Biología

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https://hdl.handle.net/10669/273

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Mostrando 1 - 6 de 6

Comparing the efficiency of monofilament and traditional nets for capturing bats
(2021) Chaves Ramírez, Silvia; Castillo Salazar, Cristian; Sánchez Chavarría, Mariela; Solís Hernández, Hellen; Chaverri Echandi, Gloriana
Traditional mist nets used for capturing bats have several drawbacks, particularly that they are inefficient at sampling many insectivorous species. One possible alternative is to use monofilament nets, whose netting is made of single strands of yarn instead of several as regular nets, making them less detectable. To date, no study has quantified the capture efficiency of monofilament nets compared to regular mist nets for the study of bats. Here we compare capture efficiency of monofilament and regular mist nets, focusing on bat abundance and species diversity at a lowland tropical forest in southwestern Costa Rica. During our sampling period, we captured 90 individuals and 14 species in regular nets and 125 individuals and 20 species in monofilament nets. The use of monofilament nets increased overall capture rates, but most notably for insectivorous species. Species accumulation curves indicate that samples based on regular nets are significantly underestimating species diversity, most notably as these nets fail at sampling rare species. We show that incorporating monofilament nets into bat studies offers an opportunity to expand records of different guilds and rare bat species and to improve our understanding of poorly-known bat assemblages while using a popular, relatively cheap and portable sampling method.
Diversity of deep-sea echinoderms from Costa Rica
(2022-07-31) Alvarado Barrientos, Juan José; Chacón Monge, José Leonardo; Azofeifa Solano, Juan Carlos; Cortés Núñez, Jorge
Echinoderms are a highly diverse group and one of the most conspicuous in the deep sea, playing ecological key roles. We present a review about the history of expeditions and studies on deep-sea echinoderms in Costa Rica, including an updated list of species. We used literature and information gathered from the databases of the California Academy of Sciences, the Benthic Invertebrate Collection of the Scripps Institution of Oceanography, the National Museum of Natural History, the Museum of Comparative Zoology and the Museo de Zoología from the Universidad de Costa Rica. A total of 124 taxa (76 confirmed species) have been collected from the Costa Rican deep sea, 112 found in the Pacific Ocean, 13 in the Caribbean Sea, and one species shared between the two basins. We report 22 new records for the Eastern Tropical Pacific, 46 for Central American waters, and 58 for Costa Rica. The most specious group was Ophiuroidea with 37 taxa, followed by Holothuroidea (34 taxa), Asteroidea (23 taxa), Echinoidea (17 taxa), and Crinoidea (11 taxa). The highest number of species (64) was found between 800 m and 1200 m depth. Only two species were found deeper than 3200 m. Further efforts on identification will be required for a better comprehension of the diversity of deep-sea echinoderms. Limited research has been done regarding the biology and ecology of deep-sea echinoderms in Costa Rica, so additional approaches will be necessary to understand their ecological functions.
Plant diversity in the diet of Costa Rican primates in contrasting habitats: a meta-analysis
(2023) Chaves Badilla, Oscar Mauricio; Morales Cerdas, Vanessa; Calderón Quirós, Jazmín; Azofeifa Rojas, Inés; Riba Hernández, José Pablo; Solano Rojas, Daniela; Chaves Cordero, Catalina; Chacón Madrigal, Eduardo; Melin, Amanda D.
In human-modified tropical landscapes, the survival of arboreal vertebrates, particularly primates, depends on their plant dietary diversity. Here, we assessed diversity of plants included in the diet of Costa Rican non-human primates, CR-NHP (i.e. Alouatta palliata palliata, Ateles geoffroyi, Cebus imitator, and Saimiri oerstedii) inhabiting different habitat types across the country. Specifically, we assessed by analyzing 37 published and unpublished datasets: (i) richness and dietary -plant diversity, (ii) the β-diversity of dietary plant species and the relative importance of plant species turnover and nestedness contributing to these patterns, and (iii) the main ecological drivers of the observed patterns in dietary plant . Diet data were available for 33 Alouatta, 15 Cebus, 8 Ateles, and 5 Saimiri groups. Overall dietary plant species richness was higher in Alouatta (454 spp.), followed by Ateles (329 spp.), Cebus (237 spp.), and Saimiri (183 spp.). However, rarefaction curves showed that -diversity of plant species was higher in Ateles than in the other three primate species. The γ-diversity of plants was 868 species (range=1664-2041 species). The three most frequently reported food species for all CR-NHP were Spondias mombin, Bursera simaruba, and Samanea saman. In general, plant species turnover, rather than nestedness, explainedthe dissimilarity in plant diet diversity (βsim = 0.76) of CR_NHP. Finally, primate species, habitat type (life zone and disturbance level) and, to a lesser degree, sampling effort were the best predictors of the dietary plant assemblages. Our findings suggest that CR-NHPdiets were diverse, even in severely-disturbed habitats.
Pocillopora spp. growth analysis on restoration structures in an Eastern Tropical Pacific upwelling area
(2022) Combilet, Lisa; Fabregat Malé, Sònia; Marín Moraga, José Andrés; Gutiérrez, Mónica; Alvarado Barrientos, Juan José
Coral reefs in Culebra Bay (North Pacific of Costa Rica) are threatened by multiple anthropogenic disturbances including global warming, overfishing, eutrophication, and invasive species outbreaks. It is possible to assist their recovery by implementing ecological restoration techniques. This study used artificial hexagonal steel structures, called “spiders” to compare growth of Pocillopora spp. coral fragments of different sizes. Three initial fragment class sizes 30 were used: 2, 5 and 8 cm, with each class size having 42 initial fragments. Changes in fragment 31 length, width and area were measured monthly from January to December 2020. Results showed an overall survivorship of 70%, and no significant differences in survivorship and linear growth 33 rate were detected between class sizes. The linear growth rates are 4.49 ± 1.19 cm yr-1, 5.35 ± 34 1.48 cm yr-1 and 3.25 ± 2.22 cm yr-1 for the 2, 5 and 8 cm initial class sizes, respectively. Results do not show significant differences in growth rates between the different initial fragment sizes. However, since small fragments (2 cm) presented higher mortality during the first month, using larger fragments is recommended. In addition, coral fragments grew 48% more during the non-upwelling season, which may suggest that it might be more effective and safer to start the restoration efforts during this period.
Redox stress reshapes carbon fluxes of Pseudomonas putida for cytosolic glucose oxidation and NADPH generation
(2020) Nikel Mayer, Pablo Iván; Fuhrer, Tobias; Chavarría Vargas, Max; Sánchez Pascuala, Alberto; Sauer, Uwe; de Lorenzo, Víctor
The soil bacterium and metabolic engineering platform Pseudomonas putida tolerates high levels of endogenous and exogenous oxidative stress, yet the ultimate reason of such property remains unknown. To shed light on this question, NADPH generation routes—the metabolic currency that fuels redox stress responses—were assessed when P. putida KT2440 was challenged with H2O2 as proxy of oxidative conditions. 13C-tracer experiments, metabolomics and flux analysis, together with inspection of physiological parameters and measurement of enzymatic activities, revealed a substantial flux reconfiguration under oxidative stress. In particular, periplasmic glucose processing was rerouted to cytoplasmic oxidation, and cyclic operation of the pentose phosphate pathway led to significant NADPH fluxes, exceeding biosynthetic demands by ~50%. This NADPH surplus, in turn, fuelled the glutathione system for H2O2 reduction. These properties not only contribute to the tolerance of P. putida to environmental stresses, but they also highlight the value of this host for harsh biotransformations.
The effect of noise variation over time and between populations on the fine spectrotemporal characteristics of different vocalization types
(2021-01) Méndez Vázquez, Carolina; Barrantes Montero, Gilbert; Sandoval Vargas, Luis Andrés
Noise affects the recognition of acoustic signals by masking information. To compensate for increased noise, individuals often increase the minimum frequency of their vocalization to reduce noise interference. Our goal was to analyze the effect of noise on the characteristics of different bird vocalizations, through a comparative study of vocalizations on the same bird species. We analyzed the effects of noise variation on the fine spectrotemporal characteristics of calls, songs, and duets of White-eared Ground-sparrows (Melozone leucotis) across three populations over a three-year period. We recorded vocalizations and noise levels simultaneously from 41 territories between 2012 and 2014. We measured the duration, minimum, maximum, and maximum amplitude frequency, and counted the number of songs elements for each vocalization recorded. As we predicted, noise influences the minimum frequency of song, but did not have an effect on the fine spectrotemporal characteristics for calls and duets. We did, however, find that low and high frequency of calls and duets increased with noisepopulation-year interaction. Our results suggest that differences in noise values at each population were inadequate to observe changes in vocalization characteristics. In conclusion, evaluating responses to different noise levels on different vocalization types for the same species expands our understanding of the flexibility of birds to adjust vocalizations in response to anthropogenic noise.

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