Carlos Eduardo Viveiros Grelle

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.

A global meta-analysis on the ecological drivers of forest restoration success

Two billion ha have been identified globally for forest restoration. Our meta-analysis encompassing 221 study landscapes worldwide reveals forest restoration enhances biodiversity by 15–84% and vegetation structure by 36–77%, compared with degraded ecosystems. For the first time, we identify the main ecological drivers of forest restoration success (defined as a return to a reference condition, that is, old-growth forest) at both the local and landscape scale. These are as follows: the time elapsed since restoration began, disturbance type and landscape context. The time elapsed since restoration began strongly drives restoration success in secondary forests, but not in selectively logged forests (which are more ecologically similar to reference systems). Landscape restoration will be most successful when previous disturbance is less intensive and habitat is less fragmented in the landscape. Restoration does not result in full recovery of biodiversity and vegetation structure, but can complement old-growth forests if there is sufficient time for ecological succession.

Ecology of small mammals in a Brazilian rural area

A small mammal study was carried out in Pamparrao valley, Sumidouro, State of Rio de Janeiro, Brazil, from June 1991 to July 1996. The area was characterised by small rural properties with vegetable plantations, pasture lands and small forest fragments. Small mammals were captured in seven line transects along the valley. Eleven small mammal species were captured: the didelphid marsupials Didelphis aurita, Philander frenata and Monodelphis americana, and the rodents Nectomys squamipes, Akodon cursor, Oligoryzomys nigripes, Bolomys lasiurus, Oecomys concolor (Sigmodontinae), Rattus ratlus (Murinae), Proechimys iheringi and Euryzygo-matomys guiara (Echimyidae). The heterogeneous habitat configuration probably allowed the occurrence of marsupials and more rodent species when compared to studies in monoculture areas.

Preliminary observations on habitat, support use and diet in two non-native primates in an urban Atlantic forest fragment: The capuchin monkey (Cebus sp.) and the common marmoset (Callithrix jacchus) in the Tijuca forest, Rio de Janeiro

Space is an important dimension of the ecological niche. Differentiation in the use of vertical strata of the forest is related to species body size, and explains in part species coexistence at a local scale. Large neotropical primates dwell in the canopy, moving quadrupedally on large branches, whereas smaller species leap between narrow branches in the understory. We tested this general pattern by observing focal individuals of the capuchin monkey (Cebus sp.) and the common marmoset (Callithrix jacchus), both non-native species, living in a forest fragment within the Rio de Janeiro city. Results were in accordance with the pattern for neotropical primates. Vertical use of the forest seems to be related with ecological interactions, especially for C. jacchus restricted to the lower strata due to aerial predation. Preliminary observations on diet corroborate the omnivory of Cebus and the gum feeding characteristic of C. jacchus. For Cebus sp. the exotic jack-fruit (Artocarpus heterophyllus) was the most important food item. Predation of both primates on vertebrates, especially by C. jacchus on passerines, could cause an uncommon impact on prey populations. In spite of anthropogenic impact, these non-native primates maintain the general pattern of habitat, support use and diet of the same or similar species in native neotropical communities.

Is there a correlation between abundance and environmental suitability derived from ecological niche modelling? A meta‐analysis

It is thought that species abundance is correlated with environmental suitability and that environmental variables, scale, and type of model fitting can confound this relationship. We performed a meta-analysis to 1) test whether species abundance is positively correlated with environmental suitability derived from correlative ecological niche models (ENM), 2) test whether studies encompassing large areas within a species range (> 50%) exhibited higher AS correlations than studies encompassing small areas within a species range (< 50%), 3) assess which modelling method provided higher AS correlation, and 4) compare strength of the AS relationship between studies using only climatic variables and those that used both climatic and other environmental variables to derive suitability. We used correlation coefficients to measure the relationship between abundance and environmental suitability derived from ENM. Each correlation coefficient was considered an effect size in a random-effects multivariate meta-analysis. In all cases we found a significantly positive relationship between abundance and suitability. This relationship was consistent regardless of scale of study, ENM method, or set of variables used to derive suitability. There was no difference in strength of correlation between studies focusing on large or small areas within a species’ range or among ENM methods. Studies using other variables in combination with climate exhibited higher AS correlations than studies using only climatic variables. We conclude that occurrence data can be a reasonable proxy for abundance, especially for vertebrates, and the use of local variables increases the strength of the AS relationship. Use of ENMs can significantly decrease survey costs and allow the study of large-scale abundance patterns using less information. Including only climatic variables in ENM may confound the relationship between abundance and suitability when compared to studies including variables taken locally. However, modelers and conservationists must be aware that high environmental suitability does not always indicate high abundance.

Limites Climáticos e Vegetacionais das Distribuições de Cebus nigritus e Cebus robustus (Cebinae, Platyrrhini)

Os primatas do gênero Cebus apresentam ampla distribuição geográfica, estendendo-se por toda a região Neotropical. Os macacos-prego (subgênero Sapajus) são exclusivos da América do Sul, enquanto que os caiararas (subgênero Cebus) ocorrem na Amazônia e América Central. Estes animais são notáveis por explorarem habitats diversos. A proposta taxonômica utilizada no presente estudo foi desenvolvida por Silva Jr. (2001), considerando Cebus nigritus e C. robustus como espécies válidas, pertencentes ao subgênero Sapajus, que compreende ainda C. apella, C. macrocephalus, C. libidinosus, C. cay e C. xanthosternos.

Distribution, population size and conservation of the endemic muriquis ( Brachyteles spp.) of the Brazilian Atlantic Forest

Muriquis are endemic primates of the Brazilian Atlantic Forest, with two recognized species: Brachyteles hypoxanthus and Brachyteles arachnoides . Although the state of Rio de Janeiro is the type locality for B. arachnoides the muriqui population of this region was, until recently, poorly known. We report our surveys for muriquis in seven localities in the state. Our objectives were to estimate the number of muriquis remaining and to identify local threats. We recorded muriquis in Parque Nacional da Serra dos Orgaos, Parque Nacional do Itatiaia and Guapiacu Private Reserve. Based on our sightings and information from local people we estimate that the remaining muriquis in Rio de Janeiro total c. 160, with 110 B. arachnoides and 50 B. hypoxanthus . The most severe threat to muriquis in these areas is hunting, followed by small population sizes, habitat fragmentation, forest disturbance and ecotourism. Central Rio de Janeiro state still harbours large tracts of intact forests potentially available to muriquis. Thus, if conservation actions could be targeted to mitigate the main threat of hunting there is potential for the recovery of muriquis in the state of Rio de Janeiro, at least in the short-term.

Is the Atlantic Forest protected area network efficient in maintaining viable populations of Brachyteles hypoxanthus

Habitat loss and fragmentation are serious threats to biodiversity conservation in the Atlantic Forest. A network of protected areas is essential to the protection of native biodiversity. However, internal and external factors may threaten the preservation of biota, thus population viability analyses (PVA) are important tools in protected area design and management planning. A PVA was carried out, using the computer package VORTEX, to assess the effectiveness of the protected area network within the Atlantic Forest in Brazil in retaining viable populations of the endemic primate Brachyteles hypoxanthus. The Brazilian Atlantic Forest has 42 protected areas within B. hypoxanthus geographic distribution area, and only five of those were considered to retain viable populations for 50 generations, whereas 28 were predicted to suffer from genetic decay, seven from both genetic decay and demographic stochasticity, and two of them are probably extinct populations. The model indicates that although the protected area network of the Atlantic Forest will likely keep B. hypoxanthus populations for the next 50 generations, most of them (35 out of 42, or 83%) will be facing some kind of demographic and/or genetic problem and will probably need management actions to be implemented in order to ensure their persistence.

Increasing strict protection through protected areas on Brazilian private lands

A key strategy to reduce habitat loss and fragmentation involves the establishment of protected areas (PAs). Worldwide, c. 13% of land lies within PAs, but only 6% is subject to the more restrictive International Union for the Conservation of Nature (IUCN) categories I-IV. Private PAs may contribute to this figure, but require general guidance principles for their management. The Brazilian ‘Private Natural Heritage Reserves’ (RPPNs) constitute an example of good PA management, employing seven principles that should guide the creation of all private PAs. RPPNs have legal status and long-term security, allow only for indirect human uses, and provide a strategic conservation role in highly fragmented landscapes by improving connectivity. However, RPPNs are virtually absent from the World Database on Protected Areas, and given Brazils continental size, and the considerable and increasing number of RPPNs in Brazil, this omission has the potential to skew accurate quantification of the area of land subject to strict protection. The RPPN model can make an important contribution to the discussion of the role of private PAs in conservation, especially in the tropics.

Habitat quality versus spatial variables as determinants of small mammal assemblages in Atlantic Forest fragments

Fragment size, isolation, and matrix properties have received considerable attention as predictors of species richness, abundance, and composition in habitat patches. However, measurements of habitat attributes or habitat quality are more directly related to the proximate effects of habitat fragmentation and may be more determinant of assemblages than traditional explanatory variables at local scales. We determine how habitat structure in fragments—a measure of habitat quality—compares to fragment size, isolation, and matrix properties as determinants of richness, abundance, and composition of non-volant small mammals in a fragmented landscape of Atlantic Forest. Small mammals were surveyed once in 25 fragments in the Macacu River watershed, Rio de Janeiro, Brazil, from 1999 to 2001 and 2005 to 2009. A total of 83 candidate models were formulated and compared by Akaike Information Criteria. Habitat structure was one of the main determinants of small mammal assemblages in fragments, as important as fragment isolation for species composition and climatic season for species richness. Rodents were more abundant in fragments with increased overstory and understory vegetation density and more fallen logs. The contrary pattern was found for overall species richness and for species of terrestrial habit, which were more abundant in fragments with more open forest: decreased overstory and understory vegetation density and less fallen logs. Habitat quality in fragments may be a more important determinant of assemblages of small mammals and other vertebrates than previously considered in landscape and land use studies.