Artículos científicos

URI permanente para esta colecciónhttp://10.0.96.45:4000/handle/11056/14821

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Mostrando 1 - 4 de 4

Composición, diversidad y abundancia de peces en el embalse Arenal, Guanacaste, Costa Rica
(Universidad de Costa Rica (Costa Rica), 1989-11-01) Ulloa Rojas, Juan B.; Cabrera Peña, Jorge; Mora Jamett, Margarita
The abundance, species diversity. richneiS, dominance, evenness and similarity índices of the fish cornmunities at two stations in the Arenal Reservoir, Guanacaste, Costa Rica, were estimated between April 1984 and April 1985. Melaniris chagresi and Poecilia gillii were the most abundant species, with 86.93 %and 6.11% of total captured fishes (15,941). The Shannon-weaver diversity index was 0.32 for the Sangregado station and 0.31 for the Campamento station. There were not significant differences in indices between the two stations.
Distribución y abundancia de Caiman crocodilus en el Refugio Nacional de Vida Silvestre Caño Negro, Costa Rica
(Revista de Biología Tropical vol.51 no.2 571-578 2003, 2003) Cabrera Peña, Jorge; Protti Quesada, Maurizio; Urriola Hernández, Mario; Cubero Murillo, Rolando
The distribution and abundance of a population of Caiman crocodilus fuscus were estimated by monthly counting of eyeshines at night, from February 1999 to March 2000 in six transects of Río Frío in the Caño Negro National Refuge (RNVSCN), Northern Costa Rica. March was the month with the greatest abundance of caimans observed. The visible fraction of the population (PV2 index) fluctuated between 42.59 % to 54.71 % during the wet season and 35.49 % to 53.93 % in the dry season. The transects of river with greater abundance of caimans were Terrón-Sabogal and Sabogal-Playuela. Significant differences were determined in the abundance of caimans between transects, except the transects Entrada San Sebastían-Las Cubas and Las Cubas-Entrada Caño Los Patos and Entrada Caño Los Patos-Terrón and Boca Sabogal-Playuela. The population of estimated brown caiman in this study was 2283.48 ± 313.5. The statistical analysis by seasons did not show significant differences in the number of caimans observed. Estimated mean number of caimans per km of river was 74.36 /km for 30.7 km of habitat. The results of this study indicated that the fluctuation in population density during the seasons is attributable to local movements.
Estructura espacial y temporal de la ictiofauna del Estero de Tamarindo, Parque Nacional Marino Las Baulas, Costa Rica
(Universidad Nacional (Costa Rica), 2018-04-01) Ortiz-Araya, Scarleth; Chacón Guzmán, Jonathan; Víquez-Portugués, Rigoberto; Sibaja-Codero, Jeffrey
Spatial and temporal structure of the ichthyofauna of the Estuary of Tamarindo, Las Baulas National Marine Park, Costa Rica. Fish communities in mangrove areas have an ecological and socio-economic importance. The management in this kind of habitat is based on the data information about spatial and temporal patterns. The main goal of the study is determinate the spatial and temporal structure of the ichthic community from Tamarindo mangrove area. Six samplings trips were conducted from August 2009 to June 2010, at five mangrove stations using four different fishing gear. Also, environmental variates were recording (temperature, oxygen, salinity, pH, and water transparency). A total of 1357 individuals belonging to 59 species of 28 families were identified. Carangidae and Lutjanidae were more richness families, and the most abundant were Poecilidae, Mugilidae and Clupeidae. Poeciliopsis elongata was the most abundant species. Temporally, the diversity reached a minimum of 1.55 in December and a maximum of 1.96 in April. The richness presented a minimum of 22 species in February and a maximum of 25 in December. Spatially, the diversity reached a minimum of 1.96 in the mouth of the estuary and a maximum of 2.79 in mid estuary; the richness a minimum of 24 species inner the estuary and a maximum of 30 at mid estuary. Additionally, a temporal pattern of succession of species was determined. The fish community shows change in the similarity in their species composition from the mouth to the inner part of the estuary. At inner of the estuary the abundance was low, in contrast with the richness, diversity and equitability. Finally, nursery process for some key species for fisheries occurs in this estuary; made it fragile and susceptible to pollution and anthropogenic impacts, because their short mangrove area and shallow depth.
Nematode assemblages in four ecosystems of Parque Nacional del Agua, Costa Rica
(Elsevier (Países Bajos), 2022) Varela-Benavides, Ingrid; Abolafia, Joaquín; Guevara-Mora, Meyer; Peña Santiago, Reyes; Ferris, Howard
The soil nematode fauna of five locations situated in Parque Nacional del Agua (PNA) in Costa Rica is characterized and analyzed. Four ecosystems were sampled in each location: primary (undisturbed) forest, secondary (naturally regenerated) forests, tree plantations (cleared and replanted with timber trees), and pastures (cleared of trees). Five soil samples of 100 g were analyzed in each location and ecosystem, resulting in a total of 100 samples. One hundred and thirty-one nematode genera were identified, and their abundance and biomass were estimated and analyzed by means of nonmetric multidimensional scaling (NMDS) and redundancy analysis (RDA). The observed nematode abundance was 1237 ± 520 specimens per soil sample for the whole survey, similar to previously reported from tropical soils. Dominance-diversity curves, based on nematode abundance, follow a similar ‘hollow curve’ pattern, with only 20 of the genera representing 84.6% of the total abundance, and only 12 of the genera representing 88% of the total biomass. Helicotylenchus, tylenchids, criconematids, Belondira, Longidorus, Xiphinema, Monotrichodorus, Prismatolaimus and Steinernema are important in the assemblages due their abundance or biomass in the different samples. Monotrichodorus and Discocriconemella appear related to undisturbed ecosystems, and they could have potential as disturbance indicators. Biomass-based dominance-diversity curves have similar qualitative and quantitative behavior to those observed in abundance distribution, but the dorylaims, Aporcelinus and Aporcelaimoides, which represented only the 0.35% of the abundance, having a major part of the total biomass (4.33%). NMDS analysis segregated locations into two groups, sampled sites were arranged according to the life zone where they belong. Ecosystems were segregated into natural ecosystems and plantations but having overlapping zones. Whereas RDA analysis indicated that organic matter and Cu are the most relevant edaphic variables for explaining the distribution of nematode assemblages, however few genera appear important in the ordination, Mesocriconema, Longidorus, Xiphinema and Belondira between them.

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