Odonata - Entomological Society of Latvia - Latvijas Daba

1.2. THE AIM, TASKS AND THESES
The aim of the Doctoral thesis is to identify the regularities of the changes of dragonfly
(Odonata) fauna and species distribution in Latvia, as well as the factors influencing the population
of some species.
In order to achieve the goal of this paper, the following objectives were set:
5. To investigate the changes of the faunistic composition in Latvia and to identify the changes
in dragonfly distribution and their causes.
6. To define the influence of the raised bog micro habitats and vegetation structure on the spatial
distribution of dragonfly imagines in raised bog habitats.
7. To define the influence of the micro habitats on the occurrence and the density of population
of the Gomphidae family dragonfly larvae in rivers.
8. To investigate the distribution of Europe endangered and internationally protected dragonfly
species in Latvian habitats and micro habitats.
Theses:
5. The number of dragonfly species registered for the first time in Latvian fauna has grown
considerably in the last 20 years. An extension of southern 2 species’ areas in the northern
direction has been observed; this is related to climate changes. The distribution of dragonfly
species in Latvia is very irregular and changing.
6. Different dragonfly species (imagines) are related to different oligotrophic micro habitats and
vegetation structures.
7. The occurrence of the Gomphidae family dragonfly larvae and the density of population are
influenced by various characteristics of river micro habitats.
8. The distribution and habitats and micro habitats populated by some Europe endangered and
internationally protected species in Latvia differ from the distribution and habitats and micro
habitats populated by the same species in other places in Europe.
1.3. SCIENTIFIC NOVELTY OF THE STUDY
The research for the first time describes the changes in the composition of Latvian dragonfly
fauna in a longer period of time. Also, for the first time in the last 20 years, the occurrence of
southern species is described. The maps of dragonfly distribution have been developed, including
all known data on the species in the territory of Latvia, as well as the changes of species distribution
have been described.
New information has been provided regarding the role of micro habitats and vegetation
structure in the distribution of the imagoes of various dragonfly species in oligotrophic micro
habitats. This considerably improves the understanding of the spatial distribution of dragonflies in
the oligotrophic micro habitats of Europe.
The research on the influence of river micro habitats on the occurrence of the dragonfly
larvae and the density of dragonfly population provides a new knowledge and expands the existing
one about the preferred micro habitats and the density of the population of the Gomphidae family
dragonfly larvae.
The knowledge about some endangered and internationally protected dragonfly species in
Europe, their distribution, populated habitats and micro habitats in the Baltic’s and the Northern
European region have been considerably expanded. For some species, it has been observed that the
distribution and habitats and micro habitats populated by some endangered and internationally
protected species in Latvia differ from the distribution and habitats and micro habitats populated by
the same species in other places in Europe.
2 Species, the areas of which are situated to the South from the territory of Latvia
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