Population viability analysis of plant and animal populations with stochastic integral projection models
Authored by Malo Jaffre, Galliard Jean-Francois Le
Date Published: 2016
DOI: 10.1007/s00442-016-3704-4
Sponsors:
French National Research Agency (ANR)
French National Center for Scientific Research (CNRS)
Platforms:
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Model Documentation:
Other Narrative
Mathematical description
Model Code URLs:
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Abstract
Integral projection models (IPM) make it possible to study populations
structured by continuous traits. Recently, Vindenes et al. (Ecology
92:1146-1156, 2011) proposed an extended IPM to analyse the dynamics of
small populations in stochastic environments, but this model has not yet
been used to conduct population viability analyses. Here, we used the
extended IPM to analyse the stochastic dynamics of IPM of small
size-structured populations in one plant and one animal species (evening
primrose and common lizard) including demographic stochasticity in both
cases and environmental stochasticity in the lizard model. We also
tested the accuracy of a diffusion approximation of the IPM for the two
empirical systems. In both species, the elasticity for lambda was higher
with respect to parameters linked to body growth and size-dependent
reproduction rather than survival. An analytical approach made it
possible to quantify demographic and environmental variance to calculate
the average stochastic growth rate. Demographic variance was further
decomposed to gain insights into the most important size classes and
demographic components. A diffusion approximation provided a remarkable
fit to the stochastic dynamics and cumulative extinction risk, except
for very small populations where stochastic growth rate was biased
upward or downward depending on the model. These results confirm that
the extended IPM provides a powerful tool to assess the conservation
status and compare the stochastic demography of size-structured species, but should be complemented with individual based models to obtain
unbiased estimates for very small populations of conservation concern.
Tags
Evolution
Dynamics
Demography
Extinction
Size
Survival
Age-structured populations
Environmental stochasticity
Flowering
strategies
Cohort variation