Mound-building Formica ants (MBF; ants of the genus Formica excluding those from the subgenus Serviformica) are a group of keystone species widespread in temperate and boreal forests and natural grasslands. They provide important ecosystem services, especially in forest habitats, and their large and long-lived nests are habitat to a broad range of other species, so-called myrmecophiles. While there is increasing evidence of local declines and extinctions due to fragmentation of their forest habitats, climate change, changing management practices, or conversion of natural grasslands to more intensively used agricultural land, an assessment of population trends and threat status of these ants across European countries is largely lacking. This is mainly due to the lack of a common monitoring strategy but also due to differences in conservation status throughout the EU. In addition, it is unknown how the multitude of taxa that depend on the peculiar microhabitat of Formica nest mounds are impacted by the above mentioned threats to MBFs. Therefore, an international, coordinated framework is needed to develop a common cost-effective and efficient monitoring strategy of MBFs and their associated invertebrate (and vertebrate) communities, allowing a comparison of population trends across Europe.

Within the project MonitAnt we will compare existing monitoring strategies of Citizen Science projects and other monitoring programmes. By compiling the available data, we will be able to inform stakeholders on the current status of MBFs on a transnational level. Within MonitAnt the newly developed monitoring strategy will be validated including different forest and grassland types (in terms of management and along large latitudinal and altitudinal gradients) and potentially refined in the field. This validation phase will be used to collect baseline data on the diverse invertebrate species hosted by these umbrella species, on their importance in the diet of protected vertebrates, as well as to characterize threshold patch sizes for survival and reproduction, to help close current knowledge gaps. MonitAnt aims to deliver a harmonized efficient and cost-effective monitoring strategy that will be made freely available to stakeholders in policy making and also for citizen science projects with the aim that long-term monitoring of population trends of mound-building Formica ants (MBF) and their associated myrmecophiles is enabled.