Data Set Citation:
When using this data, please cite the data package:
NCEAS 9520: Utilizing meta-analysis and structural equation modeling to disentangle the influences of functional traits and environmental context , National Center for Ecological Analysis and Synthesis , and Cleland E.
Synthesis of nitrogen fertilization experiments in North America - plant species relative abundance
knb.192.5 (http://knb.ecoinformatics.org/knb/metacat/knb.192.5/nceas)
General Information:
Title:Synthesis of nitrogen fertilization experiments in North America - plant species relative abundance
Identifier:knb.192
Abstract:
Nitrogen (N) is a limiting nutrient to plant growth in many ecosystems, and human-caused N enrichment has the potential to fundamentally alter the structure and functioning of plant communities. Nutrient limitation of primary production has been of interest to ecologists for many years, as a result there are many fertilization experiments in diverse community types. A group of Long Term Ecological Research (LTER) network researchers founded PDT-Net (Productivity, Diversity &raits Network), to synthesize datasets from fertilization experiments in herbaceous communities across North America. Although responses to N addition were highly variable, several clear patterns emerged. We found that N addition increased productivity, reduced plant species diversity, and that plant species with particular functional traits (e.g. N-fixation ability, native and annual species) declined with fertilization, while others increased in dominance. Differences among responses of particular species common to several sites, as well as responses of species diversity in general, could be explained by differences in environmental context across sites. Finally, we found that fertilization altered community structure, by altering the distribution of species rank abundances, and by creating greater spatial heterogeneity. The dataset archived here contains relative abundances by species for ten sites (and many experiments within those sites) in control and fertilized plots. Species traits, productivity, and other environmental data are archived separately but link with this dataset.
Keywords:None:
  • Community ecology (theme)
None:
  • Nitrogen (theme)
None:
  • Fertilization (theme)
None:
  • Relative abundance (theme)
None:
  • Plant (taxonomic)
None:
  • LTER (place)

Involved Parties

Data Set Creators:
Organization:NCEAS 9520: Utilizing meta-analysis and structural equation modeling to disentangle the influences of functional traits and environmental context
Organization:National Center for Ecological Analysis and Synthesis
Individual: Elsa Cleland
Organization:NCEAS
Address:
735, State, St., Suite 300,
Santa Barbara, California 93103 USA
Phone:
8058922522 (voice)
Email Address:
cleland@nceas.ucsb.edu
Data Set Contacts:
Individual: Elsa Cleland
Organization:NCEAS
Address:
735, State, St., Suite 300,
Santa Barbara, California 93103 USA
Phone:
8058922522 (voice)
Email Address:
cleland@nceas.ucsb.edu
Associated Parties:
Individual: Katharine Suding
Individual: Scott Collins
Individual: Chris Clark
Individual: Joe Fargione
Individual: Laura Gough
Individual: Kay Gross
Individual: Steven Pennings
Individual: Daniel Milchunas
Individual: Stephen Cox
Individual: Jim Grace
Metadata Providers:
Individual: Elsa Cleland

Data Set Characteristics

Geographic Region:
Geographic Description:herbaceous communities in North America
Bounding Coordinates:
West:  -143.0000  degrees
East:  -81.0000  degrees
North:  68.0000  degrees
South:  31.0000  degrees
Time Period:
Begin:
1989-07-01
End:
2005-07-01

Sampling, Processing and Quality Control Methods

Step by Step Procedures
Step 1:  
Description:

Methods in brief for each site in the synthetic dataset

At the Arctic LTER site there were 5 experiments conducted in distinct community types, contact Laura Gough for original data. 10 g/m2 N added as NH4-NO3, experiment began 1985, relative abundances of plant species were calculated from percent cover measures based on 1m2 plots, the data here are from 1998. Biomass data are also available for 4 of the 5 experiments.

At the Carpinteria California coastal marsh there were 6 experiments conducted in distinct community types, contact Steven Pennings for original data. 420 g/m2 N was added in the first year (1999) and 820 g/m2 was added in subsequent years in the form of pellets, 20:10:5 NPK, derived from ureaformaldehyde and ammoniated phosphate. Relative abundance was calculated from percent cover measured on 0.25 m2 plots. The data here are from 1999-2005. Biomass data were not collected.

At the Cedar Creek LTER experiments were conducted in old-fields of different ages, 2 experimental fields are included in this dataset, contact Chris Clark for original data. 9.52 g/m2 added as NH4-NO3, experiment began 1982, relative abundance was calculated from biomass harvests from 0.3m2 plots. The data here are from 1999-2001.

At the Georgia Coastal Ecosystems LTER 5 experiments were conducted in distinct community types along a tidal gradient, contact Steven Pennings for original data. 1560 g/m2 N was added as pelletized 29:3:4 NPK, experiment lasted two years 1996 and 1997, only 1997 data is included here. Relative abundance was measured with a biomass harvest on 0.25 m2 plots.

The Jasper Ridge Global Change Experiment is located near Stanford University in California. This is a factorial experiment with 4 treatments - the N addition and water addition treatments are included in this dataset and defined as 2 experiments. Additional warming and elevated CO2 treatments are not included - contact Elsa Cleland for original data. 7 g/m2 N was added as calcium nitrate, experiment began in 1998, relative abundance was calculated from pin counts performed on a 0.5 m2 plot. The data here are from 1998-2002. Biomass data are also available.

At the Kellogg Biological Station LTER 2 experiments were conducted in oldfields that are annually tilled versus un-tilled, contact Kay Gross for original data. 12.3 g N/m2 added as NH4-NO3, experiment began in 1989 and is ongoing, the data here are from 1989-2001. Relative abundance is based on a biomass harvest, plot size varied over time 1989 = 0.2 m2, 1990-1991 = 0.3 m2, 1992-2001 = 1 m2.

This synthetic dataset contains 8 experiments from the Konza Prairie LTER. 4 are from a factorial burning, mowing and fertilization experiment where additional P treatments are coded as blocks (none added block = 1, P added block=2). The other 4 experiments are from a factorial N x water x location experiment (uplands versus lowlands). Contact Scott Collins for additional data.

At the Niwot Ridge LTER, 2 experiments were conducted in dry versus wet meadow communities, contact William Bowman for original data. N was added as liquid urea, the amount varied among years, 25 g/m2 was added in 1990, none in 1991, 10 g/m2 1992-2000. Relative abundance calculated based on pint hits in 1m2 plots using a point frame. Note, blocking indicates P addition (1=none, 2=P added). Data for the wet meadow are from 1990-1996, data for the dry meadow are from 1990-2000 with 1997 and 1999 missing. Biomass data were also collected.

At the Sevilletta LTER, 1 experiment was conducted that included a P addition, this is indicated with a blocking factor as described in the column heading, contact Scott Collins for original data. N was added as… Relative abundance was calculated based on percent cover measures in a 1m2 plot. Experiment began in… Data here are from 2004 and early 2005, biomass was not collected.

At the Shortgrass Steppe LTER, 2 experiments (actually with and without water addition), contact Bill Lauenroth for original data. 6 g/m2 N was added yearly 1997-2000, 3 g/m2/yr 2001-present, in the form of NH4-NO3. Relative abundance is based on percent cover measured in 0.1m2 plots. Data here is from 2000, biomass data were also collected.
Sampling Area And Frequency:
Please see methods description for temporal coverage at each site
Sampling Description:
Please see methods description for sampling design at each site

Data Set Usage Rights

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Access Control:
Auth System:knb
Order:denyFirst
Metadata download: Ecological Metadata Language (EML) File