A functional trait approach to identifying life history patterns in stochastic environments

Isabel M. Smallegange, Matty P. Berg

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Temporal variation in demographic processes can greatly impact population dynamics. Perturbations of statistical coefficients that describe demographic rates within matrix models have, for example, revealed that stochastic population growth rates (log(λs)) of fast life histories are more sensitive to temporal autocorrelation of environmental conditions than those of slow life histories. Yet, we know little about the mechanisms that drive such patterns. Here, we used a mechanistic, functional trait approach to examine the functional pathways by which a typical fast life history species, the macrodetrivore Orchestia gammarellus, and a typical slow life history species, the reef manta ray Manta alfredi, differ in their sensitivity to environmental autocorrelation if (a) growth and reproduction are described mechanistically by functional traits that adhere to the principle of energy conservation, and if (b) demographic variation is determined by temporal autocorrelation in food conditions. Opposite to previous findings, we found that O. gammarellus log(λs) was most sensitive to the frequency of good food conditions, likely because reproduction traits, which directly impact population growth, were most influential to log(λs). Manta alfredi log(λs) was instead most sensitive to temporal autocorrelation, likely because growth parameters, which impact population growth indirectly, were most influential to log(λs). This differential sensitivity to functional traits likely also explains why we found that O. gammarellus mean body size decreased (due to increased reproduction) but M. alfredi mean body size increased (due to increased individual growth) as food conditions became more favorable. Increasing demographic stochasticity under constant food conditions decreased O. gammarellus mean body size and increased log(λs) due to increased reproduction, whereas M. alfredi mean body and log(λs) decreased, likely due to decreased individual growth. Our findings signify the importance of integrating functional traits into demographic models as this provides mechanistic understanding of how environmental and demographic stochasticity affects population dynamics in stochastic environments.

Original languageEnglish
Pages (from-to)9350-9361
Number of pages12
JournalEcology and Evolution
Volume9
Issue number16
Early online date31 Jul 2019
DOIs
Publication statusPublished - Aug 2019

Fingerprint

autocorrelation
life history
demographic statistics
population growth
body size
food
stochasticity
population dynamics
energy conservation
temporal variation
reef
environmental conditions
perturbation
matrix
reefs
environmental factors
Manta

Keywords

  • body size
  • dynamic energy budget
  • ecosystem engineer
  • integral projection model
  • noise color
  • performance trait
  • salt marsh
  • stochastic demography
  • Talitridae

Cite this

@article{38c3e5af1d53400c97128c7c8756d880,
title = "A functional trait approach to identifying life history patterns in stochastic environments",
abstract = "Temporal variation in demographic processes can greatly impact population dynamics. Perturbations of statistical coefficients that describe demographic rates within matrix models have, for example, revealed that stochastic population growth rates (log(λs)) of fast life histories are more sensitive to temporal autocorrelation of environmental conditions than those of slow life histories. Yet, we know little about the mechanisms that drive such patterns. Here, we used a mechanistic, functional trait approach to examine the functional pathways by which a typical fast life history species, the macrodetrivore Orchestia gammarellus, and a typical slow life history species, the reef manta ray Manta alfredi, differ in their sensitivity to environmental autocorrelation if (a) growth and reproduction are described mechanistically by functional traits that adhere to the principle of energy conservation, and if (b) demographic variation is determined by temporal autocorrelation in food conditions. Opposite to previous findings, we found that O. gammarellus log(λs) was most sensitive to the frequency of good food conditions, likely because reproduction traits, which directly impact population growth, were most influential to log(λs). Manta alfredi log(λs) was instead most sensitive to temporal autocorrelation, likely because growth parameters, which impact population growth indirectly, were most influential to log(λs). This differential sensitivity to functional traits likely also explains why we found that O. gammarellus mean body size decreased (due to increased reproduction) but M. alfredi mean body size increased (due to increased individual growth) as food conditions became more favorable. Increasing demographic stochasticity under constant food conditions decreased O. gammarellus mean body size and increased log(λs) due to increased reproduction, whereas M. alfredi mean body and log(λs) decreased, likely due to decreased individual growth. Our findings signify the importance of integrating functional traits into demographic models as this provides mechanistic understanding of how environmental and demographic stochasticity affects population dynamics in stochastic environments.",
keywords = "body size, dynamic energy budget, ecosystem engineer, integral projection model, noise color, performance trait, salt marsh, stochastic demography, Talitridae",
author = "Smallegange, {Isabel M.} and Berg, {Matty P.}",
year = "2019",
month = "8",
doi = "10.1002/ece3.5485",
language = "English",
volume = "9",
pages = "9350--9361",
journal = "Ecology and Evolution",
issn = "2045-7758",
publisher = "John Wiley and Sons Ltd",
number = "16",

}

A functional trait approach to identifying life history patterns in stochastic environments. / Smallegange, Isabel M.; Berg, Matty P.

In: Ecology and Evolution, Vol. 9, No. 16, 08.2019, p. 9350-9361.

Research output: Contribution to JournalArticleAcademicpeer-review

TY - JOUR

T1 - A functional trait approach to identifying life history patterns in stochastic environments

AU - Smallegange, Isabel M.

AU - Berg, Matty P.

PY - 2019/8

Y1 - 2019/8

N2 - Temporal variation in demographic processes can greatly impact population dynamics. Perturbations of statistical coefficients that describe demographic rates within matrix models have, for example, revealed that stochastic population growth rates (log(λs)) of fast life histories are more sensitive to temporal autocorrelation of environmental conditions than those of slow life histories. Yet, we know little about the mechanisms that drive such patterns. Here, we used a mechanistic, functional trait approach to examine the functional pathways by which a typical fast life history species, the macrodetrivore Orchestia gammarellus, and a typical slow life history species, the reef manta ray Manta alfredi, differ in their sensitivity to environmental autocorrelation if (a) growth and reproduction are described mechanistically by functional traits that adhere to the principle of energy conservation, and if (b) demographic variation is determined by temporal autocorrelation in food conditions. Opposite to previous findings, we found that O. gammarellus log(λs) was most sensitive to the frequency of good food conditions, likely because reproduction traits, which directly impact population growth, were most influential to log(λs). Manta alfredi log(λs) was instead most sensitive to temporal autocorrelation, likely because growth parameters, which impact population growth indirectly, were most influential to log(λs). This differential sensitivity to functional traits likely also explains why we found that O. gammarellus mean body size decreased (due to increased reproduction) but M. alfredi mean body size increased (due to increased individual growth) as food conditions became more favorable. Increasing demographic stochasticity under constant food conditions decreased O. gammarellus mean body size and increased log(λs) due to increased reproduction, whereas M. alfredi mean body and log(λs) decreased, likely due to decreased individual growth. Our findings signify the importance of integrating functional traits into demographic models as this provides mechanistic understanding of how environmental and demographic stochasticity affects population dynamics in stochastic environments.

AB - Temporal variation in demographic processes can greatly impact population dynamics. Perturbations of statistical coefficients that describe demographic rates within matrix models have, for example, revealed that stochastic population growth rates (log(λs)) of fast life histories are more sensitive to temporal autocorrelation of environmental conditions than those of slow life histories. Yet, we know little about the mechanisms that drive such patterns. Here, we used a mechanistic, functional trait approach to examine the functional pathways by which a typical fast life history species, the macrodetrivore Orchestia gammarellus, and a typical slow life history species, the reef manta ray Manta alfredi, differ in their sensitivity to environmental autocorrelation if (a) growth and reproduction are described mechanistically by functional traits that adhere to the principle of energy conservation, and if (b) demographic variation is determined by temporal autocorrelation in food conditions. Opposite to previous findings, we found that O. gammarellus log(λs) was most sensitive to the frequency of good food conditions, likely because reproduction traits, which directly impact population growth, were most influential to log(λs). Manta alfredi log(λs) was instead most sensitive to temporal autocorrelation, likely because growth parameters, which impact population growth indirectly, were most influential to log(λs). This differential sensitivity to functional traits likely also explains why we found that O. gammarellus mean body size decreased (due to increased reproduction) but M. alfredi mean body size increased (due to increased individual growth) as food conditions became more favorable. Increasing demographic stochasticity under constant food conditions decreased O. gammarellus mean body size and increased log(λs) due to increased reproduction, whereas M. alfredi mean body and log(λs) decreased, likely due to decreased individual growth. Our findings signify the importance of integrating functional traits into demographic models as this provides mechanistic understanding of how environmental and demographic stochasticity affects population dynamics in stochastic environments.

KW - body size

KW - dynamic energy budget

KW - ecosystem engineer

KW - integral projection model

KW - noise color

KW - performance trait

KW - salt marsh

KW - stochastic demography

KW - Talitridae

UR - http://www.scopus.com/inward/record.url?scp=85070969362&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85070969362&partnerID=8YFLogxK

U2 - 10.1002/ece3.5485

DO - 10.1002/ece3.5485

M3 - Article

VL - 9

SP - 9350

EP - 9361

JO - Ecology and Evolution

JF - Ecology and Evolution

SN - 2045-7758

IS - 16

ER -