Odonata - Entomological Society of Latvia - Latvijas Daba

4. DISCUSSION
4.1. THE CHANGES IN DRAGONFLY FAUNA AND DISTRIBUTION IN LATVIA
Changes in the faunistic composition. In the last 20 years in Latvian fauna five new
dragonfly species were found and 12 more could be found in Latvia in the near future. This is
mainly related to the distribution of all southern species found in Europe in northern direction (Ott
2001; Dijkstra 2006; Termaat et al. 2010). The basic distribution areas of the species registered in
Latvia for the first time, except for Aeshna serrata, are found to the south from Latvia (Dijkstra
2006), thus they may be considered southern species. Considering the earlier distribution of these
species (Askew 1988), the continuous research in Latvia and the gradual distribution of species in
northern direction in Europe due to climate change (Termaat et al. 2010), the failure to register the
species before due to their rarity is not likely. A tendency of distribution in northern direction was
also found for several Latvian species. Z. Spuris in his paper on southern elements in Latvia
(Спурис 1951) enlists eight dragonfly species as southern elements of Latvian fauna: Sympecma
paedisca, Lestes virens, Ischnura pumilio, Aeshna mixta, A. isoceles, Anax imperator, Sympetrum
striolatum and S. fonscolombii. This classification was based on the information that at the time of
the development of the paper Latvia was the northern borderline of the distribution areas of these
species. To date, all species mentioned in the paper have registered localities in the northern part of
Latvia and all aforementioned species, except S. fonscolombii, have known localities farther north
from Latvia – in Estonia and Finland (Dijkstra 2006; Martin et al. 2008). When comparing the
historic localities farthest to the north from Latvia (Спурис 1951) and the farthest current localities
in the north, it was found that five species are found 90-140 km and two species are found 30 and
50 km, respectively, farther to the north than before.
In the analysis of the possible habitats, where dragonfly species that potentially may become
a part of Latvian fauna could be found (the stage of the development of the larvae is related to the
specific habitat) according to the latest version of the Habitat Directive (Auniņš 2010) three groups
of habitats and potential species were found.
4. Habitats of sea and brackish places. Target species: L. barbarus, A. serrata.
5. Freshwater habitats.
• Flowing freshwaters. Target species: Coenagrion ornatum, Orthetrum coerulescens.
• Freshwaters of eutrophic lake type. Target species: Lestes viridis, Sympecma fusca,
Erythromma viridulum, Aeshna serrata, Orthetrum albistylum, Crocothemis erythraea.
• Freshwaters of pond type. Target species: Sympecma fusca, Aeshna affinis, Aeshna
serrata, Sympetrum depressiusculum, S. meridionale.
• Small waters (temporal waters, bog pools, pools, shallow depressions). Target species:
Lestes barbarus, Aeshna affinis, Sympetrum depressiusculum.
6. Mire habitats. Target species: Erythromma viridulum, Orthetrum coerulescens (partly),
Sympetrum meridionale.
Providing a prognosis of the changes of dragonfly fauna of Latvia in future it is most likely
that five dragonfly species recorded in the territory of Lithuania – Lestes viridis, Erythromma
viridulum, Aeshna affinis, Orthetrum coerulescens and Sympecma fusca could be found in the
coming years also in Latvia. At the same time, the detection of Sympetrum depressiusculum and
S. eroticum, founded in Lithuania close to Lavia, are unlikely, because the main distribution area of
the S. eroticum embraces China, Japan, Korea and the Far East of Russia (Wilson 2009), and
identification of S. depressiusculum is probably unreliable (P. Ivinskis, personal communication).
The appearance of new species is the counteraction to the changes of environmental factors,
but the changes of environmental factors, in their turn, influence life histories of species –
development, diapason, phenology, thermoregulation as well as ecology (Hassal, Thompson 2008).
It means that in future studies more attention should be paid both to factors that determine the
arrival of new species into Latvia and to the influence of these factors and the new species on the
native species of the Latvian dragonfly fauna. For example, will the populations of Anax imperator
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