História natural, biologia reprodutiva, parâmetros populacionais e comunidades de pequenos mamíferos não-voadores em três habitats florestados do Pantanal de Poconé, MT

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The non-volant small mammals were studied at Fazenda Aparecida in the municipality of Nossa Senhora do Livramento, Pantanal of Poconé, MT, Brazil. The objectives of this study were to describe some aspects of natural history, reproductive biology, populations parameters of some species, as well as describe and compare communities of small mammals in three forest habitats representative of the region. In all, three collecting methods were used to survey the species: linear transects, monitoring program and random collections. The first two methods used Sherman and hookcage traps. Linear transects were set in diverse open and closed physiognomies, between June and August 2005, and all captured animals were collected in order to form a reference collection. The monitoring program was carried out monthly between February 2006 and August 2007 (except January and April 2007) in ten sample grids, with one hundred trapping points in each grid, in three types of local forest denominated as cambarazal (3), landi (3) and cordilheira (3) and in an area of campo de murundus (1). Cambarazal, landi and campo de murundus are subject to seasonal inundation whereas the cordilheiras remain dry year round. Individuals captured during the monitoring program received a numbered ear tag and were released. Total capture effort was 41,837 traps.night and 15 species were registered: six Didelphidae (Caluromys philander, Didelphis albiventris, Gracilinanus agilis, Micoureus demerarae, Monodelphis domestica, Philander opossum), eight Cricetidae (Calomys cf. callosus, Holochilus sciureus, Hylaeamys megacephalus, Necromys lasiurus, Oligoryzomys cf. fornesi, Oligoryzomys nigripes, Oecomys mamorae, Oecomys roberti) and one Echimyidae (Thrichomys pachyurus). Only two species were captured at all three forest habitats (M. demerarae e G. agilis), three were only captured at flooded habitats (P. opossum, H. megacephalus e O. roberti) and six species were captured in only one habitat: C. philander and D. albiventris in landis, H. sciureus in cambarazal, and N. lasiurus, O. nigripes, and T. pachyurus in cordilheiras. The species registered in this study represent 47% of non-volant small mammals species described for the Pantanal floodplain. Most of analyzed marsupials presented reproductive period between the end of dry season and during flooded season, while most of rodents species presented reproductive activity throughout the year, with an intensification of reproductive efforts in the same period described for marsupials. The robust design from MARK software was used to analyze G. agilis, M. demerarae, M. domestica and O. roberti populations. The objective was to test the hypothesis of seasonal interference on survival, immigration and emigration parameters as a function of the habitat: at flooded habitats these parameters would be different at presence and absence of water in the ground; in cordilheiras the variation would be distinct for three seasons: flooded, water leaving, and dry. The hypothesis was corroborated by the populations in cordilheiras, but for most species at flooded habitats the hypothesis was not confirmed. Density variation observed throughout the monitoring program pointed out to a population decline between the end of water leaving and the beginning of dry seasons, being better explained by life history, recruitment and reproductive biology of the species than by seasonal interference on population dynamics. The species richness estimation (1st order Jackknife) did not reach an asymptote for any forest habitats. A two-way ANOVA performed between habitats, between seasons, and for habitat-season association did not detect differences in species richness average, even habitatseason association. Although species richness was similar for the three habitats, there were differences in the composition of species. The test t applied to the Shannon-Weaver (H) diversity index indicated that there were no differences in the observed diversity between cambarazal and cordilheira, but these were significantly higher than the diversity observed in landi. Qualitative and quantitative Sorensens coefficients pointed to a higher similarity between seasons of the same habitat than between habitats in the same season. The coefficients also showed more similarity between seasonal flooded habitats. The results of this study make evident the importance of those three forest habitats for maintaining the diversity of non-volant small mammal of the Pantanal of Poconé.

ASSUNTO(S)

marsupiais ciencias biologicas história natural pequenos mamíferos comunidades mato grosso roedores biologia reprodutiva parâmetros populacionais pantanal

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