Residence time: An overlooked constraint on community assembly
and structure Ken Locey Jay Lennon
Slide 2
Shifting Dimensions: Temporal Ecology for the Next 100 Years
and Beyond From the ESA website: A field of temporal ecology has
yet to emerge. divergent vocabularies producing different terms for
similar concepts a compelling need to develop temporal ecology.
unique aspects of time that can underpin the framework for temporal
ecology.
Slide 3
Spatial Ecology is highly-developed compared to Temporal
Ecology SpatialTemporal Pattern: Species-area Distance-Decay
Species-time Process: Dispersal Growth, Foraging Theory:
Biogeography Metacommunity Life History Optimal foraging
Dimensions: 3 1 Constraint: Distance, Area, Volume Time Ecological
unit: Geographic range ? (sub)Discipline: Biogeography, Spatial
Ecology, landscape ecology Temporal Ecology (lacking
foundations)
Slide 4
Accumulation of species Species-time relationshipSpecies-are
relationship White et al. (2010). Understanding species richness
patterns is a fundamental problem in ecology. The major focus as
been on spatial gradients, with a smaller emphasis on temporal
dynamics.
Slide 5
Dispersal Almost always referred to as dispersal across space
Often modeled as instantaneous individual movement Dispersal
limitation and barriers are usually spatial
Slide 6
Species geographic range Species-time relationshipSpecies-are
relationship White et al. (2010). Understanding species richness
patterns is a fundamental problem in ecology. The major focus as
been on spatial gradients, with a smaller emphasis on temporal
dynamics.
Slide 7
Physical ecosystem constraints Volume Area Time Flow
Slide 8
Chemostat Theory: Predicting resource and time limited
growth
Slide 9
Average time a particle spends in the system Residence time ( )
Dilution rate ( ) portion of the system replaced per unit time
Slide 10
Residence time ( ): primary physical constraint in chemostat
theory
Slide 11
Residence time ( ) An important constraint in bioreactors
Slide 12
Residence time ( ) Important in many systems under volumetric
flow http://www.epa.gov/gmpo/images/targeted- areas-neps-sm.jpg
http://upload.wikimedia.org/wikipedia/commons/
4/44/Hemimysis_anomala_GLERL_2.jpg
Slide 13
Residence time ( ) *Primary predictions = mean cell residence
time = specific growth rate *Fine print: For a system at
equilibrium. Includes assumptions that are simplifying for anything
but ideal chemostats.
Slide 14
Questions How should the predictions fail as the assumptions
are violated? In absence of failure, what else can we predict from
and ?
Slide 15
HydroBIDE Chemostat Theory + Individual-based Modeling
Slide 16
Slide 17
Slide 18
Slide 19
Slide 20
Tighten the bolts: Models act like ideal chemostats Includes:
maintenance cost and species differences Mean cell residence time
Residence time (V/F)
Slide 21
Loosening the bolts: Immigration dampens growth rate? Includes:
maintenance cost and species differences & immigration
Residence time (V/F)
Slide 22
How should influence abundance and diversity? Residence time
(V/F)
Slide 23
How should influence abundance and diversity? Including and
excluding immigration produce the same general result
Slide 24
Residence time ( in general theory A fun paradox matters in
ecosystems is primary to chemostat theory Chemostat theory modified
for many specific systems But, basic chemostat theory not seen as a
simplifying theory for biodiversity Yet, many general theories are
oversimplified
