During research conducted in northern Italy for the State Forestry Service LIFE Nature project, a single male specimen of the scolytine ambrosia beetle Monarthrum mali (Fitch) was collected in an ethanol-baited window Xight trap. Trapping started in 2005, but the species was Wrst collected in August 2007, suggesting that the establishment of M. mali in northern Italy is very recent.Monarthrum mali represents the second North American ambrosia beetle to be introduced to Europe, and joins Phloeotribus limnaris and Xylosandrus crassiusculus as recent scolytine introductions to Europe via Italy that pose potential threats to Europe's nurseries, orchards and plantations.

Bark and ambrosia beetles (Coleoptera, Scolytinae) are amongst the most important wood-boring insects introduced to Europe. During field investigations conducted between 2019 and 2021 in different countries and regions of Europe, many exotic species have been recorded providing new and relevant data. Dryoxylon onoharaense (Murayama, 1933) is recorded in Europe for the first time. Xyleborinus attenuatus (Blandford, 1894) is a species new to Italy, while Xylosandrus germanus (Blandford, 1894), Hypothenemus eruditus (Westwood, 1836) and Amasa sp. near A. truncata are new country records for Portugal. Cnestus mutilatus (Blandford, 1894), Phloeotribus liminaris (Harris, 1852) were collected in Italy and Amasa sp. near A. truncata was collected in France after the first discovery, confirming their establishment and their dispersal into new areas.

This research is a contribution to an integrated overview of the alpine low-order river ecosystem. We associated the results obtained from colonization and breakdown processes (functional aspects, i.e. colonization of natural and artificial leaf packs and of artificial inorganic substrates), with the morphohydrological features of the river bed, with density and biomass of benthic invertebrates and with banks quality. We studied the Ausor stream, North-East Italy, a natural alpine stream with a narrow steep gradient channel.The applied monitoring methods allowed us to point out the total biodiversity, the seasonal and regional heterogeneity of macrobenthos and of habitats and the efficiency of breakdown and colonization processes. The integrated overview, achieved from the comparison of results, showed that diversity and variability of habitats are connected with the natural morphological development of the river bed and of riparian areas. Furthermore, heterogeneity and variability of habitats are essential in supporting biodiversity and the functional processes occurring in a natural environment.