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Wild felid species richness affected by a corridor in the Lacandona forest, Mexico
(Museu de Ciencies Naturals, Barcelona, 2017) Gil Fernández, Margarita; Muench, Carlos; Gómez Hoyos, Diego A.; Dueñas, Ariel; Escobar-Lasso, Sergio; Aguilar Raya, Gustavo; Mendoza, Eduardo
Los efectos de la presencia de un corredor en la selva Lacandona, en México, en la riqueza de especies de félidos silvestres.— Los félidos silvestres se encuentran entre las especies más vulnerables ante la pérdida de hábitat causada por la fragmentación de los ecosistemas. Se analizó el efecto de la presencia de un corredor estructural, definido como una franja de vegetación que conecta dos fragmentos de hábitat, en la riqueza y ocupación de félidos en tres sitios de Marqués de Comillas, en Chiapas: uno comprende dos fragmentos de bosque aislados, otro presenta un corredor estructural y el último se encuentra dentro de la reserva de la biosfera Montes Azules. Se encontraron cuatro especies en el interior de la Reserva, cinco en el corredor estructural y únicamente dos (L. pardalis y H. yagouaroundi) en los fragmentos de bosque aislados. La presencia del corredor no afectó de forma significativa a la ocupación, pero debido a la baja tasa de detección, se necesita seguir investigando para descartar diferencias. Nuestros resultados resaltan la necesidad de manejar la conectividad del hábitat en los bosques remanentes para lograr la conservación de la comunidad de félidos en Marqués de Comillas, en Chiapas, México.
Evaluación de algunos efectos de la extracción tradicional de bromelias sobre la herpetofauna de los bosques de Chanal, Chiapas
(Instituto de Ecología, A.C., México., 2012-12-05) Aranda Coello, J. Manuel; Ochoa Ochoa, Leticia M.; Naranjo Piñera, Eduardo J.
Durante la celebración del “Niño Florero” en Chiapas cada diciembre, se recolectan bromelias para formar ofrendas florales al Niño Jesús. En este proceso mueren anfibios y reptiles provocando pérdidas de esos organismos en los bosques de pino-encino. El trabajo de campo se realizó en los bosques de Chanal, Chiapas; y consistió en muestreo directo de bromelias y entrevistas a recolectores de plantas. Encontramos que el animal más sacrificado es una especie endémica, Abronia lythrochila. Proponemos tres estrategias de conservación para lograr la sostenibilidad en el largo plazo: reducción del volumen de extracción de bromelias, talleres de educación ambiental y establecimiento de zonas protegidas.
First record of leucism for Carollia castanea Allen, 1890 (Phyllostomidae: Carollinae) in southeastern Costa Rica
(Universidad de Murcía, España, 2017-10-03) Mejía Quintanilla, David Josué; Gómez Hoyos, Diego; Seisdedos de Vergara, Rocío; Rodríguez, Bernal; González Maya, José
Carollia castanea se distribuye desde Honduras hasta Venezuela. Casos de leucismo no han sido reportados para esta especie pero si para otros filostómidos. Capturamos un adulto de C. castanea con leucismo en la Zona Protectora Las Tablas. Presentaba despigmentación en la punta de las alas, debajo del antebrazo y en la parte superior del uropatagio, pero las manchas blancas no cubrían una alta porción de la piel. Algunos casos de leucismo en murciélagos han sido explicados por endogamia en poblaciones pequeñas o aisladas, pero esto no está apoyado por evidencia empírica. Nuestro registro es anecdótico, y no podemos ofrecer una explicación ecológica o genética. Proponemos que los casos de leucismo sean evaluados en cada contexto específico y soportado por estudios poblacionales robustos.
Relación entre las comunidades de aves y la vegetación en agropaisajes dominados por la ganadería en Costa Rica, Nicaragua y Colombia
(Centro Agronómico Tropical de Investigación y Enseñanza (CATIE), 2007-01-01) Sáenz, Joel C.; Villatoro, Federico; Ibrahim, Muhammad Akbar; Fajardo, David; Pérez, Mijail
Los ecosistemas son naturalmente fragmentados, pero la defo restación y fragmentación antropogénica ha sido severa durante el último siglo. Por lo tanto, es esencial identificar patrones de paisaje críticos para la conservación de aves en ecosistemas con manejo silvopastoril. Se evaluó y comparó la riqueza de especies de aves en tres agropaisajes en Nicaragua, Costa Rica y Colombia. Se encontraron 154 especies de aves en el paisaje de Nicaragua, 111 en Costa Rica y 170 en Colombia. Un 4% de las especies de Matiguás son dependientes de bosques, 64% necesitan al menos fragmentos de bosques para su supervivencia y 10% tienen pobla ciones reducidas. En Esparza, los valores alcanzaron un 33,2; 60,5 y 6,3%, respectivamente. En el río La Vieja, el 11% de las aves son dependientes de bosque y el 54% dependen de fragmentos de bosque. La riqueza de aves mostró diferencias significativas entre usos del suelo en todos los sitios. Las pasturas naturales con alta densidad de árboles albergaron la mayor riqueza de aves en Matiguás y el río La Vieja, y las cercas vivas en Esparza. Se encon tró mayor similitud entre los usos del suelo en Esparza que en Matiguás y en el río La Vieja. El análisis de correspondencia canó nica seleccionó dos variables de la vegetación leñosa que explican la riqueza de aves en el paisaje de Esparza: la cobertura del dosel (%) y la riqueza de la vegetación, mientras que en Matiguás solo la cobertura de dosel fue importante. En el río La Vieja, las variables explicativas de la riqueza de aves fueron la densidad de árboles y la cobertura del dosel. Las prácticas silvopastoriles (cercas vivas y pasturas arboladas) están desempeñando un papel importante en mantener la riqueza de aves en los paisajes ganaderos de los tres países.
Riqueza, abundancia y diversidad de aves y su relación con la cobertura arbórea en un agropaisaje dominado por la ganadería en el trópico subhúmedo de Costa Rica
(Centro Agronómico Tropical de Investigación y Enseñanza (CATIE), 2013-06-27) Enríquez Lenis, Martha L.; Sáenz, Joel C.; Ibrahim, Muhammad Akbar
En Centroamérica, el establecimiento de pasturas se ha convertido en una de las principales causas de la deforestación, originando paisajes fragmentados con parches de bosque, pasturas y cultivos agrícolas. La transformación del paisaje ha modificado las poblaciones de aves y su composición. Por lo tanto, es importante establecer rangos de cobertura arbórea a nivel de fincas y agropaisajes dominados por ganadería que contribuyan con la conservación de la fauna aviar. Se caracterizó la comunidad de aves y la vegetación en 12 fincas ganaderas de Esparza, Costa Rica, para evaluar la relación entre la riqueza, abundancia y diversidad de aves y la cobertura vegetal del paisaje. Se identificaron los sistemas de usos de la tierra existentes en cada finca y en el centro de éstos se ubicaron puntos de conteo de aves. El muestreo de la vegetación se realizó en el mismo sitio del muestreo de aves. Además se midieron la cobertura de dosel y el volumen de vegetación hasta una altura de 3 m. Se registraron 1901 individuos de 113 especies de aves, 31 familias y 9 géneros. La diversidad gama de aves fue de 126 especies según el modelo de Clench, con un esfuerzo de muestreo del 90 por ciento. Las especies residentes abundantes fueron Crotophaga sulcirostris (Tijo) y Melanerpes hoffmannii (Carpintero de Hoffmann), y las migratorias Dendoica petechia (Reinita amarilla) e Icterus galbula (Bolsero norteño). La presencia de aves dependientes de fragmentos de bosque estuvo relacionada con el área de bosques en las fincas. Este estudio destaca la importancia de los fragmentos de bosque y la cobertura arbórea de las fincas para la conservación de las aves. Se sugiere que en los planes de manejo de las fincas se promueva la implementación de los sistemas silvopastoriles y se procure mantener los fragmentos de bosque.
Observations on the role of frugivorous bats as seed dispersers in Costa Rican secondary humid forests
(BioOne Digital Library, 2004) Lopez, Jorge E.; Vaughan, Christopher
The role of frugivorous bats as seed dispersers in humid neotropical tropical forests was evaluated between January and August 1995. Thirty germination trials were set up using seeds defecated by six bat species. Seeds of Piper multiplinervium and Ficus insipida, defecated by Carollia brevicauda and Artibeus jamaicensis, respectively, showed significantly higher germination percentages than seeds not ingested by bats. Of seven seed species regurgitated by bats, only Markea neurantha showed significant increases in percent germination compared to seeds not ingested by bats. Of 19 tents and three active feeding roosts found, 12 tents and three feeding roosts were in primary forest, while six tents were in abandoned plantations. For tent construction, four bat species used six plant species. Fifty-two percent of seeds found under tents and feeding roosts were from secondary forest species. Twenty-two percent of seed species in fecal samples from netted bats in three secondary forest types were primary forest species. Bats in our study dispersed seeds between different habitat types.
Demographic survey of black howler monkey (Alouatta pigra) in the Lachuá Eco-region in Alta Verapaz, Guatemala
(Wiley-Liss, Inc., 2008-03) Rosales Meda, Marleny; ESTRADA, ALEJANDRO; López, Jorge E.
Guatemala alberga tres especies de primates (Alouatta palliata, Alouatta pigra y Ateles geoffroyi), pero la distribución y el estado de conservación de las poblaciones de estas especies están poco documentados. En el caso de A. pigra, las poblaciones han sido estudiadas y documentadas recientemente en varios sitios de México y Belice, y sólo en un sitio en Guatemala (Parque Nacional Tikal). En este estudio, reportamos por primera vez datos de la población de A. pigra existente en la Ecorregión Lachuá en el noroeste de Guatemala. Los censos se realizaron entre septiembre de 2002 y abril de 2003 en la porción norte (32 km2) del Parque Nacional Lachuá (PNLL; 145 km2) y en un paisaje fragmentado al norte del área protegida. En esta última área estudiamos un gran fragmento de bosque (17,14 km2), “Nueve Cerros”, y 26 pequeños fragmentos de bosque que oscilaban en tamaño entre 0,01 y 3,9 km2. Las encuestas dieron como resultado un recuento total de 414 monos aulladores, de los cuales 403 pertenecían a 80 grupos de sexos mixtos, cuatro eran machos solitarios, dos eran hembras solitarias y cinco se encontraban en dos grupos de machos. El esfuerzo de muestreo estandarizado entre sitios indicó 16.7 monos/100 horas de estudio en el LLNP, 35.8 individuos/100 horas de estudio en “Nueve Cerros” y 71.0±62.2 individuos/100 horas de estudio en los fragmentos de bosque. El tamaño medio del grupo varió de 4,07 individuos en el LLNP a 5,19 individuos en los fragmentos de bosque. Se discuten los problemas de conservación de la población de aullador negro estudiada, junto con posibles escenarios de conservación.
Occupancy and probability of detection of the introduced population of Eleutherodactylus coqui in Turrialba, Costa Rica
(Firenze University Press, 2022-07-28) Barrantes-Madrigal, Jimmy; Spínola-Parallada, Manuel; Alvarado, Gilbert; Acosta-Chaves, Víctor José
The Puerto Rican Common coqui frog (Eleutherodactylus coqui) has a long history as an invasive species in places such as Hawaii. Since its introduction in Costa Rica, scarce information is available to understand why and how the habitat in the Turrialba town is suitable for the species. Our goal was to analyze the habitat selection of E. coqui to identify if there are key habitat features that explained its success there. We measured 9 site variables that may affect the habitat selection of E. coqui in 92 survey units of 10 m radius distributed over a 500 m radius from its introduc-tion point. We registered the presence/pseudo-absence data of E. coqui and environmental variables in each survey unit during eight surveys. We ran occupancy models to determine the influence of the variables on the habitat selec-tion and to estimate its detection probability. We found that sites near the introduction point, containing abundant vegetation, bromeliads, and palms have a higher probability to be occupied by E. coqui. The habitat selection in Costa Rica shares characteristics with the populations of Puerto Rico and Hawaii. But, unlike the case in Hawaii, in Costa Rica this species has maintained a limited dispersal because the potentially higher biotic resistance, as well a sedentary behavior. However, the microhabitat conditions used by E. coqui in the study site are common throughout the coun-try. Therefore, active management in new populations and environmental education programs to avoid human trans-portation of the species is critical to reduce its dispersal.
Soundscape structure in forests surrounded by protected and productive areas in central Costa Rica
(Universidad Nacional, Costa Rica, 2023-03-09) Retamosa Izaguirre, Monica; Barrantes Madrigal, Jimy
Ecosystems are under a multitude of pressures, including land-use change, overexploitation, pollution, and climate change. Most studies, resources, and conservation efforts are allocated to protected areas, while anthropogenic activities in their surroundings may affect them in ways that are poorly understood. We evaluated soundscape structure in forests surrounded by protected or productive areas in central Costa Rica. We sampled soundscapes in 91 recording sites in Grecia Forest Reserve and Poas Volcano National Park, and surrounding areas with productive activities (predominantly agricultural and urban). We classified sampling sites into three clusters according to landscape entropy, forest amount, and fragmentation surrounding recording points: more fragmented, more conserved, and intermediate. The conserved cluster showed higher acoustic diversity or entropy, but lower acoustic complexity, shorter duration of sounds in all frequency ranges, and lower amount of energy in the biological frequency bands than the fragmented cluster. We additionally found a positive significant relationship between the amount of forest and acoustic entropy or diversity indices, but a negative relationship with acoustic activity or energy indices. Indices, such as spectral and temporal entropy, the entropy of spectral variance, and total entropy, seemed to be a better fit than acoustic complexity and bioacoustic indices as indicators of habitat conservation in this study. Acoustic indices revealed that the surrounding matrices of protected areas have an impact on acoustic environments. We encourage researchers and decision-makers to carefully interpret acoustic indices when evaluating habitats showing a higher value in acoustic energy or activity because this might not necessarily reflect either a high level of biodiversity or habitat conservation. Also, we highlight the importance of preserving undisturbed forested matrices around protected areas, as they are important for maintaining acoustic diversity.
Neotropical dry forest wildlife water hole use and management
(Universidad Nacional, Costa Rica., 1999) Vaughan, Christopher; Weis, Kelly
Selected wildlife species diurnal use of a natural water hole (QO) and an artificial water hole (AW) were studied during 1990 dry season at Guanacaste Conservation Area, Costa Rica. In total, 919 individuals (six marnmal and one garne bird species) consumed water from QO, while 713 individuals (four maromal species) consumed water from AW. Estimated daily water consumption by selected wildlife species was 29.7 I at O.D and 27.3 I at AW. Estimated 24-h water consumed by all wildlife species or evaporated was 44.6 1 at QO and 41.1 1 at AW. This resulted from summing: a) water consumed by studied species, b) estimated 24-hour water consurned by other wildlife (QO = 14.851, AW = 13.65 1) and c) daily water evaporation (QO = 0.041, AW = 0.10 1). Ouring a 120-day dry season, AW required about 4 932 1 of water from the park administration. Management implications for neotropical dry forest water holes are discussed.
Movements and activities of white-lipped peccaries in Corcovado National Park, Costa Rica
(Universidad Nacional, Costa Rica., 2002) Carrillo, Eduardo; Saenz, Joel C.; Fuller, Todd K.
The conservation of remnant populations of white-lipped peccaries in Central America depends on adequate documentation of their habitat needs and behavior. Thus, we monitored the activity patterns, local distributions, and home ranges of 36 (25F:11M) radio-marked white-lipped peccaries, all members of a single ‘‘super’’ herd, in part of Corcovado National Park, their largest stronghold in Costa Rica, during 1996–1998. Peccaries were diurnal all year with a period of reduced activity during the middle of the day. They were found more often than expected (vs. random use) in primary forest during February to May, in secondary and coastal forest during June to September, and in herbaceous swamp during October to January, corresponding to relative fruit abundance. Overall, the peccary herd ranged over an area of <40 km2 , but use of the area shifted seasonally and movements were reduced when fruit was most abundant. Our data agree with the suggestion that peccary density may be higher where the inter spersion or close proximity and mix of seasonally important habitats is high, and thus where peccaries do not have to travel as far for food. Habitat interspersion is therefore a significant conservation concern and should be addressed to make certain that peccary populations are not limited.
Long-term comparison of the fish community in a Costa Rican rocky shore marine reserve
(Universidad Nacional, Costa Rica., 2010) Myers, Mark C.; Wagner, Jonathan; Vaughan, Christopher
Despite their role in supporting diverse marine fish communities, tropical rocky shores and reefs have attracted less research and fewer targeted conservation efforts compared to coral reefs. We studied fish community composition in Playa Blanca Marine Reserve (9˚40’ N - 84˚40’ W), a rocky shore site on the central Pacific coast of Costa Rica. We conducted visual surveys of fishes along six strip transects soon after the area was designated a marine reserve in 1995, then again in 2006 following an eleven-year period of complete pro tection. We recorded a total of 31 406 sightings of 72 species from 30 families. Pomacentrids (42.5%), labrids (16.6%) and haemulids (14.8%) dominated the community, accounting for >70% of total fish abundance. In comparison to other sites in the region, the fish community was more similar to one reported from Bahia Honda, Panama (7˚50’ N - 81˚35 W) than from the geographically more proximate Culebra Bay, Costa Rica (10˚45’ N - 85˚43 W). Sixty-one species from 26 families were recorded in 1995; sixty-nine species from 28 families in 2006. Our results suggest that the Playa Blanca Marine Reserve is fulfilling its conservation role. Average fish abundance, species richness and Shannon’s index of community diversity were greater in 2006 than 1995, and fish community composition varied significantly within each transect among years. Much of the change in community composition among years resulted from spatial and temporal variation in the abundance of a few dominant species, including Abudefduf troschelli, Thalassoma lucasanum, Chromis atrilobata, and Stegastes flavilatus/acapulcoensis. Of the 48 species/species groups recorded in both years, 37 (77%) were more abundant in 2006 than 1995, and several species recorded as uncommon or rare in 1995 were more frequent and abundant in 2006. Fish community composition and the abundance of some species changed in the reserve over time, but further study is needed to determine the role of small-scale marine reserves in the conservation of tropical marine biodiversity. Rev. Biol. Trop. 59 (1): 233-246. Epub 2011 March 01
Late dry season habitat use of common opossum, Didelphis marsupialis (Marsupialia: Didelphidae) in neotropical lower montane agricultural areas
(Universidad Nacional, Costa Rica., 1999) Vaughan, Christopher S.; Foster Hawkins, L.
Three Didelphis marsupialis were radio tracked during late dry season (23 February-26 April, 1983) in agricultural area at 1500 m elevation in Central Valley, Costa Rica. All animals were nocturnally active, significantly more so between 2100-0300 h. Fifty diurnal den site locations were found, 96% inside tree cavities in living fence rows or abandoned squirrel nests in windbreaks. Two females occupied 3.4 and 3.1 ha 95% home ranges, moving an average 890 and 686 m nightly respectively. The male occupied a 5.6 ha 95% home range for 42 days overlapping 90% of females’ home ranges. Over the next 15 days, he moved 1020 m south, establishing three temporary home ranges. During nocturnal movements, windbreaks and living fence rows were used in higher proportion than available, while pasture, roads and cultivated lands were used less then available within 100% home ranges. Abandoned coffee and spruce plantations, fruit orchards and overgrown pastures were used in equal proportions to availability in 100% home ranges. Opossum conservation techniques in coffee growing areas include promoting spruce windbreaks, living fence rows, and garbage dumps.
Jaguars (Panthera onca) increase kill utilization rates and share prey in response to seasonal fluctuations in nesting green turtle (Chelonia mydas mydas) abundance in Tortuguero National Park, Costa Rica
(Universidad Nacional, Costa Rica., 2015) Guilder, James; Barca, Benjamin; Arroyo-Arce, Stephanny; Gramajo, Roberto; Salom-Pérez, Roberto
Jaguar (Panthera onca) predation of green turtles (Chelonia mydas mydas) is now a common occurrence in Tortuguero National Park, Costa Rica. The abundance of green turtles during nesting season ensures a constant provision of easy and predictable prey, however it is unknown to what extent jaguars con sume turtle carcasses and how the jaguar population responds to limited turtle availability outside of nesting season. This study took advantage of the accessible nature of jaguar-predated turtle carcasses on Tortuguero Beach over a two year period (2011–2013), to provide a novel analysis of carcass utiliza tion rates by jaguars and determine the effects of temporal fluctuations in green turtle nesting numbers. Camera traps were set-up on freshly predated turtles to capture jaguar activity across both Peak and Non Peak green turtle nesting seasons. Thirteen individual jaguars (five males, five females, three cubs) were captured returning to 77% of monitored turtle kills (60% Peak; 95% Non Peak). During Non Peak season, the number of jaguars per kill increased (H(1) = 15.91, p < 0.001) and total jaguar feeding time per kill also increased (H(1) = 13.34, p < 0.001). The propensity for tolerated scavenging or sharing during Non Peak season is illustrated by four adult jaguars captured interacting with a kill at separate times over two nights in October, 2012 (two males, two females). There were no significant differences between males and females, although there is a tendency for the latter to handle the prey to a greater extent. Although marine turtles may notto be a primary prey species,they play an important role in subsidizing the jaguars in this study. The increased kill utilization rates and prey sharing displayed by the jaguars, ensures opti mal foraging during periods of low prey availability. These apparently atypical feeding behaviors may be unique to Tortuguero, however their prevalence across the jaguar’s range should be considered.
Interbirth interval of a free-ranging jaguar
(Universidad Nacional, Costa Rica., 2009) Carrillo, Eduardo; Saenz, Joel; Fuller, Todd
The 60-kg adult female jaguar was first captured on 25 February 1996 in a box trap baited with shark meat. We monitored her for the next three and a half years, usually locating her by triangulation once or twice a week, but also by tracking her (i.e., following sets of footprints to identify individuals) to within 100 m. She was recaptured once but released immediately.
Cetáceos de las aguas costeras del Pacífico norte y sur de Costa Rica
(Universidad Nacional, Costa Rica., 2010) Martínez-Fernández, Damián; Montero-Cordero, Andrea; May-Collado, Laura
Cetáceos costeros del Pacífico Norte y Sur de Costa Rica. Veintinueve especies de cetáceos ocurren en aguas costarricenses pero sólo se han realizado investigaciones extensivas para tres especies. Esto último demuestra que hay una falta de información general y local sobre estos mamíferos, incluso cuando el país, ha mostrado un notable crecimiento en las actividades de observación de ballenas. El creciente uso de los recursos marinos en las zonas costeras también ha desarrollado la necesidad de determinar la ocurrencia de cetáceos en áreas de alta presencia turística, con el fin de proponer medidas de conservación adecuadas. En este estudio se determinaron las variables ambientales y posteriormente se relacionaron con la presencia de las especies registradas, de un total de 166 avistamientos, entre 2005 y 2006. Las especies con mayor proporción de avistamientos fueron Stenella attenuata (68%), seguida de Megaptera novaeangliae (13%) y Tursiops truncatus (10%). La presencia de delfines moteados está relacionada con los cambios en la salinidad y la transparencia del agua, mientras que la de la ballena jorobada estaba relacionada con la altura de las olas (escala de Beaufort) y la temperatura del agua. Se confirmó la presencia de siete especies de cetáceos en dos zonas costeras del litoral Pacífico de Costa Rica, de las cuales tres están presentes durante todo el año. Se encontraron variables ambientales relacionadas con la presencia de al menos dos especies.
Impacto de la luz artificial sobre la anidación de la tortuga marina Dermochelys coriacea (Testudines: Dermochelyidae), en playa Cipara, Venezuela
(Universidad Nacional, Costa Rica., 2009) Rondón Médicci, María; Buitrago, Joaquín; Mccoy, Michael
Se comparó el número de nidos de tortuga laúd y su distribución espacial entre años con y sin luz artificial, y entre segmentos de playa oscuros e iluminados, en Playa Cipara, Península de Paria, Venezuela. Se entrevistó a los residentes para identificar sus percepciones sobre el impacto de la luz artificial en las tortugas marinas. El volumen medio de arena por metro de playa fue mayor en La Peña, Cipara y La Remate y menor en Varadero (p<0,001), aumentando de abril a junio y disminuyendo posteriormente hasta agosto (p<0,05). El porcentaje medio de grava fue mayor en Varadero y La Peña, y menor en La Remate y Cipara. La mayoría de los entrevistados afirmaron que la luz artificial no afecta a las tortugas marinas. Entre 2000 y 2005 se observaron 1.217 desembarcos de tortugas laúd y 1.056 nidos. Los nidos con éxito aumentaron con los años (p=0,035), así como el número total de nidos (p=0,015). De 2000 a 2003 hubo 743 desembarcos, 661 nidos y 374 puestas. Durante los dos años con luz eléctrica (2004-2005), hubo 474 desembarques, 395 nidos y 232 puestas. La proporción de desembarques con construcción de nidos disminuyó significativamente durante los años con luz eléctrica (p= 0,005), pero el éxito de nidificación no varió (p= 0,402). No se encontraron diferencias significativas entre los desembarcos por metro de playa en los sectores oscuros e iluminados (p=0,244), entre los nidos construidos (p=0,379) y en la tasa de éxito de nidificación (p=0,516). Los sectores oscuros e iluminados no difirieron en la proporción de desembarcos con nidos construidos (p=0,067) ni en la tasa de éxito (p=0,833).
Immobilization of free-ranging Hoffmann´s two-toed and brown-throated three-toed sloths using ketamine and medetomidine: a comparasion of physiologic parameters
(Universidad Nacional, Costa Rica., 2008) Hanley, Christopher S.; Siudak-Campfield, Joanna; Paul-Murphy, Joanne; Vaughan, Christopher; Ramírez, Oscar; Keuler, Nicholas S.; Sladky, Kurt K.
Free-ranging Hoffmann’s two-toed sloths (Choloepus hoffmanni; n526) and brown throated three-toed sloths (Bradypus variegatus; n515) were manually captured and immobilized with 2.5 mg/kg ketamine + 0.02 mg/kg medetomidine administered intramuscularly. Physical examinations were conducted on each sloth 10 min after initial injection, and blood, fecal, and ectoparasite samples were collected. Heart rate, respiratory rate, body temperature, indirect systolic blood pressure, and indirect peripheral oxygen saturation were monitored every 5 min for the duration of anesthesia. After 45 min, atipamazole (0.1 mg/kg) was administered intramuscu larly, as an antagonist to medetomidine, in order to facilitate recovery. All recoveries were smooth, rapid, and uneventful. Physiologic parameters were compared across time, gender, and species. All sloths, regardless of species and gender, demonstrated a time-dependent decrease in heart rate and blood pressure, and an increase in respiratory rate, during the course of anesthesia. Peripheral oxygen saturation was similar for all sloths over time. There were significant species differences for heart rate (Choloepus . Bradypus), respiratory rate (Choloepus . Bradypus), and systolic blood pressure (Bradypus . Choloepus), while there were significant gender differences for body temperature (males . females) and blood pressure (males . females). Results of this study suggest that the ketamine–medetomidine mixture, as described above, is a safe and effective anesthetic combination in free-ranging two- and three-toed sloths, although peripheral blood pressure should be monitored during anesthesia.
Ámbito de acción, uso del hábitat y actividad diaria de la taltuza Orthogeomys heterodus (Rodentia: Geomyidae) en una zona hortícola de Costa Rica.
(Universidad Nacional, Costa Rica., 1994) Bonillo, Never
Home range, daily activity and habitat use of four Giant Pocket Gophers Orthogeomys heterodus were detennined by radiotelemetry. The study was carried out in a horticultural area of Cartago province, Costa Rica, during December 1989 and January 1990. Home range averaged 325 m2 for males and 233 m2 for females. There was a significant relationship between home range size and individual body mass. In average, 78 % of localizations were in the nest or refuge located in all cases in the border of crops. Activity was greatest from 0600 to 0800 h and 1200 to 1400 h, and was reduced at night.
Home Range, Habitat Use, and Activity of Baird’s Tapir in Costa Rica
(Universidad Nacional, Costa Rica., 2002) Foerster, Charles R.; Vaughan, Christopher
Home range size, habitat utilization, and activity patterns of five adult Baird’s tapirs (Tapirus bairdii) were studied via radiotelemetry from June 1995 to May 1996 in Corcovado National Park, Costa Rica. Estimates of 4153 animal locations were made. Home range sizes (95% minimum convex polygon) for the entire study period (wet season and dry season) averaged 125.0 ha (SD 5 72.7), 94.9 ha (SD 5 47.6), and 96.8 ha (SD 5 51.2), respectively. Monthly home range sizes averaged 55.5 ha (SD 5 32.1) and did not vary between seasons. Across the entire study, secondary forest, the most commonly used habitat type (61.3%) was utilized more than expected as predicted by availability (49.6%), while the second most used habitat, primary forest, was used (25.0%) less than expected (36.2%). The same general habitat selection pattern was observed in the dry season. Wet season habitat utilization values showed tapirs using both primary and secondary forest habitats in proportion to their availability. Diurnal and nocturnal activity levels were estimated at 20.2 and 80.4 percent, respectively. More diurnal and less nocturnal activity was observed during the wet season compared to the dry season.

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