Erhebung über die Wildverluste durch den Straßenverkehr und die Verkehrsunfälle durch Wild

et al. 2020

Animals

This work summarizes the mortality cases of twenty-five free-ranging Eurasian wild brown bears (Ursus arctos arctos) from the Cantabrian mountain range submitted for necropsy in Asturias and Castilla y León (northwestern Spain) from 1998 to 2018. Mortality cases were classified both caused by (i) “non-human intervention” or “human intervention” causes and based on (ii) “non-infectious” or “infectious” etiology. In four cases (16%) it was not possible to determine the cause of death due to the inadequate preservation of collected specimens or insufficient tissue availability. Based on “non-human intervention” or “human intervention” causes, fourteen of the 21 (66.7%) brown bears died as a consequence of “non-human intervention” due to traumatic lesions (fights, unknown traumas or infanticide), infectious canine hepatitis, neoplasia or mushroom poisoning. In contrast, seven (33.3%) brown bears died by “human intervention” due to illegal hunting (shooting or snare), handling (during transit in an attempt to reintroduce a bear back into the wild) or strychnine poisoning. Based on “non-infectious” or “infectious” etiology, twelve of the 21 (57.1%) brown bears died due to “non-infectious” causes, namely traumatic lesions such as shooting, snare, fighting or infanticide, handling, strychnine poisoning, mushroom poisoning or neoplasia. The remaining nine (42.9%) animals died due to “infectious” diseases which included gangrenous myositis, infectious canine hepatitis or septicemia. In six of those cases traumatic lesions caused by non-human or human activities were complicated with bacterial infection (clostridiosis and septicemia) which finally caused the death of those animals. Additionally, exertional myopathy was observed in the handled animal and in one bear found in a snare. In a free-ranging population of Eurasian brown bear from the Cantabrian mountain range, main causes of death are attributed to non-human related traumatic lesions and infectious diseases (primary developed such as infectious canine hepatitis or secondary developed such as clostridiosis or septicemia) which is in contrast to previously reported data for other bear populations. These data are valuable and may help in the conservation and management of this recovering population.

Section: Discussionmentioning

confidence: 99%

Mortality Causes in Free-Ranging Eurasian Brown Bears (Ursus arctos arctos) in Spain 1998–2018

et al. 2020

Animals

“…Tra c induced bear mortality has been documented as a common cause of death in bears in other European countries [4,[19][20][21][22][23][24][25][26]. In our study we have not reported any road-killed animals, despite one bear that died in a tra c accident (the only one reported in Spain to date) in León in 2008, although necropsy of this bear was not performed, and it is not included in this report [27].…”

Section: Discussionmentioning

confidence: 99%

Mortality in free-ranging Eurasian brown bears (Ursus arctos arctos) in Spain '1998-2018'

et al. 2020

Preprint

Background: This work summarizes the mortality cases of twenty-five free-ranging Eurasian wild brown bears (Ursus arctos arctos) from the Cantabrian mountain range submitted for necropsy in Asturias and Castilla y León (northwestern Spain) from ' 1998 to 2018'. Results: Causes of death were classified both caused by (i) "human intervention" or "natural causes" and based on (ii) "infectious" or "non-infectious" etiology. In four cases (16%) it was not possible to determine the cause of death due to the inadequate preservation of collected specimens or insufficient tissue availability. Based on "human intervention" or "natural causes", seven out of the 21 (33.3%) brown bears in which the cause of death could be determined died as a consequence of "human intervention" due to illegal hunting (shooting or snare), handling or strychnine poisoning. In contrast, fourteen (66.7%) brown bears died by "natural causes" due to traumatic lesions (fights, unknown traumas or infanticide), infectious canine hepatitis, neoplasia, or mushroom poisoning. Based on "infectious" or "non-infectious" etiology nine out of the 21 (42.9%) brown bears died due to "infectious diseases", namely gangrenous myositis, infectious canine hepatitis or septicemia. The remaining twelve (57.1%) animals died due to "non-infectious" causes, which included handling, traumatic lesions such as shooting, snare, fighting or infanticide, strychnine poisoning, mushroom poisoning or neoplasia. In six of those cases traumatic lesions caused by human activities or by natural causes were complicated with bacterial infection (clostridiosis and septicemia) which finally caused the death of those animals. Additionally, exertional myopathy was observed in the handled animal and in one bear found in a snare. Conclusions: In a non-hunted population of Eurasian brown bear from the Cantabrian mountain range, main cause of death is attributed to “natural causes” mostly due to traumatic lesions and infectious diseases (primary developed such as infectious canine hepatitis or secondary developed such as clostridiosis or septicemia) which is in contrast to previously reported data for other bear populations.These data are valuable and may help in the conservation and management of this recovering population.

“…Therefore that should be taken into account in the management of bears. The acute presentation of adrenal hypoplasia shown in the cub could be precipitated by the physiologic stress suffered [13]. Nevertheless, the confirmation of six out of 25 brown bears submitted to the laboratory for necropsy confirmed as death by shooting, snare and poisoning (4 of them from 1998 to 2008 and two from 2008 onwards) seems to agree with the apparent reduction in illegal killing after the mid-nineties [1,14], suggested as a key factor for the recovery undergone during last two decades [2].…”

Section: Discussionmentioning

confidence: 99%

Mortality in free-ranging Eurasian brown bears (Ursus arctos arctos) in Spain (1998-2018)

et al. 2020

Preprint

Background This work summarizes the confirmed causes of death of twenty-five free-ranging Eurasian brown bears ( Ursus arctos arctos ) from the Cantabrian mountain range submitted for necropsy in Asturias and Castilla y León (northwestern Spain) from 1998 to 2018. Results Causes of death were classified based on (i) pathological findings and (ii) caused by “human intervention” or “non human intervention”. In four cases (16%) it was not possible to determine the cause of death due to the bad preservation of found remains or insufficient tissue availability. Based on pathological findings seven out of the 21 (33.3%) brown bears in which the cause of death could be determined died due to infectious diseases (clostridiosis n =4 or infectious canine hepatitis n =3), two (9.5%) due to exertional (degenerative) myopathy (one of those bears also showed clostridiosis) and one due to strychnine poisoning (4.8%), neoplasia (4.8%) or mushroom poisoning (4.8%). The remaining animals died due to traumatic lesions (including fights or infanticide), shooting or wire snare. Mortality data was also classified by deaths caused by “human intervention” or “non human intervention”. The death of one bear showing exertional myopathy after handling was not ascribed to any of the former classifications. Six out of the 20 (30%) brown bears died as a consequence of “human intervention” due to illegal hunting (wire snare hunting n =3 or shooting n =2) and, strychnine poisoning ( n =1). In contrast, fourteen (14/20, 70%) brown bears died by “non-human intervention”; nine of them (9/20, 45%) due to traumatic lesions (fights n =4, traumas n =3 or infanticide n =2), three (3/20, 15%) due to infectious canine hepatitis caused by canine adenovirus type 1 (CAdV-1) infection, one (1/20, 5%) due to cholangiocarcinoma and another one (5%) due to mushroom poisoning. Conclusions This study shows that the main causes of death in Eurasian brown bears are those caused by infectious diseases. In contrast to previous data on free-ranging bears for the first time infectious diseases appear as an important cause of death. These data are valuable and may help in the conservation and management of this recovering population.