Causes of Mortality in Reintroduced Eurasian Lynx in Switzerland

The Veterinary Journal, 2009

The Iberian lynx, (Lynx pardinus), is the most endangered felid in the world. To determine whether sympatric carnivores are reservoirs of pathogens posing a disease risk for the lynx, evidence of exposure to 17 viral, bacterial and protozoan agents was investigated in 176 carnivores comprising 26 free-living lynx, 53 domestic cats, 28 dogs, 33 red foxes (Vulpes vulpes), 24 Egyptian mongooses (Herpestes ichneumon), 10 common genets (Genetta genetta) and 2 Eurasian badgers (Meles meles) in the areas inhabited by the last two populations of Iberian lynx, both in Andalusia (South-Western Spain).

European Journal of Wildlife Research, 2008

The Iberian lynx (Lynx pardinus) is the most endangered felid species in the world. Lynx populations have decreased dramatically in size and distribution in the last four decades, thus becoming increasingly vulnerable to catastrophic events such as epizooties. From 1989 to 2000, serum samples were obtained from 48 free-ranging lynx captured in the Doñana National Park (DNP, n=31) and mountains of Sierra Morena (SM, n=17) in southern Spain. Samples were tested for antibodies against Toxoplasma gondii, feline herpesvirus 1 (FHV-1), feline calicivirus (FCV), feline/canine parvovirus (FPV/CPV), feline coronavirus, feline immunodeficiency virus (FIV), feline leukaemia virus and canine distemper virus (CDV) and for FeLV p27 antigen, to document baseline exposure levels. Antibodies against T. gondii were detected in 44% of lynx, with a significantly greater prevalence in DNP (61%) than in SM (12%). In DNP, prevalence was significantly higher in adult (81%) than in juvenile and sub-adult (41%) lynx, but no such difference was observed in SM. Low prevalences (≤11%) of minimally positive titres were found for FHV-1, FCV and FPV/CPV. This, combined with the lack of evidence for exposure to CDV, FIV and FeLV, suggests that these lynx populations are naïve and might be vulnerable to a disease outbreak in the future. Because of the reduced size of lynx populations, the documented low level of genetic variation (particularly in the DNP population) coupled with the recently documented state of immune depletion in a majority of necropsied lynx, it is important to better understand the threat and potential impact that disease agents might pose for the conservation of this endangered species. Future surveillance programs must include possible disease reservoir hosts such as domestic cats and dogs and other wild carnivores.

Scientific Reports

Despite recent local reintroductions of the Eurasian lynx Lynx lynx in central and north-eastern Poland, the increase in its population was not followed by its westward expansion. To address this problem and restore the lynx population in north-western Poland, 61 captive-born individuals of Baltic population origin were released in the province of Western Pomerania in 2019–2021. Prior to their release, all the animals underwent an adaptation training phase. They were then set free according to a hard-release protocol and subsequently monitored by means of GPS telemetry. In order to assess the short-term reintroduction success, the survival and causes of death of the released individuals were studied as a function of sex, age, training time, and release time and place. The overall survival rate was 71.15%, the median survival time 202 days. Most mortality, due to environmental factors, i.e. scabies (> 200 days) or traffic collisions (< 200 days), was recorded during the first 3...

Biological Conservation, 2006

Hunting Attitudes A B S T R A C T Causes of mortality were described for 245 radio-marked Eurasian lynx (Lynx lynx) in five different Scandinavian study areas. Furthermore, the survival rates and the population growth rates were estimated for three of the study areas where 202 lynx were followed for a total of 314 radio-years. The main causes of mortality in adult Eurasian lynx in all our study areas were overwhelmingly anthropogenic, with starvation, vehicle collisions, intra-and interspecific killing and disease only having a minor role. The mean mortality rates for adults increased from 2% to 17% when hunting and poaching were included,

Journal of Zoo and Wildlife Medicine, 2013

Medical records of 120 Iberian lynx (Lynx pardinus) from the captive breeding population (CBP), 96 of which were older than 1 wk old, were studied from January 2004 to June 2010. From a total of 413 clinical signs recorded, it was possible to obtain a diagnosis in 258 (62.5%). Inappetence, skin wound, and vomiting had the highest incidence. Adult (2 to 6 yr old) and juvenile (1 wk to 1 yr old) animals accounted for most of the clinical signs. Vitamin D toxicosis and intraspecific trauma accounted for 55.4% and 15.1% of the clinical signs, respectively. Renal toxicosis due to the administration of supplements with an excess of vitamin D occurred in 2009 and affected a total of 39 individuals. Intraspecific trauma cases were predominantly observed from sibling aggression. Diet-related conditions consisted of sporadic cases of fatal salmonellosis, dermatophytosis, and gastrointestinal episodes. Suspected idiopathic epilepsy and femoral neck metaphyseal osteopathy were also observed. A total of 15 animals older than 1 wk old died including five vitamin D toxicosis cases and three juveniles due to intraspecific trauma. Mycobacterium bovis was found as a secondary infection in two animals that died from vitamin D toxicosis. Abortions, premature births, and stillbirths accounted for 12 mortalities, and 13 neonatal deaths due to maternal neglect or bacterial sepsis were observed. Data show that improvement of diet-related conditions is a key factor in preserving the health of animals in the CBP. Thus, the control of food and supplement composition, rabbit farm suppliers, and hygiene should be standardized and improved. Furthermore, data recording and diagnostic protocols should be standardized.

Journal of Wildlife Diseases, 2005

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Mammalian Biology, 2016

The combination of intensive persecution, habitat loss and prey deficiency led to the extinction of Eurasian lynx (Lynx lynx) in the Dinaric Mountains at the beginning of the 20th century. In 1973, the population was re-established by reintroducing animals from the Slovakian Carpathian Mountains into Slovenia, from where the animals spread into Croatia and Bosnia and Herzegovina. Since the end of the 20th century the reintroduced population has been decreasing, leading us to investigate the principal causes of mortality. Understanding the causes of the declining lynx population in Croatia and elsewhere is important not only in its own right but also because few studies have examined how large carnivore populations have fared under different management regimes. After reintroduction, the first dead lynx was recorded in Croatia in 1978, and from that year until 2013 a total of 232 deaths were recorded. Annual mortality during this period averaged 6.4 deaths per year, ranging from 0 to 17. The number of dead lynxes found every year in the period before the legal protection (1978-1998) was significantly higher than the number of dead animals found in the period after the legal protection (1998-2013). The vast majority of deaths were human-related (92.7%), with only 2.1% not human-related; while the cause of the remaining 5.2% of deaths was undetermined. Shooting was the most dominant cause of death (73.7%), with significantly more males being killed by shooting than females, and significantly more animals shot before the legal protection. Between 1978 and 1998, the year when the lynx became legally protected in Croatia, 10 deaths due to poaching were recorded, accounting for 5% of all deaths in that period and an average of 0.48 poaching cases per year. During 1999-2013, 18 poaching deaths occurred, accounting for 60% of all deaths in that period and an average of 1.2 poaching cases per year. Our findings suggest that the synergy of human-induced mortality, concomitant reduction in genetic variation and possibly prey deficiency may be the principal factors behind the decline in the reintroduced lynx population in Croatia since the end of the 20th century.

Journal of Wildlife Diseases, 2006

As part of a species recovery program, 129 Canada lynx (Lynx canadensis) originating from British Columbia, the Yukon, Manitoba, and Quebec, Canada, and Alaska, USA, were reintroduced to southwestern Colorado, USA, from 1999 to 2003. Of 52 lynx mortalities documented by October 2003, six lynx, including a female and her 5-mo-old kitten, had evidence of Yersinia pestis infection as determined by fluorescent antibody test and/ or culture. Postmortem findings in these lynx were characterized by pneumonia, ranging from acute suppurative pneumonia, to multifocal necrotizing pneumonia, to fibrinous bronchopneumonia. Histopathologic examination of lung revealed multiple areas of inflammation and consolidation, areas of edema and hemorrhage, and bacteria surrounded by extensive inflammation. Spleens had severe lymphoid depletion and hypocellular red pulp. Lymphadenomegaly was observed in only one plagueaffected lynx. We hypothesize that these Canada lynx were exposed to Y. pestis by infected prey, and these are the first reports of plague in this species.

Ecological Complexity, 2015