Dr. Amy Hansen is an Assistant Professor in the ​Department of Civil, Environmental and Architectural Engineering at the University of Kansas.

What does ecohydrology mean to you?
I think of ecohydrology as the study of the interdependence of ecological and hydrological processes. Ecohydrolology accounts for some of the most common feedbacks in a natural system. For example, aquatic plants obstruct the movement of water in streams yet the movement of water also regulates plant growth by changing the supply of nutrients and, in turbid waters, the available light. I really enjoy thinking about positive and negative feedbacks between ecological and hydrological systems and how those might be either dampening or amplifying an external change that is imposed on the overall system.

What are your undergraduate and graduate degrees in?
As an undergraduate, I wanted to design cars to go faster (yeah, I know). To that end, my undergraduate degree is in Engineering and Applied Science from Caltech and my Master’s degree is in Mechanical Engineering from University of Michigan. After 7 years of working in industry, a year-long road trip around the USA and 2.5 years in Peace Corps, I had something of an epiphany regarding how I wanted to use my time and energy and changed direction from the mysteries of the internal combustion engine towards a much more complicated topic; the mysteries of the natural environment. Subsequently, my PhD is in Civil Engineering with an Ecology minor from University of Minnesota, advised by Jacques Finlay in Ecology and Miki Hondzo in Civil Engineering.

How did you arrive at working in/thinking about ecohydrology?
Just before beginning my doctorate program, I was living in Honduras as a U.S. Peace Corp volunteer. In this role, I worked with rural community drinking water organizations who were interested in improving the quality of their water and/or protecting their source watersheds. I was struck by the complete lack of financial resources that made the conventional methods to clean up water, which all have a relatively high associated cost, useless for them. At that time, I was thinking a lot about cheap ways to improve water quality and how poor water quality can impact all organisms, not just humans. I started getting interested in studying the role that vegetation plays in nutrient and contaminant cycling in river networks. It was interesting enough to me that when I returned to the U.S. I left my career in Mechanical Engineering behind to pursue a PhD.    

What do you see as an important emerging area of ecohydrology?
The incorporation of aquatic ecology into water quality models. Aquatic vegetation, floodplain vegetation, and filter feeding organisms can all change hydrological conditions and water chemistry yet are seldom incorporated into water quality models. We represent microbial processes better! For example, filter feeding organisms such as freshwater mussels alter water quality by filtering out suspended particulates. In large enough numbers or in slow enough flow rates, mussels can have a measureable effect on water clarity. I think that experimental researchers recognize that interactions between hydrology and larger organisms can be significant but they are still not yet well incorporated into river network or watershed models.

Do you have a favorite ecohydrology paper?  Describe/explain.
I really like the review paper by Catriona Hurd (2000), “Water motion, marine macroalgal physiology, and production”. This was the first paper I encountered that laid out the interdependencies between the hydrodynamics and the ecology of a system including implications for nutrient and carbon cycling, light availability, productivity and imposed environmental conditions on other dependent organisms within the kelp canopy. In addition, she described eco-hydro connections at a large range of spatial scales which shows how complex some of these questions can be.    

What do you do for fun (apart from ecohydrology)?
I go outside and walk somewhere wild. I bring my binoculars and one of my kids and I see what I can see. Binoculars are great conversation starters – people often stop us and ask what we have seen! I also like to camp, swim, paddleboard and read.  

Dr. Ryan Morrison is an Assistant Professor in the Department of Civil and Environmental Engineering at Colorado State University (Twitter: @ryanrmorrison)

Dr. Esteban Jobbágy is a Professor at the Universidad Nacional de San Luis & CONICET, San Luis – Argentina (-33.292, -66.342).  @ejobbagy

Dr. Jia Hu is an Assistant Professor in the School of Natural Resources and Environment at the University of Arizona.

What does ecohydrology mean to you?
Ecohydrology is a field of research that links hydrological and ecological processes by studying the feedbacks that occur between both components. I am completely biased, but I do believe that some of the most exciting hydrology related research is currently related to ecohydrology.

What are your undergraduate and graduate degrees in?
My undergraduate degree was in Integrative Biology from UC Berkeley.
Graduate degree was in Ecology and Evolutionary Biology from CU Boulder.

How did you arrive at working in/thinking about ecohydrology?
My undergraduate and graduate research interests were mainly focused on plant water and carbon relations. However, as I began collaborating more with watershed hydrologists, I realized how important it was to take a broader, landscape perspective. By focusing primarily on plant water cycling, I had been completely ignoring how water got to the plants in the first place. By recognizing that soil, plant, and atmospheric water cycling were inextricably linked, I began to take a more holistic approach to research and begin to ask more exciting questions.

What do you see as an important emerging area of ecohydrology?
Because I come from a background in ecology, I may view ecohydrology differently than most ‘ecohydrologists.’ The discipline of ecohydrology arose from hydrology, and I would argue that a more accurate description of the field in its current state is ‘hydrological-ecology,’ since hydrology is still very much the main focus. However, the field is rapidly changing and the integration of both hydrologic and ecologic processes is becoming more common.

One of the most exciting areas are research in ecohydrology is our ability to begin describing mechanisms that govern how water moves through complex landscapes (e.g. mountain watersheds), and the subsequent response by vegetation once water becomes available. By moving beyond simply describing patterns of water availability and water use, but testing mechanisms on why water moves or how it is used in a particular way, the field of ecohydrology can truly begin to integrate both disciplines.

Do you have a favorite ecohydrology paper?  Describe/explain.
Most of us are taught that water typically moves from the soil, to the roots, and then to the atmosphere (i.e. SPAC); however, it is becoming increasingly common to find studies that show direct uptake of water from the leaves and the subsequent downward movement of water into trunks of trees. This mainly occurs in foggy or cloudy environments, where cloud water or fog can be a critical moisture source. This ‘wicking’ of occult precipitation from the atmosphere is not only important in regulating plant water status, but it can also being an important moisture source in stream and even ground water (e.g. cloud water input, fog drip, etc.). Thus, my favorite ecohydrology ‘paper’ is not a paper, but a book, titled, ‘Tropical Montane Cloud Forests: Science for Conservation and Management,’ Eds. Bruijnzeel, Scatena, and Hamilton. While the scope of this book is about cloud forests, the perspective that fog and cloud water can be important sources of moisture is quite important. Furthermore, if we begin to lose vegetation from these tropical cloud forests, from either deforestation or ‘cloud-lifting,’ then there may be less precipitation inputs into tropical headwater ecosystems, leading to less streamflow in the lowland tropics, particularly during the dry season. These feedbacks between vegetation and hydrology are tightly coupled in these systems, and offers exciting opportunities for research!
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What do you do for fun (apart from ecohydrology)?
I love being outdoors and working in the field is one of my favorite things to do. When I lived in Boulder, CO and Bozeman, MT, skiing and hiking were my two favorite activities. Now that I live in Tucson, I am trying to take advantage of being able to hike 365 days of the year. I have two kids who are now finally big enough to hike longer distances on their own and it is my goal to explore more of AZ this year. At home, I love to cook, and spending hours on Sunday afternoon cooking a big family meal is a perfect way to wrap up the weekend.

Dr. Amilcare Porporato is the Thomas J. Wu ’94 Professor of Civil and Environmental Engineering and Princeton Environmental Institute at Princeton University.

Aurora Kagawa-Viviani is currently a PhD candidate with Thomas Giambelluca in the Department of Geography and Environment at the University of Hawaiʻi at Mānoa. 

​Dr. Paulo Tarso S. Oliveira is a Professor of Hydrology and Water Resources at the Federal University of Mato Grosso do Sul (UFMS), Brazil. 

What does ecohydrology mean to you?
In my vision, ecohydrology is a way to better understand the environmental systems dynamics, where hydrological and ecological processes are investigated by an interdisciplinary and integrated approaches. Water is the link between such processes, in which hydrological processes influence and provide feedbacks on the aquatic and terrestrial ecosystem dynamics and vice versa. Furthermore, human activities have altered the ecosystems and water fluxes; therefore, a better comprehend of ecohydrology is crucial to help us to keep a balance between the water-related uses and consequently the human life.
 
What are your undergraduate and graduate degrees in?
I was born in Brazil in 1985 and received both my BSc degree in Environmental Engineering (2009) and MSc degrees in Water Resources (2011) at the Federal University of Mato Grosso do Sul (UFMS), Campo Grande - MS, Brazil.
My Ph.D. in Science - Hydraulics and Sanitary Engineering was obtained in 2014 at the University of São Paulo (USP), São Carlos - SP, Brazil. I also worked as a visiting researcher (2013-2014) at the United States Department of Agriculture (USDA-SWRC) and at the University of Arizona, Tucson, AZ, USA.
 
How did you arrive at working in/thinking about ecohydrology?
When I was a child, I usually spent all holidays on my grandfather’s farm. In the back of the farm’s house there is a stream that for several years was used to generate energy (small-scale hydropower) and where my dad and uncles learned to swim. However, the small-scale hydropower stopped working and I could not swim in this stream because the streamflow was too low, the sediment transport compromised the water channel, and the water quality was not good. Thus, like as any child I asked several questions for my dad, such as: Why can’t I swim? What is going on with the water? Why is the stream too shallow? This has never left my mind!! During my PhD I could study and respond to all of these questions, and I can say I did it studying ecohydrology. One of the main goals of my thesis was to obtain a better understanding of the mechanisms of hydrological and soil erosion processes approaching aspects of the relationship among hydrology, human activities, and the environment. To achieve that, I worked with different scales (plots, watershed and continental) and data sources (experimental field, laboratory, and remote sensing).
 
What do you see as an important emerging area of ecohydrology?
I consider an important emerging area is to better understand ecohydrological processes, and its response to changes, in different spatial-temporal scales. For instance, in a recent study we found a water provisioning improvement in a tropical watershed through payment for ecosystem services based on soil and water conservation practices and vegetation recovery. However, we need to know if the same approach can work in a similar way for different spatial scales (local-regional-continental), climate, and vegetation conditions.

In addition, more investigations are needed considering a catchment coevolution approach, where we can investigate how climate, soils, vegetation, and topography have coevolved during the past and how they might do so in the future. This approach is important to explain catchment's features and functions, and to evaluate the most vulnerable and resilient catchments considering global or regional changes.

Another emerging area that I can point out is an ecohydrological approach with solutions to guarantee the food-energy-water-ecosystem security. It is motived because global population have grown and changed the standards of living promoting an increase of the demand for clean water, food, and energy to unprecedented levels. In addition, we have grappled each year across the globe with the climate change effects, mainly longer-term droughts and more-intense floods. Therefore, new insight in ecohydrology will be needed toward a better solution for these challenges.
 
Do you have a favorite ecohydrology paper?  Describe/explain.
It’s really hard to pick just one. I can cite important ecohydrology papers for me, such as: Rodriguez‐Iturbe (2000), Rodriguez‐Iturbe et al (2009); Newman et al (2006), among others. However, I would like to highlight here the papers by Orellana et al (2012) and Troch et al. (2013). The first one, is a great review paper providing the state of knowledge on groundwater‐dependent vegetation. This paper helped me to understand how groundwater levels might determine vegetation composition/density or vice versa. The second one, shows a strong interaction between climate, vegetation and soil properties that lead to specific hydrologic partitioning at the catchment scale. I like this paper because it helps us summarize different catchment features in a simple and predictable outcome of hydrological partitioning. This paper is really useful to understand past and future catchment coevolution and it is a theme that I currently study.
 
What do you do for fun (apart from ecohydrology)?
It is a good question; I can say that it has been changed during my life. Some years ago, I could say that it is working out, running, swimming, playing soccer, or any other sport... However, currently with two little daughters (Marina: 2 years and half; Milena: 23 days) my life is much busier, but sweeter and fun.  Now , I spend my free time with my wife and daughters doing kids things, e.g. playing dolls, swimming sometimes (Brazil is really hot), and visiting parks or playgrounds!

Dr. Pamela Nagler is a Research Physical Scientist with the USGS Southwest Biological Science Center. She resides in Tucson, AZ. 

Dr. Kim Van Meter is transitioning from a post doc position at University of Water Loo to an Assistant Professor position at the University of Illinois at Chicago in January 2019.    Twitter: @VanmeterKVM

What does ecohydrology mean to you?
For me, ecohydrology is about seeing the connections between systems.  The intersecting disciplines of ecology and hydrology are, of course, built into the word “ecohydrology.” As the field has grown, however, there have been further crossovers and synergies to include a range of different domains, from geochemistry to economics and sociology. To study ecohydrology is to study feedbacks between systems, the impacts of hydrology on ecosystems, of ecosystems on hydrology.  As an ecohydrologist, I ask questions about how humans interact with water and the environment, and how water systems and ecosystems coevolve with human systems.
 
What are your undergraduate and graduate degrees in?
My educational background has been a winding road!  My undergraduate degree was in Literature.  I have two master’s degrees, one in Organic Chemistry and another in Environmental Engineering.  My Ph.D. is in Earth and Environmental Sciences.
 
How did you arrive at working in/thinking about ecohydrology?
I came to my interest in water and water quality from a very practical perspective.  I was traveling in Haiti, where I adopted my son, and was devastated by the death of two young babies at my son’s orphanage due to contaminated water.  I became determined at that time to build a career that expanded beyond the lab to include larger interactions between science and the environment, between human and natural systems. From that point, my interests and my research grew to encompass a range of questions about human impacts on water quality and about feedbacks between water quality and ecosystem health. I think that these kinds of questions and concerns place me squarely in the middle of the new and growing science of ecohydrology.
 
What do you see as an important emerging area of ecohydrology?
I see urban ecohydrology as an exciting new frontier.  Cities in the 21st century are growing quickly—it has been predicted that by 2050 approximately 65% of the developing world and 85% of the developed world will be living in urban areas. As noted by Diane Pataki, urban settlements are one of the few ecosystems on earth that are actually increasing in extent. Accordingly, there are range of important research questions for the urban ecohydrologist. I am particularly interested in the ways in which cities alter both regional and global-scale nutrient cycling. As the built environment increases in extent, it will be crucial to understand how cities mediate the flow of water, nutrients, and a range of contaminants across the urban/suburban/rural continuum.
 
Do you have a favorite ecohydrology paper?  Describe/explain.
Although it’s difficult to pick a favorite paper, one that has been influential in my thinking is a 2014 paper led by Peter Groffman on the “Ecological homogenization of Urban USA.” 
In the paper, the authors explore the urban “homogenization” hypothesis. In other words, they ask the question, does urban land use exert a homogenizing effect across urban areas? Is a Phoenix lawn more similar to a Baltimore or a Minneapolis lawn than to the Sonoran Desert ecosystem surrounding the city.? The findings of their work are important, as they suggest that while decisions about things as seemingly trivial as suburban lawn management may be individual decisions, they are actually tied to broader forces, from social structures and socioeconomic status to national-scale marketing.  Because human behavior, like the biophysical behavior of natural systems, is strongly shaped by a panoply of broader forces, we are able to develop a theory and science of human habitats. From this point, we can move forward to understanding complex feedbacks between cities, water, and ecosystems.
 
What do you do for fun (apart from ecohydrology)?
My dog Darcy (named after the Darcy equation, of course) is a great source of fun and entertainment.  I’ve also recently become obsessed with escape rooms.