|
|
Species-area relationship in birds: variation across temperate zone environments
Gaigr, Matěj ; Hořák, David (advisor) ; Hanzelka, Jan (referee)
The relationship between area and number of species is one of the oldest and most studied principles in ecology, often referred to as one of the laws of ecology. Ecologists use it primarily to model the expected number of species in a given area. The Species-Area Relationship (SAR) states that the larger the area being, the greater the number of species present. However, area is not the only factor influencing species diversity - habitat heterogeneity is also a frequently studied factor affecting species richness. The number of species in an area tends to be positively influenced by heterogeneity since factors that are positively correlated with heterogeneity have a large influence. These factors include the species diversity of vegetation, the level of energy productivity, the number of microhabitats, the effect of disturbance or the amount of different food sources. Individual temperate habitats differ in the relative contribution of heterogeneity in its impact on observed species abundance. Species abundance is not only influenced by habitat heterogeneity, but also by other factors such as altitude, climate or latitude. The most affected habitats regarding the relative contribution of heterogenity are forest environments. Vertical diversity is the main influence causing high heterogeneity in...
|
|
|
Variabilita plevelové vegetace a zaplevelení pozemků s ozimou pšenicí a bramborami v regionu jihozápadní Moravy
Stuchlíková, Irena
In my diploma thesis I focused on the diversity of weed species and the infestation in winter wheat and potatoes. The observations were carried out on the grounds of a family farm in Southwest Moravia. In the first part of the thesis I focused mainly on the history of farming systems, the aspects of crop rotation in crop rotation and the demands of the crops to be included in the sowing process. At the end of this section, I looked at spreading weed seeds, dormancy, and seed supplies in the soil. During the field research, I focused on weed species recording and counting of individuals. The most significant difference in weed species composition was found for seasonality, weed species spectra recorded in May differ significantly from species spectra recorded in August. The influence of the crop and crop rotation had much lower effect as well as differences among years or among grounds.
|
guest ::
