Non-volant Small Mammals Research Articles

Gut Analysis of Small Non-Volant Mammals of Mt. Makiling, Luzon Island, Philippines

Three non-native species (Rattus exulans, R. tanezumi and Mus musculus) of small non-volant mammals were recorded along various elevational gradients of Mount Makiling. Invertebrate remains and plant matter comprised the bulk of their diets based on the food items identified. The identified plant matter were leaves and seeds while invertebrates were easily identifiable through body parts such as legs, head and antennae. Other contents identified including vertebrate remains such as hair/fur, feathers and bones, plastics, rubber, stones, and intestinal worms were noted. Based on the calculated relative abundance of each food type, there is no significant difference in the diets of the three non-native rodent species. Preliminary results suggest that introduced rodents in Mt. Makiling have broad diets and there are no indications that their main diet includes native wildlife species. Traces of vertebrate remains, however, may indicate potential predation on wildlife species and further studies are needed to clarify this.

Patterns of arboreal and terrestrial space use by non-volant small mammals in an Araucaria forest of southern Brazil

Despite the advances in the techniques for researching arboreal small mammals, detailed ecological data, such as habitat use patterns, are practically nonexistent for many species. Using 150 live-traps installed on the ground, understory (1.0-5.0m) and canopy (>5.0m) we investigated patterns of arboreal and terrestrial space use by small mammals in an Araucaria Forest in southern Brazil (29°29'08″S; 50°12'26″W). We also measured 19 microhabitat variables that could potentially influence the abundance of such mammals on each trap station. The results indicated that Akodon montensis and A. serrensis were mainly terrestrial. Delomys dorsalis was also terrestrial, but it also used understory (17.24% of captures). Juliomys sp. and Gracilinanus microtarsus were the most arboreal small mammals recorded. A. montensis was associated with dense vegetation, while A. serrensis selected positively opened areas. Juliomys sp. and G. microtarsus were associated to microhabitat variables related to the access and movement within the canopy. Moreover, bromeliads on arboreal layer were an important factor for these two arboreal species. This is the first study to report microhabitat associations by Juliomys sp. and A. serrensis, and we demonstrated that vertical stratification and microhabitat use were both synergic mechanisms to determine habitat use by small mammals on the Araucaria Forest of southern Brazil.

A Regional Study of Diversity and Abundance of Small Mammals in Ohio

The goal of this study was to obtain information on diversity, abundance, and distribution of non-volant small mammals in 4 major habitat types in each of 5 regions of Ohio. We trapped in 31 study areas, representing 39 counties, for 3 consecutive nights for a total of 38,400 trap nights. We established eight 100-m transects (each with 10 live traps, 20 snap traps, and 20 pitfall traps) per study area in woodland, oldfield, grassland-pasture, or restored prairie-wetland habitats. We captured fourteen species of small mammals (shrews and rodents <100 g in body mass), but 97% of the 2150 captured consisted of just 4 species: Microtus pennsylvanicus (Meadow Vole; 31%), Peromyscus leucopus (White-footed Mouse; 29%), Blarina brevicauda (Short-tailed Shrew; 21%), and Sorex cinereus (Masked Shrew; 16%). Regional differences in abundance of small mammals (captures/100 trap nights) and species diversity (H') were not significant (P > 0.05). Seven species of interest were captured in low numbers (<10) and 2 others, Reithrodontomys humulis (Eastern Harvest Mouse) and Myodes gapperi (Red-backed Vole), were not captured in the course of the 2-year study.

Subsidies for a poorly known endemic semiarid biome of Brazil: non-volant mammals of an eastern region of Caatinga

The mammalian fauna of the eastern Caatinga, a Brazilian semiarid biome, was surveyed in the dry and wet seasons aiming to contribute to the knowledge of this poorly known region. Complementary live-trap survey methods were employed for sampling small non-volant mammals and transects along roads for medium and large mammals. Seventeen mammalian species were recorded, with five new records for Sergipe state, two being endemic to Caatinga. More individuals were captured in the dry season, although species number was the same for both seasons. Medium- and large-sized mammalian species were not encountered in the region, which was also true for some small-sized species hunted for consumption. These findings corroborate the importance of using complementary methods for sampling small non-volant mammals in the Caatinga and indicate that the mammalian fauna of this region, suffering a severe anthropogenic pressure, requires strong measures for its preservation.

Pequenos mamíferos não-voadores (Didelphimorphia, Rodentia) em campos litorâneos do extremo sul do Brasil

Non-volant small mammals are key elements in natural environments due its importance as food resource. This study aimed to investigate the species composition and habitat occupancy by non-volant small mammals (Didelphimorphia, Rodentia) in a coastal grassland area in southern Rio Grande do Sul coastal plain. Between April 2009 and March 2010 pitffal traps were used to capture small mammals in coastal grasslands associated to sand dunes and arbustive Restinga. We sampled 180 individuals including two marsupials (Cryptonanus guahybae and Didelphis albiventris) and seven rodent species (Calomys laucha, Cavia aperea, Ctenomys flamarioni, Deltamys kempi, Oligoryzomys flavescens, Oxymycterus nasutus and Scapteromys tumidus). Cryptonanus guahybae, D. albiventris and C. flamarioni were captured only in dunes while C. aperea and O. nasutus were recorded only in arbustive Restinga habitats. Calomys laucha, D. kempi, O. flavescens and O. nasutus were captured in both habitats. Oligoryzomys flavescens and C. laucha were the most representative species in both habitats, comprising respectively 40.7 and 38.9% of captures in dunes and 56.3 and 34.9% of captures in Restinga habitats. The species richness recorded in the sampled coastal grasslands area was lower than those previously recorded in subtropical forest coastal systems.

Mammals of a forest fragment in Cambuci municipality, state of Rio de Janeiro, Brazil

The Atlantic Forest is considered a hotspot due to its current state of vast degradation and high indexes of biodiversity. This biome has been degraded through the years by processes resulting from the Brazilian socioeconomic model of development. The seasonal semi-deciduous Atlantic Forest is a poorly studied phytophysiognomy specially degraded by human activities in the state of Rio de Janeiro. In the present study we report the results of a rapid mammalian inventory conducted in the municipality of Cambuci, in a fragment of seasonal semi-deciduous forest. We used live traps and pitfall traps to capture non-volant small mammals, and mist-nets of different lengths to collect bats. To sample medium and large-sized mammals we used camera traps. We recorded 27 mammal species in the region, of which 16 are volant mammals. We emphasize the distribution extension of Trinomys setosus in 150 km (that enabled its insertion in the species list of Rio de Janeiro) and the capture of Lonchophylla peracchii, a recently described species apparently restricted to Atlantic Forest. Both facts show the importance of the fragment for the region biodiversity.

Non-volant small mammals at an Atlantic forest area situated nearby a limestone quarry (Limeira quarry), state of São Paulo, Brazil

Our aim was to survey the non-flying small mammals inhabiting an Atlantic forest area situated nearby a limestone quarry (Limeira quarry), located at Ribeirão Grande municipality (SP), southeastern Brazil. Species were captured with pitfall and Sherman traps along eight pairs of 60 m transects distributed at four different distances from the quarry (60, 220, 740 and 1300 m). Between October 2005 and January 2008, 20 small mammal species (11 rodents and nine marsupials) were captured through 4080 pitfall trap-nights and 2040 Sherman trap-nights. The high values of richness, diversity (H' = 2.65) and equability (J = 0.88), and the presence of endemic and threatened species indicates a preserved study site and small mammal assemblage. Marmosops incanus, Monodelphis americana and Oligoryzomys nigripes were the commonest species at the study site. Trapping sites located closer to the quarry (60 and 220 m away from the quarry) presented lower richness and were dominated by disturbance-tolerant species, such as O. nigripes, that usually benefit from habitat alterations. On the other hand, sites located away from the quarry and closer to Serra do Mar Protected Area (740 and 1300 m away from the quarry) presented higher richness and diversity, and a higher abundance of disturbance-intolerant species. These results suggest a negative distance-dependent impact of quarrying on small mammal communities. In this way, our results point out to the importance of long-term monitoring of quarrying impacts on small non-flying mammal communities and populations, and the need of conservation strategies in order to ensure species persistence in these areas.

Faunal nestedness and species–area relationship for small non-volant mammals in “sky islands” of northern Venezuela

We study the biogeography of small non-volant mammals in mesic montane sky islands of northern Venezuela. Fieldwork, examination of museum specimens, and critical use of literature yielded species lists for the Cordillera de Mérida, Cordillera de la Costa, Serranía de San Luis, and Cerro Santa Ana. Fieldwork confirmed the species known from Cerro Santa Ana and added 12 species for the Serranía de San Luis. Richness decreases with smaller area. Furthermore, the faunas are highly nested, with taxa dropping out at successive depressions. Species deviating from nestedness provide a signal indicative of in situ speciation in rodents but not in marsupials.

Elevational Rapoport's rule is not pervasive on mountains

Aim Elevational Rapoport’s rule, proposed in 1992 by Stevens, predicts that species ranges on mountains become larger in elevational extent with increasing elevation. Here we test this prediction using 160 datasets of range size measured by maximum elevational extents for bats, birds, frogs, non-volant small mammals, reptiles, and salamanders from mountains around the globe.

Use of habitats by non-volant small mammals in Cerrado in Central Brazil

Non-volant small mammals are organisms capable of yielding precise information on richness, abundance and species composition variations related to the use of habitats. The aim of this research was to compare these variations in Cerrado sensu stricto, Palm Forest, Gallery Forest and Rocky Field. From May 1999 to February 2000, we surveyed non-volant small mammals (hence small mammals) in Serra das Araras Ecological Station. We captured 218 individuals and recaptured 62 individuals, belonging to 21 taxa, 13 rodents and eight marsupials, in a total of 13200 trap-nights. Capture success was 1.7%. We observed higher richness of small mammals in forested areas (Gallery Forest and Palm Forest) than in open areas (Rocky Field and Cerrado sensu stricto). The Palm Forest had the highest richness of marsupials, possibly due to the quality of a specific niche. The Rocky Field had the smallest richness, but with very high abundance of few species, mainly Thrichomys pachyurus and Monodelphis domestica. Forest habitats had similar species composition. The open habitats, Cerrado sensu stricto and Rocky Field, had a distinct species composition between them, and also when compared to forested areas. Different species are exclusive or showed preference for specific habitats. The protection of horizontally heterogeneous biomes, such as Cerrado, has a fundamental importance to the maintenance of the regional diversity of the small mammal community of Central Brazil.

Preliminary inventory of mammals from Yurubí National Park, Yaracuy, Venezuela with some comments on their natural history.

In Venezuela, mammals represent an important group of wildlife with high anthropogenic pressures that threaten their permanence. Focused on the need to generate baseline information that allows us to contribute to document and conserve the richness of local wildlife, we conducted a mammalogical inventory in Yurubí National Park, located in Yaracuy State in Venezuela. We carried out fieldworks in three selected vegetation types: an evergreen forest at 197m, a semi-deciduous forest ranging between 100-230m, and a cloud forest at 1 446m. We used Victor, Sherman, Havahart and pitfall traps for the capture of small non-volant mammals and mist nets for bats. In addition, we carried out interviews with local residents and direct-indirect observations for medium-large sized mammals. At least 79 species inhabit the area, representing 28% of the species recorded for the North side of the country. Chiroptera (39 spp.), Carnivora (13 spp.) and Rodentia (9 spp.) were the orders with the highest richness, as expected for the Neotropics. The evergreen forest had the greatest species richness (n=68), with a sampling effort of 128 net-hours, 32 bucket-days, 16 hours of observations, and three persons interviewed, followed by cloud forest (n=45) with 324 net-hours, 790 traps-night, 77 bucket-days, 10 hours of observations, and one person interviewed. The lowest richness value was in the semi-deciduous forest (n=41), with 591 traps-night, 15 net-hours, 10 hours of observations and three persons interviewed. Data and observations obtained in this inventory (e.g., endemism, species known as "surrogate species" threatened in Venezuela) give an important role at the Yurubí National Park in the maintenance and conservation of local ecosystems and wildlife, threatened by human pressures in the Cordillera de la Costa.

Inferring host specificity and network formation through agent-based models: tick–mammal interactions in Borneo

Patterns of host-parasite association are poorly understood in tropical forests. While we typically observe only snapshots of the diverse assemblages and interactions under variable conditions, there is a desire to make inferences about prevalence and host-specificity patterns. We studied the interaction of ticks with non-volant small mammals in forests of Borneo. We inferred the probability of species interactions from individual-level data in a multi-level Bayesian model that incorporated environmental covariates and advanced estimates for rarely observed species through model averaging. We estimated the likelihood of observing particular interaction frequencies under field conditions and a scenario of exhaustive sampling and examined the consequences for inferring host specificity. We recorded a total of 13 different tick species belonging to the five genera Amblyomma, Dermacentor, Haemaphysalis, Ixodes, and Rhipicephalus from a total of 37 different host species (Rodentia, Scandentia, Carnivora, Soricidae) on 237 out of 1,444 host individuals. Infestation probabilities revealed most variation across host species but less variation across tick species with three common rat and two tree shrew species being most heavily infested. Host species identity explained ca. 75 % of the variation in infestation probability and another 8-10 % was explained by local host abundance. Host traits and site-specific attributes had little explanatory power. Host specificity was estimated to be similarly low for all tick species, which were all likely to infest 34-37 host species if exhaustively sampled. By taking into consideration the hierarchical organization of individual interactions that may take place under variable conditions and that shape host-parasite networks, we can discern uncertainty and sampling bias from true interaction frequencies, whereas network attributes derived from observed values may lead to highly misleading results. Multi-level approaches may help to move this field towards inferential approaches for understanding mechanisms that shape the strength and dynamics in ecological networks.

Edge effects and the impact of wildfires on populations of small non-volant mammals in the forest-savanna transition zone in Southern Amazonia

The impact of fire and edge effects on the community of small non-volant mammals was investigated in transitional Amazon forest within a matrix of soybean plantations. The animals were live trapped on 24 line transects, of which 16 were distributed in unburned areas and 8 in a burned area. A total of 11 species was recorded, including six rodents and five marsupials. The abundance and richness of small mammals appeared to decrease in burned areas, although this impact appeared to mask edge effects. In the absence of fire impacts, a positive relationship was found between mammal abundance and the distance from the forest edge. The impact of the edge effect on the diversity of small mammals appears to be influenced by the type of anthropogenic matrix and the ecological characteristics of the different species.

Terrestrial non-volant small mammals in agro-silvicultural landscapes of Southeastern Brazil

The area covered by Eucalyptus plantations is significantly increasing in Brazil for economic reasons. However, the impact of such land use change is still unknown. In this study we evaluated the spatial–temporal distribution and abundance of terrestrial non-volant small mammals on a recently converted landscape whose matrix is formed by Eucalyptus plantations up to 3years of age. From August 2007 to July 2009 we carried out monthly sampling campaigns over a grid of 30 sampling units, formed by pitfall traps covering both the landscape matrix of Eucalyptus plantations (n=18) and legal conservation areas of native vegetation (n=7) and abandoned pastures (n=5). A total of 1640 individuals from 14 species of the orders Didelphimorphia (4 spp.) and Rodentia (10 spp.) were captured. However, only three species of rodents (Olygorysomys flavescens, Oligoryzomys nigripes and Calomy tener) represented 81.8% of the total amount. Eucalyptus plantations had a lower species richness and abundance than the abandoned pasture and the remaining fragments of native vegetation. Although the present species are predominantly generalists, there is clear distinction among environments in terms of their species composition and relative abundance, which also present a pronounced time variation. The assemblage found in this study suggests that silvicultural landscapes still have some conservation value, with species that seem to be resident at the Eucalyptus plantations. Moreover, the presence of the native and abandoned pastures patches imbibed in the Eucalyptus plantation matrix may increase the carrying capacity of such a silvicultural system and these landscapes may play a role in maintaining local biodiversity.

Pequenos mamíferos não-voadores (Didelphimorphia, Rodentia) em dois fragmentos de mata de restinga de Rio Grande, planície costeira do Rio Grande do Sul

As matas de restinga representam formações vegetais originais na Planície Costeira do estado do Rio Grande do Sul. O objetivo deste trabalho foi avaliar a composição de espécies de pequenos mamíferos não-voadores em dois fragmentos de matas de restinga (mata palustre e mata arenosa ciliar) no município de Rio Grande, região sul da Planície Costeira do Rio Grande do Sul. Um total de 234 indivíduos pertencentes a três espécies de marsupiais (Didelphidae: Cryptonanus guahybae, Didelphis albiventris, Lutreolina crassicaudata) e oito espécies de roedores (Cricetidae: Deltamys kempi, Holochilus brasiliensis, Oligoryzomys flavescens, O. nigripes, Oxymycterus nasutus, Scapteromys tumidus; Muridae: Mus musculus, Rattus rattus) foi capturado. As espécies C. guahybae, D. albiventris, D. kempi, H. brasiliensis, O. nigripes, S. tumidus e M. musculus foram registradas no fragmento de mata palustre, enquanto que C. guahybae, D. albiventris, Lutreolina crassicaudata, D. kempi, O. flavescens, O. nigripes, S. tumidus e R. rattus ocorreram no fragmento de mata arenosa ciliar. Oligoryzomys nigripes e S. tumidus foram as espécies mais abundantes no fragmento de mata palustre, representando respectivamente 40,4 e 22,1% do total de indivíduos capturados. No fragmento de mata arenosa ciliar, as espécies mais abundantes foram O. nigripes e D. albiventris, representando respectivamente 63,4 e 12,4% do total de indivíduos capturados. Indivíduos de C. guahybae e O. nigripes foram capturados em estrato arbóreo (alturas entre 0,50 e 1,65 m) enquanto que todos os indivíduos das demais espécies foram capturados no solo.

Ecological implications on the aggregation of Amblyomma fuscum (Acari: Ixodidae) on Thrichomys laurentius (Rodentia: Echimyidae), in northeastern Brazil

We investigated the Amblyomma fuscum load on a pullulating wild rodent population and the environmental and biological factors influencing the tick load on the hosts. One hundred and three individuals of Thrichomys laurentius were caught in an Atlantic forest fragment in northeastern Brazil, as part of a longitudinal survey on ticks infesting non-volant small mammals. Ticks (n = 342) were found on 45 individuals and the overall mean intensity of infestation was 7.6 ticks per infested rodent. Ticks were highly aggregated in the host population and the negative binomial distribution model provides a statistically satisfactory fit. The aggregated distribution was influenced by sex and age of the host. The microhabitat preference by T. laurentius probably increases contact opportunities between hosts and aggregated infesting stages of the ticks and represents important clues about the habitat suitability for A. fuscum.

贡嘎山东坡非飞行小型兽类物种多样性的垂直分布格局

To understand the species diversity distribution pattern of Gongga Mountain,we surveyed the diversity of non-volant small mammals along the elevational gradient on the eastern slope of Gongga Mountain from April to September in 2010.Eight sampling sites were set along the elevational gradient from 1200m to 4000m with an interval of 400m,and 701 small mammals were captured in 28800 trap nights.Plusing the 25 field observed squirrels,our study surveyed totally 726 individuals representing 25 species that were belong to 16 genera,6 families and 3 orders.The two non-parametric estimations of species richness Chao2 and Jackknife2 as well as the species cumulative curve demonstrated that the sampling of non-volant small mammal species were adequate and well reflected the diversity distribution pattern along the elevational gradient.The results showed that the species richness and abundance patterns for non-volant small mammals along the eastern slope of Gongga Mountain were hump-shaped with the highest richness at mid-elevation,but decreased at both lower and higher elevations.In contrast,species evenness displayed a distribution pattern with high evenness at high and low elevations but low evenness at mid-elevation,whereas species dominance index increased gradually along the elevational gradient.Four widely-used diversity indices(Shannon-Wiener,Simpson,Fisher-α and Margalef) were used to compare the diversity discrepancy between different elevational communities and also used to reveal the diversity distribution pattern.The Fisher-α and Margalef diversity indices seemed to reveal the diversity discrepancy between different communities much better than the Shannon-Wiener and Simpson diversity indices.Meanwhile,Simpson diversity index failed to reflect the unimodal distribution pattern of diversity along the gradient.The elevational distribution patterns of the diversity indices showed the same distribution pattern as the species richness and abundance with peaks at the mid-elevation.This result was also supported by clustering analysis based on the species composition of the 8 elevational bands.This unimodal diversity distribution pattern suggests that the mid-elevational area should be paid more attention in the diversity conservation and ecological management of Gongga Mountain,because it harbors the highest diversity of small mammals and these irreplaceable species play important and fundamental roles in maintaining the health of mountain ecosystems.Furthermore,standard and unified sampling methods could be contributive to the integration of research data so as to reduce any artificial errors from different diversity investigation methods.

A survey of small non-volant mammals inhabiting Wayampi Amerindian houses in French Guiana

The commensal small non-volant mammals found in tradi-tional houses of Wayampi Amerindians have been studied in villages of Trois-Sauts on the upper Oyapock River (French Guiana). The Wayampi, also called Oyampi, are Amerindians living traditional lifestyles in the southeastern part of the Guianan Shield, especially in the Oyapock basin of French Guiana and in the Amapari basin of northernmost Brazil (Amapa) (Grenand et al. 1999 ). Today, many Wayampi live in close contact with modern occidental people, but a group of ca. 600 people (2010 census) remains relatively isolated on the upper Oyapock River. In particular, the Trois-Sauts com-munity, spaced along ca. 30 km on the left bank of the upper Oyapock, is still made up of hunters and gatherers who also tend small garden plots (Ouhoud-Renoux 1998)

Chapter 3: The Mammals of the Mingan Mountains, Luzon: Evidence for a New Center of Mammalian Endemism

We conducted an elevational transect survey of mammals on the highest peak in the Mingan Mountains of Aurora and Nueva Ecija provinces in the central Sierra Madre Range of Luzon from May to August 2006 and documented 35 species of mammals. These included one shrew (Soricidae), six fruit bats (Pteropodidae), one ghost bat (Megadermatidae), three horseshoe bats (Rhinolophidae), three roundleaf bats (Hipposideridae), four evening bats (Vespertilionidae), one macaque (Cercopithecidae), 12 mice and rats (Muridae), two civets (Viverridae), one wild pig (Suidae), and one deer (Cervidae). Our survey of this small, poorly known mountain range included the discovery of two new species of forest mice (Apomys), a new species of shrew-mouse (Archboldomys), a probable new species of shrew-rat (Rhynchomys), and an unidentified species of tube-nosed bat (Murina). Species richness of bats decreased with increasing elevation, whereas that for native non-volant small mammals increased with increasing elevation up to 1677 m, then declined at 1681 and 1785 m. Statistically significant diel activity and bait preferences were observed among the native non-volant small mammals. Only the two species of small forest mice (Apomys microdon and A. musculus) were captured exclusively above ground; the other non-volant small mammals were nearly always captured on the ground. The Mingan Mountains, with either three or four endemic species, are clearly a significant center of mammalian endemism, deserving of conservation.

Chapter 2: Mammalian Diversity Patterns on Mount Palali, Caraballo Mountains, Luzon

Abstract In 2005 and 2007, we conducted surveys of mammals along an elevational transect on Mount Palali (peak 1707 m) in the Caraballo Mountains, a poorly known mountain range on Luzon Island, Philippines. The surveys covered eight localities representing habitats from lowland agroforest and regenerating disturbed lowland rainforest at 780 m to mossy forest near the peak. We recorded 24 species, including one native shrew, one non-native shrew, five fruit bats, seven insectivorous bats, one monkey, six native rodents, two civets, and one pig. One species of Apomys is the newly described A. sierrae, and two species of Chrotomys are potentially undescribed species. Elevational patterns varied among mammals: bats were most diverse in the lowlands, native nonvolant small mammals had almost equal richness along the entire elevational transect, and most species of large mammals were present at all elevations. Bait attractiveness and diel activity pattern differed among native nonvolant small mammals: Apomys mi...