The bat fauna of Costa Rica’s Reserva Natural Absoluta Cabo Blanco and its implications for bat conservation.

Reserva Natural Absoluta Cabo Blanco, located at the southern tip of northwestern Costa Rica’s Nicoya Peninsula, was established in 1963 and is the country’s oldest nationally protected reserve. Because the climate of the Nicoya Peninsula is ideal for human habitation, the peninsula has been occupied for millennia and is a heavily impacted landscape. The region also is one of the most poorly studied in Central America in terms of biotic diversity. We initiated a multiyear survey of bats in the reserve and the adjacent Refugio de Vida Silvestre Cueva Los Murciélagos to quantify species diversity, abundances, habitat use, seasonality, and reproduction. By surveying bats during 5 rainy seasons and 4 dry seasons from July 1999 through February 2006, we address the following questions: Which species of bats are present in the area? Are the bat communities the same in 3 different habitats—coastal forest, inland forest, and limestone caves? Are the species diversity and abundances of bats in the rainy season similar to those in the dry season? Can we discern seasonal patterns of reproduction? Are the species diversity and abundances of bats at Cabo Blanco (a tropical moist forest in the Holdridge Life Zone classification) similar to those in the nearby tropical dry forest at Parque Nacional Palo Verde? What are the conservation implications of the bat assemblages found in this regenerating forest? Using mist nets, searching for roosting bats, and an acoustical survey, 39 species of bats are documented in the area, including 5 emballonurids, 4 molossids, 1 mormoopid, 1 noctilionid, 21 phyllostomids, and 7 vespertilionids. The 2 most commonly captured bats, Carollia perspicillata and Artibeus jamaicensis, are abundant in both the inland and coastal forests and both are more abundant in the rainy season than in the dry season. Several species have clear habitat preferences, at least during the seasons in which we netted (Glossophaga soricina and Uroderma bilobatum along the coast and Trachops cirrhosus inland). The largest carnivores (Noctilio leporinus, Chrotopterus auritus, Phyllostomus hastatus, Trachops cirrhosus, and Vampyrum spectrum) are present, but the small and middle-sized predatory bats (Micronycteris, Lophostoma, and others) are poorly represented both in terms of diversity and abundance. We captured twice as many bats per hour of effort in the inland forest as we did in the coastal forest. The caves of Refugio de Vida Silvestre Cueva Los Murciélagos have 4 species of bats (Balantiopteryx plicata, Saccopteryx bilineata, Desmodus rotundus, and Phyllostomus hastatus) that are year-round residents. Several species seem to be equally abundant in both seasons, including Balantiopteryx plicata, Saccopteryx bilineata, Noctilio leporinus, Artibeus watsoni, Desmodus rotundus, Glossophaga soricina, Phyllostomus hastatus, Trachops cirrhosus, Lasiurus ega, and Myotis nigricans. Our impression is that some species are more common during the rainy season than the dry season, but more data are needed to substantiate this assertion. Bats in the caves were equally abundant during each of our 8 cave surveys. Desmodus rotundus is the only species for which our data suggest year-round reproduction; we observed scrotal males, pregnant females, and juveniles during each of our visits to Cabo Blanco. Other species are present year-round but have seasonal reproductive activity. We captured Artibeus watsoni and Carollia perspicillata in both seasons but have seen pregnant females only during the rainy season. Carollia perspicillata and Artibeus jamaicensis are the 2 most commonly captured bats at both Cabo Blanco and the nearby Parque Nacional Palo Verde. The species records and abundances of several other species differed between the sites, however. Species that are abundant at Palo Verde, but not yet recorded from Cabo Blanco, include Pteronotus davyi, Pteronotus gymnonotus, Carollia subrufa, Centurio senex, and Natalus stramineus. Phyllostomus hastatus is abundant at Cabo Blanco but not known from Palo Verde. Although both sites are relatively close together in the northern Pacific lowlands of Costa Rica, Cabo Blanco is substantially wetter, and the associated differences in vegetation may be driving bat distributional patterns. We provide a number of new records and ecological information for bats on the Nicoya Peninsula and document that bat diversity and abundances can be substantial in regenerating forest. Several of the most commonly captured bat species are seed dispersers and may be critical to forest regeneration

Mammals of Cabo Blanco: History, diversity, and conservation after 45 years of regrowth of a Costa Rican dry forest

Reserva Natural Absoluta Cabo Blanco, a strongly seasonal deciduous forest located at the southernmost tip of northwestern Costa Rica's Nicoya Peninsula, was established in 1963 and is the country's oldest nationally protected reserve. The peninsula has been occupied for millennia and is a heavily impacted landscape, and, unfortunately, its biotic diversity is among the most poorly studied in Central America. As part of multiyear studies of the flora and fauna of the region, we assess the changes in vegetation and the terrestrial mammal community from earlier times to the present day. Through historical records, interviews with long-term residents of the area, and our studies over the past decade, we document changes in forest cover, settlement, and land use, and assess the changes in species diversity and in mammal species’ abundance. We then discuss the ecology of the mammal species on the peninsula, emphasizing the role that humans have played in influencing population levels. After 45 years of protection, the forest structure of the 3100 ha reserve differs markedly from that observed in the early 20th Century and it is quite heterogeneous. Species diversity of both the native vegetation and the mammals is substantial in the regenerating forest. The known mammal fauna included at least 37 species of non-flying mammals and 39 species of bats. Six species (Geoffroy's Spider Monkey, Giant Anteater, White-lipped Peccary, Central American Red Brocket Deer, Baird's Tapir, and Jaguar) have been extirpated from the reserve. Poaching of game species continues and will be difficult to eliminate completely. Nevertheless, with regenerating habitats, coupled with protection of wildlife, reestablishment of the reserve's native species has been dramatic both in terms of species diversity and abundance. The reserve is not in a defaunated condition. Many mammalian frugivores, seed dispersers, and/or seed predators are common and most top mammalian predators are present. We present several testable hypotheses regarding the significance of this mammalian community in the context of other Neotropical forest mammal and plant communities. Rapid expansion of tourism in this region has the potential to affect the reserve adversely. In recent years, the reserve has served as an important site for teaching tropical biology courses. Small reserves, such as Cabo Blanco, even if not connected to larger protected areas through corridors, provide critical habitat for native flora and fauna, a source of genetic stock, and valuable regional teaching and research sites

Field Identification of the Mice Peromyscus leucopus noveboracensis and P. maniculatus gracilis in Central New York

Field identification of the White-footed Mouse (Peromyscus leucopus noveboracensis) and Long-tailed Deer Mouse (Peromyscus maniculatus gracilis) is difficult because of their similar external morphology. Peromyscus were sampled by live-trapping during a five-year period (1992-1996) at the Arnot Teaching and Research Forest, Van Etten, New York and identified to species by electrophoresis of their salivary amylase. No electromorphs were shared between P. leucopus and P. maniculatus, thus permitting unambiguous species identification of individuals. Means and ranges of four external measurements (ear, head-body, hind-foot, and tail) and tail to head-body ratio were determined for amylase-genotyped live mice. Although some body measurements did differ on average between the two species (ear, head-body, and tail for adults; hind-foot and tail for juveniles), the ranges of these overlap considerably. When the four external measurements (excluding the tail to head-body ratio) were used to construct two discriminant-function equations, they yielded correct identification of 80% of the adult P. l. noveboracensis and P. m. gracilis assessed excluding juveniles, and 71% of adult and juvenile mice combined. The function reported here allows partial field identification, but genetic analysis remains the only reliable field method for differentiation between live P. l. noveboracensis and P. m. gracilis. Includes erratum for a figure in this article

Group dynamics, behavior, and current and historical abundance of peccaries in Costa Rica’s Caribbean lowlands

The abundances and habitat preferences of peccaries in Neotropical forests are important to understand because these keystone species influence many aspects of the ecosystem. In the Caribbean lowlands of Costa Rica, we conducted walking surveys for ~2 years to study the behavior and population trends of collared peccaries (Pecari tajacu), and found that peccaries are abundant at La Selva Biological Station and overall, detection rates were relatively constant through time. A stable estimate of detection rates was achieved only after 7–9 months of surveying. We found no habitat preferences between primary and secondary forest, yet there were some differences in group dynamics—group radius was larger and sighting distance was greater in primary forest, whereas the number of singletons was higher in secondary forest. More peccaries were seen closer to the laboratory clearing than at greater distances, for a variety of probable reasons: habituation to humans, lower predation and hunting pressure, and various environmental and habitat factors. Peccary groups had spatially clumped distributions across the landscape and were more active diurnally than nocturnally. Collared peccary densities are relatively high at La Selva compared to other Neotropical sites, with the exception of Barro Colorado Island. We combined our data with a review of the historical literature to assess changes in the populations of peccaries in the Caribbean lowlands. We found that collared peccaries have likely increased in abundance at La Selva, seemingly a few years after the extirpation of white-lipped peccaries (Tayassu pecari), which were abundant in the area 40–50 years ago. An understanding of the group dynamics, behavior, and habitat preference of collared peccaries is essential for management decisions and conservation efforts. Additionally, assessment of population changes should be carefully considered in a historical context, with a particular focus on how the populations of the 2 peccary species have changed, and how these species might differentially affect their environment. Resumen--Entender la abundancia y la preferencia de hábitat de las 2 especies de sainos en bosques neotropicales es importante porque estas especies clave afectan muchos aspectos del ecosistema. En las tierras bajas del Caribe costarricense, llevamos a cabo muestreos a pie durante ~2 años para estudiar el comportamiento y tendencias poblacionales del saino (Pecari tajacu), y encontramos que son abundantes en la Estación Biológica La Selva y las tasas de detección fueron relativamente constantes a través del tiempo. Se obtuvo una tasa estable de detección después de 7–9 meses de muestreos. Las tasas de detección fueron similares en bosque primario y secundario, sin embargo, se encontraron algunas diferencias en la dinámica de grupo (el radio de distribución del grupo era más grande y distancia de observación fue mayor en bosques primarios, mientras que el número de individuos solitarios fue mayor en bosques secundarios). Más sainos fueron vistos alrededor de las zonas abiertas rodeando el laboratorio, debido a varias posibles razones: habituación a la presencia de seres humanos, menos presión por depredación o cacería y otros factores ambientales o de hábitat. Los sainos están distribuidos de forma aglomerados y son más activos de día que de noche. Las densidades de sainos son relativamente altas en comparación con otros sitios neotropicales, con excepción de la Isla de Barro Colorado. El saino probablemente ha aumentado en abundancia en La Selva, aparentemente unos años después de la extirpación del cariblanco (Tayassu pecari), que eran abundantes en el área hace unos 40–50 años. El conocimiento de la dinámica de grupos, comportamiento y preferencias de hábitat del saino es esencial para las decisiones de manejo y los esfuerzos de conservación. Además, la evaluación de los cambios poblacionales debe considerarse cuidadosamente en un contexto histórico, con especial atención a cómo han cambiado las poblaciones del saino y cariblanco, y cómo estas especies afectan su ambiente

Integrating tropical research into biology education is urgently needed

Understanding tropical biology is important for solving complex problems such as climate change, biodiversity loss, and zoonotic pandemics, but biology curricula view research mostly via a temperatezone lens. Integrating tropical research into biology education is urgently needed to tackle these issues. The tropics are engines of Earth systems that regulate global cycles of carbon and water, and are thus critical for management of greenhouse gases. Compared with higher-latitude areas, tropical regions contain a greater diversity of biomes, organisms, and complexity of biological interactions. The tropics house the majority of the world’s human population and provide important global commodities from species that originated there: coffee, chocolate, palm oil, and species that yield the cancer drugs vincristine and vinblastine. Tropical regions, especially biodiversity hotspots, harbor zoonoses, thereby having an important role in emerging infectious diseases amidst the complex interactions of global environmental change and wildlife migration [1]. These well-known roles are oversimplified, but serve to highlight the global biological importance of tropical systems. Despite the importance of tropical regions, biology curricula worldwide generally lack coverage of tropical research. Given logistical, economic, or other barriers, it is difficult for undergraduate biology instructors to provide their students with field-based experience in tropical biology research in a diverse range of settings, an issue exacerbated by the Coronavirus Disease 2019 (COVID-19) pandemic. Even in the tropics, field-based experience may be limited to home regions. When tropical biology is introduced in curricula, it is often through a temperate- zone lens that does not do justice to the distinct ecosystems, sociopolitical histories, and conservation issues that exist across tropical countries and regions [2]. The tropics are often caricatured as distant locations known for their remarkable biodiversity, complicated species interactions, and unchecked deforestation. This presentation, often originating from a colonial and culturally biased perspective, may fail to highlight the role of tropical ecosystems in global environmental and social challenges that accompany rising temperatures, worldwide biodiversity loss, zoonotic pandemics, and the environmental costs of ensuring food, water, and other ecosystem services for humans [3]

Averting biodiversity collapse in tropical forest protected areas

The rapid disruption of tropical forests probably imperils global biodiversity more than any other contemporary phenomenon¹⁻³. With deforestation advancing quickly, protected areas are increasingly becoming final refuges for threatened species and natural ecosystem processes. However, many protected areas in the tropics are themselves vulnerable to human encroachment and other environmental stresses⁴⁻⁹. As pressures mount, it is vital to know whether existing reserves can sustain their biodiversity. A critical constraint in addressing this question has been that data describing a broad array of biodiversity groups have been unavailable for a sufficiently large and representative sample of reserves. Here we present a uniquely comprehensive data set on changes over the past 20 to 30 years in 31 functional groups of species and 21 potential drivers of environmental change, for 60 protected areas stratified across the world’s major tropical regions. Our analysis reveals great variation in reserve ‘health’: about half of all reserves have been effective or performed passably, but the rest are experiencing an erosion of biodiversity that is often alarmingly widespread taxonomically and functionally. Habitat disruption, hunting and forest-product exploitation were the strongest predictors of declining reserve health. Crucially, environmental changes immediately outside reserves seemed nearly as important as those inside in determining their ecological fate, with changes inside reserves strongly mirroring those occurring around them. These findings suggest that tropical protected areas are often intimately linked ecologically to their surrounding habitats, and that a failure to stem broad-scale loss and degradation of such habitats could sharply increase the likelihood of serious biodiversity declines.Keywords: Ecology, Environmental scienc

Nonvolant mammalian populations in primary and secondary Neotropical rainforests as revealed by transect surveys.

Secondary forests are now prominent features in Neotropical landscapes, yet little is known about their conservation value for nonvolant mammalian communities. We performed a 20-month study using transect walks to survey the nonvolant mammal fauna in primary and secondary forests at La Selva Biological Station in the Caribbean lowlands of northeastern Costa Rica. We found that secondary forests can hold complex mammalian communities and no species exhibited habitat preferences between primary and secondary forests. With few exceptions, behavioral and group dynamic characteristics of mammal species were similar between forest types. Our research allows us to address methodological questions and assess the effectiveness of transect sampling. Monthly detection rates vary widely by species and likely reflect short-term changes in behavior rather than population fluctuations. Air temperature and rainfall are the factors most associated with monthly detection rates for various species. Small-scale areas of higher and lower use are evident for several species. Neither time of morning for surveys nor number of observers per trail affects detection rate. We report current abundances for the most commonly observed species and note generally lower densities in the Caribbean lowlands than elsewhere in the Neotropics. This research highlights that in less seasonal, evergreen forests climatic factors can still affect mammalian behavior. Overall, we find that secondary forests are of high conservation value and that transect walks are an effective methodology to sample many nonvolant mammal species, and we present recommendations on how to sample properly to conduct rigorous and long-term studies. Los bosques secundarios son mucho más comunes en el neotrópico, pero poco se sabe sobre su importancia en la conservación de comunidades de mamíferos no voladores. Durante 20 meses llevamos a cabo un estudio usando líneas de transectos para investigar la fauna de mamíferos no voladores en bosques primarios y secundarios en la Estación Biológica La Selva en las tierras bajas caribeñas al noreste de Costa Rica. Pudimos constatar que los bosques secundarios pueden albergarcomplejas comunidades de mamíferos y ninguna especie exhibe preferencias de hábitat entre bosque primario y secundario. Con pocas excepciones, las características dinámicas de grupo y comportamiento de especies de mamíferos fueron similares entre los dos tipos de bosque. Nuestra investigación nos permite abordar cuestiones metodológicas y evaluar la eficacia del muestreo con transectos. Las tasas mensuales de detección varían de acuerdo a la especie y probablemente reflejan cambios a corto plazo en las fluctuaciones del comportamiento en vez de la población. La temperatura del aire y la precipitación son los factores más asociados con las tasas mensuales de detección de distintas especies. Encontramos que varias especies muestran diferentes incidencias de uso en zonas pequeñas. Ni la hora de la mañana, ni el número de observadores en las encuestas por transecto afectan la tasa de detección. Presentamos la abundancia actual de las especies más comúnmente observadas y notamos en general bajas densidades en las tierras bajas del Caribe más que en otras partes del neotrópico. Esta investigación resalta que en los bosques menos estacionales, factores climáticos aún pueden afectar el comportamiento de mamíferos. En general, encontramos que los bosques secundarios son de alto valor para la conservación y que los muestreos en transectos son una metodología eficaz para estudiar muchas especies de mamíferos no voladores y presentamos recomendaciones sobre cómo llevar a cabo muestreos adecuados para realizar estudios rigurosos a largo plazo

Erratum: Field Identification of the Mice Peromyscus leucopus noveboracensis and P. maniculatus gracilis in Central New York. (2003) 117(2): 184-189.

On page 4, Figure 1, 1A was repeated for 1B. The correct 1B is shown below with 1A