The last litter bag collected at HJ Andrews was tag number 1

Long-Term Intersite Decomposition Experiment Team

(LIDET) Project

Synthesis Approach

Pre-planned experiment Team-designed Centrally coordinated Standardized methods Predetermined spatial and temporal limits

LIDET EstablishmentNSF Workshop

Woods Hole Marine Biological Laboratory, May 1989

Recognition of greater value in joint project with common measurements

Realization that not all decomposition controlling factors can be studied

Discussion of investigator-related issues Clearly define role of project participants Develop equitable strategy for publication credit Balance standardization and central control against needs of

individual sites

Study Description

Test the effect of substrate quality and macroclimate on long-term decomposition and nutrient dynamics

10 year experiment 28 sites (17 LTER sites) Long-term, broad-scale, multi-site, multi-

investigator experiment to provide regional and global perspective

•Wide array of ecosystem types

•Annual precipitation

230-4000 mm per year

•Mean annual air temperature

–7 to 26 degrees C

Distribution of LIDET Sites

Distribution of sites across climatic gradient

Formation of LIDET Team

Field Collaborators (1 per site) Manages experiment at local level Provides background information

Central Analysis Group (central site) Coordinates chemical analysis and data processing Manages long-term data and sample archive Conducts preliminary data analysis

Modelers (CENTURY, GEM, GENDEC, DODMOD) Examine process models Test to determine most general structures and assumptions

Methodology Generally accepted methods were easy to standardize -

Litter bags and dowels Initially collect 9 standard litters and 28 wildcard litters

3 Fine roots - (graminoid, hardwood, conifer) 6 Leaf litter - (lignin/nitrogen ratio 6 to 43) 1 Wildcard (leaf litter) from each site 1 Wooden dowel (above/below ground decomposition)

Centrally prepare and distribute all materials to each site Collect samples annually for 10 years

4 reps for each species, site, time

Centrally analyze for chemical composition Near-infrared reflectance (NIR) spectroscopy (Total nitrogen, lignin, cellulose)

Continental Level

Site Level

Replicate Level

Geographical Distribution of

Sampling Scheme

Litterbags are distributed

throughout an array of ecosystems

Wooden Dowels measure both above- and belowground decomposition

Initial Litter CollectionStandardLitters(9 sites)

“Wildcard”Litters

(28 sites)

“Litterbag Central”

Litterbagsconstructed

Data entry&

Chemicalanalysis

Datamanagement

LitterbagsInstalled

(once)

LitterCollected(10 times)

DataUpdate

(10 times)

Field Experiments at 28 Sites

Information and Materials Flow in LIDET

Litterbags at various stages of decomposition

Shared Data and Credit Central site annually provides data to each site Site has one-year for site-specific publishing After one year, site data is available for intersite

synthesis under joint LIDET authorship or modeling Only published data is available to the public

(Special requests have been honored) In the end, all data will be public, and the database

will be maintained in a long-term data repository at the OSU Forest Science Data Bank (FSDB)

Data Processing and Information Management

PI initially designed data structures Data and metadata structures conformed to FSDB protocols ASCII data and SAS processing routines

16,000+ samples provided logistical challenge Relational database interface developed

Generates site forms annually indicating litter bags to remove Provides data entry screens Merges analytical data into database Prints reports and sample labels Conducts preliminary calculations of decay rate and % mass

Approaches to QA/QC

Central preparation of materials Initial estimation of oven-dried litter weight

Comprehensive instructions sent originally Instructions resent annually

Data sent annually for site to review and keep Dowel provides link to other decomposition studies

Lab and Data QA/QC Laboratory

Initial evaluation and comparison of laboratories Consistent laboratory and methods Wet chemistry calibration of NIR analyses Spot checking of site weight measurements

Data Data codes were provided to document questionable data Percent remaining mass data plotted to track outliers Catalog of samples tracked in relational database Visual inspection

Obstacles to Intersite Synthesis Change is constant – “Assume nothing!”

Over 10 years personnel changes, instructions lost, maps lost

Study sites not protected Fires, forestry projects, accidents

Logistical problems Established infrastructure at sites

17 of 28 sites being LTER sites minimized cost Communication

Development of electronic email network was great improvement

Obstacles to Preparing LIDET Data

Data processing and analysis of 16,000+ samples pose logistical problems

Sites do not always follow instructions Site information is generally not available Climate data requests were frequently ignored Feedback from site reviews of annual data was

lacking or incomplete – “it’s wrong”

Current LIDET Status

2001 is final year of litter bag removal Total experiment duration will be 13-14 years

(1 year setup and 2-3 years data cleanup and analysis)

25 of 28 sites will complete the experiment Resource largely unpublished NCEAS-like workshop under consideration

(possible Springer-Verlag book on decomposition)

Intersite Project Success

Interesting ideas or hypotheses are essential to attract investigators

Increased funding to conduct many measurements needed

Strong communication among scientists and coordination of activities are essential to produce comprehensive tests of hypotheses

Benefits of Approach Places individual site results in a larger context Allows access to novel analytic methods (NIR) Greater sense of participation on global change

research Advantages of a team-designed, simultaneously-

conducted experiment vs. “post”-harmonization approachAvoids limitations due to disparities in geographic

distribution, study duration, and methodologies“Synthesis before, not after, the fact!”

Mark Harmonization in action

Special thanks to Mark Harmon and Becky FasthAdditional thanks to Suzanne Remillard and Jay Sexton

Citation: Long-Term Intersite Decomposition Experiment Team (LIDET). 1995. Meeting the challenge of long-term, broad-scale ecological experiments. Seattle, WA: LTER Network Office; Publication No. 19. 23 p.

LTER- and NSF-supported through Ecosystem Studies Grants