Volume 75, Issue 4

We tested the applicability of Allen’s rule in 47 species and 32 unnamed forms (populations that are probably good species or undefined taxa within a superspecies or species group) of the South American subterranean Hystricomorph rodents of the genus Ctenomys (tuco-tucos) (Rodentia: Ctenomyidae) by analyzing tail length in relation with head and body length, and body mass. Tail length allometry was analyzed by Reduced Major Axis regression while the possible correlation of relative tail length with temperature, precipitation and evapotranspiration variables was explored through Simultaneous Autoregression to account for spatial autocorrelations. Our results indicate that tuco-tucos do not follow Allen’s rule but its converse, tail proportion relative to body mass increasing with latitude while body size decreases in the same direction (the trend is similar for tail length relative to head and body length but not statistically significant). Regarding climatic variables, the main predictors of relative tail length were temperature and evapotranspiration variables with trends confirming the positive (non-Allenian) correlation of relative tail length with latitude. We conclude that tuco-tucos, being almost fully subterranean, thermoregulate behaviorally by maintaining constant temperatures within their burrows independent of geographic location. The former confirms previous results that indicated that Ctenomys follows the converse to Bergmann’s rule. Relative tail length variation would be a result of simple allometric growth.

Mast seeding is a common phenomenon in many plant species. It is widely believed to be an adaptive strategy for large-seeded plants to escape predation by small rodents. At population level, effects of mast seeding have been well investigated but studies at individual level are still rare. In this study, using semi-natural enclosures, we investigated the effects of seed availability (simulating mast seeding) on seed hoarding behaviors of the Siberian chipmunk Tamias sibiricus on Pinus koraiensis seeds in a temperate forest, northeastern China. We found that T. sibiricus per se tended to disperse and scatter-hoard more seeds of P. koraiensis when provided with high level of seeds. With increase of seed availability, the amount of seed consumption, cache size and seed dispersal distance, cache survival tended to be larger. Our results indicate that mast seeding can benefit seed dispersal and regeneration of P. koraiensis at both individual and population levels.

This study identified fruit species eaten by Leontopithecus chrysomelas (golden-headed lion tamarins; GHLTs) and related their consumption to seed dispersal. Two GHLT groups were monitored from September 2006 through August 2007 in Una Biological Reserve, Bahia, Brazil. GHLTs consumed fruit from 71 species, preferred mature fruit and swallowed the seeds of most species (76.8%). Smaller seeds were swallowed and larger seeds were generally discarded. GHLTs defecated in low quantities and more than 50% of the faeces contained seeds from only one species. Most faeces were deposited far from the parental tree (>20m) and only 24.2% under the parental tree. The defecation pattern of L. chrysomelas could reduce competition between seeds and facilitate the establishment of seedlings from the most consumed species. Faeces were deposited widely throughout home ranges and away from a seed's parental tree increasing the chances that seeds reach favourable environments and avoid competition with other seedlings. Additionally, defecations also occurred in the same habitat type as a seed's parental tree, keeping species within their typical habitat. GHLTs in Una Biological Reserve were efficient dispersers and might play an important role in the maintenance of floristic composition and regeneration of habitat.

The semi-arid Caatinga of the Brazilian northeast is a fragile, poorly known scrubland biome, which suffers increasing anthropogenic impacts. While 143 mammal species are known from the biome, few data are available on community composition or population parameters. In the present study, a 115-ha fragment of arboreal caatinga was surveyed in northern Sergipe in 2009 using standard line transect procedures. Total transect length was 133 km, and density estimates were calculated using sighting functions. Additional information on the occurrence of mammalian species was collected non-systematically. Nine species, including three carnivores, were confirmed in the study area, but only three were recorded in the surveys, two of which [the critically endangered blond titi, Callicebus barbarabrownae (Hershkovitz 1990), and the rock cavy, Kerodon rupestris (Wied-Neuwied 1820)] are endemic to the Caatinga. The third species was the common marmoset, Callithrix jacchus (Linnaeus 1758). C. jacchus and K. rupestris were relatively abundant, with estimated densities of 169.7 and 116.7 individuals per km 2 , respectively, but C. barbarabrownae was rare, and the local population was estimated to contain only five individuals, i.e., approximately four individuals per km 2 . If typical, densities this low would probably threaten the viability of C. barbarabrownae populations at most, if not all sites in which the species still occurs.

We determined the patterns of distribution and abundance of medium to large-sized mammals on an agricultural landscape in south-eastern Brazil. Here, we discuss some management recommendations to improve the conservation value of agricultural landscapes. From July 2003 to June 2004 we surveyed 284.4 km transects searching for tracks and visualizations of mammals in the main environments of an agricultural landscape in south-eastern Brazil. We recorded 25 native species, two exotic and six domestic species in the area: 23 species on native forest fragments, 19 on sugarcane plantations, 17 on eucalyptus plantations, and 12 on pasture areas. There were significant differences in species richness and frequency of occurrence among these environments. Pasture areas had the lowest species richness and sugarcane plantations the greatest frequency of occurrence. Some species are associated with open areas, whereas other species are associated with forested habitats. Although a considerable part of the original mammal diversity is still present, the community found is predominantly composed of species able to adapt to environmental alterations. Therefore, to improve the conservation value of agricultural landscapes in south-eastern Brazil, the maintenance of native forest fragments is essential, in addition to mitigation measures of the various agricultural impacts.

Galidictis grandidieri (Wozencraft 1986) is a nocturnal carnivoran endemic to the threatened spiny forest ecosystem of the Mahafaly Plateau in southern Madagascar. Previous investigations estimated a total population size of about 3000 individuals restricted to an area of 440 km 2 , making it one of the geographically most limited and rarest mammalian carnivoran species worldwide. Given the increasing threat through habitat destruction we compiled additional morphometric measurements and investigated the distribution and abundance of the species, using grid and transect captures. G. grandidieri were larger than indicated by previous samples and showed significant sexual dimorphism with a mean body mass of 1640 g for males and 1400 g for females (overall mean: 1500 g). The highest densities were found in the littoral forest at the western edge of the Mahafaly Plateau (six to eight individuals/km 2 ). From there, its abundance declined exponentially towards the east. The distribution of G. grandidieri is probably determined by decreasing water accessibility away from the cliff. We estimate a total distribution area of about 1500 km 2 and a total population size between 3115 and 4995 animals. Based on these estimates, G. grandidieri occurs in a much larger area than assumed so far, but reaches lower densities.

Predator control has frequently been applied in the management of private hunting areas in recent decades. This study analyzes capture records taken during predation control carried out in areas with hunting management, in a Mediterranean environment, in the northeast of the Iberian Peninsula between 1991 and 1999. Whether predator control complied with the law during this period is discussed, and the efficacy and selectivity of the methods are evaluated. Results reveal that predation control did not always comply with the law. They also indicate that the methods used were not selective, as they caught legally protected species during part of the study period. The results are examined with a view to establishing a rational management program for hunting areas and species conservation.

Lestodelphys halli and Thylamys pallidior are southernmost representatives of the Order Didelphimorphia. We analyzed their southern distribution compiling locality records south of 42°S (Chubut and Santa Cruz provinces). We found 87 locality records for L. halli and 105 for T. pallidior . The distribution of L. halli reaches the central plateaus of Santa Cruz province but avoids the northeastern corner of the Deseado Massif. We report the southernmost locality for this species. The eastern and southern distribution of T. pallidior follows the courses of major rivers and coastal areas and it was not found at altitudes >700 m. Its southern distribution is more reduced than in L. halli , not reaching latitudes south of 46°S. We have recorded 20 localities of sympatry between both taxa, all of them from owl pellet samples; however, we have not found conclusive evidence of syntopy by trapping at any site. Both marsupials have widespread distribution in south-central Patagonia with two different histories: one, that of L. halli , related to Patagonian steppes and the other one linked to arid and semiarid lowlands represented by T. pallidior .

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