OPUS 4 | Institut für Ökologie, Evolution und Diversität

The taxonomist - an endangered race : a practical proposal for its survival (2011)

Heike Wägele Annette Klussmann-Kolb Michael Kuhlmann Gerhard Haszprunar David Lindberg André Koch Johann Wolfgang Wägele

Background: Taxonomy or biological systematics is the basic scientific discipline of biology, postulating hypotheses of identity and relationships, on which all other natural sciences dealing with organisms relies. However, the scientific contributions of taxonomists have been largely neglected when using species names in scientific publications by not citing the authority on which they are based. Discussion: Consequences of this neglect is reduced recognition of the importance of taxonomy, which in turn results in diminished funding, lower interest from journals in publishing taxonomic research, and a reduced number of young scientists entering the field. This has lead to the so-called taxonomic impediment at a time when biodiversity studies are of critical importance. Here we emphasize a practical and obvious solution to this dilemma. We propose that whenever a species name is used, the author(s) of the species hypothesis be included and the original literature source cited, including taxonomic revisions and identification literature - nothing more than what is done for every other hypothesis or assumption included in a scientific publication. In addition, we postulate that journals primarily publishing taxonomic studies should be indexed in ISISM. Summary: The proposal outlined above would make visible the true contribution of taxonomists within the scientific community, and would provide a more accurate assessment for funding agencies impact and importance of taxonomy, and help in the recruitment of young scientists into the field, thus helping to alleviate the taxonomic impediment. In addition, it would also make much of the biological literature more robust by reducing or alleviating taxonomic uncertainty. Keywords: Taxonomy crisis; taxonomic impediment; impact factor; original species description; citation index; systematics

Transcriptomic evidence that longevity of acquired plastids in the photosynthetic slugs Elysia timida and Plakobrachus ocellatus does not entail lateral transfer of algal nuclear genes (2010)

Heike Wägele Oliver Deusch Katharina Händeler Rainer Martin Valerie Schmitt Gregor Christa Britta Pinzger Sven B. Gould Tal Dagan Annette Klussmann-Kolb William Martin

Sacoglossan sea slugs are unique in the animal kingdom in that they sequester and maintain active plastids that they acquire from the siphonaceous algae upon which they feed, making the animals photosynthetic. While most sacoglossan species digest their freshly ingested plastids within hours, four species from the family Plakobranchidae retain their stolen plastids (kleptoplasts) in a photosynthetically active state on time scales of weeks to months. The molecular basis of plastid maintenance within the cytosol of digestive gland cells in these photosynthetic metazoans is yet unknown, but is widely thought to involve gene transfer from the algal food source to the slugs based upon previous investigations of single genes. Indeed, normal plastid development requires hundreds of nuclear-encoded proteins, with protein turnover in photosystem II in particular known to be rapid under various conditions. Moreover, only algal plastids, not the algal nuclei, are sequestered by the animals during feeding. If algal nuclear genes are transferred to the animal either during feeding or in the germ line, and if they are expressed, then they should be readily detectable with deep-sequencing methods. We have sequenced expressed mRNAs from actively photosynthesizing, starved individuals of two photosynthetic sea slug species, Plakobranchus ocellatus Van Hasselt, 1824 and Elysia timida Risso, 1818. We find that nuclear-encoded, algal-derived genes specific to photosynthetic function are expressed neither in P. ocellatus nor in E. timida. Despite their dramatic plastid longevity, these photosynthetic sacoglossan slugs do not express genes acquired from algal nuclei in order to maintain plastid function.

Evolution of microgastropods (Ellobioidea, Carychiidae): integrating taxonomic, phylogenetic and evolutionary hypotheses (2013)

Alexander M. Weigand Adrienne Jochum Rajko Slapnik Jan Schnitzler Eugenia Zarza Annette Klussmann-Kolb

BACKGROUND: Current biodiversity patterns are considered largely the result of past climatic and tectonic changes. In an integrative approach, we combine taxonomic and phylogenetic hypotheses to analyze temporal and geographic diversification of epigean (Carychium) and subterranean (Zospeum) evolutionary lineages in Carychiidae (Eupulmonata, Ellobioidea). We explicitly test three hypotheses: 1) morphospecies encompass unrecognized evolutionary lineages, 2) limited dispersal results in a close genetic relationship of geographical proximally distributed taxa and 3) major climatic and tectonic events had an impact on lineage diversification within Carychiidae. RESULTS: Initial morphospecies assignments were investigated by different molecular delimitation approaches (threshold, ABGD, GMYC and SP). Despite a conservative delimitation strategy, carychiid morphospecies comprise a great number of unrecognized evolutionary lineages. We attribute this phenomenon to historic underestimation of morphological stasis and phenotypic variability amongst lineages. The first molecular phylogenetic hypothesis for the Carychiidae (based on COI, 16S and H3) reveals Carychium and Zospeum to be reciprocally monophyletic. Geographical proximally distributed lineages are often closely related. The temporal diversification of Carychiidae is best described by a constant rate model of diversification. The evolution of Carychiidae is characterized by relatively few (long distance) colonization events. We find support for an Asian origin of Carychium. Zospeum may have arrived in Europe before extant members of Carychium. Distantly related Carychium clades inhabit a wide spectrum of the available bioclimatic niche and demonstrate considerable niche overlap. CONCLUSIONS: Carychiid taxonomy is in dire need of revision. An inferred wide distribution and variable phenotype suggest underestimated diversity in Zospeum. Several Carychium morphospecies are results of past taxonomic lumping. By collecting populations at their type locality, molecular investigations are able to link historic morphospecies assignments to their respective evolutionary lineage. We propose that rare founder populations initially colonized a continent or cave system. Subsequent passive dispersal into adjacent areas led to in situ pan-continental or mountain range diversifications. Major environmental changes did not influence carychiid diversification. However, certain molecular delimitation methods indicated a recent decrease in diversification rate. We attribute this decrease to protracted speciation.

Endocrine disruptors in bottled mineral water : total estrogenic burden and migration from plastic bottles (2009)

Martin Wagner Jörg Oehlmann

Background, aim, and scope Food consumption is an important route of human exposure to endocrine-disrupting chemicals. So far, this has been demonstrated by exposure modeling or analytical identification of single substances in foodstuff (e.g., phthalates) and human body fluids (e.g., urine and blood). Since the research in this field is focused on few chemicals (and thus missing mixture effects), the overall contamination of edibles with xenohormones is largely unknown. The aim of this study was to assess the integrated estrogenic burden of bottled mineral water as model foodstuff and to characterize the potential sources of the estrogenic contamination. Materials, methods, and results In the present study, we analyzed commercially available mineral water in an in vitro system with the human estrogen receptor alpha and detected estrogenic contamination in 60% of all samples with a maximum activity equivalent to 75.2 ng/l of the natural sex hormone 17beta-estradiol. Furthermore, breeding of the molluskan model Potamopyrgus antipodarum in water bottles made of glass and plastic [polyethylene terephthalate (PET)] resulted in an increased reproductive output of snails cultured in PET bottles. This provides first evidence that substances leaching from plastic food packaging materials act as functional estrogens in vivo. Discussion and conclusions Our results demonstrate a widespread contamination of mineral water with xenoestrogens that partly originates from compounds leaching from the plastic packaging material. These substances possess potent estrogenic activity in vivo in a molluskan sentinel. Overall, the results indicate that a broader range of foodstuff may be contaminated with endocrine disruptors when packed in plastics. Keywords Endocrine disrupting chemicals - Estradiol equivalents - Human exposure - In vitro effects - In vivo effects - Mineral water - Plastic bottles - Plastic packaging - Polyethylene terephthalate - Potamopyrgus antipodarum - Yeast estrogen screen - Xenoestrogens

Molecular phylogeny of the acanthocephala (class palaeacanthocephala) with a paraphyletic assemblage of the orders polymorphida and echinorhynchida (2011)

Lisa Verweyen Sven Klimpel Harry W. Palm

Acanthocephalans are attractive candidates as model organisms for studying the ecology and co-evolutionary history of parasitic life cycles in the marine ecosystem. Adding to earlier molecular analyses of this taxon, a total of 36 acanthocephalans belonging to the classes Archiacanthocephala (3 species), Eoacanthocephala (3 species), Palaeacanthocephala (29 species), Polyacanthocephala (1 species) and Rotifera as outgroup (3 species) were analyzed by using Bayesian Inference and Maximum Likelihood analyses of nuclear 18S rDNA sequence. This data set included three re-collected and six newly collected taxa, Bolbosoma vasculosum from Lepturacanthus savala, Filisoma rizalinum from Scatophagus argus, Rhadinorhynchus pristis from Gempylus serpens, R. lintoni from Selar crumenophthalmus, Serrasentis sagittifer from Johnius coitor, and Southwellina hispida from Epinephelus coioides, representing 5 new host and 3 new locality records. The resulting trees suggest a paraphyletic arrangement of the Echinorhynchida and Polymorphida inside the Palaeacanthocephala. This questions the placement of the genera Serrasentis and Gorgorhynchoides within the Echinorhynchida and not the Polymorphida, necessitating further insights into the systematic position of these taxa based on morphology.

Entwicklung einer GIS-gestützten Standardmethode (GisMap) zur Untersuchung der pflanzlichen Artenvielfalt in der Normallandschaft (2005)

Michael Uebeler

In der vorliegenden Arbeit wird ein neu entwickeltes Erfassungsinstrument für die pflanzliche Artenvielfalt in der Normallandschaft vorgestellt, dass den Namen GISMap trägt. Die standardisierte Vorgehensweise und eine große Reproduzierbarkeit des Aufnahmeverfahrens sind wichtige Eigenschaften der Methode. GISMap basiert auf der GIS-gestützten Auswertung der Landschaftsstruktur, die in Form eines digitalen Landschaftsmodells (DLM) zugrunde gelegt wird. Im Zentrum der Methode steht ein im Rahmen der Arbeit entwickelter Algorithmus, der eine zufallsgesteuerte Festlegung von Aufnahmeflächen in der zu untersuchenden Landschaft vornimmt und sich dabei an den Ökotonen orientiert, die sich zwischen zwei benachbarten Landschaftselementen ausbilden. Ökotone sind als Übergangsbiotope häufig sehr reich an Strukturen und können daher eine große Artenvielfalt aufweisen. GIS-Map macht sich diese ökologische Gegebenheit zunutze, um auf möglichst kleinem Raum eine große Artenzahl zu erfassen. Die von GISMap errechneten Aufnahmeflächenkoordinaten wurden mit Hilfe eines GPS-Empfängers im Gelände lokalisiert und einer floristischen Untersuchung unterzogen. Als geeignete Aufnahmeflächengröße erwies sich dabei ein Kreis mit einer Fläche von 700 m². Die Flächen wurden mit Magneten markiert, um sie zur Dauerbeobachtung der Flora nutzen zu können. In dem 33 km² großen Untersuchungsgebiet, das im östlichen Bereich des Taunus liegt, wurden insgesamt 141 Aufnahmeflächen für 16 64tel-MTB-Rasterfelder angelegt. Um den mit der Methode zu erzielenden Erfassungsgrad abschätzen zu können, wurden umfangreiche Vergleichsuntersuchungen durchgeführt, die auch eine Auswertung vorliegender Literaturquellen mit einschlossen. In den 16 untersuchten Rasterfeldern konnten durchschnittlich 73 % der insgesamt vorkommenden Arten mit der Methode erfasst werden. Dazu müssen nur 0,3 % der Fläche tatsächlich einer floristischen Untersuchung unterzogen werden. Alle kartierten Arten erhalten dabei eine punktgenaue Koordinate. Die Methode wurde als Basisinstrument konzipiert und sollte mit bereits vorliegenden Fachdaten kombiniert werden, um die Erfassung der Farn- und Samenpflanzen eines Gebietes zu vervollständigen. Diskutiert wird der Einsatz im Rahmen eines Landschaftsinformationssystems (LIS). Durch eine Ergänzung der mit GISMap erhobenen Daten mit anderen vegetationskundlichen Daten aus dem Untersuchungsgebiet konnte der Erfassungs-grad von 73 % auf 85 % gesteigert werden. Im Rahmen der Arbeit werden zahlreiche Möglichkeiten der technischen Weiterentwicklung dargestellt, die zu einer Optimierung der Methode beitragen können. Ausgehend von den Daten des digitalen Landschaftsmodells wurden zur Beschreibung der landschaftlichen Struktur des Untersuchungsgebietes verschiedene Landschaftsstrukturmaße berechnet, wie sie in der modernen landschaftsökologischen Forschung mittlerweile häufig zum Einsatz kommen. Diese wurden mit den erfassten Sippenzahlen korreliert, um Zusammenhänge zwischen der Landschaftsstruktur und dem auftretenden floristischen Ar-tenreichtum darzustellen. Dabei wurde auch der Fragestellung nachgegangen, ob auf der Basis von Maßzahlen für die Landschaftsstruktur Prognosen über die zu erwartende pflanzli-che Artenvielfalt getroffen werden können. Ein weiterer Aspekt der Untersuchungen bestand in der Nutzung des entstandenen Aufnahmeflächennetzes zur langfristigen Beobachtung von Veränderungen der Vegetation des betrachteten Landschaftsausschnittes. Anhand der Frequenzen in den Aufnahmeflächen kann mit GISMap ein langfristiges Monitoring auf der Ebene einzelner Arten durchgeführt werden. Dies wird u. a. in Hinblick auf die im Untersuchungsgebiet auftretenden Neophyten diskutiert. Als Möglichkeit zum Monitoring der gesamten Vegetation wurde der Ansatz verfolgt, die Verteilung der kartierten Arten auf 24 häufig in der Literatur beschriebene Pflanzenformationen festzustellen. Es wird vorgeschlagen, eine langfristige Beobachtung dieses Verteilungsmusters vorzunehmen, um einen Aufschluss über ökologische Veränderungen der Landschaft anhand der Vegetation zu erhalten. Weitere Auswertungen der gesammelten floristischen Daten beziehen sich auf ihre Eignung zum Monitoring von klimatischen Veränderungen. Die Berechnung mittlerer Temperaturzahlen für 6 Höhenstufen erwies sich dabei als ungeeignet, da ihre Unterschiede zwischen den Höhenstufen nicht statistisch abzusichern waren. Darüber hinaus wurde die Verteilung von Kühlezeigern in dem entstandenen Aufnahmeflächennetz für die verschiedenen Höhenstufen untersucht. Hinweise zu ihrer Eignung als Indikatoren für klimatische Veränderungen werden diskutiert.

Utility of arsenic-treated bird skins for DNA extraction (2011)

Till Töpfer Anita Gamauf Elisabeth Haring

Background: Natural history museums receive a rapidly growing number of requests for tissue samples from preserved specimens for DNA-based studies. Traditionally, dried vertebrate specimens were treated with arsenic because of its toxicity and insect-repellent effect. Arsenic has negative effects on in vivo DNA repair enzymes and consequently may inhibit PCR performance. In bird collections, foot pad samples are often requested since the feet were not regularly treated with arsenic and because they are assumed to provide substantial amounts of DNA. However, the actual influence of arsenic on DNA analyses has never been tested. Findings: PCR success of both foot pad and body skin samples was significantly lower in arsenic-treated samples. In general, foot pads performed better than body skin samples. Moreover, PCR success depends on collection date in which younger samples yielded better results. While the addition of arsenic solution to the PCR mixture had a clear negative effect on PCR performance after the threshold of 5.4 μg/μl, such high doses of arsenic are highly unlikely to occur in dried zoological specimens. Conclusions: While lower PCR success in older samples might be due to age effects and/or DNA damage through arsenic treatment, our results show no inhibiting effect on DNA polymerase. We assume that DNA degradation proceeds more rapidly in thin tissue layers with low cell numbers that are susceptible to external abiotic influences. In contrast, in thicker parts of a specimen, such as foot pads, the outermost horny skin may act as an additional barrier. Since foot pads often performed better than body skin samples, the intention to preserve morphologically important structures of a specimen still conflicts with the aim to obtain optimal PCR success. Thus, body skin samples from recently collected specimens should be considered as alternative sources of DNA.

The contribution of vegetation and landscape configuration for predicting environmental change impacts on Iberian birds (2011)

Maria Triviño Wilfried Thuiller Mar Cabeza Thomas Hickler Miguel B. Araújo

Although climate is known to be one of the key factors determining animal species distributions amongst others, projections of global change impacts on their distributions often rely on bioclimatic envelope models. Vegetation structure and landscape configuration are also key determinants of distributions, but they are rarely considered in such assessments. We explore the consequences of using simulated vegetation structure and composition as well as its associated landscape configuration in models projecting global change effects on Iberian bird species distributions. Both present-day and future distributions were modelled for 168 bird species using two ensemble forecasting methods: Random Forests (RF) and Boosted Regression Trees (BRT). For each species, several models were created, differing in the predictor variables used (climate, vegetation, and landscape configuration). Discrimination ability of each model in the present-day was then tested with four commonly used evaluation methods (AUC, TSS, specificity and sensitivity). The different sets of predictor variables yielded similar spatial patterns for well-modelled species, but the future projections diverged for poorly-modelled species. Models using all predictor variables were not significantly better than models fitted with climate variables alone for ca. 50% of the cases. Moreover, models fitted with climate data were always better than models fitted with landscape configuration variables, and vegetation variables were found to correlate with bird species distributions in 26–40% of the cases with BRT, and in 1–18% of the cases with RF. We conclude that improvements from including vegetation and its landscape configuration variables in comparison with climate only variables might not always be as great as expected for future projections of Iberian bird species.

Impact of protected areas and land use on regeneration of Acacia woodland’s in Eastern Burkina Faso (2008)

Salifou Traoré Oumar Kaboré Jeanne Millogo Rasolodimbi Lamourdia Thiombiano Sita Guinko

Regeneration success, persistence strategies (seedlings vs. coppicing), and population trend of Acacia spp. were tested under two land-use regimes in eastern Burkina Faso: (i) protected areas shielded to livestock grazing pressure, to logging, and using early annual fire as a management system; (ii) areas with high human impact (heavily and extensive livestock grazing, harvesting for wood and for medicinal plants). Generally, a good regeneration rate of Acacia species was observed in protected areas and a poor regeneration rate in areas with high human impact. Nevertheless, some species affiliated to the subgenus Aculeiferum as A. dudgeoni and A. polyacantha showed a good regeneration under both land use regimes. Juvenile plants less than 25 cm height of A. dudgeoni and A. gourmaensis increased by 116 to 50 % in areas with human impact as compared to their populations in protected areas. With SCD slopes varying from –0.40 to -0.70, the protected Acacia woodland displayed a stable population structure due to abundance of recruitment, and coppicing persistence (more common in the subgenus Aculeiferum) favoured by early annual fire. Consequently, the protected areas are favourable for Acacia woodland regeneration. Conversely, SCD slopes are positive or close to zero in areas of anthropogenic regime and showed a declining population, especially more marked with the subgenus Acacia due to permanent seed and seedling removal by livestock grazing. Nevertheless, the number of seedlings of some species was higher in areas under human pressure than in protected areas, especially for the subgenus Aculeiferum, improving the genetic variability and thus the long-term maintenance of the population. Key words: Acacia, early fire, land use, sudano-sahelien zone

Eine Erde voller Arten : Darwins Vermächtnis in der heutigen Evolutionsbiologie (2008)

Bruno Streit Markus Pfenninger Klaus Schwenk

Institut für Ökologie, Evolution und Diversität

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