Mean Group Size Research Articles

The forgotten Grevy's zebra Equus grevyi population along the Kasigau Corridor ranches, SE Kenya: recent records and conservation issues

AbstractSince the 1970s, the globally endangered Grevy's zebra Equus grevyi has suffered a substantial reduction in range and population size. Grevy's zebra was introduced into the Tsavo ecosystem in two translocations: 22 individuals released in Tsavo East National Park in 1964 and 30 individuals released in Tsavo West National Park in 1977. This study focuses on the Tsavo East subpopulation within the Kasigau Corridor REDD+ Project Area. Data were collected from 2011 to 2014 using systematic and ad lib methods, while vegetation stratification was based on tonnes of CO2e per hectare. Cumulatively, 785 Grevy's zebra were seen in 210 encounters. The largest single group comprised of 24 individuals; mean group size was 4 ± 3. Foals comprised 10% of all individuals seen and were recorded across most months, suggesting year‐round breeding. The range core for the Grevy's zebra in this area was estimated to be 400 km2. Its density was estimated at 0.09 ± 0.038 individuals per km2, translating to a population of 36 ± 15 individuals (range: 6–67) based on the estimated core range. Grasslands and sparse Acacia–Commiphora vegetation strata were used significantly more than expected. Despite constituting only about 2–3% of the global Grevy's zebra population, this subpopulation could still play a role as a – disconnected – reserve population.

Understanding repeatability and plasticity in multiple dimensions of the sociability of wild female kangaroos

Sociability, how individuals interact with conspecifics, is considered to be a key axis of animal personality. Consistent differences between individuals in measures of sociability have been demonstrated in some taxa, yet individuals also exhibit plasticity in their sociability across differing ecological conditions, particularly in gregarious species that do not occur in stable cohesive groups. Although repeatability and plasticity of measures of sociability are both important for understanding animal personality they have rarely been studied concurrently. Between and even within species, multiple behaviours have been considered to represent sociability, but there is still little understanding of the degree to which different measures of sociability reflect distinct traits. In this study, our first aim was to determine the repeatability of four different measures, representing two broad aspects of individual females' sociability, in a wild population of eastern grey kangaroos, Macropus giganteus. Our second aim was to investigate how shorter-term environmental conditions and individuals' states related to plasticity in these measures. Using data collected each month over a 5-year period on over 100 adult females, we analysed factors contributing to variation in individuals' grouping patterns (to reflect general gregariousness) and in the number of different conspecifics with which individuals associated (their ‘choosiness’ of social partners). Rainfall, body condition and reproductive state were all related to females' mean group sizes, and females with older dependent young foraged further from their neighbours. Females were more selective about group members when there was more food, and when they were in poor or excellent body condition. Although social preferences exist among females in this population, and females' measures of sociability are repeatable and differ between individuals over the long term, these current findings suggest that the influences of individuals' states and environmental conditions contribute to variation in females' patterns of sociability over shorter periods.

Size and structure of the southernmost population of the Endangered Barbary macaque Macaca sylvanus in the western Moroccan High Atlas

AbstractThe Barbary macaque Macaca sylvanus is imperiled throughout its distribution range in north-west Africa. In the summers of 2009 and 2013 we used the piecewise line-transect distance sampling method to study the southernmost population in the High Ourika valley, in the western High Atlas of Morocco. This rugged mountainous area is dominated by degraded fruit-poor environments, mostly holm oak Quercus rotundifolia forest patches. We located four and two groups in 2009 and 2013, respectively, and estimated population sizes of 122 and 84 individuals. The mean group size was 12 individuals in 2009 and 46 in 2013. The estimated mean density (individuals per km2) varied among groups (10–171), with a mean of 27. The population structure varied significantly among groups and years. Our records comprised 24.8 and 20% adult males, 24.8 and 22% adult females, 11 and 13% subadults, 13 and 17% juveniles and 26.4 and 26.3% infants in 2009 and 2013, respectively. In both years 50–56% of the population consisted of young individuals (subadults excluded). The mean sex ratio among adults was 1 : 1. The apparent fecundity rate was 1.06 infants per adult female. We propose conservation actions to protect this peripheral population of Barbary macaques.

Species separation in artiodactyl communities by the criterion of territorialism: The hypothesis of olfactory exclusion

The interspecies distinctions were determined in two artiodactyl communities from geographically distant populations by means of discriminant analysis of four traits: altitude, mean body mass, mean group size, and territorialism. These communities inhabit similar landscapes of the Altai and Himalayas. They are formed by species with different territorial systems (year-round and seasonal), and also by species without such systems. By this attribute, the species ratio was 1 : 1 : 2 in the community of Altai and 1 : 3 : 3 in the Himalayan community. Territorial system diversity is a natural character of the communities under study; it provides the basis for essential distinctions in the structure of specific biological signal fields. An inhibiting role of year-round territorialism in population separation was demonstrated. In it, species are characterized by a seasonal pattern of scent marking by dermal gland secretion. Based on the results, a principle was formulated for the separation of species with active biological signal fields in Cetartiodactyla communities. According to this principle, two species with year-round territorialism, the basic element of which is intensive scent marking, cannot occupy the same habitat. The mechanism of olfactory exclusion of mammalian species with specific functioning of the olfactory system is discussed.

Estimation of Species Area Abundance from Point Abundance Data, Using Effective Detection Areas from Camera Traps

Estimations of species abundance are a common goal of wildlife monitoring surveys, but debate remains as to which methods are theoretically and practically most useful. Abundance-induced heterogeneity (AIH) models developed in the early 2000s allowed estimation of point abundance from repeated presence-absence data (e.g. occupancy models), and advanced estimation of point abundances of unmarked species. AIH models, however, do not provide an estimate of the effective detection area sampled. Therefore the absolute number of individuals in a survey area cannot be estimated directly. Recently, methods have become available to determine the effective detection area sampled by camera traps. Our objective was to present a novel method to estimate the absolute number of individuals of a species in an area from point abundance data using effective detection areas from camera traps. This would make AIH models available for population estimates. We applied this newly developed Species Area Abundance (SAA) model to a 3-month camera trapping data set of Bawean warty pigs (Sus blouchi) from Indonesia, and compared the result to an independent Random Encounter Model (REM) estimate from the same data. Population sizes and uncertainties estimated by the SAA and the REM model were comparable. Differences in density estimations between the REM and SAA model were not significant when mean group size was included in the REM. The less restrictive assumptions regarding camera trap placement of the SAA model compared to the REM might make it more practical to study cryptic and unmarked animal populations. Further studies are needed to determine the accuracy and practicality of the SAA model using a range of differrent sampling designs and focus species.

鄱阳湖4种鹤类集群特征与成幼组成的时空变化

PDF HTML阅读 XML下载 导出引用 引用提醒 鄱阳湖4种鹤类集群特征与成幼组成的时空变化 DOI: 10.5846/stxb201508191733 作者: 作者单位: 江西师范大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金资助项目（31260517） Temporal and spatial variations in the group characteristics and adult-juvenile composition of four crane species in Poyang Lake, China Author: Affiliation: Jiangxi Normal University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:2014年10月-2015年4月，采用样点法对鄱阳湖45个样点的白鹤（Grus leucogeranus）、白头鹤（G. monacha）、白枕鹤（G. vipio）和灰鹤（G. grus）的集群大小、集群类型和成幼组成进行调查。结果显示，白鹤的平均集群大小（23.86±10.26）只（集群数N=104），白头鹤（6.42±1.63）只（N=98），白枕鹤（6.09±2.55）只（N=105），灰鹤（5.55±1.26）只（N=246）。仅白头鹤中期集群大小显著小于后期，其余鹤类各时期及灰鹤各地区的集群大小差异不显著。鄱阳湖鹤类的集群大小并不符合警戒行为对集群大小的预测，生境质量差异可能是影响鄱阳湖鹤类集群大小的主要原因之一。4种鹤类均在1-5只个体的小集群中出现频度最高。白鹤在>35只个体集群中的个体比例最高，而白头鹤、白枕鹤和灰鹤在1-5只个体集群和>35只个体集群均有较高的个体比例。白鹤、白头鹤、白枕鹤和灰鹤均以家庭群为主，其家庭群所占比例分别为（64.29%，总集群数N=98）、（71.91%，N=89）、（70.77%，N=65）和（63.11%，N=206）。鄱阳湖鹤类以家庭群为主表明，保证充足的食物供应可能比花费更多的觅食时间更为重要。白鹤家庭群以2成1幼为主（65.08%），白头鹤（51.56%）、白枕鹤（52.17%）和灰鹤（47.69%）以2成为主。白鹤、白头鹤、白枕鹤和灰鹤群体的幼鸟比例分别为12.27%（个体数N=1695）、14.42%（N=416）、16.59%（N=229）和20.46%（N=655）。2成2幼集群比例极低表明，白鹤家庭同时抚养2个幼鸟成活的难度较其它3种鹤类大。4种鹤类在各时期的幼鸟比例差异不显著。在灰鹤个体数较多的3个地区中，都昌候鸟省级自然保护区（25.25%）和东鄱阳湖国家级湿地公园（25.14%）的幼鸟比例分别显著和极显著地高于鄱阳湖国家级自然保护区（14.24%）。鄱阳湖白鹤的幼鸟比例多年来均处于较低水平，白头鹤的幼鸟比例较2012-2013年冬季明显下降，灰鹤和白枕鹤种群可能处于稳定或增长状态。 Abstract:Poyang Lake is the largest freshwater lake in China, and many waterbirds, including four endangered crane species, overwinter at this lake each year. Feeding and resting are the behaviors primarily exhibited by the wintering waterbirds, that Poyang Lake provides good food and rest resources for them. However, no comprehensive data about the wintering ecology of these crane species exists. From October 2014 to April 2015, we investigated the group sizes and adult-juvenile compositions of the Siberian crane (Grus leucogeranus), hooded crane (G. monacha), white-naped crane (G. vipio), and common crane (G. grus) at 45 survey sites on Poyang Lake using the point count method. The results showed that the mean group sizes of the four crane species were (23.86±10.26) for the Siberian crane (group number N=104), (6.09±2.55) for the hooded crane (N=98), (6.09±2.55) for the white-naped crane (N=105), and (5.55±1.26) for the common crane (N=246). Crane group size in Poyang Lake did not conform to predictions based on their vigilance behavior. However, habitat quality may explain this discrepancy. The group size of hooded cranes at the mid-winter stage was significantly smaller than during the late winter stage, whereas other cranes showed no significant differences between the three wintering stages. The common crane group size also showed no significant differences between regions. The four species of cranes most frequently appeared in groups of 1-5 individuals. Most Siberian crane individuals appeared in groups of 35 individuals or more, whereas other cranes were in groups of 1-5, or more than 35 individuals. The Siberian crane (64.29%, total group number N=98), hooded crane (71.91%, N=89), white-naped crane (70.77%, N=65), and common crane (63.11%, N=206) appeared mainly in family groups, suggesting that ensuring an adequate supply of food was more important than increasing foraging time. The highest percentage of Siberian crane family group types was two adults with one offspring (65.08%), whilst two adults predominated in the hooded crane (51.56%), white-naped crane (52.17%), and common crane (47.69%) populations. The lower percentage of family types with two adults and two offspring indicated that Siberian crane families found it more difficult than the families of the other three cranes to raise two offspring at the same time. The percentage of juvenile Siberian cranes was 12.27% (individual number N=1695), 14.42% (N=416) for the hooded crane, 16.59% (N=229) for the white-naped crane, and 20.46% (N=655) for the common crane. There was no significant difference in the percentage of juveniles over the three wintering stages for any of the crane species. Duchang Provincial Migratory Birds Nature Reserve and East Poyang Lake National Wetland Park were found to contain significantly and extremely significantly (χ2=6.495, P=0.011 and χ2=9.012, P=0.003, respectively) more common cranes (25.25% and 25.14%, respectively) than Poyang Lake National Nature Reserve (14.24%). The percentage of juvenile Siberian cranes remained low in Poyang Lake, whereas that of the hooded cranes significantly decreased between 2014 and 2015 from the corresponding percentage of the population in 2012-13. The population of common cranes and white-naped cranes remained stable or increased, which suggested that Poyang Lake is able to maintain and develop healthy populations of these cranes. 参考文献 相似文献 引证文献

Habitat use by grey-crowned babbler, Pomatostomus temporalis, in urban and peri-urban environments

Habitat loss in the urban environment leads to a high rate of local extinction of native fauna. In contrast, where key habitat structures, such as woody debris, shrubs and trees, are maintained, urban landscapes can retain many native species. To manage urban habitats successfully for urban bird communities, it is, therefore, necessary to understand the habitat requirements of the species using them. We have previously shown that the grey-crowned babbler, Pomatostomus temporalis, exhibits similar mean weight, sex ratio and group size in natural and altered habitat in and around Dubbo, New South Wales. In the present study, we detail the movements and habitat use of the groups that inhabit urban areas. We found that groups behaved similarly in urban and peri-urban areas, but showed small differences in the frequency of behaviours, based on the habitat feature that was available. The results suggested that, despite the decline of the grey-crowned babbler in the southern parts of its range, this species is able to survive in altered habitats, if nesting habitat and ground cover remain available and neighbouring groups persist nearby. Because other woodland bird species have shown similar responses to urban environments, managers of urban parkland should provide foraging substrates for a variety of woodland bird species, including vulnerable species, to ameliorate threatening processes and protect key habitat requirements.

How rare is rare? Quantifying and assessing the rarity of the bush dog Speothos venaticus across the Amazon and other biomes

AbstractThe bush dog Speothos venaticus is a medium-sized Neotropical canid. It is considered to be rare and its biology and population parameters are still poorly understood. The Amazon is one of the main strongholds of this species and is important for maintaining viable populations, as the region still holds extensive tracts of pristine habitat. We gathered field data from camera-trap studies throughout the Brazilian Amazon to estimate the relative abundance of the species and gain an understanding of its rarity, and how this compares with estimates from other vegetative formations and for sympatric hypercarnivores. We focused on three pristine or partially disturbed sites and one fragmented site. The estimated relative abundance of the species was 0.060–0.185 individuals per 100 trap-days, confirming that the species is rare. The bush dog's abundance in the Amazon is equivalent to that in all other areas outside the Basin. The mean group size recorded was c. 2.5 individuals. There were no differences in group sizes between forests in the Amazon and in other regions of Central America; however, there were significant differences between forests and open habitats. A combination of competition/predation, habitat structure/integrity, and disease may be acting synergistically in determining the abundance and rarity of bush dogs.

Morphological evolution of the mammalian cecum and cecal appendix

The evolutionary pressures leading to the appearance of the cecal appendix, its evolutionary relationships with the cecum, and the link between these gastrointestinal characters and ecology remain controversial. We collected data on appendix presence and size, other gastrointestinal characters, ecological variables, dietary habits, and social characters hypothesized to drive appendix evolution for 533 mammalian species. Using phylogeny-informed analyses, we identified the first evidence of a positive correlation between appendix presence and cecal apex thickness, and a correlation with cecal morphology, suggesting that the appendix and cecum may be evolving as a module, the cecoappendicular complex. A correlation between appendix presence and concentration of cecal lymphoid tissue supports the hypothesis of an adaptive immune function for this complex. Other new findings include an inverse correlation between relative cecum length and habitat breadth, and positive relationships between cecum length and mean group size, and between colon length and weaning age.

Harbour porpoise (Phocoena phocoena) presence, abundance and distribution over the Dogger Bank, North Sea, in winter

An area in the central North Sea was surveyed in November 2011 in order to estimate the abundance and density of harbour porpoises (Phocoena phocoena). A total of 2833 km of pre-determined trackline were acoustically surveyed, of which 28% included visual effort. The poor sighting conditions during the survey limited visual effort and demonstrated the advantage of using acoustic techniques for studying harbour porpoise in winter months. Absolute abundance and density estimates were calculated from acoustic encounter rates using estimates of probability of detection and mean group size. The density of harbour porpoises in the west of the survey area was almost double that in the east, with UK waters to the south-west of the Dogger Bank having the highest density of the area surveyed. The overall acoustic encounter rate was higher than most other surveys in the North Sea. The mean density across the survey area of 0.63 (95% CI 0.27–1.52) individuals km−2and distribution of porpoises was similar to that documented in the summer suggesting that high abundance of harbour porpoises in the west of the North Sea is not confined to summer months. This information is particularly relevant given plans for the construction of a large offshore wind farm on the UK section of the Dogger Bank; the resulting impacts, including acoustic disturbance from pile driving, will potentially affect substantial numbers of harbour porpoises.

Status, abundance and population ecology of Nilgai (Boselaphus tragocamelus Pallas) in Aligarh District, Uttar Pradesh, India

The data on population ecology of nilgai was collected in Aligarh District, Uttar Pradesh, India from August 2013 to June 2014. A total of 108 herds of nilgai 54 in each season (summer and winter) were encountered, respectively. The density of nilgai was found 0.49/km2 in Aligarh district. While the encounter rate was found 0.66individuals per km. There was a mark seasonal change seen in group size of nilgai i.e. 11.38 ± 2.76, and 22.83 ± 5.40 in winter and summer, respectively. The overall mean group size was found 17.10 ± 4.08. The sex ratio of nilgai was female biased, adult male:adult female ratio was found 1:3 while overall sex ratio was found 61.55%,26.32% and 44% male, yearling and calves on per 100 females, respectively. The nilgai shows mark seasonal change in their group structure. The group size was found maximum at 25% in 0-5 individual category and minimum 9.25 in >21 category in winter, while about 30% were seen in >21 category and only 11% were seen in between 0-5 category in summer season. Thus, the nilgai was found less sociable in winter and more gregarious in summer season.

Nutrient-Induced Modifications of Wood Anatomical Traits of Alchornea lojaensis (Euphorbiaceae)

Regarding woody plant responses on higher atmospheric inputs of the macronutrients nitrogen (N) and phosphorous (P) on tropical forests in the future, an adaptive modification of wood anatomical traits on the cellular level of woody plants is expected. As part of an interdisciplinary nutrient manipulation experiment (NUMEX) carried out in Southern Ecuador, we present here the first descriptive and quantitative wood anatomical analysis of the tropical evergreen tree species Alchornea lojaensis (Euphorbiaceae). We sampled branch wood of nine individual trees belonging to treatments with N fertilization, N+P fertilization, and a control group, respectively. Quantitative evaluations of eleven different vessel parameters were conducted. The results showed that this endemic tree species will be able to adapt well to the future effects of climate change and higher nutrient deposition. This was firstly implied by an increase in vessel diameter and consequently a higher theo. area-specific hydraulic conductivity with higher nutrient availability. Secondly, the percentage of small vessels (0-20µm diameter) strongly increased with fertilization. Thirdly, the vessel arrangement (solitary vessels vs. multiple vessel groupings) changed towards a lower percentage of solitary vessel fraction (VS), and concurrently towards a higher total vessel grouping index (VG) and a higher mean group size of non-solitary vessels (VM) after N and N+P addition. We conclude that higher nutrient availability of N and N+P triggered higher foliage amount and water demand, leading to higher cavitation risk in larger vessels. This is counteracted by a stronger grouping of vessels with smaller risk of cavitation to ensure water supply during drier periods that are expected to occur in higher frequency in the near future.

Occurrence of the Endangered Antillean manatee Trichechus manatus manatus in a marine protected area, Isla de la Juventud, Cuba

AbstractThe Antillean manatee Trichechus manatus manatus is categorized as Endangered on the IUCN Red List but little is known about the status of the species in Cuba. Marine protected areas can contribute to manatee conservation in Cuba but the effectiveness of these areas may be jeopardized by a lack of information regarding appropriate design and management. We developed an index of manatee occurrence in the Fauna Refuge Ciénaga de Lanier, Isla de la Juventud, to assess patterns of manatee use in the reserve. We completed 26 field trips during November 2007–October 2013, with a total of 147 survey days. Manatee presence was detected on 47% of survey days and in 96% of field trips; 133 individuals were recorded in 93 sightings. The index of manatee occurrence varied between trips, suggesting a discontinuous use of the area. The mean group size was 1.4 individuals (range 1–5), and calves were observed in 13% of sightings. Observations of manatee behaviour, occurrence and habitat characteristics indicate the importance of the study area as a resting place, refuge and source of fresh water. We recommend that manatee protection be strengthened to avoid human-related mortality and to ensure that the habitats that provide critical resources are given special consideration in future management plans.

Infectious Disease and Grouping Patterns in Mule Deer.

Infectious disease dynamics are determined, to a great extent, by the social structure of the host. We evaluated sociality, or the tendency to form groups, in Rocky Mountain mule deer (Odocoileus hemionus hemionus) from a chronic wasting disease (CWD) endemic area in Saskatchewan, Canada, to better understand factors that may affect disease transmission. Using group size data collected on 365 radio-collared mule deer (2008–2013), we built a generalized linear mixed model (GLMM) to evaluate whether factors such as CWD status, season, habitat and time of day, predicted group occurrence. Then, we built another GLMM to determine factors associated with group size. Finally, we used 3 measures of group size (typical, mean and median group sizes) to quantify levels of sociality. We found that mule deer showing clinical signs of CWD were less likely to be reported in groups than clinically healthy deer after accounting for time of day, habitat, and month of observation. Mule deer groups were much more likely to occur in February and March than in July. Mixed-sex groups in early gestation were larger than any other group type in any season. Groups were largest and most likely to occur at dawn and dusk, and in open habitats, such as cropland. We discuss the implication of these results with respect to sociobiology and CWD transmission dynamics.

Interspecific association in ungulates of the Bale Mountains National Park, Ethiopia

AbstractThe aim of the study was to determine the frequencies of interspecific association formation and species preferences among five ungulates [bohor reedbuck (Redunca redunca), common warthog (Phacochoerus africanus), grey duiker (Sylvicapra grimmia), Menelik's bushbuck (Tragelaphus scriptus meneliki) and mountain nyala (Tragelaphus buxtoni)] in the northern Bale Mountains National Park, Ethiopia. Data were collected in three forest patches and in open grassland using total count technique in 2009 and 2011. The total number of ungulate groups found in interspecific associations was 444, comprising 26.8% of the total 1657 groups recorded. For the five study species, the relative frequency with which a given species occurred in interspecific association deviated significantly from the expected mean relative frequency (i.e. 26.8%). Each study species showed preferences to form interspecific associations with one or two other species. Interspecific association formation increased mean group sizes for bohor reedbuck and mountain nyala. And most of the species had greater overall mean group sizes in the open habitat compared to forest habitat. In general, the association pattern reported here could be attributed to antipredator response and/or mutual grazing facilitation, which might be beneficial to one or all of the species involved.

Estimating the density of Red Junglefowl Gallus gallus (Galliformes: Phasianidae) in the tropical forest of Similipal Tiger Reserve, eastern India

<p>To determine population status of wild animal using reliable sampling techniques forms an important component of conservation effort and effective wildlife management. We estimated the density of Red Junglefowl <em>Gallus gallus</em><strong><em> </em></strong>using distance sampling, a quantitatively robust technique, in Similipal Tiger Reserve, Odisha, eastern India during September 2012 to May 2013. We laid 27 transects and walked seven to eight times for a total of 390km to obtain the distance sampling data. We used DISTANCE software for analysis. We estimated per km<sup>2 </sup>Red Junglefowl group density as 4.99 and density as 7.64 birds in the intensive study area. Mean group size of Red Junglefowl was 1.48. Our results may prove helpful in planning better management needs and strategies for the survival and conservation of Red Junglefowl in different protected areas.</p><div> </div>

Population Recovery of Nicobar Long-Tailed Macaque Macaca fascicularis umbrosus following a Tsunami in the Nicobar Islands, India.

Natural disasters pose a threat to isolated populations of species with restricted distributions, especially those inhabiting islands. The Nicobar long tailed macaque.Macaca fascicularis umbrosus, is one such species found in the three southernmost islands (viz. Great Nicobar, Little Nicobar and Katchal) of the Andaman and Nicobar archipelago, India. These islands were hit by a massive tsunami (Indian Ocean tsunami, 26 December 2004) after a 9.2 magnitude earthquake. Earlier studies [Umapathy et al. 2003; Sivakumar, 2004] reported a sharp decline in the population of M. f. umbrosus after thetsunami. We studied the distribution and population status of M. f. umbrosus on thethree Nicobar Islands and compared our results with those of the previous studies. We carried out trail surveys on existing paths and trails on three islands to get encounter rate as measure of abundance. We also checked the degree of inundation due to tsunami by using Normalized Difference Water Index (NDWI) on landsat imageries of the study area before and after tsunami. Theencounter rate of groups per kilometre of M. f. umbrosus in Great Nicobar, Little Nicobar and Katchal was 0.30, 0.35 and 0.48 respectively with the mean group size of 39 in Great Nicobar and 43 in Katchal following the tsunami. This was higher than that reported in the two earlier studies conducted before and after the tsunami. Post tsunami, there was a significant change in the proportion of adult males, adult females and immatures, but mean group size did not differ as compared to pre tsunami. The results show that population has recovered from a drastic decline caused by tsunami, but it cannot be ascertained whether it has reached stability because of the altered group structure. This study demonstrates the effect of natural disasters on island occurring species.

Spatial organisation of European badger (Meles meles) in northern Italy as assessed by camera-trapping

Italy is amongst the European countries for which data on badger Meles meles numbers and variation in population size are still too few to assess its conservation status. With the aim of estimating badger density in northern Italy, between February 2013 and March 2014, we extensively surveyed an isolated hilly area for badger setts and assessed group size by monitoring a sample of setts by two sessions of camera-trapping. The size and shape of each home range were assessed from main sett coordinates using the Dirichlet tessellation method. Then, assuming that badger home ranges tend to be delimited by hard boundaries or geographical features, the polygon shapes were successively modified by hand to draw more realistic home ranges. The overall trapping effort was 754 camera trap-days. The number of badger individuals sharing the same sett/entrances was recorded, distinguishing individuals based on the time and hole of emergence and, possibly, tail patterns. Groups consisted of two to four adult individuals, averaging 2.75 badgers/group. Camera-trapping proved to be a cost-effective and time-saving method. Depending on the method used to draw home ranges, in the study area, sett density was 0.34–0.51 sett/km2, whilst badger density was 0.93–1.4 adult individuals/km2. Both sett and badger densities were rather high with respect to most available data for continental Europe. As badger mean group size seems to be rather constant throughout both hilly and plain areas of the River Po basin, sett density may be used as an accurate estimator of badger density throughout this wide area.

Wolf recovery and population dynamics in Western Poland, 2001–2012

Since the mid-twentieth century, under different management regimes (over 20 years of a wolf control program followed by 20 years of trophy hunting), wolves were absent or rare in Western Poland (hereinafter WPL). They became strictly protected in the whole country in 1998 and started to re-settle the vast forests of WPL, far (376 ± 106.5 km) from the source population in eastern Poland. In 2002–2012, the population increased from several to approximately 140 wolves living in 30 family groups, with an annual rate of increase of 38 % (λ = 1.38, SE = 0.10). The area of permanent occurrence increased from 600 to 10,900 km2, with an average density of 1.3 wolves/100 km2. The nearest neighbour distance between wolf territories decreased from 260 to 25 km. In 2001–2005, half of the settlement efforts by wolves failed after 1–2 years whereas in 2006–2009 only one fifth of newly settled wolves failed to persist >2 years. The number of wolves in groups varied from 2 to 9, and the mean group size increased from 1.8 in 2001 to 4.8 in 2012. The survival of pups from May to the end of November was 50 % (the mean number of pups per litter was 5.1 and 2.5, respectively). Of 28 wolves found dead, 65 % were killed by vehicles, 25 % were poached, and 7 % died because of diseases and natural factors. All road casualties were young wolves, most of them male (67 %), hit on roads on average 11.6 km from the centre of the nearest pack. The re-colonisation of WPL started from jump dispersal, which allowed wolves to establish packs in distant locations. As the recovery proceeded, the dispersal pattern shifted to being stratified, a mixture of diffusion and jump dispersal that resulted in the creation of packs in close vicinity to existing groups. After 12 years of re-colonisation, wolves in Western Poland occupied about 30 % of potential suitable habitats.

Estimating density of a rare and cryptic high-mountain Galliform species, the Buff-throated Partridge Tetraophasis szechenyii

Xu, Y., B. Wang, L. Dou, H. Yue, N. Yang, L. Yang, S. Liu, and J. Ran. 2016. Estimating density of a rare and cryptic high-mountain Galliform species, the Buff-throated Partridge Tetraophasis szechenyii. Avian Conservation and Ecology 11(1):10.http://dx.doi.org/10.5751/ACE-00853-110110