A variety of threats are impacting mammal in Europe. To better understand the leading threats to mammals, researchers recorded known threats to each mammal species using a standardised list (IUCN Major Threat Authority File) of major threats. A summary of the number of species affected by each threatening process is shown below.
Habitat loss and degradation have by far the largest impact on both threatened and nonthreatened terrestrial species, affecting 27 of the 29 threatened species, and 94 species in total. The number of species impacted by habitat loss and degradation is nearly three times greater than the next most common threat, pollution (including global climate change). Human disturbance, accidental mortality (e.g. bycatch or vehicle collisions), invasive alien species and overharvesting were also identified as significant threats to terrestrial mammals in Europe.
The two most frequently recorded major threats to marine species were accidental mortality (e.g. entanglement in fishing gear and ship strikes) and pollution. These threats are particularly severe in the enclosed seas of the continent such as the Mediterranean, the Black Sea, and the Baltic. Although harvesting (e.g. overexploitation through unregulated commercial whaling) only ranked third overall when looking at both threatened and nonthreatened species, it was shown to be a highly significant threat for threatened species. All Vulnerable, Endangered, Critically Endangered, and Regionally Extinct species had harvesting listed as a major threat. For a number of these species, historic overexploitation is the main reason why they are currently listed as threatened; some species have failed to recover even though their harvest has now ceased.