同胞侵犯对猞猁幼仔行为的影响

研究了非自由生活的4窝11只猞猁幼仔的玩耍行为、亲和及入侵关系的变化.观察到36-57日龄幼仔的同胞打斗行为,这些打斗减少了这些幼仔之间游戏性接触的频次.这个"打斗期"与游戏行为和食性的变化同步发生.打斗后,幼仔游戏性接触的非对称性以及同胞之间的偏爱更加清楚.这些打斗导致了不同窝的幼仔之间等级结构的建立.     

Genotyping success of historical Eurasian lynx (Lynx lynx L.) samples

Historical samples, like tanned hides and trophy skulls, can be extremely important for genetic studies of endangered or elusive species. Selection of a sampling protocol that is likely to provide sufficient amount and quality of DNA with a minimum damage to the original specimen is often critical for a success of the study. We investigated microsatellite genotyping success of DNA isolated from three different types of Eurasian lynx historical samples. We analysed a total of 20 microsatellite loci in 106 historical samples from the endangered Dinaric lynx population, established from re-introduction of three pairs of lynx in 1973 from Slovakian Carpathians. Of the three tested sample types, turbinal bone and septum from the nasal cavity of the trophy skulls had the lowest percentage of samples successfully genotyped for all 20 microsatellite loci. Footpad samples, collected using a cork drill, exhibited better results in polymerase chain reaction amplification and genotyping than samples of footpad epidermis cut with a scalpel. We report simple and efficient sampling protocols, which could be widely applied for future studies utilizing historical samples.     

猞猁在云南省野外分布的首例影像记录

<正>猞猁(Lynx lynx Linnaeus, 1758)为食肉目(CARNIVORA)猫科(Felidae)猞猁属(Lynx)的中等体型哺乳动物,主要分布于欧洲、北亚、西亚及中亚地区(蒋志刚等,2015)。猞猁分布较广,数量多,为IUCN红色名录的无危物种(Least Concern, LC)(Breitenmoser et al., 2015)。亚洲地区的猞猁主要栖息在山地森林、无林裸岩地带、密集灌木丛和草原,分布海拔可达4 500 m (汪松,1998)。在中国,猞猁分布于东北、华北、西北和西南地区(高耀亭等,1987;王应祥,2003),野外种群数量较少,属于国家二级重点保护野生动物,     

Reproductive biology of captive female Eurasian lynx, Lynx lynx

Studies on wild Eurasian lynx (Lynx lynx) have revealed variation in reproduction between areas, years and individuals. In order to explore potential causes for this variation other than food supply, we analysed data from captive lynx, which provide conditions with minimal environmental variation as all were fed ad libitum. Data from 37 individual female lynx were available from 20 zoos in Norway, Sweden, Finland, Switzerland and the Czech Republic. Data on 177 reproductive events (where a male was available to the female at mating time) are presented. Of these events, 85% resulted in litters being born. Average litter size was 1.95, with a variation from 1 to 4. The mean birth date was 26th May, and sex ratio was not significantly different from parity. The probability of reproduction was related to age, with fewer litters produced by the very young (2–3-year old), and no sign of a senescence effect. However, a clear effect of senescence on litter size was evident. The captive lynx did not have higher reproductive rates than wild lynx, indicating that either factors other than food supply are driving the variation in wild lynx reproduction, or that a factor such as stress may be causing additional variation in the captive population.     

Risk taking by Eurasian lynx (Lynx lynx) in a human-dominated landscape: effects of sex and reproductive status

This study aimed to test how the sex and reproductive status of Eurasian lynx influenced their use of 'attractive sinks'– habitats with high prey density and high mortality risks. Locations of 24 Eurasian lynx Lynx lynx were obtained by radio-telemetry in a mixed forest and agricultural habitat in south-eastern Norway. Roe deer, the major food source of lynx in the study area, occurred at higher densities closer to areas of human activity and infrastructure. Proximity of lynx locations to human activity and infrastructure was used as a risk index because the most common causes of death among Scandinavian lynx were of anthropogenic origin. This study shows that distances from lynx locations to human activity were significantly greater for females with newborn kittens than for males, but this decreased with kitten age. The data suggest that this response to human activity is influenced by the reproductive strategies of males and females, and might explain male-biased human-induced mortality in this study and in carnivores more generally.     

Cryptic population structuring in Scandinavian lynx: reply to Pamilo

In a recent Commentary in this journal, Pamilo (2004) criticized our analysis of the spatial genetic structure of the Eurasian lynx in Scandinavia (Rueness et al. 2003). The analyses uncovered a marked geographical differentiation along the Scandinavian peninsula with an apparent linear gradient in the north-south direction. We used computer simulations to check on the proposition that the observed geographical structure could have arisen by genetic drift and isolation by distance in the approximate 25 generations that have passed since the last bottleneck. Pamilo disapproved of our choice of population model and also how we compared the outcome of the simulations with data. As these issues should be of interest to a wider audience we discuss them in some detail.     

Bifurcations and chaos in ecology: lynx returns revisited

One of the most popular data sets in ecology, that of lynx fur returns, is analysed in order to look for evidence for a bifurcation process. This bifurcation seems to be present from the observation of sudden shifts in the amplitude of oscillations of the lynx time series. Schaffer first proposed the possibility for such a bifurcation in 1985, and suggested that a possible source for the qualitative change of lynx's fluctuations was an increased trapping effort, which eventually lead to high-amplitude, chaotic dynamics. By studying the available information from the Hudson Bay Company records, we have found evidence for such an increased trapping pressure that (i) rapidly rose close to the shift from low-amplitude to large-amplitude fluctuations around 1820, and (ii) decreased around 1910, when there is another shift again to damped small oscillations. Although an increase in the top-predator mortality in a three-species food web typically leads to simpler dynamics and eventual predator extinction, here we show that a recent model involving a minimum bound in the lynx population, due to the presence of alternative prey in the lynx diet, consistently supports the presence of a bifurcation phenomenon.     

Lynx (Lynx lynx) killing red foxes (Vulpes vulpes) in boreal Sweden – frequency and population effects

We studied the frequency and pattern of lynx Lynx lynx predation on red foxes Vulpes vulpes in boreal Sweden by the radio tracking of foxes and the snow tracking of lynx. We also assessed the population trend of red foxes after the re-establishment of lynx in the region, based on various population indices. Fifty per cent of recorded fox mortalities in the radio-tracking study (four of eight) were lynx kills. Adult-sized foxes killed by lynx during radio tracking were in normal condition and of prime age, and were killed after the assumed annual population bottleneck. Albeit based on a small number of kills, this pattern may suggest that lynx predation, at least to some extent, is additive to other mortality in foxes. The annual lynx predation rate was 14% on radio-tracked foxes and 4% on snow-tracked foxes. The population indices of foxes in the main study area decreased by about 10% annually during the study period. The population decrease could potentially be explained by lynx predation alone, but we acknowledge some alternative explanations. Our results point out the possibility that red fox populations can be significantly limited by allowing lynx populations to recover.     

猞猁肝脏的组织结构观察及EGF在肝脏中的表达

利用切片方法观察了猞猁Felislynx肝脏的组织结构,应用免疫组织化学方法检测了表皮生长因子(EGF)在肝脏中的表达。结果显示,肝脏外被覆一层结缔组织薄膜,肝小叶不规则且分界不清,肝板、肝血窦及狄氏间隙围绕中央静脉呈放射状排列,肝板由一排肝细胞构成。肝细胞呈圆形或多边形,多为单核,少数具双核,肝细胞间比较松散。肝血窦发达,内可见血细胞。EGF阳性反应主要定位于肝细胞质中,表明EGF可能参与细胞新陈代谢过程的调控。     

Management measures to control a feline leukemia virus outbreak in the endangered Iberian lynx

The feline leukemia virus (FeLV) is a retrovirus that affects domestic cats all over the world. Its pathogenic effects generally include anemia, immunosuppression or tumors. Dissemination over populations is linked to cat sociality, because the virus is transmitted by direct contact. Although the domestic cat is its common host, FeLV infection has also been described in some wild felids. In the Iberian lynx Lynx pardinus , some sporadic FeLV infection cases have been reported since 1994, but an outbreak with the involvement of several animals has never been described until now. During spring 2007, an FeLV outbreak hit the Doñana (SW Spain) population. The infection rapidly spread throughout the densest subpopulation throughout Doñana. Infected animals showed very acute anemic disease, most of them dying in <6 months. To avoid FeLV dissemination, a control program was carried out that included removal of viremic lynxes, vaccination of negative individuals and reduction of the feral cat population. The program was implemented both in Doñana and in Sierra Morena populations. In Doñana, around 80% of the total lynx population and 90% of the outbreak focus subpopulation were evaluated. Seven out of the 12 infected individuals found died and two reverted to latency; the remaining viremic animals have been kept in captivity. The outbreak appears to have been successfully confined to the subpopulation where the virus appeared and no more cases have been found since August 2007. In the larger Sierra Morena population, 8% of the lynx population was surveyed. Thirty-four uninfected Iberian lynxes were vaccinated at least once. The FeLV prevalence was found to be 27% in the Doñana population and 0% in the Sierra Morena population.     

Cryptic population structure in a large,mobile mammalian predator: the Scandinavian lynx

The Eurasian lynx (Lynx lynx) is an example of a species that has gone through a severe bottleneck, leading to near extinction in Scandinavia around 1930-- a pattern shared with several other large carnivorous mammals. Here we extend previous genetic analyses of northern European lynx, confirming that lynx from the Scandinavian Peninsula represent a distinct clade differing clearly from European conspecifics. Furthermore, and despite a recent bottleneck and subsequent range expansion, we detect marked genetic differentiation within Scandinavia. This differentiation is largely manifested as a north-south gradient, with a linear increase in the quantity FST/(1 - FST). Aided by computer simulations we find that this pattern is unlikely to have arisen by random genetic drift in the short time since lynx started to expand in the 1950s, suggesting that the spatial structure may predate the bottleneck. Individual-based analyses indicate that, instead of a continuous gradient, Scandinavian lynx may be structured into three more or less distinct groups, possibly corresponding to northern, central and southern subpopulations. The presence of such structuring was unknown previously and was unexpected from general considerations on the mobility of the species, historical data and the absence of geographical barriers. Our study demonstrates how molecular markers may be used to detect cryptic population structure, invisible using traditional methods.     

Seven decades of southern range dynamics of Canada lynx

The range of the Canada lynx (Lynx canadensis) has contracted substantially from its historical range. Using harvest records, we found that the southern range of the lynx in Ontario in the late 1940s collapsed and then, in a short period of time, increased to its largest extent in the mid‐1960s when the lynx range spread south of the boreal forest for a decade. After this expansion, the southern range contracted northwards beginning in the 1970s. Most recently, there has been a slight expansion between 2010 and 2017. We have attributed these dynamics on the southern range periphery to the fluctuation of the boreal lynx population in the core of the species'' range. In addition, connectivity to boreal lynx populations and snow depth seemed to condition whether the lynx expanded into an area. However, we did not find any evidence to suggest that these changes were due to anthropogenic landscape disturbances or competition. The boreal lynx population does not reach the peak abundance it once did, without which we would not expect to see large expansions of the southern lynx range as in the mid‐1960s. Our results suggest that the southern lynx range in Ontario has been driven by the magnitude of the boreal lynx population cycle, connectivity to the boreal forest, and snow conditions. Future persistence of lynx in the southern range periphery will likely depend on dynamics in the range core.     

Fine‐scale habitat selection by sympatric Canada lynx and bobcat

The Canada lynx (Lynx canadensis) and the bobcat (Lynx rufus) are closely related species with overlap at their range peripheries, but the factors that limit each species and the interactions between them are not well understood. Habitat selection is a hierarchical process, in which selection at higher orders (geographic range, home range) may constrain selection at lower orders (within the home range). Habitat selection at a very fine scale within the home range has been less studied for both lynx and bobcat compared to selection at broader spatiotemporal scales. To compare this fourth‐order habitat selection by the two species in an area of sympatry, we tracked lynx and bobcat during the winters of 2017 and 2018 on the north shore of Lake Huron, Ontario. We found that both lynx and bobcat selected shallower snow, higher snowshoe hare abundance, and higher amounts of coniferous forest at the fourth order. However, the two species were spatially segregated at the second order, and lynx were found in areas with deeper snow, more snowshoe hare, and more coniferous forest. Taken together, our findings demonstrate that the lynx and bobcat select different resources at the second order, assorting along an environmental gradient in the study area, and that competition is unlikely to be occurring between the two species at finer scales.