Common Garden Experiment: Seedling addition experiment - growth and biomass data

Usage Rights

This data is Private.

Dataset Abstract

While coexistence in plant communities is frequently explained by effects of resource niche partitioning, the Janzen-Connell (J-C) hypothesis is an alternative approach that has been assumed as a major ecological mechanism explaining high species richness levels, in particular, in tropical forest ecosystems. Central components of the J-C hypothesis are non-competitive effects of density- and distance-dependence, thereby two drivers that contribute independently to species coexistence, but that are ultimately linked in the field. Here, we make use of the forest Biodiversity-Ecosystem Functioning project in subtropical China (BEF-China) to estimate density and distance dependence effects by means of a reciprocal tree seedling transplant experiment. Using monocultures of ten and seven tree species, respectively planted at two different sites, juveniles of all species were grown in their own (home) and in all other monocultures (away), thereby testing for distance effect, just as in three different levels of planting density, testing for density effects (see "Main Experiment: Seedling addition experiment - growth and biomass data" for further details)

In addition, we repeated a similar set-up in a nearby common garden experiment, where we added a 'shadow' treatment to simulate different light conditions induced by the canopy layer. The general aim of the common garden experiment is to test for additional density dependent intraspecific competition for light in the absence of host-specific agents necessary for J-C effects. Density dependent patterns that are prevalent in the main experiment, while not being prevalent in the common garden experiment can be considered true J-C effects.

Dataset Design

From the 11 different tree species used in the main experiment juvenile plants from 8 different tree species have been implemented in an additional common garden experiment established on a former agricultural used field nearby (former Pilot Experiment). Each species was planted at density levels of 1, 4, 9 and 25 individuals. Each species × density combination was grown in plots either established as 'shadow' or 'light'-treatment (3 replicates each). Each plot consisted of 1 species with 0.5 x 0.5 m2 in size (corresponding to the size of one splitplot of the main experiment). Plots established as 'shadow'-treatment have been surrounded by a container with 1.2 m in height wrapped in a shadow net.

On the north facing site each shadow net was then opened up to 0.5 m in hight to provide a more suitable microclimate and prevent natural enemies exclusion. Each species X density X treatment combination was randomly allocated within the area of approximately 135 m2. The general aim of the common garden experiment is to test for density-dependent intraspecific competition effects as well as light and drought dependent mortality rates by excluding host-specific agents necessary for J-C effects.

Spatial Extent

Pilot experiment

Data columns available in the raw data part of this dataset

Samplenr
An individual number for each taken sample
Data group: Helper
Values
100.01.3
100.01.1
100.01.2
100.02.0
100.01.0
Seedlingnr
An individual number for each seedling
Data group: Helper
Values
100.02
100.05
100.04
100.01
100.03
Plot
Plot
Data group: Helper
Values
100
102
1
103
101
Record
number for the records
Data group: Helper
Values
0
3
2
1
Date
Month and year of record
Data group: Date time information
Values
September_2015
July_2015
August_2015
September_2016
Planted_Species
Species planted. The scientific species fullnames are based on the "Flora of China". Scientific species names consist of epithet and genus.
Data group: Scientific plant species name
Values
D.glaucifolia
C.sclerophylla
C.glauca
C.fargesii
L.formosana
Density
Density of planted species within each splitplot
Data group: Seedling Density
Values
4
25
1
9
Treatment
indicator for species either planted in plots with shadow net (= shadow) or without shadow net (= light); Datagroup description: treatment of each Plot
Data group: Treatment
Values
Shadow
Light
Dead
indicator for species dead (1) or alive (0)
Data group: Living status
Values
0
1
Height_P
Height of the seedling up to the last photosynthetically active tissue
Unit: cm
Data group: Plant height
Values
0
101
10
100
1
Height_G
Height of the seedling up to the last still living tissue
Unit: cm
Data group: Plant height
Values
10.1
10.2
10
10.3
104
Leaves_Liv
Number of living leaves
Data group: Plant leaf number
Values
0
100
101
1
10
Leaves_Dam
Number of damaged leaves
Data group: Plant leaf number
Values
100
10
101
0
1
Leaves_Dead
Number of dead leaves on seedling
Data group: Plant leaf number
Values
0.1
1
13
15
0
Damage_pro
estimated leave damage in percent
Unit: in percent
Data group: Herbivore damage
Values
0.1
0.3
0.5
0
0.2
Biomass_Above
aboveground dry matter biomass in Sep. 2016
Unit: g
Data group: Above and below ground biomass measurement
Values
0.15
0.2
0.21
0.01
0.23
Biomass_Below
belowground dry matter biomass in Sep. 2016
Data group: Above and below ground biomass measurement
Values
0.1
0.05
0.04
0.08
0.09