Circumpolar diversity of spiders: implication for conservation and management

Yuri M. Marusik  

Spiders (Araneae) are one of the best objects for studying and monitoring species diversity in terrestrial ecosystems, especially at high latitudes, because of their 1) abundance in all types of biotopes, 2) high or highest species diversity (within arctic macroarthropods) and 3) easy collecting methods. During last two decades, number of taxonomic and faunistic publications dealing with arctic and subarctic spiders, both in
the Palaearctic and Nearctic regions, has increased markedly. The previously almost or entirely unknown faunas of Polar Ural, Krasnoyarsk Province, Yakutia, NE Siberia, Tuva, Yukon Territory (and British Columbia, Manitoba and Quebec) are now well-known due to several recent catalogues and check-lists. More than 300 spider species have been described from arctic and boreal zones of Asia during last 15 years. Such an increase of information makes possible to analyze the basic pattern of spider diversity in northern Holarctic and to make suggestions for conservation.

Up to now there are still some areas in Eurasia which could be regarded as unstudied "white spots" and therefore investigations of terrestrial arthropods are required in West Siberia (from Ob to Yenisei), NW Yakutia (from Kotui to Olenyok), and in northern parts of the Verkhoyanski and Cherski Mountain ranges.

While number of species found in faunas north of 60°N varies from 620 (Finland) to 300 (Yukon Territory), species lists of each fauna allow to show the most interesting and important areas of species diversity. Only two areas, divided by the Bering Strait, namely NE Siberia and NW North America have marked proportion of endemic taxa (around 8 %) belonging to several spider families. Such a level of endemism has been found also in some groups of insects: among row beetles (Staphylinidae) 11 % of species are endemic in NE Asia. The proportion of endemics is no more than 1 % in any other area north of 55°N.

High level of endemism, together with rather high known species diversity in NE Siberia (550 spider species) and NW Nearctic (about 500 species) and inadequate level of investigation in these areas shows high necessity of further studies and of
creation of a net of protected areas at least in NE Siberia, where there are only a few reserves.