California WaterBlog

By Cathryn Lawrence

This blog is the first in a series featuring interviews with scientists from the Center for Watershed Sciences to learn what sparked their passion to pursue a scientific research career. Kicking off the series we interview Jonathan Walter, a Senior Researcher and quantitative ecologist at CWS, who works on issues relating to the stability and resilience of aquatic ecosystems and organisms.

Hi Jon. You have been working remotely for the Center for Watershed Sciences for over two years, but you are now here on campus at UC Davis. Let’s start by introducing you to the California Water Blog audience. Tell us about yourself and your research.

The main threads that tie my research together are an interest in the stability and resilience of natural systems, so questions about their ability to persist in the face of environmental change and to maintain function. And I do that in a range of species, types of natural systems, and organizational scales, sometimes as fine-grained as the physiology of organisms, and other times as zoomed-out as the dynamics of ecosystems over large areas. I’m a quantitative ecologist, so the tools I use are mainly statistical analyses and mathematical models. Oftentimes my research also entails realizing that, hey, there’s a question that we would like to answer, but we don’t have great quantitative tools for it yet, and then working on creating those tools and making them accessible by publishing software.

So you’re not only a tool user, but also a toolmaker. Could you give us some examples of the kind of tools that you’ve worked with?

One of the things that I’ve been interested in studying for a long time is synchronous dynamics in the environment — synchrony referring to a positive correlation in dynamics through time. For example, if you’re thinking about a measurement such as the abundance of a species, the rises and falls in that measurement could be (loosely speaking) simultaneous across multiple places, sometimes over vast areas. That’s something we call spatial synchrony.  

I’ve been quite involved in developing statistical methods that help us better understand patterns of synchrony and infer what mechanisms cause it. One set of tools is made up of extensions of wavelet analysis, which allow us to decompose different timescales or frequencies of variability in time series data. Natural systems feature many timescales of variation with distinct causes — for example, estuaries experience tidal variation, annual cycles associated with the changing of seasons, and the effects of longer-term oscillations in the climate system, like El Niño, that have periods spanning multiple years. The combination of these variations can make it difficult to distinguish patterns and understand their causes. Colleagues and I have developed methods that do a good job accounting for this variation in studies of synchrony, and the software for that is all open source so others can use it.

Can you recall the early experiences that lit your fire for science and nature?

Until I was about nine, I lived on a few acres that backed up to some woods, and I spent a lot of time exploring, finding neat rocks and crystals, frogs and turtles and things like that. Just being in nature. Those experiences impressed on me the value of the natural world and its place as something to be curious about. Although it was much later in my life that I realized, oh, this is something that I might want to study and make a career out of.

When you first got to college, what did you think you were going to study? What did you end up studying?

I initially declared a dual major in English and Philosophy. I love to learn about new ideas and analyze them. Academically, the first place I could do that was in high school English classes, so I gravitated in that direction, but over time my interest waned. But I took a non-majors’ Environmental Studies course to fill a requirement and found myself really drawn in by it, so I changed my major and finished with a B.S. in Environmental Studies.

What was next for you? How was your experience getting your PhD?

I went to a PhD program in Environmental Sciences at the University of Virginia. I worked mainly on insect outbreaks and invasions, which is no longer a big focus of mine, but I learned a lot about being a scientist and some important skills in analyzing large monitoring datasets, and using mathematical models as tools for making predictions and exploring how systems work. Since then, I’ve translated those skills to different problems. Naturally, in the current phase of my career, I’m focused on aquatic ecosystems and the organisms that inhabit them. That’s been really fun for me; there’s an endless supply of interesting and thorny problems with water in California and elsewhere. That work has brought me close to some awesome people, including here at the Watershed Center, and that’s for me one of the things that makes science fun.

That’s great. So what was your PhD in? Ecology or environmental science?

It says Environmental Sciences with a concentration in Ecology. The program is interdisciplinary, spanning ecology, hydrology, atmospheric sciences and geosciences. I think a real strength of that program is that – even though I’m not by any stretch, say, a geomorphologist – I understand a bit of it, and that helps to have a broader perspective on research problems and to be able to interact with the communities who are experts in that area. I think that’s a strength of my background as a scientist, and something I’ve tried to take advantage of, especially now working in this interdisciplinary center, now also adding engineering and law into the mix.

What was your path between your PhD starting your research at the Watershed Center?

Following my PhD, I worked as a postdoc. First at Virginia Commonwealth University, which was largely an extension of my PhD work on insect population dynamics. And then at the University of Kansas, in a very broad quantitative ecology lab. KU was where my research program really started to gain more breadth, and where I grew skills in the development of new methods and software. That was really, really formative for me. After that, some personal forces brought me back to Virginia, where for a handful of years I did research and teaching for a few different universities, as well as a little bit of independent contracting. 

About two and a half years ago, I joined the Watershed Center, at first working remotely. As of early September, I have been out here in person, and it’s been awesome. One thing I’m excited to get out of this move is a better understanding of the ecosystems and human systems of California. Even though I’m rarely involved in collecting new data myself, I think there’s immense value in experiencing systems in person. I’m also really excited about building relationships with people, which is hard when everything is a video call. 

Absolutely delighted to have you sitting here. What are you currently interested in? What directions would you like your research to take?

One thing I’m working on now, with an awesome group of colleagues at UC Davis and elsewhere, is an investigation of space-time patterns in heatwaves in river temperatures, in particular, whether riverine heatwaves co-occur — or in other words, occur synchronously — within local stream and river networks, and regionally across the western US.  Since heatwaves represent extended periods of unusually high temperatures, they can be stressful or even lethal for organisms experiencing them. Understanding whether heatwaves tend to co-occur in many places at once has important implications for maintaining cooler thermal refugia, where mobile organisms can potentially retreat until conditions improve, and which can be sources for recolonizing heatwave-impacted habitats. What we’re finding so far is that riverine heatwaves tend to be partly synchronized at regional and local scales. Regional scales are mediated partly by large-scale climate oscillations like El Niño. At local scales, differences in the degree to which heatwaves co-occur across sites can be mediated by the structure of the river network and by dams, so there are some probable connections to water management. 

One broad direction I’m interested in exploring is how human systems interact with our natural systems, driving change and creating opportunities and constraints on how they transform over time. Something that I think is exciting about that is it necessarily involves collaboration. I don’t pretend any expertise on governance or sociology or economics, but I’m excited at the prospect of pulling these different perspectives together, and I think developing those collaborations will be more feasible now that I’m here in person.

That’s great. So, is there anything else the Water Blog audience should know about you and your research?

I’m interested in a lot of different problems, and I’m interested in helping other people solve their problems. I have my own interests that drive major directions in my research, but an important part of my work also arises from someone coming to me and saying, “I have this dataset, and I have this question, but I don’t really know how to get from a to b.” And then we find a solution. I would be excited to develop this kind of collaboration with other scientists and with practitioners to shed some new light on thorny problems.

Thank you for your time today. We at the Watershed Center are glad to have you boots on the ground here in California!

I’m really happy to be here and look forward to getting to know better my colleagues at the Watershed Center. I’m also looking forward to meeting more scientists, practitioners, and policy makers here in California and getting a better handle on their perspectives and needs. 

Cathryn Lawrence is the Assistant Director at the Center for Watershed Sciences. Jonathan Walter is a Senior Researcher at the Center for Watershed Sciences. 

* This interview has been edited for length and clarity.