Expert Q&A: Dr. Stewart T.A. Pickett

Steward Pickett is a Distinguished Senior Scientist and plant ecologist at the Cary Institute of Ecosystem Studies. He directs the Baltimore Ecosystem Study Long-Term Ecological Research program. His research focuses on the ecological structure and function of urban areas, the linkage of riparian corridors and savanna in the Kruger National Park, South Africa, and the dynamics of vegetation. He has contributed books on natural disturbance, ecological heterogeneity, humans as components of ecosystems, conservation, ecological urban design, and the philosophy of ecology. He has served on the boards of the Ecological Society of America and the American Institute of Biological Sciences. In August 2010, he will become President elect of the Ecological Society of America.

The Baltimore Ecosystem Study is one of 26 research programs (24 in the U.S. and two in Antarctica) that make up the Long Term Ecological Research Network established by the National Science Foundation to study ecological systems over long time periods. For the purposes of this project, how long is “long-term?”

The LTER started in 1980 with the understanding that ecological processes take a long time to play out. Sometimes events in ecosystems have a response that you don’t see right away. The National Science Foundation gradually grew the network so that it encompassed a number of different kinds of habitats-deserts, forests, alpine, tropical, etc.  The intent is for these projects to run for decades-something on the order of 50 or 60 years, because of the slowness of ecological processes.

The Baltimore project started in 1997. About a year before that, the National Science Foundation announced a competition for up to two urban LTER sites. Over 20 organizations submitted proposals, [which were reviewed by] a multi-disciplinary panel that included biological scientists, social scientists, and all sorts of ecologists. The Baltimore project was one of two projects chosen. The other was Phoenix. So the short answer is that our proposal rose to the top of the list.

One of the things that attracted us to Baltimore was that there was already an organization in place that was providing a bridge between communities, agencies and environmental information – the Parks & People Foundation.  Some of the other places we considered didn’t have that kind of wonderful, institutional capital. Another thing about Baltimore that was very helpful to us is that watersheds are something that many of the organizations-and certainly the governments-in the Baltimore metropolitan area recognize as important and watersheds are one of the main tools that ecologists use in these long-term, ecological research projects. Another advantage of Baltimore is that it’s a decent size metropolitan area, but it is relatively simple in its jurisdictional structure. I have worked in the New York metro area before, and that has three states, 31 counties, and all sorts of other authorities.

How far back in history does the study look?  

We have a lot of historical information, which is another advantage of Baltimore. Our colleague at Johns Hopkins, [BES Co-Principal Investigator] Grace Brush, is a well known paleoecologist. She has done sediment cores and column studies in the Baltimore area and out in the Chesapeake Bay. Having that very, very long-term history has been extremely helpful to us. She and some of her graduate students have performed historical analyses of large estates [in the region]. It has been very useful to see how the imprint of those property boundaries still plays through in some of the special heterogeneity that is structuring Baltimore now.

We have historical geographers and an environmental lawyer in the project as well. Geoff Buckley at Ohio University is studying how Maryland came to have a state forestry division, one of the earliest in the country. That was a very progressive thing to do and it influenced the structure of the vegetation in the Baltimore metro area historically. Our environmental lawyer, Charlie Lord, has done studies that document how some of the inequities of racial segregation actually developed. That has been very useful because it demonstrates causation – the actual political actions that contribute to neighborhood segregation, rather than just correlation.

For demographic and social data, of course we have the census, which is a remarkable record. Our social scientists have been very clever at dissecting the recent census information in a way that helps us understand fine scale social differentiation and relate that to ecological processes and conditions.

Most older cities are heavily burdened by combined sewer overflows, while Baltimore has very few. Why wasn’t a city with this problem chosen?

You have to know what the nature of the infrastructure is to do an ecological study in an urban area, but you don’t necessarily have to have it be one way or another. It didn’t matter to us that Baltimore did or did not have a particular kind of sewer system. We just had to know what kind it was.

The goal of the study, as I understand it, is to “develop a thorough understanding of metropolitan Baltimore as an ecological system” and share that understanding with educators and decision makers. In working towards that goal, the study seeks to answer three central questions related to fluxes, relationships and linkages.  Why those questions? How will they lead to such an understanding?

Those questions, when broken down to their basic components, are the fundamental questions you’d ask about any ecological system: How is it put together in space? How does it change in time? What are the processes going on inside of it? How is it connected to processes outside? How does that spatial structure you discovered in addressing the first question influence the processes and fluxes of materials and energy? Finally, what does that knowledge imply about how people might design, restore, or simply understand themselves as part of the ecosystem?

We wanted to show the National Science Foundation that we were doing ecological science combined with social science in what was, for them, a new arena. We didn’t want to make it sound like something that was completely different. Most ecological research, with some exceptions, had been done in what we’d call wild areas, managed landscapes, or working areas, but not in cities in the United States.

How does this differ from the Phoenix study?

They do some pretty similar things. One of our initial, conceptual frameworks was patch dynamics. Patch dynamics is a set of concepts and theories that recognizes spatial differentiation in ecosystems and landscapes, and suggests that the spatial pattern is important to how the systems function and change. Each patch can change because of interactions within it and interactions with other patches. Urban systems are known to be socially and economically patchy. We could add ecological understanding to that and develop a view of Baltimore as a changing patchwork of socio-ecological structures and functions – patch dynamics. Phoenix also used that. It was interesting that both sites used that framework without knowing the other was planning to do so.

(Change in land cover from 1970 to 1999 in a suburban area of metropolitan Baltimore, MD. Typical is the loss and fragmentation of forest, the increase in residential and transportation land in such areas.)

Patch dynamics is the concern with spatial heterogeneity within ecological systems at various spatial scales. A watershed is an example of a type of patch. Recognizing that these patches can shift in size, content, structure, boundaries, etc., we can ask questions like, “Are the social patches similar to the ecological patches? Where are there similarities?”

People are everywhere now. Why are the other 24 sites not required to incorporate any social dynamics in their studies?

I’m happy to say that over the time that we’ve been active in the LTER Network, there has been a growth in that larger network of understanding the need to incorporate institutions, human decisions, and remote impacts or effects of people outside the system. Now, the National Science Foundation is encouraging all sites to figure out how people interact with their ecological processes.

Can you give us some examples of how you’ve been doing that in the BES?

We have been looking at people’s environmental understanding and behaviors in various neighborhoods throughout the metro area. We conducted a social survey. We maintained people’s privacy, but we learned what kinds of understandings people have about the environment throughout the metro area. We can relate that to what kinds of purchasing decisions they make. We can assess how much, for example, people are investing in lawn care, or how much they say they value outdoor recreation. We can relate that to where they live and what kinds of things they want in their neighborhoods. Then, we can relate all that to some of the environmental processes that are going on in the neighborhood. We can say, “To what extent do people’s desires and purchasing decisions play forward into ecological processes?” That’s what we’re actively engaged in right now.

Another example of people’s social and environmental interactions is how people value parks. You can figure that out by looking at home values. You can figure that out by asking people about their perceptions of safety associated with the parks. We found that it is not uniform throughout the city. There are some really interesting social drivers of how people value the parks. Not all parks are equally valued.

What were some of the things you discovered about the way people value parks in Baltimore?

There is a lot of valuation that relates to the perception-not necessarily the reality- of crime. That crime is higher closer to this park or that park.

One would assume that public parks play a critical role in keeping that system alive. Yet here in Baltimore, parks are underfunded and losing budget. There is also very little regeneration in many city parks. Is your work influencing policy or other decisions related to parks?

We are often in conversations with managers and policy makers within the various jurisdictions. It’s more a dialogue with them to find out what certain things they pursue and then we share things we are learning. We don’t go to them and say, “You should do this.” We’re not engaged in that kind of relationship.

The folks in the City Parks and Recreation department, for example, are very concerned with regeneration in the parks. We haven’t really yet done some of the studies that we think will help understand that but we have done some preliminary work on what comes into some of the canopy gaps when older trees die. There is a lot of concern about invasive vines. Some of our members have been in conversations with folks within the Recreation and Parks Department about how to help with their management strategies. But there’s still a lot more to do.

How can the information garnered from the BES be applied to other urban areas in the region, country, and world?

Baltimore shares some characteristics with a lot of cities that have made a transition from an industrial economy to a service economy. If you look at many of the old, industrial powerhouse cities in the U.S., that’s the case. A lot of our work should translate very readily to those kinds of cities.

There are also some characteristics of the Baltimore metro area, such as the nature of the suburban areas, the potential for the increased role of green space, and the improvements in management of stormwater and canopy cover, that can also translate. There are a lot of cities-even those that have not had the experience of transitioning from an industrial to a service economy- with similar structures and dynamics.

Are there ways in which the intersection of environmental and social issues in Baltimore are unique, and potentially not generalizable?

Some of the characteristics of Baltimore are seen in many cities, such as increasing segregation, the disjunction of population centers from employment centers, issues of health related to maintenance of old housing stock, issues of access to services and recreational facilities. You see intersections of those kinds of social and environmental concerns in a lot of different cities. I think, in fact, Baltimore is not so unique in that way.

If you start thinking about the incredible wave of urbanization that is occurring in the galloping economies of India and China, the structure of cities there is going to be different. The structure of economic drivers in those cities is going to be different than it is in the history of Baltimore, Detroit, or even Atlanta or Phoenix. There are going to be some things internationally that will be different, but there is a lot in Baltimore, in terms of interactions between social and biological processes, that really does translate to many, many cities.

Unlike the other sites in the LTER network, the BES is required to incorporate human population, social institutions, and social dynamics in its work. Why is this required for this site and not others? How are you doing this? Can you give us a few examples?

We are required (by NSF) to collect high quality data and document: biological primary productivity, mineral nutrient dynamics, carbon dynamics, important biological populations and natural disturbances in the “ecosystem” that is Baltimore. But we are also required to understand human population structure – age, ethnicity, distribution of knowledge and resources, and the way people are aggregated into neighborhoods and organizations.

We are conducting research on how decisions are made by households and organizations, what are the human values and lifestyle characteristics that drive those decisions, and how the decisions affect other ecosystem processes. Ultimately, understanding the feedback loop between people’s values, perceptions, social resources, and environmental conditions and processes is the goal of our joint social-ecological research. It would be impossible to understand an urban area ecologically without working out the social-ecological feedback.

An example of a social process that is being investigated to understand this feedback is the “ecology of prestige.” This phrase was coined by Morgan Grove, one of the social scientists with the USDA Forest Service who works on BES.  The phrase indicates that people’s actions that bind them to neighborhood values by adopting, for example, certain kinds of landscaping practices and yard aesthetics not only are socially important, but that these actions have environmental consequences. Domestic water use and application of nitrogen fertilizer are two examples of environmentally important results of lifestyle choices.

Who does the data collection? How is quality verified if there are many different data streams?

We have technicians who are responsible for some of our core data. They input the data into our data management system. In these cases, we go through a long process to make sure that the stuff we post is correct. We check for outliers. We calibrate the instruments. We periodically have internal checks in the laboratory for the quality of the chemical analyses that we do. We use pretty standard procedures for our core data sets.

For data sets that are collected by various contributors to BES that have come through laboratories other than our own, we have to depend on them to do the quality assurance. Our information manager does a check to make sure that the data aren’t looking squirrely. Sometimes they do, and the contributor is asked to go back to his or her raw data and make sure everything is correct.

We have a number of different ways to check the quality of the data. [We follow the standards of agencies such as the USGS, EPA, NRCS, etc.]  We try to stick to the book, and then we have our information manager check things. One of the best checks is when we publish the information in the peer review literature and have our conclusions checked by reviewers.

Can this data be accessed by the public? Are peer journals the best way for people to do so?

That’s one way. That will get people to the summarized data and analyses. Even though they are technical papers, that information has been digested, so with a little help, someone can understand it. The raw data are available on our web site.  We do protect graduate students and postdoctoral researchers. The data they are involved in collecting is not released right away because we don’t want some other scientist to take it and publish what a graduate student has been planning to be their dissertation. That would be a pretty big disaster. So not all of the data are instantly available, but once people finish working with it, we make it available. We currently are revising our web site so that people can search our data more easily, but there are a lot of data that are available on our web site already.

Even before data are released to the public, if they haven’t been worked up and published by our crew, if a potential collaborator from the city or one of the counties wants to work with us, we share that information. We are always interested in substantive collaboration, and the data are part of the bridge building for that.

Can people access the data from the social survey you mentioned earlier?

With social data, privacy is protected, as we are required to do by federal regulations. So you can’t go in and identify what individual property occupants are doing. But the survey data are available.  (Search for theme keywords“social survey.”)

Can you talk about the differences in collecting environmental data and social data and the challenges involved in connecting the two?

The big challenge is that a lot of social data are organized around the census geography. That’s very coarse scale geography relative to a lot of ecological processes we’re discovering to be important in the metro area. Our social scientists and social scientists elsewhere are working on this problem. There are some clever ways to interpolate within the coarse scale sense of geography.

Another problem is that sometimes with the field environmental data, we need to figure out what the water relationships are from a particular hillside that may be occupied by a handful of parcels. So getting permission, being able to enter, and setting up equipment in a way that doesn’t interfere with aesthetics or annoy people can be difficult.

These two kinds of problems are some of the reasons why urban ecology is not easy. Getting the scales to match is the big issue from both a social and ecological perspective. Getting data collected in ways that don’t annoy people, get in their way, or put our equipment at risk is tricky.

Katalin Szlavecz from Johns Hopkins is doing some really cool work with remote data. She has these little soil sensors out that tell you moisture and temperature and they broadcast the data back to a central location. She’s trying to figure out how to make those work better and be less conspicuous.

As you see greater acceptance of integrating social and environmental data, do you think the problem of getting scales to match will go away?

Making that problem go away would require a big investment. For example, even a relatively small a watershed, say 15 hectares, rather than having one gauging spot, you’d need ways to measure the water budget throughout, so you’d need to increase the density of sampling. That would mean more equipment, more people, and more data streams to store, manage and check quality on.

Can you share any major preliminary findings or surprises (e.g., patterns/interactions that one would expect but haven’t been detected, or patterns detected that weren’t anticipated)?

One of our earlier findings was that nutrient loading in streams was higher in suburban areas than in older, denser areas within the city. That was an unexpected surprise. We’re trying to sort out to what extent that is related to fertilizer differences or septic tanks.

Another finding that surprises some people is that although there is a theory which comes from international development that people who have relatively low economic resources are not likely to be concerned with environmental quality, we found through our social survey that this is not the case in Baltimore. We found that there is concern for environmental quality among all social groups in the Baltimore metro area.

We’re finding that there are some neighborhoods where the vegetation-specifically the amount of tree canopy-is higher than one might expect based on the expenditures that people are making on landscaping. We’re trying to sort out to what extent these are legacy landscapes resulting from the decisions of previous occupants, or to what extent these are volunteer trees.

One of the interesting things we found is that even with this pattern of higher than expected nitrates in streams in urban areas, if you look at the suburban landscape in general, it does contribute to the retention. If you do a nitrogen budget figuring out what is coming in by fertilizer, what’s coming in from the atmosphere (pollution thrown up by cars, for example) and what’s coming out through streams, you find out that suburban areas do contribute to the retention of nitrates in the system. The green areas within our urban matrix are doing good work in reducing the nitrate that is headed toward the Chesapeake Bay.

Another big surprise was the function of riparian areas. I’m focusing on nitrogen because that nitrate is such an important pollutant in the Chesapeake Bay. The literature on riparian zones that preceded urban focus said that riparian buffers really help you control the nitrates that are coming into streams. Some of that pioneering work was done in Maryland agricultural landscapes. When we take that idea into the city, we find that, in fact, the urban riparian areas that still exist (keep in mind that most urban riparian areas were put into pipes long ago) have been disconnected from the water table, their organic matter has declined, and because they are now drier, the oxygen in the soil is high rather than low. The bacteria that do the work of converting the nitrate to the nitrogen gas require very low oxygen flow. So it was a surprise to many people that these urban riparian areas were not doing that work. Policy makers who were in dialogue with us said, “That means the strategy that everyone has been talking about to restore riparian areas isn’t enough in urban areas unless you can restore the hydrology.” So the policy folks-from the City through the State-said that in urban areas, we need to work with the whole watershed. We need to reduce stormwater flow, which is the vehicle that moves nitrate around, and work throughout the watershed to increase areas where you might be doing this conversion. So you really have to think about extending your management well beyond the riparian zone. That was a surprising scientific finding, and the dialogue with policy makers led to a shift in the way they were thinking about that kind of management.

As the BES is a long-term study, I’m assuming it must grapple with climate change and sea level rise, and how the area deals with stormwater, waste, population migration, etc. How are you incorporating climate change? Does the study reveal any predictions?

That’s an interesting question. We are ending up our second phase of funding this year; we have just applied for an additional six years. One of the things we have added is more of a concern for climate change. We have some people now working on the project who have already been very active in Maryland in understanding the sea level rise issues from the social perspective. We have some new economic modelers who are joining the project who are interested in working with that social information and physical projections of sea level rise and what that means for the coast infrastructure.

We are going to be doing some scenario modeling in collaboration/dialogue with policy makers in the metro area, and that’s going to be new for us.

If funding were to run out tomorrow, and someone asked you for your best-guess answer to those three central questions of the BES, based on the work you’ve done on the study to date, what would your answers be?

For the structure of the metro area, I think we have confirmed that the relatively fine-scale to medium-scale heterogeneity is important to how the ecosystem functions. That is different from how people approached urban areas before. They had approached urban areas as a big bucket. They looked at what came in and what went out. What we’re saying is that the physical, three-dimensional structure of what’s in the bucket is crucial-from both a biological and social perspective.

In terms of the fluxes, we have documented the surprising contributions of the biological components of our urban system to what we call in ecology “ecosystem retention,” the capacity of ecosystems to slow down the flow of limiting resources, which often end up being pollutants. Being able to point to aspects of the larger metropolitan system that contribute to retention of limiting materials is an important finding.

How can people use this information? The story of how people used [the riparian buffer information] is a good example. We have helped the City of Baltimore, and some other cities sort out their goals for increasing tree canopy, which is something that will help with stormwater, climate moderation and climate storage. We also have ecological information feeding into some of our public school curricula. We are finding that that information is a way to help stimulate the engagement of kids in all kinds of neighborhoods with their environment.

Can Baltimore’s current zoning code rewrite process – TransForm Baltimore  – be part of building the city’s adaptive capacity as an urban ecosystem?

It would be useful to have a conversation with some of the folks who are involved in the code rewrite and see if there are ways to think explicitly about the ecological implications of the things they are thinking about. Zoning is a fairly coarse-scale filter. Often, what really makes a difference are the regulations of what you can actually do on a particular parcel and whether people are required to do certain things on site, such as stormwater management. I think there are opportunities for the regulations in our various municipalities to permit some things that haven’t been thought about. I do see, in the zoning outline, an appreciation for mixed uses – social and economic. It’s important to think about how those mixtures can feed forward into environmental quality. With the City’s Sustainability Plan standing behind the zoning regulations, I would hope that those kinds of connections are kept in mind as the language of the zoning is rewritten.

How would you characterize Baltimore’s current level of ecological literacy?

I have been very impressed with the City and county governments’ concerns with watershed management. There will soon be a meeting to work through some of the future of Baltimore City and Baltimore County’s joint watershed agreement. That requires a very high level of understanding and, more importantly, commitment. That is remarkable and unusual. Most cities and counties don’t even recognize that they have watersheds, much less that they share them.

Another place in which I see a high level of literacy is in the remarkable political leadership that got the sustainability effort moving in the City and [Baltimore] County. Everyone thinks about cities like Portland, Seattle and Chicago when it comes to sustainability. I think what’s going on in the Baltimore metro area with regard to sustainability aims very high, and the process by which they are generating sustainability plans is very well informed and socially inclusive. Those are things that speak to me of a high degree of literacy.

Among the general public, it’s not quite as impressive. But there are some real bright spots of knowledge. [For example,] when I participated in Baltimore City’s Sustainability Plan  effort, I saw middle school kids coming before the city council to make a presentation about what they were thinking about in terms of sustainability.

Our partnership with Parks & People and their Community Greening programs  allows us to interact with a number of different communities in the City. We also have worked with public and private schools to help develop environmentally-informed curricula and put them into practice.

We don’t have the resources to have a science writer constantly engaged with us. It’s difficult for us scientists to write for the public, and it can also be hard to find an audience. This is not always something the local media is jazzed about. We are always working on improving our public information flow. In our project reviews, the National Science Foundation has been very happy with what we’re doing and the way we are doing it through dialogue.

What role can urban agriculture play in the ecosystem that is Baltimore?

Urban agriculture is a very hot topic these days in urban sustainability, quality of life, and health. Urban agriculture has a real role to play. I know that it’s an issue in BaltimoreCity’s Sustainability Plan, and it’s a great thing. You need to be very careful about what soil is used, though. We do have some studies of lead and other heavy metal contamination in various neighborhoods.

I did want to ask if you are studying any issues related to Baltimore’s industrial legacy – lead in soils, reuse of contaminated sites, etc.

We mostly study formerly residential, vacant property. Unfortunately, we just can’t do everything.

Have you studied salinity levels in drinking water reservoirs?

The city has long term data on salinity of streams draining into the drinking water reservoirs. BES researchers partnered with scientists and managers from Baltimore City and USGS to analyze the data. We also combined the trends in Baltimore with data from other areas in the northeastern US, and discovered some disturbing trends. Although the water is still safe to drink, the streams deliver water that is as much as 25% the salinity of seawater during the winter de-icing season. And the water draining city and suburban areas remains much more saline than non-urban, forest streams even during the summer. Levels of salinity are already high enough to impair stream organisms, and if the rate of increase continues as it has in the past, the quality of water for drinking will be impaired. (See Kaushal, et al. 2005. Proceedings of the National Academy of Sciences [USA] volume 102, number 38, pages 13517–13520).

How are invasive species affecting the ecology of Baltimore?

I’m going to be that famous, two-handed scientist. On the one hand, many of the invasive species are well-adapted for dealing with environments that we people generate. Some of these invasive species (I’m thinking mainly of trees) are tolerant of low oxygen levels in the soils. There are trees growing out of tree pits and sidewalks, and that’s a tough life. Some of the exotic species are good stress tolerators, so some of them are providing the benefits of green in the city that would be hard for some of our more sensitive species to deal with. So on that first hand, there are some benefits of exotic species.

On the other hand, there are some specific exotic species that are real, real problems. I can’t say that we just want to get rid of exotic species and only use natives. But we have to be a lot more careful of introducing exotic species. People are accidentally introducing new insects that are going to have big impacts on our forest structure. Emerald Ash Borer  is a big problem in the deciduous forest region of the United States. Some of the exotic vines that were introduced are a big problem in the regeneration of native trees.

Is there an invasive species you consider to be Enemy Number One here in Baltimore?

Japanese knotweed, a de-stabilizer of stream banks, is a big problem in Baltimore. There are also things that are still being planted that are damaging our forests. Norway maple is an example. It comes out early, stays late, has dense shade, and seems to have some chemical inhibitions, so it really impacts the forest understory.

What is your opinion on daylighting streams in urban areas?

There are some advantages to daylighting streams. If you can restore the banks in ways that you get some interaction between the stream and adjoining land, you can improve their nitrate retention capacity. There is also simply the education value of letting people know that water is a part of the city. Certainly, daylighting streams has value in improving biodiversity by opening things to daylight, allowing organic matter to come in, bacteria and insects feeding on that that weren’t there before, fish populations, etc.

We just had an historic snowfall in Baltimore. How do major events like that affect the ecosystem that is Baltimore?

We haven’t really talked through what it might mean. Big events like that might have some policy implications that affect how people manage the environment. I haven’t really talked with our social scientists to think that through. Often, “natural events” like that, result in management changes. The rain associated with Hurricane Agnes in 1972 changed how people managed and developed on floodplains. That is an extreme example. How a big blizzard might affect the environment down the line is a little less clear. It might be something that is worth looking into.

Our firm, and many of the people with whom we work, are focused on regenerating natural systems and re-establishing links that connect those systems with people, plants, animals, habitats, infrastructure, economics, culture, etc.  Based on what you’ve learned so far, do you have any words of optimism to offer us as we work toward the goal of regenerative outcomes?

That’s a really important goal: making it clear to people that they are part of a larger ecosystem- that even the built environment has in it ecological processes-and that they can, through their behaviors and political and organizational choices, help enhance those processes and  contribute to sustainability, improved human health and improved environmental health.

I like the word “regeneration” because it doesn’t suggest that you have to go back to some single, historical point as your reference. We’re dealing with really new systems, and to try to force the clock back to some year in the past is probably not wise. We are dealing with systems that are without precedent, and thinking creatively how to make these hybrids between nature and intentional and accidental human intervention work better in the sense of sustainability is crucial. Regeneration is a great way to frame that.