|
|
Application of bioacoustic approaches in investigation of bird species interactions and community species richness
Vokurková, Jana ; Sedláček, Ondřej (advisor) ; Remeš, Vladimír (referee) ; Szymański, Paweł (referee)
Birdsong is one of the most fascinating communication tools in the animal kingdom, whether it is used for attracting a mate or in territory defense. In my dissertation, I present evidence that we can successfully study the role of birdsong in territorial behaviour, its seasonal variability, and ultimately its role in evolutionary processes thanks to modern bioacoustic and ecoacoustic approaches. By combining the bioacoustic approach with molecular analyses, I demonstrate that in the model system of two closely related passerine species, the heterospecific song convergence in their secondary contact zone is based on cultural transmission, and not on interspecific hybridisation and/or gene introgression. My dissertation further extends into the tropical zone, which is generally characterized by less pronounced environmental seasonality compared to the temperate zone. The study of potential seasonality in singing activity and the proportion of vocalizing species in this zone therefore requires year-round monitoring, which is possible thanks to the quite recent development of automated recording units (ARU). First, we confirmed that using ARU provides very similar estimates of community composition, species richness, and abundance to traditional field methods (point counts) in the specific conditions...
|
|
|
Environmental determinants of bird species richness and population densities in sub-Saharan Africa
Dubský, Marek ; Sedláček, Ondřej (advisor) ; Reif, Jiří (referee)
The research of factors influencing bird's species diversity and abundance will allow us to manage the landscape in the way to create suitable conditions for survival of species. For the purposes of this work, I divided bird assemblages into 3 groups on local level: forest birds, shrubland birds and grassland birds. The forest bird species were most influenced by height of canopy, its compactness and fragmentation of the forests. The size of the fragment, fragment matrix, isolation of the fragment and birds sensitivity to edge effect were deciding factors of number of species and individuals in each fragment. The shrubland birds were most influenced by vegetation structure in meaning of presence of shrubs, trees and grassland. They were also influenced by vegetation species composition, frequency and form of disturbances (fire, grazing), they reacted positively to transformation of landscape into agroecosystems and they reacted negatively to shrub encroachement. Grassland birds reacted to various height of grass, they reacted negatively to presence of trees and shrubs and also to disturbances caused by human. It is the least studied group of birds in Africa. As fot the elevation gradient, the lowland assemblages of birds changed to mountains assemblages at attitude of about 1250 above the sea...
|
guest ::
