Reproductive collapse in saiga antelope harems

Milner‐Gulland, E. J.; Bukreeva, O. M.; Coulson, Tim; Лущекина, А. А.; Холодова, М. В.; Bekenov, A. B.; Grachev, Iu. A.

doi:10.1038/422135a

Cited by 226 publications

(233 citation statements)

References 6 publications

Supporting

Mentioning

229

Contrasting

Unclassified

Order By: Relevance

“…Reduced female reproductive success via sperm limitation has been documented in some large male-only fished crab populations (e.g. Paralithodes brevipes, Sato et al 2007;Callinectes sapidus, Carver et al 2005; but see Cancer magister, Hankin et al 1997) and population crashes in ungulate populations have been attributed to reduced fecundity due to selective harvesting of large males (Milner-Gulland et al 2003, Milner et al 2007). However, apart from in the above mentioned populations, the negative effects of large male-selective harvesting on the reproductive rate of resources have received far less attention than the direct effect of harvesting on abundance of many species.…”

Section: Introductionmentioning

confidence: 99%

Sperm limitation: possible impacts of large male-selective harvesting on reproduction of the coconut crab Birgus latro

Sato

Yoseda²,

Okuzawa³

et al. 2010

Aquat. Biol.

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Sperm limitation: possible impacts of large male-selective harvesting on reproduction of the coconut crab Birgus latro

Sato

Yoseda²,

Okuzawa³

et al. 2010

Aquat. Biol.

View full text Add to dashboard Cite

“…For example, the culling of large males will reduce female population growth rate if males limit ewe fecundity (see ref. 10) or through reduction of female survival or female lambs that are born smaller owing to inheritance. We do not find evidence of male mortality influencing female fecundity or survival here.…”

Section: Significancementioning

confidence: 99%

“…If the trait is heritable, then selection against the character can result in a cross-generational decrease in the character mean (1,6,7). Apparent shifts in the distribution of a quantitative character, however, may not occur through genetic mechanisms alone, because hunting can also alter age and sex structure, behavior, and social hierarchies (8)(9)(10), which may in turn interact with localized density-dependent and -independent factors to accentuate, or mask, a phenotypic response (6,11,12).…”

mentioning

confidence: 99%

Demography, not inheritance, drives phenotypic change in hunted bighorn sheep

Traill

Schindler

Coulson

2014

Proc. Natl. Acad. Sci. U.S.A.

107

View full text Add to dashboard Cite

Selective harvest, such as trophy hunting, can shift the distribution of a quantitative character such as body size. If the targeted character is heritable, then there will be an evolutionary response to selection, and where the trait is not, then any response will be plastic or demographic. Identifying the relative contributions of these different mechanisms is a major challenge in wildlife conservation. New mathematical approaches can provide insight not previously available. Here we develop a size-and age-based two-sex integral projection model based on individual-based data from a long-term study of hunted bighorn sheep (Ovis canadensis) at Ram Mountain, Canada. We simulate the effect of trophy hunting on body size and find that the inheritance of body mass is weak and that any perceived decline in body mass of the bighorn population is largely attributable to demographic change and environmental factors. To our knowledge, this work provides the first use of twosex integral projection models to investigate the potential ecoevolutionary consequences of selective harvest.T rophy hunting, can result in undesirable phenotypic change (1, 2), sometimes termed "unnatural selection" (3). Hunters may target individuals within a population that possess a trait they seek, such as large body or horn size, or a distinct color morph (4-6). If the trait is heritable, then selection against the character can result in a cross-generational decrease in the character mean (1, 6, 7). Apparent shifts in the distribution of a quantitative character, however, may not occur through genetic mechanisms alone, because hunting can also alter age and sex structure, behavior, and social hierarchies (8-10), which may in turn interact with localized density-dependent and -independent factors to accentuate, or mask, a phenotypic response (6,11,12).To date, there have been some generalizations that hunting management can follow in an attempt to mimic natural mortality and limit selection against desirable traits, such as nose coloration for African lions (13). Where long-term data are available for hunted populations, then a response to unnatural selection can be detected. One relatively new method that provides a broad model framework, within which scenario tests are possible, is integral projection modeling (14, 15). These models are built from the relationships between a continuous quantitative trait such as body mass and demographic functions. Integral projection models (IPMs) are constructed from the statistical relationships between a trait and survival and fecundity, development of the trait over time, and the pattern of inheritance (15). IPMs can be used to calculate quantities useful to population and evolutionary biologists, including population structure and growth rate, net reproductive rate, generation length, and estimates of biometric heritabilities (16). IPMs also avoid the discrete classes of classic matrix models, although they can be approximated as high-dimensional matrices.Recent theoretical development has provided for ...

show abstract

“…The few data available regarding juvenile and adult sex ratios in marine turtles suggest that the female biases seen at hatching are maintained at older life stages ( [17,18] but see [19]), hence, a climate-induced increase in female-biased primary sex ratios could threaten the viability of marine turtle populations through a reduction in N e and associated genetic effects, and potential reproductive failure owing to scarcity of males. These consequences are expected to be particularly deleterious in small populations, where the number of males could conceivably be reduced to below a critical minimum required to maintain a fertile population [9], and in areas where incubation temperatures already result in extremely female-biased offspring production [7]. Larger populations, and those that encompass rookeries at nesting range extremes where more males are produced, may be more robust to offspring sex ratio skews [4], except under the most extreme climate-change scenarios.…”

Section: Introductionmentioning

confidence: 99%

“…Future climate change scenarios are predicted to increase these sex ratio biases, with implications for population viability [2,3,6,7]. Potential consequences include a reduction in effective population size (N e ) that will exacerbate the negative effects of inbreeding and increase genetic drift in small populations [8], the inability to find mates leading to reduced fecundity or female infertility [9], and, under more extreme climate projections, the production of single sex cohorts [3,7].…”

Section: Introductionmentioning

confidence: 99%

Turtle mating patterns buffer against disruptive effects of climate change

et al. 2012

View full text Add to dashboard Cite

For organisms with temperature-dependent sex determination (TSD), skewed offspring sex ratios are common. However, climate warming poses the unique threat of producing extreme sex ratio biases that could ultimately lead to population extinctions. In marine turtles, highly female-skewed hatchling sex ratios already occur and predicted increases in global temperatures are expected to exacerbate this trend, unless species can adapt. However, it is not known whether offspring sex ratios persist into adulthood, or whether variation in male mating success intensifies the impact of a shortage of males on effective population size. Here, we use parentage analysis to show that in a rookery of the endangered green turtle (Chelonia mydas), despite an offspring sex ratio of 95 per cent females, there were at least 1.4 reproductive males to every breeding female. Our results suggest that male reproductive intervals may be shorter than the 2 -4 years typical for females, and/or that males move between aggregations of receptive females, an inference supported by our satellite tracking, which shows that male turtles may visit multiple rookeries. We suggest that male mating patterns have the potential to buffer the disruptive effects of climate change on marine turtle populations, many of which are already seriously threatened.

show abstract

Reproductive collapse in saiga antelope harems

Cited by 226 publications

References 6 publications

Sperm limitation: possible impacts of large male-selective harvesting on reproduction of the coconut crab Birgus latro

Sperm limitation: possible impacts of large male-selective harvesting on reproduction of the coconut crab Birgus latro

Demography, not inheritance, drives phenotypic change in hunted bighorn sheep

Turtle mating patterns buffer against disruptive effects of climate change

Contact Info

Product

Resources

About