AMER. ZOOL., 34:48-56 (1994) Systematics and Natural History, Foundations for Understanding and Conserving Biodiversity1 HARRY W. GREENE Museum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley, California 94720 SYNOPSIS. Enhanced by recent technical and conceptual advances, two classical endeavors in biology play vital roles in understanding, appre- ciating, and managing biodiversity. Systematics defines the fundamental Downloaded from https://academic.oup.com/icb/article/34/1/48/111738 by guest on 30 September 2021 units and relationships among living things; natural history chronicles the lifestyles of organisms in relation to environments. For example, analyses of evolutionary relationships emphasize the uniqueness of certain taxa, help prioritize groups of organisms for conservation, and enable us to estimate the biology of unstudied taxa. Radiotelemetry permits repeated location of snakes and other stealthy animals, facilitating previously impossible behavioral studies and thus laying the groundwork for effective management. Natural history in a systematic and geographic context pro- vides a "rule-of-thumb" for predicting extinction due to global climate change. Educators should emphasize the urgency of the biodiversity crisis, inform debates about priorities for funding and other conservation mat- ters, and teach about the goals, methods, and applications of systematics and natural history. INTRODUCTION UNDERSTANDING AND APPRECIATING An environmental crisis is upon us, not BIODIVERSITY just looming on the horizon. More than six What are systematics and natural history? billion humans will burden the earth by the Systematics encompasses the character- end of the 20th Century, regardless of our istics, genetic status, and evolutionary his- best efforts, and extinction of many plant tories of organisms. Once devoted mainly and animal species is underway now. In to describing obvious phenotypic variation addition to ameliorating the harmful effects and coining formal names, systematists now of population growth and pollution, we must evaluate samples from throughout the geo- rapidly influence public opinion and save graphic distribution of living things with portions of the remaining biotas (Wilson, morphological, biochemical, multivariate 1992). Here I briefly review the broad goals statistical, and other sophisticated tech- and methods of modern systematics and niques. Phylogenetic systematics, in partic- natural history, then illustrate how these ular, strives to infer the evolutionary his- activities contribute to our understanding, tories of independent lineages (species and appreciation, and conservation of biodiver- higher taxa), and to determine relationships sity. I focus on the applications of phylo- between geography and the divergence of genetic analysis and on telemetry studies of organisms (Cracraft, 1994; O'Hara, 1994). stealthy vertebrates, illustrating how new techniques enhance traditional approaches. Natural history focuses on where organ- isms are and what they do in their environ- ments, including interactions with each other. The building blocks of natural history are descriptive ecology and ethology- detailed accounts of organismal biology in 1 From the symposium Science as a Way of Know- ing—Biodiversity presented at the Annual Meeting of natural settings—followed by experimental the American Society of Zoologists, 27-30 December studies of factors that affect distribution, 1992, at Vancouver, Canada. abundance, and interactions. 48 BASIC BIOLOGY AND BIODIVERSITY 49 Conserving and appreciating nature The uncertain but potentially serious con- Systematics and natural history define the sequences of rapid climate change are a new boundaries and contours of biodiversity; challenge for conservation in the coming they elucidate the fundamental kinds of decades. Ideally, the predicted impact of organisms (species and higher taxa) as well temperature and moisture shifts (via organ- as their interactions with each other and ismal physiology) on population viability their environments. Areas are chosen for will be incorporated into management strat- conservation based on, among other crite- egies (Kareiva et al., 1992). Such detailed ria, the kinds and numbers of organisms knowledge requires years of research and is Downloaded from https://academic.oup.com/icb/article/34/1/48/111738 by guest on 30 September 2021 they encompass; effective captive breeding available for relatively few species, so indi- and reintroduction depend on knowledge of rect methods are potentially useful. For example, McDonald and Brown (1992) used a species' ecology and behavior; and pop- presence or absence of montane mammals ular films and books translate research find- on isolated ranges of different sizes in the ings about nature into public education Great Basin to estimate minimum refuge (Greene and Losos, 1988). I will elaborate areas for each species. The resulting thresh- on two roles for systematics and natural his- olds for refuge area were then compared with tory, the first ubiquitous but widely unrec- estimates of habitat shrinkage from climate ognized and the other relatively new. change to predict future extinctions. That If wild organisms and places are to be technique is limited to fairly large samples conserved, they must have value in human of habitat islands with well-documented societies. Interactions among plants and biotas; a less precise but more broadly appli- animals hold countless solutions to natural cable "rule-of-thumb" approach based on problems with analogues in human welfare; systematics and natural history is illustrated the skin toxins of dart-poison frogs and other later in this paper: Terrestrial species with natural products with pharmaceutical appli- fragmented geographic ranges and narrow cations are well known examples (e.g., Wil- elevational tolerances are especially at risk son, 1992). Equally important in the long under changing regimes of temperature and run, systematics and natural history also moisture. underlie esthetic evaluation, cultural accep- tance, and prioritization for management. STUDYING STEALTHY VERTEBRATES Beyond intrinsic cuteness, we regard the giant panda as special because of its con- The information on ecology and behavior troversial relationships with bears and rac- necessary for conservation, management, coons, strange thumblike dewclaws, and diet and nature appreciation are available for of bamboo. In the economic and political only a tiny fraction of species, generally those arenas of conservation, efforts to save rain- that are large, common, or otherwise rela- forests are based on their demonstrably tively easy to study (Greene, 1986). incomparable biodiversity, not just the Advances in telemetry during the past two emotional responses some of us have to decades, however, have greatly enhanced those places. Striking resemblances of unre- research on stealthy and otherwise cryptic lated organisms from distant, similar hab- animals. Early workers mostly localized itats are a common theme in exhibit labels radio signal coordinates on a map, but and other forms of environmental educa- recently biologists have used telemetry to tion, yet without phylogenetic evidence that study undisturbed animals more directly in similar traits indeed were acquired inde- nature (e.g., Emmons, 1987, for rainforest pendently we could not marvel at conver- cats). Our research on pitvipers in Arizona gent evolution (Luke, 1986). Systematics and illustrates the use of miniaturized, surgically natural history even facilitate the transfer implanted transmitters (Reinert, 1992) to and evaluation of knowledge about nature facilitate repeated encounters and behav- among human societies, since ethnobiology ioral observations. is based on their results (e.g., Patton et al, Since 1986 my colleagues and I have fol- 1982). lowed 17 blacktailed rattlesnakes (Crotalus molossus) in the Chiricahua Mountains, for HARRY W. GREENE Downloaded from https://academic.oup.com/icb/article/34/1/48/111738 by guest on 30 September 2021 FIG. 1. Vignettes from the natural history of blacktailed rattlesnakes (Crotalus molossus) in the Chiricahua Mountains, Cochise Co., Arizona. Courtship behavior in a juniper tree, 24 August 1991; telemetered male's head (#8, total length ca. 1 m) is pressed against the smaller female's neck (photograph by D. L. Hardy, ST.). periods of a few days to more than four or by following previously telemetered indi- years. Despite bright colors and a total length viduals, and during ca. seven months of of ca. 1 m, these snakes are indeed cryptic fieldwork at the site I encountered only one and difficult to locate. Most of our study blacktail by visual scanning in the habitat. animals were found as they crossed a road With telemetry, we have documented pat- BASIC BIOLOGY AND BIODIVERSITY 51 Downloaded from https://academic.oup.com/icb/article/34/1/48/111738 by guest on 30 September 2021 FIG. 2. Vignettes from the natural history of blacktailed rattlesnakes (Crotalus molossus) in the Chiricahua Mountains, Cochise Co., Arizona. Telemetered male (#6, total length ca. 80 cm) basking on a woodrat (Neotoma) nest, 29 September 1990; a suspiciously rat-sized bulge is visible on the left side of the snake. In each case observations commenced when the male was located initially by radiotelemetry. terns of daily and seasonal movements, Two SMALL RATTLESNAKES: SYSTEMATICS, ambush hunting tactics, late autumn feed- NATURAL HISTORY, AND DIVERGENT ing, courtship,