Ekologické a evoluční procesy určující strukturu sítí rostlin a opylovačů

Abtrakt Rozmnožování většiny druhů rostlin a potrava značné části diverzity živočichů na této planetě přímo závisí na vztazích mezi květy a opylovači. Donedávna se však převážná většina výzkumu opylování zaměřovala pouze na studium opylování konkrétních rostlin a jen málo pozornosti bylo věnováno celým společenstvům rostlin i opylovačů. V posledních desetiletích se však zaměření ekologie opylování posunulo díky zavedení konceptu opylovacích sítí. Tento koncept umožnil zabývat se opylováním v kontextu celého společenstva, poukázal na rozmanitost i komplexitu vztahů mezi rostlinami a jejich opylovači a otevřel řadu nových možností výzkumu těchto vztahů z pohledu jeho významu pro živočichy nebo z pohledu časové a prostorové dynamiky opylovacích interakcí. Přesto však dosud máme jen matné představy o tom, jaké procesy jsou zodpovědné za strukturu a dynamiku těchto sítí. Podoba opylovací sítě je formována jak ekologickými, tak evolučními procesy. Z ekologického pohledu hraje roli například to, jak se druhy v čase a prostoru potkávají nebo jak si jednotlivé taxony opylovačů vybírají mezi rostlinami v závislosti na kontextu prostředí, aktuálních potravních potřebách či nabídce květních zdrojů. Z evolučního pohledu je pak podoba sítě vztahů mezi rostlinami a opylovači určena tím, jak se druhy na sebe vzájemně...Associations between flowers and pollinators are responsible for reproduction of majority of plant species as well as food supply for substantial part of animal diversity on the Earth. Until recently, the studies on plant-pollinator relationship were focused predominantly on pollination of particular plant species, with only little or no accent on community perspective. In recent decades, however, pollination ecology shifted its focus rather to community context by introducing so called pollination networks. This approach allows us to view the ubiquity and complexity of the interactions between plants and their pollinators and it opened up many new opportunities to study the pollination from animal perspective or to access spatio-temporal variability in the interactions. However, we still have only limited insight into the processes driving the structure and dynamics of such networks. The assembly of plants, pollinators and their interactions are driven by various ecological as well as evolutionary processes. From the ecological point of view, species co-occurrence in time and space may affect the interactions, or species flexibility for various community contexts providing different food sources may play role. In the evolutionary perspective, species may have various co-adaptations due to their...Katedra zoologieDepartment of ZoologyPřírodovědecká fakultaFaculty of Scienc

Ekologické a evoluční procesy určující strukturu sítí rostlin a opylovačů

Associations between flowers and pollinators are responsible for reproduction of majority of plant species as well as food supply for substantial part of animal diversity on the Earth. Until recently, the studies on plant-pollinator relationship were focused predominantly on pollination of particular plant species, with only little or no accent on community perspective. In recent decades, however, pollination ecology shifted its focus rather to community context by introducing so called pollination networks. This approach allows us to view the ubiquity and complexity of the interactions between plants and their pollinators and it opened up many new opportunities to study the pollination from animal perspective or to access spatio-temporal variability in the interactions. However, we still have only limited insight into the processes driving the structure and dynamics of such networks. The assembly of plants, pollinators and their interactions are driven by various ecological as well as evolutionary processes. From the ecological point of view, species co-occurrence in time and space may affect the interactions, or species flexibility for various community contexts providing different food sources may play role. In the evolutionary perspective, species may have various co-adaptations due to their...Abtrakt Rozmnožování většiny druhů rostlin a potrava značné části diverzity živočichů na této planetě přímo závisí na vztazích mezi květy a opylovači. Donedávna se však převážná většina výzkumu opylování zaměřovala pouze na studium opylování konkrétních rostlin a jen málo pozornosti bylo věnováno celým společenstvům rostlin i opylovačů. V posledních desetiletích se však zaměření ekologie opylování posunulo díky zavedení konceptu opylovacích sítí. Tento koncept umožnil zabývat se opylováním v kontextu celého společenstva, poukázal na rozmanitost i komplexitu vztahů mezi rostlinami a jejich opylovači a otevřel řadu nových možností výzkumu těchto vztahů z pohledu jeho významu pro živočichy nebo z pohledu časové a prostorové dynamiky opylovacích interakcí. Přesto však dosud máme jen matné představy o tom, jaké procesy jsou zodpovědné za strukturu a dynamiku těchto sítí. Podoba opylovací sítě je formována jak ekologickými, tak evolučními procesy. Z ekologického pohledu hraje roli například to, jak se druhy v čase a prostoru potkávají nebo jak si jednotlivé taxony opylovačů vybírají mezi rostlinami v závislosti na kontextu prostředí, aktuálních potravních potřebách či nabídce květních zdrojů. Z evolučního pohledu je pak podoba sítě vztahů mezi rostlinami a opylovači určena tím, jak se druhy na sebe vzájemně...Katedra zoologieDepartment of ZoologyFaculty of SciencePřírodovědecká fakult

Spatial Variability in Pollination Networks

Systém vztahů mezi rostlinami a jejich opylovači lze znázornit jako tzv. opylovací sít'. Opylovací sít' umožňuje nahlížet na společenstvo rostlin a opylovačů jako na jeden celek, a všímat si tak jeho uspořádání. Opylovací sítě také poskytují jedinečnou možnost porovnávat mezi sebou ekosystémy z různých oblastí a hledat souvislosti mezi biotickými interakcemi probíhajícími ve společenstvech a biodiverzitou. Jak popisu struktur opylovacích sítí, tak studiu geografických odlišností mezi nimi byla v posledních letech věnována velká pozornost. Dosud zjištěné výsledky jsou však založeny na starších datech, která nebyla k tomuto účelu určena, a nebyla tak zaznamenávána jednotnou metodou. Kvůli tomu jsou jednotlivé sítě těžko interpretovatelné a vzájemně porovnatelné. Moje práce se věnuje především metodice studia opylovacích sítí. Na základě metaanalýzy dříve publikovaných dat a na základě dat ze čtyřletého studia systému rostlin a opylovačů jedné louky poukazuji na některé technické nedostatky dosavadních dat používaných v současných makroeko- logických studiích. Tyto technické nedostatky mohou být zodpovědné za některé ze zákonitostí dokumentovaných v dřívějších studiích věnovaných...Plant-pollinator interaction assembly can be represented as so called pollination network. Using these networks, assembly of plant-pollinator communities and geographic patterns in pollination networks can be studied. During last years, a great progress in describing patterns in structure of plant-pollinator interaction webs and in describing their spatial variability was made. However, these results are mostly based on data from previous studies, which are not seamlessly comparable due to their nonuniformity. My thesis aims at the methodological concepts of study on pollination networks. Based on meta- analysis of previously published data and on data from four years detailed study of plant-pollination system from one locality, I show several methodological problems caused by dissimilarities in sam- pling method of current pollination-network data. These dissimilarities could be responsible for some observed patterns in the assembly of pollination networks. Thus, I propose a uniform method for observing pollination networks suitable for macroecolo- gical meta-analyses (pollination network samples). I tested this method in the field and I described 49 pollination networks from the central and eastern Europe by using such method. In these ne- tworks, no nonrandom structure character such as...Department of ZoologyKatedra zoologiePřírodovědecká fakultaFaculty of Scienc

Vertical stratification of plant–pollinator interactions in a temperate grassland

Visitation of plants by different pollinators depends on individual plant traits, spatial context, and other factors. A neglected aspect of small-scale variation of plant–pollinator interactions is the role of vertical position of flowers. We conducted a series of experiments to study vertical stratification of plant–pollinator interactions in a dry grassland. We observed flower visitors on cut inflorescences of Centaurea scabiosa and Inula salicina placed at different heights above ground in two types of surrounding vegetation: short and tall. Even at such a small-scale, we detected significant shift in total visitation rate of inflorescences in response to their vertical position. In short vegetation, inflorescences close to the ground were visited more frequently, while in tall vegetation, inflorescences placed higher received more visits. Moreover, we found major differences in the composition of the pollinator community on flowers at different heights. In a second experiment, we measured flower visitation rate in inflorescences of Salvia verticillata of variable height. Total flower visitation rate increased markedly with inflorescence height in this case. Data on seed set of individual plants provide evidence for a corresponding positive pollinator-mediated selection on increased inflorescence height. Overall, our results demonstrate strong vertical stratification of plant–pollinator interactions at the scale of mere decimetres. This may have important ecological as well as evolutionary implications

Flower visitation by hoverflies (Diptera: Syrphidae) in a temperate plant-pollinator network

Hoverflies (Diptera: Syrphidae) are among the most important pollinators, although they attract less attention than bees. They are usually thought to be rather opportunistic flower visitors, although previous studied demonstrated that they show colour preferences and their nectar feeding is affected by morphological constraints related to flower morphology. Despite the growing appreciation of hoverflies and other non-bee insects as pollinators, there is a lack of community-wide studies of flower visitation by syrphids. The aim of this paper is to provide a detailed analysis of flower visitation patterns in a species rich community of syrphids in a Central European grassland and to evaluate how species traits shape the structure of the plant-hoverfly flower visitation network. We found that different species varied in the level of specialisation, and while some species visited a similar spectre of flowers, others partitioned resources more strongly. There was a consistent difference in both specialisation and flower preferences between three syrphid subfamilies. Eristalinae and Pipizinae were more specialised than Syrphinae. Trait-based analyses showed that relative flower visitation (i) increased with plant height, but most strongly in Eristalinae; (ii) increased with inflorescence size in small species from all three subfamilies, but was independent of inflorescence size in large species of Eristalinae and Syrphinae; and (iii) depended on flower colour, but in a subfamily-specific way. Eristalinae showed the strongest flower colour preferences for white flowers, Pipizinae visited mostly white and yellow flowers, while Syrphinae were less affected by flower colour. Exploration of the structure of the plant-hoverfly flower visitation network showed that the network was both modular and nested. We also found that there were almost no differences in specialisation and relative visitation frequency between males and females. Overall, we showed that flower visitation in syrphids was affected by phylogenetic relatedness, body size of syrphids and several plant traits

Ecology of pollination networks

In communities, plants and pollinators are organized into complex network of relations. Description of structure in this network can contribute to understanding of community dynamics and persistence of biodiversity. Better understanding of patterns in assemblages of plants and pollinators may also help in their protection. The aim of this work is to review recent methodological principles in the pollination network analyses and to show potential problems in concept of ecological networks. Graph theory is breefly summarized and applied to the description of pollination networks. As an example, results on comparison of communities from different geographical sites are given

Ecological and Evolutionary Processes Driving the Structure of Plant-Pollinator Networks

Associations between flowers and pollinators are responsible for reproduction of majority of plant species as well as food supply for substantial part of animal diversity on the Earth. Until recently, the studies on plant-pollinator relationship were focused predominantly on pollination of particular plant species, with only little or no accent on community perspective. In recent decades, however, pollination ecology shifted its focus rather to community context by introducing so called pollination networks. This approach allows us to view the ubiquity and complexity of the interactions between plants and their pollinators and it opened up many new opportunities to study the pollination from animal perspective or to access spatio-temporal variability in the interactions. However, we still have only limited insight into the processes driving the structure and dynamics of such networks. The assembly of plants, pollinators and their interactions are driven by various ecological as well as evolutionary processes. From the ecological point of view, species co-occurrence in time and space may affect the interactions, or species flexibility for various community contexts providing different food sources may play role. In the evolutionary perspective, species may have various co-adaptations due to their..

Ecology of pollination networks

In communities, plants and pollinators are organized into complex network of relations. Description of structure in this network can contribute to understanding of community dynamics and persistence of biodiversity. Better understanding of patterns in assemblages of plants and pollinators may also help in their protection. The aim of this work is to review recent methodological principles in the pollination network analyses and to show potential problems in concept of ecological networks. Graph theory is breefly summarized and applied to the description of pollination networks. As an example, results on comparison of communities from different geographical sites are given

Spatial Variability in Pollination Networks

Plant-pollinator interaction assembly can be represented as so called pollination network. Using these networks, assembly of plant-pollinator communities and geographic patterns in pollination networks can be studied. During last years, a great progress in describing patterns in structure of plant-pollinator interaction webs and in describing their spatial variability was made. However, these results are mostly based on data from previous studies, which are not seamlessly comparable due to their nonuniformity. My thesis aims at the methodological concepts of study on pollination networks. Based on meta- analysis of previously published data and on data from four years detailed study of plant-pollination system from one locality, I show several methodological problems caused by dissimilarities in sam- pling method of current pollination-network data. These dissimilarities could be responsible for some observed patterns in the assembly of pollination networks. Thus, I propose a uniform method for observing pollination networks suitable for macroecolo- gical meta-analyses (pollination network samples). I tested this method in the field and I described 49 pollination networks from the central and eastern Europe by using such method. In these ne- tworks, no nonrandom structure character such as..

Ecological and Evolutionary Processes Driving the Structure of Plant-Pollinator Networks

Associations between flowers and pollinators are responsible for reproduction of majority of plant species as well as food supply for substantial part of animal diversity on the Earth. Until recently, the studies on plant-pollinator relationship were focused predominantly on pollination of particular plant species, with only little or no accent on community perspective. In recent decades, however, pollination ecology shifted its focus rather to community context by introducing so called pollination networks. This approach allows us to view the ubiquity and complexity of the interactions between plants and their pollinators and it opened up many new opportunities to study the pollination from animal perspective or to access spatio-temporal variability in the interactions. However, we still have only limited insight into the processes driving the structure and dynamics of such networks. The assembly of plants, pollinators and their interactions are driven by various ecological as well as evolutionary processes. From the ecological point of view, species co-occurrence in time and space may affect the interactions, or species flexibility for various community contexts providing different food sources may play role. In the evolutionary perspective, species may have various co-adaptations due to their..