Establishment from seed is more important for exotic than for native plant species
Data files
Dec 18, 2023 version files 41.98 KB
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mixtures.csv
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monocultures_(1).csv
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nbe.csv
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README.md
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repeated_S_with19.csv
Abstract
Climate change has initiated the movement of both native and non-native (exotic) species across the landscape. Exotic species are hypothesized to establish from seed more readily than comparable native species. We tested the hypothesis that seed limitation is more important for exotic species than native grassland species. We compared seed limitation and invasion resistance over three growing seasons between 18 native and 18 exotic species, grown in both monocultures and mixtures in a field experiment. Half of the plots received a seed mix of the contrasting treatment (i.e. exotic species were seeded into native plots, and native species were seeded into exotic plots), and half served as controls. We found that 1) establishment in this perennial grassland is seed limited, 2) establishment from seed is greater in exotic than native species, and 3) community resistance to seedling establishment was positively related diversity of extant species, but only in native communities. Native-exotic species diversity and composition differences did not converge over time. Our results imply that native-to-exotic transformations occur when diversity declines in native vegetation and exotic seeds arrive from adjacent sites, suggesting that managing for high diversity will reduce transformations to exotic dominance.
README: Establishment from seed is more important for exotic than for native plant species
https://doi.org/10.5061/dryad.k3j9kd5fh
Four data sets, all csv files.
CSV File Name - repeated_S_with19.csv.
Block: October 2007, or March 2008 planting date
Column: Plot location on grid
Row: Plot location on grid
Origin: Native or Exotic
REP: Replicate
Irrig: Irrigated with 128 mm of water or 0 mm of water
Seed: Seeds added or not
draw: Replicate draw
S708: Richness in first week in July, 2008
S1008: Richness in October 2008
S609: Richness in June 2009
S1009: Richness in October 2009
S610: Richness in June 2010
S1010: Richness in October 2010
S1011: Richness in October 2011
S612: Richness in June 2012
S1012: Richness in October 2012
S613: Richness in June 2013
S1013: Richness in October 2013
S614: Richness in June 2014
S1014: Richness in October 2014
S615: Richness in June 2015
S1015: Richness in October 2015, when seed additions were made
S616: Richness in June 2016
S1016: Richness in October 2016
S617: Richness in June 2017
S1017: Richness in October 2017
S618: Richness in June 2018
S1018: Richness in October 2018
S619: Richness in June 2019
CSV File Name: mixtures.csv
Data collected from mixture plots. Columns:
Added: Seed added or not
Block: Plot location on a grid
Column: Plot location on a grid
Row: Plot location on a grid
Origin: Native or Exotic
Irrig: Irrigated with 128 mm per year or 0 mm per year
draw: Replicate draw
Date: Month and year
Rich: Number of plant species
AddRich: Number of new plant species from seed additions
Count: Number of seedlings in plot
TotalRich: Total species richness
CSV File Name: Monocultures.csv
Data collected from monoculture plots. Columns:
id: Observation number
Block: Planted in October 2007 or March 2008
C: Plot location in a grid (Column)
R: Plot location in a grid (Row)
Origin: Native or Exotic
Irrig: Irrigated with 128 mm or 0 mm per year
Added: Seeds added or not
Pair: Species phylogenetic pair
Treat: Species added (seeds added) or not (no seeds added)
Ct617: Seedling count in June 2017
Ct1017: Seedling count in October 2017
Ct618: Seedling count in June 2018
Ct1018: Seedling count in October 2018
Ct619: Seedling count in June 2019
*CSV file name nbe.csv *
Columns:
Plot: Observation number
Block: Planted in Oct. 2007 or March 2008
C: Plot location in a grid (Column)
R: Plot location in a grid (Row)
Origin: Native or Exotic
Irrig: Irrigated with 128 mm or 0 mm per year
Date: Month and Year
Draw: Replicate draw
Added: Seeds added (Y) or Not (N)
sumO: sum seedlings observed
sumE: expected number of seedlings
OvsE: sumO - sumE
sign: sign
lnOvsE: ln transformed OvsE
lOvsE: ln transformed OvsE with original sign
Methods
Experiment established in 2008 compared all native vs. all exotic plant communities and monocultures, with and without summer irrigation (128 mm per year), called MEND (Maintenance of Exotic vs. Native Diversity). In October 2016, a seed addition experiment was conducted on this experiment. Number of seedlings were measured in each plot (seeded and controls), number of plant species was recorded over time.