Georg Zizka

Georg Zizka
Goethe-Universität Frankfurt am Main and Senckenberg Research Institute Frankfurt · Botany and Molecular Evolution

Prof. Dr.

About

334
Publications
94,286
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3,875
Citations
Additional affiliations
November 1995 - present
Senckenberg Research Institute and Goethe University
July 1987 - October 1995
Palmengarten of the City of Frankfurt
January 1982 - June 1987
Senckenberg Research Institute and Goethe University

Publications

Publications (334)
Article
The continuous refinement of the morphological, anatomical, and molecular studies on the genera of the “Cryptanthoid complex”, mainly considering the recently discovered outlier species, gave rise to new interpretations of species relationships. It reinforced the monophyly of the groups, and allowed the recognition of the new monotypic genus Siquei...
Article
Full-text available
Ochnaceae is a pantropical family with multiple transoceanic disjunctions at deep and shallow levels. Earlier attempts to unravel the processes that led to such biogeographic patterns suffered from insufficient phylogenetic resolution and unclear delimitation of some of the genera. In the present study, we estimated divergence time and ancestral ra...
Article
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Advances in high-throughput DNA sequencing are allowing faster and more affordable generation of molecular phylogenetic trees for many organisms. However, resolving relationships at species level is still challenging, particularly for taxonomically difficult groups. Until recently, the classification of Ochna had been based only on morphological da...
Article
Advances in high-throughput DNA sequencing are allowing faster and more affordable generation of molecular phylogenetic trees for many organisms. However, resolving relationships at species level is still challenging, particularly for taxonomically difficult groups. Until recently, the classification of Ochna had been based only on morphological da...
Article
Full-text available
Premise: Both universal and family-specific targeted sequencing probe kits are becoming widely used for reconstruction of phylogenetic relationships in angiosperms. Within the pantropical Ochnaceae, we show that with careful data filtering, universal kits are equally as capable in resolving intergeneric relationships as custom probe kits. Furtherm...
Article
Generic status for the Amazonian Hylaeaicum is proposed within the Aechmea alliance, excluding it from the “Nidularioid complex” in general and from Neoregelia in particular. The monophyly of this new genus is supported by molecular phylogenetic analyses. The taxonomic circumscription of Hylaeaicum is based on the combination of geographical range...
Article
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Der Botanische Garten an der Siesmayerstraße in Frankfurt ist seit dem 1.1.2012 Teil des städtischen Palmengartens. Die Ge- schichte eines Botanischen Gartens in Frankfurt reicht bis ins Jahr 1763 zurück, als Johann Christian Senckenberg die Dr. Senckenbergische Stiftung begründete, die dann Erbauerin und über 150 Jahre Trägerin des ersten Frankfur...
Article
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Die kostenlose App „iNaturalist“ bringt interessierte Laien und Experten zusammen. Die App schafft einen niedrigschwelligen Zugang zur Biodiversitätserfassung und Pflanzenbestimmung, Experten sorgen ehrenamtlich für Qualitätssicherung. Auf verschiedenen räumlichen Ebenen wurden Projekte initiiert, z.B. durch die BVNH e.V., das Forschungsinstitut Se...
Article
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Plastid DNA sequence data have been traditionally widely used in plant phylogenetics because of the high copy number of plastids, their uniparental inheritance, and the blend of coding and non-coding regions with divergent substitution rates that allow the reconstruction of phylogenetic relationships at different taxonomic ranks. In the present stu...
Article
Full-text available
An amendment to this paper has been published and can be accessed via the original article.
Article
Aim We investigate the evolutionary mechanisms that allow morphologically convergent lineages to share the same geographical space. We compared the evolutionary events that occurred along the diversification of Karawata and Aechmea subgen. Chevaliera in the Atlantic Forest by (a) verifying whether the climatic niches and habitats of Karawata and Ch...
Article
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The subfamily Bromelioideae is one of the most diverse groups among the neotropical Bromeliaceae. Previously, key innovations have been identified which account for the extraordinary radiation and species richness of this subfamily, especially in the so-called core Bromelioideae. However, in order to extend our understanding of the evolutionary mec...
Article
Ochagavia (four species) and Fascicularia (one species) form a well-supported clade of the early-diverging Bromelioideae. The two genera are morphologically similar, but they can be easily discerned on the basis of generative characters. Besides the species distributed on the Chilean mainland, the group includes O. elegans, endemic to the Robinson...
Article
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We describe the chromosome numbers and genome sizes of species of the cryptanthoid complex of Bromeliaceae in a phylogenetic framework and their relationship with habitat preferences. The 2C DNA contents varied 2.13-fold among species, ranging from 0.76 to 1.66 pg. A significant difference in DNA content was found among Cryptanthus, Hoplocryptanthu...
Article
Full-text available
Background The angiosperm family Bromeliaceae comprises over 3.500 species characterized by exceptionally high morphological and ecological diversity, but a very low genetic variation. In many genera, plants are vegetatively very similar which makes determination of non flowering bromeliads difficult. This is particularly problematic with living co...
Article
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Plants, fungi and algae are important components of global biodiversity and are fundamental to all ecosystems. They are the basis for human well-being, providing food, materials and medicines. Specimens of all three groups of organisms are accommodated in herbaria, where they are commonly referred to as botanical specimens. The large number of spec...
Article
Androlepis najarroi (Bromelioideae, Bromeliaceae), a third dioecious species identified in the subfamily, is proposed as new from the Chiapas Highlands and Veracruzan biogeographical provinces, southern Megamexico. The novelty is superficially similar to Aechmea lueddemanniana but features characteristics of Androlepis, such as unisexual flowers an...
Article
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Aim To provide distribution information and preliminary conservation assessments for all species of the pineapple family (Bromeliaceae), one of the most diverse and ecologically important plant groups of the American tropics—a global biodiversity hotspot. Furthermore, we aim to analyse patterns of diversity, endemism and the conservation status of...
Article
We describe the chromosome numbers and genome sizes of species of the cryptanthoid complex of Bromeliaceae in a phylogenetic framework and their relationship with habitat preferences. The 2C DNA contents varied 2.13-fold among species, ranging from 0.76 to 1.66 pg. A significant difference in DNA content was found among Cryptanthus, Hoplocryptanthu...
Article
Um die Vielfalt der Tiere und Pilze in den drei Frankfurter Botanischen Gärten zu dokumentieren, wurde ein Bürgerwissenschaftsprojekt auf der iNaturalist-Plattform eingerichtet. Diese wird hier vorgestellt und ein Überblick zu den bereits vorhandenen Beobachtungen gegeben.
Article
The terrestrial bromeliad Fosterella rusbyi is endemic to the Bolivian Andes, where it mainly grows on steep, exposed slopes along roadsides and riverbeds in the seasonally dry tropical forest (SDTF) and the mesic montane forest (Yungas) biomes. We hypothesize that allopatric speciation may have been a main driver of diversification in Fosterella s...
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The northern Chilean Atacama Desert is among those regions on Earth where life exists at its dry limits. There is almost zero rainfall in its core zone, and the only source of water is a spatio-temporally complex fog system along the Pacific coast, which is reaching far into the hyperarid mainland. Hardly any vascular plants grow in these areas, an...
Article
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To document the diversity of animals and mushrooms in the three Frankfurt Botanic Gardens, a citizen science project has been set up on the iNaturalist platform. This is presented here with an overview of the already existing observations.
Article
A better understanding of the phylogenetics of Aechmea subgenus Chevaliera is hampered by the limited taxonomic sampling in molecular studies of Bromelioideae. To test the monophyly of Aechmea subgenus Chevaliera, we conducted a molecular phylogenetic study using three DNA regions (ETS, matK and phyC) and a reconstruction of ancestral states of mor...
Article
A better understanding of the phylogenetics of Aechmea subgenus Chevaliera is hampered by the limited taxonomic sampling in molecular studies of Bromelioideae. To test the monophyly of Aechmea subgenus Chevaliera, we conducted a molecular phylogenetic study using three DNA regions (ETS, matK and phyC) and a reconstruction of ancestral states of mor...
Article
Full-text available
Since the first description of the genus in 1754, the taxonomy of Ananas underwent many fundamental changes and it is still the subject of a vivid debate. We present a phylogeny comprising all seven known Ananas taxa, Pseudananas sagenarius as well as closely related members of Bromelioideae (Aechmea subg. Chevaliera) based on three nuclear markers...
Article
Knowledge of spatial patterns of biological diversity is fundamental for ecological and biogeographical analyses and for priority setting in nature conservation, particularly in West Africa where the existing high biodiversity is increasingly threatened by human activities. The maximum entropy approach was used to model the geographic distribution...
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Full-text available
Background Leaf venation traits are important for many research fields such as systematics and evolutionary biology, plant physiology, climate change, and paleoecology. In spite of an increasing demand for vein trait data, studies are often still data-limited because the development of methods that allow rapid generation of large sets of vein data...
Article
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Hexaploid Chenopodium album is common in Frankfurt/Main (Hesse). Plants differ in blooming time, height, branching pattern, leaf shape and inflorescence morphology. Morphologically similar plants often grow together. Characteristics vary independently of each other and it is inappropriate to recognize them as taxonomic units.
Article
Cross-biome data suggest that leaf venation density increases with decreasing moisture availability. If leaf venation traits were related to climatic conditions in such a predictable manner, these traits could serve, for example, as proxies for the reconstruction of past climates from fossil leaf remnants. However, our knowledge on vein–climate rel...
Article
Full-text available
Chromosomal speciation processes gain increasing attention in plant systematics and evolution, and new approaches revealed a high diversity in chromosome numbers even within recognized taxa. Reliable counts linked to known accessions are thus needed yet often hardly available. We present a new online database for chromosome counts and ploidy estima...
Poster
Full-text available
The distribution of polyploidy along a relatively steep Andean elevation gradient was studied using the genus Fosterella. Flow cytometry was used to estimate the ploidy of 22 species sampled throughout the distribution range. Ecological differentiation among ploidy levels was tested by comparing the climatic variables. Ancestral chromosome number r...
Article
The authors provide a new circumscription for genera of the “Cryptanthoid complex” of Bromeliaceae subfam. Bromelioideae, originally composed of Cryptanthus, Lapanthus, Orthophytum, and Sincoraea, on the basis of new or reevaluated ecological, geographical and morphological evidence, as well as molecular phylogenies. A new generic status is propose...
Article
Amazonia arguably harbours the highest plant species diversity of all wet tropical regions on earth. There is increasing evidence that this enormous diversity is the product of a rather long and complex process and not of a single cause. Here, we investigated divergence times and diversification dynamics in the Neotropical Quiinoideae (Malpighiales...
Article
- Background and Aims The distribution of polyploidy along a relatively steep Andean elevation and climatic gradient is studied using the genus Fosterella L.B. Sm. (Bromeliaceae) as a model system. Ecological differentiation of cytotypes and the link of polyploidy with historical biogeographic processes such as dispersal events and range shift are...
Presentation
Full-text available
Presentation of history, latest developments and future plans for ’African Plants - a photo guide’, an online photo database and identification tool for African plants.
Presentation
Full-text available
Presentation of the automated, EOO- and AOO-based threat assessment of Burkina Faso’s flora, as published in Schmidt, Zizka et al. 2017 Phytotaxa
Poster
Full-text available
The West African Vegetation Database is an online platform designed to securely store, edit and manage vegetation plot data from West Africa. An integrated access manage- ment system allows data owners to keep data private, to grant selected users access or to make data sets available to the general public. Data entry is possible online or in a loc...
Poster
Full-text available
Starting with the West African Plant Photo Database in 2008, we developed a photographic guide for the African continent. Instructive photos and multientry determination keys based on 18 easily accessible characters help scientists and laymen to identify African plants. Simultaneously, the photo guide serves as an archive of plant images and, using...
Article
Full-text available
West Africa is a floristically understudied region that is facing severe environmental changes in the 21st century. Basic distribution data and information on the conservation status for most plant species of the region are scarce, and good information only exists for small areas of interest or for key species. This lack of knowledge seriously hamp...
Article
Citizen science. Citizen science is performed on a honorary basis. Citizen scientists (”Citizen Science proper“) have no professional employment in the relevant field of research and differ very much in their educational background, specific knowledge and amount of time dedicated to the subject of research. Today, citizen science has become especia...
Article
Full-text available
Reticulate evolution is considered to be among the main mechanisms of plant evolution, often leading to the establishment of new species. However, complex evolutionary scenarios result in a challenging definition of evolutionary and taxonomic units. In the present study, we aimed to examine the evolutionary origin and revise the species status of C...