Kricher explores the tropics

Professor of Biology John KricherProfessor of Biology John Kricher, an expert in ornithology, has been studying and teaching about the tropics for more than three decades. His newest book is Tropical Ecology (Princeton University Press, 2011). The 632-page color-illustrated textbook offers a comprehensive and accessible introduction to the subject for advanced undergraduates and graduate students. Senior writer Hannah Benoit talked with him about the book.

Define “the tropics.”

The tropics comprise the region between the Tropic of Cancer and the Tropic of Capricorn. This region has the highest amount of sunlight throughout the year and is therefore warm all year. There is more photosynthesis per unit area in the tropics than outside of it, and there are many more life forms in the tropics than elsewhere. There are major tropical landmasses such as the vast Amazon Basin and African Congo as well as parts of India and mainland Asia. In addition, there are numerous tropical islands, most in archipelagos such as Indonesia.

How did you become interested in this topic?

I was drawn to the tropics [in 1978] through an opportunity to do a course in Belize. Wheaton’s then president, Alice Emerson, was strongly supportive. So I plunged ahead, knowing relatively little about tropical ecology but eager to learn along with my students. Thirty-three years later, alums continue to talk about that first course. [Read the story on page 18 to see how the course influenced an alum’s career choice.] I continued to teach it and have since explored Peru, Ecuador, Trinidad and Tobago, and Venezuela to learn more and more about tropical ecology.

Why did you write this book?

Tropical Ecology by John KricherMy earlier book, A Neotropical Companion, focused mainly on the Middle American tropics. Many college courses in tropical ecology adopted it, but there was still a clear need for a college-level comprehensive textbook on tropical ecology, and my editor asked me to take it on. Tropical regions offer outstanding opportunities to research and to learn how complex interactions occur among species that have profound effects in structuring ecosystems and in how our very planet functions.

What can tropical ecology teach us about life on Earth?

The key to tropical ecology is in the complexity of relationships among the myriad of species present. No other ecosystems, natural or otherwise, rival the tropics in the number of species of plants, birds, mammals, insects, microbes, etc., that you find in just a hectare of forest. Well over 50 percent of the world’s species are found only in the tropics, even though the total area of the tropics is proportionally far less than that. There are 20 to 30 species of trees and shrubs in Wheaton Woods. But if we moved Wheaton to, say, Amazonia, we’d have 200 to 300 or more species of trees and shrubs in the same amount of area. We’d be able to discover new species of insects and various other forms of life.

Why is biodiversity important?

Biodiversity is important to life on Earth because it is life on Earth; it is what we share the planet with. The various life forms, in their combined and complex activities and interrelationships, are responsible for keeping everything—from the atmosphere to soil and water—relatively stable. We call this collective effect “ecosystem services,” and these services depend on biodiversity to supply the labor. It is astonishing that we have reached a point in Earth’s 4.5-billion-year history where one species, one genome, namely Homo sapiens, has significantly altered and perturbed such global processes as regulation of carbon dioxide in the atmosphere and oceans. We need all the help available to maintain a stable Earth, and biodiversity does that. Earth is a living planet, and biodiversity is the expression of that life. We also have a collective responsibility to foster and to honor our intellect, unique among all forms of biodiversity, and to develop a strong aesthetic appreciation for other life forms, just as education introduces us to the joys of fine classical music, art and literature. Tigers are worth having on the planet because any educated person should be able to regard such animals with a mixture of profound awe and admiration. And from such an understanding should come the realization that such creatures lay some claim to this planet, too. We should honor that and assure their preservation.

Why did you include a chapter about human beings as part of the ecology?

It has always impressed me how Western culture (and probably other cultures, too) seems to recognize a dualism between humanity and nature: us and them, and usually us versus them. Such a view has strong historical roots. Like all life forms we must somehow wrest our material needs for food and fiber from nature. Nature often does not give up such resources easily, and thus human ingenuity is required. For example, in Bali some years ago I was deeply impressed by how the culture had so successfully maintained the rice paddies for generations, a complex social system maintaining a complex ecology. At the same time, I saw virtually no birds in the forests of Bali because they were either outright gone or captured and kept in cages. I saw more species of birds for sale in the market in [the town of] Ubud than in the forests around it. It is not possible to fully understand tropical ecology without understanding the historical and current impacts, some good, some not, exerted upon it by the collective energies and agendas of the humans who claim ownership.

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