|
|
Spatial distribution of eastern ground beetles in the pond
KADLEC, Bohdan
Stone Moroko is one of the non-native fish species in our territory. It is a small carp fish whose origin is in Asia. In many places in the Czech Republic or in abroad, their presence cause damage. The aim of my Bachelor Thesis was to find out more about the behaviour of this weed fish. We were interested to know, how far from the shore it stay. Whether its activity is more intense during the day than at night. Whether the fish appear more at the surface or at the bottom. There were performed 5 measurements on the Kvítkovice pond, each took 24 hours. The measurements were carried out from June till October 2021. The pond was divided into 5 different parts A, B, C, D, E. Piles were used to obtain samples. These were located at the different distances from the shore. In some places, where the depth of the water allowed it, 2 piles were used. One was placed on the bottom and the other one on the surface. Samples were also collected by using a throwing net. At each of the localities A, B, C, D, a throwing net was thrown 5 times in the area of the littoral. Site E was located in the middle of the pond, so catching by the throwing net did not take place here. Water sampling was also monitored at 6 different locations for each sampling. We managed to catch in total 50 fish using a throwing net and 267 fish by using the piles. Four species were represented: Stone Moroko (Pseudorasbora parva), Pumpkinseed (Lepomis gibbosus), Brown Bullhead (Ameiurus nebulosus) and Common Carp (Cyprinus Carpio). Our results show that the activity of weed fish species is higher during the day than at night. We managed to catch 75% of the samples during the day, but only 25% during the night. The Stone Moroko remained more at the bottom, unlike the Pumpkinseed, which occurred mainly at the surface. There was a statistically significant decrease in the number and weight of Stone Moroko with increasing distance from the shore. However, this trend has not been statistically confirmed for variegated Pumpkinseed. The Stone Moroko preferred localities A and C. Pumpkinseed preferred localities D and E. Site B was equally preferred by both species. The most suitable months for obtaining samples are July, August and September. The calculated fish biomass in July was 2.07 kg.ha-1, in August 8,079 kg.ha-1 and in September 2,964 kg.ha-1.
|
|
|
The response of Marsh Frog (\kur{Pelophylax ridibundus}) to the presence of alien predators
KROUFKOVÁ, Michaela
This study focuses on the antipredator strategies of amphibian larvae in relation to some of their predators. Namely, the relationship between the larvae of the marsh frog (Pelophylax ridibundus) and the invasive species of the fish, the topmouth gudgeon (Pseudorasbora parva). Latter part of the experiment involves investigation into the relationship between another non-native species, the three-spined stickleback (Gasterosteus aculeatus). Both are non-native species of small fishes. The topmouth gudgeon was introduced unintentionally in the 1980s from Hungary. It is listed on the Black List of the Czech Republic and it is on the list of invasive non-native species of the EU Regulation (1143/2014), (Kuřátko, 1998; Poláková et al., 2016). The three-spined stickleback was brought into our territory from America. It was probably released into local ponds by Czech aquarists at the beginning of the 20th century. It is a species that is not listed on the Black List of the Czech Republic, but its negative impact on fish fry has been previously documented (Poláková et al., 2016). Both species have been known for a negative impact on the biological diversity of our fauna, but the influence of these predators on our amphibians has not so far been documented. The experimental part investigates the damage of tadpoles caused by these non-native fishes and the defensive strategy of the tadpoles. The tadpoles were provided with a hiding place as one of the possible escape strategies against the predator.
|
|
|
Non-indigenous freshwater fish species of the Mediterranean basin of the Balkans
Balog, Štefan ; Vukićová, Jasna (advisor) ; Švátora, Miroslav (referee)
Mediterranean basin of the Balkan Peninsula is one of the hot-spots of biodiversity, with a high diversity of freshwater fishes and high degree of endemism. Introduction of non-native species greatly affects ecosystems and native species of fish. There were many reasons for introductions in the past. Aquaculture, sport fishing and ornamental fish belong to the most important reasons for introduction of non-native fish species. Altogether, 39 species belonging to 12 families were introduced in the Mediterranean basin of the Balkan Peninsula. Most of them belong to the families Cyprinidae and Salmonidae. Introduction of fishes was known since the Roman era. Although the first recorded introduction in this area was in the 13th century, most species were introduced in 20th century. The fishes were introduced from North America, Europe and Asia. Many translocations occurred in this area, too. Translocation is a relocation of particular species within one area. The most widespread introduced species in the Mediterranean basin of the Balkans are common carp (Cyprinus carpio), stone moroko (Pseudorasbora parva), rainbow trout (Onchorhynchus mykiss), mosquitofish (Gambusia holbrooki), goldfish (Carassius auratus) and sunfish (Lepomis gibbosus). Hybridization, competition, pathogen transmission and predation...
|
|
|
Relationship between species diversity, temperature and productivity for native and non-native plant species
Szostoková, Kateřina ; Šímová, Irena (advisor) ; Hejda, Martin (referee)
Latitudinal gradient of diversity is typically being explained by the three main hypotheses: The Resources Limitation Hypothesis, The Speciation Rate Hypothesis and The Niche Conservatism Hypothesis. In my study I tested basic assumptions of these hypotheses using native and non-native vascular plants obtained from the new database GloNAF (Global Naturalized Alien Flora). I tested an effect of precipitation, NPP, temperature and historical velocity (difference in temperature and precipitation between the Last Glacial Maximum and present) on species richness. Given that the distribution of non-native species is among continents irregular (we can divide them into two groups - Australia with Europe and North America and South America with Africa and Asia), I tested the abovementioned relationships at both - global and continental scale. Species richness of native species increased with NPP, precipitation and temperature and decreased with the difference in temperature. The global distribution of non-native plants increased with precipitation and temperature velocity and decreases with temperature and precipitation velocity, although the results varied for particular continents. Unlike other studies the number of non-native species didn't correlate with the number of native plant species. Concurrently...
|
|
|
Problems of hybrids and non-native species of falconry birds of prey (Falconiformes)
RICHTROVÁ, Zuzana
There have been more and more discussions of the influence of falconry on wild populations of birds of prey in recent years. Where the main topic previously dealt with stealing young birds from nests, today's concerns revolve around interspecific hybrids and non-native species. This thesis therefore focuses on these issues and attempts at collecting available information. The main finding is that only few serious researches have been carried out on this topic so nobody can make a conclusion that would subsequently lead to practical interventions. The available sources clearly show that non-native species are most likely not to pose any risk to nature. In contrast, the information on hybrids was very inconsistent and often diverged. It is probable that hybrids have some influence in nature; but to determine its severity and whether or not intervention is required, we need to carry out a detailed scientific study. IAF (International Association for Falconry) recommends a number of measures that seem to be sufficient at the time and they include: - ban on arbitrary discharge of hybrids and non-native species into the wild - ban on free-hacking while training these birds - requirement to use telemetry in training - requirement to use maximum effort in order to trace these birds in case they get lost - imprinting of young hybrids in species that is not found in nature in the given area Improvement should mainly be made in the registration of birds of prey. At this point and in most countries, it does not allow you to trace the birds' parents reliably and, as a consequence, one cannot unambiguously determine whether the bird in question is a hybrid or pure species.
|
|
|
Numbers of non-native waterfowl species in Europe
Hodková, Veronika ; Musil, Petr (advisor) ; Šťastný, Karel (referee)
The Thesis is treating the spreading of non-native waterfowl species into new ecosystems and factors, which influence that process. The impact of selected eco-geographic characteristics on the species diversity and on the numbers of non-native waterfowl individuals was analyzed on the results of the International Waterbird Census. Further, the influence of those characteristics on the numbers and population trends of selected 11 species of the Anatidae family in 17 European countries was assessed. The highest non-native waterfowl species diversity was recorded in countries of the Atlantic coast, i.e. France, Germany, the Netherlands, Belgium and also Switzerland. The main positive influence on their numbers makes the density of population and species diversity of wintering waterfowl. As to the number of non-native species individuals the main impact is produced by both, species diversity and the given latitude, too. It means that the largest number of individual exist in northern countries - Great Britain, Sweden, Germany and the Netherlands. Similar main influences have been traced with the family Anatidae, too, which have received special attention in the analysis, as it shows the highest number of non- native species. As to the main eco-geographic characteristics, having impact on the growth or...
|
|
|
Biology and invasive spreading of signal crayfish (Pacifastacus leniusculus) in the Vysočina Region
JUREK, Lukáš
This thesis deals with the issue of non-native crayfish species in Europe, focusing mainly on the Czech Republic. The main species of interest was the signal crayfish. Its biology in relation to invasive spreading was evaluated. The most recent list of its known populations in the Czech Republic was compiled. These data were subsequently compared, updated and enriched with new locations based on this field monitoring. Its occurrence was evaluated largely in the Vysočina Region, in the area of Velké Meziříčí. As it turned out, the center of the signal crayfish occurrence in the Czech Republic is located really in the area of its original introduction thirty years ago in our country, in the vicinity of the Velké Meziříčí. During that time, signal crayfish have successfully expanded into the surroundings waters, both naturaly (downstream and upstream migration) and with human aid (with restocking fish, direct distribution by the public). It occupied all possible types of habitats, from running waters of the two major rivers Balinka and Oslava to their tributaries creeks of different size and character. It found suitable living conditions also in some ponds, particularly those less intensively farmed. Signal crayfish was recorded in areas, where noble crayfish Astacus astacus is still relativelly widely present, in some place even forming sympatric populations. The work was also focused on epibionts Branchiobdella sp., their presence or absence on caught crayfish. Their occurance was also recorded and evaluated.
|
guest ::
