AGU Ecohydrology - Blog: Adding our Leaves

AGU Ecohydrology

MEET A LEAF: DANI OR

11/18/2019

Dr. Dani Or is a Professor of Soil and Environmental Physics at ETH Zurich, Switzerland.

What does ecohydrology mean to you?
Ecohydrology seeks to integrate biological agents into the study of the water cycle. For some time I viewed ecohydrology as extension of agronomic concepts to natural vegetated systems, but it is now abundantly clear that natural systems are far more complex than most monocultural agroecosystems with biologically diverse agents (fauna and flora) inhabiting heterogeneous landscapes and responding to random and episodic inputs. These aspects and the wide range of biomes distinguish ecohydrology making it an exciting new scientific discipline (where agronomic resource management principles become a model system, a special case).

What are your undergraduate and graduate degrees in?
BS and MSc in Soil and Water Sciences of the Hebrew University in Israel ; PhD in Soil, Plants and Biometeorology at Utah State University, Postdocs at UC Davis (LAWR) and UC Berkeley (CEE).

How did you arrive at working in/thinking about ecohydrology?
I have always been interested in plant water relations through my “agronomic” upbringing in a farming community in Northern Israel with keen interest in irrigation management. In Utah I became fascinated with the study of water-limited natural systems. In the past decade, we have been studying surface evaporation (focusing on the roles of soil properties) and evapotranspiration partitioning which naturally require better understanding of plants (from root water uptake to leaf and canopy gas exchange).

What do you see as an important emerging area of ecohydrology?
From my perspective, a key challenge is how to describe large ecosystems (catchments and continents) without losing sight of fundamental physical and physiological processes. Doing ecohydrology across scales with systematic integration of physically-sound processes informed by spatially and temporally extensive data – the future is already here…

Do you have a favorite ecohydrology paper? Describe/explain.
The paper by Schlesinger and Jasechko (2014) on global transpiration was very influential for several reasons: (1) it illustrated the limitations of T estimates by LSM and the need to resolve this aspect; (2) it prompted my ongoing interest in the reasons behind the remarkably constant ratio of T/ET=0.7 (why is that?) and (3) the paper also aimed to tone down inflated claims made in an earlier paper about high ratio of T/ET in natural systems (I thought this was a cool way to achieve this while expanding knowledge).

What do you do for fun (apart from ecohydrology)?
I try to regularly run and work in my yard, and generally enjoy traveling to warm places…

MEET A LEAF: KUDZAI FARAI KASEKE

11/11/2019

Dr. Kudzai Farai Kaseke is an Associate Specialist in the Earth Research Institute at the University of California Santa Barbara.

What does ecohydrology mean to you?
Ecohydrology is the study of the interactions between organisms and their hydrological environment.

What are your undergraduate and graduate degrees in?
BSc Honors in Agriculture – Soil Science, University of Zimbabwe (Zimbabwe)
MSc in Conservation Ecology, Stellenbosch University (South Africa)
PhD in Applied Earth Science from Indiana University (Indianapolis)

How did you arrive at working in/thinking about ecohydrology?
I volunteered for an internship in the Central Namib Desert, Gobabeb Research Centre. In this hyper-arid environment, water availability and ecosystem productivity are tightly coupled making it impossible to study one component without thinking of the other. This was my introduction to dryland ecohydrology which was then further reinforced by my graduate studies which focused also on dryland ecohydrology.

What do you see as an important emerging area of ecohydrology?
The application of stable isotopes to ecohydrological studies. Stable isotopes can be powerful tools that can reveal a lot about ecohydrological processes. They have already started changing the way we think about evapotranspiration and groundwater recharge or streamflow, ecohydrological separation. Combining stable isotopes with other traditional approaches to ecohydrology is thus quite an interesting avenue for me. At the same time, one cannot ignore the potential role for big data in not only ecohydrology but other sciences as well.

Do you have a favorite ecohydrology paper? Describe/explain.
Without a doubt, Noy-Meir, Imanuel. "Desert ecosystems: environment and producers." Annual review of ecology and systematics 4.1 (1973): 25-51. This paper got me interested in how ecology is connected to hydrology within drylands. It highlights ecohydrological processes that we are still trying to understand to this day and is an enjoyable read that’s still relevant to this day.

What do you do for fun (apart from ecohydrology)?
I enjoy hiking, going to the beach and a game of tennis once in a while. Although I no longer play rugby, I am still a huge fan and had a great time watching the just ended 2019 World Cup. Although the All Blacks didn’t win, I’m glad the my second favorite, Springboks were crowned the world champions.

MEET A LEAF: PAOLO D'ODORICO

11/4/2019

Dr. Paolo D'Odorico is a Professor in the Department of Environmental Science, Policy, and Management at the University of California, Berkeley.

What does ecohydrology mean to you?
I consider Ecohydrology as the science that studies the role of water in the functioning of terrestrial ecosystems through the analysis of two-way interactions of hydrological processes with the biota. This includes for instance both the biotic controls on the water cycle through processes such as evapotranspiration, precipitation, or infiltration, and the hydrologic controls on the dynamics of plant and microbial communities, biogeochemical cycles, and species dispersal.

What are your undergraduate and graduate degrees in?
I have an undergraduate degree in Civil Engineering and a Ph.D. in Hydraulic Engineering.

How did you arrive at working in/thinking about ecohydrology?
I started working in this field quite early during my postdoc with Ignacio Rodriguez-Iturbe. At that time (1998) the term ‘ecohydrology’ still had to become popular. We started with the study of water-limited ecosystems, the hydrologic controls on plant water stress, and the nitrogen and carbon cycles. In the following years I become increasingly interested in lab and field work to investigate the role of soil moisture, vegetation, and fire in the control of soil biogeochemistry, wind erosion, and land-atmosphere interactions. We explored patterns of soil water, nutrient and root distribution in southern African savannas. Field work stimulated new questions on the role of ecohydrological feedbacks in the emergence of bifurcations, alternative stable states, and critical transitions in ecosystem dynamics. In particular, we looked at the role of environmental noise, in the form of interannual rainfall variability and investigated the ability of noise to create order (i.e., spatiotemporal patterns) in ecosystem dynamics.

While I remain interested in dryland ecohydrology I have broadened my interest to subhumid environments, wetlands, and agroecosystems. In recent years I have included humans “in the picture” and investigated socio-environmental dynamics of human appropriation and use of freshwater resources, looking at the ecohydrological limits to the sustainable use of water.

What do you see as an important emerging area of ecohydrology?
Ecohydrology plays a central role in the study the biosphere’s response to climate change, the dynamics of carbon sequestration, and the associated feedbacks on climate. There is an increasing need for improved understanding of how changes in precipitation (i.e., in mean, intermittency and interannual variability) can affect plant community dynamics and species distribution. New tools help us understand the hydrologic controls on patterns of biodiversity and soil carbon sequestration. Independently of climate change, the study of ecohydrological patterns and how hydrological processes and landforms shape ecological communities and their resilience remain an important area for fundamental research in ecohydrology.

Personally, I am fascinated by how water availability is determining the distribution of economic activities (e.g., crop production, livestock grazing, mining) that shape the global patterns of land use and land use change. I am interested in the ecohydrological drivers and impacts of land use and water sustainability.

Do you have a favorite ecohydrology paper? Describe/explain.
My absolute favorite is Rodriguez-Iturbe, et al. (1999; Probabilistic modelling of water balance at a point: The role of climate, soil and vegetation, Proc. R. Soc. London, Ser. A, 455, 3789–3805). This paper provides a process-based, comprehensive description of soil moisture dynamics accounting for the role of rainfall regime, soil properties, and vegetation, based on a stochastic representation of the soil water balance. This framework contributed to shape the field of ecohydrology. It has been used to study the role of soil moisture in biogeochemical cycles, vegetation dynamics, plant water stress, pattern formation, land-atmosphere interactions, and many other research questions in ecohydrology.

On the more ecological side, I have been inspired by the work by Walker et al. (1981; Journal of Ecology 69: 473–498) on the stability of grazing systems. This paper has been the precursor of more recent research on stability and resilience in ecohydrology, though back then, nobody was referring to this field as “ecohydrology”.

What do you do for fun (apart from ecohydrology)?
I like to travel to new places, both domestically and internationally. In my everyday life I like to repair antique frames.

MEET A LEAF: Giulia Vico

10/28/2019

Dr. Giulia Vico is an Associate Professor (Docent) in the Department of of Crop Production Ecology
at the Swedish University of Agricultural Sciences.

What does ecohydrology mean to you?
Ecohydrology to me is the study of the interactions between the hydrologic cycle and life - vegetation in my research - and how such interactions are altered by and are affecting human societies.

What are your undergraduate and graduate degrees in?
I hold a Master (a 5-year ‘Laurea’) in environmental engineering from Polytechnic of Turin and a PhD in civil and environmental engineering from Duke University.

How did you arrive at working in/thinking about ecohydrology?
As an engineer and hydrologist, life was not a big part of the picture during my bachelor and masters degrees. But as a person enjoying to be out in nature, life - and plants in particular - were key. That led me naturally to being curious about the interactions between plants and hydrology.

I met ecohydrology almost by chance during my master thesis, thanks to Amilcare Porporato. I soon discovered there were many bidirectional interactions between vegetation and hydrology, and that they were shaped by the variability and unpredictability of rainfall. I was soon fascinated by the use of mathematics to explore the interactions between water and plants, using dynamical systems and stochastic processes to capture the linkages between hydrology and plant ecophysiology and, more in general, physics and biology. And I never looked back! Over the years I have transitioned from natural ecosystems to managed ecosystems, where the human dimension plays a crucial role.

What do you see as an important emerging area of ecohydrology?
There are many exciting areas in ecohydrology. Personally I think ecohydrology is moving more and more towards studying plant-water interactions in managed ecosystems and how these interactions are shaped and shape societies and their decisions. These dimensions have clear practical implications, when we are faced with more extreme climatic conditions and the need to support an ever increasing population, with limited resources in terms of water but also land. These dimensions are also fascinating as they hinge on decision making under uncertainty, an aspect that is seldom explored in strictly STEM curricula.

Do you have a favorite ecohydrology paper? Describe/explain.
Many papers in ecohydrology inspired and continue to inspire me. But the paper that got me started in ecohydrology, when I was still a master student, is Laio et al 2001 “Plants in water-controlled ecosystems: active role in hydrologic processes and response to water stress: II. Probabilistic soil moisture dynamics” - part of a four-paper series that appeared in Advances in Water Resources. There, plant-water interactions are conceptualized via a stochastic differential equation, simple enough to be elegantly solved analytically.

What do you do for fun (apart from ecohydrology)?
I like to be active outdoors. Hiking up and down the mountains in a sunny day is the best. But it is also pleasant to bike in the countryside, swim in the lakes and sea, run and go skiing.

MEET A LEAF: MITCH PAVAO-ZUCKERMAN

10/21/2019

Dr. Mitch Pavao-Zuckerman is an Assistant Professor in the Department of Environmental Science and Technology at the University of Maryland, College Park.

What does ecohydrology mean to you?
Ecohydrology is reciprocal – it captures how hydrology structures and drives ecological pattern and process, but also how organisms and their interactions influence hydrologic dynamics.

What are your undergraduate and graduate degrees in?
I have a B.A. in Environmental Studies from Binghamton University, an M.S. in Plant and Soil Sciences from University of Tennessee, and a Ph.D. in Ecology from the Oduym School of Ecology at the University of Georgia.

How did you arrive at working in/thinking about ecohydrology?
Although I was working in urban riparian ecosystems and soil ecology for my PhD research, I didn’t really start thinking about or working in ecohydrology in a formal way until I moved to Tucson, AZ and started working with Travis Huxman. It was eye-opening moving from a more biogeochemical group to one that focused on physiological ecology. We would spend a lot of time waiting for rain, chasing storms, and adding our own water pulses to desert ecosystems. As an ecologist, deserts drive home the importance of water for everything we think about as ecologists – community structure, spatial distributions, species interactions, ecosystem processes. Thinking about those pulses in cities and connecting with a practitioner of urban permaculture started me working on green infrastructure as a way to reconnect ecohydrologic flows and processes in cities. Simple shifts in how and where water moves by manipulating soil, plants, and concrete has big impacts for ecology, ecosystem services, and people in desert cities. I’ve brought that urban ecohydrology focus with me to the mid-Atlantic where we’re exploring how green infrastructure influences ecohydrological fluxes and how that impacts water flows and water quality.

What do you see as an important emerging area of ecohydrology?
So many of us seem to be drawn to understanding urban ecohydrology, but I think within that an important emerging area really gets down to understanding the role of people in ecohydrology. Be it socio-ecohydrology, socio-hydrology, whatever we want to call it, figuring out reciprocal influences between the two is going to be key to transitioning to more sustainable and resilient water systems. The frontier is really in the human side of that, getting past metrics, indices, and accounting to understanding how decisions get made – what information is (and isn’t) used, how worldviews are shaped, how institutions function as things, but also as collections of people. This really is going to require partnerships and collaboration – stepping out of how we much approach a problem from our (already interdisciplinary) ecohydrology view and listen to those who come from other ways of seeing these urban systems. This includes both people who study how decisions are made (by people, by organizations) but perhaps more importantly, working in partnership with the people and groups making decisions that affect ecohydrology.

Do you have a favorite ecohydrology paper? Describe/explain.
Picking a favorite is always hard! There were a lot of classic desert soil ecology papers from people like Diana Wall (like, Wall, D. H., and R. A. Virginia. 1999. Controls on soil biodiversity: insights from extreme environments. Appl. Soil Ecol, 13:127-150) and Walt Whitford (Whitford WG (1989) Abiotic controls on the functional structure of soil food webs. Biology and Fertility of Soils 8:1-6) that really drove home the connections between patterns of water availability and the dynamics of soil food webs- that’s really where I got my start in ecohydrology. Tardigrades get a lot press, but anhydrobiosis in nematodes is where it’s at! More recently as I think about water in the context of decision making and urban social-ecological systems, I really like this paper by Claudia Pahl-Wostl (Pahl-Wostl, Claudia. 2007. Transitions towards adaptive management of water facing climate and global change. Journal Water Resources Management 21(1): 49-62.). This paper was one of the first I encountered that got me thinking deeply about the role of people in managing water within that coupled social-ecological context. It was grounded in familiar territories of complex adaptive systems and adaptive management, but introduced me to new ways of thinking about social learning and system transformation.

What do you do for fun (apart from ecohydrology)?
I love to spend time with my family – getting to explore the area we’ve recently moved to brings lots of new places to visit, be it stomping in the neighborhood stream to finding hidden treasures at the Smithsonian downtown. Music is also so much fun – finding new things to listen to, seeing live music, or even getting a rare chance to lend my tenor voice to a local ensemble, all great ways for me to relax and have fun.

MEET A LEAF: RUSS SCOTT

10/14/2019

Dr. Russell Scott is a Research Hydrologist at the United States Department of Agriculture (USDA) Agricultural Research Service (ARS) Southwest Watershed Research Center in Tucson, Arizona.

What does ecohydrology mean to you?
The study of the interactions between plants and the water cycle.

What are your undergraduate and graduate degrees in?
University of Arizona    Hydrology and Water Resources         Ph.D.
Massachusetts Institute of Technology            Civil and Environmental Eng./Hydrology M.S.
Colorado State University        Mathematics/Philosophy          B.S.

How did you arrive at working in/thinking about ecohydrology?
My educational lineage began with Dara Entekhabi (MIT) and Randy Koster (NASA), who were direct disciples of the Grand Master of theoretical ecohydrology, Peter Eagleson (MIT). I learned from them about the interactions between hydrology and the climate. We looked at how different mathematical descriptions of the land surface in climate models affected land surface and climate memory. More “realistic” models that explicitly accounted for precipitation interception, i.e. by plant canopies, and its subsequent “fast” evaporation back to the atmosphere imparted less memory to the climate than traditional bucket models.

I moved to Arizona to work on more regional problems and learn how to collect data from the field from a wonderful mentor, David Goodrich (USDA-ARS). I was also fortunate enough to run into another Master, Jim Shuttleworth, who took me under his wing at the University of Arizona. I learned micrometeorology from him and started making my own measurements of land surface fluxes, ultimately shedding light on how riparian ecosystem water use, photosynthesis and respiration were influenced by how well the plants were tapped into groundwater.

A big technological development came along when I was a graduate student: low-power, fast-response gas analyzers coupled with low-power dataloggers that can store the data. Thank you Campbell Scientific and LiCor! This meant we could start making measurements where we don’t have line power and having gas analyzers that could measure both carbon dioxide and water vapor. The later meant I had to learn something about carbon dioxide fluxes, further cementing my ecohydrological interests.

What do you see as an important emerging area of ecohydrology?
We are seeing new ways to partition measured evapotranspiration into its evaporation and transpiration sources. Combining this with the ton of available eddy covariance water and carbon fluxes like that from AmeriFlux allow us a whole new look into ecosystem-scale plant-water interactions, being able to see what the plants are doing separately.

Do you have a favorite ecohydrology paper? Describe/explain.
Noy-Meir, Imanuel. "Desert ecosystems: environment and producers." Annual review of ecology and systematics 4.1 (1973): 25-51.

The water limitation in desert environments really brings out the linkages between ecosystems and their hydrology. This paper highlights so many ecohydrological processes that we are still working to understand today. The great thing is that we now have the data to do that.

Huxman, Travis E., Keirith A. Snyder, David Tissue, A. Joshua Leffler, Kiona Ogle, William T. Pockman, Darren R. Sandquist, Daniel L. Potts, and Susan Schwinning. "Precipitation pulses and carbon fluxes in semiarid and arid ecosystems." Oecologia 141, no. 2 (2004): 254-268.

I have to laugh as I remember the first time I saw this work on a poster I thought to myself, “Is that all?” This is not the first time, my first impressions about a paper were wrong. Fifteen years later, I’ve probably cited this paper more than a hundred times. It does such a great job of synthesizing the literature on ecosystem metabolic responses to intermittent pulses of water, and it lays out some many new hypotheses that we’ve been trying to test ever since.

What do you do for fun (apart from ecohydrology)?
I love rambling around outside whether that is on foot, wheels or skis. If there are mountains and a friend or two around, then I’m even happier.

MEET A LEAF: RACHEL GABOR

10/7/2019

Dr. Rachel Gabor is an Assistant Professor in the School of Environment and Natural Resources at The Ohio State University. @RiverChem

What does ecohydrology mean to you?
I like to think of water as the driving force behind how everything works in the natural world. Water shapes the landscape, determines habitats, acts as a solvent, transports particles and solutes, and is present in every living thing. Ecohydrology is focusing in on that relationship between water and life – how the presence, absence, and movement of water drives life, and how life uses and moves water.

What are your undergraduate and graduate degrees in?
I have a B.S. in Chemistry from Harvey Mudd College, an M.S. in Chemistry from the University of Minnesota, and an M.S. in Water Resources Engineering and Ph.D. in Environmental Studies from University of Colorado Boulder.

How did you arrive at working in/thinking about ecohydrology?
My undergrad degree was in chemistry, with a lot of math and physics, but I kept wavering on my major because I wanted to study everything. Near the end of college I learned about the existence of biogeochemistry and thought it was cool that there was this field that let you combine a bunch of different sciences, but assumed I’d missed my chance to major in it (my college had no classes in the earth/environmental sciences).

After my M.S. I joined an AmeriCorps program and spent several months in Louisiana and Mississippi doing Hurricane Katrina recovery work. It opened my eyes to how engineering decisions we make about our landscape and, more specifically, waterways, can end up having severe consequences for both ecosystems and people. I learned a lot that year and when it ended I decided to go find if there was some way I could use my science background to study water, the environment, and human-environment interactions. Turns out there was this entire field of science that did just that! As soon as I started taking classes in graduate school I realized that the hydrologic sciences was a perfect fit for me – I loved that I could use everything I learned in chemistry and math and physics and biology and integrate them into trying to understand how watersheds work. Lately I’ve been moving away from more natural systems and focusing my research on human-impacted systems, trying to get back to the human-environmental interactions that initially inspired me to go this route.

What do you see as an important emerging area of ecohydrology?
Urban systems. I think historically a lot of hydrology research focused on understanding everything possible in whatever cool “natural” catchment was nearby, and we learned a ton from that. But just in the 10 years I’ve been in this field I’ve seen more and more research focused on understanding urban systems. Urban ecohydrology takes all the complications of hydrology in a natural system and adds human engineering/infrastructure on top of it. Understanding it is a fantastically complicated interdisciplinary puzzle and one where you can really see the potential for your research to help people.

Do you have a favorite ecohydrology paper? Describe/explain.
I chose to get my PhD from an interdisciplinary environmental studies department in the hope that it would help me learn how my science could fit into larger society and decision-making. I went into my second semester loving everything I was learning but frustrated at what felt like a complete rift between science and policy. Then I read Kate Brauman’s The Nature and Value of Ecosystem Services: An Overview Highlighting Hydrologic Services and it completely opened up this whole new perspective for me. It was my first exposure to the idea of ecosystem services, and framed them through the lens of hydrology. I loved that there was a way to take all the things I valued as a scientist and someone who loved the natural world, and couch them in policy language.

What do you do for fun (apart from ecohydrology)?
I’m still working on finding that elusive early tenure-track work/life balance. I learned to play ice hockey in graduate school and still try to get on the ice when I can. I crochet (afghans, hats, scarves), usually while watching some science fiction tv show, and take my dog on regular walks/runs. I used to play board/card games frequently but have been having trouble finding people to play with since I moved to Ohio.

MEET A LEAF: KIM QUESNEL

9/30/2019

Dr. Kim Quesnel is a Postdoctoral Research Scholar at Stanford University with the Woods Institute for the Environment and the Bill Lane Center for the American West. @kimquesnel

What does ecohydrology mean to you?
Ecohydrology is the intersection between hydrology and ecology, and traditionally ecology has referred to the natural environment. However, given the undeniable and ever-present interconnections between people and our surroundings, I think it is important that we also include human ecosystems when we study water.

What are your undergraduate and graduate degrees in?
I have an undergraduate degree in Civil Engineering from Cal Poly, San Luis Obispo, and graduate degrees in Civil and Environmental Engineering from Stanford University, with a Master’s concentration in Environmental Fluid Mechanics and Hydrology and PhD concentration in Environmental Engineering and Science.

How did you arrive at working in/thinking about ecohydrology?
My journey into the water world started as an undergraduate through two avenues. First, I was involved with Cal Poly’s Engineers Without Borders group, designing and planning the implementation of slow sand filters for water treatment in a remote Thai village. Over the course of the three years I was involved with the program, including a site visit, it became clear to me how central water is to every single aspect of life. Second, I participated in a summer NSF REU program at the O.H. Hinsdale Wave Research Laboratory at Oregon State University studying tsunami waves, which opened my eyes not only to water science and engineering, but also to research itself as I was coming from a primarily undergraduate teaching university. I then worked in environmental consulting for a few years before returning to graduate school, at which point I thought that I wanted to study fluid mechanics based on my positive experience at the wave lab.

However, I soon realized that I wanted to work on systems-level and policy-relevant water challenges. This realization was partially motivated by the fact that it was early on in the 2012–2016 historic California drought, which highlighted the inefficiencies and shortfalls of our current water management strategies. My interests snowballed from there to where I am today, and I would classify my research as urban socio-ecohydrology.

What do you see as an important emerging area of ecohydrology?
One emerging area that I see for all fields of hydrology is the proliferation of big data. Not only are we seeing higher frequency measurement devices or improved computing power and data storage capabilities, but also the emergence of new data sources themselves. One example is that can now develop proxies for previously difficult to quantify variables. In sociohydrology, for instance, we can use internet search frequency or news media articles to understand public awareness or interest in a meteorological event instead of relying on surveys.

Do you have a favorite ecohydrology paper? Describe/explain.
My favorite recent socio-ecohydrology paper is Breyer, Zipper, and Qui, 2018 which was published in Water Resources Research. The authors incorporated a suite of modeling techniques and data sources to paint a holistic picture of human–water interactions during drought. By combining physical attributes like streamflow and climate data with remote sensing and sociodemographic data, they were able to geospatially-explicitly demonstrate how drought can impact human water use behavior, which then feedbacks and impacts water resources. I actually thought that this paper was so elegant that I emailed the authors (who I have never met) to let them know—which is a practice that I want to continue in the future. I think it is important we create a culture of positivity in our field and let our peers know when we are excited and impressed by their work!

Two other recent papers that I like are Mini, Hogue, and Pincetl, 2014 and 2015 on urban water use in Los Angeles. Although these papers are only five years old, I feel like they were very progressive in combining big water use datasets with remote sensing data to estimate outdoor water use and the impact of restrictions.

What do you do for fun (apart from ecohydrology)?
Like many hydrologists, I love being outside! My favorite activities are mountain biking and skiing, but I also love running and hiking. A few weeks ago, I went on a backpacking trip with my mom in the Eastern Sierra Nevada mountains in California which was really special—we retraced the route that she was in charge of 40 years ago when she was a backcountry forest ranger in early her early 20s.

MEET A LEAF: RYAN EMMAnUEL

9/23/2019

Dr. Ryan Emanuel is an Associate Professor and University Faculty Scholar at North Carolina State University. @WaterPotential

What does ecohydrology mean to you?
In a general sense, I consider ecohydrology the study of bi-directional interactions between hydrological and ecological processes. Much of ecohydrology could be organized under high-level questions like: how do water status and flow influence ecosystem structure and function, and how do ecosystem structure and function affect water status and flow? The boundaries of ecohydrology are fluid (no pun intended) and ever-expanding, which is something I welcome.

What are your undergraduate and graduate degrees in?
I have a BS in Geology from Duke University and graduate degrees in Environmental Sciences from the University of Virginia.

How did you arrive at working in/thinking about ecohydrology?
I was exposed to one particular vein of ecohydrology early in graduate school. Paolo D’Odorico, my MS committee member and eventual PhD co-advisor, worked with Ignacio Rodriguez-Iturbe on interactions between soil moisture and vegetation in one-dimensional water balances. Their conceptual framework strongly influenced my early research. I paired some of their concepts with flux tower methods taught by other mentors, John Albertson and Howie Epstein, to study impacts of plant water stress on ecosystem carbon and water cycles.

Later on, my PhD co-advisors, D’Odorico and Epstein helped me extend ideas about water stress to questions about streamflow, evapotranspiration, and biogeochemical cycling across entire watersheds. At this scale, water is still a vital resource for ecosystem functions, but it also carries information about finer-scale ecohydrological processes from one part of the landscape to another. As an early-career scientist, collaborations with watershed hydrologists like Brian McGlynn, Lucy Marshall, and their students helped me think about ecohydrological processes as part of amazingly complex catchment systems. For the past decade or so, my students and postdocs have taken this basic view of ecohydrology and enriched it with their own creativity and insight.

What do you see as an important emerging area of ecohydrology?
Although I feel like I work in one small corner of ecohydrology, I can see important conceptual advances on the threshold, if not already coming through the doorway of our discipline. Conceptually, ecohydrology still has a lot to learn about water’s dual role as a limiting ecological resource and as a carrier of signals across landscapes. Because we don’t have universal definitions for phenomena like water stress or for what it means for water to “carry a signal,” there are emerging opportunities to draw connections between great work happening now throughout the ecohydrology community.

I think that many in our community recognize the fluidity of ecohydrology’s scope and boundaries. For that reason, I think it’s important to acknowledge that an emerging area of ecohydrology is its ability to look outward and connect with other fields, while still carrying out robust research at the core of our field. For my part, I’ve begun connecting ecohydrology with broader societal questions about public policy, environmental justice, and indigenous knowledge systems. I am a citizen of the Lumbee Tribe, a group that is indigenous to the southeastern part of the present-day US state of North Carolina. Our territory encompasses blackwater streams and forested wetlands that provide great examples of bi-directional interactions between hydrological and ecological processes. However, when I look at these landscapes as Lumbee person I also see deep historical and cultural relationships between people, land, and water that help define us as indigenous people. My training in ecohydrology gave me one particular set of tools for thinking about relationships between land and water, and I consider those tools incomplete. Lumbee people, like many indigenous peoples, I have much richer ways of understanding relationships with land and water.

I think indigenous ways of knowing are important to share with others, because they help us see the bigger picture of water and life. Indigenous perspectives can be important to consider when we are building socio-hydrological models, developing public policies, planning fossil fuel pipelines, or engaging in a host of other activities that affect relationships between ecosystems, water, and people. In recent years, ecohydrology has been grappling with ways to incorporate human dimensions into modeling and quantitative analysis. This is important work that can benefit from indigenous perspectives.

Do you have a favorite ecohydrology paper? Describe/explain.
I don’t have a favorite ecohydrology paper, although many papers have influenced my thinking about ecohydrology through the years. When I think about representation of indigenous perspectives in ecohydrology (or other fields), one influential paper is “A global assessment of Indigenous community engagement in climate research” by Dominique David-Chavez and Michael Gavin, published last year in Environmental Research Letters. Focusing on published climate studies, they find most published research to be extractive rather than participatory or community-based. The paper is a call to respectful, conscientious, and responsible research partnerships with indigenous peoples.

What do you do for fun (apart from ecohydrology)?
I have a lifelong love of paddlesports that has evolved through various stages of my life. I am currently into canoeing and paddle boarding on blackwater streams in eastern North Carolina, sometimes alone and sometimes with family or friends. As a Lumbee person, I descend from Indigenous peoples who have paddled canoes on these exact streams since time immemorial. Also, one of my postdocs taught me to brew kombucha earlier this year. I enjoy sharing kombucha with family and friends.

MEET A LEAF: EDOARDO DALY

9/16/2019

Dr. Edoardo Daly is an Associate Professor in the Department of Civil Engineering at Monash University, Melbourne, Australia.

What does ecohydrology mean to you?
Sometimes, I feel like ecohydrology could really be anything, because it encompasses water and ecosystems, and, as such, many studies could fall under the label of ‘ecohydrology’. This explains to me why ecohydrology spans across so many different disciplines. If I had to pick a definition of ecohydrology, however, I am fond of the first one that I read as a young student, which is given by Rodriguez-Iturbe in his WRR commentary in 2000: “Ecohydrology may be defined as the science which seeks to describe the hydrologic mechanisms that underlie ecologic patterns and processes.”

What are your undergraduate and graduate degrees in?
I studied in Italy when the university degrees were designed to be 5-year long (even though it took often longer than that to finish) and students were awarded a ‘laurea’, which is equivalent to a master’s degree. I have a ‘laurea’ in Mechanical Engineering and a PhD in Hydraulic Engineering, both from the Politecnico di Torino.

How did you arrive at working in/thinking about ecohydrology?
Having studied mechanical engineering, I did not know what hydrology was before starting my PhD. I did the thesis for my master’s degree in the department of civil engineering looking experimentally at near-wall turbulence in open channels. The decision to start a PhD came when the supervisors of my master’s thesis, Luca Ridolfi and Amilcare Porporato, offered me the opportunity to go to Princeton University and be supervised by Ignacio Rodriguez-Iturbe for one year. I like mathematics, and became absorbed by the theory of stochastic processes, which finds applications in rainfall and soil moisture dynamics modelling. So, my introduction to ecohydrology was really through stochastic processes and the elegant analytical solutions of some of the models used to describe soil moisture dynamics. During my post-doc I had some experience in the field, and after moving to Australia I started working more in the field. I now appreciate the complexity and difficulty of building up good and long dataset and look at the diversity of ecosystems not just in terms of different parameters. I found a balance between experimental and theoretical work, even though I still prefer the modelling side of things.

What do you see as an important emerging area of ecohydrology?
I think urban ecohydrology will keep us busy for a long time. The built environment adds a lot of complexity to ecosystems, generating interaction and feedback loops that need to be explored and likely discovered. There is space for studies at different scales, from individual street trees to large parks and natural reserves, these last ones rather common in Australian cities. The opportunity to design parts of urban ecosystems, for example by engineering natural areas for rainwater or stormwater harvesting, is also very intriguing. It is quite interesting to see people with very different backgrounds, such as ecologists, hydrologists, climatologists, architects and engineers, work together on problems related to urbanization and urban developments.

Do you have a favorite ecohydrology paper? Describe/explain.
I do not really have a single favorite paper, but I am attached to Rodriguez-Iturbe et al. (1999) "Probabilistic modeling of water balance at a point: The role of climate, soil and vegetation" and then the series of four papers by the same group in Advances in Water Resources. These papers represented my introduction to ecohydrology via stochastic processes, and they have been my ‘daily bread’ during my PhD.

What do you do for fun (apart from ecohydrology)?
I like spending my free time with Tiffani, my wife…whether it is going for walks, watch movies, cook, or whatever, it is always fun.