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The relationship between spatial scaling of biodiversity and the number of individuals
Dlouhá, Hana ; Storch, David (advisor) ; Šizling, Arnošt Leoš (referee)
The patterns connected with increasing number of species while enlarging studied area (species-area relationship, SAR) remained one of the most studied topics in ecology. In the past, papers presenting single SAR curves prevailed. Recently, also unifying works have appeared. One approach has focused on the possible relationship between mean number of individuals per species and the rate of increase of number of species with area. According to this theory higher mean species abundance leads to lower values of SAR curve slope. Moreover, there is one prediction based on maximization of entropy principle (MaxEnt) that is able to give us particular values of SAR's slope when we provide the values of mean species abundance. There are also other approaches except for MaxEnt one that deals with mean species abundance and reached similar results. The main aim of this work was to gather all possible data about slopes of SARs and mean species abundances and find out possible relationships between these two variables. I have also included several other variables into the analyses to reveal the importance of them as predictors for the values of the slope. I performed two main groups of analyses. At first I focused on overall slopes of SAR curve (overall slope represents the slope of a line that resulted from...
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Limitation of species richness
Szostoková, Kateřina ; Storch, David (advisor) ; Šímová, Irena (referee)
Currently we can find two main hypotheses of diversity dynamics in time in literature - bounded and unbounded hypothesis. According to bounded hypothesis diversity is limited, while unbounded hypothesis says that there are no obvious limitations of diversity. Evidence for these main hypotheses comes mainly from paleontological research, studies of phylogeny and comparison of local and regional diversity. None of these approaches give us clear and incontrovertible evidence of diversity limits. The aim of this work is to show some evidence that confirm (or not) limitation of diversity in mentioned kinds of biological research. Also, I would like to point out some critics and imperfections of used methods.
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The relationship between diversity patters, spatial distribution and life-histories in African birds
Tószögyová, Anna ; Storch, David (advisor) ; Šizling, Arnošt Leoš (referee)
Species with particular traits are not randomly distributed across landscape. Habitats provide the templet on which evolution forges characteristic morphologies and life-history strategies and environmental determinants in an ecological processes represent a filter for certain species with appropriate traits. It is essential to understand how spatial differences in community composition are affected by geographical patterns in a distribution of species characteristics. I was interested in searching and determining the relationships between species traits and environmental parameters within avifauna of south Africa. I investigated the effect of which variables of environment most influenced bird assemblage composition and distribution of species traits in space. Relationships between the environmental factors and the species traits and life-history stategies were investigated using RLQ analysis, a multivariate ordination method able to relate a species trait table to an environmental table by way of a species presence/absence table. The first axis of the RLQ analysis was highly statistically significant and explained most of the variability. It was strongly positively related to increasing productivity, to atributes reflecting vegetation character and to availability of water sources. The rest of...
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Relationships between functional traits, home range sizes, and dispersal abilities in birds
Holubová, Kateřina ; Storch, David (advisor) ; Sedláček, Ondřej (referee)
Avian movements through the landscape involving dispersal and routine movements within home-range or territory are one of the basic but due to a high mobility of birds also one of the least understood processes of bird ecology, especially on the interspecific level. Not only is dispersal a fundamental mechanism of species' spreading into new areas, but also, together with home-range size, it shows the scale on which species perceive the landscape and how they can deal with habitat changes. Dispersal ability, represented by dispersal distances, is determined by a few species specific traits like body size, migratory status, wing and bill morphology, diet type, preferred habitat type or some life-history traits. On the contrary, home-range size variability is determined primarily by energetic demands of the species, given by its body size and trophic level, and by the productivity of the environment. There is a positive relationship between home-range size or territory size, respectively, and dispersal distances of birds that can be attributed to species vagility or their spatial requirements determined especially by their food preference. Nevertheless, further research mainly on interspecific level is necessary for a deeper insight into this issue.
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Mechanisms of species-energy relationships across spatial scales
Šímová, Irena ; Storch, David (advisor) ; Kühn, Ingolf (referee) ; Lepš, Jan (referee)
Explaining spatial variation of species richness is a central goal of ecology. Recently it has been shown that the number of species is related to energy availability. There are two major categories of hypotheses concerning possible processes behind this relationship: i) hypotheses based on an assumption that the total number of species at given site is limited by the total amount of resources, and ii) hypotheses assuming that evolutionary and historical processes are mainly responsible for the current species richness patterns. We tested possible explanations concerning both resource limitation and evolutionary history using datasets of herbaceous plants, trees and dragonflies, varying in their scale and extent. Within local communities of herbaceous plants, the number of species was influenced by the total amount of available resources (productivity), through its effect on the total number of individuals and the intensity of interspecific competition. However, the role of resource limitation was not strong, and the form of the resulting species-productivity relationship was affected by habitat heterogeneity acting independently of productivity. Historical processes affecting the size of species pool appeared also as important at this scale (Chapter 1). Within local communities of trees...
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Latitudinal gradient of biodiversity and its dependence on rate of ecological processes and evolutionary processes
Krupička, Jan ; Storch, David (advisor) ; Kubička, Lukáš (referee)
Unevenness in the distribution of species diversity on the surface of the earth is one of the most striking phenomena in ecology. Latitudinal gradient of biodiversity could be explained by different rates of evolutionary processes such as speciation and ecological processes that control the ratebof extinction. The goal is to collect and evaluate the literature on the temperature dependence or latitudinal trends in the rates of these processes. Matabolic theory of biodiversity serves as the best explanation of the rates of evolutinary processes and their dependance on temperatur, while an explanation of the rate of ecological process is lacking in empirical data and theories that would put them in relation to temperature and latitude. Explanation by More individual hypotheisis was proved unconvincing.
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The factors affecting evolutionary diversification
Černá, Vladimíra ; Storch, David (advisor) ; Kratochvíl, Lukáš (referee)
The number of species on the Earth is estimated to lie between five to ten millions. All these species originated from a common ancestor, which appeared on our planet 3,5 bilion years ago. Speciation and extinction are responsible for the current species richness. Evolutionary diversification is the difference between speciation and extinction. There are several methods used to obtain the values of speciation, extinction and diversification rates. I will briefly explain some of these methods, outline the advantages and disadvantages of them. The aim of this paper is to summarize current knowledge of evolutionary diversification and factors that may affect it. In this search I focused on the studies dealing with factors that may affect several groups of organisms. Although many determinants of diversification were found, most of them affect only one group of organisms. Here I did not find any factor that would be common for the majority of taxa. Evolutionary diversification is probably influenced by different factors in different evolutionary lineages. Key words: diversification, speciation, radiation, diversity gradient
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The relationships between diversity patterns and community abundance
Dlouhá, Hana ; Storch, David (advisor) ; Keil, Petr (referee)
Increase in the number of species with area is one of the most studied ecological patterns. There is a considerable amount of literature devoted to this question. The rate of increase in the species diversity with area isn't equal at all the spatial scales, as shown by empirical studies. On the finest and coarsest scales, there is distinctively higher rate of increase than on the middle (regional) scales. These distinctions were attributed to many characteristics of environment, taxon etc. There is a possibility to explain the variability of this particular rate by mean species abundance. This work focuses on summarizing the relationships between the rate of increase in biodiversity with area, factors that influence it and mean species abundance.
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Macroecology of European invertebrates:temporal and spatial patterns extracted from heterogeneous data
Keil, Petr ; Storch, David (advisor) ; Lepš, Jan (referee) ; Kindlmann, Pavel (referee)
Univerzita Karlova v Praze Přírodovědecká fakulta Katedra ekologie Makroekologie evropských bezobratlých: časové a prostorové patrnosti dobývané z heterogenních dat Autoreferát dizertační práce Petr Keil Školitel: Doc. David Storch, Ph.D. Praha 2010 Charles University in Prague Faculty of Science Department of Ecology Macroecology of European invertebrates: temporal and spatial patterns extracted from heterogeneous data Ph.D. thesis - summary Petr Keil Supervisor: Doc. David Storch, Ph.D. Prague 2010 SOUHRN Dizertační práce obsahuje pět kapitol. První čtyři kapitoly jsou věnovány několika aspektům makroekologie evropského hmyzu, jako jsou geografické a časové patrnosti druhového bohatsví. Pátá kapitola zkoumá některé makroekologické charakteristiky populační dynamiky v rámci neutrální teorie biodiverzity. Dizertace je opatřena úvodem, který se věnuje zejména metodickým problémům společným pro většinu kapitol. V Kapitolách I a II jsem se zabýval rozmístěním druhového bohatství pestřenek (Insecta: Diptera: Syrphidae) a vážek (Insecta: Odonata) napříč Evropou. Obě práce ukazují absenci jednoduchého poklesu druhového bohatství od jihu k severu. Druhově nejbohatší jsou horské oblasti kolem Středozemního moře, od kterých směrem na jih a na sever diverzita klesá. V obou případech se jako důležité proměnné...
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