National Repository of Grey Literature 22 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
The role of biotic interactions in plant invasions
Štajerová, Kateřina ; Pyšek, Petr (advisor) ; Prach, Karel (referee) ; Richardson, David M. (referee)
- ABSTRACT - The loss of co-adapted and gain of novel biotic interactions during the invasion process influence the success or failure of introduced plants. Within the present thesis, I studied diverse biotic interactions, specifically the relationships between plants and their herbivores, pollinators, fungi, and resident plant communities, and how biotic interactions can be utilized in planning effective science-based management. With my collaborators, we combined the community and biogeographical approach with the reciprocal transcontinental comparison between Eurasia and North America, based on primary data collected in the field. Of numerous hypotheses for the striking success of invasive plants, the enemy release hypothesis (ERH) is one of the most frequently tested. It asserts that the greater performance of introduced plants in non-native ranges is due to the absence, or decrease, in regulation by natural enemies that are left behind in the native range. Our results, in a broad sense, supported ERH, but we found that the magnitude of herbivore damage is context-dependent, related to the feeding guild and origin of both herbivores and plant species and that the increased plant performance in a new range might also be related to other factors, such as the shift in plant competition. Of animal-plant...
Impacts of invasive plant species on European environment
Breburdová, Vendula ; Pyšek, Petr (advisor) ; Kindlmann, Pavel (referee)
The DAISIE project in the 6. framework program of the European Union provides valuable data about European invasive species. Invasive plants have various impacts, positive and negative, and effects all four types of ecosystem services (supporting, provisioning, regulating and cultural). Invasive species are also known to cause serious economic looses. The proposed work aims at summarizing the up-to-date knowledge about the impact of invasive flora on European environment and human well-being. key words: invasive plants, impact, DAISIE, Europe, ecosystem services
Factors associated with invasiveness in the genus Impatiens: interaction of species traits, competition and environment
Čuda, Jan ; Pyšek, Petr (advisor) ; Kollmann, Johannes (referee) ; Prach, Karel (referee)
The aim of this thesis was to identify factors that contribute to invasiveness of species in the genus Impatiens. This genus is horticulturally attractive and includes several species that are known to have naturalized outside their native ranges, while others did not escape, in spite of being frequently cultivated. When looking for traits associated with invasiveness, it is useful to focus on congeneric species. Their traits and dispersal modes are less influenced by phylogeny, than when comparing unrelated species or even complete floras. This helps to account for traits that favour invasive species over native ones and thus identify potential invaders more precisely. A superior invader performance is attributed to a competitive advantage over native species that can lead in extreme case to competitive exclusion of the latter. Invasive and native species com- pete only if their niches overlap and the strength of competition depends on niche similarity. Importantly, invasive species are considered to be able to maintain their high competitiveness over a wide range of environmental conditions, while native ones often have narrower environ- mental optima. Lastly, competitive outcome can vary over life stages and depends on the degree of species dominance, which is rarely taken into account. Spread and...
The effects of historical disturbances on current vegetation and invasive plant Heracleum mantegazzianum in the Slavkov forest
Breburdová, Vendula ; Pyšek, Petr (advisor) ; Münzbergová, Zuzana (referee)
The thesis deals with the differences in floristic composition of the vegetation in abandoned villages in the Slavkovský les forest and surrounding open landscape. Due to complex historical events, the villages were abandoned and demolished by the army. Vegetation survey took place in 13 completely destroyed villages, and since the vegetation in villages consists of a mixture of woody and treeless cover, the reference vegetation in the surroundings was selected to include both types of habitats. Total number of species, number of families, Ellenberg indicator values, number of archaeophytes and neophytes and representation of life forms were compared for the floras of villages and their surroundings. The flora of villages had more neophytes, phanerophytes and higher indicator values for nutrients and soil reaction. Species' positive fidelity and percentage frequency were calculated from the synoptic table. Indirect ordination plot (NMDS) and PERMANOVA test confirmed the differences between floristic composition in destroyed villages and their vicinity. The second part of the thesis explores the differences between floristic composition of plant communities by Heracleum mantegazzianum in the same two types of habitats. Based on 50 phytosociological relevés, the total number of species, number of...
Between-year dynamics of carnivores and ungulates in the Czech landscape
Schnebergerová, Adriana ; Pyšek, Petr (advisor) ; Sedláček, František (referee)
It is important for the ecological management of wildlife populations in the Czech Republic to know the composition of species in individual habitats. This will allow predictions on the reactions of wildlife based on evolving changes that will occur sooner or later in these habitats due to human activity and natural change of our environment. Camera traps are a powerful tool of the 21st century with which we are able to observe wildlife without major interventions in their lives. With the right experimental design, camera traps allow us to find out details about wildlife life such as their distribution and habitat preferences, population structure, and their behavior. In this work, I used camera traps to determine the species composition of two groups; ungulates and carnivores in different habitats. This thesis analyzes the habitat preferences and hepls to find out to what extent the spatial patterns of occurrence on these two groups are in the monitored habitats over the course of a couple years. Data collection took place from June 2015 to May 2017 in the Central Bohemian Region northeast of Prague. Despite the fact that the area is densely populated and agriculturally exploited, I was able to capture four species of ungulates and nine species of carnivores on a total of 73 camera traps in this...
Biotic threats to garden monuments: algae, cyanobacteria and invasive plant species
Pergl, Jan ; Perglová, Irena ; Albrechtová, J. ; Antl, Tomáš ; Abarenkov, K. ; Baldrian, Petr ; Cihlářová, L. ; Klečka, Jan ; Kohout, Petr ; Kvasničková, Jana ; Maršálek, Blahoslav ; Maršálková, Eliška ; Pejchal, Miloš ; Petružálková, M. ; Petřík, Petr ; Pyšek, Petr ; Sádlo, Jiří ; Štefl, Lukáš ; Tedersoo, L. ; Větrovský, T. ; Vlk, Lukáš ; Vojík, Martin ; Vosátka, Miroslav ; Zezulka, Štěpán
Chateau, city parks and gardens are perceived as harmonious parts of the landscape. Unfortunately, even these areas have to face various threats, and they can be a threat to the surrounding environment. The exhibition /catalogue presents a look at the organisms that threaten parks. These threats cover unwelcomed invaders covering invasive plants and small microorganisms in the soil, on facades, statues or in water. On the other hand, some species that are intentionally brought to the parks can be risky not only the gardens themselves but also their surroundings.
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15th Ecology and Management of Alien Plant invasions (EMAPi) book of abstracts: Integrating research, management and policy
Pyšek, Petr ; Pergl, Jan ; Moodley, Desika
Book of abstracts from an international conference on plant invasions held in Prague in September, 2019.
Communitiy level impacts of alien invasive plants and the role of native range habitats in plant invasions
Hejda, Martin ; Pyšek, Petr (advisor) ; Duchoslav, Miloš (referee) ; Tichý, Lubomír (referee)
Conclusions Categorization of the species studied according to their impact on invaded communities This study focused on neophytes, species introduced after 1500 A.D., because their impact on native vegetation is higher and more obvious than that of archaeophytes, introduced before that date, due to considerable invasion dynamics and relatively short residence time (Pyšek et al. 2002). The target neophytes, included in the study, differ strongly in their community level impacts. Impatiens glandulifera had a miniscule impact on species diversity and composition, both in the removal experiment and comparative study (Chapter I). This small impact is likely to be associated with this annual species' lower competitive strength, which has a modest root system and forms stands that are not homogeneous in terms of cover. The density of I. glandulifera populations is known to decrease during the vegetation season, as plants fall due the weight of climbers, which are common in invaded riparian communities (Calystegia sepium, Cuscuta europaea - see Beerling & Perrins 1993). Moreover, the character of communities in which I. glandulifera invades, mostly riparian nitrophilous vegetation, does not provide opportunities for competitively weak species even if they are not invaded. This vegetation is dominated by tall,...
Explanation and risk assessment of alien woody plants invasion in Central Europe by historical and ecological factors
Křivánek, Martin ; Pyšek, Petr (advisor) ; Prach, Karel (referee) ; Richardson, David M. (referee)
Conclusions The studies presented focus on the historical and ecological traits corresponding with the successful invasion process of alien woody plants in Central Europe. In regard to invasion biology, woody plant species are among the most problematic plant life forms and constitute a high proportion of the World's worst invasive species. The irreversible changes in ecosystems often caused by invasion of these species constitute one good reason for study. The second is the large amount of data available, especially on human influence and activity (such as the intensity of planting, residence time). The reason for studying alien woody species is also reflected in their ambivalence: on the one hand, the group is represented by the most serious invasive species, while on the other hand, there is still strong pressure to plant these species for timber, food and ornamental purposes. The native woody flora of the Czech Republic contains about 280 species. The exact number of alien woody species in not known. Based on different approaches and datasets, it has been estimated to be in the order of 4,300 species. Exact data is available for a representative sample of frequently-planted alien woody species that contains 1,691 species. An estimated 128 alien species have escaped from cultivation, of which about 17...

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