Identification

Title

Seedling growth responses to experimental soil warming in a tropical forest, Panama, 2016-2022

Abstract

Growth parameters for tree seedlings in a lowland tropical forest in Panama, subject to experimental soil warming. The experiment is situated at the Soil Warming Experiment in Lowland Tropical Rainforest (SWELTR) on Barro Colorado Island in Panama, where the whole soil profile is subject to warming by 4-degrees. Seedling species are Inga laurina, Ormosia macrocalyx, Tachigali versicolor, Lacmellea panamensis, Protium pittieri and Virola surinamensis. Data are seedling parameters: relative growth rates, height change over time, herbivory index, light-saturated photosynthesis (Amax), leaf chlorophyll concentration, light (photosynthetic photon flux density; PPFD). We also determined soil nutrient (N and P) mineralisation for the same period using in situ ion-exchange resins each month. Data were collected over the period 2016 to 2020, following 3 years of soil warming. Photosynthesis and leaf chlorophyll content index data were collected in field campaigns during 2019 and 2022, respectively. Full details about this dataset can be found at https://doi.org/10.5285/3a4aabba-e790-4ac3-b845-936790768330

Resource type

dataset

Resource locator

https://data-package.ceh.ac.uk/data/3a4aabba-e790-4ac3-b845-936790768330

description: Download a copy of this data

function: download

https://data-package.ceh.ac.uk/sd/3a4aabba-e790-4ac3-b845-936790768330.zip

description: Supporting information available to assist in re-use of this dataset

function: information

Unique resource identifier

code

https://catalogue.ceh.ac.uk/id/3a4aabba-e790-4ac3-b845-936790768330

codeSpace

doi:

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

biota

Keywords

Geographic location

West bounding longitude

-79.871

East bounding longitude

-79.818

North bounding latitude

9.182

South bounding latitude

9.13

Temporal reference

Temporal extent

Begin position

2016-01-01

End position

2022-12-31

Dataset reference date

date type

publication

effective date

2023-06-01

Frequency of update

Quality and validity

Lineage

Data were collected over the period 2016-2019, with seedling census each 3-months and soil parameters determined monthly. Seedling height was determined by measuring from the soil surface to the shoot apex (apical meristem), using a tape measure. Light was determined by PPFD (Photosynthetic Photon Flux Density; µmol m-2 s-1), measured using a LI-250A light meter (LI-COR, Inc., Lincoln, NE, USA). PPFD was determined monthly above each individual seedling, both on an overcast day and a clear day for each month, providing two metrics of PPFD representing the average conditions on both an overcast and clear day. Light saturated photosynthesis (Asat) was determined using a portable photosynthetic system (LI-6400, LI-COR, Inc., Lincoln, NE, USA) fitted with a standard 2 × 3 cm leaf cuvette with a red-blue LED light source (6400-02B)) and a CO2 mixer (6400-01, LI-COR, Inc., Lincoln, NE, USA). To assess whether soil warming affected nutrient availability to plants, we determined soil nitrogen (N) and phosphorus (P) mineralisation using in situ mixed-bed ion exchange resin membranes (Dowex Marathon Mr-3, Sigma-Aldrich). Resin was prepared by rinsing in 0.5 M HCl for 2 hours and then rinsed with DI H2O. Resin was placed inside nylon bags (5 g resin in each) and installed at 5 cm soil depth in systematically distributed locations in each plot (n = 5 per plot). Resin bags were deployed monthly for three years, and following collection were stored at 4oC until extraction. Extraction was performed using 0.5 M HCl, and PO4, NH4 and NO3, were determined using a Lachat Quickchem 8500 flow injection analyzer (Hach Co., Loveland, CO). Extractable PO4 (total mineralised P) and NH4 and NO3 (total mineralized N) were calculated from the difference between extracted N from resin deployed in the field and resin not deployed (blanks) and expressed as extractable PO4-P, NH4‐N and NO3‐N per g resin per day. We determined relative growth rates (RGR) using a first order power-law model, which is especially suitable for the early stages of seedling growth when growth is rapid and non-asymptotic, but slowing over time: dh / dt = tβ where dh/dt is height increment over time (or RGR). To represent time in our models we used ‘relative month’ where the warming treatment began at relative month = 0. To calculate the power of the relationship (β), we used log-log plots. We determined RGR for each individual seedling (n = 30, 6 individuals per 5 plots; and for 6 species), by calculating the slope of log [seedling height]/log [time in months]. We used the power rate increase β to assess treatment effects on RGR. All data were subject to quality control review prior to statistical analyses in R, by assessing outliers, to ensure correct identification of seedlings and correct use of blanks/standards for determination of final values.

Conformity

Conformity report

specification

title

Commission Regulation (EU) No 1089/2010 of 23 November 2010 implementing Directive 2007/2/EC of the European Parliament and of the Council as regards interoperability of spatial data sets and services