Allometric Scaling and Bayesian Priors for Annual Survival of Birds and Mammals

McCarthy, Michael A.; Citroen, Rebecca; McCall, Sarah C.

doi:10.1086/588074

Cited by 53 publications

(75 citation statements)

References 24 publications

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“…Unfortunately, such data are typically unavailable for many harvested populations in developing nations, particularly across sub-Saharan Africa, despite the importance of the trophy-hunting industry to local African economies (25). In the absence of longitudinal data, then, informative priors based on allometrically scaled body sizedemographic rate associations (26) or published demographic rates (27) may be used to parameterize IPMs, but we strongly suspect that the effects of harvest are localized (28) and that models based on longitudinal, individual-based data (see ref. 29) will be most appropriate for decision making.…”

Section: Discussionmentioning

confidence: 99%

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

Traill

Schindler

Coulson

2014

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

107

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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 ...

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Section: Discussionmentioning

confidence: 99%

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

Traill

Schindler

Coulson

2014

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

107

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“…For each squirrel glider, capture histories were used to estimate the probability of being alive on each day that trapping occurred in any of the seven sample populations. Vague priors were placed on all parameters except annual survival of individuals in control sites, in which case an informative prior based on allometric data (McCarthy et al 2008) and a previous study of squirrel gliders (van der Ree 2000, 2002) were used.…”

Section: Mark-recapture Modelmentioning

confidence: 99%

“…Bayesian informative priors for male and female survival rates were developed using an allometric regression of survival rates on body mass for mammals (McCarthy et al 2008) and a data set from a previous mark-recapture study of squirrel gliders (van der Ree 2000(van der Ree , 2002. These informative priors were used in the model described above, with the data collected in [2005][2006][2007][2008] forming the "data" component of this model.…”

Section: Informative Priorsmentioning

confidence: 99%

“…Body mass was used to predict annual survival of adult male and adult female squirrel gliders based on an allometric model and a worldwide data set of survival rates in mammals (McCarthy et al 2008 …”

Section: Allometric Regressionmentioning

confidence: 99%

“…A number of ecological studies have improved the precision of model estimates by including Bayesian informative priors (e.g., Martin et al 2005, McCarthy and Masters 2005, McCarthy et al 2008). In our study, there was a small but noticeable improvement in precision for estimates of apparent annual survival rates when some prior information was included compared with using vague priors, but there was little or no improvement in the precision of the relative apparent survival rate when informative priors were used.…”

Section: Informative Priorsmentioning

confidence: 99%

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Evidence that a Highway Reduces Apparent Survival Rates of Squirrel Gliders

McCall¹,

McCarthy²,

Ree³

et al. 2010

E&S

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ABSTRACT. Roads and traffic are prominent components of most landscapes throughout the world, and their negative effects on the natural environment can extend for hundreds or thousands of meters beyond the road. These effects include mortality of wildlife due to collisions with vehicles, pollution of soil and air, modification of wildlife behavior in response to noise, creation of barriers to wildlife movement, and establishment of dispersal conduits for some plant and animal species. In southeast Australia, much of the remaining habitat for the squirrel glider, Petaurus norfolcensis, is located in narrow strips of Eucalyptus woodland that is adjacent to roads and streams, as well as in small patches of woodland vegetation that is farther from roads. We evaluated the effect of traffic volume on squirrel gliders by estimating apparent annual survival rates of adults along the Hume Freeway and nearby low-traffic-volume roads. We surveyed populations of squirrel gliders by trapping them over 2.5 years, and combined these data with prior information on apparent survival rates in populations located away from freeways to model the ratio of apparent annual survival rates in both site types. The apparent annual survival rate of adult squirrel gliders living along the Hume Freeway was estimated to be approximately 60% lower than for squirrel gliders living near local roads. The cause of the reduced apparent survival rate may be due to higher rates of mortality and/or higher emigration rates adjacent to the Hume Freeway compared with populations near smaller country roads. Management options for population persistence will be influenced by which of these factors is the primary cause of a reduced apparent survival rate.

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