Small Marsupials Research Articles

Tropical savanna small mammals respond to loss of cover following disturbance: A global review of field studies

Small-mammal faunas of tropical savannas consist of endemic assemblages of murid rodents, small marsupials, and insectivores on four continents. Small mammals in tropical savannas are understudied compared to other tropical habitats and other taxonomic groups (e.g., Afrotropical megafauna or Neotropical rainforest mammals). Their importance as prey, ecosystem engineers, disease reservoirs, and declining members of endemic biodiversity in tropical savannas compels us to understand the factors that regulate their abundance and diversity. We reviewed field studies published in the last 35 years that examined, mostly experimentally, the effects of varying three primary endogenous disturbances in tropical savanna ecosystems—fire, large mammalian herbivory (LMH), and drought—on abundance and diversity of non-volant small mammals. These disturbances are most likely to affect habitat structure (cover or concealment), food availability, or both, for ground-dwelling small mammalian herbivores, omnivores, and insectivores. Of 63 studies (included in 55 published papers) meeting these criteria from the Afrotropics, Neotropics, and northern Australia (none was found from southern Asia), 29 studies concluded that small mammals responded (mostly negatively) to a loss of cover (mostly from LMH and fire); four found evidence of increased predation on small mammals in lower-cover treatments (e.g., grazed or burned). Eighteen studies concluded a combination of food- and cover-limitation explained small-mammal responses to endogenous disturbances. Only two studies concluded small-mammal declines in response to habitat-altering disturbance were caused by food limitation and not related to cover reduction. Evidence to date indicates that abundance and richness of small savanna mammals, in general (with important exceptions), is enhanced by vegetative cover (especially tall grass, but sometimes shrub cover) as refugia for these prey species amid a “landscape of fear,” particularly for diurnal, non-cursorial, and non-fossorial species. These species have been called “decreasers” in response to cover reduction, whereas a minority of small-mammal species have been shown to be “increasers” or disturbance-tolerant. Complex relationships between endogenous disturbances and small-mammal food resources are important secondary factors, but only six studies manipulated or measured food resources simultaneous to habitat manipulations. While more such studies are needed, designing effective ones for cryptic consumer communities of omnivorous dietary opportunists is a significant challenge.

Small Alpine Marsupials Regulate Evaporative Water Loss, Suggesting a Thermoregulatory Role Rather than a Water Conservation Role.

AbstractWe show here that evaporative water loss (EWL) is constant over a wide range of ambient relative humidity for two species of small, mesic habitat dasyurid marsupials (Antechinus agilis and Antechinus swainsonii) below thermoneutrality (20°C) and within thermoneutrality (30°C). This independence of EWL from the water vapor pressure deficit between the animal and its environment indicates that EWL is physiologically controlled by both species. The magnitude of this control of EWL was similar to that of two other small marsupials from more arid habitats, which combined with the observation that there were no effects of relative humidity on body temperature or metabolic rate, suggests that control of EWL is a consequence of precise thermoregulation to maintain heat balance rather than a water-conserving strategy at low relative humidities. The antechinus appear to manipulate cutaneous EWL rather than respiratory EWL to control their total EWL by modifying their cutaneous resistance and/or skin temperature. We propose that there is a continuum between enhanced thermoregulatory EWL at high ambient temperature and so-called insensible EWL at and below thermoneutrality.

Predicting mammal responses to pyrodiversity: From microbats to macropods

Fire has shaped Australia's diverse mammal fauna for millennia. However, ongoing changes to fire regimes threaten native mammal populations, and a significant conservation challenge is to understand and promote desirable forms of pyrodiversity (variation in fire regimes). A way forward is to quantify how different aspects of pyrodiversity influence whole mammal assemblages and produce dynamic maps of species distributions to inform conservation. We aimed to determine and map how spatial and temporal variation in fire regimes correlates with a diverse mammal assemblage comprising macropods, microbats, rodents, small marsupials and a monotreme. We built species distribution models for 17 species against fire, climate and environmental covariates in fire-prone woodlands of semi-arid Australia. Spatial measures of fire included the area, diversity and configuration of landscape elements, and temporal measures included time since fire and fire frequency. Native mammals showed a variety of responses to pyrodiversity. Microbats were more likely to occur as time since fire increased, whereas rodents were correlated with recently burned areas. Small dasyurid marsupials were correlated with the area of older post-fire age-classes, while western grey kangaroo occurrence was positively associated with high diversity of post-fire ages. Our new approach, using predictive models to map mammal distributions in relation to spatial and temporal variation in fire regimes, provides outputs that managers can use to improve conservation planning. This enables the positive and negative effects of fire to be better understood and will assist in achieving desirable forms of pyrodiversity that meet the needs of whole mammal assemblages.

Taxonomic review of the slender mouse opossums of the "Parvidens" group from Brazil (Didelphimorphia: Didelphidae: Marmosops), with description of a new species.

The genus Marmosops comprises small marsupials of the family Didelphidae (≤ 200 g), widely distributed in a variety of lowland rainforest and montane forest habitats, extending from Panama to southern Bolivia and southeastern Brazil. The smallest species of the genus are included in the "Parvidens" group, which includes M. pakaraimae, M. parvidens and M. pinheiroi. Although the monophyly of this group and species relationships are well defined, molecular studies have indicated that M. pinheiroi may represent a species complex, which has never been tested based on morphological analysis. In this study, we present the taxonomic review of M. pinheiroi based on the largest sample ever analyzed of this species. The external and craniodental morphology of 613 specimens of M. parvidens and M. pinheiroi from the northern, eastern, central and southern Brazilian Amazonia and northern Cerrado were examined. Besides, 28 craniodental dimensions were measured from adult specimens to support univariate and multivariate statistical analyses. Our results corroborate the validity of M. parvidens and indicate that M. pinheiroi is a complex formed by three species - M. pinheiroi (s. s.), distributed to the north of the Amazon River, from eastern Venezuela to the state of Amapá in Brazil; M. woodalli, which occurs east of the Xingu river and in the Marajó Island, state of Pará, extending to the east in the states of Tocantins and Maranhão; and a new species that occurs from the left bank of the Madeira River to the left bank of the Xingu River, herein described. Although the great morphometric similarity, species of the M. pinheiroi complex tended to be more different from each other than to M. parvidens in both univariate and multivariate analyses. Morphologically, these species may be positively distinguished by unique combinations of characters, such as dorsal and ventral fur coloration, arrangement of gray based hairs on the venter, supraoccipital shape, development of anterior and posterior portions of the M3 stylar shelf, continuity or not between the preprotocrista and anterior labial cingulum along the anterior margin of the upper molars, development of the metaconule in the upper molars, and number of cusps of the m4 talonid. The present work provides new perspectives for studies based on molecular data in order to test the species hypotheses recognized here and evaluate to what extent the Tapajós, Madeira, and Araguaia-Tocantins rivers actually isolate Marmosops populations.

A burning question: what are the risks and benefits of mammalian torpor during and after fires?

Although wildfires are increasing globally, available information on how mammals respond behaviourally and physiologically to fires is scant. Despite a large number of ecological studies, often examining animal diversity and abundance before and after fires, the reasons as to why some species perform better than others remain obscure. We examine how especially small mammals, which generally have high rates of energy expenditure and food requirements, deal with fires and post-fire conditions. We evaluate whether mammalian torpor, characterised by substantial reductions in body temperature, metabolic rate and water loss, plays a functional role in survival of mammals impacted by fires. Importantly, torpor permits small mammals to reduce their activity and foraging, and to survive on limited food. Torpid small mammals (marsupials and bats) can respond to smoke and arouse from torpor, which provides them with the possibility to evade direct exposure to fire, although their response is often slowed when ambient temperature is low. Post-fire conditions increase expression of torpor with a concomitant decrease in activity for free-ranging echidnas and small forest-dwelling marsupials, in response to reduced cover and reduced availability of terrestrial insects. Presence of charcoal and ash increases torpor use by captive small marsupials beyond food restriction alone, likely in anticipation of detrimental post-fire conditions. Interestingly, although volant bats use torpor on every day after fires, they respond by decreasing torpor duration, and increasing activity, perhaps because of the decrease in clutter and increase in foraging opportunities due to an increase in aerial insects. Our summary shows that torpor is an important tool for post-fire survival and, although the physiological and behavioural responses of small mammals to fire are complex, they seem to reflect energetic requirements and mode of foraging. We make recommendations on the conditions during management burns that are least likely to impact heterothermic mammals.

Charred remains trigger torpor in antechinus survivors

![Figure][1] A yellow footed antechinus, Antechinus flavipes . Photo credit: Clare Stawski. Few creatures can outrun a forest fire as it engulfs everything in its path. For small marsupials, such as fat-tailed dunnarts and yellow-footed antechinus, the best hope is to nestle deep down in

Marsupials don't adjust their thermal energetics for life in an alpine environment

ABSTRACTMarsupials have relatively low body temperatures and metabolic rates, and are therefore considered to be maladapted for life in cold habitats such as alpine environments. We compared body temperature, energetics and water loss as a function of ambient temperature for 4 Antechinus species, 2 from alpine habitats and 2 from low altitude habitats. Our results show that body temperature, metabolic rate, evaporative water loss, thermal conductance and relative water economy are markedly influenced by ambient temperature for each species, as expected for endothermic mammals. However, despite some species and individual differences, habitat (alpine vs non-alpine) does not affect any of these physiological variables, which are consistent with those for other marsupials. Our study suggests that at least under the environmental conditions experienced on the Australian continent, life in an alpine habitat does not require major physiological adjustments by small marsupials and that they are physiologically equipped to deal with sub-zero temperatures and winter snow cover.

Spatiotemporal diversification of a low‐vagility Neotropical vertebrate clade (short‐tailed opossums, Didelphidae: Monodelphis)

AbstractAimTo infer historical‐biogeographical patterns and processes in South America based on estimated divergence times and ancestral distributions for a diverse clade of small marsupials (Monodelphis).LocationSouth America.MethodsWe estimated a time‐scaled phylogeny using sequence data from four nuclear genes and one mitochondrial gene for most currently recognized species, which we also scored for biome occupancy. We used maximum‐likelihood methods that explicitly model historical‐biogeographical processes to estimate ancestral distributions.ResultsThe earliest cladogenetic events in the genus occurred in the late Miocene, with subsequent diversification from the early Pliocene to the late Pleistocene. Model selection suggests an important role for founder‐event speciation, a process seldom accounted for in previous biogeographical analyses of continental clades. Two equivalently optimal models that incorporate this process each reconstruct the most recent common ancestor of Monodelphis as occurring in both Amazonia and the Atlantic Forest, from which the Andes, the Arid Diagonal (Caatinga, Cerrado, Chaco) and other neighbouring biomes were colonized during the Pliocene and Pleistocene.Main ConclusionsThe diversification of Monodelphis was not restricted to a narrow time interval, suggesting that speciation cannot be attributed to a single leading factor such as tectonism or Pleistocene climatic fluctuations. In particular, speciation within the Atlantic Forest biome appears to have occurred in the Neogene, whereas most Amazonian speciation events are substantially younger. Amazonia and/or the Atlantic Forest hosted most diversification events within Monodelphis and were the historical sources of lineages that subsequently colonized other areas. Founder‐event speciation, a concept traditionally associated with long‐distance dispersal among islands, must sustain other interpretations in historical‐biogeographical analyses of non‐vagile organisms in continental contexts. Possible mechanisms for founder‐event speciation in Monodelphis include historically transient connections between currently disjunct biomes and rapid reproductive isolation of populations colonizing adjacent but ecologically disparate biomes.

Timing and environmental cues associated with triggering of reproductive activity in Atlantic forest marsupials

Seasonal reproduction during the time when food availability is high is a widespread strategy in marsupials, which maximizes offspring survival. In Australian marsupials, reproduction is commonly synchronous among co-occurring species, the onset of reproduction being triggered by photoperiodic cues. In a subset of these species, partial semelparity with high mortality of males after reproduction is a common pattern. For Neotropical marsupials, however, environmental triggers of reproduction have been poorly studied despite some evidence of a seasonal synchronous reproduction, and semelparity has been described in few species. Using a capture–recapture dataset of co-occurring marsupials in the Atlantic forest sampled for two years, we aim to investigate the timing and triggering of reproductive activity as well as the occurrence of semelparity in Neotropical small marsupials. We evaluated which environmental cues (rainfall, photoperiod and temperature) best explain the age structure of the populations of Gracilinanus microtarsus, Marmosops incanus, Marmosops paulensis, Monodelphis americana, Monodelphis scalops and Monodelphis iheringi. For the most common species we also tested for the occurrence of semelparity by assessing if survival rate is affected by sex and mating period. Our results indicate that reproduction onset seems to be synchronous among species and driven by photoperiod cues. In all species, reproduction is seasonal with juveniles being born and lactation occurring in the period of highest food availability, the warm–wet season. Further, semelparity is likely to be the cause of a high population turnover in Marmosops incanus, and probably also in co-occurring marsupials.

Micromamíferos, cambio climático e impacto antrópico: ¿Cuánto han cambiado las comunidades del sur de América del Sur en los últimos 500 años?

Introduction: The last 500 years of the historical era, an interval that corresponds to the concerted dispersal of European explorers, traders, and colonists around the globe, has witnessed the global disappearance of ~90 mammal species. Besides the known cases of biological extinctions, this time period was also characterized by the regional extirpations of specialized taxa and by the expansion and population growth of some opportunistic species. Several lines of evidence suggest that the current configuration of small mammal communities - i. e . richness (number of species) and diversity (distribution of species abundance)- in southern South America would have been generated in the period after the arrival of Europeans ca . 1500 AD. In this study, we reviewed the fossil record for small rodents and marsupials during the last 500 years, with emphasis on the Pampean and Patagonian regions. Based on these findings, we offer some considerations concerning the biogeography and conservation of these species. Methods: Micromammals from archaeological and paleontological sites have provided considerable information on environmental conditions during the Quaternary in South America. In this work, we reviewed several micromammal fossil samples, mostly generated by the trophic activity of owls. The use of this kind of data involves some extrinsic and intrinsic biases that must be considered at the time to study the diversity of past communities, such as the bird involved on the accumulations, its hunting techniques, the time of the year, the size and behavior of the prey species, etc. For this work, we compared the fossil samples with more than 700 owl pellet assemblages of the same geographical areas. Results: Richness and diversity of small mammal communities was higher prior to the deepest human impact (> 0.5 ka), showing a pronounced drop in both parameters to the present. The regional extinction of some cricetid rodents and small marsupials was recorded, both in the Pampean ( e. g. Bibimys torresi , Pseudoryzomys simplex ) and in the Patagonian regions ( e . g . Euneomys mordax, Lestodelphys halli, Tympanoctomys kirchnerorum ), as well as the biological extinctions of the bat Desmodus cf. D . draculae and the cavy Galea tixiensis in the Pampas. At this same time, opportunistic species ( e. g. Calomys spp., Oligoryzomys longicaudatus ) showed a dramatic increase of their populations, especially in the most extensively disturbed areas. Discussion and conclusions: In the last 500 years, significant variations occurred in the micromammal assemblages of southern South America. These changes included the dispersion and increase (in some cases extensive) of some specialized species and the regional extinctions of others, involving hundreds to thousands of kilometers of distributional extent. We suggest that the changes produced by livestock and agriculture have caused extensive habitat uniformity which was beneficial for some opportunistic taxa ( e. g . Calomys spp., Oligoryzomys longicaudatus ), facilitating their dispersion and allowing the increase of their populations. Anthropic disturbances also include the extensive use of fire, urbanization, and introduction of exotic forbs and grasses. Of about 46 species rodents considered as Least Concern by the IUCN and with fossil record for the last 500 years, 23 (50 %) have experienced drastic reductions in their range or abundance during the Late Holocene. At least nine taxa are completely extinct, including one marsupial, one bat and seven rodents. Similar phenomena are recorded in other areas of the Southern Hemisphere, both in continental and island contexts. This evaluation of the fossil record highlights the need to evaluate more carefully the status of some species with supposedly stable populations, but which are likely to be affected by future extensive changes in their environments ( e. g . mining, expansion of the agricultural frontier). Key words: Argentina, Didelphimorphia, extinctions, small mammals, Rodentia, Sigmodontinae.

Developmental phenotypic plasticity in a marsupial

Climate change is likely to substantially affect the distribution ranges of species. However, little is known about how different mammalian taxa respond morphologically and physiologically to a rapid change of climate. Our objective was to provide the first quantitative data on the effect of continuous cold exposure during development on morphological and functional variables of a marsupial. Fat-tailed dunnarts (Sminthopsis crassicaudata, Dasyuridae) were reared at an ambient temperature (T(a)) of 16°C [cold-reared (CR)] or 22°C [warm-reared (WR)] until they reached adult age (>200 days). Body and head length of CR animals were significantly longer than in WR animals (mean ± s.e.m.; body: CR 80.8±6 mm, WR 76.4±5 mm; head: CR 29.4±3 mm, WR 27.5±2 mm), but other body attributes were not significantly different. Use of torpor was more frequent, torpor bout duration was longer and average daily metabolic rate and percentage of savings when using torpor were significantly higher (P<0.01) in CR than in WR animals at 16°C T(a) but not at 24°C. Furthermore, resting metabolic rates measured at 16°C T(a) were significantly lower in CR than WR animals; at 30°C T(a) values were similar. Our results do not conform to Allen's rule, but to some extent they do conform to Bergmann's rule. However, the data demonstrate that a relatively moderate cold exposure from birth until adulthood induces marked changes in the morphology and thermal energetics of small marsupials. Such short-term phenotypic responses without the need for long-term selection are likely important for the ability to cope with different climates over a wide range of distribution, but will also play a crucial role in enhancing the survival of species during climate change.

Muscle mitochondrial volume and aerobic capacity in a small marsupial (Sminthopsis crassicaudata) match those of 'athletic' placentals, reflecting flexible links between energy-use levels in mammals generally.

We investigated the muscle structure-function relationships that underlie the aerobic capacity of an insectivorous, small (~15 g) marsupial, Sminthopsis crassicaudata (Family: Dasyuridae), to obtain further insight into energy use patterns in marsupials relative to those in placentals, their sister clade within the Theria (advanced mammals). Disparate hopping marsupials (Suborder Macropodiformes), a kangaroo (Macropus rufus) and a rat-kangaroo (Bettongia penicillata), show aerobic capabilities as high as those of 'athletic' placentals. Equivalent muscle mitochondrial volumes and cardiovascular features support these capabilities. We examined S. crassicaudata to determine whether highly developed aerobic capabilities occur elsewhere in marsupials, rather than being restricted to the more recently evolved Macropodiformes. This was the case. Treadmill-trained S. crassicaudata attained a maximal aerobic metabolic rate ( or MMR) of 272 ml O2 min(-1) kg(-1) (N=8), similar to that reported for a small (~20 g), 'athletic' placental, Apodemus sylvaticus, 264 ml O2 min(-1) kg(-1). Hopping marsupials have comparable aerobic levels when body mass variation is considered. Sminthopsis crassicaudata has a basal metabolic rate (BMR) about 75% of placental values but it has a notably large factorial aerobic scope (fAS) of 13; elevated fAS also features in hopping marsupials. The of S. crassicaudata was supported by an elevated total muscle mitochondrial volume, which was largely achieved through high muscle mitochondrial volume densities, Vv(mt,f), the mean value being 14.0±1.33%. These data were considered in relation to energy use levels in mammals, particularly field metabolic rate (FMR). BMR is consistently lower in marsupials, but this is balanced by a high fAS, such that marsupial MMR matches that of placentals. However, FMR shows different mass relationships in the two clades, with the FMR of small (<125 g) marsupials, such as S. crassicaudata, being higher than that in comparably sized placentals, with the reverse applying for larger marsupials. The flexibility of energy output in marsupials provides explanations for this pattern. Overall, our data refute widely held notions of mechanistically closely linked relationships between body mass, BMR, FMR and MMR in mammals generally.

Standard Operating Procedures for aluminium box, wire cage, and pitfall trapping, handling, and temporary housing of small wild rodents and marsupials

Many researchers and educators need to provide Standard Operating Procedures (SOPs) to their Animal Ethics Committee (AEC) for the purpose of trapping, handling, and temporarily housing small mammals. We devised general SOPs that are compatible with most existing ones for Australia and had these SOPs reviewed by a panel of Australian experts. The SOPs may be used as guidelines by researchers who need to provide such protocols to their organisation or AEC, or in teaching.

Using A Priori Contrasts for Multivariate Repeated-Measures ANOVA to Analyze Thermoregulatory Responses of the Dibbler (Parantechinus apicalis; Marsupialia, Dasyuridae)

Physiological studies often involve the repeated measurement of individuals over a range of ordered categorical conditions, for example, varying ambient temperature. We illustrate here the use of a priori contrasts for multivariate repeated-measures ANOVA by analyzing the thermal responses of various physiological variables for a small marsupial, the dibbler (Parantechinus apicalis). Our analyses showed that dibblers conform closely to the Scholander-Irving model of endothermy. Body temperature was constant at low air temperatures, was 36.3 ± 0.24°C at thermoneutrality (30°C), and increased at 35°C. Metabolic rate decreased with increasing ambient temperature to a basal rate of 0.619 ± 0.036 mL O(2) g(-1) h(-1) at 30°C; it extrapolated closely to thermoneutral body temperature. Increased oxygen demand at lower ambient temperature was met by increased respiratory minute volume, achieved by increased respiratory frequency and tidal volume; oxygen extraction was constant at about 19%. Evaporative water loss and wet and dry thermal conductance increased markedly at high ambient temperatures but not sufficiently to maintain constant body temperature. Relative water economy was similar to that of other small marsupials, increasing linearly at lower air temperatures with a point of relative water economy of 20.3°C. We conclude that a priori contrasts provide a statistically appropriate and powerful analysis that can be used routinely to statistically describe the pattern of response of physiological variables to a categorical factor and are especially useful for repeated-measures ANOVA designs common to many physiological studies.

Cost, effort and outcome of mammal rediscovery: Neglect of small species

There is often intense public interest in the process of rediscovery of species that were presumed extinct, although rediscovered mammals are typically small, inconspicuous inhabitants of tropical forests. Conservation actions for small species are relatively inexpensive compared to the interventions required to protect charismatic, large mammals. However, threatened small mammals such as rodents, bats, shrews and small marsupials attract less research attention, conservation actions, space in zoos, and funding than larger species, and most threatened small mammals receive no attention, particularly those in tropical forest habitats. I investigated how the body size of rediscovered mammals has changed during the last century, how body size is associated with search and conservation effort and subsequent recovery, and the success of recovery actions for rediscovered mammals. There has been a strong decline in the mean body size of rediscovered mammals since the 19th century. Smaller species were missing for longer before rediscovery, and attracted less search effort. Cost estimates were lower in recovery plans for smaller rediscovered mammals. Despite this, increasing population trend after rediscovery was associated with larger body size, and larger species recovered better with conservation effort, although small species declined despite conservation effort. All species with no conservation actions (the majority of small species) were declining. Sixty percent of rediscovered mammals remain critically endangered or endangered, and 8% (6 species) are likely to be extinct. I argue that conservation outcomes for rediscovered mammals could be greatly improved by a modest increase in attention to small-bodied species.

Costs of Reproduction and Terminal Investment by Females in a Semelparous Marsupial

Evolutionary explanations for life history diversity are based on the idea of costs of reproduction, particularly on the concept of a trade-off between age-specific reproduction and parental survival, and between expenditure on current and future offspring. Such trade-offs are often difficult to detect in population studies of wild mammals. Terminal investment theory predicts that reproductive effort by older parents should increase, because individual offspring become more valuable to parents as the conflict between current versus potential future offspring declines with age. In order to demonstrate this phenomenon in females, there must be an increase in maternal expenditure on offspring with age, imposing a fitness cost on the mother. Clear evidence of both the expenditure and fitness cost components has rarely been found. In this study, we quantify costs of reproduction throughout the lifespan of female antechinuses. Antechinuses are nocturnal, insectivorous, forest-dwelling small (20–40 g) marsupials, which nest in tree hollows. They have a single synchronized mating season of around three weeks, which occurs on predictable dates each year in a population. Females produce only one litter per year. Unlike almost all other mammals, all males, and in the smaller species, most females are semelparous. We show that increased allocation to current reproduction reduces maternal survival, and that offspring growth and survival in the first breeding season is traded-off with performance of the second litter in iteroparous females. In iteroparous females, increased allocation to second litters is associated with severe weight loss in late lactation and post-lactation death of mothers, but increased offspring growth in late lactation and survival to weaning. These findings are consistent with terminal investment. Iteroparity did not increase lifetime reproductive success, indicating that terminal investment in the first breeding season at the expense of maternal survival (i.e. semelparity) is likely to be advantageous for females.

Use of space by the black-eared opossum Didelphis aurita in a rural area in southeastern Brazil

Habitat fragmentation is a process that modifies the structure of an original community, favouring species that are matrixtolerant and harming species that are continuous habitatdependent (Laurance et al. 2002). The use of space by animals in fragmented environments can be affected by the arrangement of areas of suitable habitat and by the ability of the individuals to move through areas that are different from the original habitat (Gascon et al. 1999, Passamani and Ribeiro 2009). The movements of an animal in space are governed by the availability of resources in the environment and by interactions between individuals (Brown and Orians 1970). Home range is the term used to refer to the area used by an individual for its common activities (Burt 1943), and it plays a central role in studies of space use by mammals. The area used by an individual during its daily activities, or the daily home range, is a space use measurement often used in studies with neotropical small marsupials and rodents analysed with the spool-and-line technique (Delciellos et al. 2006, Almeida et al. 2008, Vieira and Cunha 2008). The black-eared opossum Didelphis aurita (Wied-Neuwied, 1826) is a generalist and opportunist marsupial that can become abundant in fragmented environments in the absence of natural predators (Fonseca and Robinson 1990). It is nocturnal, solitary and omnivorous, and plays an important role in pioneer plant seed dispersion (Caceres and Monteiro-Filho 2000). In the southern part of the state of Minas Gerais, Brazil, the development of agricultural practices and urban centres has modified the original landscape in such a way that native vegetation habitat is found in small and fragmented patches. Due to the generalist and opportunist characteristics of D. aurita, it has apparently become abundant in the remaining forest patches of the region (Silva and Pas-

Bats and marsupials as indicators of endemism in the Yungas forest of Argentina.

Several studies have characterized the Yungas as a separate biogeographic unit, mainly based in floristic components. However, these characterizations were mainly qualitative and did not include faunal groups. The Yungas have been assumed as a region with rich floral and faunal diversity, but without testing how well they are described by animal distributions. Our study consists of a formal analysis of endemism based on distribution of small mammals in the southernmost portion of the Yungas. This area is biogeographically very interesting because the Yungas are comprised of discontinuous fragments of forests that extend into temperate arid and semiarid habitats. As a first approximation, we contrasted a group of volant species (bats) versus a group of non-volant species (marsupials). Our results show that small mammals are efficient indicators of endemism in Yungas. Eighty percent of the species of small marsupials included in the analysis supported the identified areas as being zones of endemism. Regarding bats, almost 55 percent of the species supported a designation of endemism. The results also show that the areas we considered are congruent with the botanical definition of the Yungas of northwestern Argentina and their subdivisions, an assumption that had not been previously tested with a formal quantitative method. We also found that non-volant species are better indicators of endemism than volant ones at regional scales, but volant species are better indicators than was previously thought.

Do implanted transmitters affect maximum running speed of two small marsupials?

Radiotelemetry is used to quantify behavioral, ecological, and physiological variables of animals. Because of technological limitations, relative transmitter size generally increases with decreasing body mass of the study animal, and the recommended transmitter mass of ,5% of body mass often prohibits work on small mammals. We compared burst running speed, important for predator avoidance, in 2 small marsupials, Sminthopsis crassicaudata (fat-tailed dunnart) and Planigale gilesi (Giles’ planigale), without and with implanted transmitters. In both species maximum running speed was not affected by the transmitters, whose mass ranged from 6.4% to 14.1% of body mass. Further, relative transmitter mass was not correlated with maximum running speed. Consequently, transmitters well above 5% of body mass need not affect locomotor performance of small terrestrial mammals. DOI: 10.1644/10-MAMM-A-052.1.

Food habits of the ocelot, Leopardus pardalis, in two areas in southeast Brazil

The objective of this study was to compare the diet of the ocelot at two sites in southeastern Brazil: the small (957 ha), isolated Caratinga Biological Station (CBS), Minas Gerais and the large (>44,000 ha) contiguous area, comprised of the Vale do Rio Doce Natural Reserve (VRDNR) and the Sooretama Biological Reserve (SBR). We collected 60 scats in CBS from January 1997 to July 2000. Small rodents, small marsupials and primates were the most important items in terms of frequency of occurrence. In terms of biomass consumed, the brown howler monkey (Alouatta guariba) was the most important item. In the VRDNR/SBR we collected 77 scats from April 1995 to September 1996 and from January 1999 to September 2000. The main food items were armadillo (Dasypus sp.), small rodents, teju (Tupinambis merianae), and small marsupials. In VRDNR/SBR the ocelot had a more diverse diet, probably reflecting the diversity of prey species found in this area. The occurrence of ocelots in CBS indicates the adaptive flexibility of this felid to forests fragments, probably facilitated by the high biomass of potential prey – in this case, the primate Alouatta guariba.