Litter size, sex ratio, and age structure of gray wolves, Canis lupus, in relation to population fluctuations in northern Belarus

Sidorovich, Vadim E.; Stolyarov, V. P.; Vorobei, N.N.; Ivanova, N. V.; Jędrzejewska, Bogumiła

doi:10.1139/z07-001

Cited by 36 publications

(24 citation statements)

References 15 publications

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“…Our results might indicate a population-level response to territory vacancies and per capita food availability. Similar inversely density-dependent effects have been reported for grey wolf Canis lupus, with litter sizes increasing with declining density due to higher availability of food (Rausch, 1967;Sidorovich, Tikhomirova & Jedrzejewska, 2003;Sidorovich et al, 2007).…”

Section: Discussionsupporting

confidence: 76%

Inbreeding and density‐dependent population growth in a small, isolated lion population

Trinkel

Funston

Hofmeyr

et al. 2010

Animal Conservation

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In South Africa, more than 30 small, enclosed game reserves have reintroduced lions over the last two decades, which now house more than 500 individuals. There is a high risk of inbreeding in these fragmented, fenced and isolated populations, which may be compounded by a lack of management guidelines. A population of 11 founder lions Panthera leo was reintroduced to Madikwe Game Reserve in 1995, and this population has in turn become a source for reestablishing other populations. Only four lineages were reintroduced, founder males were related to founder females, and since 1997, only one male lineage maintained tenure for 49 years, resulting in breeding with direct relatives. Interventionist management to limit lion population growth and inbreeding in Madikwe has taken the form of translocating, trophy hunting and culling of mainly sub adult lions. Despite this management, inbreeding started 5 years after reintroduction. Reproductive performance and thus population growth in Madikwe were dependent on the overall lion population density. When lion density was low, females first gave birth at a significantly younger age and produced larger litters, resulting in a high population growth rate, which decreased significantly when lion density in the park reached carrying capacity, that is, 61 lions. This might have profound consequences for future reestablishment of lion populations when restocking new reserves: our study illustrates the need for founder populations of reintroduced endangered predator species to be as large and genetically diverse as possible, and thereafter new genetic material should be supplemented. The development of such management guidelines is becoming very important as large predator populations become increasingly fragmented and managed as metapopulations.

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Section: Discussionsupporting

confidence: 76%

Inbreeding and density‐dependent population growth in a small, isolated lion population

Trinkel

Funston

Hofmeyr

et al. 2010

Animal Conservation

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“…The average age of tundra–taiga wolves in our study (2·0 years) was intermediate to the average ages of 1·5 and 2·8 years reported in a comparable study during periods of high and low hunting pressure, respectively (Sidorovich et al . ). Similarly, the proportion of tundra–taiga wolves <1 year old in our study (39%) was intermediate to proportions of 55% and 34% reported during periods of high and low hunting (Sidorovich et al .…”

Section: Discussionmentioning

confidence: 97%

“…Similarly, the proportion of tundra–taiga wolves <1 year old in our study (39%) was intermediate to proportions of 55% and 34% reported during periods of high and low hunting (Sidorovich et al . ). This comparison suggests that tundra–taiga wolves could have a skewed age structure and higher proportion of juveniles relative to populations with lower hunting pressure.…”

Section: Discussionmentioning

confidence: 97%

Heavily hunted wolves have higher stress and reproductive steroids than wolves with lower hunting pressure

et al. 2014

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Summary1. Human-caused harassment and mortality (e.g. hunting) affects many aspects of wildlife population dynamics and social structure. Little is known, however, about the social and physiological effects of hunting, which might provide valuable insights into the mechanisms by which wildlife respond to human-caused mortality. 2. To investigate physiological consequences of hunting, we measured stress and reproductive hormones in hair, which reflect endocrine activity during hair growth. Applying this novel approach, we compared steroid hormone levels in hair of wolves (Canis lupus) living in Canada's tundra-taiga (n = 103) that experience heavy rates of hunting with those in the northern boreal forest (n = 45) where hunting pressure is substantially lower. 3. The hair samples revealed that progesterone was higher in tundra-taiga wolves, possibly reflecting increased reproductive effort and social disruption in response to human-related mortality. Tundra-taiga wolves also had higher testosterone and cortisol levels, which may reflect social instability. 4. To control for habitat differences, we also measured cortisol in an out-group of boreal forest wolves (n = 30) that were killed as part of a control programme. Cortisol was higher in the boreal out-group than in our study population from the northern boreal forest. 5. Overall, our findings support the social and physiological consequences of human-caused mortality. Long-term implications of altered physiological responses should be considered in management and conservations strategies.

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“…Yet, in our case study, the sex ratio obtained from camera traps was closer to 1 M:1 F than the sex ratio obtained from genetic identification (2.7 M:1 F). The sex ratio is alleged to be close to one (Kreeger 2003), even though there is some evidence of a possible bias towards males in adult wolves (Mech 1970) or towards female pups in low-density populations (Sidorovich et al 2007). A slight prevalence of male genotypes has been detected in other NGS studies in Italy Marucco et al 2009).…”

Section: Discussionmentioning

confidence: 98%

Monitoring wolves (Canis lupus) by non-invasive genetics and camera trapping: a small-scale pilot study

et al. 2011

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Monitoring populations of elusive large carnivores like wolves (Canis lupus), which are often distributed at low density in widespread forested areas, is difficult or exceedingly expensive. Aiming to assess the power of two indirect monitoring methods, non-invasive genetic sampling and camera trapping, we designed a small-scale pilot study that was carried out from 2006 to 2008 in and around the Corno alle Scale Regional Park, Bologna, northern Italian Apennine. We collected 103 non-invasive samples (mainly scats) that were genotyped at 12 microsatellite loci and sexed using the ZFX gene. We identified 11 distinct wolf genotypes within the park and four wolf genotypes outside. Spatial locations and kinship analyses showed that the wolves belong to three different packs. The breeding pair of the 'Park' pack showed a complete turnover in the two sampling seasons. Two dogs, but no hybrids, were identified in the area. Up to five unbaited camera traps were activated (for 1,250 trapping-nights) close to recent wolf presence marks. We obtained 103 photos of wolves, documenting the reproduction events, the minimum number of adult and young wolves, and phenotype information each year. We obtained information on health conditions detecting probable sarcoptic mange in three individuals. Camera trapping also showed that the presence of wolves in a chase area during wild boar (Sus scrofa) hunting sessions was significantly higher in the nights just after a chase (P< 0.01, χ 2 test; P<0.07¸exact Fisher test). The data obtained from genetics and camera trapping were consistent with one other, and in part complementary. The total cost of the study (c. 28,000 €) was moderate, suggesting that this integrated approach can be successfully used to monitor the structure and dynamics of local wolf packs.

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Litter size, sex ratio, and age structure of gray wolves, Canis lupus, in relation to population fluctuations in northern Belarus

Cited by 36 publications

References 15 publications

Inbreeding and density‐dependent population growth in a small, isolated lion population

Inbreeding and density‐dependent population growth in a small, isolated lion population

Heavily hunted wolves have higher stress and reproductive steroids than wolves with lower hunting pressure

Monitoring wolves (Canis lupus) by non-invasive genetics and camera trapping: a small-scale pilot study

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