Integrated modelling of the response of aquatic ecosystems to land use and climate change in the Poyang lake region, China
Final Report Abstract
We developed an integrated modeling approach to assess the impact of fast environmental changes on aquatic ecosystems. Three different models were integrated through a dynamic DPSI-system (Driver, Pressure, State and Impact) which serves as a framework to link the models SWAT (catchment processes), HEC-RAS (in-stream processes) and BIOMOD (species distribution model; SDM). The major drivers served as model input data (e.g. climate, land use), while the pressures on the ecosystem (hydrological stress, sediment inputs) were defined and represented in the model algorithms of SWAT and HEC-RAS. Based on the multiple pressures, the state of the freshwater habitats (e.g. flow, water depth, substrate) were produced as outputs of these models. Finally, the impact on the aquatic ecosystems is evaluated by analyzing the distribution ranges of stream macroinvertebrates modeled by BIOMOD. The result of this model linkage enhances the understanding of (1) how landscape processes and sediment transport interact with ecohydrological and aquatic system properties and (2) how the impact of land use, climate and hydromorphological change on aquatic ecosystem properties can be assessed. Data was collected in the selected study site: the upper Changjiang catchment, a tributary to the Rao River, which drains into Chinas largest freshwater body, the Poyang Lake. Four trips to China were arranged: the first one to gather preliminary information to plan the sampling campaign; the two following ones to carry out sampling in the field and carry out sample analysis; and a last trip to finish sample analysis and for specimen identification as well as to discuss results. Despite climatic and bureaucratic setbacks, two full sampling campaigns were accomplished with success. The setup of the individual models, as well as the data transfer was successfully achieved: daily runoff and sediment data from the SWAT model served as input to a HEC-RAS model; daily runoff data from the SWAT model was used as an environmental predictor in an SDM; several hydraulic variables from the HEC-RAS model were used as environmental predictors in a SDM. The use of these hydrological and hydraulic predictors for entire stream networks, a novel approach in distribution modeling, yielded good results in the four models that were built for two different catchments it was tested in. For the final integrated model in the Changjiang catchment the ecohydrological SWAT model has been set-up, calibrated and validated. Land use scenarios representing different fractions of land use have been created to simulate potential environmental changes. Future climate data for the period 2021-2050 has been adapted to the study catchment. With these environmental predictors, changes in the distributions of stream macroinvertebrates are projected and the effects of either climate change, land use change or both, can be evaluated.
Publications
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(2010): Considering aquatic habitat properties in integrated river basin management - an ecohydrological modelling approach. In: Hydrocomplexity: New tools for solving wicked water problems. Kovacs Colloquium. UNESCO, Paris July 2010. Ed.: S. Khan et al. IAHS Redbooks 338. 137-139
Kiesel, J., Fohrer, N. & Schmalz, B.
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(2010): Ecohydrological research in the Poyang lake region in China. European Geosciences Union (EGU) General Assembly 2010, 02.- 07.05.2010, Vienna, Austria. Geophysical Research Abstracts, Vol. 12, EGU2010-12727
Schmalz, B., Fohrer, N., Jähnig, S.C., Cai, Q. & Bieger, K.
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(2011): Reaktion von aquatischen Ökosystemen auf Landnutzungs- und Klimaänderungen im chinesischen Poyang-Gebiet - DPSI-Konzept einer integrierten Modellierung. In: Blöschl, G. & Merz, R. (Hrsg.): Hydrologie und Wasserwirtschaft – von der Theorie zur Praxis. Forum für Hydrologie und Wasserbewirtschaftung der FgHW, Heft 30.11. P. 348. ISBN: 978-3-941897-79-3
Schmalz, B., Fohrer, N., Jähnig, S. & Cai, Q.
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(2012): Accuracy, reproducibility and sensitivity of acoustic Doppler technology for velocity and discharge measurements in mediumsized rivers. Hydrological Sciences Journal 57(8): 1626–1641
Song, S., Schmalz, B., Hörmann, G. & Fohrer, N.
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(2012): Hydrologische und hydraulische Ergebnisse eines integrierten Modellierungsansatzes in einem mesoskaligen chinesischen Einzugsgebiet. In: Weiler, M. (Hrsg.): Wasser ohne Grenzen. Forum für Hydrologie und Wasserbewirtschaftung der FgHW, Heft 31.12. P. 375. ISBN 978-3- 942964-38-8
Schmalz, B., Strehmel, A., Song, S., Kuemmerlen, M., Cai, Q., Jähnig, S.C. & Fohrer, N.
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(2012): Integration of hydrologic variables in species distribution models of freshwater benthic macroinvertebrates: two case studies. Proceedings of the annual meeting of the German Limnological Society 2011 in Weihenstephan, Germany
Kuemmerlen, M., Schmalz, B., Domisch, S., Kiesel, J., Fohrer, N., Cai, Q., Jähnig, S.C.
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(2012): Integrierte Modellierung von aquatischen Ökosystemen in China: Arealbestimmung von Makrozoobenthos auf Einzugsgebietsebene. Hydrologie und Wasserwirtschaft HW 56(4): 185- 192
Kuemmerlen, M., Domisch, S., Schmalz, B., Cai, Q., Fohrer, N., Jähnig, S.C.
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(2012): Integrierte Modellierung von aquatischen Ökosystemen in China: Ökohydrologie und Hydraulik. Hydrologie und Wasserwirtschaft HW 56(4): 169-184
Schmalz, B., Kuemmerlen, M., Strehmel, A., Song, S., Cai, Q., Jähnig, S.C. & Fohrer, N.
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(2012): Modelling of riverine ecosystems by integrating models: conceptual approach, a case study and research agenda. J. Biogeogr. 39: 2253–2263
Jähnig, S.C., Kuemmerlen, M., Kiesel, J., Domisch, S., Cai, Q., Schmalz, B. & Fohrer, N.
