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Research Philosophy


Demand-driven research for evidence-based policies:

Mankind has introduced new selective powers to the world, and some of our ways how we manage this planet could be interpreted as a master plan to drive species into extinction. For me as a riverscape/wetland ecologist, this tragedy becomes specifically evident when regarding the dramatic fate of migrating fish and riparian biota. It is a special task for us to improve management and engineering approaches that sustain biodiversity and maintain ecological functions even in intensively used ecosystems. We need a better understanding of the functioning of the systems and a “river culture” to integrate these insights into management strategies.
The Rhine near Karlsruhe. The floodplain (right) lies several meters deeper than the river channel (left). Sophisticated engineering is necessary to re-establish contact between these originally interacting parts of the same ecosystem.

 

Sustainable management and ecological engineering:

Starting from basic ecological research, my work has always been targeted to deliver elements for safegarding natural and cultural diversity. Streams in the Brazilian Cerrado are phantastic research objects, but they are practically all threatened by erosion in their catchments. Thus I gathered scientists and practitioners to develop and implement techniques to assess these impacts and to protect the catchments. Similarly, studies on the ecology of the Pantanal resulted in the development of a sustainable management concept for this marvelous wetland in the heart of Latin America including traditional use forms by the local human population. In the CarBioCial Project (www.carbiocial.de), we make practical use of the decomposition studies by developping new approaches to combat climate change in large tropical agroscapes.
In the CARBIOCIAL project, we analyze new techniques to increase carbon storage in farm soils and to valorize riparian zones of streams as natural carbon stocks (Wantzen et al. 2011).

 

Functional ecology of freshwater ecosystems and their aquatic-terrestrial transition zones:

One foci of my research lies in the organism-mediated transfer of carbon in these systems, e.g. how do streams profit by terrestrial organic matter input from the neighboring forest? How do floodplain organisms use the ressources during and after the change from wet to dry conditions? The comparison between tropical and temperate systems using stable isotope analysis (SIA) helps us understand these processes better and to develop further ecological concepts such as the updates of the Flood Pulse Concept in rivers, streams and lakes (Junk & Wantzen 2004, Wantzen et al. 2006).
Piraputanga (Brycon hilarii) feed in the flooded areas of the Pantanal where they may take up about one third of their carbon from terrestrial organisms (Wantzen et al. 2002).

 

Organic matter processing:

Nature teaches us how recycling can be made most efficiently. Which characteristics of this organic matter influence the decomposition process? In the “WW-DECOEX-Project” I gathered colleagues from all over the world to develop and improve conceptual models for organic matter processing. Chemical analysis (HPLC) and new bioassays provided new insights on effects of plant secondary compounds. The results are applied in sustainable use concepts.
Invertebrate shredders decompose tree leaves in streams – why do they occur very rarely in some streams and are common in others? (See Wantzen & Wagner 2006 for answers)

 

Invasive species:

River Channelization and global transport facilities break down existing biogeographical barreers and speed up the distribution of species. In Lake Constance, we could study the effects of a recent invasive crustacean (Dikerogammarus villosus) and identify some weak points of this species, which may be subject to ecosystem management. Future management strategies need to consider how negative effects of invaders can be reduced or even transformed into positive effects for ecosystems. Currently, in the SIAL project, we are studying the effects of invading Corbicula clams on the Loire River.
Corbicula clams have recently invaded the Loire: which effects do they have?

 

Biodiversity and Conservation:

Freshwater species numbers are decreasing overproportionally fast. We need to be able to identify species, make inventories, study the ecological requirements of species and develop policies to maintain biodiversity and its evolutive power. For the first aspect, I contribute to the ABLA (Aquatic Biodiversity in Latin America, http://www.pensoft.net/series.php?ser=729) book project, providing revisions, keys and ecological data of important taxonomic groups. For the second, my colleague Sabine Greulich and I have started the Biodiversity platform for the Loire river (OBLA-project), in which we want to gather all available biogeographical and taxonomical information on the Loire, and with our colleagues we develop a protocol for regular sampling and experimentation. For the third point, I am developping a project to preserve the last populations of the Giant Freshwater Pearlmussel (Margaritifera auricularia) in French and Spanish water courses. Our aim is to reintroduce this species in recovering river systems. The “Landscape and Environment” workgroup of our CNRS cluster CITERES deals with environmental policies on the French and European scale, currently involving 3 PhD studies.
A huge specimen of Margaritifera auricularia. This species needs sturgeon and other migratory fish for its dispersal . It used to be commen all over Europe – today it is nearly extinct.

River Culture:

Floods are today considered as a threat and a risk, rather than considering them as what they are: a natural element of hydrological patterns of rivers. The occurrence of floods and low-discharge periods to a given time are perfectly normal hydrological features. The biota and many human cultures are not only adapted to these changes, they even need them for survival. Floods mobilise ressources from the terrestrial phase for the aquatic organisms and vice versa, see the Flood Pulse Concept (FPC). Floods and droughts are equally important to reshape habitats due to sediment dynamics. It is one of the major tasks for river management to redynamize our rivers in order to facilitate their ecosystem services and to reinforce biodiversity. Here, we can learn a lot from the “River Culture” of traditional societies that have learned to live in the rhythm of the water.
“If you build your house in the vicinity of a river, don’t be surprised if your neighbor shows up from time to time.” Stilt houses are known since the neolithic age, they give an example how it is possible to live in harmony with the pulsing nature of rivers and lakes.