Odonata - Entomological Society of Latvia - Latvijas Daba

5. CONCLUSIONS
1. In line with the latest investigations, there are 59 dragonfly species in Latvia. The changes in
Latvian dragonfly fauna in the last 20 years are related to the extension of southern species
areas in the northern direction. In future 5 new dragonfly species may be identified in
Latvia – Lestes viridis, Erythromma viridulum, Aeshna affinis, Orthetrum coerulescens un
Sympecma fusca, while the total number of new species in a larger period of time might
reach 12 species. The foreseen changes in the dragonfly fauna are related to the distribution
of southern species in the northern direction.
2. The distribution of separate dragonfly species in Latvia is very irregular, as Latvia lays in
the periphery of the species’ area (Coenagrion johanssoni) and due to disjunctive
distribution of species habitat (Gomphus flavipes, Aeshna subarctica) and climate changes
(Anax parthenope, Sympetrum fonscolombii, Sympetrum pedemontanum).
3. The variety of dragonfly species found in raised bogs is increased by the presence of water
pools in open landscape (less common are pools in pine groves). Low variety of species is
found in wooded mire (wooded [pine groves] mire landscape with mounds and depressions)
and open mire (open mire landscape with mounds and depressions, but with no water bodies
or woods) habitats. For dragonflies, the most important structures are open water and Ledum
palustre, Vaccinium uliginosum, Calluna vulgaris and Andromeda polifolia vegetation
structures.
4. In the research of river dragonflies Gomphidae it was found that Gomphus vulgatissimus is
an ecologically flexible species and the highest density of population can be found in micro
habitats with sand and mud (and lower speed of the stream). Onychogomphus forcipatus, on
the other hand, is less flexible and the highest density of larvae population is found in micro
habitats with gravel, pebbles and cobbles (and higher speed of the stream). For
Ophiogomphus cecilia the density of larvae population is relatively low, but no specific
micro habitats were identified in Latvia.
5. In Latvia, contrary to other European countries, Nehalennia speciosa may populate both
small and large water bodies, if the vegetation is appropriate for the species. The distribution
of the species in Latvia is most likely determined by the climate – the level of moisture and
continentality of the climate. Fundamental differences regarding the vegetation populated by
the species and the size of populations were not established.
6. Aeshna subarctica in Latvia populates raised bogs with water pools and lakes and lakes with
fen and poor fen banks, but, unlike in other European countries, it is not found in peat
quarries. The distribution of the species in Latvia is most likely determined by the climate –
the level of moisture and continentality of the climate. Fundamental differences regarding
the size of the populated water bodies and populations were not established.
7. Ophiogomphus cecilia in Latvia populates similar river habitats as in other places in the
species area. Unlike in case of the part of the species area on the south from Latvia, in
Latvia the distribution of the species is more determined by the climate – the level of
moisture and continentality of the climate.
8. The population of Leucorrhinia family dragonflies in Latvia, in comparison with the
population of this species in other places in Europe, is quite small. L. albifrons are more
often found in dystrophic (acidic) lakes and also habitats of anthropogenic origin;
L. caudalis comparatively often can be found in oxbow lakes, which is more characteristic
to the periphery of the species area; the number of new localities of L. pectoralis has grown
considerably, despite the downward tendency in Europe. The habitats suitable for these
species are characterized more by the vegetation of the habitat rather than its origin
(naturalism).
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