As others in this blog have reported, ecohydrology is strictly associated to the broad concept of “interaction” between water-related processes and the biotic component of the ecosystems. I’m currently teaching a graduate course in “Hydrology of the Wildlife Systems”, basically a combination of stream ecology and ecohydrology: I have not done any statistics but I can easily realize that the words I tell most often to the students are “water”, “ecosystems” and “interaction”, and I’m trying to stimulate them to achieve a wide thinking and a far-reaching view on how the different components in the environment are closely linked and influencing each other. To me, ecohydrology means studying the functional interrelations between water and vegetation in the critical zone, with a particular focus on forested catchments and agricultural areas. I’m particularly interested in how plants (trees but not only) affect the hydrological cycle and the hydrological processes at the catchment scale, and vice-versa, and how human inputs in anthropic settings (e.g, irrigation) influence tree response and sources of water uptake which in turn play a role on water stored in soil and in shallow groundwater.
What are your undergraduate and graduate degrees in?
I have a B.S. and M.S. in Natural Sciences from the University of Milan (Italy), with a thesis based on a phytosociological (and partially geomorphological) analysis of spruce population dynamics in an Alpine valley. So, trees were my first love. I then moved to the University of Padua (Italy) where I obtained a one-year degree on Hydrological and Geological Hazard Assessment and Mitigation followed by another M.S. in Forest and Environmental Sciences.
I have a PhD in Management of Water Resources from the same university: I pushed vegetation dynamics aside for a while and started to work on spatial and temporal patterns of soil moisture in a beautiful mountain catchment in the Italian Dolomites, under the supervision of prof. Marco Borga.
How did you arrive at working in/thinking about ecohydrology?
During my PhD I was trained as an experimental catchment hydrologist, and I began using environmental tracers to study catchment- and hillslope-scale runoff generation processes. I did not forget my background on trees but I tended to see precipitation, meltwater, stream water and subsurface water as the only fundamental elements of any catchment, while (evapo)transpiration was somehow a “resulting” process. Then, the rapid development of laser spectroscopy for the determination of stable isotope ratios in water, easier to operate and more affordable compared to traditional mass spectrometry, combined with a growing interest of the scientific community towards isotope-based analysis of tree water uptake pushed me to start investigating the spatial and temporal variability of water sources accessed by trees in forest and agricultural settings. These efforts are leading me to learn more, expand my knowledge and obtain a broader, more comprehensive and exciting perspective on the ecohydrological relations between vegetation and the other components of the water cycle in the critical zone.
What do you see as an important emerging area of ecohydrology?
Although it should be implicit in the concept of ecohydrology, I think that increasing the interdisciplinary approach is a critical step to further advance ecohydrological studies. I have the feeling that quite often, at least in my experience, researchers try to expand their own research lines, interests and knowledge to include multiple analysis perspectives but a real combination of people with different expertise and backgrounds is not fully achieved. I realize this, for instance, when I try to think as a plant physiologist or a geomorphologist or an ecologist to frame some questions. But I’m not, and this affects the way I analyse data and interpret results. I believe a stronger collaboration among different but related disciplines is necessary in order to address scientific aspects of ecohydrology (including the role of anthropic pressure) with a wider angle of view and thus in a less-skewed, more solid way.
I agree with Holly (see her post below) about the scaling issue. Most studies are typically carried out at the plant or stand scale but we still need to figure out how to build models to upscale the spatio-temporal variability in plant water uptake from the plant/stand scale to the catchment/landscape scale. This is an open challenge that has relevant practical implications, for instance for water resource management in forestry and agriculture.
I like the potential (but I’m also aware of the limitations) of meta-analyses (Evaristo and McDonnell, 2017). As far as I, know this approach is quite common in medical science, especially with the aim to increase data availability and reach higher statistical power. I think this tool can have fruitful applicability in ecohydrology in order to achieve a better understanding of processes in a wide variety of environments. At the same time, I advocate the more frequent use of multi-comparison investigations (in ecohydrology as well as in catchment hydrology). Although comparative studies can be time- and money-consuming, through the analysis of differences they can go beyond understanding the behavior of individuals or single study sites and allow for a better perception of the factors that control those differences. And the factors that drive changes in the ecosystems and of their services are what we should be more interested in.
Do you have a favorite ecohydrology paper? Describe/explain.
It’s hard to pick just one. Considering papers that focus on the intertwined processes between water and trees, I especially like the review by Susan Brantley and co-authors (Brantley et al., 2017) who tested several hypotheses to highlight how trees, seen as biotic engines, promote soil-landscape co-evolution by acting as “builders and plumbers” of the critical zone. One of the first papers I read when I dove in on the use of isotopes to investigate sources for tree water uptake and related ecohydrological dynamics is the work by Greg Goldsmith and colleagues on ecohydrological processes in a mountain cloud forest in the tropics (Goldsmith et al., 2012). This paper, along with the already-cited and inspiring one by Dawson and Ehleringer, 1991 (I agree with Holly again!) opened my eyes on the exciting opportunities isotopes offer to explore interrelations between vegetation and hydrological processes, including still unsolved (and therefore fascinating) issues. Finally, I recommend a recent paper by Barbeta and Peñuelas, 2017: their isotope-based work underlines the importance of groundwater contribution to plant transpiration across different biomes and provides new insight about the occurrence and interpretation of the highly-discussed “two water worlds hypothesis” (McDonnell, 2014).
What do you do for fun (apart from ecohydrology)?
Apart from ecohydrology I do catchment hydrology, of course! Joking aside, I’m a commuter and I’m away very often. So, when at home, I try to spend as much time as possible with my wife and our two children and with our friends, preferably in the outdoors. I love cycling, hiking in the mountains, skiing, playing guitar, reading, and I’m fond of nature photography.