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Highly-replicated soil, topography and vegetation sampling across an old-growth tropical rain forest landscape

Cite this dataset

Clark, David et al. (2022). Highly-replicated soil, topography and vegetation sampling across an old-growth tropical rain forest landscape [Dataset]. Dryad. https://doi.org/10.5061/dryad.tqjq2bw23

Abstract

Here we present data from highly-replicated sampling of soil, topography, and vegetation across an old-growth tropical rainforest landscape at the La Selva Biological Station, Costa Rica.  Samples were taken at 100 x 50 m spacing using an existing surveyed grid system.  The 573-ha sample area spanned a variety of soil, topographic and vegetation conditions, including flat terraces on old alluvial soil, ridge tops and steep slopes on residual soil, riparian habitats and fresh-water swamps.  At each of 1170 grid points we established a circular 0.01 ha quadrat (radius = 5.64 m).  We sampled soil at 30-50 cm depth with a soil augur and collected a sample for subsequent analysis.  We measured slope angle with a clinometer and slope direction with a compass.  We measured stem diameter to +1 mm with a synthetic fabric diameter tape for all stems >10 cm diameter (N= 5236) at 1.3 m from the ground or to ~ 6 m height if there were basal irregularities.  We classified stems to life form (tree, palm, liana), and identified all trees and palms to species or morphospecies (N=266; lianas were not identified to species).  We collected vouchers from all trees that we could not positively identify in the field (N=920).

As a whole the data set presents an integrated view of soil, topography and vegetation across a mesoscale old-growth tropical rain forest landscape.  The data have been used to refine a reserve-wide soils map for La Selva, and for a variety of papers analyzing the interactions of soil, topography and species distributions at landscape scales (see the 10 papers listed in the Related Works section below).

There are no restrictions at all on the use of these data, and we think they will be useful for teaching and analysis projects as well as further original research applications.  The data also provide a detailed benchmark of the status of old-growth vegetation in 1993-95 for one of the most intensively studied tropical rain forest landscapes in the world.  Because the data are accurately georeferenced and detailed metadata on all methods are provided, this study could be repeated at any time to assess the trajectory of vegetation changes at La Selva, particularly in relation to local disturbances and changing regional and global climates.   

Methods

Here we document the methods used for the soil and topography sampling, measurements of stem diameters for all individuals, and for identification of the tree and palm species.

Soil samples were taken at 30-50 cm depth and a sample retained for further analysis.  Slope angle in the direction of water runoff was measured with a Suunto clinometer ­+ 1 degree and slope azimuth in the same direction was measured with a Suunto compass + 1 degree.  See details in the file Vegetation map protocols original with Eng trans.pdf.  Development of the revised La Selva soils maps from the soil samples is described in detail on pg. 102-104 in Clark, D.B., D.A. Clark and J.M. Read (1998, Journal of Ecology 86:101-112), and on pg. 25 Clark D.A. (1998, Annals of the Missouri Botanical Garden 85:18-33).  Detailed descriptions of how the larger soil units were analyzed based on these samples is given in Clark soil mapping units description.pdf.

Methods for establishing each 0.01 ha plot and measuring stem diameters are given in Vegetation map protocols original with Eng trans.pdf.

Most trees and palms species were identified in the field, mostly by the paraforesters Leonel Campos Otoya and William Miranda Conejo, with minor contributions from David B. Clark and Deboarh A. Clark.  For species that could not be positively identified in the field we collected voucher specimens (N= 920).  Voucher numbers are listed in the individuals table LaSelvaIndividualsTable.csv.  The identification of each voucher is documented in La Selva vegetation map vouchers list.pdf.  The original field work was completed in 1995.  Since that time there have been extensive changes in the taxonomy of tropical plants in general and of the family, genus and species names for La Selva species in particular.  The updated through 2022 family, genus and species names for the taxa sampled here are given in Species names Vegetation Map 2022.csv.  The variable Genus_Species_95 can be used to link the 1995 names in LaSelvaIndividualsTable.csv to the same taxon in Species names Vegetation Map 2022.csv.

Data from the original field sheets (La Selva vegetation map scanned field sheets.pdf) were entered into two files and checked by readback.  The individual stems data (location, identifications, stem diameters) were entered into LaSelvaIndividualsTable.csv, and the soil and topographic data for each sample were entered into LaSelvaQuadratsData.csv.  The data have not been further processed in these files.

Usage notes

The data and metadata are in csv txt files and pdf files, and require no special software to open and fully use.

Funding

Andrew W. Mellon Foundation