Papers by Biología Tropical
The Gorean snapper, Lutjanus goreensis is an important component of artisanal fisheries and trawl... more The Gorean snapper, Lutjanus goreensis is an important component of artisanal fisheries and trawl landings in the Gulf of Guinea. Despite its economic importance, there is a dearth of information on size structure and life history strategies of the species. Therefore, the objectives of this study were to provide baseline data on the life stages, exploitation status and habitat use for the species in Nigeria. Monthly samples were obtained from artisanal and trawl catches in Five Cowrie Creek and Lagos coastal waters between December 2008 and December 2010, respectively. Length-frequency distributions of the fishes caught were analysed to provide preliminary information on mean and modal lengths at capture and life-history strategies based on habitat use and estuarine-dependency for L. goreensis. A total of 822 specimens of L. goreensis were collected from Five Cowrie Creek while 377 specimens were collected from Lagos coastal waters. Total length varied between 7.90-34.90cm for creek samples and from 21.90-56.10cm for marine samples. Length-frequency histograms showed polymo-dal size distributions in creek and marine samples. Length-frequency distributions of L. goreensis showed a high abundance of juveniles (<20cm) and sub-adults (20-35cm) which accounted for 84.1% and 68.4% of creek and marine samples examined, respectively. For the creek samples, fish in modal length class of 13.00-13.99cm were the most exploited while in the marine samples, length classes of 29.00-30.99cm and 31.00-32.99cm constituted the most frequently exploited fishes. Increase in total lengths from the creek (mean±SD; 16.19±3.73cm) to the marine habitat samples (32.89±6.14cm) indicated ontogenetic shift in habitat use. Occurrence of a predominant juvenile population in Five Cowrie Creek by L. goreensis suggests estuarine-dependency and is indicative of a temporary juvenile habitat or a migratory corridor. In conclusion, data from the presently reported study and previous studies demonstrated that juvenile L. goreensis displays estuarine dependency and habitat flexibility. Hence, this underscores the importance of preserving estuarine environments as essential fish habitats to prevent overfishing. The study also concludes that the species is vulnerable to recruitment overfishing in the marine environment especially as a consequence of shrimping. Consequently, it advocates for ban on all fishing activities during peak spawning periods in breeding grounds and shrimp ground assemblage. Rev. Biol. Trop. 63 (1): 199-212. Epub 2015 March 01.
Growth and mortality parameters of Orthopristis ruber (Perciformes: Haemulidae) from Los Frailes ... more Growth and mortality parameters of Orthopristis ruber (Perciformes: Haemulidae) from Los Frailes Archipelago, Venezuela. Orthopristis ruber is a species in high demand in Eastern Venezuela, but production has been decreasing in recent years. For this reason, our objective was to estimate the growth and mortality parameters of this resource. Monthly samples were collected from June 2011 to May 2012, obtaining 2 980 specimens in El Tirano and Puerto Abajo. Data on total length (cm), total weight (g), and sex were recorded for each specimen. No sexual dimorphism was shown with respect to length (t s =1.113, p>0.05), so one length-weight ratio was established for both sexes (Wt=0.0612*Lt 2.54); and they both exhibited minor allo-metric growth. Growth was estimated by analysis of length frequency distributions using FiSAT software. The estimated growth parameters (L ∞ =39.03cm, W ∞ =679.60g, k=0.48/year and t o =-0.32year) showed moderately rapid growth. Length frequency data were adjusted to the von Bertalanffy model, and indicated an exponential tendency of accelerated growth during the first years of life, followed by slow growth until the fish reached its maximum length. The coefficient of variation of the growth index (Ø') demonstrated no differences in growth pattern. The natural mortality rate (M=0.97/year), from fishing (F=1.57/year), and total mortality (Z=2.54/year), were high, as well as the exploitation rate (E=0.62/year). We concluded that O. ruber has been fully exploited by artisanal fishers, and suggest a continuous study on population dynamics, to recommend optimum management techniques for the fishery. Rev. Biol. Trop. 63 (1): 189-198. Epub 2015 March 01.
Barilius bendelisis, commonly known as Indian Hill Trout is an upland water fish of South East As... more Barilius bendelisis, commonly known as Indian Hill Trout is an upland water fish of South East Asia. It belongs to the family Cyprinidae and dwells in shallow, clear and cold water. In this study, the intraspecific variation of Barilius bendelisis, on the basis of morphometric characters, was investigated. Altogether, 402 specimens were collected from four rivers in the Central Indian Himalaya. A truss network was constructed by interconnecting 12 landmarks to yield 30 distance variables that were extracted from digital images of specimens using tpsDig2 and PAST software. Allometric transformed truss measurements were subjected to univariate analysis of variance, factor analysis and discriminant analysis. All variables exhibited significant differences between the populations. Altogether 88% of the specimens were classified into their original populations (81.98% under a 'leave-one-out' procedure). With factor analysis measurements of the head region, the middle portion and the caudal region had high loadings on the first and second axis. The results indicated that B. bendelisis has significant phenotypic heterogeneity between the geographically isolated regions of Central Indian Himalaya. We hypothesize that the marked interspecific variation in B. bendelisis is the result of local ecological conditions. Rev. Biol. Trop. 63 (1): 165-173. Epub 2015 March 01.
Growth stanzas or abrupt changes in growth rates are present throughout the life span of fish. Id... more Growth stanzas or abrupt changes in growth rates are present throughout the life span of fish. Identifying growth stanzas will help to adequately described growth taking into account that fishes are indeterminate growers. In this study, we used length-weight (L-W) relationships to analyze the growth stanzas in the Grouper-Snapper complex of Southern Gulf of Mexico. For this, the type of sexuality, sex and different sexual maturity phase were considered in the analyses of three species of gonochoric Snappers (Lutjanidae) and six species of protogynous hermaphrodite Groupers (Epinephelidae). Welch ANOvA tests were carried out to determine the existence of differences in length and weight between juveniles and adults per sex. According to the observed differences, L-W relationship parameters (a and b), standard error (SE b) and coefficients of determination (R 2) were calculated for all species separately by sex and sexual maturity phase. Snappers' juvenile-females b-value ranged from 2.44-2.77, juvenile-males from 2.16-2.94, adult-females from 2.63-2.80 and adult-males from 2.63-2.98. Groupers' b-value ranged for juvenile-females 2.66-3.20, adult-females from 2.73-3.31 and for adult-males 2.93-3.29. For each relationship b-value was t-tested (t-Student) to explore differences from the allometric coefficient (b=3), which indicated changes in body form. Hypothesis test, for regression slopes (b) between Snappers' juvenile-females vs. adult-females and juvenile-males vs. adult-males and Groupers' juvenile-females vs. adult-females and adult-females vs. adult-males, indicated different growth stanzas related to gonadal development for Snappers, and to gonadal development and sex change in Groupers. The identification of growth stanzas is crucial to avoid an overestimation or misleading growth rate which is used in fisheries management to establish some target reference points, such as maximum sustainable yield or yield-per-recruit. Rev. Biol. Trop. 63 (1): 175-187. Epub 2015 March 01
Osteological development of the vertebral column and caudal complex of Lutjanus guttatus (Percifo... more Osteological development of the vertebral column and caudal complex of Lutjanus guttatus (Perciformes: Lutjanidae) larvae under rearing conditions. The spotted rose snapper (Lutjanus guttatus) is an important commercial species in Mexico with good culture potential. The osteological study at early stages in this species is an important tool to confirm normal bone structure and for the detection of malformations that may occur during early development. This study was carried out in order to evaluate and describe the normal osteological development of the vertebral column and caudal complex of this species grown under controlled conditions. For this, a total of 540 larvae of L. guttatus, between 2.1 and 17.5mm of total length (TL), were cultured during 36 days; culture conditions were 28ºC, 5.74mg/L oxygen and 32.2ups salinity with standard feeding rates. To detect growth changes, a sample of 15 organisms was daily taken from day one until day 36 of post-hatch (DPH). Samples were processed following standard techniques of clearing, and cartilage (alcian blue) and bone staining (alizarin red). Results showed that the vertebral column is composed of ten vertebrae in the abdominal region, and 14 vertebrae including the urostyle in the caudal region. The development of the axial skeleton starts with the neural arches and haemal arches at 3.8mm TL. Caudal elements such as the hypurals and parahypural began to develop at 4.1mm TL. Pre-flexion and flexion of the notochord and the formation of all hypurals were observed between 5.3 and 5.8mm TL. Ossification of the vertebrae in the abdominal region and in some neural arches initiated at 9.5mm TL. In the caudal region, all the neural and haemal arches ossified at 10.2mm TL. All the abdominal vertebrae and their respective neural arches and parapophyses ossified at 11.2mm TL, while the elements of the caudal complex that ossified were the hypurals, parahypurals and modified haemal spines. All caudal fin rays, 12 neural spines and 3 haemal arches were ossified by 15.5mm. The complete ossi-fication process of this specie under laboratory culture conditions was observed when larvae reached 17.3mm TL on 36 DPH. Detailed analysis of the osteological structures will allow a reference description to evaluate and detect malformations that may occur during the larval culture of the spotted rose snapper. Rev. Biol. Trop. 63 (1): 155-164. Epub 2015 March 01.
Estimation of the sampling cover for dung beetles (Coleoptera: Scarabaeinae) in Colombia. The pro... more Estimation of the sampling cover for dung beetles (Coleoptera: Scarabaeinae) in Colombia. The promotion of biodiversity conservation strategies must address the lack of information and the difficulty of identifying knowledge gaps that may facilitate our knowledge of different taxonomic groups. Dung beetles constitute one of those groups, despite having been proposed as an efficient bioindicator of environmental disturbance processes. In this work, we aimed to prepare a diagnosis on the state of knowledge of the subfamily Scarabaeinae, focusing on the cover sampling degree of this group in Colombia, with the purpose of identifying high-priority areas that will allow the completion of a national inventory. The work consisted of a bibliographical compilation using 12 referential databases and the examination of specimens deposited in 26 national collections. A total of 16 940 individuals were examined, finding registers for 232 species from 386 localities. The respective distribution cover maps were presented, and the cover at a national level was 10.62%. A historical analysis demonstrated a proliferation in the number of studies for the last three decades; nevertheless, a great proportion of unpublished works persists, resulting in only 64 sampled localities with published records. The localities with the greatest sampling efforts were RN La Planada, Lloro, AUN Los Estoraques, PNN Tinigua and Mariquita. Registries for all departments were available, and the best sampled ones were Cundinamarca, Antioquia, Valle del Cauca and Boyaca. The ecosystems with the greatest number of publications are the Andean pre mountain humid forest, followed by the Andean mountain humid forest and the Pacific humid forest. Other ecosystems with few studies included mangroves, desert zones, natural savannahs, palm swamps, paramos, flooding forests and agroforestry systems. The biogeographic region with the greatest number of localities was the Andean region, followed by Choco-Magdalenense and Amazonia. Our results showed that high levels of subsampling persist and that some zones lack registries, as in the case of some parks of the national system of protected areas. It is imperative that the sampling cover is extended at a national level, focusing all possible efforts on collecting in those subsampled regions that have high conservation importance, with the main goal of completing the listing of species and their distribution. Rev. Biol. Trop. 63 (1): 97-125. Epub 2015 March 01.
The Neotropical region exhibits the largest diversity of fish worldwide; however, little is known... more The Neotropical region exhibits the largest diversity of fish worldwide; however, little is known about the early development of fish species from this region. Therefore, to contribute to this knowledge, this study aimed to morphologically describe the early stages of development (eggs, larvae and juveniles) of S. pappaterra using morphometric and meristic traits, and to assess changes in growth rates throughout larval and juvenile development by analyzing the relationships between various morphometric traits using analytical regression models. Both juvenile and adult individuals with mouth-brooded offspring were collected along the basins of the Cuiabá and Manso Rivers in the state of Mato Grosso, Brazil between March 2000 and March 2004. After the adults were identified, the offspring were classified according to its stage (embryonic, larval or juvenile period), and various morphometric and meristic variables were individually measured (when possible). The eggs of this species are yellow in color, oval shaped, show dendritic pigmentation within their yolk, have small to moderately sized perivitelline spaces and lack a mucous membrane and oil droplets. The horizontal and vertical diameters of the sample yolks ranged from 1.43mm to 2.70mm and 1.05mm to 1.68mm, respectively. The standard length of the larval period varied from 4.30mm to 7.16mm, and the standard length of the juvenile period varied from 10.29mm to 24.57mm. Larvae exhibit yolk sacs with internal dendritic pigmentation and dark punctate pigmentation in the dorsal and ventral body regions, whereas irregular transverse spots along the flanks are observed during the juvenile period. Adhesive organs are only present during the yolk-sac stage and at the beginning of the flexion stage. The mouth is terminal during all stages of development. The myomere number varied from 22 to 29 (9 to 16 pre-anal and 10 to 16 post-anal), and the maximal numbers of fin rays and spines were as follows: dorsal, xvI+10; anal, Iv+8; pectoral, 16; and pelvic, I+8. Growth analyses identified periods of important change in larval morphology (i.e., metamorphosis), particularly during the flexion and post-flexion stages and in juveniles. Therefore, the morphological development of S. pappaterra is consistent with the ecological requirements of this species, which primarily occurs in structured lentic environments with aquatic macrophytes. Rev. Biol. Trop. 63 (1): 139-153. Epub 2015 March 01.
Biomass of Cornops aquaticum (Orthoptera: Acrididae) in wetlands of Northeast Argentina. The esti... more Biomass of Cornops aquaticum (Orthoptera: Acrididae) in wetlands of Northeast Argentina. The estimation of biomass in insect populations is a key factor to quantify the available resources and energy fluxes in ecosystems food webs. Cornops aquaticum is a common herbivore in Eichhornia plants in wetlands of Northeast Argentina. We aimed to analyse its biomass variation, related to the different grasshopper age categories populations in two host-plants: Eichhornia azurea and Eichhornia crassipes. For this, standard samplings of C. aquaticum populations were carried out with an entomological net of 70cm diameter in two wetlands with E. azurea and E. crassipes, in Corrientes and Chaco Provinces; besides, dry weight was also obtained (directly and indirectly), and a regression model to indirectly estimate the biomass from a linear dimension measure (hind femur length) is proposed. A total of 2 307 individuals were collected and separated in different age categories; their abundance and linear dimension data were obtained. The model proposed was lnDM=lna+b*lnH (where DM=dry mass, a and b are constants and H=hind femur length) (R 2 =0.97). The population biomass variations of C. aquaticum were due to the relative abundance of each age category and the grasshopper individual dry weight. No significant differences were found between populations biomasses obtained by direct and indirect methods in E. azurea and E. crassipes floating meadows. This model made easier the C. aquaticum biomass calculation for both individuals and the population, and accelerated the processing of high number of samples. Finally, high biomass values of populations and individual age category (especially in adults) emphasize the importance of C. aquaticum as a consumer and a resource for predators on Eichhornia floating meadows food webs. Rev. Biol. Trop. 63 (1): 127-138. Epub 2015 March 01.
The toxicity induced by insecticides in aquatic organisms is of utmost relevance because it may g... more The toxicity induced by insecticides in aquatic organisms is of utmost relevance because it may give a clue about the degree of health or damage of the involved ecosystem. In the present report, we determined the effect of dieldrin (DD) and chlorpyrifos (CP) on the freshwater crayfish, Cambarellus montezumae. The organisms (4-6cm in diameter) were collected in the Ignacio Ramírez Reservoir, situated at 50km Northeast of Mexico City, in the Rio Lerma Basin. Initially, we determined the LC 50 value with the Probit method, then the DNA damage with single cell gel electrophoresis (comet assay applied at 24, 48, and 72h of exposure) to the brain and hepatopancreas of animals exposed (in reconstituted water) to 0.05 and 0.5mg/L of each insecticide. In the hepatopancreas of the same organisms, we determined the lipid peroxidation by applying the TBARS test. DNA damage and lipid peroxidation were also evaluated with the same methods to organisms exposed in water from the reservoir. In regard to the LC 50, at 72h of exposure, we found a value of 5.1mg/L and a value of 5.62mg/L for DD and CP, respectively. The comet assay applied at different exposure times showed significant DNA damage to both organs, with respect to the control level. In the case of DD, statistical significance was observed for the two doses in the whole evaluated schedule. CP was genotoxic in the brain with the high dose at 72h, and in the hepatopancreas with the two tested doses at all evaluated exposure times. Also, a significant lipid peroxidation increase was detected with the two doses of insecticides. In the study with water from the reservoir, a more pronounced DNA damage was detected. Our results showed strong DNA damage induced by both insecticides in the crayfish, as well as a correlation with the lipid peroxidation effect, suggesting that oxida-tive stress is involved in the genotoxic alteration. Our results also showed the usefulness of the studied organism as well as the applied tests for the evaluation of toxicological effects, and suggested the pertinence of applying the comet assay to other freshwater organisms to evaluate the bioaccumulation of insecticides. Rev. Biol. Trop. 63 (1): 83-96. Epub 2015 March 01.
Contribution of tropical upland forests to carbon storage in Colombia. The tropical montane fores... more Contribution of tropical upland forests to carbon storage in Colombia. The tropical montane forests in the Colombian Andean region are located above 1 500m, and have been heavily deforested. Despite the general presumption that productivity and hence carbon stocks in these ecosystems are low, studies in this regard are scarce. This study aimed to i) to estimate Above Ground Biomass (AGB) in forests located in the South of the Colombian Andean region, ii) to identify the carbon storage potential of tropical montane forests dominated by the black oak Colombobalanus excelsa and to identify the relationship between AGB and altitude, and iii) to analyze the role of tropical mountain forests in conservation mechanisms such as Payment for Environmental Services (PES) and Reducing Emissions from Deforestation and Degradation (REDD+). Twenty six 0.25ha plots were randomly distributed in the forests and all trees with D≥10cm were measured. The results provided important elements for understanding the role of tropical montane forests as carbon sinks. The information produced can be used in subnational initiatives, which seek to mitigate or reduce the effects of deforestation through management or conservation of these ecosystems, like REDD+ or PES. The AGB and carbon stocks results obtained were similar to those reported for lowland tropical forests. These could be explained by the dominance and abundance of C. excelsa, which accounted for over 81% of AGB/carbon. The error associated with the estimates of AGB/carbon was 10.58%. We found a negative and significant relationship between AGB and altitude, but the higher AGB values were in middle altitudes (≈1 700-1 800m), where the environmental conditions could be favorable to their growth. The carbon storage potential of these forests was higher. However, if the historical rate of the deforestation in the study area continues, the gross emissions of CO 2 e to the atmosphere could turn these forests in to an important emissions source. Nowadays, it is clear that tropical montane forests are vulnerable to deforestation, especially black Oak forests due to their commercial value. Given their high carbon storage potential, the presence of endemic species and the strategic functions of these ecosystems, we recommend that they should be considered relevant during REDD+, PES or any other conservation assessment. Rev. Biol. Trop. 63 (1): 69-82. Epub 2015 March 01.
Animal-plant interactions in Neotropical forests are complex processes. Within these processes, m... more Animal-plant interactions in Neotropical forests are complex processes. Within these processes, mid-to large-sized mammals consume fruits and seeds from several species; however, because of their size these mammals are overhunted, resulting in defaunated forests. Our objective was to evaluate and compare seed removal and survivorship in a forest with no hunting, a forest with moderate or reduced hunting, and a forest with higher hunting pressure. We examined the interaction between Astrocaryum gratum and white lipped peccary (Tayassu pecari) to tease apart the defaunation process. To isolate and evaluate mammal seed removal rates and to identify the causes of mortality on A.gratum, under the three different hunting pressures forests, we used exclosures in each one. In four different forest-patches for each forest, we positioned a block-treatment consisting of three exclosures (total exclusion, peccary exclusion, and control), randomly distributed 5m apart and the block-treatments spaced 50-75m apart from one another. We established 15 treatments in total for each patch (5 blocks per patch). There were 20 blocks within each forest type. For total exclusion, all vertebrates were excluded using galvanized wire mesh exclosures. The second, the peccary exclusion, was designed to stop peccaries from entering treatment units, providing access only to small vertebrates; larger mammals were able to access the treatment unit by reaching over the sides and the open top; finally, the Control allowed full access for all mammals. Fresh A. gratum fruits were collected from the forest floor under different adult trees throughout the study area. In each exclosure treatment, twenty A.gratum seeds were placed, and their removal was recorded. In total, 3 600 seeds were analyzed. Seed survival was lower in unhunted forest compared to areas with moderate hunting and forest with a higher hunt pressure, supporting the hypothesis of the importance of mammals in seed removal. From the initial 400 seeds left for each control exclosure in each type of forest, there was a significant difference between the seed removal; 1.75% seeds in the unhunted forest remained; 43.5% in the moderately hunted forest, and 48.5% in hunted forest. The main cause of seed mortality was white lipped peccaries; while in the forests without them, the main removal was caused by rodents and a higher insect infection was observed in the heavily hunted forest. Our results indicated that defaunation affects seed survivorship. Rev. Biol. Trop. 63 (1): 57-67. Epub 2015 March 01.
Pollination ecology of three sympatric species of Oenocarpus (Arecaceae) in the Colombian Amazon.... more Pollination ecology of three sympatric species of Oenocarpus (Arecaceae) in the Colombian Amazon. The understanding of pollination mechanisms is vital for developing management and conservation actions of economically important species. In order to understand the pollination mechanisms of the promising palms in the genus Oenocarpus (Arecaceae), we studied floral morphology and biology, of three sympatric species in the Colombian Amazon: O. bataua, O. balickii and O. minor. During the period 2010-2012 we made direct and continuous observations of inflorescences (visitors, pollinators, and reproductive success) of the three species in every development phase. We determined the association of the palms with their floral visitors through a complex or interaction network, whereas specificity or preference of the insects for each individual palm was assessed through paired similarity analysis, similarity analysis (ANOSIM), and ordering analysis based on non-metric multidimensional scaling (NMSD). The three species flowered throughout the year; their inflorescences have long rachillae that hang close to each other from a short rachis, and they bear flowers in dyads or triads. Inflorescences are protandrous, thermogenic; anthesis takes place during daytime but pollination is nocturnal. We recorded 79 species of insects, mainly beetles, 33 of which visited O. balickii, 63 visited O. bataua, and 33 visited O. minor. Although they shared some visitors, their abundance during the pistillate phase, as well as their pollen loads showed that only a few species of Curculionidae and Nitidulidae are the principal pollinators of the three studied species. Differences in network structure between staminate and pistillate phases, as well as difference in abundance found with the ANOSIM and NMSD similarity tests, suggest a high specificity of pollinators, leading to reproductive isolation among the three species. Because all pollinating beetles were found to develop their life cycles within the inflorescences, we hypothesize the occurrence of a specialized system of mutual dependence between each of this three Oenocarpus species and their pollinators. This specialization assures a year-round availability of the pollinators. Rev. Biol. Trop. 63 (1): 35-55. Epub 2015 March 01.
Diagnosis for the ecological conservation of Jatropha spp. (Euphorbiaceae) and their habitats in ... more Diagnosis for the ecological conservation of Jatropha spp. (Euphorbiaceae) and their habitats in the Tehuacan-Cuicatlan Reserve, Mexico. Jatropha spp. is an important phytogenetic resource used as food, medicine, and biofuel. in this study, we verified the taxonomic identity of Jatropha species for The Biosphere Reserve Tehuacan-Cuicatlan, and the Ecological Land Units (ELU) occupied by them. We assessed the conservation status of their habitats, and the vulnerability of Jatropha spp. populations. A total of 15 sampling sites were selected in the Reserve. The taxonomic work was based on specimens, original descriptions and type material from herbaria and those available on-line. ELUs were classified using biophysical variables, and gvSiG software. Ecological attributes were determined using a quantitative analysis by the point-centered quarter method; disturbance was estimated through site indicators, and the conservation status of the Jatropha populations was assessed using the Method for Evaluation of the Risk of Extinction of Plants in Mexico (MER). Jatropha frequently dominated the physiognomy of plant communities. The current distribution of Jatropha species in the Reserve was mainly determined by elevation, temperature, and precipitation variables. The confirmed species were Jatropha ciliata Sessé ex Cerv., Jatropha neopauciflora Pax, Jatropha oaxacana J. Jiménez Ram. & R. Torres, Jatropha rufescens Brandegee, and Jatropha rzedowskii J. Jiménez Ram., which are distributed in four of the six defined ELU. J. neopauciflora and J. rzedowskii were the most widespread species; this last species concur in four, J. oaxacana in two, while J. rufescens and J. ciliata in one ELU, being the most restricted. The richness of the genera in the associated communities ranged from 16 to 42. The maximum and minimum importance Value indexes were observed in San Nicolas Tepoxtitlan for J. neopauciflora (53.75%) and J. rze-dowskii (1.50%). The disturbance index varied from 0.22 to 0.82, with an average of 0.51, where the livestock variable had a high contribution. Considering the risk categories of MER, we concluded that J. oaxacana requires special protection, and J. ciliata and J. rufescens were species under extinction risk. The conservation status of the plant communities inhabited by populations of Jatropha spp. was moderate, taking into account the rate of disturbance. The main factors affecting the habitats of Jatropha were livestock and human activities; the floristic composition of the surrounding plant communities has low richness. These results support the urgent need of conservation strategies to avoid the loss of important wild growing species of Jatropha populations. Rev. Biol. Trop. 63 (1): 23-33. Epub 2015 March 01.
Phytoplankton constitutes the primary producers of aquatic ecosystems and represents the food cha... more Phytoplankton constitutes the primary producers of aquatic ecosystems and represents the food chain base that supports the commercial fisheries of most water bodies. Nowadays, there is lack of information on phytoplankton assemblages of most reservoirs in Africa. To contribute with this knowledge, this study was carried out to determine the density and diversity of seasonal variations of phytoplankton species in the Bui dam area of the Black Volta, during the pre-(2011) and post-impoundment (2012) periods. For this, a three-level stratified random sampling approach was adopted for 22 months. Phytoplankton samples were obtained by towing a 0.5m diameter phytoplankton net (35μm mesh size and 0.25m 2 mouth surface area) from a non-motorized canoe through a distance of about 100m against the current from downstream to upstream of the river. In 2011, 35 species of phytoplankton belonging to four classes, Bacillariophyceae (7.6%), Chlorophyceae (43%), Cyanophyceae (48.6%) and Euglenophyceae (0.8%) were identified. In the 2012 sampling, 18 species belonging to three classes, Bacillariophyceae (2.2%), Chlorophyceae (26.1%) and Cyanophyceae (71.7%) were observed. A total of 17 species of phytoplankton, including sp. and Spirulina sp., were absent during the late post-impoundment period. Mean monthly total phytoplankton abundance decreased from June (7 384 cells/m 3) to August (106cells/m 3) in 2011. In 2012 however, mean total phytoplankton decreased from February (1 237cells/m 3) to August (4cells/m 3). The results also showed that variations occurred between seasons among some phytoplankton groups. The dry and pre-wet seasons had significantly (p<0.05) higher mean phytoplankton abundance than the wet season during the 22 months of sampling period. The biotic indices of Shannon-Wiener (H 1) were homogenously distributed in the four hydrological seasons of the two years. The phytoplankton groups, Bacillariophyceae, Chlorophyceae, Euglenophyceae and total phytoplankton differed significantly (p<0.05) between the pre-and post-impoundment periods. The total phytoplankton was also significantly (p<0.05) higher in the upstream station than the downstream station indicating the impact of the impoundment on the downstream ecology. Hence, river management strategies should be implemented by hydro-biologist to lessen the impact of the dam on the downstream ecology. Rev. Biol. Trop. 63 (1): 13-22. Epub 2015 March 01.
Toxoplasma gondii is an obligatory intracellular parasite that infects a wide range of warm-blood... more Toxoplasma gondii is an obligatory intracellular parasite that infects a wide range of warm-blooded animals and humans. Considering the severity of toxoplasmosis, side effects of current treatments, and the contribution of the ethnopharmacological knowledge for the treatment of parasitic infections, the aim of the present study was to investigate the efficacy of methanolic extracts from the fruits and leaves of Sambucus nigra against tachyzoite of T. gondii. For this, fruits and leaves of S. nigra were collected from Mazandaran province, Iran, were dried under the shade, and powdered using a commercial electrical blender. For extractions, methanol was used as solvent. virulent RH strain of T. gondii was maintained in mice and macrophages containing tachyzoites were aspirated from the peritoneal cavity. Four concentrations (5, 10, 25 and 50mg/mL) of S. nigra extract were incubated with infected macrophages for 30, 60, 120 and 180 minutes and the viability of the tachyzoites were evaluated by trypan blue staining. Results showed that S. nigra fruit extracts at the concentrations of 5 and 10mg/ mL killed 100% of T. gondii tachyzoites after 60 and 120 minutes, respectively; and concentrations of 25 and 50mg/mL killed 100% of the tachyzoites after 30 minutes. Additionally, extract of S. nigra leaves, at the concentrations of 5, 10 and 25mg/mL after 180 minutes, and concentration of 50mg/mL after 60 minutes, resulted with the highest efficacy. Our results showed that S. nigra has acceptable efficacy in vitro and the parasiticidal effect of fruit extract was significantly better than leaf extract. However, in vivo efficacy of this extract needs further investigation. Rev. Biol. Trop. 63 (1): 7-12. Epub 2015 March 01.
Public Policies: from a general vision to Isla del Coco National Park, Costa Rica. Costa Rica has... more Public Policies: from a general vision to Isla del Coco National Park, Costa Rica. Costa Rica has a set of policies emerged from a process of improvement and analysis of previous instruments and the need to consolidate the management of the Wildlife Protected Areas of the country. In this article, we review the overall framework of public policies, what it means and what it should cover; and finish with a review the overall policy framework of protected areas in Costa Rica with a focus on its application in Isla del Coco National Park. Policies must be improved, including budget, indicators and verification. Rev. Biol. Trop. 64 (Suppl. 1): S277-S290. Epub 2016 Febrary 01.
Isla del Coco is the only oceanic island in the Eastern Pacific with humid tropical climate. Its ... more Isla del Coco is the only oceanic island in the Eastern Pacific with humid tropical climate. Its forests have a particular structure with a unique array of plant species and high endemism. There are few studies on the flora or forest monitoring on the island. The population structure of Sacoglottis holdridgei was analyzed using data from six years with data points taken in 2006 and 2012, including sampling of regeneration in 2012. Sacoglottis holdridgei was the most important tree species, presenting in 2012 the highest Importance Value Index (190.7±21.8), abundance (158.5±40.3 Nha-1 or 39.5 % of the forest) and basal area (15.6 m 2 ha-1 or 72.9 % of the forest). It was present in all three height strata with dominance in the highest. Annual mortality was reported at 3.3 % and recruitment at 1.2 %. The diameter distribution of forest fits the inverted J model, but not for the reported species of which only S. holdridgei tends to adjust for DBH>40 cm. Regeneration fitted the inverted J model with values below those reported for continental forests. Even though it was the dominant species, S. holdridgei showed low regeneration values. This particular condition, give way hypotheses related to the introduction of species, species biology and climate change which could influence the future development of S. holdridgei and forests of Isla del Coco. Rev. Biol. Trop. 64 (Suppl. 1): S263-S275. Epub 2016 Febrary 01.
Illegal fishing at Isla del Coco National Park, Costa Rica. Isla del Coco National Park (ICNP), C... more Illegal fishing at Isla del Coco National Park, Costa Rica. Isla del Coco National Park (ICNP), Costa Rica, is renowned for its large aggregations of pelagic species, especially sharks (Carcharhinidae and Sphyrnidae), billfish (Istiophoridae) and tuna (Scombridae). The high abundance of these sought after species, attracts commercial fishing vessels that enter the protected waters of the Park. Illegal fisheries thus represent one of the biggest threats to the ecological integrity of this World Heritage Site. The ICNP dedicates important resources to protection and control via regular surveillance patrols, along the 12 nautical miles that have Marine Protected Area (MPA) status. During 2012, 2013 and between January and August 2014, 405 surveillance patrols within the MPA found 108 fishing lines, more than 13 000 hooks, seized more than 500 km of fishing line and 257 pelagic individuals. The yellowfin tuna (Thunnus albacares) was the most abundant species, representing more than 72.3 % of the total catch; seized individuals had a mean total length of 153.35±23.19 cm (Min=90 cm; Max=190 cm); which indicates that most individuals were adults. Analysis of monthly CPUE showed that the highest relative abundance of illegally caught T. albacores was between May and August of each year, with a mean relative abundance of 26.13±54.71, 11.63±23.79, 13.71±24.52 tunas per 1 000 hooks in 2012, 2013, 2014, respectively. This species had a high survival rate (nearly 80 % of the individuals found on the lines were still alive), probably due to the short fishing lines used by illegal fishermen, combined with the swift intervention of rangers. The CPUE of T. albacares found in this study is greater than records in Costa Rica's Exclusive Economic Zone (0.74 and 0.44 per 1 000 hooks respectively). These results highlight the importance of ICNP as an aggregation site for T. albacares and the need for its effective protection. It is important that ranger intervention continue to be as rapid and effective as possible, in order to decrease the impact of illegal fishing on the marine biodiversity of the ICNP. Rev. Biol. Trop. 64 (Suppl. 1): S249-S261. Epub 2016 February 01.
Although the Eastern Tropical Pacific is well known for its diverse fauna, the seabirds occurring... more Although the Eastern Tropical Pacific is well known for its diverse fauna, the seabirds occurring off Costa Rica's Pacific coast have received little scientific attention. With seabirds now the fastest declining avian group, a better understanding of seabird diversity and abundance in this region is urgently needed. We report on observations of Costa Rica's Pacific seabirds made during 19 days of observations on 11 offshore trips from 2006-2010. We provide, for the first time, spatially and seasonally explicit information on the distribution of 41 species of seabirds (nine families). Species diversity is higher during the dry-wet season (36 species) and wet-dry season transitions (36 species) than during the dry season (19 species). The fauna included three threatened species (Pterodroma phaeopygia, Procellaria parkinsoni, and Puffinus creatopus) and two near-threatened species (Psueudobulweria rostrata and Thalasseus elegans), highlighting the importance of Costa Rican waters for the conservation of seabirds. Rev. Biol. Trop. 64 (Suppl. 1): S235-S248. Epub 2016 February 01.
Stomatopods are a small group of marine and estuarine crustaceans that inhabit several marine eco... more Stomatopods are a small group of marine and estuarine crustaceans that inhabit several marine ecosystems including deep, shallow waters, and intertidal zones. Six species from five families have been reported from the Park. We add Coronida glasselli Manning, 1976 from rocky reef environments at Isla del Coco. In the Eastern Tropical Pacific the species was reported only from Isla Gorgona, Colombia. There are species from Isla Uva, Panamá in the National Museum of Natural History, Washington DC. Rev. Biol. Trop. 64 (Suppl. 1): S231-S233. Epub 2016 Febrary 01.
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