Northerness as a habitat for animals
Barren poorer northern nature limits not only the amount of plant species but also the amount of animal species. Although there is a small amount of species which have distributed only to northern areas (see also endemic species!).
Moths, which are probably the most dependent on their host plants are a very good example. Only fourth of our small moth species are able to live in the northernmost parts of our country and in the altitude of Oulu there is less than half of those moths. The distribution ratio of Apoidea that prefer warmer conditions, is even more steep: in the very north there is only 15% of Apoidea species. Of course there are species that like to live only in north, but the amount is very small only about 10%.
On the other hand there are species that are the most abundant in the north. Good example of that are Plecopterans which we have 44 species here in Finland. Almost 90% of those species live in the fell area, when in the southernmost coast area there are only a bit more than a half of the species of Plecopterans. The distribution of Ephemeroptera is quite similar to the distribution of Plecopterans.
The amount of many small rodents of Lapland - including lemming - changes from year to year and often very fierce. It tells the great meaning of ecological conditions in the extreme limits of distribution of species. In the picture there are the population dynamics of the grey red-backed vole in Lapland. When small rodents are abundant also the amount of bigger vertebrates that eat small rodents increases (for example fox, arctic fox, rough-legged buzzard and snowy owl). Their population dynamics is therefore quite much dependent on the amount of small rodents.
Barren poorer northern nature limits not only the amount of plant species but also the amount of animal species. Although there is a small amount of species which have distributed only to northern areas.
Moths, which are probably the most dependent on their host plants are a very good example. Only fourth of our small moth species are able to live in the northernmost parts of our country and in the altitude of Oulu there is less than half of those moths. The distribution ratio of Apoidea that prefer warmer conditions, is even more steep: in the very north there is only 15% of Apoidea species. Of course there are species that like to live only in north, but the amount is very small only about 10%.
On the other hand there are species that are the most abundant in the north. Good example of that are Plecopterans which we have 44 species here in Finland. Almost 90% of those species live in the fell area, when in the southernmost coast area there are only a bit more than a half of the species of Plecopterans. The distribution of Ephemeroptera is quite similar to the distribution of Plecopterans.
The amount of many small rodents of Lapland - including lemming - changes from year to year and often very fierce. It tells the great meaning of ecological conditions in the extreme limits of distribution of species. In the picture (above) there are the population dynamics of the grey red-backed vole (Clethrionomys rufocanus) in Lapland.
When small rodents are abundant also the amount of bigger vertebrates that eat small rodents increases (for example fox, arctic fox, rough-legged buzzard and snowy owl). Their population dynamics is therefore quite much dependent on the amount of small rodents.
Population dynamics are common in the north among others on the group of fowls.
For example the numbers of capercaillie are diminished in the last decades, and numbers
of willow grouse
in last years.
Nesting capercaillie (Tetrao urogallus) population in Finland is about 700 000 individuals at prent.
Occasionally capercaillies can accumulate to very big flocks (even 500 birds!).
More: winter nutrition of capercaillie!
The population dynamics of autumnal carpet is great, too like the population dynamics of many other northern animals. For example in the end of 1960's and middle of the 80’s the larva of autumnal carpet destroyed thousands of hectares of the birch stands of Lapland. In the summer 2004 the number of larva of autumnal carpet was very high for instance in Kilpisjärvi area.
More information about autumnal carpet:
a) Moth itself
b) The birch damage caused by it
The areas of distribution of many large carnivores have changed in last centuries. For example the bear hunting was common especially in the early 1900s - and the area of bear was confined to the east border of Finland. At the end of last centyry the bear extended fast almost over the country. The wolf instead retreated to the eastern border, but wolwes can occasionally meet up westward, too. Here the similar maps of wolverine!
The seasonal migration of birds can be found from its own section.
Northerness has also been dealt in many ways in parts about ecology.
The section "Animal life, (in general)" ends here!
