Stream Ecosystems in a Changing Environment: an interview with Emily Stanley

An upland stream in the English Lake District. Image: oatsy40 | Flickr Creative Commons

Stream ecosystems form important parts of many landscapes; slim threads of moving water often high in biodiversity (sometimes in the most surprisingly developed places), nutrient and carbon cycling processes and recreational and aesthetic appeal. However, streams across the world are increasingly threatened by pressures including pollution, climate change, abstraction, the spread of invasive species, fragmentation and channel alterations.

A new book ‘Stream Ecosystems in a Changing Environment‘, co-edited by Jeremy B Jones of University of Alaska Fairbanks and Emily H Stanley of the Center for Limnology at the University of Wisconsin provides a timely, cutting-edge perspective on the response of stream ecosystems to environmental change.  We spoke to Professor Stanley to find out more.

Freshwater Blog: Could you tell us a little about ‘Stream Ecosystems in a Changing Environment’, its aims, contents and contributors?

Emily Stanley: The book was inspired by the 2000 book ‘Streams and Ground Waters‘ edited by Jay Jones and Pat Mulholland. Jay and I wanted to provide an up-to-date resource for stream ecologists, and we also very much wanted to honor the memory of Pat Mulholland. Pat was such an influential scientist in the field, but more importantly, a friend, mentor, and truly exceptional and kind human being. We all miss him very much.

As the title indicates, the ‘Streams and Ground Water‘ book had emphasized groundwater and how it affected/interacted with streams and rivers. In this book, we wanted to broaden the scope and consider a range of topics from hydrology, geomorphology, and ecosystem ecology. And in particular, we wanted to bring things into the 21st century and recognize the interactions between humans and the environment. That included presenting new concepts and understanding that have been gained by studying human-dominated streams, and conversely how basic scientific concepts have been used to study these environments.

We wanted the book to be useful for both researchers and managers, and we had learned from the ‘Streams and Ground Waters‘ experience that many of our colleagues found the book to be particularly useful for graduate students. So providing a strong and updated resource for early career scientists was also a major goal.

The contributing authors are a great bunch – and include a mixture of ecological, geomorphological, and hydrological experts. Jay and I invited people to contribute chapters because of their leadership in the field and their creative approaches to their science. Some of these authors come at ecological questions from physical/earth science backgrounds, and bring a perspective that may be new for many stream ecologists. We view this as one of the strengths of the book.

A seasonally dry stream in a forest in Missouri, USA. Image: Kyle Spradley


What are the big themes and challenges in stream ecology?  What are some of the most recent advances in our understandings of stream ecosystems, and where are there still gaps to be addressed?

I think some of the challenges and opportunities that have been unfolding over the past 10-15 years involve understanding streams and rivers at larger spatial scales, learning how to take advantage of new technologies such as automated sensors for measuring water chemistry, and providing information needed to understand and managing streams in rivers in the context of long-term changes in climate, land use, and water use and regulation.

Not surprisingly, there have been lots of major advances in stream and river research over the past decade – often in direct response to these broad challenges. We’ve seen substantial growth in the breadth and capacity of models and statistical methods, more studies of streams and rivers at continental and global scales, new insights from research that takes advantage of the automated sensors as well as from new tools for investigating organic matter composition – as just a few examples.

Overall, we have become far more quantitative in our science. Many of the chapters provide a perspective on the state of the art for new approaches and accompanying insights provided by new tools and models (many of which were developed by the chapter authors themselves). These include, for example: providing a thorough overview of models used to quantify metabolism that make use of data from automated sensors and what new insights we’ve gained from these new approaches, a new quantitative framework for nutrient spiraling that integrates nitrogen and phosphorus cycles, or a detailed consideration of the challenges associated with understanding streams and larger scales – accompanied by the introduction of a new analytical strategy for scaling up results generated from small, reach-scale studies to drainage systems distributed across landscapes.

As these tools/models/frameworks emerge, I suspect that over the next decade we’ll continue to see more tool and model development, but we’ll also see these new strategies put to work. While we’ve made great strides in understanding riverine processes at large scales, I think there are still substantial opportunities in this realm. And clearly much of this work includes the science for dealing with complicated management problems. Gaps and emerging challenges in these areas are particularly well laid out the final three contributed chapters.

A forest stream in the Czech Republic Image: Dominique Cappronnier | Flickr Creative Commons



In your synthesis, you note that the world has entered a new geological era, the ‘Anthropocene’ where human activities take on the magnitude of natural, geological and climatic processes in affecting Earth systems.  Interestingly, you state that “Nowhere is this truer than in aquatic ecosystems”.  How is the Anthropocene era evident in aquatic ecosystems?  And does the naming of the Anthropocene era change anything in how we study, understand and manage freshwaters?


The simple reality is that freshwaters have always been a focal point for human development, and as the world population continues to grow, we continue to make demands on these distinctly finite resources. In blunt terms, humans have been very successful plumbers. We continuously try to compensate for the fact that fresh water is unevenly distributed in space and time, and one of the emerging hallmarks of the Anthropocene is the human alteration of the global hydrologic cycle. And accompanying these movements and delays of freshwater flows via dam construction, irrigation, groundwater withdrawals, inter-basin transfers, substituting in ditches or drainage systems for natural channels, and so on are distinct changes in water quality and in ecosystem processes.

Because fresh water is a relatively limited global resource, the conflicting challenge of providing sufficient water of sufficient quality for human needs while maintaining freshwater ecosystems has sharpened. Trying to manage this conflict in a sustainable fashion has clearly been inspiring research over the past 1-2 decades, and we hoped to capture some of this work in the book.  I think by putting a label on it – the Anthropocene – underscores the value and urgency for data and research needed to sustain freshwaters.

While many people have reflected on this point before – and more elegantly than me! – I’m struck by the transition that has occurred over my scientific career, and even over just the last 10 years. As a graduate student, research on topics such as nutrient cycling or surface-groundwater interactions were purely academic in nature and most researchers worked in relatively protected places to minimize confounding and annoying effects of human influence. I can’t even remember hearing talks on, for example, urban streams. Now, several years later, this basic research continues – and must, because we need to understand the fundamental workings of ecosystems.

But there has also been a huge shift to working in human-dominated ecosystems and to ask questions about the nature of this human influence. This includes incorporating a forward-looking perspective in science and management – how do we manage freshwater ecosystems and meet human needs for water now, a decade for now, or a century from now? In short, as researchers and managers, we are rising to the challenge of the Anthropocene.

An urban stream in Colorado. Image: Mick Chester | Flickr Creative Commons


Following on from the last question, I see an underlying theme of the book as being how stream ecology can have intellectual and practical interchanges with environmental policy and management in an era of increasing uncertainty.  How can these interchanges be most productive, do you think? What can aquatic ecology offer in terms of addressing social needs and environmental problems?

This is a great question, and one that is tough for me to answer! As I mentioned above, there has been a lot of growth in the field over the past decade in terms of developing new tools, models, etc. that are providing us with new power and new opportunities to ask questions about how streams and rivers work, and how best to manage these ecosystems. And as we tune in to the challenge of freshwater sustainability, I think it’s safe to say that most researchers are interacting with managers and policy-makers far more often than in the past.

Again thinking back on my own history, interactions with these groups was almost completely absent until the last 15 years. Now it is a fundamental part of my work, and we routinely include agency researchers and managers in our projects. That said, I think we are all still learning how to produce good science and useful science, and how to be most effective at informing decision-making with scientific understanding.

It’s great to see some emerging behaviors and practices becoming routing that should help facilitate these interactions. These including things such as data sharing and open data access, training opportunities for scientists to improve our communication skills with non-scientific audiences (journalists, policy makers, local stakeholders, etc.), and research initiatives that explicitly embrace integrated social-ecological approaches and questions.

Purchase a copy of ‘Stream Ecosystems in a Changing Environment’ here.