A. Bocci, V. Aiello, S. Lovari, Excursion behaviour of female roe deer may depend on density, Behavioural Processes, Available online 5 April 2013, ISSN 0376-6357, 10.1016/j.beproc.2013.03.004.
The excursion behaviour of roe does was studied for two years in a low density population (ca. 6.5 ind./100ha), in an Apennine-continental forest of Southern Italy, through satellite radiotracking. During the rutting period, our radiotagged does (N=6) moved well outside their summer ranges, with an average exploration area eight times greater than summer ranges. The median duration of excursions was 51hours (range: 10-99hours). One female stayed away for a total of 11 days. In order further to understand this behaviour, we reviewed all studies (N=6) dealing with excursion behaviour of roe does and carried out in areas where population density was assessed through the same method (i.e. drive counts). Out of five ecological parameters included in the analysis, excursion behaviour of roe does females was found significantly and negatively associated only to population density: when density was low, the proportion of roaming does increased, probably because of the lower availability of “free” bucks during the short time of female oestrous.
André P. Silva, Luís M. Rosalino, Paul J. Johnson, David W. Macdonald, Neil Anderson, Kerry Kilshaw
Local-level determinants of wildcat occupancy in Northeast Scotland
European Journal of Wildlife Research, April 2013
We studied the influence of food abundance, land cover and disturbance on European wildcat (Felis silvestris silvestris Schreber, 1777) presence in Scotland. Wildcat records were collected using camera trapping, and prey data were assessed through linear transects and small mammal trapping. Surveys were carried out in three study areas in northeast Scotland. Wildcat occupancy was best predicted by a combination of food and land cover variables. This species detection was associated with higher rodent abundance and areas of higher habitat diversity encompassing patches of mixed and coniferous woodlands. Wildcat presence was negatively linked with the prevalence of dwarf shrub areas. We suggest that wildcat conservation actions at local scale should take into account the availability of feeding resources and landscape heterogeneity.
Randeep Singh, Aniruddha Majumder, Kalyanasundaram Sankar, Qamar Qureshi, Surendra Prakash Goyal, Parag Nigam
Interbirth interval and litter size of free-ranging Bengal tiger (Panthera tigris tigris) in dry tropical deciduous forests of India
European Journal of Wildlife Research; April 2013
We studied the interbirth interval (IBI) and litter size of the population of free-ranging Bengal tigers (Panthera tigris tigris) in dry tropical deciduous forests in Ranthambhore Tiger Reserve (RTR), Rajasthan, and Pench Tiger Reserve (PTR), Madhya Pradesh, between April 2005 and June 201Data on 15 breeding females in RTR and nine breeding females in PTR were collected using camera trapping, direct observation and radio-telemetry. The mean ± standard error of IBI (months) in RTR was 33.4 ± 3.7 and in PTR was 25.2 ± 1.8. A significant difference was observed between the mean IBI of tigresses in RTR and those in PTR (df = 9, P = 0.04). The estimated mean litter size in RTR was 2.3 ± 0.1 and that in PTR was 2.9 ± 0.2. There was a significant difference between the litter size in RTR and that in PTR (χ2 = 12.04, P = 0.017, df = 4). Since RTR and PTR are the important source populations of tigers in the Western and Central Indian landscapes, we propose that the tigers in these reserves be monitored, particularly for reproductive traits that are essential for understanding aspects of their population ecology.
Ad Vos, Tobias Nolden, Christiane Habla, Stefan Finke, Conrad M. Freuling, Jens Teifke, Thomas Müller
Raccoons (Procyon lotor) in Germany as potential reservoir species for Lyssaviruses
European Journal of Wildlife Research; April 2013
Raccoons can be found almost everywhere in Germany since their first successful introduction in 1934. Although the animal is a well-known reservoir species for rabies in the USA, during the last European fox rabies epizootic, only a few rabid raccoons were reported from Germany. In recent years, the raccoon population density has increased tremendously, especially in (semi) urban settings. Presently, Germany is free of terrestrial wildlife rabies. To assess the potential risk that the raccoon population in Germany could act as a reservoir species upon reemergence of rabies, the susceptibility of the local raccoon population was investigated. Wild-caught animals were inoculated with the most likely lyssavirus variants to infect the local population. It was shown that the raccoons were fully susceptible for a dog and raccoon rabies virus isolate. Also, five of six raccoons inoculated with a fox rabies virus isolate showed clinical signs. However, none of the raccoons infected with European Bat Lyssavirus type 1 succumbed to rabies; meanwhile, all these raccoons seroconverted. It is concluded that the highest risk for the raccoon population in Germany to become infected with lyssaviruses is through the importation of rabies infected dogs.
The Reliance of the Golden Jackal (Canis aureus) on Anthropogenic Foods in winter in Central Bulgaria
Evgeniy G. Raichev, Hiroshi Tsunoda, Chris Newman, Ryuichi Masuda, Dian M. Georgiev, and Yayoi Kaneko
Mammal Study 2013 38 (1), 19-27
Wild canid foraging behaviour and regional abundance are often affected by the availability of anthropogenic food, supplementing natural diet. The feeding habitats of the golden jackal (Canis aureus) were compared between two populations in central Bulgaria, for which food availability and the extent of anthropogenic-modified habitat differed. Stomach contents were collected from hunting bags during winters from 1997 to 2009 and compared between an agriculturalhilly region (Region 1) and a forested-mountainous region (Region 2). Although mammalian prey predominated in the jackal’s diet in the two regions, diets differed significantly between the regions: in Region 1 the main foods were domestic animals (30.2%), while in Region 2 wild ungulates proved to be the dominant food type (47.9%). We propose that although regional differences in jackal foraging habits were apparent between the two regions, foods originating from human activities were important in both regions. In Bulgaria, the golden jackal is regarded as a nuisance pest, requiring population control. Managing the availability of anthropogenic food sources to jackals, e.g., carcasses of wild and domestic animals, may implicitly reduce jackal abundance and/or discourage jackals from foraging around sites occupied by people.
Evaluation of Camera Trap Surveys for Estimation of Sika Deer Herd Composition
Takashi Ikeda, Hiroshi Takahashi, Tsuyoshi Yoshida, Hiromasa Igota, and Koichi Kaji
Mammal Study 2013 38 (1), 29-33
Camera trap method has been developed for monitoring wildlife, however, most studies using camera trap depend on baited camera sites to attract target wildlife. This is likely to bias estimates of population structure. We evaluated the use of non-baited camera trap for the estimation of herd composition of sika deer (Cervus nippon). Camera trap showed a distinct seasonal pattern in sex ratios (males/100 female), which remained lowest between May and October but increased in November. Sex ratios were influenced by the number of observed males, because the ratios were positively correlated with the number of males but not females. The number of males increased in autumn during rutting season. Fawns/100 female ratios showed a distinct seasonal pattern. Highest and lowest fawns/100 female ratios were obtained in November and May, respectively. The decrease of fawns/100 female ratios in May comparing with that in November may be because of the overwinter mortality of fawns. Camera trap method is superior in term of continuously conduct in long-term, collect reasonable seasonal patterns, automatically record large numbers of sample sizes and useful in all weather conditions.
R. Graham Reynolds, Alberto R. Puente-Rolón, Robert N. Reed, Liam J. Revell
Genetic analysis of a novel invasion of Puerto Rico by an exotic constricting snake
May 2013, Volume 15, Issue 5, pp 953-959
The tropical island Puerto Rico is potentially vulnerable to invasion by some species of exotic snakes; however, until now no established populations had been reported. Here we report and genetically characterize the nascent invasion of Puerto Rico by an exotic constricting snake of the family Boidae (Boa constrictor) using mtDNA and microsatellite data. Over 150 individual B. constrictor have been removed from Mayagüez municipality since May 2011, and our results from the genetic analysis of 32 individuals suggest that this population was recently founded by individuals of one subspecies from a genetic lineage common to zoo and breeding collections, but that the potential propagule pool consists of two subspecies. We also suggest that anthropogenic long-distance dispersal within the island of Puerto Rico may be occurring from the established population, with implications for further establishment across the island. This study represents the first report of the naturalization of an invasive species of boid snake in Puerto Rico and will be important in determining mitigation strategies for this invasion as well as providing a basis for comparison to other on-going studies of invasive snakes.
Helena Berglund, Johannes Järemo, Göran Bengtsson
Associations of invasive alien species and other threats to IUCN Red List species (Chordata: vertebrates)
May 2013, Volume 15, Issue 5, pp 1169-1180
Apart from acting synergistically or additively, threats to species may be associated or disassociated. Here we link global data on threatened Chordata species, mainly birds, mammals, and amphibians, with a probabilistic methodology to test whether the impact from invasive alien species co-occurs purely randomly, associated, or disassociated with impact from nine other major threats to biodiversity listed in the International Union for Conservation of Nature Red List database. Impacts from several of the other threats, in particular from natural disasters, are associated with the impact from invasive alien species. Three of the threats of anthropogenic origin, namely habitat loss, harvesting, and human disturbance, co-occur randomly with impact from invaders, and we suggest several explanations to this unexpected relationship, such as ambiguous evidence for associations between them and human-induced disturbances. Impact from invasive alien predators has a strong association with impact from native predators, indicating that similarity in autecology affects co-occurrences between threats. The threat from invasive predators is disassociated from intrinsic factors on islands, probably because species suffering from for instance inbreeding problems have low densities and rarely encounter invasive alien predators. The analysis of co-occurrence of impact from invasive alien species and other threats is a first step to understand and mitigate vulnerability of a community to the simultaneous exposure to invasive alien species and other threats. Association or disassociation between threats may depend on correlations between exposures and sensitivity to the threats or on the presence of one threat increasing or decreasing the sensitivity to another.
Aaron B. Shiels, Caitlin A. Flores, Arthur Khamsing, Paul D. Krushelnycky, Stephen M. Mosher, Donald R. Drake
Dietary niche differentiation among three species of invasive rodents (Rattus rattus, R. exulans, Mus musculus)
May 2013, Volume 15, Issue 5, pp 1037-1048
The diets of sympatric rodents partially define their realized niches. Identifying items in stomachs of introduced rodents helps determine rodents’ trophic positions and species most at risk of consumption. In the Hawaiian Islands, which lacked rodents prior to human arrival, three rodents (Rattus rattus or black rat, R. exulans or Pacific rat, Mus musculus or house mouse) commonly coexist in native habitats where they consume a wide range of plants and animals. These three rodent species were trapped in montane forest for 2.5 years; their stomach contents were analyzed to determine short-term diets (n = 12–95 indiv. per species), and isotopic fractions of δ15N and δ13C in their bone collagen were analyzed to further estimate their trophic positions (n = 11–20 indiv. per species). For all three species, >75 % of individuals had plants and >90 % had arthropods in their stomachs, and significant differences in mean relative abundances were found for food items in stomachs among all three rodents. Rodents may be dispersing some native and non-native seeds, including the highly invasive Clidemia hirta. Most identifiable arthropods in rodent stomachs were non-native, and no stomachs contained birds, snails, or lizards. The δ15N and δ13C signatures were consistent with trophic feeding differences revealed from stomach contents. Dietary niche differentiation by coexisting rodent species is evident in this forest, with Pacific rats being intermediate between the mostly carnivorous house mouse and the mostly herbivorous black rat; such findings can help forecast rodent impacts and direct management efforts in ecosystems where these invasive animals coexist.
Sozos Michaelides, Geoffrey M. While, Celia Bell, Tobias Uller
Human introductions create opportunities for intra-specific hybridization in an alien lizard
May 2013, Volume 15, Issue 5, pp 1101-1112
Introduction of individuals from multiple sources could create opportunities for hybridization between previously isolated lineages, which may impact on the invasion process. Identifying the phylogeographic origin of introduced populations is therefore an important task to further test the causes and consequences of human-mediated translocations. The common wall lizard (Podarcis muralis) shows a strong phylogeographic structure as a result of past isolation in glacial refugia, but it has also been commonly introduced outside of its native range. Here we analysed 655 base pairs (bp) of the cytochrome b sequence from 507 individuals from 23 introduced populations of P. muralis in England. We identified 12 unique haplotypes in the introduced populations that were nested into five native geographically distinct clades with genetic divergences ranging from 2.1 to 5.7 %. Multiple clade origin was common within populations, with a maximum of three different haplotype clades being represented within a single population. The genetic data are consistent with a scenario whereby initial establishment was a result of translocation of animals from their native range, whereas more recent establishment (i.e. since the mid-1980s) is the result of translocations of animals from previously established non-native populations. However, this requires further study. Overall, our results show that human introductions have created substantial opportunities for hybridization between genetically and phenotypically distinct lineages, which may have important consequences for the establishment success and long-term viability of introduced wall lizard populations.
Wouter F. D. van Dongen, Ilenia Lazzoni, Hans Winkler, Rodrigo A. Vásquez, Cristián F. Estades
Behavioural and genetic interactions between an endangered and a recently-arrived hummingbird
May 2013, Volume 15, Issue 5, pp 1155-1168
The invasion or expansion of non-native species into new geographic areas can pose a major threat to the conservation of biodiversity. These threats are augmented when the newly-arrived species interacts with native species that are already threatened by other ecological or anthropogenic processes. Potential interactions can include both competition for scarce resources and reproductive interference, including hybridisation. Understanding the dynamics of these interactions forms a crucial component of conservation management strategies. A recent contact zone occurs in the north of Chile between the endangered Chilean woodstar (Eulidia yarrellii) and the closely-related and recently-arrived Peruvian sheartail (Thaumastura cora), which expanded its range from Peru into Chile during the 1970s. We characterised the interactions between the species by combining population size estimates with molecular, morphological and behavioural data. We show that a low degree of hybridisation, but not introgression, is occurring between the two species. Despite interspecific morphological similarities, behavioural observations indicate that food niche overlap between the species is relatively low, and that the dietary breadth of sheartails is larger, which may have aided the species’ range expansion. Finally, woodstars dominate the sheartails in male–male territorial interactions. However, potentially increased energetic costs for woodstars associated with frequent territorial chases and courtship displaying with sheartails may exacerbate the effects of other threats on woodstar viability, such as human-induced habitat modification. This study highlights the value of implementing multidisciplinary approaches in conservation biology to gain a more complete understanding of interactions between recently-arrived and endangered species.
Zootaxa 3636 (4): 575–589 (8 Apr. 2013)
A new Stumpffia (Amphibia: Anura: Microhylidae) from the Ranomafana region, south-eastern Madagascar
SERGE H. NDRIANTSOA, JANA C. RIEMANN, MIGUEL VENCES, JOHANNES KLAGES, NOROMALALA R. RAMINOSOA, MARK-OLIVER RÖDEL & JULIAN GLOS
We describe a new species of small-sized frogs from degraded rainforest patches in the southern central east of
Madagascar. Stumpffia miery sp. nov. has a snout-vent length of 13–15 mm and can be distinguished from all other
nominal species of Stumpffia by its body size and absence of toe reduction combined with length reduction of fingers I, II and IV in external view. The advertisement call is a single tonal chirping note that ranges in duration between 51–88 ms and is emitted after relatively regular inter-note intervals (duration of 2679–4247 ms, call repetition rate 0.3/sec, frequency range 7700–8300 Hz, dominant frequency 7751–8225 Hz). Its type locality is the Ambolo forest fragment close to Ranomafana village in southeastern Madagascar. Molecular data from DNA sequences of one mitochondrial and one nuclear gene indicate a high divergence from all nominal species of Stumpffia, suggesting that it represents a strongly differentiated independent evolutionary unit. Stumpffia miery sp. nov. is apparently able to tolerate some degree of habitat degradation and therefore is probably not threatened with extinction.
Wetlands, April 2013
Tyler M. Harms, Stephen J. Dinsmore
Habitat Associations of Secretive Marsh Birds in Iowa
Drastic losses of wetland habitats across North America over the past century have resulted in population declines of many marsh birds therefore emphasizing the need for proper management of remaining wetlands for the conservation of marsh birds. Our objective was to evaluate the probability of site occupancy of secretive marsh birds in Iowa in response to habitat variables at multiple scales. We conducted call-broadcast surveys for eight species of marsh birds at wetlands in Iowa from 16 May–15 July 2009 and from 20 April–10 July 2010. We utilized occupancy models in Program MARK to estimate site occupancy probability based on habitat covariates for four species with the most detections (Pied-billed Grebe [Podilymbus podiceps], Least Bittern [Ixobrychus exilis], Virginia Rail [Rallus limicola], and Sora [Porzana carolina]). Wetland size had a positive effect on site occupancy for Least Bitterns, water depth positively affected site occupancy for Pied-billed Grebes and Least Bitterns, and percent cover of cattail positively affected site occupancy for Virginia Rails. Knowing habitat associations of secretive marsh birds in Iowa will allow us to provide guidance on wetland restoration and management decisions that will aid the conservation of these birds.
Ausband, David E., Mitchell, Michael S., Bassing, Sarah B., and White, Craig (2013)
No trespassing: using a biofence to manipulate wolf movements
Context: Conserving large carnivores can be challenging because of conflicts with human land use and competition with humans for resources. Predation on domestic stock can have negative economic impacts particularly for owners of small herds, and tools for minimising carnivore depredation of livestock are needed. Canids use scent marking to establish territories and avoid intraspecific conflict. Exploiting scent-marking behaviour may provide a means for manipulating canid movements.
Aims: We hypothesised that human-deployed scent marks (i.e. ‘biofence’) could be used to manipulate the movements of grey wolves (Canis lupus) in Idaho, USA.
Methods: We deployed 65 km of biofence within three wolf-pack territories during summer 2010 and 2011 and used location data from satellite-collared wolves and sign surveys to assess the effectiveness of biofencing.
Key results: Location data provided by satellite-collared wolves and sign surveys in 2010 showed little to no trespass of the biofence, even though the excluded areas were used by the packs in previous summers. We also opportunistically deployed a biofence in between a rendezvous site of a resident pack and a nearby sheep grazing allotment; the pack was not implicated in any depredations in summer 2010, even though they had killed sheep every year since 2006. Location data provided by satellite-collared wolves in summer 2011 showed that wolves did trespass biofences.
Conclusions: Biofencing effectively manipulated the movements of wolves in the first year of our study, but not the second.
Implications: Our work suggests that biofencing may be most limited by the apparent necessity to maintain a continuous presence once the biofence is established. The inherent labour and costs associated with such efforts may limit the usefulness of biofencing. Our work can be improved on through further testing that maintains biofencing over a longer timeframe (>3 months), samples several animals per treatment pack, and uses a treatment and control design.
Bleach, I., Beckmann, C., Brown, G. P. and Shine, R. (2013), Effects of an invasive species on refuge-site selection by native fauna: The impact of cane toads on native frogs in the Australian tropics. Austral Ecology. doi: 10.1111/aec.12044
Invasive species can induce shifts in habitat use by native taxa: either by modifying habitat availability, or by repelling or attracting native species to the vicinity of the invader. The ongoing invasion of cane toads (Rhinella marina) through tropical Australia might affect native frogs by affecting refuge-site availability, because both frogs and toads frequently shelter by day in burrows. Our laboratory and field studies in the wet-dry tropics show that native frogs of at least three species (Litoria tornieri, Litoria nasuta and Litoria dahlii) preferentially aggregate with conspecifics, and with (some) other species of native frogs. However, the frogs rarely aggregated with cane toads either in outdoor arenas or in standardized experimental burrows that we monitored in the field. The native frogs that we tested either avoided burrows containing cane toads (or cane toad scent) or else ignored the stimulus (i.e. treated such a burrow in the same way as they did an empty burrow). Native frogs selected a highly non-random suite of burrows as diurnal retreat sites, whereas cane toads were less selective. Hence, even in the absence of toads, frogs do not use many of the burrows that are suitable for toads. The invasion of cane toads through tropical Australia is unlikely to have had a major impact on retreat-site availability for native frogs.