Newsletter - February 1995
International Center for Tropical Ecology at the University of Missouri - St. Louis
by Zuleyma Tang-Martinez, Biology Department, University of Missouri - St. Louis
Public and scientific awareness of the threat to the world's biological diversity has made conservation biology one of the most important and relevant fields in the biological sciences. Ecology, evolution, systematics, and population genetics are all recognized as important components of conservation biology. Animal behavior, on the other hand, has received little attention as a field that can contribute significantly to conservation efforts. Nonetheless, animal behavior not only can contribute to conservation, but should play a vital role as a component of conservation biology.
The field of animal behavior encompasses the study of: a) the physiological and sensory mechanisms that control behavior; b) the development or ontogeny of behavior; and c) the function and evolution ofbehavior. A knowledge of all three of these areas of animal behavior cancontribute to efforts to save endangered species through captive breeding programs or by managing endangered populations in their natural habitats.
Captive Breeding Programs
A major problem faced by captive breeding programs is reproductive failure or insufficiency. In many cases environmental, physiological, and social conditions necessary for successful reproduction of endangered species are not known. The role that a knowledge of animal behavior can play in these situations is illustrated by the work of Devra Kleiman, former President of the Animal Behavior Society and 1988 recipient of the Distinguished Achievement Award of the Society for Conservation Biology. Kleiman, working at the National Zoo, in Washington, D.C., has conducted behavioral research on the mechanisms of pair formation, on physiological and social factors necessary for reproduction, and on patterns of parentalc are in the endangered golden lion tamarin (Leontopithecus rosalia).This research has led to the successful reintroduction of this species into its natural habitat in Brazil. Her reintroduction program, informed by herbehavioral research, has had a major impact both on the numbers of tamarins surviving in the wild and on the amount of protected habitat available to the species (some of the introductions occurred on private lands now under protection).
Another problem that arises when endangered species are bred in captivity and released in the wild is that the animals may never have developed appropriate mate choice mechanisms, intraspecific signaling systems, or the ability to recognize natural predators. For example, animals raised by humans may not be able to recognize members of their own species as appropriate sexual partners. Studies by animal behavioristshave shown that "sexual imprinting", a mechanism by which animals learn to recognize an appropriate mate, is widespread among birds and that, once established early in life, it is essentially irreversible. An understanding of sexual imprinting has played a critical role in the SanDiego Zoo's project to breed the nearly extinct California condor (Gymnogyps californianus) in an attempt to return it to the wild. Young condors hatched in captivity are not allowed to see humans. Instead, all care and feeding of chicks is done with a hand puppet of an adult California condor, thus preventing imprinting on humans and facilitating sexual imprinting on other condors.
Other studies have demonstrated that in some monkey and ape species even social signals must be learned from conspecifics. In such species, individuals raised by humans may not develop the communication skills to survive and do well when they are reintroduced into their natural habitat. Similarly, work by Sue Mineka, at the University of Wisconsin, has shownthat some species of monkeys (e.g., rhesus macaques and some tamarins) must learn to recognize and avoid their natural predators. An understanding of behavioral developmental mechanisms and the teaching of behavioral survival skills should, therefore, be integral components of any reintroduction program.
Endangered Species in Their Natural Habitat
An understanding of physiological and sensory mechanisms in behavior can be critical in attempts to conserve end angered species in their natural habitats. For example, Charles Snowdon (also a former President of the Animal Behavior Society) and his colleagues at the University of Wisconsinhave developed non-invasive and non-disruptive hormonal assays (using urine collected in the field) to monitor ovulation and pregnancy in mountain gorillas (Gorilla gorilla berengei). The same techniques are used to determine changes with age in the levels of testosterone of male gorillas. Data on reproductive hormones levels and their behavioral correlates in wild populations of the mountain gorilla can provide information of great value in designing effective conservation strategies.
Knowledge of the sensory mechanisms of behavior are also important. Studies have shown that salmon, as well as some other fish species, use chemoreception to orient to their home streams for reproduction. The pollution of streams with pulp mill affluents, heavy metals, or oil spills can have drastic consequences on fish populations because the fish become disoriented, unable to find their home streams, and unable to reproduce. Likewise, many species of sea turtles hatch at night on oceanic beaches and then orient towards the ocean using light cues, such as the brightness ofthe water. Photopollution from cities and beach lights has been shown to disorient the turtles, making them more susceptible to predation and dehydration. Since many species of sea turtles are endangered, an awareness of the sensory mechanisms responsible for orientation may help us to manage photopollution in ways that will increase the survival probability of turtle hatchlings.
The importance of animal behavior in the management of natural populations is particularly evident when one considers some of the factors that can influence effective population size (Ne), a critical parameter in conservation biology. By influencing the effective population size, these factors also affect the genetic structure of populations andthe amount of genetic variability. Dominance relationships and social systems in which territories are necessary for breeding can result in populations in which not all individuals breed, thus reducing Ne. In extreme cases, reproductive suppression by dominance interactions can lead to situations in which only a small percentage of the animals in the population actually contribute the gametes that will give rise to the next generation. Mating systems, by affecting the number of individuals that actually breed in a population, also affect Ne. For example, extreme polygyny, in which only a small number of the available males breed with the all the available females, will reduce genetic variability and change Ne. Lastly, nesting behavior and nest preferences can affect the effective population size if nests are limited and individuals nestsingly, so that only some individuals are able to breed. On the other hand, in species that nest communally (several pairs per nest), the effects of nest "limitation" is likely to be much less important. Thus, knowledge of the social structure, social behavior, mating systems, and nesting behavior of species is critical if we are to accurately estimate effective population size and genetic variability of populations.
Another factor that influences genetic structure of populations is dispersal, a major area of study for behavioral ecologists. Species in which philopatry is the rule are expected to be more inbred than species inwhich there are high levels of dispersal. Knowing whether under normal conditions a population consists of philopatric individuals, and therefore shows less genetic variability than if dispersal were the norm, is of critical importance in management efforts that include the introduction of new, genetically different genetic diversity. Patricia Parker from Ohio State University has argued that in some cases such introductions may be counterproductive because low genetic variability may be normal for certain healthy populations. She cites two populations of stripe-backed wrens (Campylorhyncus nuchallis) from Venezuela. One population, which is healthy and growing, shows limited dispersal and low genetic diversity. A second population, which is declining and extremely unstable, has a high rate of immigrants and relatively high genetic diversity. Thus, low geneticdiversity may not always be detrimental and high genetic diversity may, insome cases, be associated with negative population effects. Therefore, aknowledge of normal dispersal patterns (both emigration and immigration) and normal genetic variation should be considered before attempts are made to artificially increase genetic diversity in populations.
The examples discussed above illustrate only some of the many behavioral processes that can be significant in conservation biology. Other topics include foraging behaviors and food preferences, habitat selection, the use of behaviors (e.g., bird songs) for more accurate censusing, the effects of social structure on disease epidemiology, and theuse of animal behavior as an early warning system for environmental changesand pollution.
by Cynthia Radding, Department of History, University of Missouri - St. Louis
Ethnohistory and ecology comprise two closely relatedinter disciplinary fields that hold great promise for comparative research. Environmental issues have set in motion new currents in Latin American historiography, arising from the fertile meeting ground of history, anthropology and geography. Ethnohistorians have paid fruitful attention to the ecological component of pre-Hispanic agricultural systems and societies; scholars who focus on environmental, social, and economic history have expanded our working definition of environment and landscape to emphasize their processual quality as changing entities inconstant interplay with the different groups of social actors that inhabit them.
My work compares two frontiers of the Ibero-American world created by the Conquest, one each from the arid and subtropical areas of the Americasthat were relatively sparsely populated and only gradually brought under European domination. The first of these is Northwest Mexico, whose defining geographic feature is the Sonoran Desert; the second is Eastern Bolivia, characterized by tropical rainforests and savannas. The ecological processes of these frontier regions developed according to historical rhythms of change that distinguished them from the core areas of the Hispanic viceroyalties and illustrated their migratory social patterns. The initiatives and responses of both the Amerindian and European peoples thatsettled these areas set in motion processes of long-term environmentalchange.
My research emphasizes the ecological significance of Indian labor and productivity. It concerns the cultural values ascribed to both productive and ceremonial labor and the distribution of the material products of work, whether for colonial surplus or for indigenous subsistence. These cultural and technological factors at times have allowed for innovation andadaptation and, at other times, constrained human adjustments toenvironmental change. I have forged the term "social ecology" to express the relationship between different human communities and the environment inwhich they live together with the intricate social and political relationsthat developed historically among conquered and conquerors, Indians and Europeans, peasants and landlords.
The high land peoples of Sonora (Mexico) in the western foothills of the Sierra Madre Occidental depended on the combined resources derived from cultivation, hunting and foraging. They had developed a variety of techniques for growing cultigens in open fields and garden plots. Experienced horticulturalists, their knowledge of plant selection, soil conservation, and water management enabled them to produce sufficient food for themselves in this arid environment. The colonial regime implanted in this province in the seventeenth century through the Jesuit mission systemaltered the Sonorans' ecological and social relations in a number of important ways. First, although the missions conserved a nucleus of communal lands and allowed the Indians to continue their farming methods, Jesuit administration channeled native productive energy away from household subsistence to agricultural surpluses to be sold to mining camps and presidios or otherwise distributed throughout the Jesuit missionsystem. Secondly, the Spanish economy encroached spatially and organizationally on native communities. Indian labor was drawn into the orbit of mining and ranching through the network of local and regional markets that developed around the reales de minas of Sonora and Nueva Vizcaya. And thirdly, as the eighteenth century advanced, control over landand the precious resources of water and natural pasturage shifted from Indian communities to private haciendas and ranchos. Nearly a century before land itself became the object of dispute, miners, missionaries, and native governors contended for control over Indian labor. The socialecology of the Sonoran peoples was intimately tied to the demographic and economic sustenance of their communities and, in turn, supported both their resource base and their cultural definition of ethnic identity. The military defeat of Sonoran ethnic polities by mid-nineteenth century and their absorption into the Mexican economy constituted a significant turningpoint in the global process that had altered (and, in many ways impoverished) their environment and shifted their mode of subsistence from village horticulture to dependent labor and sharecropping.
The colonial history of the Province of Chiquitos in eastern Boliviashared several points in common with that of Sonora, not withstanding thegreat distance and geographic contrasts between both regions. Spanish explorers first invaded the area proceeding northwest from Asunciï¿½n deParaguay. During the sixteenth and early seventeenth centuries, the many different tribal groups of this area were subjected periodically to forced labor. Nevertheless, as in Sonora, Spanish dominion was not secured in Chiquitos until Jesuit missions were established there, with the consent ofnative leaders, to protect their people from Spanish and Portuguese enslavement. As in Sonora, the missions of Chiquitos served to harness the labor of semi-nomadic agriculturalists and gatherers to supply the mining economy with essential goods and support internal networks of commercial exchange. While the Sonoran missions produced food surpluses, principally maize, wheat, and cattle, for sale in the northern Mexican mines, the Chiquitos missions sent regular shipments of wax and cotton cloth to the mines at Potosï¿½ (Upper Peru). Subsistence food production apparently continued under the norms of native swidden practices, but land use patterns were significantly altered by the introduction of beef cattle: the missions maintained substantial herds in order to keep their neophytes supplied with meat, a necessary quid pro quo for the labor demanded of them. Undeniably the colonial regime redirected a significant proportion of indigenous productive energy to supporting the mining economy and forced the resettlement of many different ethnic peoples in mission compounds, altering longstanding migratory patterns and changing the ecological andeconomic relations that bound these ethnic communities to each other and to the soil.
The counterpart to conquest and colonial domination is, of course, native resistance. This historical dialectic infused both the rhythm and content of European expansion in the Americas; and the study of its environmental, social, and cultural consequences is especially fruitful inthe frontier zones of the empire. It is clear that migratory patterns and cultural resistance conditioned the geographic extension and the political control exercised by Iberian colonialism. The Indians' physical mobility, enhanced in part by the very rigors of their natural environments, gave these frontier peoples a certain leverage in dealing with the Spaniards.The ecological dimension of their historical experience is necessarilyen twined with the social, political, and economic processes of colonial domination and with the many shades of accommodation and resistance that color the Amerindian responses to Iberian conquest.
The Center for International Studies and the U.M. Research Board have generously funded portions of my project. This kind of comparative research has born fruit in a cross-disciplinary graduate seminar currently under way at U.M.-St. Louis entitled: "Historical Perspectives on Ecology and Peasant Economy in Latin America." Offered through the Biology and History Departments and under the auspices of the International Center for Tropical Ecology, the seminar brings together students from history, biology, political science, and business. The seminar is truly international, with participants from Mexico, Peru, Colombia, and Venezuela as well as North Americans of different backgrounds. Our discussions bring together the social and biological dimensions of ecology and illustrate complementary research perspectives. Editor's note: The drawing and quote are from Gathering the Desert, by G. Nabhan.
by Aimee Campbell, Anthropology Department, Washington University
and Elizabeth Wentz, Department of Geography, The Pennsylvania State University
The global environmental crisis has focused public attention on theonce-esoteric subject of rain forest conservation. Tropical rain forest ecosystems are among the most complex on earth and conservation in the tropics begins with fundamental knowledge of what there is to conserve. Primates are an important component of tropical ecosystems and have long fascinated anthropologists, biologists, and zoologists. Here we describean innovative use of a geographic information system (ARC/INFO, GISsoftware designed by ESRI) in a 16-month comparative ecological field study of two primate species in a Costa Rican rain forest. We believe this is the first use of GIS in primate field research. This project combines basic research on primate feeding and ranging with GIS methods to better understand resource and habitat requirements necessary to protect and sustain primate populations.
La Selva Biological Station
The study described here was carried out at the La Selva Biological Station, Costa Rica. La Selva consists of 1500 hectares (3750 acres), of which about 64% is primary rain forest. The remainder is a mosaic of secondary forest, abandoned pastures and plantations and managed habitats. The physical plant is extensive, and provides housing and services for up to 70 people per night. Recent explosive growth in station use, coupled with increased sophistication of the laboratories, created a research environment ready to use GIS for spatial planning and analysis.
The GIS at La Selva started in 1989 with a detailed design study that included interviews with over twenty La Selva representatives to assess the spatial analysis needs of administrators and researchers. The equipment and software were obtained in 1991. The installation, including hardware setup, database building, and training a permanent database manager, was completed in 1992. The installation phase included building ageographically referenced database. Publicly available maps did not provide sufficient detail for researchers at La Selva. As a result, a topographic survey of the site was professionaly contracted and a 50 by 100 meter grid was installed throughout the forest. The grid facilitates field mapping and off-trail navigation and provides a detailed topographic map of the station. The survey also included streams, trails and other features, and forms the framework for the rest of the permanent geographical database. In addition, aerial photographs and satellite data are being obtained to broaden the possibilities for spatial analysis. Access to suchdetailed geographical data is extremely rare at a rain forest station. Researchers at La Selva have a unique opportunity to perform on-sitespatial analysis with sophisticated hardware and software, in an environment which fosters data integration between researchers in varied disciplines.
The first scientific use of the system was Project MONOS (under the direction of the first author), a 16-month comparative ecological study of two of the primate species that coexist at La Selva: Ateles geoffroyi(red spider monkey) and Cebus capucinus (white faced capuchin). A major component of the study included a comparative look at the feeding patterns of the primates. Both primates are highly frugivorous, that is, they depend on ripe fruit throughout the year. Key issues were to determine how differences in fruit resource abundance and distribution affect feeding and ranging behavior and how differences in feeding and ranging affect patterns of social organization. Research methods included behavioral data collection and data collection on spatial and temporal distribution of fruit resources used by the monkeys. Monkeys were followed four days per week. Time sampling techniques were used to collect quantitative data on feeding behavior, ranging patterns, and social grouping.
In this report we focus on the application of GIS to understanding the distribution in space and time of fruit resources used by the two primates. All trees in which the monkeys ate fruit were marked with forestry flagging at the time of observation. These trees were later mapped to the surveyed grid. Prior to the installation of the GIS, each tree was plotted by hand on a paper map of the study site. With paper maps, it is difficult to incorporate attribute data, perform attribute queries and other spatial analyses, and make corrections. After the installation of the GIS at La Selva, all mapped fruit-feeding trees used by both primate species were entered as point data into the project database. Associated attribute data (tree species, date eaten, etc.) were also entered to produce the feeding tree database (N=868 trees). The digital database can be easily checked and edited and is fully portable for analysis and manipulation at any ARC/INFO site.
Primate Field Research: New Applications for ARC/INFO
The possibilities for GIS use in primate field research are vast and virtually untapped. Some of the topics that we are using ARC/INFO to explore include:
Understanding how the animals use forest space:
(1) To calculate overall home range - We are experimenting with a variety of techniques, such as counting the number of one hectare (and smaller) grid squares that contain feeding trees, measuring the area of the minimum convex polygon containing all feeding trees, and calculating the area enclosed by buffers of various sizes around each feeding tree; (2) To understand daily use of space - GIS tools are used to measure daily path length and daily home range size of the primates. This is critical in understanding how seasonal variation of food resources affects their use of the forest; and (3) To obtain a better understanding of primate habitat - Overlay analyses of preferred feeding tree data with soils, topography, and hydrology will yield better understanding of habitat requirements of the animals. Home range area is only one habitat component; tree species density, diversity, and distribution all impact primate habitat as well.
Understanding feeding tree selection:
(1) To examine the spatial distribution of preferred fruit speciesused by each primate - Fruit resources vary in patterns of spatial and temporal availability. Understanding the spatial component is an important aspect of foraging behavior; (2) To examine the distribution of infrequently-used trees - Some of the trees used by the monkeys were used frequently, while others were only used once or rarely. Rare trees used enroute from one preferred resource to another indicate incidental use, while rare trees visited independently indicate selection or preference. Such trees may constitute a small fraction of the overall diet, but may be critically importnat for brief periods during the year; (3) To examine variability in spatial patterning of resources - The density and clustering of trees varies throughout the home range. Using GIS, the regions with unique clustering patterns can be identified and further investigation of these areas may provide insight into why they were important feeding resources; and (4) To investigate the impact of using radio tracking on data collection.
Observation conditions at La Selva are poor due to dense vegetation, hilly terrain, and heavy rainfall. Radio tracking was therefore used to assist in finding and following the animals, beginning in the fifth month of the study. Buffer analyses of trails showed that before using radio tracking most feeding trees marked were within 50 meters of a trail. After using radio tracking, marked feeding trees were widely distributed, which resulted from our improved ability to find and follow the animals.
Future primate field studies at La Selva will include GIS in the initial research design and expand on results obtained in the currentstudy. A potential project to study and compare frugivorous birds and primates in the forest canopy at La Selva will use GIS to analyze ranging patterns of animals, seed and seedling dispersal, and spatio-temporal distribution of resources. These types of studies represent some of the most basic themes for using GIS in tropical ecology. Combining GIS, basic ecological research, and conservation biology can have broad and far-reaching consequences. Our work has only begun to exploit the analytical possibilities of this interdisciplinary union.
Editor's Note: This article originally was published by ESRI in ARC/NEWS. ESRI makes ARC/INFO software and has an office in St. Charles.
Luis Miguel Renjifo, a Ph.D. candidate in the Department ofBiology became the first Parker-Gentry Fellow (see article in previousnewsletter). Receipt of the Parker-Gentry Tropical Research Fellowshipwill enable Luis Miguel to study the conservation of montane forest birdsin the Colombian Andes. Colombia contains over 1700 species of birds, morethan 18% of all the birds of the world. The Andes support a particularlyrich avifauna, including many birds found nowhere else in the world. Yet,these spectacular montane forests have been heavily affected by humanactivities, creating a crisis situation for the continued conservation ofAndean plant and animal species. The dissertation research of Luis MiguelRenjifo, a Colombian native, will directly assist ongoing conservationefforts in this biologically important region. During the course of hisstudies, he will work closely with ICTE scientists and conservationistsfrom Wildlife Conservation Society and Fundacion Herencia Verde, a majorColombian NGO active in environmental education and conservation planningin the region.
This prestigious fellowship was established through the generosity ofan anonymous donor to honor the memory of two of the world's most prominenttropical biologists, Theodore A. Parker III and Alwyn H. Gentry, who werekilled in a tragic plane accident on August 3, 1993 while on a ConservationInternational Rapid Assessment Program visit in Ecuador. Tax-deductiblecontributions to The Parker-Gentry Fellowship Fund can be sent to theInternational Center for Tropical Ecology, UM-St. Louis, 8001 NaturalBridge Road, St. Louis, MO, 63121.
TROPICAL ECOLOGY GALA
Thanks to the efforts of The Friends of UM-St. Louis and theInternational Center for Tropical Ecology the Tropical Ecology Gala,held Thursday, January 12, 1995, was a great success. The evening, whichfeatured the presentation of the Chancellor's Medallion to Dr. Peter Raven,raised $25,000 to support graduate student research in the tropics. As aconsequence, the ICTE will be able to fund many more excellent research projects.
The International Center for Tropical Ecology is pleased to announce that Mercedes Rougï¿½s, a Ph.D. student from Argentina, has beenselected from an outstanding field of applicants as the 1995 recipient ofthe Stephen Mitchell Doyle Scholarship in Tropical Ecology. Thisscholarship will enable Mercedes to attend the Neotropical OrnithologicalCongress (V Congreso de Ornitologia Neotropical) to be held in Asunciï¿½n,Paraguay, from 5 to 11 August. This congress, held every four years, isthe most important ornithological meeting in Latin America and is attendedby scientists and students from throughout North and South America.Mercedes plans to conduct her Ph.D. research on bird communities of montaneforests found in northwestern Argentina; this meeting will allow her topresent her preliminary data and provide an opportunity to discuss herresearch plans with scientists from throughout Latin America.
The Doyle Scholarship, awarded to an outstanding graduate studentinterested in tropical biology who has initiated research in the areas ofecology, evolution, systematics, or conservation biology, was establishedas an ongoing endowment to support the training and research of graduatestudents in master's and doctoral programs at the International Center forTropical Ecology. A major goal of the ICTE is to promote the search for solutions to environmental problems that stem from loss andalteration of tropical forests and other habitats. Such solutions will befound, at least partially, in research done by students at UM-St. Louis.Thus, the scholarship is awarded to help fund original research or to fundtravel to national and international meetings. Presentation of researchresults at such meetings ensures that the findings become known to a wideraudience. Past recipients of the Doyle Scholarship have traveled to Panamaand Peru to conduct research and to Vienna to participate in aninternational congress.
The Scholarship Fund is a fitting tribute to Stephen, who - as ascientist, gardener, nature lover, and professional in the field of healthcare - was dedicated to conservation and to the expansion of biologicalknowledge and its application. Contributing to the Fund will ensure apermanent endowment that will serve both as an ongoing source of supportfor the study of tropical ecology and as a lasting memorial to Stephen.All contributions to the Fund are tax deductible and can be sent to TheStephen Mitchell Doyle Scholarship Fund in Tropical Ecology, InternationalCenter for Tropical Ecology, University of Missouri-St. Louis, 8001 NaturalBridge Road, St. Louis, MO 63121.
Dr. Lincoln P. Brower, University of Florida, will present the 1995 Jane and Whitney Harris Lecture, entitled The Grand Saga of the Monarch Butterfly. This public lecture describes the remarkable annual migrationof these butterflies to their overwintering sites in boreal forests ofMexico. The lecture, richly illustrated with color slides, will concludewith a discussion of why the migration has become "an endangered biologicalphenomenon". The talk will be presented on 15 March 1995, 7:30 PM, in theSchoenberg Auditorium of the Missouri Botanical Garden. Dr. Peter Raven, Director of the Garden, will introduce Dr. Brower. A reception will followthe lecture. For additional information call 516-5442.