Kingsley Nnaemeka Ogbu is a lecturer at the Department of Agricultural and Bioresources Engineering, Nnamdi Azikiwe University, Nigeria. Currently, I am a researcher at the Center for Development Research (ZEF), University of Bonn, Germany.

What does ecohydrology mean to you?
I understand ecohydrology to mean an interdisciplinary research area concerned with the interactions between ecological processes and the hydrologic system. Understanding these interactions/feedbacks under uncertain climate and human population growth is key to achieving sustainable watershed management and water resources development.
 
What are your undergraduate and graduate degrees in?
I obtained a Bachelor of Engineering in Agricultural and Bioresources Engineering in 2007 from the University of Nigeria. My master's degree is in Soil and Water Resources Engineering from the same university.

How did you arrive at working in/thinking about ecohydrology?
During my master´s degree program, I joined my professor´s research group - the Eco-hydrology and System Research Unit (EHSRU). He was a Professor of Eco-Hydrology had developed an eco-hydrologic model in his doctoral study in Canada. From that moment, my research interests developed and grew to my current level now.  My first research experience was working with the Soil and Water Assessment Tool (SWAT) to understand the impact of land use/cover changes on hydrologic processes. The critical role evapotranspiration plays in the hydrologic system should never be downplayed during eco-hydrologic model development.

What do you see as an important emerging area of ecohydrology?
An important emerging area of ecohydrology is socio-ecohydrology. It is the study of interactions and feedbacks between humans, ecology, and water systems. Human activities have significantly reshaped the natural landscape with impacts on ecological and hydrologic systems. Anthropogenic activities have also affected our climate system and increased uncertainties in weather projections. Research which contributes to understanding the feedbacks between human, ecological and water systems will be a great contribution towards achieving sustainable watershed resources management.

Do you have a favorite ecohydrology paper?  Describe/explain.
Krysanova, V and J. G. Arnold (2008) Advances in ecohydrological modelling with SWAT—a review, Hydrological Sciences Journal, 53:5, 939-947.
This review provided me with information on the development of the SWAT model as an ecohydrological model. I will say that this is the first ecohydrology research paper that I read and which also introduced me to other relevant related literature.  

What do you do for fun (apart from ecohydrology)?
I am also a sportsman and particularly like track and field events.    

Dr. ​Constantine C. Mbajiorgu is a Professor of Ecohydrology and Soil and Water Engineering
in the Department of Agricultural and Bioresources Engineering at the University of Nigeria, Nsukka, Enugu State, Nigeria.

Dr. Dennis Baldocchi is a Professor in the Department of Environmental Science, Policy, & Management at University of California Berkeley.

One aspect of our research is on the coupled water and carbon fluxes of oak savanna and annual grasslands in the Mediterranean climate of California.  We are interested in how whole ecosystems response to seasonal and interannual variations in rainfall. California is the perfect natural laboratory because our wet season is followed by a long dry period, so we can track the draw down in soil moisture and how it affects these gas fluxes.  California also experiences high year to year variability in rain fall (+/- 30%) so we also get to see the effects of busts and booms in rainfall on ecosystem structure and function.  This enables us to explore the broad non-linear response that is difficult to mimic with rain addition and exclusion studies.  This long term and field scale work also gives us the chance to see surprises, like how evaporation is tied to ground water and how ground water is tied to the snowpack of the Sierra Nevada mountains, nearly 100 km away.

The second aspect of our research is on flooded ecosystems (rice and wetlands). We are interested in how these ecosystems produce methane and store carbon in anoxic sediments.  We are also discovering surprises about the complex role of detritus and water temperature on evaporation and the role of plant exudates on methane production.

What are your undergraduate and graduate degrees in?

• BS in Atmospheric Science from University of California, Davis
• MS in Agricultural Engineering from University of Nebraska, Lincoln
• PhD in BioEnvironmental Engineering from University of Nebraska, Lincoln, with focus on Agricultural Meteorology 

How did you arrive at working in/thinking about ecohydrology?
I have a long interest in evaporation of plant canopies, starting with irrigating walnuts as a kid and taking Bill Pruitt’s evaporation course at Davis.  My thinking became formalized in grad school.  We studied evaporation and carbon exchange of soybeans and alfalfa with flux gradient methods.  I wanted to know how and why the fluxes varied with hot, dry conditions.  So, from the get-go we were measuring stomatal conductance and pre-dawn water potential.  Hence, my focus on the ecophysiological control on ecosystem water exchange (as shown in the figure above). This mind set continued as I started to study evaporative fluxes of native forests in Tennessee and Canada.  There, my ability to do ecohydrology was stymied because a drought would start and then it would rain, so I never got a wide enough range of conditions to satisfy myself.  This changed when I moved back home to California and set up the savanna field sites. 

My formal exposure to the field of ecohydrology came by reading the papers and books of Ignacio Rodriguez-Iturbe and collaborators.

What do you see as an important emerging area of ecohydrology?
Our mantra is to be able to assess evaporative fluxes ‘everywhere, all the time’.  Now this requires understanding down regulation of evaporation with soil moisture deficits and upscaling evaporation with remote sensing.  At present, satellite remote sensing is unable to peer deep enough into the soils.  We are interested in the role of using plants as soil moisture sensors and using information they telecommunicate to the state of the boundary layer as a transmitter of that information.  How well this works across the globe in different climates remains an open question.

We are also on the verge, with flux datasets reaching 20 years, on assessing whether and or how much ecosystem evaporation is responding to a warmer world with more CO2.  There have been lots of inferential estimates but we need more direct measurements. And, here too, the answer may be conditional with time and location.

Do you have a favorite ecohydrology paper?  Describe/explain.
Jarvis, P.G. and McNaughton, K.G., 1986. Stomatal Control of Transpiration - Scaling up from Leaf to Region. Advances in Ecological Research, 15: 1-49.
The paper resolves the conflict between ecophysiologists, who argue that warming may increase evaporation by forcing a greater vapor pressure at the leaf surface, with meteorologists, who argue that warming may reduce evaporation due to more longwave energy and sensible heat loss.  It also ties together ideas on how, when and where evaporation is better coupled with available energy and/or canopy surface conductance and humidity deficits. It provides the paradigms on which I base the interpretation of much of my research in the past and today.

What do you do for fun (apart from ecohydrology)?
Until I was 52, I played pick-up soccer regularly.

Lately I have started throwing Master’s Level discus (1 kg).  There is a group of us, age 65 to 80, who meet each Saturday in a cow field near Petaluma, CA and throw discus on a ring a friend built (Chileno Valley Discus Club).  It is getting me back in shape and has helped me endure Covid.   The only problem is I am not throwing as far as I did in high school.  I am working hard to reach 30 m.
In addition, I continue to do day hikes, love listening to jazz and baking sour dough bread.

Dr. Miriam Coenders is an Assistant Professor at the Water Resources Section of Delft University of Technology, The Netherlands. ​@miriamcoenders 

What does ecohydrology mean to you?
As a water engineer, I am trained to shape the world: design irrigation systems, decide upon pumping capacities for draining the land, or (re)design polder systems. However, the world where these interventions take place is not static. Under climate and land use change, water always finds new pathways, where vegetation plays a major role. Vegetation controls how much and where water enters the soil, it consumes water for plant growth affecting our climate, and provides friction for water flow. Hence vegetation is key in our hydrological cycle and cannot be seen separately, as such the term ecohydrology is a sort of pleonasm. I realize that ecohydrology is much broader than I define here, but for me it is the role of vegetation in our water world.
 
What are your undergraduate and graduate degrees in?
I have a BSc and MSc degree in Civil Engineering from Delft University of Technology, where I specialized as hydrologist. After my Masters I did my PhD-study on the role interception in the hydrological cycle at research institute LIST in Luxembourg with TU Delft as awarding university.
 
How did you arrive at working in/thinking about ecohydrology?
In the Netherlands, we are raised with the high awareness for flooding. Maybe due to this, we falsely tend to think that all precipitation ends up in the river. So, during my studies, I was really astonished by the power of evaporation and the limited knowledge on this important hydrological process. Therefore, I decided to focus my research around the topic of evaporation. Once we better know how evaporation behaves, we can really improve water resources management including flood and drought predictions. Additionally, the cool thing about evaporation is that links the land with the atmosphere in such way that eventually also our weather forecasts can be improved. So, for the future I dream about no more drowned field work activities!
 
What do you see as an important emerging area of ecohydrology?
I think in the past many researchers in the field of ecohydrology tried to study plants and soils at the small scale. From these studies we learned a lot about the water behavior of plants; however, these laws often limitedly work on the larger scale. On the other hand, remotely sensed information is able to capture the larger scale, but is difficult to downscale. Therefore, observation techniques that are somehow in between these two scales would help us to understand how small-scale processes evolve into large-scale behavior. Luckily, more and more new observation techniques arise (e.g., stable water isotopes, thermal infrared imagery, distributed temperature sensing, drone technology) and also the sensor development itself becomes easier, which enables researchers to make tailor-made instruments themselves. Especially, the latter facilitates unique insights in the field of ecohydrology.
 
Do you have a favorite ecohydrology paper?  Describe/explain.
One of the papers I really appreciate is the work of Renée Brooks et al (2009) entitled “Ecohydrologic separation of water between trees and streams in a Mediterranean climate”. They introduced a new theory on where trees get their water from and challenged the long-standing assumption that all infiltrated water is affected by evaporation or root water uptake. Whether it is true or not, these new out-of-the box theories help to fresh up our minds and avoid possible tunnel visions. In my view, it is good to -now and then- challenge existing ‘set-in-stone’ theories. Additionally, I very much liked the book “Precipitation partitioning by vegetation” edited by John van Stan, Ethan Gutmann and Jan Friesen (2020). Apart from being a very comprehensive compilation of all the past and possible future partitioning work, it has awesome graphics. It is really fun to read and sets a standard for future textbooks.
 
What do you do for fun (apart from ecohydrology)?
Apart from ecohydrology?!? Ehhh… annoy my cats with a laser pen? Yeah... that’s fun too.

​Dr. Catherine Febria is a Canada Research Chair in Freshwater Restoration Ecology and Assistant Professor in the Dept. of Integrative Biology and the Great Lakes Institute for Environmental Research, University of Windsor, Ontario, Canada which is situated on the Traditional Territory of the Three Fires Confederacy of First Nations. She leads the Healthy Headwaters Lab which focuses on the structure and functioning of small streams, waterways and wetlands in human-impacted landscapes.  ​@ecofebria

What does ecohydrology mean to you?
As a small stream I work at the ‘eco’ side of things, and how the presence, absence and/or intensity of water drives ecosystem functions and biodiversity from molecules up through the food web. I think a lot about how water connects physical and biological processes as well as social dimensions, and how humans influence ecohydrological processes particularly among small and intermittent waterways that are scattered across the landscape.

Also, hydro (water) is at the centre of my work. In many cultures, there is a saying “Water is life” which encompasses my lab’s effort to take a more holistic approach to science. We are all passionate about using science to connect land, water and people, and to advance work that ensures freshwater sustainability for the benefit of future generations.
 
What are your undergraduate and graduate degrees in?
I have an undergraduate degree in Environmental Science from the University of Toronto (Canada) which introduced me to water through a geology and hydrology lens. Later in my undergraduate degree, I took my first field course in marine ecology and realized that I loved looking at the relationship of ecosystem components in aquatic environments. This led me to pursue a Masters degree in Geography from Simon Fraser University in British Columbia (Canada) where my research took me to the dynamic Mackenzie River basin in the western Canadian arctic. I deepened my understanding into how dynamic hydrological systems – from floodplain lakes and rivers to intermittent streams and rivers – were excellent model systems for research on the impacts of climate change. I also realized just how little we actually know about intermittent/temporary streams and rivers in Canada. This led me to a PhD in Ecology at the University of Toronto & Collaborative Certificate in Environmental Studies. For my PhD, I instrumented headwater streams – one intermittent stream and one perennial (permanently-flowing) stream – to explore nutrient and microbial dynamics in the hyporheic zone. The hyporheic zone is the interface between surface and groundwaters, and critical habitat for stream benthic macroinvertebrate and microbial communities. The more I pursued research on this system and at the interface of hydrology and ecological processes, I engaged approaches from different disciplines – from microbiology to chemistry, environmental studies to geography – and also became increasingly aware of the importance of small waterways and the lack of legislative tools to ensure their protection.
 
How did you arrive at working in/thinking about ecohydrology?
I’ve always been called to water conservation and using science to help solve environmental challenges from climate change to food sustainability and species-at-risk. I have long been curious about hydrological processes at varying ecosystem scales, and have enjoyed interrogating these dynamics at a range of spatial and temporal scales. Whether it be arctic river systems, or agriculturally-impacted systems or urbanized ones, I have been drawn to understanding drivers of ecosystem variability and the relationship between hydrological processes, ecosystem functions and biodiversity. It is impossible to restore, conserve or protect water resources without understanding the multifaceted role of water.
 
What do you see as an important emerging area of ecohydrology?
I think that ecohydrology will be increasingly important in exploring the fundamental dynamics of ecosystem processes at the land water interface, in human-impacted landscapes (agricultural, urbanized) and the social dimensions of restoration, food and freshwater sustainability. Ecohydrology is thankfully inherently interdisciplinary so I am excited to contribute to and further connections across disciplines including social and cultural dimensions.

This is one example review: Palmer, M., and A. Ruhi. 2019. Linkages between flow regime, biota, and ecosystem processes: Implications for river restoration. Science 365:eaaw2087.
 
Do you have a favorite ecohydrology paper?  Describe/explain.
It’s hard to pick just one! My PhD supervisor was Dudley Williams, who studied under Noel Hynes and together they pioneered research on the hyporheic zone, connecting ecology and hydrology through explorations of macroinvertebrate communities across this critical transition. I frequently revisit and cite foundational papers in my teaching and research seminars from Tansley’s 1935 essay in Ecology where ecosystem was first defined, and in its’ definition connectivity across scales was acknowledged. One can argue that ecohydrology is well-suited to advance and explore ecological processes across scales.
 
Tansley, A. G. 1935. The Use and Abuse of Vegetational Concepts and Terms. Ecology 16:284–307.
 
For a short read and answers to a common question, I share this paper to help explain how important temporary waters are, and the need for better protection globally. Science has an important role in advancing these efforts.

Acuña, V., T. Datry, J. Marshall, D. Barceló, C. N. Dahm, A. Ginebreda, G. McGregor, S. Sabater, K. Tockner, and M. A. Palmer. 2014. Why Should We Care About Temporary Waterways? Science 343:1080–1081.  

What do you do for fun (apart from ecohydrology)?
Lots! I do a lot of things for fun from traveling, outdoor adventures and exploring nature with my family, to many different forms of art (music, photography, handicrafts, watercolour) and love trying new recipes especially if it involves produce harvested from local farms or our garden plots. I do love a good round of Mahjong (a tile based game from China and played in many Asian cultures) even though I’m not very good at it, I really enjoy the challenge.