The state of the Dutch larger moth fauna

Moths make up a significant part of the biodiversity both in northwestern Europe and globally. In the Netherlands for instance, 766 species of larger moths are considered native. The interest of amateur recorders in this group in the Netherlands is rapidly growing. This has led to a strong increase in the number of records in the central database, allowing better and more precise calculations on the local trends of moths. About one-third of the species in our analysis are decreasing and could be listed as threatened. On the other hand, some species are strongly increasing. All species together show a significant, declining, trend in abundance. At the same time there exist strong year to year fluctuations in this trend which are due to weather conditions. We conclude, therefore, that the changing climate is having a strong impact on our moth fauna. The absolute number of individuals of the common species has dropped by one-third. We argue that this had a negative impact on plant biodiversity. The need for better protection of moths in northwestern Europe is also implicated by the fact that many species of birds, bats and other groups depend on moths (or their larvae) as main food sources.