Professor Stanley Ivan Dodson died on August 23, 2009, following a cycling accident at the Colorado National Monument. His death is a stunning loss to all who knew him. Stanley is widely known by limnologists and ecologists for his groundbreaking work on the effects of size-selective predation on the structure of zooplankton communities, early studies on inducible anti-predator defenses, analyses of factors influencing species richness in lakes, and patient studies of cladoceran and copepod systematics. To his students and friends, Stanley will be remembered as an imaginative and gentle teacher and enthusiastic naturalist, with an ever-present smile and easy laugh.

After an early childhood in Illinois, Stanley grew up in Grand Junction, Colorado, where his father prospected for uranium. In this western setting, Stanley developed a deep interest in ponds, as well as a life-long interest in desert plants and landscapes. During many phases of his research, Stanley worked with pond communities and their fauna (see scientific contributions below). His work took him to ponds in mountain, desert, and Arctic environments, as well as closer to home in the agricultural landscape of southern Wisconsin. Beyond a profound understanding of freshwater animals and their habitats, Stanley was an outstanding naturalist and enjoyed identifying wildflowers, mushrooms, and birds. It took self-confidence in his own taxonomic skills to taste many varieties of mushrooms that he had only just identified.

Stanley was a professor at the University of Wisconsin in Madison for his entire professional career. He met his wife Ginny (also a PhD ecologist) when they were both undergraduates at Yale University in the mid-1960s. They raised a daughter (Sarah) and nurtured two grandchildren. After Stanley taught his young granddaughter Kate the scientific method [she documented the effects of different liquids (orange juice, milk, Miracle Gro, and distilled water) on the longevity of cut flowers], he proudly displayed her poster outside of his office.

Stanley loved to travel and took advantage of international meetings to visit colleagues in all parts of the world. His numerous hobbies included bicycling, gardening, fencing, music (violin), and Tai Chi. He was also active in his church community. Every group benefited from Stanley’s enthusiastic participation and service.

As an undergraduate at Yale University, Stanley performed research with John Brooks, resulting in a widely cited paper that was published a year before he graduated (Brooks & Dodson, 1965). This paper went on to become a classic foundational study in ecology. Stanley then completed his PhD work at the University of Washington, supervised by Tommy Edmondson. His PhD research on the roles of competition and predation in sha** zooplankton communities was novel and had many lasting impacts (see major scientific contributions below). Working at the Rocky Mountain Biological Laboratory in western Colorado, Stanley’s experiments demanded hard physical work, hauling supplies and water up steep mountain slopes, and his research was conducted in a primitive laboratory setting (Fig. 1). These experiences helped set the stage for Stanley as an advisor of graduate students at the University of Wisconsin.

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Doing graduate research on high altitude ponds in Colorado, Stanley Dodson worked under primitive conditions

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Stanley Dodson supervised and completed 22 PhD and 24 Master’s students [Supplementary Material 1], and over the years he maintained friendships with most of them. He continued to fertilize his students with new ideas at different stages in their professional careers. Stanley’s lab was also a welcome home to students from other universities, as well as four postdoctoral fellows (Fig. 2).

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Stanley Dodson with finishing PhD students Carolina Penalva (left) and Ken Forshay (right). Carolina was supervised by Rudi Strickler, but did much of her research in Stanley’s lab

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Stanley taught undergraduate courses in limnology and general ecology, as well as graduate courses in plankton ecology. He wrote a widely used textbook for limnology (Dodson, 2005), co-wrote and edited two books in ecology (Dodson et al., 1998, 1999), and co-authored monographs on zooplankton of the Laurentian Great Lakes and insects of Rocky Mountain streams (Balcer et al., 1984; Peckarsky et al., 1985). Colleagues and students at Wisconsin remember his imaginative teaching techniques, such as the time he convinced 150 undergraduate students to do the Tai Chi crane pose before their field trip to see wetland wading birds. Stanley’s classroom rendition of Daphnia feeding behavior is a local legend.

In recent years Stanley became very excited about a new method of giving presentations (“Beyond Bullet Points”) and, during his last several years as a professor, taught graduate seminars in presentation skills.

Stanley provided extensive service to the University, the local community, and to professional organizations. He served several years as Zoology Department Chair and supervised numerous students doing environmental internships. He led community field trips to restored wetlands and served on the board of directors for a local nature preserve. Stanley served on the board of editors for Hydrobiologia for 15 years. He also served on the board of editors for Ecology and for Ciencia Ergo Sum, and was a regular reviewer of research grant proposals and manuscripts for numerous other journals.

Major scientific contributions

Stanley Dodson had a knack for finding the important questions in modern limnology and designing simple experiments as critical tests. Stanley’s 109 published papers [Supplementary Material 2] were well read and often cited. A review of the Web of Science indicates that 16 of his papers were cited more than 100 times each and the paper by Brooks & Dodson (1965) has been cited 1,812 times (as of September 2009).

Major areas of influence are briefly described below. Following Dodson (1992), I use the term “lake” to include the full range of lentic bodies, ranging from small pools to the deepest lakes.

Predation and community structure

Stanley is most well known for his work on the role of size-selective predation in sha** zooplankton communities. The paper by Brooks and Dodson (1965) showed the clear effects of planktivorous fish in reducing the size of the dominant zooplankton. The flip side of the question was less clear; why are zooplankton communities in the absence of fish dominated by larger zooplankton? Brooks and Dodson proposed the size efficiency hypothesis: larger zooplankton are more efficient and hence out-compete the smaller zooplankton.

Stanley’s own graduate research tested this idea (Dodson, 1970) and later experiments favored an alternative hypothesis: larger zooplankton include invertebrate predators that are themselves size selective (capture smaller zooplankton) (Dodson, 1974a). The later explosion of research on both competition and predation in sha** zooplankton communities has generally supported this hypothesis (Kerfoot, 1987) and also led to exploring similar ideas in streams (Peckarsky & Dodson, 1980). The importance of predators was also extended to another important problem, related to the nature of polymorphisms within individual zooplankton species.

Cyclomorphosis and the role of predator-induced polymorphisms

The phenomenon of cyclomorphosis has been a puzzle for well over a century (Hutchinson, 1967) and was addressed by Stanley in an interesting idea paper, which proposed that helmets and spines in zooplankton are morphological adaptations to thwart invertebrate predators while not making them more vulnerable to fish (Dodson, 1974b). A key to this puzzle followed early work by Gilbert (1966), which showed that some zooplankton predators release chemicals into the water (kairomones) that induce changes in morphology of rotifers, and these effects in turn provide a protective benefit. Stanley extended this research to Daphnia (Krueger & Dodson, 1981) and numerous studies confirmed this mechanism as a general one (reviewed in Dodson, 1989). A related issue involved the proximal causes of diel vertical migration. Zooplankton migrate over large vertical distances in lakes (many thousands of body lengths per day) and we now know that the main adaptive significance is a reduction of predation by sight-feeding predators (Lampert, 1989). The proximate cue is strongly linked to light, but is modified by the presence of predators. In a simple laboratory experiment, Dodson (1990) showed that fish kairomones amplified the vertical migration behavior of zooplankton, and this work has been confirmed by numerous larger-scale studies (De Meester, 2009).

Factors influencing species richness in lakes

Stanley was an excellent taxonomist and became interested in the factors that are related to biodiversity in lakes. He focused on the pelagic zooplankton and first looked at the relation between richness and area over a broad size range of water bodies (Dodson, 1992). A later collaboration revealed that after area effects are factored out, zooplankton diversity is strongly influenced by productivity, being maximal at intermediate values (Dodson et al., 2000a, b). Thus, productivity not only has numerous effects on lake structure and function (Wetzel, 2001), but also effects on plankton communities. Indeed, in an earlier paper on feeding mechanisms of cladocerans and copepods, Richman & Dodson (1983) proposed that their relative dominance should follow trophic gradients. Further work revealed additional effects of lake age on species richness (Dodson et al., 2007).

Stanley understood that, although species richness was related to lake size, age, and productivity, the relationship between any of these factors and biological communities was mediated by watershed land-use. He studied lakes in pristine (Dodson et al., 2009), agricultural (Dodson et al., 2005), and suburban (Dodson, 2008) settings to illustrate that watershed land-use is overwhelmingly important in structuring aquatic communities in an increasingly human-dominated landscape. After years of viewing agriculture as the major driver of declines in species richness in small ponds, he was greatly surprised to discover that agriculture had negligible effects on community structure. Instead, the amount of manicured lawn surrounding a pond affected the richness and composition of nearly every group of organisms (Dodson, 2008).

Impacts of contaminants on water quality in lakes

Although much of Stanley Dodson’s research focused on basic ecology, he became increasingly interested in environmental contamination in lake communities. An early graduate student, Theo Colborn, convinced him that chemicals have far-reaching effects. Stanley supervised a series of graduate students working on environmental toxicology and their publications indicated effects at both population and community levels (e.g., Kashian & Dodson, 2002, Dodson et al., 2005). Much work was also done to shed light on the interaction of anthropogenic and natural chemicals, and their effects on the invertebrate community (Dodson & Hanazato, 1995). Further studies revealed the effects of land use and human-produced chemicals on biodiversity in ponds and shallow lakes (Dodson et al., 2005, 2007). Following the idea that endocrine disruptors are common and have wide-reaching effects in the environment (Colborn et al., 1997), Stanley and his students discovered that Daphnia sex ratios are disrupted by environmental contamination and developed a patent for the experimental method (Dodson et al., 1999; Fig. 3).

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Stanley with former student Theo Colborn, who helped ignite his interest in environmental contaminants

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Systematics of cladocerans and copepods

Stanley Dodson was also well known by cladoceran and copepod taxonomists for his careful and imaginative work on both groups. He and his students described new species and genera of cladocerans (Daphnia brooksi, Dodson, 1985; Dumontia oregonensis, Santos-Flores & Dodson, 2003). In Stanley’s honor, two new species of copepods have been named after him (Elias-Gutierrez et al., 1999, Mercado et al., 2006).

Stanley helped sort out problematic groups of both cladocerans (Dodson, 1981) and copepods (Dodson, 1994, Dodson et al., 2003), and at the time of his death had completed major reanalyses of two copepod genera (Diaptomus: Dodson et al., in prep; and Eurytemora: Dodson, Skelly, and Lee., in review). Stanley always strove to “get things right,” to be objective, comprehensive, and systematic. He delved into a variety of multivariate and phylogenetic analyses in order to identify morphological characters that were diagnostic for each group. Stanley’s philosophy on this topic was conveyed in his opinion paper “Recommendations for taxonomic submissions to Hydrobiologia” (Dodson & Lee, 2006).

His knowledge of the ecology and systematics of cladocerans made Stanley the natural choice for summary reviews on the group. Working initially with David Frey, Stanley wrote the chapter on cladocerans and other branchiopods for the edited volumes by Thorp and Covich (Dodson & Frey, 1991, 2001). The third edition is currently in press (Dodson et al., 2009).

Conclusion

Stanley Dodson had a major influence on more than one generation of aquatic ecologists. His work was creative and addressed some of the major questions that continue to fascinate us. Stanley helped transform the way we think about how lakes function and about how their inhabitants interact and evolve. He loved what he did and enjoyed sharing his insights with others. The limnology community has lost an imaginative scientist and a loyal friend.