at the edge of waterfalls. This extraordinary diversity is possible because of the specialised niches that many species inhabit as a result of their adaptations to specific environmental conditions. They are also crucially important to the health of ecosystems. From the earthworms that aerate our soil, to the bees that pollinate our crops, the woodlice that break down decaying plant material, the mussels that filter our river water, and the ladybirds that eat pest aphids, we rely on invertebrates for the basic resources we depend upon.
Top image shows Cicindela maritima (dune tiger beetle) - a scarce inhabitant of foredunes in England and Wales, with several Welsh sites including Morfa Dyffryn and Whiteford supporting strong populations.
Bottom image shows Odontomyia hydroleon (Barred Green Colonel) - a rare soldier fly occurring in only two sites in the UK. The base-rich flushes at Banc y Mwldan SSSI in Ceredigion is the only location in Wales for this species.
Image © NRW /MJ Hammett)