Landscape Ecohydrology

We aim to understand how catchments function ecohydrologically at different spatio-temporal scales, i.e how and how long is water stored and released in landscapes. For this, we link landscapes and riverscapes by understanding the physical processes that generate stream flow, and the way these processes influence the hydrochemistry and ecohydrology of streams. One of our main tools is the use of stable isotope tracers as "fingerprints" of waters to quantify internal processes of water storage, transmission and release, and ecohydrological fluxes across spatio-temporal scales. We integrate our extensive environmental data into ecohydrological models (the group developed the tracer-aided model EcH2O-iso) to parameterise ecohydrological interactions in a physically-based way. This allows the effects of vegetation on water usage and the direct effects of climate and landuse change on water flow paths and availability to be quantitatively assessed.

These models use coupled isotope-hydrology water tracking to simulate stable isotope ratios and their transformation from precipitation to stream flow through fluxes in vegetation canopies, rooting zones, deeper soils and groundwater aquifers. These approaches also allow us to estimate ages of water. One goal is to investigate soil-vegetation-atmosphere-water dynamics through tracers and tracer-aided modelling to quantify the heterogeneity in spatio-temporal patterns of "green" (evaporation and transpiration) and "blue" (groundwater recharge and runoff) water fluxes and to identify how plant water use will affect and possibly alter signals of potential climate change.

We work at three main experimental sites: (i) The Demnitzer MillCreek catchment in the East of Brandenburg, Germany, which has soil and vegetation conditions representative of the drought-sensitive parts of NE Germany and central Europe; (ii) The Girnock Burn catchment in NE Scotland, which is characteristic for cool northern climates with deep organic soils; (iii) the urban area of Berlin, where we also conduct extensive monitoring of atmosphere-soil-vegetation-stream flow interactions is also conducted in the city of Berlin to understand these processes in urban settings and thus, support decision-making for sustainable urban development. Finally, we use local processed-based insights from different geographical environments from international inter-catchment comparisons to synthesise a more holistic understanding of hydrological and ecological function.

In summary, our research delivers new scientific understanding for assessing how different land use affects "green" and "blue" water partitioning, providing a crucial basis for evaluating how water storage and flux dynamics can be mediated by land management strategies to build resilience and to protect water resources against future climate change.

Within Department 1, Ecohydrology & Biogeochemistry, our team addresses the three departmental core areas of research: Landscape-waterscape interactions; ecohydrology and biogeochemistry of urban and disturbed systems; and abiotic-biotic coupling.

Here some examples of our current projects:

Evaluating the storage-flux-isotope-water age spatio-termporal interactions and partitioning of “blue” (groundwater and surface water) and “green” (evapotranspiration) water in the Demnitzer Mill Creek catchment using the physically based- tracer-aided ecohydrological model, EcH2O-iso (Dr. Aaron Smith) e.g. Smith AA, et al (2021) Quantifying the effects of land use and model scale on water partitioning and water ages using tracer-aided ecohydrological models. Hydrology and Earth System Science. (HESS); Kleine L,  et al (2021) Modelling ecohydrological feedbacks in forest and grassland plots under a prolonged drought anomaly in central Europe 2018-2020. Hydrological Processes.

Using temporal high-resolution in-situ measurements of moisture, energy balance, and tracers with the tracer-aided ecohydrological  model, EcH2O-iso, we explore the complex mixing and transit times and interactions of vegetation and soil water. (Dr. Aaron Smith)

Using measurements of soil moisture as well as stable isotopes in both soil and xylem water with the tracer-aided ecohydrologcial model EcH2O-iso, we explore the differences in water partitioning between urban trees and grassland. This research can for example help inform policy makers optimize the use of urban green spaces combating urban heat or to promote groundwater recharge. (Dr Mikael Gillefalk) e.g. Gillefalk M, et al. (2021) Quantifying the effects of urban green space on water partitioning and ages using an isotope-based ecohydrological model. Hydrology and Earth System Sciences (HESS).

Monitoring hydrological, chemical, and isotopic signals and UAV-based multispectral reflectance to explore the role of land use types, vegetation dynamics, and climatic variability on water and nutrient cycling in the Demnitzer Mill Creek catchment (PhD Songjun Wu).

Using stable water isotopes and ecohydrological monitoring to investigate the interlinkages between the soil-plant-atmosphere continuum as well as the effects of specific land use types (forest, agriculture, and grassland) on the ecohydrological fluxes of the Demnitzer Mill Creek catchment (PhD Jessica Landgraf)

Using in-situ measurements and synoptic sampling to investigate high-resolution ecohydrological process dynamics at the urban soil-plant-atmosphere interface and the “green” and “blue” water flux partitioning (PhD Ann-Marie Ring)

With the aid of stable water isotopes and hydrochemistry as natural "fingerprints" of water we aim to understand how water is transported through the urban environment in terms of water sources, pathways and ages to disentangle the effects of urbanization on the water balance (PhD Lena-Marie Kuhlemann, Christian Marx)