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| Natura: | Artículo científico |
| Lingua: | en |
| Pubblicazione: |
Universidad de Costa Rica
2007
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| Accesso online: | https://www.redalyc.org/articulo.oa?id=44955217 |
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Sommario:
- Growth rate fitting using the von Bertalanffy model: analysis of natural populations of Drepanotrema spp. snails (Gastropoda: Planorbidae) M. Andrea Roche Alejandra Rumi Diego E. Gutiérrez Gregoric Biología rates growth Argentina Planorbidae Drepanotrema spp The genus Drepanotrema includes six species in Argentina. The life cycle in natural systems ofDrepanotrema depressissimum, and D. lucidum has been little studied, except for some casual observations. Theaim of this study is to analyze main population trends (age structures, recruitment periods, life span and curvesof individual growth) in Paiva pond, Argentina. We explored growth model fitting and comparison methodologiesbetween species and environments in Paiva pond and Isla Martín García (IMG), to determine interspecificpatterns. Theoretical curves of von Bertalanffys model for each population were contrasted with samplingsusing the χ2 test. Expected sizes were transformed into a percentage of maximum size and cohorts started fromzero time, which allowed them to be independent of the real or estimated starting date and a comparison waspossible. A similar time scale was used, because the k values proved to be sensitive to time scale. Maximum sizereached by D. lucidum was 6.9 mm and by D. depressissimum 9.38 mm. Growth rates (k) fluctuated from 1.302to 1.368 in the first and 1.339 to 1.509 in the second species. No statistically significant differences were foundin growth curves among species inhabiting the Paiva pond and in the different IMG water bodies independentof the beginning of each cohort and maximum size. In general, no winter cohorts were observed, except in onepopulation of D. kermatoides (IMG). Comparing circannual and biannual growth rhythms most of the speciesreached 60 % of their development during their first year, and 85 % or more during their second year. Rev. Biol.Trop. 55 (2): 559-567. Epub 2007 June, 29. 2007 artículo científico 0034-7744 https://www.redalyc.org/articulo.oa?id=44955217 en http://www.redalyc.org/revista.oa?id=449 Revista de Biología Tropical application/pdf Universidad de Costa Rica Revista de Biología Tropical (Costa Rica) Num.2 Vol.55