LTER Network Research Initiative III. Climate Change: Climate Initiative Report

Bruce Hayden and Deb Peters

20 September 2003

56 people in attendance; names, sites, and emails attached below

A. We attempted to address three main questions:

What are the big questions that require multiple sites? These questions should be long term across sites using a consortium of scientists.
What kinds of experiments could be conducted?
What would this multiple site effort look like?

B. Four general issues were discussed in the workshop related to these overall questions:

Current experiments on climate being conducted at LTER sites
Observatory systems that are either ongoing or need to be added related to climate
New experiments that can be conducted across sites to address the big science questions
Limitations to predictability

C. Issues

Current experiments associated with climate being conducted at LTER sites

Hydrologically based experiments to modify rainfall, snow, tides in frequency, distribution, and amount of water (e.g., rainout shelters, vegetation manipulations)

Sites with ongoing exps.: HBR, SEV, PAL, KNZ, VCR, HFR, MCM, BNZ

Sites that would like to add these exps: NTL, GCE, ARC, FCE

“SET” tidal distance observations

Research across climatic gradients, including climate-vegetation gradients

Within LTER sites: NWT, CWT, HBR, AND, BNZ, PAL, NTL

Across LTER sites and continents: SEV, JRN

Soil warming experiments, including open top chambers to modify temperature

Sites with these experiments: KNZ, ARC, NWT, CAP, HFR, PAL, MCM, SGS

Elevated CO₂ experiments

Current sites: HFR, CAP, GCE, CAP, NWT, SGS, PAL, KNZ

Urban areas and interactions with sites

Sites with experiments: CAP, BNZ, NTL, JRN, SBC, SGS, SEV

Modeling climate change effects on ecosystems

Sites with mesoscale models: BNZ, SGS, CAP, LUQ, NTL, JRN, SEV

Some sites also use Global Climate Model (GCM) output

Most sites have hydrological models, and a few have models of groundwater (VCR)

Observatory systems

[Note: these systems need to account for “local” effects on long term instruments]

Many sites have >5 networked met stations so additional met stations may not be critical, except for large sites that have few stations (e.g., SEV).

Need more info on snow and frozen soil (need antecedent site conditions along with snow amount, timing, and distribution)

Need phonological observations as related to climate

Need atmosphere-biosphere interactions and atmospheric fluxes

Need aerosol/aromatic observations

Need remotely sensed images and relationship with energy fluxes

Need to monitor extreme events: need to account for episodic, sequential nature of events plus ecological context of landscape and how the context interacts with the climate in determining ecosystem response

New experiments

Climate variability

Need experiments on site/ecosystem responsiveness to pulses

Need to ask: what are the rules? What will happen in the future?

Measurements needed: 1) key organisms, 2) biodiversity, 3) ecosystem processes (e.g., NPP, water and nutrient cycles), 4) atmospheric chemistry

Where should these experiments be conducted? At ecotones for greatest response

How long should these exps. run? Multiple decades

Retrospective studies in the “near term past” (< 200 yBP)

Detailed ecological information analyses of structure and function are needed to verify DGVM (dynamic global vegetation model) output.

LTER data and analyses can be used to provide hypotheses.

Climate variability and interactions with disturbances, such as fire, hurricanes, and drought

Climate variability and its interactions with invasions/ extinctions, such as insect outbreaks (e.g., woody plant invasion and drought x grazing interactions at JRN)

Also need to account for interactions with atmospheric inputs (NIWOT and fish extinctions due to N inputs; HBR and calcium with trees). Expected to also be important for coastal sites.

Climate variability with human-natural systems

Human adaptation and mitigation important as demands for water increase with increasing population growth in the West despite drought and climate variability. [not just the urban sites but other sites where human populations are having an impact]

Climate variability and landscape change

How do we tease a part changes in climate and changes in landscape structure and dynamics? Models or large scale, long term experiments can be used (JRN is starting these exps. now)

Climate can be a risk or can provide an opportunity.

Context specificity of results.

C₃ and C₄production through time and across space as related to historical climate over the past several centuries (correlation analysis)

Limits to predictability

We need a network of landscape models that work across sites and ecosystems. These models need to be more spatially and temporally resolved than the current biogeographic models, and more robust than the current site-specific models.

We need to know the effects of climate change on the alteration of hydrological cycles.

We need to know the effects of climate change on photosynthesis and respiration, and the relationship to ecosystem services (e.g., water yield, air quality).

We need to know the critical thresholds in climate change and variability that affect ecosystem structure and function.
We need to know how to capture changes in the C₃: C₄ ratio of plants.

We need to know how climate change/variability interacts with species life cycles (seasonality of climate and phenology of species interactions).

We need to know the interactions among species assemblages and climate, and ecosystem lags in responses to climate that are related to species, climate, and soil characteristics.

We need to understand the carbon budget: how can we balance the carbon budget at each site?

We need to understand how landscape structure interacts with climate change and variability.

Education and outreach possibilities

Climate research at LTER sites corresponds to multiple categories of K-12 National Science Education Standards (e.g., earth and space science, life science, science and technology, science in personal and social perspectives). This provides opportunities to use climate research at LTER sites to enhance science teaching and learning at the K-12 level.

Synthetic climate research will provide additional opportunities for involvement by undergraduates, graduate students, and postdocs, thus supporting the future generation of ecologists.

People in attendance