Synthesizing information for the environmental sciences
Potential from emerging tools
Jim Clark
Nicholas School of the Environment
Department of Biology
Department of Statistical Science

Example: the climate change puzzle
Uncertain climate predictions
Complicated patterns in ecological data

Models of current climate
Precipitation (control runs)
Convective storms
Multiple moisture sources (Gulf, Atlantic)
Location and strength of:
Bermuda High
Nocturnal jet
Hurricane moisture in summer

Models of future climate
2 x CO2 Precip
Dry winter, summer

Models of future climate
hot

Models of response
SE aridity and savanna expansion

Models of response
Climate change impacts on species
Based on climate envelopes
Correlations with long-term averages
Plants respond to weather
Future climates will be novel
Ignore subgrid processes

Source of immigrants?
Source of immigrants?
Biodiversity responds to spatial heterogeneity
Subgrid processes:
Growth and survival respond to gaps

Seed has limited production and dispersal
Varies by species

What do ÔprocessÕ data say?
Residents vs potential invaders
Could  coastal plain spp invade the Piedmont?
Could Piedmont spp invade the S. Appalachians?
Relative demographic performance of residents vs potential invaders?

Seedling germination
Seedling growth rates
Seedling survival
Process data            climate correlations
 No advantage to potential invaders for any demographic rate in any local habitat
Complex
WhatÕs missing?

Challenges
How will each species respond to changing climate, in the context of environmental variation?
Differential responses with size and age
Causal factors multiscale, interact
Causal factors and responses partially observed.

Outline
Prediction framework
Assimilating models and data

Outline
Prediction framework
Assimilating models and data

Prediction framework
X,y data
M model
qM parameters
XÕ scenario
yÕ prediction

Outline
Prediction framework
Assimilating models and data

Our approach
Long-term demographic monitoring (1991-)
Experiments
Individuals to small plots to landscapes
Intervention designs
Manipulate environment
Introduce potential immigrants
Detailed environmental data
Hierarchical modeling to
Integrate all sources of information
Accommodate the unknowns

Long term, heterogeneous data
Mapped stands
All life history stages
Seed rain
Seed banks
Seedlings
Saplings
Mature trees
Interventions
Canopy gaps
Nutrient additions
Herbivore exclosures
Fire
Environmental monitoring
Canopy photos
Soil moisture
Temperature
Wireless sensor networks
Remote sensing

Heterogeneous data
Simulator for analysis/prediction
Missing the connections
Hierarchical Bayes model
Light availability: ground to remote data
Ground measurements
Remote sensing
Exposure to sky

Solar geometry models
Estimates combine three data types
What makes this possible?
Inference
State space model: Fixed and random individual effects

Inference
Maturation status

Inference
Seed prediction from estimated fecundity

Inference
Seed prediction from estimated fecundity

Estimates of hidden states
Sources of variability/uncertainty in fecundity
Inference
Semiparametric mortality

Mortality risk with size, growth rate
Allocation: among individuals
Many estimates
27 parameters for growth, fecundity, and associated process and observation errors
T fixed year effects
40 mortality risk estimates (34 growth rate classes, 6 diameter classes)
2n random effects (growth and fecundity)
5nT latent states (canopy area, diameter, fecundity, maturation status, mortality risk)
n > 103 trees
T = 16 years (1992 – 2007)

Slide 45
Slide 46
Prediction framework
X,y data
M model
qM parameters
XÕ scenario
yÕ prediction

The implications: Scalable Landscape Inference & Prediction (SLIP)
Prediction that incorporates sources and scales for knowns and unknowns
How to be efficient?

SLIP Light Model
Light computation explicit each m2
Individual trees
Graphics hardware based algorithm

Detail where it matters
SLIP Dispersal Algorithm
Forward simulation:
individuals respond to landscape influences
Competitive exclusion
with random effects
The advantages of multilevel modeling
Fully exploit data through coherent assimilation
Synthesis of all information
Predictions follow directly from estimates

The challenges
Modeling: When is complexity warranted?
Abundant, heterogeneous data
Products important
Repeated application, e.g, spp, sites, intervals
Ex: software for broad use, dissemination; NWP
Doing the computation
Efficient algorithms, data structures

Collaborators
Lab participants:
Brian Beckage (Univ Vermont)
Jim Clark
Mike Dietze
Janneke HilleRisLambers (Univ Washington)
Ines Ibanez
Shannon LaDeau (Smithsonian Inst)
Allen McBride
Jason McLachlan (Notre Dame Univ)
Jackie Mohan (Harvard Univ)
Mike Wolosin
Pete Wykoff (Univ Minnesota)