oekologie_xs   Meet an Ecology PhD


Below we present a series of brief spotlights on different research talents at our Institute and the issues they investigated in their doctoral studies. Read about how they developed the expertise in their fields and, maybe, take profit of the one or the others lessons learned or critique.

Herbert Wagner

Decrypting a complex of European ant species

Herbert C. Wagner is a myrmecologist and a member of the Molecular Ecology Research group headed by Birgit Schlick-Steiner. In his PhD project, funded by FWF and University of Innsbruck, he aims to delimit species of the last enigmatic ant species complex in Central Europe remained unrevised so far – the cryptic Tetramorium caespitum/impurum complex. The species are “cryptic” in a human point of view, which does mean that myrmecologists were not able to distinguish these species so far, because of being extremely similar in morphology.

Based on a multidisciplinary approach, Herbert revises the taxonomy and aims to understand the evolution of the Tetramorium caespitum/impurum complex. Therefore, his team collected several thousand nest samples from 35 nations in Europe, Anatolia, the Caucasus, and Central Asia. Their investigation is based on integrative taxonomy, i.e., the combination of independent methods using the same biological samples. More than 900 ants were used for traditional morphometric analyses of 32 characters. Qualitative genital-structure investigations of males complement the morphological data. For genetic investigation, they sequenced a mitochondrial gene and scored amplified-fragment-length polymorphisms.

Based on our multidisciplinary dataset, Herbert demonstrates the presence of ten well-separated European species and uses this insight for our taxonomic revision. Also a determination key using discriminant analyses of morphometric data is made; using the new characters, more than 97% of the nest samples can be determined. Hybridization between species is rare. Two species of the complex are newly described.

Mag. Herbert Christian Wagner
University of Innsbruck
Institute of Ecology
Molecular Ecology Research Group

email: Herbert.Wagner@uibk.ac.at

 

Carina Rofner on taking samples

FWF-project: Heterotrophic freshwater bacterial groups and the biogeochemical cycle of phosphorus in mountain lakes

The main aim of my thesis is to understand the role played by heterotrophic freshwater bacteria in the uptake of inorganic and organic phosphorus compounds as well as the strategies used of individual bacterial taxa to cope with low phosphorus concentrations.

Heterotrophic bacteria play a central role in the biogeochemical cycle of elements in aquatic ecosystems. They (re-) cycle dead organic material to biomass and thus, provide energy and nutrients to higher trophic levels (zooplankton, fish). Although phosphorus (P) is a key nutrient limiting bacterial growth in freshwater ecosystems, knowledge on inorganic and organic P utilization by individual bacterial taxa is scarce.

By applying cultivation-independent approaches (uptake of radiolabelled-substrates at the community and taxon-specific level, 16S rDNA sequencing), we gained first insights in the P dynamics of low-productive lakes and identified strategies used by bacterial members to cope with low P concentrations. For instance, it seemed that different bacterial taxa have variable P requirements when related to their growth activity, which means that bacteria differ in their needs for P to maintain growth.

In experiments carried out in a high altitude and latitude lake, we further assessed whether climate-induced changes in plant cover (treeline) and soil chemical composition alter lake bacterial community composition and function. The results obtained in this study are of particular relevance as changes in lake catchments affecting the availability of P in soils, impact bacterial growth rates and thus, the flux of C and P to higher trophic levels.

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Carina Rofner

 
 Georg Niedrist

How to secure food in harsh stream ecosystems?

Georg Niedrist is a PhD-candidate and a member of the group River and Conservation Research headed by Leopold Füreder, which focuses among other topics on running waters in high altitudes and latitudes (www.uibk.ac.at/ecology/forschung/river_conservation_ecology.html.en). Within this thematic framework, Georg’s research concentrates on alpine streams and the benthic invertebrate species, their trophic relationships and potential alterations due to environmental change.  

Glacial retreat leads to considerable hydrological shifts in most alpine streams. While the resulting alterations in the community structures in such habitats have been elaborated deeply within several research activities of Füreder’s group, potential shifts of ecological functions and trophic relationships of benthic invertebrate species remained mostly unknown.

In his current PhD-projects, funded by the Nationalpark Hohe Tauern, the TWF and the D. Swarovski KG, Georg wants to shed light on the trophic strategies and adaptations of the most important secondary producers in alpine streams, which allow the species to persist in these harsh environments. He will simulate the effect of decreasing glacial influence on the characteristics of trophic relationships between predominant consumers (larvae of the dipteran family of Chironomidae) and primary producers in alpine streams. The methodology involves traditional (gut content) and innovative (C and N stable isotopes) analyses with the employment of novel mixing and ecological modelling. Georg combines laboratory work with extensive fieldwork in the great environment of the Nationalpark Hohe Tauern, wherein the project Monitoring Alpine Rivers (PI Leopold Füreder) he is an active researcher since 2009.

Besides his PhD-study, Georg, in his role as the Vice-President of SIL-Austria and National Representative of the SIL International (Societas Internationalis Limnologiae), tries to connect young limnologists and their research in and around the European Alps.

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Georg Niedrist MSc.
University of Innsbruck
Institute of Ecology
River and Conservation Research

Phone: +43 (0)512 507 51742
email: g.niedrist@student.uibk.ac.at
web: http://www.uibk.ac.at/ecology/staff/persons/niedrist.html.en

 
Daniela Sint

What’s on the menu?

Daniela Sint is a senior member of the working group Applied and Trophic Ecology headed by Michael Traugott, which is among the world leading groups investigating trophic interactions with molecular methods (www.uibk.ac.at/ecology/forschung/biodiversitaet.html.en).

Eating and been eaten is a basic concept of life and, no wonder, feeding interactions are a major topic in ecology. While it’s rather easy to watch a grazing cow or identify the prey of lions, most trophic interactions are much harder to observe. Be it due to the minute size of the organisms (e.g. springtails), their hidden life style (e.g. in the soil) or the inaccessibility of their habitat (e.g. the deep sea).

Fortunately, recent advances in molecular methods allow us nowadays to identify species and investigate their trophic interactions based on the presence/absence of DNA. This means we can identify on which roots a soil-living animal has nibbled, simply by tracking the plant DNA in its gut or faeces. Such information is essential to understand the mechanisms influencing the structure and function of species communities in different ecosystems – a main focus in many (inter-)national research projects conducted by the working group.

In projects funded by the FWF and the BMWFW Daniela and her colleagues are currently investigating the influence of fertilizers in cereal fields on the invertebrate community, food web interactions and associated ecosystem services such as pest control.

Dr. Daniela Sint

 

Albin Hammerle     

Sink or not a sink, that’s the question!

Albin Hammerle is part of the biometeorology working group headed by Georg Wohlfahrt (www.biomet.co.at). Basically his work might be condensed to the question which conditions cause an ecosystem to be a sink or a source for greenhouse-gases?

The still very high uncertainty on the terrestrial ecosystem GHG-budgets, the likely changes in future climate and the responses of terrestrial ecosystems related to it including possible feedbacks are the motivation for his profession.

 
To answer these questions Albin is involved in several national and international projects dealing with the exchange of climate-relevant gases like CO2, CH4, CO, N2O, COS and energy (water vapor and sensible heat), mainly working with methods based on micrometeorological theory combined with a strong background in ecosystem modelling.

In his current project, funded by the FWF, on the land-atmosphere carbon monoxide exchange he tries to reduce the uncertainty of the terrestrial contribution to the CO budget. Furthermore he investigates the above- and below-ground flux contributions to the ecosystem-scale CO exchange by simultaneous measurements of CO exchange through the soil surface in situ along with the ecosystem-scale CO fluxes.

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Dr. Albin Hammerle
University of Innsbruck
Institute of Ecology
Ecosystem and Landscape Ecology

phone: +43 (0)512 507 51612
email: albin.hammerle@uibk.ac.at
web: http://www.uibk.ac.at/ecology/