The fauna of Europe is all the animals living in Europe and its surrounding seas and islands. Europe is the western part of the Palearctic realm (which in turn is part of the Holarctic). Lying within the temperate region, (north of the equator) the wildlife is not as rich as in the hottest regions, but is nevertheless diverse due to the variety of habitats and the faunal richness of Eurasia as a whole.
Before the arrival of humans European fauna was more diverse and widespread than today. The European megafauna of today is much reduced from its former numbers. The Holocene extinction drastically reduced numbers and distribution of megafauna and continues to (such as with wolves and bears). Many of these species still exist in smaller numbers, while others thrive in the developed continent free from natural predators, with the former threatened by human activity (particularly megafaunal species).
The formation of the European fauna began in the Mesozoic with the splitting of the Laurasian supercontinent and was eventually separated from both North America and Asia in the Eocene. During the early Cenozoic, the continents approached their present configuration, Europe experienced periods of land connection to North America via Greenland, resulting in colonization by North American animals. In these times, higher sea levels sometimes fragmented Europe into island subcontinents. As time passed, sea levels fell, with seas retreating from the plains of western Russia, establishing the modern connection to Asia (Priabonian). Asian animal species then colonized Europe in large numbers, and many endemic European lineages (e.g. primates) died out ("grande coupure").
The cyclic changes of the Pleistocene between cold and warm periods resulted in antagonistic responses within two different groups of organisms: one expanding during the warm periods and retracting during the cold phases and another with opposed responses (the latter group is composed of so-called arctic and alpine species).[1]
Glaciation during the most recent ice age and the presence of man affected the distribution of European fauna. As for the animals, in many parts of Europe most large animals and top predator species have been hunted to extinction. The woolly mammoth was extinct before the end of the Neolithic period. Tree species spread outward from refugia during interglacial periods, but in varied patterns, with different trees dominating in different periods.[2] Insects, on the other hand, shifted their ranges with the climate, maintaining consistency in species for the most part throughout the period (Coope 1994). Their high degree of mobility allowed them to move as the glaciers advanced or retreated, maintaining a constant habitat despite the climatic oscillations. Mammals recolonized at varying rates. Brown bears, for instance, moved quickly from refugia with the receding glaciers, becoming one of the first large mammals to recolonize the land.[3] The last glacial period ended about 10,000 years ago, resulting in the present distribution of ecoregions.
The north-eastern Atlantic Ocean may be divided into two main biogeographic regions - the Lusitanian (west of British Isles, Bay of Biscay, Iberian coast as far as Gibraltar), and northern European seas (including North Sea and Baltic Sea).[4] A clearly distinct area is also the Macaronesian Biogeographic Region.