Population dynamics with multiple limiting
nutrients: Life history mediated effects
Romain Richard
André de Roos
From individual development to population
dynamics
Development
Physiology
Ingestion
Maintenance
Maturation
Life history
& Co
Growth
Fecundity
Mortality
Feeding
Allocation

Being fed upon
Development is a major determinant
of population dynamics
Population /
community
processes
Dynamical effects of development

Makes competition between individual
asymmetric: Individuals are not equally
good at producing biomass

Population cycles
Alternative dynamical attractors
Coexistence
Biomass overcompensation



◦ Catastrophic collapses
◦ Facilitation
◦ Allee effects
Total
Juveniles
Adults
Ecological stoichiometry
Individual experiencing different environment may be limited by
different currency: energy vs mineral limitation
 Focus on environmental and inter-specific variation
 Intra-specific variation due to ontogenetic development

Mechanisms likely to induce changes in the
limiting nutrient through development
Changes at maturation
 Allometric scaling of body composition
 Changes due to ontogenetic diet-shift / metamorphosis
 Size-specific changes in physiological rates (ingestion,
maintenance, maturation…)

How do multiple nutrient limitations affect
individual life histories and what are the
implications for ecological dynamics?
Individual model
Assimilation
Overhead cost
of growth
Growth
Biomass
Maintenance
Reproduction


Carbon is for structural and energetic purposes
Phosphorus is for structural purpose only
Differences in assimilation efficiency
 Differences in specific maintenance rate
 Differences in overhead costs

Overhead cost of
reproduction (includes
provisioning of nutrients
for embryogenesis)
P-rich food
(=> Carbon
limitation)
P-poor food
(=> Phosphorus
limitation)
TER is size-dependent
P-poor
food
TER = critical C:P ratio in the food at which individual
switches from C- to P-limitation
P-rich
food

Phosphorus-limitation
Carbon-limitation
(some) Population consequences
Population extinction with resource enrichment (dilution
effect)
 Alternative stable states: [low food density, high food
quality] vs [high food density, low food quality]
 Dampening / stabilization of population cycles

Biomass overcompensation
Total
Juveniles
Adults
Decrease in phosphorus
concentration = decrease in adult
performance (but not juveniles)
Decrease in population
abundance
Phosphorus
limitation
Carbon limitation
Increase in food density
(Much) increase in both juvenile
performance
More transition of biomass to
adult stages
Increase in adult biomass
Conclusions
Numerous potential implications of biomass
overcompensation
 Interactions between stoichiometric- and sizedependent effects
 Can reverse the scaling of competition predicted by
allometric scaling of ingestion and maintenance

(Personn and de Roos 2013)