EVOLUTION OF AN ECOLOGICAL SYSTEM–FORMATIONS
OF THRIPS (INSECTA: THYSANOPTERA)
AND PLANT ASSOCIATIONS. A CASE STUDY
W. Sierka, E. Sierka
University of Silesia, Katowice, Poland, E-mail: firstname.lastname@example.org, email@example.com
Key words: Thysanoptera, thrips, mid-field scrub
В. Сиерка, E. Сиеркa
Унисерситет Силезии, Катовице, Польша, E-mail: firstname.lastname@example.org, email@example.com
Ключевіе слова: Thysanoptera, трипсы, кустарник
The work presents the results of investigations into the relationship between phases of development of mid-field shrub associations (Pruno–Crataegetum) and thrips communities (Thysanoptera) in the Jaworzno Hills area (the Silesian Upland, southern Poland).
In the past the area of the Jaworzno Hills was covered mainly by dry-ground forests, beech woods and mixed-coniferous forests, which were gradually stumped and turned into fields. Today most of the region’s arable lands are not cultivated, which is conducive to the development of mid-field shrubs; moreover, the fields are no longer subject to a regular agricultural treatment. Because of their high floral diversity (and rich food resources thus offered), which is enhanced by the transitional character of shrub associations between forest complexes and open fields, mid-field shrubs enrich the flora and fauna of deforested areas.
This project attempts to determine the relationship between the phase of development of mid-field shrub associations and the structure of thrips communities. Moreover, it aims to demonstrate that it is possible to use the parameters of the insect community structure in the evaluation of the distortion of plant associations.
Thrips were collected from patches of shrubs in different phases of development. Insects were identified to the species level and classified within main ecological groups as species connected with open areas, with forests, and ubiquitous forms. At the same time, phytosociological photographs were taken to determine the qualitative and quantitative composition of the phytocenoses.
The obtained data were analysed for particular developmental phases (initial, optimal and terminal) of mid-field shrubs, which were treated as stages of succession (the chronosequence approach).
On the basis of the zoocenotic indices calculated for particular thrips species, it was established that there is a straightforward correlation between the species composition of the plant associations and the structure of thrips communities. Moreover, an attempt was made to create a model which would represent the pattern of interdependence developing between the animal community and the type of plant association in relation to time and space. This model was then compared with zoocenoses of other plant associations – forest and meadow.
Basing on the results obtained from 27 patches of mid-field shrubs, a total of 52 plant species and 45 thrips species were found. As succession proceeds (successive developmental phases of the shrubs), the role of thrips of forest areas increases, while that of thrips living in open areas is minimised. In the initial phase of shrub development, the occurrence of one or several dominant species was recorded. These species play a major role in the formation of the structure of the community. Regarding the species composition, the terminal phase of shrub development resembles Querco–Fagetea forest associations.
It seems that mid-field shrubs are propagation centres for some thrips and function as environmental islands for forest species of this insect group.
The authors suggest that mid-field shrubs should be protected because of their importance for the conservation of natural habitat diversity, their contribution to the landscape and their biocenotic function (shrubs are a substitute for forests).
Zoocenosis — 2005
Біорізноманіття та роль зооценозу в природних і антропогенних екосистемах: Матеріали ІІІ Міжнародної наукової конференції. – Д.: Вид-во ДНУ, 2005. – С. 304-305.