Volume 78, Issue 1

A review of population and community dynamics and habitat selection of rodents in complex desert landscapes is presented. Population dynamics of rodents in all deserts are driven mainly by resource pulses induced by rainfall events. In a long-term perspective, this pattern is sometimes interrupted by rare extreme weather events and by habitat transformation due to wildfire or climate change. Rainfall-population density relations were found to be modified by intrinsic (population autoregulation, habitat selection) and extrinsic (interspecific competition, predation) processes, but the relative importance and geographic specificity of these processes are unclear. Density-dependent habitat selection was found in all studied desert rodent species inhabiting more than one habitat. Density-dependent habitat selection was expressed in different types of population regulation, resulting in density-dependent or density-independent habitat distribution. However, processes of density-dependent habitat selection have been studied in only one region; there are no data yet to analyze how different strategies of habitat selection vary among different desert regions. Dynamics of community composition include one widely distributed pattern, an increase in species richness with density. Another pattern, zero-sum community dynamic, was found in North American deserts. Dynamics of the niche community structure is expressed in the increase of niche overlap with density growth. In Palaearctic deserts, this increase in niche overlap was accompanied by stronger aggregation of niches in spatial guilds. The last phenomenon was not recorded in North American deserts, which reflects differences in expression of spatial guilds between Palaearctic and Nearctic rodent communities.

Cryptotis parva exhibits a geographic range and ecological requirements unique among North American soricines: it possesses a latitudinal distribution, metabolism and communal nesting pattern more like the crocidurines of the eastern hemisphere. We utilized oxygen consumption (VO 2 ) techniques to examine metabolic shifts and video to document activity patterns and dynamics of solitary and group nesting C. parva . Between ambient temperatures of 4°C and 34°C, solitary C. parva demonstrated an inverse relationship between ambient temperature (T a ) and resting metabolic rate (RMR); thermal neutral zone (TNZ) was very narrow, between a T a of 34°C and 36°C. VO 2 was measured in groups ranging in size from one to eight at T a s of 4°C, 14°C, 24°C and 34°C. The group size had a significant effect on the median RMR and median predicted Kleiber value and was more effective at reducing metabolic cost at a lower T a . In a second experiment designed to assess the effects of huddling group size and incubator T a on the T a of the nest chamber, both had significant effects. Group size had significant effects on the T a of the nest chamber at incubator temperatures of 5°C, 10°C, 15°C and 32°C, but not at 25°C. We found no behavioral or physiologic evidence of heterothermy.

Under the hypothesis that the reproductive activity of a rodent species is influenced by conditions of the environment and by coexistent rodents, we assessed the relationship between environmental variables and reproductive activity of rodents at two spatial scales, field borders and trap sites, during the breeding period (spring, summer and autumn seasons) in pampean agroecosystems of Argentina. We distinguished between active and inactive sites, based on female reproductive condition. We conducted several statistical analyses to compare between active/inactive borders and trap sites for vegetation-rodent and rodent-rodent associations. The environmental variables useful for distinguishing active sites from inactive ones were different for each rodent species. Whereas vegetation cover, at the two habitat scales analyzed, seemed to be important for Akodon azarae , the crop types adjacent to borders seemed to be significant for Calomys musculinus to differentiate active/inactive sites. In the case of Calomys venustus , we could not identify one variable that reflected differences between border types. These associations would be related to the use that each rodent species makes of border and cropfield habitats, together with the resources they need at each moment of the breeding period.

The purpose of our study was to characterize the diet of the common genet Genetta genetta in the Djurdjura Mts., north of Algeria. Through a year-round survey, we collected 360 feces and identified 1970 items. Arthropods (33%) and mammals (25%) were dominant, followed by wild birds and plants. The wood mouse Apodemus sylvaticus (65% within mammals) and Coleoptera (66% within arthropods) were dominant throughout the seasons. We observed striking seasonal variations in the common genet’s diet, with arthropods peaking in summer, mammals and wild birds dominating in winter, and energetic plants more consumed in autumn. Our study underlined the opportunistic feeding habits of the common genet with high values of trophic indices throughout the seasons, and the species’ capacity to adjust its food spectrum on seasonal resource availability. Our results confirmed that the common genet has an intermediate diet between generalist and specialist, feeding on a wide spectrum of items but relying on the wood mouse as the main energetic source. The diet of the species in Djurdjura Mts. included a great proportion of arthropods, thus, reflecting the “Mediterraneity” of the feeding spectrum of the common genet in northern Algeria.

The short-tailed weasel ( Mustela erminea ) is a Holarctic boreo-montane species that has one of the largest natural geographic ranges of any mammal. At its southern range limits in arid western North America, the species is rare, and factors associated with its distribution are poorly understood. We hypothesized that the availability of voles ( Microtus ) as prey was a key limiting factor for the distribution of the species. Consequently, we predicted that important variables associated with the occurrence of short-tailed weasels included snow cover and riparian habitat, both of which are linked to abundant vole populations in this region. We tested these predictions in New Mexico using ecological niche models developed with a maximum entropy algorithm (MaxEnt) and based on bioclimatic and biophysical variables. Consistent with our predictions, distribution of the short-tailed weasel was primarily determined by high winter snowfall and proximity to perennial streams. Descriptive habitat data associated with specimen records supported a close association of short-tailed weasels with riparian zones, especially those characterized by the presence of sedges and ponds made by the American beaver ( Castor canadensis ). We conclude that the short-tailed weasel is facing conservation threats in this region due to a fragmented distribution, degradation of riparian habitats, altered small mammal prey communities, and climate change. We recommend that the short-tailed weasel be considered in conservation planning in this region and that management focus on means to enhance riparian habitat and curtailing dangers posed by climate warming.

The wildcat is a protected species in Europe but the lack of information on its status in many areas of its distribution range is an obstacle to conservation initiatives. To assess the status of the species over a 54,300 ha Mediterranean protected area in southwestern Spain (Doñana National Park, DNP), we carried out track censuses during the wet season of 2007–2008 and 2008–2009 in 2×2 km 2 quadrants and set camera traps from June 2008 to October 2010 in quadrants or nearby quadrants where cat tracks were detected. We detected a total of 52 cat tracks for both study years and identified six different individuals from 28 photographs taken at 12 out of 166 trapping stations. We hypothesized that the causes of the a priori surprising low abundance of the species in the area might be multifold and might be explained by the historic competitive exclusion of the species by the Iberian lynx, the decrease of rabbit population in the DNP during the past decades, the isolation of DNP from the nearest natural areas that could have slowed the recovery of wildcat populations after a species declining and a potential increased mortality rate over time due to disease transmission from domestic cats.

Introduced populations of species pose one of the greatest threats to the persistence of native species. Documentation of distribution, range expansion and habitat use of introduced populations are key components of developing effective management strategies for the control and eradication of invasive species. In 2006 and 2007, we surveyed four islands in Biscayne National Park for nests to evaluate the presence of red-bellied squirrels ( Sciurus aureogaster ) and the distribution and index of dispersion of their nests in the Florida Keys archipelago within the Atlantic Ocean. Red-bellied squirrels were initially introduced to Elliott Key, Florida, USA in in 1938. We documented evidence of squirrels on two additional islands, Sands Key and Old Rhodes Key, which adds to concerns of spread of this introduced squirrel to areas with endangered endemic insular mammals. Squirrel nests were documented only in mixed-hardwood forest, and nests had a clumped distribution within this forest type. Range expansion was a chief concern to the National Park Service, as continued spread could result in squirrels exiting the park, and prompted management action. Understanding nest site selection and distribution was critical for developing an eradication strategy for the introduced population of red-bellied squirrels from south Florida.

Studies of animal ranging patterns and the influencing ecological factors are useful for understanding the relationship between aspects of animal behavior and ecology. In a year-long study, we investigated the ranging behavior and other determining factors for a group of François’ langur in an isolated habitat of approximately 25.7 ha in Fusui Reserve, China. The François’ langur home range was estimated to be 15.3 ha, covering ∼60% of their total habitat. The mean yearly day range length estimate was 802.5 m (SD=295.5 m). Langurs changed sleeping sites approximately every 3 days, resulting in increases in the amount of grid cells used and the range length. Food availability of flowers and fruits were seasonal, whereas both mature and immature leaves of most trees were perennial. Ranging behavior was not significantly correlated with the availability of mature leaves, immature leaves, buds, fruits (ripe and unripe fruits) or seeds (p>0.05). These results suggested that variations in food type availability were not factors influencing ranging behavior for this langur group, whereas sleeping site changes, and probably predation avoidance, are factors that influence the ranging patterns of the langur group.

Small human-used root cellars are the most widespread bat hibernacula in Latvia, but their importance was hitherto underestimated. We compared bat species diversity and numbers of individuals in root cellars with that in other types of bat hibernacula in Latvia over 35 years. Both species diversity and number of bats hibernating in root cellars were significantly lower than that in other roost types. However, two species, Plecotus auritus and Eptesicus nilssonii , extensively used root cellars as hibernacula. The maximum population size of bat species hibernating in root cellars in Latvia was estimated to be from 27,600 to 42,450 individuals for P. auritus and from 7940 to 12,210 for E. nilssonii . We conclude that root cellars are crucial hibernation sites for P. auritus and E. nilssonii in Latvia.

In studies on frugivory and seed dispersal, it is frequently assumed that individual frugivores of the same population behave as equivalents. However, there is growing evidence from dietary studies pointing out that, in many natural populations, individuals use different subsets of the total resource pool. As heterogeneity in foraging behavior and food selection may affect the outcome of the seed dispersal process, we tested whether yellow-shouldered bats Sturnira lilium (E. Geoffroy St.-Hilaire, 1810), the key neotropical seed dispersers, show interindividual variations in fruit preferences. Thirty individuals were submitted to cafeteria trials in a flight tent, when they were offered fruits of Solanum variabile Mart. (Solanaceae) Cecropia pachystachya Trec. (Urticaceae), and Piper aduncum L. (Piperaceae), which belong to the favorite genera consumed by S. lilium . Although S. variabile had the highest consumption rates on average, there were variations among individuals in the fruits consumed in the second and third places. These findings, together with interindividual differences in foraging areas observed in the same population, may be interpreted as preliminary evidence of individual specialization. As a possible consequence, frugivorous bats of the same population, despite being all legitimate dispersers, may differ in their efficiency.

The European hedgehog is strictly protected in the Republic of Ireland but has been little studied. Carcasses, such as road kill casualties, can provide valuable information on population demographics, parasite load and general body condition. This study aimed to examine the species of endoparasites present in hedgehogs, their prevalence and intensities and whether differences occurred depending on the age and sex of the hedgehog. Carcasses were collected and examined from around Ireland, over a 3-year period. In 21 of the 23 hedgehogs examined, endoparasites were identified. The nematode species, Crenosoma triatum and Capillaria erinacei were both positively identified. C. striatium was confined to the lungs, whereas C. erinacei was the most prevalent (87%) endoparasite and occurred in the stomach and intestines. There was a significantly higher load of Crenosoma striatum observed in male hedgehogs compared to females, but no significant difference was observed in the intensity of C. erinacei between the sexes. In all tissues, a greater mean endoparasite load was observed in male hedgehogs. Sex differences in exposure or immunity to parasitism could be related to the males’ larger home range and the effects of oestrogen levels on immunity.

Body size determines many physiological and ecological variables; however, there are few studies on this parameter for the Antillean manatee ( Trichechus manatus manatus ). We studied an osteological collection and databases of Antillean manatees in Mexico to infer body measurements and to determine the body mass (BM)/body length (BL) relationship. The studied sample included 165 specimens: skulls (n=60), necropsies (n=51), and individuals captured for health assessment purposes (n=54). Specific regression equations for estimating BM were derived using the following craniometrical parameters: condylobasal length (BSL), occipital condyle width (OCW), and foramen magnum width (FMW). OCW and FMW were not significantly correlated with BL. The equation of the fitted model was BL=-121.644+10.8861×BSL (p<0.05, r 2 =0.93, SE=14.72). The allometric equation of weight/length relationship was defined as BM=exp (2.7477+0.0110957×BL) (p<0.05, r 2 =0.99, SE=0.07). The model showed a significant relationship between BL and BSL (>95%). Regression equations proved to be useful in estimating BL when only highly decomposed carcasses or skull dry bones are available, and in estimating weight when it is impossible to do it directly. Studies on biology history and age determination in T. m. manatus are required in order to establish an adequate age classification.

We determined the diet of the poorly-studied Middle Eastern wolves ( Canis lupus ) in central Iran in 2009–2010. Food items consisted mainly of farmed chicken and domestic goat (i.e., anthropogenic resources) using both qualification and quantification methods. In contrast, we identified the remains of wild ungulates in negligible quantities. Our data simulations showed that poultry and goats are both primary food items of wolves in the study area. The relative importance of main prey items did not vary seasonally, and, although there were some minor differences in secondary food items, we did not reveal any seasonal effect in diet composition. The negligible consumption of wild prey strongly suggests that wolves are not, at present, a limiting factor for wild prey in our study area. Appropriate management of illegal dumping, in conjunction with excluding wolves and other carnivores from human refuse, would minimize the chance of human-carnivore encounters, wolf-livestock conflicts and, in turn, the persecution of carnivores. Our study contributed to our knowledge of the feeding ecology of the Middle Eastern wolves in areas with a relatively high abundance of anthropogenic foods and a moderately low abundance of wild prey.

Myotis ruber is a widely distributed bat in South America, but it is considered rare and its natural history is virtually unknown. These factors contribute to the classification of the species as vulnerable regionally and nearthreatened globally. In this context, the aim of this note is to present new data about the reproductive biology of M. ruber , thus expanding the knowledge about its natural history and, consequently, contributing to the conservation of the species. After an extensive effort to capture bats in southern Brazil, we captured 40 individuals of M. ruber . Pregnant females (n=17) were observed mainly in October in different years. In addition, seven immature individuals were captured. Based on our results, it is expected that the species will fit the general pattern for bats determined by climate and food resources, but our data do not allow us to assign conclusive reproductive patterns. Although not conclusive, the information presented in this note represents the first opportunity to gather breeding information about this rare and threatened species.

This note reports the first record of Micronycteris sanborni in Amazonas State, Brazil. It extends the species’ known range >2000 km northwestward and represents the first record of M. sanborni in a humid tropical ecosystem, suggesting that the species might not be exclusive to dry areas, as previously thought. The individual was captured in Vismia -dominated secondary forest within the fragmented landscape of the Biological Dynamics of Forest Fragments Project. We present morphometric data and provide the first description of the echolocation calls of this poorly known species.

Scotophilus kuhlii Leach, 1821 has only been reported from Chaklala and Chakri in Punjab, Pakistan. We captured five specimens from Lahore in a 2-year survey from June 2009 to May 2011. This is the first report of this species from Punjab province and the first from Lahore (31°29.223 N, 074°24.632 E) since the 1920s. The external body, cranial and bacular measurements of the captured specimens were compared with the available literature. The forearm length (n=5) was 49.40±3.03 mm, the greatest length of the skull (n=4) was 18.98±0.61 mm and C-M 3 (n=4) was 6.27±0.49 mm. The echolocation call parameters of 25 pulses from five calls of the species were also analyzed. The mean frequency of maximum energy was 56.9±3.6 kHz, the mean start and end call frequencies were 103.5±12.3 kHz and 50.6±1.0 kHz, respectively.