Data from: Annual species’ experimental germination responses to light and temperature do not correspond with their microhabitat associations in the field
Data files
Apr 02, 2024 version files 2.21 MB
-
baseline.csv
5.93 KB
-
cumulative_curve.csv
11.17 KB
-
germ_cue.csv
11.81 KB
-
Germination_Occurrence.html
2.03 MB
-
legend_point.csv
3.20 KB
-
occurrence.csv
141.69 KB
-
README.md
4.20 KB
-
seed_mass.csv
616 B
Abstract
Annual species have evolved sets of germination cues that are thought to be predictive of the post-germination environment. In naturally patchy environments, germination microsites often vary considerably in the amount of light they receive and in the diurnal temperature fluctuations they experience. However, whether species’ differential germination responses to light and temperature are associated with their spatial patterns of occurrence remains largely untested.
We surveyed species’ occurrences in annual plant communities in 150 quadrats across gradients of canopy cover and litter cover. Nineteen species recorded in this survey were then included in a germination experiment that manipulated (1) Light vs. Dark (12h light or continuous dark) approximating seeds near the soil surface versus those covered by litter and (2) Cold vs. Warm temperature regimes (7/18 °C and 7/24 °C) approximating diurnal fluctuations experienced in shaded versus sun-exposed microsites, respectively.
In the germination experiment, six species had highest germination probabilities in the Light treatment (regardless of temperature), five in Cold + Light, one in Warm + Light, two were indifferent to the treatments, and four did not germinate at all. Binomial linear mixed-effects models showed that species’ maximum responses to light and temperature did not explain their spatial distributions along canopy cover and litter cover gradients, contrary to theoretical expectations of germination being a strong driver of species’ occurrences.
Despite variation in species’ responses to experimental treatments, no association was found with their field microsite associations. Germination strategies in our system were wider than expected for Mediterranean systems. Our results support that germination cues are not strong drivers of microhabitat associations in this system.
README: Annual species’ experimental germination responses to light and temperature do not correspond with their microhabitat associations in the field
Date created 01/03/2024
Authors:
Isis A. da Silva, School of the Environment, The University of Queensland, St Lucia, QLD, Australia
David J. Merrit, Kings Park Science, Department of Biodiversity Conservation and Attractions, Kings Park, WA, 6005, Australia and School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
Todd E. Erickson, Kings Park Science, Department of Biodiversity Conservation and Attractions, Kings Park, WA, 6005, Australia and Centre for Engineering Innovation: Agriculture and Ecological Restoration, School of Agriculture and Environment, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
Margaret M. Mayfield, School of Biosciences, The University of Melbourne, Parkville, VIC, Australia
John M. Dwyer, School of the Environment, The University of Queensland, St Lucia, QLD, Australia
Below are the metadata for data files
-> Germination_Occurrence.html contain code summary and all outputs including tables and figures and can be used to understand the analyses without R;
To run all analyses:
(1) Download and unzip the "Germination_Occurrence_Project" folder from Zenodo;
(2) Create a "Data" and a "Outputs" folder into "Germination_Occurrence_Project";
(3) Download the data files (".csv") and save inside the "Data" folder;
(4) Open the "Germination_Occurrence_Project.Rproj" file and then run Germination_Occurrence.Rmd script
Datasets associated with this analysis:
"baseline.csv"
Data for calculating mean germination percentage of fresh seeds
species- taxon scientific name
treatment - experimental conditions in which germination was monitored. Light is 12h/12h dark/light and Dark is continuous darkness
rep- Replicate or Petri dish
day_41- day of the first monitoring
day_56- day of the second monitoring
"cumulative_curve.csv"
Data for cumulative germination curve for the main experiment
species- taxon scientific name
temp- temperature treatment. Cold (7/18°C) or Warm (7/24°C)
light- light treatment. Light is 12h/12h dark/light and Dark is continuous darkness
total_seeds_dish- is the total seeds sown in each dish
total_seeds- total number of seeds sown per treatment per species
dish- Replicate or Petri dish
2 to 32: number of germinants in each monitoring day
"germ_cue.csv"
Data for main analysis of germination responses to experimental treatments
species- taxon scientific name
temp- temperature treatment. Cold (7/18°C) or Warm (7/24°C)
light- light treatment. Light is 12h/12h dark/light and Dark is continuous darkness
total_seeds_dish- is the total seeds sown in each dish
dish- Replicate or Petri dish
germination_total- total seeds that germinated in each petri dish by the end of the experiment
"legend_point.csv"
Data containing legends for Figure 3. Cells containing NA mean "Not Applicable".
species- taxon scientific name
Treatment- treatment combinations from Pairwise analyses. Treatments were Cold (7/18°C), Warm (7/24°C),Light (12h/12h dark/light), Dark (continuous darkness).
x and y - coordinates for placing the labels
label- labels summarizing the results from the pairwise analyses to be plotted
"occurrence.csv"
Data containing occurrence data from the field
id- block and plot ids combined
species- taxon scientific name
plot- id of 30 x 30 cm quadrats in which occurrence data was surveyed, there 150 in total
block- iq of block (15 x 15 m) in which quadrats were placed, there were 10 in total
occurrence - binary variable for the presence absence of species in each quadrat/block combination
canopy_cover - the percentage of tree canopy cover at each quadrat using a spherical densiometer
litter_percent - the percentage of litter estimated by overlaying a 100-point grid on quadrat photos and counting all intersections covered by leaves or fallen branches
"seed_mass.csv"
Data containing seed mass values for species with sufficient germination
species- taxon scientific name
mean_SM - mean values of seed mass (mg)
Methods
We surveyed species’ occurrences in annual plant communities in 150 quadrats across gradients of canopy cover and litter cover. Nineteen species recorded in this survey were then included in a germination experiment that manipulated (1) Light vs. Dark (12h light or continuous dark) approximating seeds near the soil surface versus those covered by litter and (2) Cold vs. Warm temperature regimes (7/18 °C and 7/24 °C) approximating diurnal fluctuations experienced in shaded versus sun-exposed microsites, respectively.
Analyses were performed in R.