​Dr. Rebecca (Becca) Barnes is an Associate Professor at Colorado College in The Environmental Studies Program. You can follow her on Twitter @waterbarnes.

Dr. Alejandro (Lejo) Flores is an Associate Professor at Boise State University in the Department of Geosciences.  He directs the Lab for Ecohydrologic Applications and Forecasting (LEAF!) at Boise State.  Follow him on Twitter @HydroLejo.

What does ecohydrology mean to you?
I marvel at the way that terrestrial vegetation couples the global water, energy, and carbon cycles. Right now, amidst the global COVID-19 pandemic, I’m preparing a few short video lectures for my sophomore-level students in Water in the West aimed at illustrating how evapotranspiration connects these three global cycles and underscoring how fascinating that is. Here’s the link to the playlist, for those interested. To me, the first time I saw that in Fatih Eltahir’s hydrology class my mind was blown. It’s something really profound and underscores the centrality of ecohydrology in a changing climate.

I’m also fascinated by the ways and mechanisms through which humans influence those cycles through water and land management activities. A lot of my contemporary work involves modeling human activities in the landscape as dynamically coupled to natural systems and other humans. We seek to use modeling techniques like agent based models to allow human actors to directly influence the land by, for example, cutting down trees or diverting water and then to capture the ramifications of those actions in ways that can be “felt” by those human actors at a later time.

What are your undergraduate and graduate degrees in?
I got a BS in Civil Engineering from Colorado State, and then stayed for an MS in River Hydraulics from CSU. I did my PhD in Hydrology at MIT with Rafael Bras. In that time as a graduate student I was very fortunate to be exposed to amazing classes that included aquatic ecology, all kinds of fluids and hydrology classes, plant physiology, geomorphology, and also data assimilation and modeling.​
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How did you arrive at working in/thinking about ecohydrology?
As an MS student with Brian Bledsoe I became fascinated with the classical papers of Hack (1957) and Hack and Goodlett (1960) on the influence of vegetation on landforms. At the time, my work focused on trying to investigate watershed-scale indicators of topography, vegetation, land use history, and soils/lithology that might provide insight to reach-scale ecosystem form. It was work oriented towards providing a template for providing geomorphic and ecological context for stream habitat assessments. 

When I was at MIT I was amidst colleagues like Valeriy Ivanov and Daniel Collins were really trying to push the envelope in modeling some key complexities like the influence of hillslope asymmetry on vegetation and water, energy, and nutrient cycles. That was really when I developed an appreciation for models as not simply tools to predict outcomes, but as tools to explore the ramifications of our state of knowledge – to be able to use models to actually reveal things about how the world works that we should be able to observe in nature.  

What do you see as an important emerging area of ecohydrology?
I think better integrating and representing in models the ways that humans influence ecohydrologic systems and the way that those systems respond and ultimately influence human behavior. I see this as critical for ultimately allowing us to manage ecosystems in a changing world, as well as a mechanism to allow us to provide better information to land and water managers. 

Do you have a favorite ecohydrology paper?  Describe/explain.
Again, Hack (1957) and Hack and Goodlett (1960) were really so influential for me. I read them as an MS student in the way that some people read On the Road by Jack Kerouac. As a PhD student the sequence of three papers Plants in water-controlled ecosystems: active role in hydrologic processes and response to water stress by Ignacio Rodriguez-Iturbe, Amilcare Porporato, Francesco Laio, and Luca Ridolfi were sort of the epicenter of discussion amidst many of my cohort at the time. More contemporarily, I’m a big fan of my friend Abby Swann’s work. She just has such elegantly designed numerical experiments. 

What do you do for fun (apart from ecohydrology)?
​Living in Boise and being an Earth scientist, I love the outdoors. The foothills are minutes away on my bike and Idaho’s wilderness only a couple hours away by car. I enjoy introducing my wife and my two little humans to nature and the Earth.

Dr. Susana Alvarado-Barrientos is an Associate Professor at the Instituto de Ecología A.C., which is a Mexican public research institute.

What does ecohydrology mean to you?
Ecohydrology to me, is the integration of ecology and hydrology. It is an effort to holistically study and understand the magic of the planet, which is contained in water (as Loren Eiseley wrote and I totally agree). I like to tell my students to think about ecohydrology as the study of the incredible journey of water molecules around and around the planet, through the atmosphere, as part of clouds and raindrops, through the soils, rocks, rivers, plants, oceans, etc., etc. …and how the journey of all the water molecules modify the paths that they take. As one of my hydrology professors told us, we need imagination to pursue the study of water… I´d like to add that we need double the imagination to pursue the study of both ecology and hydrology together. Personally, it also means a journey: from my home country Guatemala, to Amsterdam, Manaus, Mexico, Iowa, New Hampshire and, so far, back to Mexico.

What are your undergraduate and graduate degrees in?
My undergraduate degree is in Forest Engineering from the Universidad del Valle de Guatemala. I have a MSc degree in Hydrology with a specialization in Ecohydrology from the VU Universiteit Amsterdam. And, I have a PhD in Environmental and Earth Sciences from the University of New Hampshire (but I did two years of the Ecology, Evolution, and Organismal Biology PhD program in Iowa State University before my adviser – Heidi Asbjornsen- moved to UNH).

How did you arrive at working in/thinking about ecohydrology?
After I graduated, I worked at the Sierra de las Minas Biosphere Reserve in Guatemala, on a project setting a water fund to involve different water users and stakeholders in upstream cloud forest conservation. Reading as much as I could about the forest-water links for this work, it became obvious that not a lot was known about the hydrology of tropical montane ecosystems. I don’t remember exactly how, but I came across the research that L.A. (Sampurno) Bruijnzeel´s group and collaborators were conducting in a Costa Rican cloud forest. It took a couple of emails to get me completely hooked on the idea of pursuing a MSc degree in Ecohydrology. I was fortunate to be part of one of the best hydrology graduate programs, having such great professors who not only taught theory in the classroom, but also application and techniques in the field. The faculty had super interesting projects in many places, so I was fortunate to go to Manaus for my master´s thesis field work (supervised by Sampurno Bruijnzeel and Maarten Waterloo). I helped out a doctorate student (Fabricio Zanchi) who´s project was hosted at LBA, so I was able to climb flux towers in the rain forest and wonder about the magnitude of the forest´s water flux towards the atmosphere. My thesis was on evapotranspiration estimates of an Amazonian heath forest (Campina)… which is out of this world by the way…how do these trees manage to live out of white sand?!

After that adventure I was invited to join a multidisciplinary team in Mexico to study cloud forest ecohydrology, as a doctorate student under the direction of Heidi Asbjornsen. I was joining a dream team, and back then I was not fully aware of this. Other PIs were Todd Dawson, Jeff McDonnell, and Sampurno Bruijnzeel. Friso Holwerda and Lyssette Muñoz-Villers were postdocs, and Greg Goldsmith was the other doctorate student. Many others were also involved, and I feel completely humble and honored, as I think back, to have been part of many discussions and to learn from these brilliant scientists. The two-water worlds hypothesis was in the making, for example. This project was the beginning of a long friendship and work collaboration among us. After I finished grad school, I came back to Mexico for a postdoc with Friso Holwerda, who was already at UNAM. Thanks to all these opportunities, I was able to set roots here. Now I am living the dream in Xalapa (lower montane cloud forest and coffee plantations altitude): working towards developing my research interests, collaborating on diverse projects, and teaching ecohydrology at the graduate level.

What do you see as an important emerging area of ecohydrology?
The hydrological functioning of ecosystems has been always a big area of ecohydrology, so emerging from that, I think questions about water redistribution and complementary/competitive water use of coexisting plants are still interesting and much is still unknown. I just recently came across, and started to be involved with, questions about the distribution of water among plants that create inter- and intraspecific root networks, such as mangrove species. These interactions are quite interesting and long-standing questions of ecology arise, such as mutualism in the face of very hostile environments. All the research stemming from the two-water world hypothesis is still a fruitful area of ecohydrology. Particularly interesting, but also very important for sustainable land management, are questions about complementary water (and nutrients) use of coexisting plants in biodiverse agroecosystems. The more is known on how different crops interact with other plants to the extent of sharing limited below-ground resources, the more we can contribute to agroforestry planning and increasing biodiversity in agroecosystems while maintaining productivity of food and other goods.

Another important area of ecohydrology has always been the land use change effects on hydrology and climate, which requires thinking not only on biophysical systems but on socio-ecosystems. Particularly and currently interesting to me, are the developments on how disruptions to hydrological connectivity in coastal ecosystems have impaired their functions leading even to mortality (like for mangroves), and how restoration of hydrological connectivity can be effective to restore vegetation in massively degraded zones. Also, as more and more measurements of land surface-atmosphere interactions are done and synthesized from tropical and coastal ecosystems (which are still under-represented in global measurements), fascinating things will be learned to fill gaps needed to validate models related to carbon allocation, carbon and water fluxes and the role of vegetation on modulating the climate at different scales.

After teaching ecohydrology to graduate students with different areas of specialization in ecology (some unrelated to ecohydrology), students mentioned, to my surprise, that the most interesting thing they learned was that vegetation was not only shaped by the environment, but that in fact, vegetation was very much involved in shaping the environment. So, I think that we have a lot more work to do in the realm of science outreach, not only to the general public, but also among other disciplines.
 
Do you have a favorite ecohydrology paper?  Describe/explain.
This is a hard one. I have always admired how my professors write, so I am a bit biased to have their work as some of my favorites. I have a couple of favorite books, and on top of the list is “Forests, water and people in the Humid Tropics” edited by Mike Bonell and L.A. (Sampurno) Bruijnzeel. They did such a great and complete work. It is a compendium of a lot of aspects of the hydrological functioning of tropical forests and the hydrological impacts of land use change. The book is not only technical aspects but also reviews complex societal/political issues in the tropics. There has been a lot of advancement on the knowledge of ecohydrology of tropical forests since the book was out, but it is still largely relevant.

What do you do for fun (apart from ecohydrology)?
I have a four-year old, so everyday I get to play with whatever is exciting to him (mostly involving superheroes, rescue team, riding a bike downhill), reading to him, and trying to come up with answers to some really intriguing questions on how everything works or what does something mean. I also enjoy trekking around nearby towns and parks with my family. 

Caitlin Eger is a doctoral student in Civil and Environmental Engineering at Syracuse University.  You can find her on Twitter: @Ecologentsia.

What does ecohydrology mean to you?
I think of ecohydrology as the physical or hydrologic features, conditions and processes that causally influence local ecological structure. This definition is complemented by a somewhat less-used term, hydroecology, which describes the reverse effect—that is, when ecological features are the cause of a locally specific hydrologic regime. A good example of an ecohydrologic feature is a seasonally high water table in a location where the temperature and terrain create the right conditions for forested ephemeral pools to exist in early spring, thereby creating breeding habitat for salamanders. Conversely, a hydroecological feature might be a cloud forest in which transpiration from the forest (but not precipitation) is driving humid, foggy conditions.

What are your undergraduate and graduate degrees in?
I completed a B.S. in Environmental Science and Chemistry at Juniata College, a small liberal arts school in central Pennsylvania. The college’s domestic field courses, study abroad program, and field station on Raystown Lake offered formative field experiences in my environmental science education. At the time, the Juniata chemistry department taught an organic-first curriculum for all STEM majors – Dave Reingold and Richard Hark made the material so interesting that I added chemistry to my environmental science major.

Later I completed a master’s in the Food, Agricultural Biological and Ecological Engineering department at Ohio State University. At OSU I completed coursework with three excellent ecological engineers, Jay Martin, Andrew Ward and Bill Mitsch. Andy Ward’s Environmental Hydrology textbook is one I have used regularly since undergrad and still reference. My master’s thesis looked at nutrient retention in suburban rain gardens, which had been retrofitted into a local neighborhood.
I am now completing my dissertation at Syracuse University in Civil and Environmental Engineering, advised by a biogeochemist, Charles Driscoll, and a hydrologist, David Chandler. My dissertation work examines how engineering design affects green infrastructure performance in the urban environment.

How did you arrive at working in/thinking about ecohydrology?
Like 350,000 other Colorado public school children, I attended Outdoor Lab for a week to learn about environmental science in the Rocky Mountains as a sixth grader. Seven years later, I took a gap year between high school and college and returned to Outdoor Lab as an intern. One of my intern responsibilities included teaching a three-hour trail course that introduced 6th graders to very basic ecology and hydrology principles. The course included hiking to north and south-facing sites in the same valley and having the students take field observations of relative humidity and temperature using a sling psychrometer. Teaching this course repeatedly throughout the water year provided a chance for me to observe firsthand how physical conditions, such as aspect, moisture and temperature could affect soil formation, freezing, snow cover, species density and biodiversity.

What do you see as an important emerging area of ecohydrology?
I am dedicated to the idea that ecological engineering is an important emerging area of ecohydrology, since it relies upon the transfer of ecohydrologic discovery into applied engineering problems. The ecohydrologic processes we observe in natural systems are fascinating, but the field of traditional civil engineering is long overdue for an upgrade that includes understanding of how structures influence hydrology and ecology in the built environment.

Do you have a favorite ecohydrology paper? Describe/explain.
I’d like to suggest a favorite book – Soil Physics with Python: Transport in the Soil-Plant-Atmosphere System by Marco Bitelli, Gaylon Campbell and Fausto Tomei. I have been slowly working through the exercises in this book and found it a great way to learn Python. I was so excited to see the second edition published this year that I requested it as a birthday gift.

What do you do for fun (apart from ecohydrology)?
To reduce stress in the coronavirus era, I’ve been savoring time with my family, sprouting seeds for my garden, making pavlova, and playing Zoom trivia with my colleagues every Thursday.

Dr. Daniel Bunting is a Geospatial Biologist at the U.S. Fish and Wildlife Service (USFWS) in Austin, Texas.

 What does ecohydrology mean to you?
I have always thought about ecohydrology in the opposing context of how a hydrologist would define hydrology. While a certified hydrologist might improve a flood control project using complex mathematical equations in a world of engineered cement basins and trapezoids, an ecohydrologist might think about recharge basins and how soil and vegetation would impact runoff via infiltration and evapotranspiration (ET). While I couldn’t imagine going the engineering route and conquering the complex courses and math that go hand-in-hand with those degrees, I do get a chuckle when engineers or hydrologists scratch their heads when having to learn about plants and their influence on roughness and ET. That said, ecohydrology is complex in and of itself, and those studying it make contributions that are greatly needed to bridge the gap between the disciplines of hydrology and natural resources.

What are your undergraduate and graduate degrees in?
My undergraduate studies included General Biology with a minor in Wildlife Science. After five years as an entry-level biologist, I returned to school and studied Ecohydrology and Watershed Management (MS, PhD) in the School of Natural Resources and the Environment at the University of Arizona (Go Cats, Bear Down!) within the Papuga Research Lab. I minored in Remote Sensing and Spatial Analysis and acquired a Global Information Systems Certificate along the way.

How did you arrive at working in/thinking about ecohydrology?
Growing up in Lake Havasu, AZ along the Lower Colorado River, I’ve always had an appreciation of water flowing through the desert. Grad school reaffirmed how important riparian corridors are in dryland systems. Half of my dissertation was in applied restoration where I evaluated competition of cottonwood, willow, and tamarisk growth under different irrigation regimes. The other half involved correlating ET flux tower data to remote sensing products to scale ET estimates across vegetation gradients. Both required knowledge of how and why water moves from the earth’s surface to the atmosphere. The easiest way for me to understand the hydrological cycle was to imagine that rain only has a few options after it reaches the surface: it goes up (ET), down (infiltration/storage), or sideways (runoff). The majority of my research looked into how moisture went back up into the atmosphere. By partitioning my research into that bucket, I could then begin to understand how (E)vaporation─direct return of water to the atmosphere from the ground, canopy, or surface water─and (T)ranspiration─water moving from the soil through a plant as the conduit and back to the atmosphere via stomata─really work. Sure there are species-specific implications with overall canopy cover, leaf area, age, salinity tolerance, soil moisture availability, etc, but you just take it one step at a time, and answer one question at a time.     

What do you see as an important emerging area of ecohydrology?
For years, the water balance has been difficult to resolve due to high spatial heterogeneity in soils, vegetation, and climate patterns across regions. The evolution of remote sensing products and increased availability and accessibility to multispectral imagery of higher spatial and temporal resolution has resulted in an explosion of applications relevant to managing and monitoring natural resources. Modeled precipitation data has come a long way and an increased network of precipitation gages and long-term datasets allow for higher calibration across ecosystems. Combined, data availability and increased computing power has opened the door for modeling and studying ecohydrological patterns at larger scales to inform water budgets, address human needs, but most importantly in our field, to assess impacts to natural resources; with an aim to preserve, conserve, enhance, rehabilitate, or restore our natural ecosystems for the benefit of native fish and wildlife.

Do you have a favorite ecohydrology paper?  Describe/explain.
Nope, I’ll have to simply give a shout out to another graduate committee member, Pamela Nagler (USGS), who has an onslaught of journal articles focusing on plant/water-use relationships; several of which use remote sensing to evaluate water loss or water savings in the context of tamarisk control/invasive species management, riparian revegetation, or restoration monitoring.

What do you do for fun (apart from ecohydrology)?
​My years of trail running have given way to mountain biking. I can cover more distance while identifying more plants, birds, and other critters along the way; all while staying vertical. My wife Lindsey and I have an amazing 3-yr old toddler who demands most of our time, especially while sheltering-in-place and practicing social distancing during this Covid-19 pandemic. When the dust settles, we will get back outdoors to camp, hike, and enjoy as much nature as possible!

​Dr. Doerthe Tetzlaff is a Professor in Ecohydrology at the Humboldt-Universitaet zu Berlin and Head of Department “Ecohydrology” at IGB Leibniz Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany. She is also a Fellow of AGU, a Fellow of the Royal Society of Edinburgh and an Honorary Fellow of GSA. 

What does ecohydrology mean to you?
The integrating concept of ecohydrology fascinates me. For me ecohydrology is the connection between landscapes and riverscapes, i.e aquatic and terrestrial ecohydrology. It is interesting to see how separated the aquatic and terrestrial ecohydrology communities often still are and operate. To be able to understand what happens in our rivers and lakes we - of course - have to understand the processes in the landscape; both landscape and riverscape are closely intertwined. So, to me ecohydrology means to better understand the spatio-temporal variability of the aquatic and terrestrial ecohydrological connections and the “behaviour” of catchments.
 
What are your undergraduate and graduate degrees in?
I have an undergraduate degree in Geography from the University of Potsdam, Germany, a MSc (or Diploma) in Physical Geography and Landscape Ecology from the University of Hannover, Germany. I did my PhD in Hydrology at the University of Freiburg, Germany. So, I have quite a “blue water” background but since my Postdoc I got to know about “green water” fluxes as well.  
 
How did you arrive at working in/thinking about ecohydrology?
During my PhD I conducted an ecohydrological assessment of urbanization effects on discharge regimes. However, I really got pulled into (aquatic) ecohydrology when I started my postdoc in Scotland when I saw my first Atlantic salmon (Salmo salar) jumping up large rocky barriers back to its spawning ground which was simply amazing. So my first ecohydrological work examined hydraulic and hydrological influences on the ecology of different life stages of Atlantic salmon. I then extended this work to explore the utility of the concept of connectivity between landscapes and riverscapes, showing the effects of catchment-scale hydrological processes on the migratory movement of adult salmon. In parallel with my aquatic ecology research, I became increasingly involved in stable isotope hydrology that has sought to understand the influence of landscape controls on (eco)hydrological flow paths and the transit times of water in different catchments, as well as the interlinkages with and effects on the terrestrial and aquatic biota. Recently, my work centered on contextualizing findings more broadly into the relationship between structure and function of catchments; their response to climate change and how the ecohydrological implications differ across catchments.
 
What do you see as an important emerging area of ecohydrology?
There are still so many ecohydrological processes which we are just beginning to understand. Some of these processes – which might occur at very high temporal resolution or high frequency – we might even just begin to be able to actually measure with new sensor and in-situ technology. But one of the big emerging research areas I see is the ecohydrology of urban areas. Urbanization is increasing world wide, and urban systems are even more complex than “natural” catchments. Urban systems are “artificial catchments”, which have profoundly different dynamics compared to natural systems. Monitoring is often limited in urban settings (due to vandalism and access limitations). So, understanding ecohydrological couplings and connectivity in an urban context; that’s still a major emerging area in my point of view. There is still so much to learn and find out about urban ecosystems.
 
Do you have a favorite ecohydrology paper?  Describe/explain.
My favorite ecohydrology paper which I still cite very often is an Invited Commentary published by Catherine Pringle in Hydrological Processes in 2003 (already!) on “What is hydrologic connectivity and why is it ecologically important?" It nicely explains the concept and need of interdisciplinarity and also highlights emerging issues of global concerns – many of them still very much hot topics still today.
 
What do you do for fun (apart from ecohydrology)?
Fortunately, our area of research always gives us a wonderful “excuse” to spend a lot of time in and with nature and water – and that’s what I love to do for fun. I love running and road cycling. Now, we are a couple of two professors in two different countries and our family splits their time between our new home in Berlin and Scotland. Berlin is such a green big city, with loads of green spaces and lakes and rivers to swim in (and wonderful to study urban ecohydrology). And Scotland of course has its mindblowing landscape of rivers and mountains. I feel extremely lucky to be able to have the best of these two worlds. Yoga and Pilates also is fun. 

Dr. Alexandra Konings is an assistant professor in Earth System Science at Stanford University/

What does ecohydrology mean to you?
Insofar as hydrology is the study of the distribution and movement of water, ecohydrology, at its simplest, studies how water’s distribution affects ecosystems and vice versa how ecosystems affect water. That is reductionistic, but I take a very broad view of this definition – soils, the atmosphere urban landscapes, anthropenic influences, etc fit into ecohydrology as well. Perhaps more broadly, I think of ecohydrology as a relatively interdisciplinary study of how water, plants, and living things all are coupled and affect each other in multiple, usually interactive, ways.

What are your undergraduate and graduate degrees in?
I have an undergraduate degree in Civil and Environmental Engineering from MIT, a MS in environmental science from Duke University, and my PhD is also in environmental engineering from MIT.

How did you arrive at working in/thinking about ecohydrology?
I studied environmental engineering as an undergraduate after getting disillusioned from my original physics major. At the time, hydrology seemed to me to be the most ‘physics-y’ corner of environmental engineering…but a few years of undergraduate study later, I found myself wishing I knew more about the biological aspects of plants and how that would affect my view of what hydrology was. I spent a few fun years working with Gaby Katul at Duke on a variety of projects across hydrologic fields. While I didn’t think of myself as doing ecohydrology at the time, I absorbed some of the great ecohydrological thinking being done around me in the Nicholas School of the Environment. However, I really missed Cambridge and Boston, so I returned to MIT after a few years. After a PhD with Dara Entekhabi that was largely focused on my first love of microwave remote sensing, I’ve enjoyed bringing my fascination with plants back and applying the tools of remote sensing to various ecohydrological problems.

What do you see as an important emerging area of ecohydrology?
Alfredo Huete answered similarly a few months ago, but one exciting emerging area is the use of all the new satellite data that are starting to come online. That includes totally new types of data from new flagship NASA sensors like GEDI, (canopy height and biomass), TROPOMI (solar-induced fluorescence), SWOT (surface water extent and estimates of discharge), or even ECOSTRESS (land surface temperature and thus, estimates of ET). Cubesat data at few-meter resolution have also become dramatically more available in recent years. This is all very exciting and there is lots of great science to be done. But there is such a rapid increase in data availability that we will need to develop new ways of interacting with and analyzing this exponential increase in data. It will be important to learn from ‘big data science’ while still saying grounded in biogeophysical understanding. While doing so, as a community, we will especially have to reckon with the fact that we have a wealth of remote sensing observations about aboveground processes, but that belowground process remain mostly unseen by satellites.
 
Do you have a favorite ecohydrology paper?  Describe/explain.
This feels like picking the best day I’ve ever had. There are so many great ones. I honestly can’t pick a single most favorite, but I’ll highlight a relatively recent one that I really like and isn’t as commonly appreciated: Crow et al’s 2015 GRL paper: “Robust estimates of soil moisture and latent heat flux coupling strength obtained from triple collocation”. This paper modifies a technique known as ‘triple collocation’ to figure out how strongly coupled soil moisture and evapotranspiration are across different Fluxnet sites….but with a careful accounting for the unknown random errors in measurements that turn out to distort a naïve calculation of correlations. It’s extremely elegant and satisfying.
 
What do you do for fun (apart from ecohydrology)?
I am glad this question points out that ecohydrology *is* a lot of fun! I also try to regularly participate in outdoor activities: hiking, biking, and occasionally climbing. But mostly I spend a lot of time with friends and family. Like many junior faculty at Stanford, I live on land leased from the university to reduce costs in the expensive Silicon Valley area. That feels a bit strange philosophically, but a positive side effect is that many of our closest friends live only about a minute’s walk away – making it easy to spend time with a close community. 

Dr. Anne Jefferson is an Associate Professor at Kent State University in the Department of Geology (@highlyanne on Twitter).

What does ecohydrology mean to you?
To me, ecohydrology is the study of the interactions between living systems and the hydrosphere. These interactions could be happening within or because of a single plant, animal, or microbe or they could be ecosystem-scale or watershed-scale processes. Ecohydrology synthesizes concepts from hydrology and ecology to approach problems that can’t be understood from a single disciplinary perspective. 

What are your undergraduate and graduate degrees in?
I have an undergraduate degree in Earth and Planetary Science from The Johns Hopkins University, a MS in Water Resources Science from the University of Minnesota, and a PhD in Geology from Oregon State University.

How did you arrive at working in/thinking about ecohydrology?
To some extent, I blame my mother! She is a retired plant ecologist, and she worked in environments ranging from salt marshes and floodplains to goat prairies (really neat dry prairie ecosystems found on south facing slopes along the Upper Mississippi River valley). So I grew up being exposed to ecological ideas and how ecosystems interacted with water. My own research adventures began with the 1993 flood on the Mississippi River, and my bent is more physical processes than ecology, but the interactions between the physical and ecological are everywhere I look.

For the last 10 years, my research has focused on water in human-altered environments, especially cities. I look at how stormwater management and environmental restoration alter partitioning of flow between the surface and subsurface, change flow regimes and erosion patterns, and alter ecosystem processes. Right now, I have a really cool project in Cuyahoga Valley National Park looking at how a restoration practice called deep ripping might enable reforestation of abandoned mine sites by changing preferential flow paths – and, in turn, how the young trees might start to influence soil development and hydrology as they become more established.
 
But it’s maybe only in the past few years that I’ve come to admit that I am (at least in part) an ecohydrologist. Participating in a HydroEco conference a few years ago really opened my eyes to ecohydrology as a broad tent of perspectives and approaches. I realized that I had a misconception of ecohydrology as this very narrow field, when, in fact, much of what I do could be considered ecohydrology, 

What do you see as an important emerging area of ecohydrology?
I’d be remiss if I didn’t say urban ecohydrology! I think there’s a lot of really cool work starting to be done on hydroecological processes happening in cities – from how disconnecting downspouts alters net primary productivity to how planting street trees can help manage stormwater. That’s just two examples and I think we’re only beginning to scratch the surface of understanding how ecohydrological processes work in urban environments – and how we can use these processes to make our cities greener, healthier, and happier. As we start to weave engineered infrastructure and social systems into our ecohydrology research, I think we’re going to see lots of exciting ideas emerge. 

Do you have a favorite ecohydrology paper?  Describe/explain.
I’ve really been enjoying following the literature on “ecohydrological separation” or the “two water worlds.” These terms capture the idea that trees may not be accessing the same subsurface water as streams do and that when we sample stream water and infer catchment transit times, we may be missing a big piece of the story. I’m hoping that as my National Park trees get older, that I’ll be able to contribute more to this literature myself. But for now, I’ve got to point to the Brooks et al. (2010) paper (https://www.nature.com/articles/ngeo722) that did such a nice job of stimulating a decade of work. 

What do you do for fun (apart from ecohydrology)?
I have two kids (5, 13), a partner, and a dog, and my family and I love hiking. I was on sabbatical in Colorado this fall and it was great to have new trails to explore every week. My 5 year old did 6 miles of gentle grade above 11,000 feet! We also like musical theater, museums, and other cultural activities – as well as just quiet days spent pursuing our own interests at home. 

When I’m not spending time with my family, I really like mentoring students on research projects, creating interactive learning opportunities in my classes, and doing public engagement activities to share my love of science. I’ve also been trying to spend more time volunteering for causes I support. 

Dr. D. Scott Mackay is a Professor in the Department of Geography & Department of Environment and Sustainability at the University at Buffalo. 

What does ecohydrology mean to you?
For me ecohydrology is an expansive concept that has developed in multiple fields and formed a convergence of science around theory and methodology involving the interactions between water and living things. During my research leave last year I dove into the origins and spread of ecohydrology. This exploration took me through several thousand articles spanning more than a century, multiple disciplines, and wide range of spatial and temporal scales. From botanists Dixon’s and Joly’s 1895 theory on ascent of sap in plants, to hydrologist Robert Horton’s 1933 call for more attention to plant-water relations, to Peter Eagleson’s 1982 reintroduction of ecohydrology to hydrologists, to the recent emergence of co-evolution of vegetation and landforms, ecohydrology has a rich and, in retrospect, a straightforward evolution. But ecohydrology emerged in many places, with its earliest mention by name in contexts such as form and function of peatlands, forest decline from soil acidification, and sustainable use of aquatic resources. Regardless of flavor and origin, what underlies ecohydrology is a solid foundation on systems concepts.   

What are your undergraduate and graduate degrees in?
My undergraduate degree was called Biophysical Systems, but it was primarily geomorphology, climatology, a little biology, quite a lot of computer science, and a ton of systems concepts. For my MSc degree, I did physical geography, developing an automated digital terrain analysis system based on early artificial intelligence theory. My PhD was in Civil Engineering, where I developed models on the dynamic interaction between forested vegetation and watershed hydrology. All my degrees were from the University of Toronto.

How did you arrive at working in/thinking about ecohydrology?
I arrived at thinking about ecohydrology in the early 1990s when I was at the start of my PhD program. A post doc in our lab, an ecologist/meteorologist, put me onto the concept of ecological optimality, which helped me connect a lot of disparate ideas and set me on the winding path towards my dissertation on dynamic hydroecological modeling. 

What do you see as an important emerging area of ecohydrology?
I see the belowground frontier as an important emerging area of ecohydrology. While the subsurface interactions between abiotic and biotic processes has been considered a critical zone for a long time, there is a convergence of new sensors, tracer methodologies, and sophisticated biophysical models that collectively make the belowground more transparent. Ecohydrology’s strong foundation on systems concepts will be vital to putting the pieces together to form a coherent belowground picture.

Do you have a favorite ecohydrology paper?  Describe/explain.
For me, the “a ha” moment I had as a graduate student was when I first read Peter Eagleson’s 1982 paper on Ecological optimality in water-limited natural soil-vegetation systems. While this paper has been reinterpreted, built on, sometimes misunderstood, sometimes maligned, but often cited, for me it remains my favorite paper as a tour de force in conceptual thinking. It is always required reading in my graduate course titled “Ecohydrology.”

What do you do for fun (apart from ecohydrology)?
Whenever I have the opportunity I like to hike. Hiking help me take my mind off those things that make it hard to be creative, which helps me think about new concepts, algorithms, etc. Also, a few years ago I rehabbed my stereo turntable and re-engaged with an old hobby of collecting vinyl records and listening to music as whole creative entities rather than lists of songs in a digital playlist. 

​Dr. Lauren Lowman is an Assistant Professor in the Engineering Department at Wake Forest University.