Micoureus Demerarae Research Articles

The importance of sound biological information and theory for ecological economics studies valuing Brazilian biodiversity: A response to Mendonça et al. (2003)

Biodiversity valuation is a controversial issue. Mendonça et al. (2003) [Mendonça, M.J.C., Sachsida, A., Loureiro, P.R.A., 2003. A study on the valuing of biodiversity: the case of three endangered species in Brazil. Ecological Economics 46, 9–18] use data from published results of population viability analyses (PVAs) coupled with taxonomic information based on a methodology proposed by Montgomery et al. (1999) [Montgomery, C.A., Pollak, R.A., Freemark, K., White, D., 1999. Pricing biodiversity. Journal of Environmental Economics and Management 38, 1–19] to estimate the management price of three mammal species from Brazil: the golden lion tamarin ( Leontopithecus rosalia), the black lion tamarin ( Leontopithecus chrysopygus) and the long-furred woolly mouse opossum ( Micoureus travassosi). However, there are several inconsistencies in the information given by Mendonça et al. (2003) and articles from which they based their analyses. Mendonça et al. (2003) misunderstand metapopulation and extinction concepts, wrongfully interpret PVAs results, and show a lack of knowledge on mammalian taxonomy and systematics. These data are cornerstones for their analyses. Therefore, the results presented by Mendonça et al. (2003) should be viewed with caution. Despite being a controversial issue, ecological economics studies will only give reliable results and management insights if they rely on sound biological information. The lack of biological knowledge and the lack of interaction with biologists may invalidate results, and worst of all, if not detected, they may lead to dissemination of wrong information, mislead management strategies and lead to catastrophic consequences for biodiversity. Biodiversity conservation is part of an economic world, and I praise Mendonça et al. (2003) for trying to merge technical biological information to economic studies of biodiversity valuation, but sound scientific information from biological sciences is of paramount importance for the development of such multidisciplinary approaches, and the sources of such information should be biologists, not economists. For such analyses to have any chance to succeed, a collaboration of both economists and biologists is necessary.

Influence of edge and fire-induced changes on spatial distribution of small mammals in Brazilian Atlantic forest fragments

The spatial distribution of small mammals in relation to distance from forest edges, before and after fire, was studied in Atlantic Forest fragments in Brazil. None of nine species was captured exclusively on either edges or forest interior. Before the fire only the rodents Akodon cursor and Oecomys con-color were captured more often at the edge than randomly expected. After the fire only A. cursor remained associated with edges; it had increased in number and penetrated farther than before into the forest fragments. The marsupial Micoureus demerarae became more restricted to the forest interior than randomly expected. These results suggest that small mammal species tolerant to habitat changes induced by edge effects and fire have better chances to survive in forest fragments.

A radio tracking study of home range and movements of the marsupial Micoureus demerarae (Thomas) (Mammalia, Didelphidae) in the Atlantic forest of south-eastern Brazil

From August 2001 to July 2002 the home range and movements of seven Micoureus demerarae (Thomas, 1905) (three males and four females) were investigated using radio tracking in the União Biological Reserve, state of Rio de Janeiro, south-eastern Brazil. A total of 436 locations was obtained and home range estimated with fixed Kernel (95% of data points), and minimum convex polygon (MCP) methods, with 100 and 95% of data points. Male home ranges estimated by MCP (100%) ranged from 5.4-24.2 ha and females from 0.3-10.7 ha. Corresponding figures calculated with Kernel (95%) were 4-10.9 ha for males and 1.3-5.9 ha for females. Animals travelled on average 423 m/night, with males travelling significantly further (582.8 m/night) than females (335.1 m/night) (t test, t = 3.609, p = 0.001). We concluded that radio tracking produced much larger home ranges than those estimated with traditional live-trapping techniques, suggesting that the latter might underestimate ranging when the area covered with traps is relatively small (ca. 1 ha or less). Radio tracking also indicated that M. demerarae, although predominantly arboreal and weighting only ca. 130 g., has movements similar in magnitude to larger-sized terrestrial didelphimorph marsupials, such as Didelphis Linnaeus, 1758, Philander Linnaeus, 1758 and Metachirus (Desmarest, 1817).

Genetic variation and geographical structure of five mouse‐sized opossums (Marsupialia, Didelphidae) throughout the Guiana Region

AbstractAim and location To study the patterns of genetic variation and geographical structure of five forest‐dwelling didelphid species distributed throughout the Guiana Region (Marmosops parvidens, M. pinheiroi, Monodelphis brevicaudata, Marmosa murina, Micoureus demerarae) and place the results for wide‐ranging species (M. murina, M. demerarae) in the broader geographical context of the rest of the taxon ranges based on published data.Methods Variation in the mitochondrial cytochrome b gene were analysed in order to assess intra‐specific sequence divergence as well as haplotypic and nucleotide diversity among populations. Relationships between haplotypes were inferred by cladistic (maximum parsimony) and probabilistic (maximum likelihood) approaches, allowing comparisons between tree topologies and patterns of populations geographical distribution.Results Phylogenetic analysis of the Guiana Region populations suggest the lack of common patterns of geographical structure among mouse‐sized opossums except for both Marmosops species. Marmosops parvidens and M. pinheiroi showed individuals from Surinam strongly related with those from Guyana, and haplotypes from French Guiana having a basal position. Concerning Micoureus demerarae, haplotypes from Venezuela were positioned as ancestral, in contrast with Monodelphis brevicaudata, whose French Guiana haplotypes were clustered in a basal position. No evidence of geographical structure was observed for Marmosa murina. Genetic variation within Guiana Region populations fluctuated between 1% for M. murina and 7% in the case of M. brevicaudata. Regarding the widely distributed species, phylogeographical structure at the scale of the Amazon Basin suggests that Guiana Region populations are the sister group of south‐eastern Amazonian and Atlantic Forest populations, thus resulting in an eastern clade well separated from the western Amazonian regions.Main conclusions Monophyly of mouse‐sized opossums haplotypes over the Guiana Region confirms the presence of a well‐differentiated zoogeographical area relative to other Amazonia bioregions. Low genetic diversity among Guiana Region samples suggests a relatively recent origin of populations dating from later Miocene and Pleistocene periods. Moreover, nucleotide and haplotypic diversity values suggest an evolutionary scenario of rapid population growth and dispersal over the Guiana territory, from an ancestral population with small effective size. Dispersal events – rather than vicariance – seem to be responsible for the present genetic and phylogeographical patterns observed in the Guiana Region.

Vertical stratification of small mammals in the Atlantic rain forest of south-eastern Brazil

Patterns of vertical stratification and canopy utilization by rodents and marsupials were analysed in two contiguous Atlantic forests at different altitudes (100 m and 900 m asl). Twenty-two species were captured using live traps placed at ground level, in the understorey (1.5–2.0 m), and in the canopy (6–15 m) over 2 y; seven species (32%) were mainly or exclusively arboreal. Community composition and relative abundance of species in the different vertical strata were not similar, with a general reduction in the number of species, and in abundance in the upper layers. The following species were captured mainly or exclusively in the canopy: Micoureus demerarae and Gracilinanus microtarsus (Didelphimorphia, Didelphidae); Wilfredomys pictipes , Oecomys aff. concolor , and Rhipidomys aff. macrurus (Rodentia, Muridae); and Nelomys nigrispinus (Rodentia, Echimyidae). Our results indicated that altitudinal changes in Atlantic forest areas may alter the community composition of different forest layers but they do not seem to alter greatly specific patterns of vertical habitat utilization. Similar-sized species tended to differ in their patterns of vertical utilization of habitat with the exception of terrestrial akodontine rodents (genera Akodon , Thaptomys , Oxymycterus and Brucepattersonius ). Rodents (mainly Oryzomys russatus ) dominated captures at ground level at both sites but Akodontinii were numerous only at the highest site. Unlike other neotropical forests, marsupials did not dominate canopy captures.

Forest Structure and Vertical Stratification of Small Mammals in a Secondary Atlantic Forest, Southeastern Brazil

This study investigated the differential capture rates of small mammals in different strata of a secondary forest, Minas Gerais State, Brazil. From March through October 1994 mammals were live-trapped at ground, understory and mid-story level. Five species of marsupials and six species of rodents were recorded. Didelphis aurita, Marmosops incanus, Metachirus nudicaudatus, and Oryzomys spp. were captured mostly on the ground, while Caluromys philander, Micoureus demerarae, Rhipidomys mastacalis and Sciurus aestuans were sampled mainly at 5-12 m height. Species richness was correlated with structural complexity of the forests surveyed. On the other hand, a relationship between species richness and habitat heterogeneity was not detected. These results suggest that local saturation of small mammal species, rather than regional species richness, is determined by the level of habitat complexity. The conservation of stratified forests, such as those found at the Parque Estadual do Rio Doce and the other sites in the Rio Doce valley, are therefore essential for the maintenance of local species diversity.

Diet of the Marsupial Micoureus demerarae in Small Fragments of Atlantic Forest in Southeastern Brazil

The diet of the marsupial Micoureus demerarae was studied from fecal samples obtained from live-trapping in Atlantic Coastal Forest fragments at Poço das Antas Biological Reserve, southeastern Brazil, from 1995 to 1997. Among arthropods, the most frequent food items belonged to the orders Coleoptera and Hymenoptera, whereas Arachnida, Orthoptera, Hemiptera and Lepidoptera were also frequent. Lepidoptera and Diptera were represented mostly by larvae and pupae. Crustaceans of the orders Copepoda and Isopoda were also found. Plants were represented by seeds of species from secondary vegetation, mostly belonging to the families Piperaceae, Moraceae and Cecropiaceae, which should reflect frugivory. Predominance of arthropods in the diet was consistent with previous studies. Diet composition was remarkably constant among fragments, sexes, age classes, breeding versus non-breeding seasons, and climatic categories (dry versus humid months). The only significant difference was that diversity of arthropods was higher in the non-breeding than in the breeding season, but this was likely to be due to sampling effects. Given the natural abundances of the food items, the constancy of the diet is likely to reflect opportunism rather than food selection.

Frequency of movements of small mammals among Atlantic Coastal Forest fragments in Brazil

Rates of interfragment movements were estimated for small mammals inhabiting a group of eight Atlantic Coastal Forest fragments, surrounded by grassland matrix, in order to understand the degree to which each species' population was isolated. Didelphis aurita showed the greatest movement rate (19.4% of recaptures showing interfragment movements), followed by Metachirus nudicaudatus (10.0%), Philander frenata (7.5%), Nectomys squamipes (3.6%), Micoureus demerarae (1.2%) and Akodon cursor (0.25%). Interfragment movements were not detected for Caluromys philander, Oecomys concolor and Oligoryzomys nigripes. Species can be placed along a continuum which goes from species that are represented by a single population in the whole study area, through those with metapopulations, to species that have isolated populations in each fragment. Ability to move among fragments was not related to abundance in the matrix; nevertheless, such ability helps to explain the persistence of species in fragments otherwise too small to support viable populations.

KARYOTYPES OF NINETEEN MARSUPIAL SPECIES FROM BRAZIL

Karyotypes of 127 individuals, representing 19 species of 10 genera of Brazilian marsupials (Didelphidae) were determined, with karyotypes of Gracilinanus emiliae and G. microtarsus, Marmosops incanus, Thylamys velutinus, and Philander frenata being described for the 1st time. The specimens were collected from 24 localities, in an area between 4°N (Surumu, Roraima) and 31°S (Mostardas, Rio Grande do Sul), in Brazil. Only 3 diploid numbers were found, 2n = 14 in G. emiliae, G. microtarsus, G. agilis, Marmosa murina, Marmosops parvidens, M. incanus, Micoureus demerarae, and T. velutinus; 2n = 18 in Monodelphis dimidiata, M. brevicaudata, M. kunsi, and M. domestica; and 2n = 22 in Chironectes minimus, Lutreolina crassicaudata, Didelphis albiventris, D. aurita, D. marsupialis, Philander opossum, and P. frenata.

Patch relative importance to metapopulation viability: the neotropical marsupial Micoureus demerarae as a case study

As metapopulation dynamics is thought to play an important role in the conservation of mammals, mainly owing to the fragmentation process, a Population Viability Analysis (PVA) was used to evaluate the role and importance of individual patches to the metapopulation persistence of the long-furred wooly mouse opossum, Micoureus demerarae, a neotropical arboreal marsupial. The metapopulation under study comprises eight small Atlantic Forest patches at Poco das Antas Biological Reserve, southeastern Brazil. The analysis indicates that the local populations may be divided into three groups: (1) in the smallest and most isolated patches, where they are the most endangered, (2) in five circular-shaped and relatively well-connected patches and (3) in the largest patch with the most persistent local population. Knowledge of how specific patches influence metapopulation dynamics is an important tool in guiding management strategies, and dynamics can be affected by factors like patch size and relative position. It seems that for this particular case, probability of metapopulation extinction, mean metapopulation size, heterozygosity and mean growth rate were the most informative measures to evaluate a patch's contribution to metapopulation persistence. Despite all controversies, metapopulation theory, when carefully and properly applied, is a valuable tool in conservation biology.

Diet of two marsupials, Lutreolina crassicaudata and Micoureus demerarae, in a coastal Atlantic Forest island of Brazil

Article Diet of two marsupials, Lutreolina crassicaudata and Micoureus demerarae, in a coastal Atlantic Forest island of Brazil was published on January 1, 2002 in the journal Mammalia (volume 66, issue 3).

Population dynamics of the marsupial Micoureus demerarae in small fragments of Atlantic Coastal Forest in Brazil

Patterns of population fluctuation, reproductive activity and age structure were studied in populations of the marsupial Micoureus demerarae occupying two small (7.0 and 8.8 ha) fragments of Atlantic Coastal Forest in southeastern Brazil, from 1995 to 1998. Males, but not females, were observed to move between populations. Estimated sizes of the populations in each fragment were very small, usually below 20 individuals. Breeding usually occurred from September to April. Population peaks came mostly by the end of this season, the delay reflecting the time required for the young to become trappable. In August 1997, the area was hit by a fire severely affecting the smaller fragment. Populations were synchronous before the fire, although they became asynchronous after it, possibly in the short term only. Small population sizes, synchrony and presumable male-biased migration are all likely to make the set of populations more vulnerable to extinction than expected for a metapopulation.

Functional-adaptive anatomy of the forelimb in the Didelphidae, and the paleobiology of the Paleocene marsupials Mayulestes ferox and Pucadelphys andinus.

An attempt to determine the locomotor activities of Mayulestes ferox (Borhyaenoidea) and Pucadelphys andinus (Didelphoidea) from the early Paleocene site of Tiupampa (Bolivia) is presented. The functional anatomy of the forelimbs of these South American marsupials is compared to that of some living didelphids: Caluromys philander, Micoureus demerarae, Marmosa murina, Didelphis marsupialis, Monodelphis brevicaudata and Metachirus nudicaudatus. Deductions from bone morphology to myology and locomotor behavior in the fossils are inferred from the comparisons with living forms. Some features of the postcranial skeleton, indicative of arboreal adaptations, are found in the extinct marsupials: anteriorly projected acromion, hemispherical head of the humerus, extended humeral lateral epicondylar ridge, medially protruding humeral entepicondyle, proximal ulnar posterior convexity, and deep flexor fossa on the medial side of the ulna. But other features are related to a more terrestrial pattern: the well-developed tubercles of the humeral head, the elongated olecranon process of the ulna, and the oval shape of the radial head. Mayulestes had clear arboreal abilities, but, as a predaceous mammal, probably hunted on the ground. Pucadelphys was less specialized, close to the living Monodelphis, a terrestrial insectivorous form with some skeletal features related to arboreal locomotion that are probably plesiomorphic for marsupials.

Metapopulation viability of the marsupial Micoureus demerarae in small Atlantic forest fragments in south‐eastern Brazil

AbstractA population viability analysis (PVA) was carried out for populations of the arboreal didelphid Micoureus demerarae in eight small (1.5–15.0 ha) forest fragments in south‐eastern Brazil. Analysis was based on field data obtained through demographic studies carried out since 1995. Populations are small, but connected by dispersing individuals, thus forming a metapopulation. Frequency of catastrophic fires was estimated from the Reserve's historical records. We used the computer package VORTEX for all analyses. All populations and the metapopulation were found to be endangered within 100 years (extinction probability > 0.98). A sensitivity analysis was run varying six parameters: three demographic (sex ratio, migration and mortality rates), two environmental (K, fire frequency) and one genetic (level of inbreeding depression). Genetics, K, mortality rates and sex ratio seemed to play major roles to population persistence, whereas catastrophes and migration rates had a secondary role. Among demographic factors, extinction rate was least sensitive to migration rate. Micoureus demerarae can be used as a model species, thus improving our knowledge of how extinction‐prone populations of neotropical arboreal marsupials in forest fragments might be, and which management actions could decrease such risks.

Metapopulation viability of the marsupial Micoureus demerarae in small Atlantic forest fragments in south-eastern Brazil

Metapopulation viability of the marsupial Micoureus demerarae in small Atlantic forest fragments in south-eastern Brazil

(T2AG3)n telomeric sequence hybridization suggestive of centric fusion in karyotype marsupials evolution.

It has been suggested that the karyotype of the marsupials derived from a low diploid number (2n = 14) which originated, through fissions of biarmed chromosomes, the karyotypes with a higher 2n. The telomeric sequence (T2AG3)n was in situ hybridized to the chromosomes of Gracilinanus microtarsus and G. emiliae, Micoureus demerarae and Marmosa murina, species with 2n = 14, in Monodelphis sp., M. domestica, M. kunsi and M. brevicaudata with 2n = 18, and in Lutreolina crassicaudata, Didelphis albiventris, Chironectes minimus, Philander opossum and P. frenata, all of them with 2n = 22. The probe hybridization occurred in the telomeric regions of both arms, short and long, of all chromosomes of the complement of all individuals of all species analysed. However, in some pairs of the karyotypes of Gracilinanus microtarsus and Micoureus demerarae (with 2n = 14), and in Monodelphis sp., M. domestica, M. kunsi and M. brevicaudata (2n = 18) ectopic signs of hybridization were detected proximal to the centromeres, suggesting the retention of this telomeric sequence in the centromeric regions of some chromosomes of these species. Based on these results, it is proposed that the karyotype of marsupials evolved from a 2n = 22 to a 2n = 14, by means of chromosomal fusions.

Functional-adaptive anatomy of the forelimb in the didelphidae, and the paleobiology of the paleocene marsupialsMayulestes ferox andPucadelphys andinus

An attempt to determine the locomotor activities of Mayulestes ferox (Borhyaenoidea) and Pucadelphys andinus (Didelphoidea) from the early Paleocene site of Tiupampa (Bolivia) is presented. The functional anatomy of the forelimbs of these South American marsupials is compared to that of some living didelphids: Caluromys philander, Micoureus demerarae, Marmosa murina, Didelphis marsupialis, Monodelphis brevicaudata and Metachirus nudicaudatus. Deductions from bone morphology to myology and locomotor behavior in the fossils are inferred from the comparisons with living forms. Some features of the postcranial skeleton, indicative of arboreal adaptations, are found in the extinct marsupials: anteriorly projected acromion, hemispherical head of the humerus, extended humeral lateral epicondylar ridge, medially protruding humeral entepicondyle, proximal ulnar posterior convexity, and deep flexor fossa on the medial side of the ulna. But other features are related to a more terrestrial pattern: the well-developed tubercles of the humeral head, the elongated olecranon process of the ulna, and the oval shape of the radial head. Mayulestes had clear arboreal abilities, but, as a predaceous mammal, probably hunted on the ground. Pucadelphys was less specialized, close to the living Monodelphis, a terrestrial insectivorous form with some skeletal features related to arboreal locomotion that are probably plesiomorphic for marsupials.

Intraspecific variation in the distribution of the interstitial telomeric (TTAGGG)n sequences in Micoureus demerarae (Marsupialia: Didelphidae).

The distribution of the telomeric sequence (TTAGGG)n was studied in chromosomes of Micoureus demerarae (2n = 14), a South American marsupial, by fluorescence in-situ hybridization (FISH). The telomeric repeat sequence was present at both ends of all chromosomes, but also various interstitial telomeric sequences (ITS) were detected in the pericentromeric heterochromatic regions. Intraspecific differences in the number of ITS (2 to 8) were observed without intraindividual variation. The presence of telomere-like sequences in the same regions of constitutive heterochromatin suggest that these segments are not necessarily remnants of true telomeres resulting from chromosome rearrangements but could be part of the satellite DNA.

Use of space by the marsupial Micoureus demerarae in small Atlantic Forest fragments in south-eastern Brazil

The spatial patterns presented by the marsupial Micoureus demerarae were studied through capture–mark–recapture in two small Atlantic Forest fragments (areas 7.1 and 8.8 ha). The study took place from March 1995 to August 1997. Considering all captures of each individual, males did not have larger home ranges within the fragments than did females. A negative correlation was found between home range sizes and population densities. For males, home ranges overlapped often, and were larger during the breeding season. For females, home ranges did not overlap except for a short period when there were many individuals present, and home range sizes were not significantly larger in the breeding season. Five movements between the two forest fragments were detected, across 300 m of open vegetation. All the movements were performed by males during the reproductive season. M. demerarae in the small fragments therefore displays a metapopulation structure, although possibly an atypical one where only males disperse.

Interactions between aroids and arboreal mammals in the Brazilian Atlantic rainforest

The Brazilian Atlantic rainforest harbours at least 129 non-volant mammal species. There is also a diverse and numerous epiphytic flora associated with this Neotropical rainforest, including several species of Araceae. Nevertheless, knowledge of the ecology of this group of plants and its interaction with animals is poor. In this study we investigated the interactions between epiphytic aroids and arboreal mammals in the Atlantic forest. We carried out the field work between November 1995 and June 1997 in the Parque Estadual Intervales, southeastern Brazil, a still well preserved forest area of approximately 490 km2. We analysed faecal samples from primates (Cebus apella and Brachyteles arachnoides), collected during observations in the field, and marsupials (Didelphis aurita, Micoureus demerarae, Gracilinanus microtarsus), collected from animals captured monthly or bi-monthly in live-traps. We recorded 17 species of Araceae in the study area. The seeds of eight species occurred in the faecal samples: Anthurium harrissi, Monstera adansonii, Philodendron corcovadense, P. appendiculatum, P. exymium, P. crassinervium, P. obliquifolium, and Heteropsis oblongifolia. Aroids were present in faecal samples of the primates during most of the year, with a mean monthly percentage of occurrence of about 56.2%. For marsupials, aroids also were a seasonally important food source, as between November and June the mean monthly percentage of occurrence in faecal samples was about 26.5%. Our data indicate that aroids are an important food source for arboreal and semi-arboreal mammals and that these animals may play an important role as seed dispersers of this group. Aroids and arboreal mammals appear to interact more strongly in Atlantic forest than in other Neotropical forests.