Faculty Profile

Dan L. Perlman
April 1, 2006

Dan L. Perlman teaches at Brandeis University, in Waltham, Massachusetts, where he is chair of the Environmental Studies Program and associate professor of biology. He has coauthored three textbooks on conservation biology and ecology: Practical Ecology for Planners, Developers, and Citizens (with Jeffrey C. Milder, published by Island Press in cooperation with the Lincoln Institute of Land Policy, 2005); Conserving Earth’s Biodiversity (an interactive CD-ROM with Edward O. Wilson, published by Island Press, 2000); and Biodiversity: Exploring Values and Priorities in Conservation (with Glenn Adelson, published by Blackwell Scientific, 1997).

An avid nature photographer, Perlman’s photographs have been exhibited at the American Museum of Natural History in New York and the Museum of Science in Boston, and he has been the photographer for two children’s books (one on a Costa Rican rainforest and the other on ants). He recently launched a Web site from which he freely distributes teaching materials he has developed for ecology and environmental studies, including his photographs (click here). He has received university-wide teaching awards at both Brandeis University and Harvard University, where he taught conservation biology part-time for nine years. He holds a Ph.D. from Harvard University’s Department of Organismic and Evolutionary Biology.

Land Lines: How can ecology help planners, landscape architects, and others in the planning and design community?

Dan Perlman: The study of ecology reminds us that humans are truly a part of nature, although in our highly technological society it is easy to forget how closely our lives are tied to the land and other elements. Most of us are only reminded of these close interactions when nature unleashes her fury through a hurricane, tornado, flood, or earthquake. Given that the planning and design professions aim to make humans lives as healthy and fulfilling as possible, it is critical to attend to nature when changing the landscapes where we live and work.

Once one understands some basic concepts of ecology, it is no longer possible to view humans as being divorced from the ecosystems in which they live. Like all other organisms, humans interact with the plants and animals around them, and with the nonliving aspects of ecosystems, such as rain, wind, and fire. Unfortunately, when we design human communities without considering the particulars of the ecosystems in which they are embedded, we place people in dangerous and unhealthy situations. With a little ecological knowledge, however, planning professionals can improve human lives.

Land Lines: What aspects of ecology are especially pertinent to planners and designers?

Dan Perlman: Over the past few decades, ecologists have begun paying close attention to disturbance regimes—the natural processes that randomly change ecosystems. It turns out that disturbances greatly affect humans as well as the plants and animals around us. In recent years it has become ever clearer that ecological disturbances such as hurricanes, forest fires, tsunamis, and earthquakes have the potential to devastate human communities.

By understanding the ecological histories and disturbance regimes of the specific landscapes in which they work, planning professionals can ensure that they do not place the human population in harm’s way. While homes placed along Gulf Coast beaches or deep in the pine forests of the West are desirable to many, recognition of the dangers of hurricanes and fire will lead planners to either steer development away from dangerous settings or to create protections for the people living in potentially dangerous situations.

It is critical to remember, however, that landscapes differ in their disturbance regimes and the frequency and impact of their typical disturbances. It makes sense to focus on earthquakes, landslides, and fires in the hills of southern California and on hurricanes in Florida, rather than vice versa, for example, since those types of disturbances are most likely to occur in those locations.

Land Lines: Ecologists and conservation biologists are often accused of sounding alarm bells. Do they also offer positive visions for the future?

Dan Perlman: Actually, there are many positive aspects to increased understanding of ecological processes. Intact and healthy natural landscapes perform critical ecosystem services that would be extremely expensive or impossible to replace through technological means. Water filtration, absorption of air pollutants and greenhouse gasses, and soil protection are just a few of the many services that nature provides.

Psychologists recognize the mental health benefits of being able to interact with nature, and planning professionals can help make these benefits widely available by incorporating easy access to natural areas into their designs. Many recent studies have demonstrated that proximity to natural areas is very attractive for wide cross-sections of the populace—along with being economically valuable. In addition, being able to interact with native habitats and organisms, or even just knowing that they exist, can contribute to the mental health and well-being of people of all ages. It is especially important that young people have opportunities to experience and learn about nature so they can integrate that awareness into their future decision making about where and how they live.

Land Lines: How can the conservation of biodiversity be balanced with the needs and desires of the house-buying public?

Dan Perlman: The goal of conservation biologists is to protect and restore healthy native species and ecosystems. New York City’s recent efforts to protect its water supply through a variety of land protection programs around the upstate watersheds and reservoirs in the Catskill Mountains is a great example of balancing human and ecosystem health. By sensibly guiding development to specific areas and limiting it from ecologically fragile areas or areas that are especially important for human health, planners and policy makers can obtain real benefits for both humans and ecosystems alike.

If we also consider the well-being of nonhuman organisms and creatures that share our planet, we find that attention to conservation biology during planning can pay major dividends. Biologists know that small nature reserves isolated in seas of human development are not an effective way to protect the native plants and animals of our landscapes. Instead, wherever possible, we should create large protected areas that can support populations of larger animals, many of which play especially important roles in the functioning of healthy ecosystems.

In addition, there is some evidence that intact habitat corridors, if well planned, can link smaller reserves into networks that may approximate the functions of large reserves. If planners begin their considerations with these concepts in mind, they may be able to create healthy, diverse landscapes. It is difficult to create or protect large reserves and corridors once development has begun in earnest.

Land Lines: How will global climate change affect human health and safety, and what can planning professionals do to help?

Dan Perlman: As the global climate warms, the effects will vary considerably from location to location. Some regions will receive more precipitation and others less; some areas will become much hotter, some will only become slightly warmer, and some may actually become colder. Nonetheless, the broad outlines of the changes that can be expected over the next 50 to 100 years are becoming clearer.

The global average temperature will likely rise a few degrees Fahrenheit—and may rise even more than that—as compared to the approximately one-degree change that has occurred over the past century. As the oceans warm, the water will expand, leading to a rise in sea level. With increased warmth, the Antarctic and Greenland glaciers will melt more quickly, adding to sea level rise. As a result, coastal communities will be under threat and will either have to retreat inland or build expensive retaining walls and levees. If the Antarctic ice shelves (which hang over the ocean) break off, sea level will rise still further—and catastrophically quickly. Changing precipitation and temperature regimes will alter the basics around which communities are planned and built, and designers will have to plan in different ways. It is possible that extreme weather events, such as the major hurricanes of 2005, will become more frequent.

To help reduce the speed and amplitude of climate change, the United States will probably eventually join the international community’s consensus that carbon dioxide emissions must be reduced—and our communities can help reduce emissions by developing more public transit options and more compact development patterns. As an additional benefit, this may leave extra flexibility for setting aside and protecting natural areas, if human communities take up less of the landscape.

Land Lines: How has your work with the Lincoln Institute affected your thinking about conservation biology and ecology?

Dan Perlman: Most of my teaching is with college undergraduates. While I try to keep those classes well-grounded by bringing in guest speakers and taking field trips, I have found that traditional classroom discussions can become overly rarified. My first major project with the Lincoln Institute was to write the book Practical Ecology for Planners, Developers, and Citizens, with Jeff Milder. I found it really stimulating to be put in a position of trying to adapt and explain my scientific background to make ecological concepts understandable to planners, landscape architects, and planning board members. It is one thing to distill these concepts and discuss them with undergraduates, but it is quite different to present these ideas to professionals and decision makers who want guidance that is clear and actually useful.

As an outgrowth of the book project I have been involved in teaching and sitting on panels for several Lincoln programs. I have found that the professionals and practitioners taking these programs further challenge me to create a coherent and effective message. As with any stimulating group in a classroom, I find that I come away from these sessions with a sense that I have learned as much as anyone in the room.

Land Lines: From your ecological and conservation perspectives, what advice would you give a designer or planner today?

Dan Perlman: First, I would say that you should know the ecology of the region where you work. The ecological constraints and opportunities of Springfield, Oregon, are quite different from those of Springfields in Illinois, Georgia, and Massachusetts. There are no ecological prescriptions that fit all planning and design situations. As I learned early in my career, the First Law of Ecology is: It Depends.

Second, I would recommend paying careful attention to giving local residents easy access to nature—even to small natural areas of just a few acres. Adults and children flourish when in contact with nature, and there is no substitute for having small bits of native biodiversity nearby. I once heard Dr. Madhav Gadgil, the preeminent ecologist in India, state his wish that every child in his nation should have a little bit of wilderness near at hand. While his definition of wilderness may differ from that of ecologists in Boulder or Seattle, his hope is one that I feel deeply.