Sensitivity Analysis Using Site-Specific Demographic Parameters to Guide Research and Management of Threatened Eastern Massasaugas

Bradke, Danielle R.; Bailey, Robyn L.; Bartman, Jeffrey; Campa, Henry; Hileman, Eric T.; Krueger, Caleb; Kudla, Nathan; Lee, Yu Man; Thacker, Arin J.; Moore, Jennifer A.

doi:10.1643/ot-18-059

Cited by 4 publications

(2 citation statements)

References 73 publications

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“…Snakes in general have notoriously low encounter rates (Parker & Plummer, 1987; Steen, 2010). This problem is exacerbated for most tropical species, which may contribute to why evidence of transience is lacking (i.e., insufficient statistical power) in most snake studies (Bradke et al, 2018; Cayuela et al, 2019; Lelièvre et al, 2013; Sewell, Baker, & Griffiths, 2015), except in rare instances where transience has been detected and treated as a nuisance parameter to correct for bias in survival estimates (Jones, King, & Sutton, 2017; Koons, Birkhead, Boback, Williams, & Greene, 2009). We similarly used the transient effect to correct bias in survival; however, we also removed the effects of resident survival to estimate the proportion of transients and included supporting evidence to link this population‐level effect to an ontogenetic shift in diet.…”

Section: Discussionmentioning

confidence: 99%

Effects of body size, diet, and transience on the demography of the arboreal boid snake Corallus grenadensis on Carriacou (Grenada Grenadines, West Indies)

Henderson

Hileman

Sajdak³

et al. 2021

Population Ecology

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Remarkably little is known about the demography of snakes in the family Boidae. This lack of information may be attributed, in part, to low population densities on the Neotropical mainland, rendering capture‐recapture methods impractical for many species. Conversely, islands support fewer species but snake densities can be much higher. Corallus grenadensis is an arboreal boid endemic to the Grenada Bank and, relative to mainland boids, can be amazingly abundant. As young, its diet is comprised largely of native Anolis lizards, a ubiquitous and abundant food source; it then undergoes an ontogenetic shift in diet to a less abundant resource, rodents. From 2015 to 2019, we marked 254 C. grenadensis and used capture–recapture models to estimate abundance, capture probabilities, survival, and the proportion of transients. We hypothesized that the transient effect would increase with body size (snout–vent length [SVL]), prompted by their ontogenetic shift in diet. Capture probabilities increased with sampling effort and decreased with increasing SVL. Abundance ranged from 96 to 141 individuals and annual resident survival was 0.71, 95% confidence interval (CI) = 0.54–0.83. The proportion of transients increased with increasing SVL, with the estimate being distinguishable from zero starting at ~810 mm SVL, coinciding with the size at which their dietary shift from ectothermic to endothermic prey begins. Ontogenetic dietary shifts are widespread in snakes and occur in at least 11 of 17 species of West Indian boids. Thus, the prominence of transients in our study may be indicative of its demographic and ecological importance among other snake species.

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Section: Discussionmentioning

confidence: 99%

Effects of body size, diet, and transience on the demography of the arboreal boid snake Corallus grenadensis on Carriacou (Grenada Grenadines, West Indies)

Henderson

Hileman

Sajdak³

et al. 2021

Population Ecology

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“…Methods that allow multiple rates to vary simultaneously, e.g. Latin hypercube sampling (Fordham et al, 2016;Bradke et al, 2018), may be better suited to capture nuances of parameter interactions. However, our approach still provides insight into how the future trajectories would change if the elicited demographic rates are incorrect.…”

Section: Discussionmentioning

confidence: 99%

A demographic projection model to support conservation decision making for an endangered snake with limited monitoring data

Tucker

McGowan

Oliveras

et al. 2020

Animal Conservation

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Conservation planning for rare and threatened species is often made more difficult by a lack of research and monitoring data. In such cases, managers may rely on qualitative assessments of species risk that lack explicit acknowledgement of uncertainty. Snakes are a group of conservation concern that are also notoriously difficult to monitor. Here, we demonstrate a quantitative population projection for a data-deficient species, the Puerto Rican boa (Chilabothrus inornatus) using expert knowledge and published information about species life history and threats to persistence. Using this model, we simulated population dynamics over 30 years under four scenarios of future urbanization and found that there was an increased probability of population decline as urbanization rates increased. We conduct a sensitivity analysis to evaluate the sensitivity of outcomes to model inputs, a practice that may also be useful in recovery planning. The sensitivity analyses also provide insight into how the future trajectories would change if the elicited demographic rates are incorrect. Even when data are sparse, quantitative methods can often be used to produce rigorous and reproducible estimates of future status with quantifiable uncertainty.

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Relative Importance of Vital Rates to Population Dynamics of Wood Ducks

2019

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The wood duck (Aix sponsa) is a common and important cavity-nesting duck in North America; however, we know very little about how changes in vital rates influence This is the author manuscript accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as

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Sensitivity Analysis Using Site-Specific Demographic Parameters to Guide Research and Management of Threatened Eastern Massasaugas

Cited by 4 publications

References 73 publications

Effects of body size, diet, and transience on the demography of the arboreal boid snake Corallus grenadensis on Carriacou (Grenada Grenadines, West Indies)

Effects of body size, diet, and transience on the demography of the arboreal boid snake Corallus grenadensis on Carriacou (Grenada Grenadines, West Indies)

A demographic projection model to support conservation decision making for an endangered snake with limited monitoring data

Relative Importance of Vital Rates to Population Dynamics of Wood Ducks

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