Dr. Susanne Fritz
Emmy Noether Research Group Leader
Junior research group: Macroevolution of climatic niches in birds (DFG Emmy Noether project FR 3246/2-1)
7-3.10: BIODIVERSITY AND AREA DYNAMICS OF VERTEBRATES
7-3.12: ECOMORPHOLOGY OF FRUGIVOROUS BIRDS ALONG AN ELEVATIONAL GRADIENT IN THE TROPICAL ANDES
Fields of interest
I am interested in the processes underlying large-scale biogeographic and phylogenetic patterns and their relationships with the abiotic environment, and in consequences for global conservation prioritisation. I have worked on ecology, evolution and conservation of mammals, amphibians and birds, and am now focusing on macroevolution and biogeography of birds and mammals.
Subject Editor at Ecography
Associate Editor at Frontiers of Biogeography
29/04/2014 - Gehen oder bleiben? – Neue Emmy Noether-Gruppe erforscht die Klima-Anpassung von Vögeln (in German only)
Teaching at Goethe University Frankfurt:
Macroevolution of climatic niches in birds
In 2014, I started as a Emmy Noether research group leader financed by the DFG (German Research Foundation). The project includes two PhD students, Alison Eyres and Anna Phillips. Key collaborators are Prof. Dr. Katrin Böhning-Gaese, Dr. Jussi Eronen, Dr. Johan Liakka, Prof. Dr. Andreas Mulch, and Dr. Till Töpfer(Zoologisches Forschungsmuseum Alexander Koenig in Bonn).
We want to investigate the evolutionary and ecological processes that shape species` climatic niches, i.e. the climatic conditions that living species can be found in. The project will use a macroevolutionary comparative framework across selected key taxa of passerine birds with migratory and sedentary species, because migratory and sedentary species experience vastly different climatic conditions throughout the year. We want to know whether migratory species track their climatic niches when they move from breeding to wintering areas and vice versa, and whether climatic niches of sedentary birds are then larger throughout the year than for migratory birds (because sedentary birds have to take seasonal climatic variation as it comes). Is climatic niche evolution across migratory and sedentary birds linked to paleo-climatic conditions? And how is climatic niche evolution related to trait evolution, especially for traits that quantify other ecological niche parameters, such as diet or habitat? Finally, can we find a relationship between the speed of climatic niche evolution and the diversification of clades, i.e. the speciation and extinction of avian lineages?
Macroevolution, macroecology and biogeography – the big picture
This part of my work focuses on bringing together large-scale biogeographical patterns and macroevolutionary processes. Using global databases and molecular phylogenies, I am trying to separate influences of evolutionary history, species’ traits, and current environmental variation on species richness and community composition. Why are some regions so much more species-rich than others? Why do these hotspots of biodiversity coincide for many groups, but not for others? And what are the underlying evolutionary patterns and ecological processes generating and maintaining the astonishing diversity of Life on Earth?
My most recent work brings together paleontological data on past environmental conditions and extinct species with contemporary data on the current environment and living species. Research in ecology and evolution in general is usually split between paleontological and neontological studies. With colleagues and guest researchers at BiK-F, I have recently published a conceptual framework for the integration of paleontological and neontological perspectives (Fritz et al. 2013). We highlight the opportunities arising from integrating paleontological and neontological research when addressing key questions in (paleo-)ecology and evolution: which mechanisms generate spatial and temporal variation in diversity, how do traits evolve, and which processes determine the temporal dynamics of geographical ranges and ecological niches. By capitalizing on data and methods from both disciplines, this integration will advance understanding of the fundamental processes that generate and maintain diversity in time and space.
With colleagues from the Center for Macroecology, Evolution and Climate at the University of Copenhagen, we have recently updated the map of global biogeographic regions originally introduced by A. R. Wallace in the 19th century. The study used distribution maps and phylogenetic trees of over 20,000 species of terrestrial vertebrates, and came up with a few new regions while confirming much of the old knowledge on faunal boundaries (Holt, Lessard et al. 2013). It has also generated some interesting scientific controversy (comment by Kreft & Jetz 2013 and our response).
Several projects with Dr. Knud Jønsson, now at Imperial College London, investigate diversification rates of passerine bird families as estimated from molecular phylogenies. In particular, we are interested in whether and how diversification rates have varied over time, and whether this variation can be related to the different biogeographic histories or species traits of the groups. A first paper compared four South-East Asian radiations, including the wonderful birds-of paradise on New Guinea (Fritz, Jønsson et al. 2012 and press release above). One of the most striking examples of adaptive radiation, i.e. the diversification of a group of species into different ecological niches, are the vangas of Madagascar. The vangas are spectacular because of their incredible diversity in feeding ecology and beak morphology, which seems to be linked to their diversification rates (Jønsson et al. 2012).
Beyond these highlighted publications, I have published on global phylogenetic and biogeographic patterns in mammals and amphibians, elevational diversity patterns and seed-dispersal networks in birds, the current state and future challenges for macroecology as a field, and global climatic niche conservatism in mammals and amphibians (see above for my full publication list).
Highlighted publications on macroevolution, macroecology and biogeography
S. A. Fritz*, K. A. Jønsson*, J. Fjeldså, C. Rahbek (2012) Diversification and biogeographic patterns in island radiations of passerine birds. Evolution 66: 179-190. Links: Abstract, press release (in German)
S. A. Fritz*, J. Schnitzler*, J. T. Eronen*, C. Hof*, K. Böhning-Gaese*, C. H. Graham* (2013) Diversity in time and space: wanted dead and alive. Trends in Ecology and Evolution 28: 509-516. Links: Abstract, press release
B. G. Holt*, J.-P. Lessard*, M. K. Borregaard, S. A. Fritz, M. B. Araújo, D. Dimitrov, P.-H. Fabre, C. H. Graham, G. R. Graves, K. A. Jønsson, D. Nogués-Bravo, Z. Wang, R. J. Whittaker, J. Fjeldså, C. Rahbek (2013) An update of Wallace’s zoogeographic regions of the world. Science 339: 74-78. Links: Abstract, press release
K. A. Jønsson, P.-H. Fabre, S. A. Fritz, R. S. Etienne, R. E. Ricklefs, T. B. Jørgensen, J. Fjeldså, C. Rahbek, P. G. P. Ericson, F. Woog, E. Pasquet, M. Irestedt (2012) Ecological and evolutionary determinants for the adaptive radiation of the Madagascan vangas. Proceedings of the National Academy of Sciences of the United States of America 109: 6620-6625. Links: Abstract, press release
* equal author contributions
Past, current and future human impacts on biodiversity
My PhD thesis, supervised by Prof. Andy Purvis at Imperial College London, investigated the processes behind current global patterns of species’ extinction risk, a topic that I am still interested in. Many species today are threatened with extinction, and the pattern of extinction risk is complex both phylogenetically and geographically. Why are some species and clades more threatened than others? Is it just where they live, so due to spatial variation in anthropogenic threats, or is there something about their biology that makes them more susceptible? Which species traits are commonly associated with high extinction risk from habitat loss, climate change, or overexploitation? Finally, do these trait-extinction risk associations hold across different regions and clades and can we see the same associations in fossil species that have already gone extinct?
Recently, I have been part of a working group in Australia (sponsored by the Australian Centre for Ecological Analysis and Synthesis, ACEAS), which looked into the reasons behind on-going declines of tropical marsupials (Fisher et al. 2013). Australia has experienced a third of the known historical mammalian extinctions, but most of these were concentrated in medium-sized species of the arid areas, and many have been blamed on introduced red fox. However, since the 1970s dramatic population declines are occurring in marsupials of the fox-free northern tropics. We found that declining northern species were small and associated with savannah habitats, whereas in the south medium-sized species in open dry habitats were declining. Our results indicate that fox are continuing to threaten mammalian diversity in the southern half of Australia, but in the north, feral cats may pose increasing problems for survival of small mammals.
During my PhD, I investigated the association of biological species traits with current global extinction risk for over 5000 mammal species (Fritz et al. 2009). My results indicated high spatial heterogeneity in traits that increase risk: for example, big mammals were at higher risk only across South America, Africa and South-East Asia. Interactions with different anthropogenic threats indicate that these regions have been converted to agricultural land use much more recently than others, so there may be an extinction filter operating that has already affected big mammals in Europe, North America and Australia and is now striking across the tropics. In collaboration with Dr. Sam Turvey from the IOZ London, we included over 200 species that have gone extinct during the Holocene in similar analyses and came to the same conclusions (Turvey & Fritz 2011).
In another study, I estimated possible future impacts of current patterns of extinction risk in mammals, which highlighted that future losses of functional diversity may be much more severe than losses of species richness and phylogenetic diversity (Fritz & Purvis 2010). The selectivity of current extinction risk means that we stand to lose a very biased sample of global diversity, with potentially severe consequences for ecosystem functioning in some areas of the Earth.
Highlighted publications on anthropogenic impacts
D. O. Fisher, C. N. Johnson, M. J. Lawes, S. A. Fritz, H. McCallum, S. P. Blomberg, J. VanDerWal, B. Abbott, A. Frank, S. Legge, M. Letnic, C. R. Thomas, A. Fisher, I. J. Gordon, A. Kutt (2014) Contemporary marsupial decline and extinction in tropical Australia: is history repeating? Global Ecology and Biogeography 23: 181-190.
S. A. Fritz, O. R. P. Bininda-Emonds, A. Purvis (2009) Geographical variation in predictors of mammalian extinction risk: big is bad, but only in the tropics. Ecology Letters 12: 538-549. Link: Abstract
S. A. Fritz, A. Purvis (2010) Phylogenetic diversity does not capture body size variation at risk in the world’s mammals. Proceedings of the Royal Society B: Biological Sciences 277: 2435-2441. Link: Abstract
S. T. Turvey, S. A. Fritz (2011) The ghosts of mammals past: biological and geographical patterns of global mammalian extinction across the Holocene. Philosophical Transactions of the Royal Society B: Biological Sciences 366: 2564-2576. Link: Abstract