2.3 Effects of climate change on insects
The global climate has changed significantly during the
20th century. The average global air temperature near the
Earth's surface and oceans rose by 0.74"C between 1906
and 2005 (PCC 2007). At a global level, climate change is predicted to be a key factor affecting future developments
in biodiversity (Hawkins et a|.2003; Rahbek et al.
2007; Beck et al. 2010b| with wide-ranging effects on
forest structure and local spatial distribution patterns
(Sang and Bai 2009). Insect species richness and species
composition are known to be particularly shongly affected
by environmental factors such as temperature and moisture
(Brehm et a|.2003; Axmacher et a|.2009). Global
climate change is accordingly predicted to change the
distribution and therefore also diversity patterns of insect
communities. Many insect species have already observed
to be spreading northwards in the northern hemisphere,
some benefiting from warmer temperatures, e.g. the silverspotted
skipper buttery (Hesperia comma), Roesel's bush
cricket (Metrioptera roeselii), etc, see Thomas et al.
(2001); however, most species have declined in reaction
to climatic change (Masters and Clarke 1998 Asher et al.
2001; Wanen et al.200l).