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White Lab ::
Research Areas
|
 Marine
metapopulation dynamics
Most
of my current work centers on modeling
the dynamics of marine
metapopulations. Such models are
essential in order to predict the
large-scale, long-term consequences of
empirical observations and to generate
new hypotheses that can be tested by
directed fieldwork. Much of this
research deals with the design and
placement of marine protected areas -
zones in which harvest is prohibited or
severely reduced. My work in this
area involves many collaborators and
has taken several directions:
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•
Marine Protected Area (MPA)
design: strategic models
Most "rules
of thumb" for MPA design (i.e.,
guidelines for how big, how many,
and where they should be) have
their roots in relatively simple
strategic models of idealized,
generic coastlines. My work
in this area has built on previous
efforts to include spatial
heterogeneties in larval dispersal
(e.g., retention zones) and
uncertainty in fishery management
outside MPA boundaries.
Work on this topic is ongoing;
currently I am investigating how
MPA design should anticipate
spatially autocorrelated
environmental disturbances and how
adaptive management should be
applied to the short-term response
of MPAs to protection. This
research is primarily in
collaboration with Loo
Botsford, Alan
Hastings, John
Largier, Marissa
Baskett, and Liz Moffitt;
funded by NSF, Resource Legacy
Fund Foundation, and California
SeaGrant.
Publications
Moffitt EA, White JW, Botsford
LW. Results of monitoring
marine protected areas depend on
metrics and scales. In
review, Marine
Ecology Progress Series
White
JW, Botsford LW, Hastings A,
Baskett ML, Kaplan DM, Barnett
LAK. 2013. Transient
responses of fished populations
to marine reserve establishment.
In press, Conservation
Letters
Moffitt
EA, White JW,
Botsford LW. 2011.
The
utility
and
limitations
of
size and spacing guidelines for
designing marine protected area
networks. Biological
Conservation
144: 306-318
White
JW,
Rogers-Bennett L. 2010.
Incorporating physical
oceanographic proxies of
recruitment into population
models to improve fishery and
marine protected area
management. CalCOFI
Reports
51: 128-149
White
JW,
Botsford
LW, Hastings A, and Largier
JL. 2010.
Population
persistence
in
marine
reserve
networks:
incorporating
spatial
heterogeneities
in
larval
dispersal.
Marine Ecology
Progress Series 398:
49-67
Botsford
LW,
White
JW,
Coffroth
M-A,
Jones
GP, Paris C, Planes S, Shearer
TL, and Thorrold S. 2009.
Connectivity and resilience of
coral reef metapopulations in
MPAs: matching empirical efforts
to predictive needs.
Coral Reefs 28:
327-337
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•
Marine Protected Area (MPA)
design: tactical models
In specific
management situations, it is
necessary to tailor generic
population models to specific
locations and species in order to
advise the decisions of
policymakers. Along with
many colleagues, I have developed
bioeconomic population models used
in the evaluation of MPAs proposed
for coastal California as part of
the Marine
Life Protection Act Initiative.
These models have been used in the
North Central and South Coasts,
and are currently being developed
for the North Coast, where I am a
member of the Science
Advisory Team. In
collaboration with Loo
Botsford, David Kaplan, Doug
Fischer, Liz Moffitt, Chris
Costello, and Andrew
Rassweiler; funded by the
Resource Legacy Fund
Foundation. Although work
for the MLPA in California is
nearly finished, I am currently
developing similar models for
other coastal areas, such as the
Galapagos Islands.
Publications
White
JW, Scholz AJ, Rassweiler A,
Steinback C, Botsford LW,
Kruse S, Costello C, Mitarai
S, Siegel D, Drake PT, Edwards
CA. 2013. A
comparison of approaches used
for economic analysis in marine
protected area network planning
in California. Ocean
and Coastal Management 73:
77-89
White JW,
Botsford
LW,
Baskett
ML,
Barnett
LAK,
Barr
RJ,
Hastings
A.
2011. Linking models and
monitoring data for assessing
performance of no-take marine
reserves. Frontiers
in Ecology and the Environment
9: 390-399
Fischer
DT, White JW,
Botsford LW, Largier JL,
Kaplan DM. 2011.
A GIS-based tool for
representing larval dispersal
for marine reserve
selection. The
Professional Geographer 63:
489-513
White
JW,
Botsford
LW,
Moffitt
EA,
and
Fischer DT. 2010.
Decision analysis for
designing marine protected areas
for multiple species with
uncertain fishery status.
Ecological
Applications
20: 1523-1541
White
JW.
2010.
Adapting the steepness
parameter from stock-recruit
curves for use in spatially
explicit models. Fisheries
Research 102: 330-334
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• Reef
fish metacommunity dynamics
Nearly
all reef fishes have a
planktonic larvae that can spend
weeks to months in the pelagic
zone, potentially dispersing
long distances before settling
back into adult habitat.
The apparent unpredictability of
larval supply has frustrated
efforts to fully understand
marine population dynamics.
However, in some cases
observations and models of
nearshore oceanography can
generate reliable predictions of
dispersal patterns. For
example, long-term
observations at the
Caribbean island of St.
Croix
conducted in collaboration with
colleagues in Bob Warner's lab
at UCSB provide evidence for a
consistent, long term pattern of
larval recruitment of bluehead
wrasse (a common reef
planktivore), apparently driven
by local oceanography.
Additionally, the same
oceanographic factors appear to
drive patterns of recruitment of
coney grouper (a wrasse
predator) and production of
nearshore copepods (wrasse prey)
around the island.
I
have explored the consequences
of these patterns for the
planktivore (wrasse)
metapopulation using a series of
simple analytical and simulation
models. Ongoing
modeling work in collaboration
with Jameal Samhouri centers on
the ecological consequences of
oceanographic forcing across
three trophic levels: spatial
coupling of zooplankton
productivity (generally high in
oceanographic retention zones)
and the larval delivery of reef
planktivores and their predators
(also high in retention
zones). We have used this
model to generate a series of
predictions about larval
production and source-sink
dynamics in reef metacommunities
that we plan to test in the
field in the Florida Keys (and
possibly other locations,
depending on funding) beginning
in 2011.
Publications
White JW, Samhouri
JF. 2011. Oceanographic
coupling across multiple trophic
levels shapes source-sink
dynamics in marine
metacommunities. Oikos
120: 1151-1164
White
JW.
2008. The correlated
settlement effect: spatially
coupled larval supply of marine
predators and their prey alters
the predictions of
metapopulation models. The
American
Naturalist 171:
E179-E194
White
JW. 2007. Spatially
correlated recruitment of a
marine predator and its prey
shapes the large-scale pattern
of prey mortality. Ecology
Letters 10: 1054-1065
Hamilton
SL,
White
JW,
Caselle
JE,
Swearer
SE,
and Warner RR. 2006.
Consistent long-term spatial
gradients of replenishment for
an island population of a coral
reef fish. Marine
Ecology Progress Series
306: 247-256
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Behavior and ecology of reef fishes
across multiple spatial scales
A fundamental goal
of ecology is to understand how
individual-level interactions and
behaviors "scale up" to drive population
dynamics. Reef fishes are an
excellent study system for this topic
because adults and juveniles tend to lead
relatively sedentary lives (making it easy
to monitor populations over time and do
fieldwork at reasonable spatial scales)
and live in clear, coastal waters (making
it easy to count fish and study their
behavior). My work in this area has
mostly been done on bluehead wrasse (Thalassoma
bifasciatum) in St. Croix, US
Virgin Islands, but I am currently
transitioning to work at the UNCW/NOAA lab
in the Florida Keys.
Costs
and benefits of aggregation
Coral reef fishes have proven to be
fertile ground for studies on
density-dependent population
regulation. A host of elegant
studies have demonstrated that soon after
larval fish settle onto the reef and
metamorphose into juveniles, they suffer
heavy density-dependent predation.
Often this is because they are competing
for a limited amount of enemy-free shelter
space. All else being equal, this
phenomenon should select for an aversion
to aggregation. On the other hand,
decades of behavioral research suggest
that fish aggregate into shoals to take
advantage of safety-in-numbers. So
is aggregation advantageous or not?
I addressed this question in my
dissertation research using the bluehead
wrasse, a small Caribbean reef fish.
In this species it appears that small
groups of fish experience safety in
numbers (per capita mortality decreases
with group size), although group members
also compete for planktonic copepod prey,
and this food competition probably limits
group size. However, when wrasse
population density and mortality are
measured at the spatial scale of entire
reef, a different pattern emerges: per
capita mortality actually increases with
density. This may occur
because predatory fishes make foraging
decisions at a spatial scale much larger
than an individual wrasse shoal.
These results seem to resolve the apparent
conflict between the predictions of
population ecology and behavioral
ecology. They have also led to the
development of (1) a conceptual model
describing the relationship between
habitat configuration and the spatial
scale of predator decisionmaking and (2) a
formal mathematical model describing the
interaction of opposing processes at
different scales (e.g., small-scale safety
in numbers vs. large-scale direct density
dependence) on the stability of prey
population dynamics. I am currently
developing field experiments to test these
predictions.
Spatial
scales of predator decisionmaking
Analysis of spatial patterns of
density-dependent mortality in small coral
reef fishes suggests that a key factor
affecting mortality rates could be the
spatial scale at which predators make
foraging decisions. That is, how do
predators decide what is a "patch" of
prey, and how does the size of that patch
affect their foraging decisions?
Research on this topic is currently in the
planning stage, but will involve a
combination of field and lab
investigations.
Publications
Hunsicker
ME, Ciannelli L, Bailey KM, Buckel JA, White
JW, Link JS, Essington TE, Anderson
TW, Brodeur RD, Chan KS, Chen K,
Englund G, Frank KT, Frietas V,
Gaichas S, Hixon MA, Hurst T, Johnson
DW, Kitchell JF, Reese D, Rose GA,
Sjodin H, Sydeman WJ, van der Veer H,
Vollset K, Zador S. 2011.
Functional responses and scaling
in marine predator-prey interactions:
contemporary issues and emerging
concepts. Ecology Letters
14:
1288-1299
White
JW.
2011.
Can inverse density
dependence at small spatial scales
produce dynamic instability in animal
populations? Theoretical Ecology
4: 357-370
White JW, Samhouri JF, Stier
AC, Wormald CL, Hamilton SL, Sandin
SA. 2010. Synthesizing
mechanisms of density dependence in reef
fishes: behavior, habitat configuration,
and observation scale. Ecology 91:
1949-1961
White
JW
and Caselle JE. 2008.
Scale-dependent changes in the
importance of larval supply and habitat
availability to abundance of a temperate
reef fish. Ecology 89: 1323-1333
White JW
and Warner RR. 2007. Behavioral
and energetic costs of group membership
in a shoaling reef fish. Oecologia
154: 423:433
White
JW and Warner RR. 2007. Group size
benefits and the spatial scaling of
density dependence in a coral reef
fish. Ecology 88: 3044-3054
|
 Multivariate
statistics for stock discrimination
analysis
Efforts
to understand marine metapopulation
biology are often hampered by the lack of
knowledge about the movement patterns of
pelagic larvae. My collaborators in
Bob Warner's lab at UCSB and elsewhere
have begun using the trace elements
deposited in fish otoliths as a natural
'tag' to track larval movements.
Different water masses, especially those
near terrestrial runoff inputs, tend to
produce distinctive signatures in the
otoliths of fish spawned there. In
theory it is possible to look at the natal
signature in the core of a fish's otolith
and determine where that fish was spawned,
thus cracking open the 'black box' of
larval movement. However, there are
some knotty statistical problems involved
in these efforts, primarily as a result of
the small sample sizes involved and the
impossibility of sampling every possible
larval source. With the help of
several collaborators, I have adapted and
refined existing statistical techniques to
better deal with these issues.
Currently this work is done in
collaboration with Seth Miller and Steven
Morgan at UC Davis, examining patterns of
larval dispersal in intertidal crabs, and
with Scott Hamilton and Bob Warner at
UCSB, examining dispersal in kelp bass and
other nearshore larval fish species.
Publications
Miller
SH, Morgan SG, White JW,
Green PG. Can trace element signatures
in larval soft tissues reveal dispersal
and population connectivity? In review,
Marine
Ecology Progress Series
Miller SH,
Morgan SG, White JW, Green PG.
2013. Interannual variability in
an atlas of trace element signatures for
determining population connectivity. Marine
Ecology Progress Series 474:
179-190
Standish
JD, White JW, and Warner RR. 2011.
The spatial pattern of natal
signatures in the otoliths of juvenile Sebastes
atrovirens along the California
coast. Marine Ecology Progress
Series 437: 279-290
White
JW,
Standish
JD, Thorrold SR, and Warner RR.
2008. Markov chain – Monte
Carlo methods for assignment of natal
origins and mixed-stock analysis using
natural geochemical tags. Ecological
Applications 18:1901-1913
software
White
JW and Ruttenberg BI. 2007.
Discriminant function analysis in marine
ecology: some common oversights and
their solutions. Marine
Ecology Progress Series 329:
301-305
software
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Miscellaneous
ongoing projects
I
am generally interested in the application
of quantitative methods and population
models to questions in population and
community ecology. In that spirit, I
have ongoing (mostly unfunded)
collaborations with researchers in a range
of fields.
• Cyclic
population dynamics of Pacific salmon
stocks
With Loo Botsford, Alan
Hastings, and Matt Holland, UC Davis;
funded by NSF GLOBEC.
A curious and well-known
characteristic of sockeye salmon stocks
in the Fraser River watershed in British
Columbia is a cyclic pattern of spawner
abundance, usually with a strong peak
once every four years.
Understanding the mechanisms that
initiate and sustain these cycles would
be useful to the management of the
sockeye fishery and will be essential to
predicting how these stocks will respond
to large-scale environmental shifts,
including the Pacific Decadal
Oscillation and anthropogenic climate
change. Our group is using a
combination of analytical and simulation
models to explore the sources of
population cycles in sockeye stocks from
the Fraser River and other watersheds
(e.g., Bristol Bay, Alaska).
Publications
Botsford,
LW,
Holland MD, Samhouri JF, White JW,
Hastings A. 2011.
Importance of age structure in models of
the response of upper trophic levels to
fishing and climate change. ICES
Journal of Marine Science 68:
1270-1283
White
JW, Botsford LW, Hastings A,
Holland MD. Stochastic models reveal
conditions for cyclic dominance in
sockeye salmon populations. In review,
Ecological Monographs
• Spatial
variability in recruitment and population
dynamics of oysters
We are using a multi-year
dataset of oyster density in Tomales
Bay, CA, to examine the relative
influence of spatial variability in both
recruitment and mortality on population
dynamics in a tidal estuary.
• Nearshore
oceanography and larval transport
With Kerry Nickols and John
Largier, UC
Davis Bodega Marine Lab.
Emerging evidence suggests
that the region of slow-moving currents
in the extreme nearshore (within ~1-2 km
of the coastline) might be where many
marine larvae spend their entire pelagic
period. Consequently, accounting
for oceanography in this zone may be of
particular importance, yet it is
typically ignored by most large-scale
descriptions of larval transport.
We are using disperal simulations and
population models to explore the
consequences of flow in this region.
Publications
White
JW,
Nickols KJ, Clarke L, Largier JL. 2010. Population
effects of larval entrainment in cooling
water intakes: spatially explicit models
reveal shortcomings of traditional
assessments. Canadian Journal of Fisheries
and Aquatic Sciences 67:
2014-2031
• Improving
field estimation of pelagic larval
mortality
Pelagic
mortality is a major factor affecting
the dispersal of planktonic larvae of
benthic organisms. Unfortunately,
existing mortality estimation methods
rely on large-scale sampling regimes
which are difficult to implement for
nearshore samples of meroplankton.
We have developed an estimation method
that builds on existing vertical life
table methods but accounts for the
patchy spatial distribution of plankton
to produce reliable mortality estimates
using data collected at small spatial
scales.
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Miscellaneous
completed projects
• Population
dynamics of invasive species in fouling
communities
Cascade has conducted a series
of experiments to indentify interaction
strengths among invasive and native
species in fouling communities in San
Francisco Bay. Together we are
using multispecies population models to
identify stable community trajectories
and examine how they might be altered by
climate change.
Publications
Sorte CJB, JW
White. Competitive and demographic
leverage points of community shifts
under climate change. In review, Proceedings
of the Royal Society (B)
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All
text and images (except UNCW logo) copyright 2010 JW
White
Last
modified 24 July 2012
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