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.