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THE EFFECT OF AN INCREASING COVERAGE OF INVASIVE BLACK LOCUST ON BIRD COMMUNITIES IN FOREST STANDS
Kroftová, Magdalena ; Reif, Jiří (advisor) ; Ferenc, Michal (referee)
Biological invasions are one of the most important threats to global biodiversity and they were also found to negatively affect some bird species. Despite relatively large number of scientific studies dealing with the impacts of invasive plants on bird communities, their results are inconsistent, especially it is not clear how birds respond to increasing levels of expansion of invasive species in native species stands. Moreover, bird responses to plant invasions seem to depend on the ecological characteristics of individual bird species. This study contributes to elucidation of this problem; I investigated the impacts of black locust (Robinia pseudoacacia) invasion on bird communities in three types of forest stands with different levels of invasion: in stands containing solely the native oak (Quercus spp.), in partially invaded stands with different proportions of black locust and oak (mixed stands) and in pure black locust stands. Previous studies that examined birds in pure oak and pure black locust stands have found that they differ markedly in vegetation structure, but not in the total number of bird species. However, habitat specialists were associated with the oak stands, while generalists with the black locust stands. Therefore, I predicted that (1) the total species richness will be...
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Birds in vegetation of invasive allien plant species
Kroftová, Magdalena ; Reif, Jiří (advisor) ; Hanzelka, Jan (referee)
Invasive plant species cause changes in the environment of natural habitat biotopes, and their impact is therefore is probably one of the most important threats to global biodiversity leading to homogenization of local ecological assemblages. Plant invasions disrupt ecosystem stability, change their functioning and structure, cause habitat fragmentation and sometimes function as ecological traps. Many scientists study the impacts of invasive species but they have been focusing mainly on plant communities or invertebrates. Effects on vertebrates, for example on birds, are not sufficiently explored. Birds are important components of ecosystems though, they provide wide range of ecosystem services, regulate abundance of herbivorous insect and some are among the top predators. Birds in turn affect plants by dispersing their seeds but this relationship can sometimes be disrupted by plant invasion. This thesis deals with the impact of invasive plants on bird communities and aims a systematic evaluation and summarization of scientific literature on this topic. Results suggest that birds in invaded ecosystems suffer from higher predation levels, they have lower reproductive success species and diversity of bird communities is reduced. Factors underlying these patterns are a decrease in diversity and abundance of...
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