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Efekt podpory výskytu přirozených predátorů škůdců na zdraví a vitalitu ovocných dřevin
Bernatová, Martina
Predators (both invertebrates and vertebrates) can have a positive or negative effect on the vitality and physiological processes of woody plants. However, the mutual effect and interaction of several different groups of predators and their influence by different habitat manipulations is still not well known. For this reason, the aim of my work was to find out how biological control, i.e. manipulation to support invertebrate predators, and, conversely, the exclusion of insectivorous predators from vertebrates (birds, bats), or a combination of these two manipulations, will affect the vitality (and health status) of fruit trees, specifically pear. The experiment took place in organic pear orchards in the Zlín and South Moravian Regions. In each orchard (n = 4), 16 trees were selected and divided into groups of 4 trees differing according to the type of manipulation: a) installation of cardboard bands to support invertebrate predators, b) construction with a net to exclude the access of birds and bats, c) combination of cardboard bands and structure with net, d) control tree. The experiment started in the autumn of 2021 with the instalation of cardboard bands and in the spring of 2022 with the instalation of structures with nets for exclusion of birds. During the season (from May to September 2022), samples were collected to determine and compare leaf biomass and herbivory, fruit biomass and damage, and the efficiency of photosynthesis and the content of chlorophyll in the leaves were also measured, as well as the leaf area index. Overall, the results showed a significant positive effect of the manipulations on pear vitality. The best vitality was recorded for trees with a combination of cardboard bands and exclusion of birds and bats. The results show the importance of supporting natural predators of pests (mainly spiders). On the contrary, it is evident that these interactions could be disturbed by insectivorous birds (bats), which have a significant predation effect on spiders and thus can have a cascading effect on the vitality of fruit trees.
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Druhová diverzita, početnost a význam pavouků (Arachnida, Araneae) na listnatých dřevinách v arboretu Mendelovy univerzity v Brně
Bernatová, Martina
The aim of my work was to find out the species diversity and the number of spiders in the arboretum of Mendel University in Brno and also to deduce their significance and last but not least to assess the importance of arboretums, parks and other urban greenery as areas of biological diversity in urban areas. Within the research fifteen deciduous trees were selected, located in different parts of the arboretum. The spiders were collect by using two capture methods, a shaking off method and a selection of cardboard belts method. Shaking off took place within the research four times, namely 11.5.2017, 14.6.2017, 1.8.2017 and 18.9.2017. A selection of cardboard belts took place twice, 28.6.2017 and 19.10.2017. In both methods, a total of 303 adult specimens of spiders belonging to 45 species, 36 genera and 14 families were obtained and determined. The most frequently represented was the species of Philodromus cespitum, which accounted for more than a third of the captured material (over 33%). This species belongs to species capable of living even in disturbed biotopes of urbanized areas, so its considerable representation is expectable. Within the research, however, several threatened species were acquired, species that occur only in a natural, undisturbed environment. From this fact, it can be concluded that the environment of the arboretum is at least partially a natural environment for the occurrence of different species, from which it can be deduced that arboretums, parks and similar greenery in cities are indeed a place of biodiversity. This conclusion is important also for arboristic practices, as well as the fact that spiders are important invertebrate predators and can therefore be used for biological protection in cities (where it is inappropriate to use chemical preparations for plant protection) and also outside them. Endangered and rare species that have been identified in the arboretum within the research can also be used to bioindicate the quality of the environment in the arboretum and similarly spiders can be used for the bioindication in urban parks and other urban greenery as well as in open landscapes.
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