Mammals

Costa Rica is one of the most biotically diverse countries on earth, with 4% of known terrestrial plant and animal species in only 0.04% of the world’s land surface. The country’s mammal fauna is equally diverse, with more than 207 species (4.8% of the world’s 4629 species) in an area of 51,022 km2. The majority of the world’s mammal species and Monteverde’s fauna are small (< 0.5 kg), nocturnal, and secretive. We know considerably less about most neotropical mammals and other vertebrates than we do about birds, which are more easily observed and communicate with sounds audible to humans. Although certain species of mammals have been studied in Costa Rica (Janzen 1983a, Timm 1994, Vaughan and Rodríguez 1994), and Monteverde is one of the best-known regions of the country biologically, there has been little work on the ecology, distribution, abundance, altitudinal zonation, systematic relationships, and biogeography of most mammals. Deforestation and other human disturbances have had a significant impact on the native mammals of the region; knowledge of Monteverde’s mammals is vital to understand how habitat changes affect tropical montane mammals. In this chapter, we provide an overview of the mammal fauna of the Monteverde area. We discuss the biology and abundance of some of the area’s species, document how these are changing, and explore conservation issues. Most of the research on mammals at Monteverde has centered on bats or rodents, the two most diverse groups. Much of our knowledge of other species consists of isolated observations. We augment published reports with unpublished observations made by ourselves and colleagues. We also examined most of the Monteverde mammal specimens in museum collections to verify species identifications and to understand better their systematics, ecology, and distribution. We integrate this information into a list of the mammals that occur in the region, document their occurrence in each life zone, and estimate their overall abundance.

The Physical Environment

Because biological diversity is directly related to diversity of the physical environment, a clear picture of the physical setting of the Cordillera is crucial to understand its ecology and conservation. The physical setting of Monteverde and the Cordillera de Tilarán encompasses a wide range of environmental conditions. The size, position across the trade windflow, geology, erosional dissection, and hydrology of the Cordillera interact to produce extraordinary physical diversity that parallels its great biological diversity. A major difference between tropical montane and lowland regions is the way biological diversity is distributed across the landscape. Montane regions are usually less diverse at the scale of 0.01-0.1 km2 but are as rich in species as nearby lowland areas at scales of 10-100 km2. We have two goals in this chapter. First, we review what is known of the climate and weather, geology and geologic history, geomorphology, soils, and hydrology of Monteverde. Our account focuses on higher elevations in Monteverde and wetter areas on the Caribbean slope, with less attention to the drier environments on the lower Pacific slope. Second, we point out areas where our knowledge is incomplete and suggest promising lines of future research. Although the geology and geomorphology of Monteverde are moderately well known, our knowledge of the rates of many geomorphic processes, particularly erosion, is poor. We also lack information on soils and hydrology, particularly of wind-driven cloud and precipitation inputs, evapotranspiration, and stream outputs from forests and other land-use types in Monteverde. Quantitative information on how variability in the physical environment interacts with biotic processes at the population, community, and ecosystem levels is scant. Most of the climate and weather data were collected at 1450 m at the Pensiόn (1956-1971), at 1520 m at John Campbell's residence (1972 to present), and intermittently throughout or near the Monteverde Cloud Forest Preserve (MCFP; Lawton and Dryer 1980, Crump et al. 1992, Clark 1994, Bohlman et al. 1995, W. Calvert and A. Nelson, unpubl. data).

Conservation Biology

Each February, when I return to Monteverde to study the reproductive ecology of lauraceous trees, I stay with friends in their farmhouse tucked on the edge of the lower montane moist forest. On my first morning back, I am always eager to listen to the dawn bird chorus. During my most recent visit, I awoke to hear a cacophony of Great-tailed Crackles, a noisy flock of Brown Jays, an exuberant House Wren, and a gang of Bronzed Cowbirds squabbling over spilled grain by the cow barn. Back in 1978, during my first visit, there were no Great-tailed Crackles in Monteverde. Brown Jays had colonized the area, but their flocks were relatively small and restricted to the lower parts of the community. House Wrens, always familiar denizens of Monteverde’s yards and farms, are more abundant today than ever. Once a rarity in Monteverde, Bronzed Cowbirds are now common. Monteverde has changed, and more changes are coming. The rest of Monteverde’s avifauna has undoubtedly felt an impact from the explosive population growth of these bird species. Crackles and jays prey on the eggs, nestlings, and fledglings of other birds; wrens also occasionally destroy other birds’ eggs. Cowbirds are brood parasites. All four species potentially compete with other species for food. Without censuses from earlier years, it is impossible to know how newly colonizing species have affected the fauna and flora of Monteverde. Contributors to this book have provided evidence that various species of animals and plants, especially widespread species of Costa Rica’s lowlands and foothills, have expanded their ranges and increased their population sizes in Monteverde. At the same time, other species are rarer than they used to be only a few decades ago. I used to marvel at the frenzied breeding aggregations of Golden Toads, hold multicolored Harlequin Frogs, and listen to nightly serenades of glass frogs along the Río Guacimal. Most of them no longer exist in Monteverde. In this chapter my goals are to (1) highlight aspects of the biodiversity of Monteverde that are relevant to conservation, (2) give a brief overview of general concepts in conservation biology, (3) discuss conservation problems that are specific to Monteverde and neotropical highland forests, and (4) consider how principles of conservation biology might provide solutions to those problems.

Conservation in the Monteverde Zone: Contributions of Conservation Organizations

Monteverde is renowned among tropical biologists, conservationists, and ecotourists for its cloud forests, quetzals, and Golden Toads. These forest ecosystems have been preserved while many other rain forests in Latin America have been destroyed for agriculture, wood products, and development. Initially, the area was preserved because it was nearly inaccessible; it remains protected because of dedicated efforts by local inhabitants, the development of effective grassroots organizations, and funds and expertise from the international scientific and conservation communities. In this chapter I document the development and contributions of grassroots conservation organizations that promote conservation practices and thinking. Four organizations preserved forested areas that now constitute the Monteverde Reserve Complex (see Fig. 1.7): (a) Bosqueterno, a reserve and organization formed by the Quaker settlers to protect their watershed; (b) the Monteverde Cloud Forest Preserve (MCFP) managed by the San José-based Tropical Science Center (TSC); (c) Bosque Eterno de los Niños (Children’s Eternal Forest; BEN), whose land was acquired by the Monteverde Conservation League (MCL); and (d) the Santa Elena High School Cloud Forest Reserve (SER) established by the local high school (colegio). Other activities discussed in this chapter are efforts to (1) protect reserve areas, (2) protect forest fragments outside the reserves and create corridors to link forested areas, (3) reforest and rehabilitate damaged land, (4) develop environmental education at all levels, (5) develop complementarity and cooperation among organizations, and (6) establish projects in sustainable development. These topics are linked with the growth of scientific knowledge and the development of ecotourism in the zone. The thesis of this chapter is that conservation organizations emerged as a series of responses to newly perceived environmental needs and opportunities. I identify successes and failures of conservation efforts by organizations in the Monteverde Zone and the factors responsible for them, analyze problems that have been or need to be resolved, and determine the extent to which institutional developments in the Monteverde Zone may serve as models in conservation and sustainable development for other areas.

Birds

Birds have been a major focus of study in Monteverde. The first biologists to study in Monteverde were ornithologists William Buskirk and George Powell, who arrived in 1970 on the recommendation of F. Gary Stiles. They were attracted by the low stature of the cloud forest, which made research on mixed-species flocks more tractable than in tall lowland forests. The number of publications since then (110 as of 1996) and the number of different first authors of those publications (31) attest to the extent to which Monteverde birds have been studied. Sixteen Ph.D. students have written dissertations based largely on data collected on the birds of Monteverde. In comparison, other well-known tropical study sites such as La Selva in Costa Rica or Manú in Peru have supported less graduate work on birds (five and four dissertations, respectively). Two major strengths of the Monteverde bird research are autecological studies and birdplant interaction studies. Although autecological studies may be declining because of changing scientific fashion (Levey and Stiles 1994), studies on single species or small groups of species have abounded at Monteverde. We know much about certain species but have little information about the bird community as a whole. Most studies of avian community ecology in Monteverde have been in the context of interactions with plants. Monteverde’s avifauna is attractive to ornithologists for five reasons: (1) Unusual behaviors: From the perspective of temperate ornithologists, many species of birds in Monteverde exhibit bizarre behaviors. For example, dual-male duets and dances by male Long-tailed Manakins are phenomena that are virtually unique in the animal kingdom (McDonald and Potts 1994; Fig. 6.1; see McDonald, “Cooperation Between Male Longtailed Manakins,”). Similarly, the March- July chorus of Three-wattled Bellbirds, heard for kilometers in every direction, draws attention to this species. Many who walk into a pasture in the dairy community have been mobbed by Brown Jays and wondered about their communal social behavior (Lawton and Guindon 1981, Lawton and Lawton 1985). These vocal species literally cry out to be studied.

Amphibians and Reptiles

Anyone who stood on the bridge over the Río Guacimal at Monteverde on a wet-season night in the early 1980s would understand Archie Carr’s sentiments. Nearly 300 male Fleischmann’s Glass Frogs (Hyalinobatrachium fleischmanni) defended territories along a 120-m section of the stream, and their loud, incessant “peeps” filled the air. In the late 1980s, however, this chorus all but fell silent as the number of glass frogs plummeted. The population has not recovered. In 1998, only a single male could be heard from the bridge. The dramatic reduction in glass frogs was part of a larger decline of Monteverde’s amphibians. A sudden crash of populations in 1987 affected species throughout the area and led to the disappearance of many (Pounds 1990, 1991a, 1997, Crump et al. 1992, Pounds and Crump 1994, Pounds and Fogden 1996, Pounds et al. 1997). The disappearance that has drawn the most attention, however, is that of the Golden Toad (Bufo periglenes). This species, known only from elfin cloud forest high on the ridgetops at Monteverde, is famous for its striking appearance and the colorful spectacle of its breeding congregations (Savage 1966, Jacobson 1983, Fogden and Fogden 1984, Jacobson and Vandenberg 1991; see Savage, “Discovery of the Golden Toad,”. Because the Golden Toad had been locally abundant in seemingly undisturbed habitats for at least 17 consecutive years, its sudden disappearance caused great alarm and dismay (Pounds et al. 1997). Interest in this case has intensified with the suggestion that it is part of a global pattern (Barinaga 1990, Blaustein and Wake 1990, 1995, Phillips 1990, 1994, Wyman 1990, Wake 1991, Wake and Morowitz 1991, Sarkar 1996; see Pounds, “Monteverde Salamanders,”). Many similar declines and disappearances have been reported for highland areas of other continents (Corn and Fogleman 1984, Heyer et al. 1988, Osborne 1989, Weygoldt 1989, Czechura and Ingram 1990, La Marca and Reinthaler 1991, Carey 1993, Fellers and Drost 1993, Kagarise Sherman and Morton 1993, Drost and Fellers 1996, Laurance et al.

Introduction

Monteverde has been variously described as a virgin tropical cloud forest, a Quaker dairy community, an artists’ commune, a haven for those seeking spirituality, a model for tropical rain forest conservation, and a “forest in the clouds” where the sound of the bellbird’s call and images of mist-enshrouded trees long linger in visitors’ minds. The environment of Monteverde is typical of many tropical montane cloud forest regions, but Monteverde provides a unique setting because of its biogeographic, human, and conservation history. This book was created to fulfill three objectives: to compile what we know about Monteverde’s natural history, ecology, and conservation; to identify areas where information is lacking; and to facilitate communication among those who carry out research, education, and conservation. Contributors include a wide range of people with expertise from many different fields, levels of training, and approaches to understanding the natural world, and they have communicated in many modes, ranging from the objective style of scientific prose, statistics, and tables to the more reflective descriptions of personal experiences. In addition to academic scientists, we have invited the voices of farmers, natural history guides, anthropologists, educators, and homemakers, all of whom have important insights into Monteverde’s biology and conservation. In 1951, a band of fewer than fifty North American Quakers bought land and settled in Monteverde (Note that, throughout, when an author refers to another essay in this volume, the essay is cited by author name and a short form of the essay title.) In 1977, visitors to the area were still relatively uncommon. Now, only two decades later, nearly 50,000 visitors walk the trails of Monteverde each year to catch sight of a quetzal or absorb the peaceful outlook of the community. Growth of ecotourism has been phenomenal, eclipsing the small single-family farm as the region’s economic mainstay. New agricultural methods, a changing local, regional, and global economy, and the sheer number of visitors have changed Monteverde and surrounding communities.

Agriculture in Monteverde: Moving Toward Sustainability

This chapter is an overview of how Monteverde settlers transformed their environment into a diversity of agricultural systems. We first discuss “people living in nature,” how Monteverdans have viewed natural resources and defined sustainability. We describe the environmental and social conditions that determined agronomic options in the area, and outline the area’s major agricultural activities (dairy, coffee, and beef), other crops, and efforts at agricultural diversification. Where possible, we cite published studies, but few exist for some issues. We rely heavily on local experts, including long-term community members, local agronomists, veterinarians, and farmers. We also draw on agricultural production data collected by local organizations. From the earliest indigenous settlers to today’s commercial farmers, biologists, and artists, Monteverde’s inhabitants have exhibited a wide spectrum of approaches to natural resource use. The community’s ongoing debate over the meaning and practice of “sustainability” throws into sharp relief residents’ differing worldviews, kinds of knowledge, and perceptions of constraints and opportunities. People’s decisions on how to use natural resources depend on three factors: their attitudes and beliefs, their knowledge, and the opportunities, constraints, and conditions that they confront. For example, beliefs may demand that people be “stewards” of the land, that they use resources to maximize economic returns during their lifetime, or that they use resources as sparingly as possible. Their knowledge may prepare them to be organic vegetable farmers, traditional dairy farmers, business people, or biologists. The social, environmental, and economic context in which they make decisions further defines which options are available or attractive. As one local farmer stated, “We do the best we can with what we have, based on what we know, and what the circumstances permit or encourage us to do.” Monteverdans generally agree that “sustainable agriculture” is a good thing, but there is less agreement on what it means. Following the taxonomy of Gillespie (1998), three sustainable agriculture “schools of thought” exist in Monteverde. The first group is the “Ecocentric Agriculture” school, whose approach focuses on what is sustainable in a biological/ecological sense. Many local biologists and organic producers espouse this view.

Ecosystem Ecology and Forest Dynamics

The earth’s surface supports living organisms and their environments to form the biosphere, a thin film of life around the planet. Organisms participate in interacting systems or communities, and these communities are coupled to their environments by the transfer of matter and energy and by movements of air, water, and organisms. Human activities in Monteverde and elsewhere can drastically alter forest ecosystems. Textbooks on ecosystem ecology typically include such topics as community structure and composition (including plant growth forms, vertical structure, niche space, species diversity), communities and environments (species distributions along environmental gradients, community classification, succession), production (food chains and webs, decomposition and detritus, photosynthesis), and nutrient cycling (mineral nutrition of organisms, soil development, biogeochemistry). Our understanding of tropical ecosystem ecology generally falls short of what we know of other aspects of tropical biology. There are far more studies concerning population biology, autecology, and life history of tropical organisms than nutrient cycling, productivity, and landscape ecology. This pattern is true in Monteverde and in such well-studied tropical forests as La Selva, Barro Colorado Island (BCI), and the Luquillo National Forest (Lugo and Lowe 1995, McDade et al. 1994). Logistical blocks to ecosystem research exist because collaborating teams of scientists are typically needed to tackle the multiple disciplines that ecosystem-level questions require, which demands a large infrastructure and budget. Temporal problems exist because ecosystem-level phenomena (e.g., tree mortality and forest regeneration) may involve time scales longer than the life of a single granting period or lifetime of a researcher. A strong academic base for ecosystem ecology is lacking because the pool of existing studies is too small to draw patterns and extrapolate trends. These obstacles have not often been overcome in Monteverde. No Monteverde institution has provided the infrastructure to support ecosystem research (e.g., laboratory facilities, meteorological station, technical library). Some community members have negative feelings about experimental manipulations and destructive sampling sometimes needed to answer ecosystem ecology questions. From the 1970s to the 1990s, Organization for Tropical Studies (OTS) courses were in Monteverde and in such well-studied tropical forests as La Selva, Barro Colorado Island (BCI), and the Luquillo National Forest (Lugo and Lowe 1995, McDade et al. 1994).

Plant-Animal Interactions

The term “plant-animal interactions” includes a diverse array of biologically important relationships. Plant-herbivore relationships (in which an animal feeds on whole plants or parts of them) are examples of exploitation, because one species benefits from the interaction while the other suffers. Plant-pollinator and plant-seed disperser relationships (in which animals disperse pollen or seeds, usually in return for a food reward) are examples of mutualisms because they are beneficial to both parties. Another class of plant-animal mutualisms involves plants that provide nesting sites and/or food rewards to ants, which often protect the plant from herbivores or competing plants. Plantpollinator and plant-seed disperser mutualisms probably originated as cases of exploitation of plants by animals (Thompson 1982, Crepet 1983, Tiffney 1986). Many of the distinctive plant structures associated with animal-mediated pollen and seed dispersal (e.g., flowers, nectaries, attractive odors, fleshy fruit pulp, and thickened seed coats) presumably evolved to attract consumers of floral or seed resources while preventing them from digesting the pollen or seeds. mutualisms in structuring ecological communities. Competition and predator-prey interactions were more common subjects. Botanists had described the characteristics of the plant and animal players in pollination and seed dispersal mutualisms (Knuth 1906, 1908, 1909, Ridley 1930, van der Pijl 1969, Faegri and van der Pijl 1979), but these descriptive works did not fully examine plant-animal mutualisms in the context of communities. The opportunity to work in the neotropics, facilitated by the Organization for Tropical Studies (OTS), the Smithsonian Tropical Research Institute (STRI), and other institutions, attracted the attention of temperate-zone ecologists to the mutualisms that are much more conspicuous components of tropical systems than of temperate ones (Wheelwright 1988b). Plant-pollinator interactions have attracted more attention in Monteverde than plant-frugivore interactions, and plant-herbivore interactions remain conspicuously understudied. This imbalance probably reflects the interests of those who first worked at Monteverde and later returned with their own students, rather than differences in the significance of the interactions at Monteverde or elsewhere. Aside from a few studies of herbivory in particular species (e.g., Peck, “Agroecology of Prosapia,”), even basic surveys remain to be done.