Natasha Krell is a Ph.D. student working with the Kelly Caylor "Water, Vegetation and Society" (WAVES) Team at U.C. Santa Barbara.  She is also a current Fulbright Fellow to Kenya. 

Dr. Steve Loheide is a Professor in the Department of Civil and Environmental Engineering at the University of Wisconsin - Madison where he is the Director of the Hydroecology Lab.

What does ecohydrology mean to you?

Ecohydrology is the two-way interactions between hydrological processes and ecologic systems.  I prefer to interpret this very broadly to fit as many people and ideas under the ecohydrology circus tent as possible!
 
What are your undergraduate and graduate degrees in?

BS Geology; BS Environmental Chemistry; Minor Physics
MS Geological Sciences
PhD Hydrogeology
 
How did you arrive at working in/thinking about ecohydrology?

I always knew I wanted to be a scientist and study environmental issues, but it was a meandering path to land in the field of ecohydrology.  I started my undergraduate studies as a chemistry major, but couldn’t get into a single chemistry class during my first semester and got stuck in classes in physics and geology.  Turns out I liked both better than chemistry, so I picked them up as a minor and second major, respectively.  In looking for graduate programs, I wanted to combine my background in chemistry and geology, and isotope hydrogeochemistry seemed like a good mixture.  However, it wasn’t until my first year of my PhD that I realized I wanted to apply the technical hydrology skills I’d been developing to ecosystem restoration, which was the point at which I settled into ecohydrology.

What do you see as an important emerging area of ecohydrology?

I think the application of ecohydrologic knowledge gained mostly in natural ecosystems to agroecosystems, urban areas, and ecological restoration will only grow over the next 20 years.  Much – but not all - of the existing theory may translate well to human-dominated systems, but we will need to develop diverse observational data sets to test our understanding and improve our ability to guide these ecosystems along desirable paths in a world with ever changing drivers.

Do you have a favorite ecohydrology paper?  Describe/explain.

My personal favorite is the 1932 USGS report by Walter White, which makes use of watertable fluctuations to estimate groundwater use.  He makes an observation of a natural phenomenon, carefully determines its cause, and then finds a way to exploit it to understand and quantify system behavior.  This and other very old contributions have a thoroughness that not only conveys the result, but tells the story of the research.  My guess is that today’s editors (myself included) would consider 75% of the material extraneous, but those details and detours better convey the reality of the scientific process involved with field-based research and can make for a good read every once in a while.
 
White, W. N. (1932), A method of estimating ground-water supplies based on discharge by plants and evaporation from soil: Results of investigations in Escalante Valley, Utah, U.S. Geol. Surv. Water Supply Pap., 659-A.
 
 
What do you do for fun (apart from ecohydrology)?

My two children are in 5th and 6th grades and my wife and I like to spend time cheering them on at swim meets, soccer games, and hockey tournaments!  I myself enjoy running and boxing and love hiking whenever I can manage to find a mountain.

​Dr. Cynthia Gerlein-Safdi is a Junior Fellow from the Michigan Society of Fellows, hosted in the department of Climate and Space Sciences and Engineering at the University of Michigan (Ann Arbor, MI, USA). Twitter: @CGerleinSafdi, website: https://cgerleinsafdi.engin.umich.edu/

What does ecohydrology mean to you?
To me, ecohydrology means looking at a landscape, with soil, trees, and the sky above them, and understanding how water moves between these three elements. I’m especially interested in plants and how they transport water between the soil and the atmosphere, how they deal with drought, and how their water status affects their rate of CO2 uptake.

What are your undergraduate and graduate degrees in?
I did my BSc in geosciences and my MSc in geophysical engineering, both at the Ecole et Observatoire des Sciences de la Terre (EOST), an engineering school in Strasbourg, France. I then did a PhD in Civil and Environmental Engineering at Princeton University (NJ, USA). I was part of the program in Environmental Engineering and Water Resources.

How did you arrive at working in/thinking about ecohydrology?
Very gradually! I went into geophysics because I wanted to “find groundwater in the desert”. Turns out it’s not really what geophysical engineers do… For my masters, I worked on mapping soil moisture in Kenya. My next project was on tree roots. My PhD was on leaf water, and finally for my postdoc, I’m looking at trees from satellites to understand plant water content. It has been very interesting to study each piece of the puzzle separately throughout my education, and now I feel like I’m finally ready to look at the whole picture at once.

What do you see as an important emerging area of ecohydrology?
I’m fascinated by the amazing contribution that remote sensing can bring to ecohydrology. New sensors are developed and launched every year and it’s hard to keep up with all the new data, so a lot of it is underutilized. For example, microwave remote sensing can tell you about the water content of canopies. Simultaneously, we get photosynthetic activity of vegetation from solar induced fluorescence measurements. I think that ecohydrologists are really going to benefit from bringing all these different types of measurements together to get a more complete picture of the water cycle in different ecosystems. I also really love how remote sensing means that you can choose to study any place, vegetation, or climate in the world. It’s a bit like travelling but without leaving your desk!

Do you have a favorite ecohydrology paper?  Describe/explain.
Tough one! I think one of my favorite papers is: Ehleringer, J. R., & Dawson, T. E. (1992). Water uptake by plants: perspectives from stable isotope composition. Plant, Cell & Environment, 15(9), 1073–1082.  It is such an elegant paper that looks at where water in plants is coming from and where it goes, depending on the season. It combines stable isotope analysis of rivers, stem, and leaves, and in just a few pages, gives the reader a very complete picture of how plants uptake water. This paper was one of the founding papers for my PhD work using stable isotopes of water to look at transpiration suppression from dew deposition.  
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What do you do for fun (apart from ecohydrology)?
I’m an avid rock climber and runner. My husband and I travel regularly for climbing and it’s a really fun way to explore a new area. I also play the viola in local orchestras and chamber music groups. Finally, I have a three-month-old daughter and my new favorite hobby is to make her laugh! 

Adrian Harpold is an Assistant Professor in the The Department of Natural Resources and Environmental Science (NRES) at the University of Nevada, Reno where he directs the Nevada Mountain Ecohydrology Lab.

What does ecohydrology mean to you?
I take a very broad definition of ecohydrology, which is the interaction of water and ecosystems.  My personal interests are in the movement of water within and through terrestrial ecosystems (mountain ecosystems to be even more specific).  While the foundations of ecohydrology developed by Peter Eagleson and others focused on arid vegetation water use remain important, I am excited by a more inclusive vision of ecohydrology for the 21st century that engages a wide swath of diverse people to tackle critical societal problems.

What are your undergraduate and graduate degrees in?
All of my degrees are in engineering departments that were previously agricultural engineering.  I did my undergraduate and masters degree at Virginia Tech University in the Biological Systems Engineering department.  I then completed my Ph.D. in the Biological and Environmental Engineering department at Cornell University in 2010.

How did you arrive at working in/thinking about ecohydrology?
I have always been interested in water since my earliest memories in the creeks in our backyard in western Washington.  During the first two summers of my undergraduate engineering degree I was a raft guide on the Snake River in Wyoming. I believe this experience focused my interests on hydrology.  During my masters degree I designed a large particle image velocimeter to measure stream discharge and started playing in streams.  For my Ph.D. work I was interested in catchment hydrology and streamflow generation processes, which led me to research projects in the Catskill mountains.  However, it was not until my first postdoctoral positions at the University of Arizona and University of Colorado that I recognized the potential to help develop the field of mountain ecohydrology, focused on montane forest ecosystems and there interactions with snow and catchment hydrology. The culmination of this scientific training and mentorship leaves me with the opinion that the ‘big’ research questions in mountain hydrology lie at the interface of hydrology and ecology.

What do you see as an important emerging area of ecohydrology?
Using novel observations to better simulate mountain vegetation in hydrological models will be critical to predicting future water availability.  For example, our hydrology models often make simplistic assumptions about rooting depth and architecture, but are highly sensitive to these parameters.  Similarly, knowing at what depths vegetation are extracting water is critical to accurate predictions of response to water stress.  Another example that is a focus of my research in the Sierra Nevada, is improving understanding of how forest vegetation will respond to earlier snow melt and water inputs.  Do trees utilize earlier snowmelt and rain water?  How do these trees fare later in the season during a drier growing season? How does this alter larger scale carbon budgets?  Key to resolving these questions and vegetation in hydrological models more broadly, is leveraging new and better observations.  While I don’t expect a ‘silver bullet’ observation technique in the near future, the ability to co-locate more and more observations like eddy covariance, sap flow, and micrometerology, geophysics, and isotope hydrology to measure ecosystem water use in multiple ways has the potential to revolutionize the field.

Do you have a favorite ecohydrology paper?  Describe/explain.
I cannot pick a single favorite paper in ecohydrology, but the paper by Elizabeth Garcia in 2016 (Garcia et al., 2016) has all the pieces of a classic ecohydrology paper and is highly relevant to the emerging research areas identified above.  Garcia et al. show that the carbon allocation scheme of the vegetation (e.g. whether they store carbon above or below ground) has implications for water use efficiency and ultimately streamflow.  They combine observations, models, and theory to show that current ecohydrological model predictions may be neglecting key processes driving their response to climate change. Garcia et al. (2016) made me reflect considerably on linkages between water and carbon cycles in Sagehen Creek, one of their study sites, and what new observations we could leverage to answer this problem.  This paper forced me to learn new things and broaden my understanding of key ecohydrological processes, which has ultimately led to new insight and better research in this topic.
Garcia, E. S., Tague, C. L., & Choate, J. S. (2016). Uncertainty in carbon allocation strategy and ecophysiological parameterization influences on carbon and streamflow estimates for two western US forested watersheds. Ecological modelling, 342, 19-33.
 
What do you do for fun (apart from ecohydrology)?
My most important work outside of office, field work, and classrooms takes place at home with my wife and almost 2-year old daughter.  We like to explore our local Sierra Nevada and Great Basin mountains, as well as do big summer camping trips in the West. When life permits, I try to sneak out for bike rides and telemark turns around Reno and Lake Tahoe.

Tony Parolari is an Assistant Professor in the Department of Civil, Construction, and Environmental Engineering at Marquette University.

What does ecohydrology mean to you?
By definition, ecohydrology refers to the study of interactions between ecosystems and the water cycle. However, I understand the term to more broadly represent the important role water and hydrology play in living systems, including human society – from water and food security to recreation and the sustainability of ecosystems we depend on.

What are your undergraduate and graduate degrees in?
Both my undergraduate and graduate degrees are in Civil and Environmental Engineering. My undergraduate curriculum was focused in traditional civil engineering disciplines and my primary interests were in environmental chemistry and microbiology. As a PhD student, my coursework and research transitioned more toward ecology, hydrology, and modeling.

How did you arrive at working in/thinking about ecohydrology?
I’ve always seen it as more or less a random sequence of fortunate events. In my first job out of college, I worked as a hydraulic and hydrologic modeler at an engineering consulting firm in Boston. This was my first experience in hydrology outside of the classroom and I really enjoyed it. While in Boston, I got involved with the local Engineers Without Borders chapter and had the opportunity to meet a few graduate students studying hydrology and ecohydrology in the Parsons Lab at MIT. I was considering a PhD at the time and they had great things to say about the program. Lo and behold, I was accepted, joined Rafael Bras’ research group, and 11 years later I feel lucky to have had that opportunity.

What do you see as an important emerging area of ecohydrology?
I think an intriguing and important next chapter for ecohydrology is the study of urban systems. Cities are creating and reclaiming green space through green stormwater infrastructure, stream restoration, urban agriculture, and redevelopment. Along these lines, I think 2 interesting research challenges will be (1) to develop methods to design and manage the water and nutrient cycles in green infrastructure and (2) to study the trade-offs and synergies between green and traditional grey infrastructure.

Do you have a favorite ecohydrology paper?  Describe/explain.
One paper that had a big impression on me as a young graduate student was Caylor et al. (2005), which quantified the spatial organization of soil, water balance, and vegetation in the Rio Salado river basin in New Mexico. One conclusion of this paper is that the observed spatial pattern of vegetation in the basin appears to be a combination of random processes and the vegetation actively minimizing their exposure to water stress, which depends on their location within the watershed. It integrates several major themes in ecohydrology – random variability, pattern and process, and optimality.
Caylor, K.K., Manfreda, S. and Rodriguez-Iturbe, I., 2005. On the coupled geomorphological and ecohydrological organization of river basins. Advances in Water Resources, 28(1), pp.69-86.
 
What do you do for fun (apart from ecohydrology)?
I try to spend as much time as I can outdoors, either running, hiking, or biking. Since moving near Lake Michigan in Milwaukee, I’ve recently picked up kayaking and sailing. When I’m at home, I like to cook and play guitar and piano. 

Angelica Maria Gomez is a PhD student at the University of North Carolina at Chapel Hill in the Department of Geography.

What does ecohydrology mean to you?
Ecohydrology focuses on understanding how ecological and hydrological processes are connected, what mechanisms are involved, and the feedbacks associated with them at different spatial and temporal scales. 

What are your undergraduate and graduate degrees in?
I completed two professional degrees simultaneously in Colombia: sanitary engineering and computer science engineering. As an undergrad, I was seeking to combine both disciplines when I discovered hydrology and how modelling and software development are integrated as a tool to represent hydrologic processes. Then I did a master’s in environmental engineering where I combined hydrological modelling and spatial database design. Now I am a PhD student in Geography where I also have the opportunity to listen more carefully and discover strategies to integrate ecohydrology to social processes which I believe is a complex area that I would like to explore during my career. 
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How did you arrive at working in/thinking about ecohydrology?
I started thinking questions related to water-land cover interactions at the final stage of my master’s thesis. My research was conducted in a tropical rural and remote region where rapid land use and land cover changes were occurring due to intensification in agricultural and mining practices. I used hydrologic conceptual model’s approach to understand the groundwater recharge of a shallow aquifer. However, lack of data on land use change made it challenging to conceptualize and represent those changes in the model. Later, working on consulting projects in hydrology, I experienced the limitations that neglecting land cover and land use dynamics can cause in the decision-making processes in both, land and water management. Then, I decided I wanted to contribute to reducing these limitations during my PhD, and I found ecohydrology as an integrated discipline. Currently, I am studying the impacts vegetation change due to agricultural practices produce in the hydrologic cycle in tropical settings.  

What do you see as an important emerging area of ecohydrology?   
Understanding the water and energy cycles under scenarios of change: This includes addressing data integration among remote sensing, ground observations as well as combining historical data describing ecosystems and hydrologic processes in different geographic, ecological and hydrological settings.

Do you have a favorite ecohydrology paper?  Describe/explain.
Asbjornsen, H., Goldsmith, G. R., Alvarado-Barrientos, M. S., Rebel, K., Van Osch, F. P., Rietkerk, M., Chen, J., Gotsch, S., Tobon, C., Geissert, D. R., Gomez-Tagle, A., Vache, K., Dawson, T. E. (2011). Ecohydrological advances and applications in plant-water relations research: a review. Journal of Plant Ecology, 4(1–2), 3–22. They present a broad spectrum of the challenges and advances of the discipline. It is a good reference paper to understand how the field has evolved and what are perspectives guiding data collection and data analysis as well as modelling techniques.

What do you do for fun (apart from ecohydrology)?
I enjoy dancing folklore especially from Colombia because it is the one I have more experience with, but I also enjoy learning about music, dance movements and traditions all over the world. Besides dancing, I hike and love going to forested and rural areas.

Dr. Simone Fatichi is a researcher and lecturer at the Institute of Environmental Engineering, ETH Zurich, Zurich, Switzerland.

What does ecohydrology mean to you?
My view of ecohydrology is of an interdisciplinary science that studies the interactions between ecosystems (mostly terrestrial ecosystems) and the water cycle. In this regard, ecohydrology requires expertise in different topics and is a cornerstone discipline to address societal challenges related to climate and land use changes, food security, and sustainable use of ecosystem services.

What are your undergraduate and graduate degrees in?
I obtained my Bachelor and Master degrees in Environmental and Earth Engineering but my curricula was very much oriented toward water-related disciplines as hydrology, fluvial hydraulics, and design of hydraulic infrastructure with a solid background in numerical methods and modeling. Only during my PhD and afterwards, I studied topics as terrestrial ecology, plant physiology, soil biogeochemistry and atmospheric science. While my formal training was mostly in hydrology, through self-education, active research, and collaboration activities, I enjoyed very much to cover the gaps that link my original background with these disciplines.

How did you arrive at working in/thinking about ecohydrology?
As a young boy, I had always been captivated by meteorology and extreme weather phenomena. While I did not pay much attention to this inclination in my undergraduate studies, very likely this passion was revived by the study of the water cycle. After having started a PhD in hydrology, I soon discovered that to properly understand and quantify the water cycle, evaporation and transpiration are way more important than the limited space devoted to these subjects in old hydrology textbooks would suggest. Having to deal with transpiration, automatically means having to deal with plants.  These alive components, when confronted with the lifeless elements, which are typically the subject of studies in engineering, finally sparked my fascination for water-vegetation interactions, i.e., ecohydrology.

Additionally, while I recognize the “beauty” of simple explanations and parsimonious structures able to highlight the emergence of general governing principles, I am inclined to be attracted more by complexity, by behaviors that can only be explained combining multiple processes. Also in this case, ecohydrology was the perfect venue to direct my interests.  

What do you see as an important emerging area of ecohydrology?
While I think we understand quite well various aspects of water-vegetation interactions observed in the past, there is still a great deal of uncertainty in how water cycle and ecosystems will respond to mutated environmental conditions, as changes in climate (e.g., precipitation, atmospheric CO2 concentration, vapor pressure deficit). Finding innovative ways for studying ecohydrological responses to environmental changes across different scales from the leaf to the globe is probably not a completely new problem but nevertheless extremely important.

Furthermore, I think there will be an increasing attention toward “urban ecohydrology”. There are major concerns related to ecosystem transformations and alterations of water, carbon and nutrient cycles in urban areas, where population is increasing and land-use is changing dramatically. An often-proposed mitigation strategy to counteract negative effects of urbanization on micrometeorology, hydrology, biogeochemical cycle, is the increase of vegetation in cities. There is a critical need to understand and quantify the interactions and associated feedbacks between ecological systems and the hydrological cycle in urban environments.

Do you have a favorite ecohydrology paper?  Describe/explain.
If I have to select a single article, which modified my way of looking at ecohydrology, this is Ivanov et al.,  2008, WRR. I read this article when it was still unedited and I was at the beginning of my PhD. It was an article describing a model, but I was captured by the level of mechanistic representation and description of hydrological and vegetation processes, especially when compared with the large degree of empiricisms in methods I was taught during my studies. For the first time, I realized that we could use conservation of mass, energy, and momentum and reliable parameterizations for a combined modeling of the hydrological cycle and vegetation dynamics.

Ivanov, V. Y., R. L. Bras, and E. R. Vivoni (2008), Vegetation hydrology dynamics in complex terrain of semiarid areas: 1. A mechanistic approach to modeling dynamic feedbacks, Water Resour. Res., 44, W03429, doi:10.1029/2006WR005588.
 
 
What do you do for fun (apart from ecohydrology)?
I am becoming always more addicted to traveling. I travel often for work related reasons, but I enjoy taking a few additional days, whenever I can, to explore new landscapes, cultures, meet people with different backgrounds. I also enjoy very much sports, such as soccer, cycling, and swimming even though my time commitment in this regard is much less than it should be. 

 Dr. Naomi Tague is an Associate Professor of Hydrology in the Bren School of Environmental Science and Management at the University of California - Santa Barbara.  She is also Director of the Tague Team Lab for Ecohydrology and Informatics.  Twitter: @TagueTeamLab | ​@naomi_eco_hydro

What does ecohydrology mean to you?

Ecohydrology studies the intersection between biology and hydrology. I focus on plants and try to build models of how much water plants use but also how much water plant need and what happens to plant physiology and ecosystem structure and function when water availability change.

What are your undergraduate and graduate degrees in?

My undergraduate degree was in Systems Design Engineering (at the University of Waterloo). Learning to think about ‘things’ as systems and how to use mathematics to describe system dynamics was a great foundation. My graduate degrees were in Geography at the University of Toronto – it was there that I began studying the environment and in particular the spatial and temporal dynamics of ecohydrology.

How did you arrive at working in/thinking about ecohydrology?
 
I started thinking about ecohydrology during my PhD.  During my PhD I spent a lot of time developing a hillslope scale hydrologic routing model that was linked to an ecosystem carbon and nutrient cycling model. I then used this model to look at how forest roads changed the routing of water and what the implications were for downslope forest water use. I didn’t really think about this as ‘eco-hydrology’ at the time – but I did think a lot about spatial patterns of forest water use – I still think about this – and how vegetation water use changes with climate, with urban design, with fire…

What do you see as an important emerging area of ecohydrology?

Innovation in data: new data sets and new ways of using data are changing eco-hydrology.  New high spatial and spectral resolution data from remote sensing – whether it is from drones or satellites, new automated sampling methods, new ways using isotopes or genetic information combined with emerging data science/machine learning techniques – all of this will lead to new insights into ecohydrology.  My sense is this evolution of data-science  will be especially important for enhancing our understanding of plants and how they function – including how they respond to water availability, to climate and, to disturbance.  Plasticity of plant function is still poorly represented in our ecohydrologic models, even our conceptual ones, but this is changing. 

The eco-hydrology of urban environments is also a favorite area of mine – we increasingly live in urban environments – and improving our understanding of ecohydrology in urban systems can help us make cities more sustainable.   
 
Do you have a favorite ecohydrology paper?  Describe/explain.
I really like Asbjornsen, H. et al. (2011), Ecohydrological advances and applications in plant–water relations research: a review, Journal of Plant Ecology, 4(1-2), 3–22, doi:10.1093/jpe/rtr005.  It is just a great review of key themes– and offers the dual ecohydrology perspective that includes both how water impacts plants and how plants impact water.
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What do you do for fun (apart from ecohydrology)?
Like many who study the environment, I hike, bike, swim and play – I love being in the forest. I’ve also have studied tai chi for many years – and really appreciate that I  have  a daily meditative but also physical practice. Music is great – summer outdoor jazz concerts are much fun.  I am also an orthodox jew and truly enjoy the learning from the many teachers I have had and books that I have read on what that means. 

Dr Yannis Dialynas is a Lecturer in the Department of Civil and Environmental Engineering at the University of Cyprus.   Email: ydialy01@ucy.ac.cy

Mark S. Johnson is Professor and Canada Research Chair in Institute for Resources, Environment and Sustainability and Department of Earth, Ocean and Atmospheric Sciences at The University of British Columbia, Vancouver Canada.  Twitter: @ecohydrologist