Niche conservatism and sympatric parallel evolution may help to maintain eight nascent tree taxa along a sharp elevation gradient
Data files
Jun 16, 2025 version files 521.38 KB
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1_Stacy_Ostertag_initial_morphology.csv
155.64 KB
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2_Stacy_Ostertag_final_morphology_and_growth.csv
145.59 KB
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3_Stacy_Ostertag_survivorship.csv
208.16 KB
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4_GPS_waypoints_53_seed_trees.csv
2.56 KB
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README.md
9.43 KB
Abstract
Patterns of niche partitioning among closely related taxa, such as those in incipient adaptive radiations, can provide clues into how niches are created, partitioned, and integrated over ecological and evolutionary time scales. Hawaiian Metrosideros is a ~3-MYO adaptive radiation of trees that dominates the Hawaiian Islands in continuous stands within islands and allows examination of niche partitioning at the early stages of adaptive radiation. We monitored growth and survivorship in a greenhouse over two years of seedlings derived from open-pollinated fruits of eight Metrosideros taxa distributed along the elevation gradient of Koʻolau Volcano, Oʻahu, under four combinations of light and phosphorus. We included four glabrous taxa, representing mixed lineages, and four pubescent taxa, representing a single, Oʻahu-endemic lineage and tested hypotheses of differentiation among taxa and between glabrous and pubescent groups. Several phenotypic traits were measured at the start and end of the two-year experiment, with additional measures at the end. Initial and final morphological measures were used to assess the retention of taxon-diagnostic traits at the two stages and the related measure of plasticity after two years of growing under contrasting environmental conditions. Variation in relative growth rates and survivorship was examined across taxa, between glabrous and pubescent groups, and across relative elevations within Ko`olau Volcano (1-4: low to high). Finally, Pianka's niche overlap index was estimated for all taxon pairs.
Dataset DOI: 10.5061/dryad.w3r22813x
Description of the data and file structure
These 4 files include seedling morphological data recorded at the start and end of the 2-year greenhouse experiment in which seedlings of 8 Oahu Metrosideros taxa were grown under 4 combinations of light and phosphorus. Also included are measures of relative growth rate (RGR) and biweekly survivorship throughout the experiment.
Files and variables
File: 1_Stacy_Ostertag_initial_morphology.csv
Description: Morphology of seedlings at the start of the experiment.
Variables
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abs_ID: (character) = absolute plant ID
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light: (character) = Low, High
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phosphorus: (character) = Low, High
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taxon: (character) = eight letters representing eight taxa
B = Metrosideros polymorpha race B, C = M. polymorpha race C, F = M. polymorpha race F, I = M. polymorpha variety incana, L = M. polymorpha race L, R = M. rugosa, T = M. tremuloides, Z = M. polymorpha race Z. Taxon descriptions and diagnostic key are provided in: Stacy, E. A., T. Sakishima, H. Tharp, and N. Snow. 2020. Isolation of Metrosideros ('Ohi'a) taxa on O`ahu increases with elevation and extreme environments. Symposium Issue; Journal of Heredity 111: 103-118.
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family: (character) = ID of maternal tree from which seeds were sampled to produce seedlings for study
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elevation_category: (numeric) = 1,2,3,4 for lowest to highest
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glabrous_or_pubescent: (character) = G, P for glabrous, pubescent
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initial_measure_date: (MM/DD/YEAR) = date of initial morphological measurements
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no_stems: (numeric) = number of stems
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main_stem_length_cm: (numeric) = main stem length (cm)
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cumulative_stem_length_cm: (numeric) = cumulative stem length (cm)
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no_leaves: (numeric) = number of leaves
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leaf_length_mm: (numeric) = leaf length (cm)
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leaf _width_mm: (numeric) = leaf width (cm)
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leaf_shape(llength/lwidth): (numeric) = leaf shape (leaf length/leaf width)
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petioles: 0,1 for absent, present
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pot_type: (character) = pot, dibble
File: 2_Stacy_Ostertag_final_morphology_and_growth.csv
Description: The initial morphology measures above are included in this file as well as measures taken at end of the experiment.
Variables
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abs_ID: (character) = absolute plant ID
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light : (character) = Low, High
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phosphorus: (character) = Low, High
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taxon: (character) = eight letters representing eight taxa
B = Metrosideros polymorpha race B, C = M. polymorpha race C, F = M. polymorpha race F, I = M. polymorpha variety incana, L = M. polymorpha race L, R = M. rugosa, T = M. tremuloides, Z = M. polymorpha race Z. Taxon descriptions and diagnostic key are provided in: Stacy, E. A., T. Sakishima, H. Tharp, and N. Snow. 2020. Isolation of Metrosideros ('Ohi'a) taxa on O`ahu increases with elevation and extreme environments. Symposium Issue; Journal of Heredity 111: 103-118.
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family: (character) = ID of maternal tree from which seeds were sampled to produce seedlings for study
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initial_measure_date: (MM/DD/YEAR) = date of initial morphological measurements
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no_stems_initial: (numeric) = number of stems
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no_stems_final: (numeric) = final number of stems
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RGR_no_stems: (numeric) = number-of-stems relative growth rate
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main_stem_length_cm_initial: (numeric) = main stem length (cm)
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main_stem_length_cm_final: (numeric) = final main stem length (cm)
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RGR_main_stem_length: (numeric) main-stem-length relative growth rate
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cumulative_stem_length_cm_initial: (numeric) = cumulative stem length (cm)
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cumulative_stem_length_cm_final: (numeric) = final cumulative stem length (cm)
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RGR_cum_stem_length: (numeric) cumulative-stem-length relative growth rate
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no_leaves_initial: (numeric) = number of leaves
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no_leaves_final: (numeric) = final number of leaves
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RGR_no_leaves: (numeric) number-of-leaves relative growth rate
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leaf_length_mm_initial: (numeric) = leaf length (cm)
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leaf_length_mm_final: (numeric) = final leaf length (cm)
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leaf _width_mm_initial: (numeric) = leaf width (cm)
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leaf _width_mm_final: (numeric) = final leaf width (cm)
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leaf_shape_final: (numeric) = leaf shape (leaf length/leaf width) at final
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petioles_initial: 0,1 for absent, present
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petioles_final: 0,1 for absent, present at final
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mature_phenotype_reached_at_final?: 0,1 for no, yes
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aerial_root_length_cm_final: aerial root length (cm) at final
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aer_root_length/cumulative_stem_length_final: [aerial root length (cm)]/[cumulative stem length (cm)]
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leaf_pubescence_score_final: abaxial leaf pubescence score at final (0, 0.5, 1, 1.5, 2, such that 0 = glabrous; 0.5, 1, 1.5 = pubescence that rubs off with little, moderate, and strong effort, respectively; and 2 = permanent pubescence)
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pot_type: (character) = pot, dibble
File: 3_Stacy_Ostertag_survivorship.csv
Description: The descriptor variables in the first 7 columns are identical to those in the above files. The remaining columns indicate mortality (with an X) and its timing across the 2-year experiment. The final column, "dead_or_alive_1July15" indicates the state of each seedling at the end of the experiment (0,1 for dead, alive).
Variables
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abs_ID: (character) = absolute plant ID
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light : (character) = Low, High
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phosphorus: (character) = Low, High
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taxon: (character) = eight letters representing eight taxa
B = Metrosideros polymorpha race B, C = M. polymorpha race C, F = M. polymorpha race F, I = M. polymorpha variety incana, L = M. polymorpha race L, R = M. rugosa, T = M. tremuloides, Z = M. polymorpha race Z. Taxon descriptions and diagnostic key are provided in: Stacy, E. A., T. Sakishima, H. Tharp, and N. Snow. 2020. Isolation of Metrosideros ('Ohi'a) taxa on O`ahu increases with elevation and extreme environments. Symposium Issue; Journal of Heredity 111: 103-118.
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family: (character) = ID of maternal tree from which seeds were sampled to produce seedlings for study
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initial_measure_date: (date) = date of initial morphological measurements
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pot_type: (character) = pot, dibble
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mortality_8/12/2013: blank or X for alive or dead, respectively
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8/30/2013: blank or X for alive or dead, respectively
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9/17/2013: blank or X for alive or dead, respectively
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10/1/2013: blank or X for alive or dead, respectively
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10/14/2013: blank or X for alive or dead, respectively
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10/30/2013: blank or X for alive or dead, respectively
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11/13/2013: blank or X for alive or dead, respectively
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11/27/2013: blank or X for alive or dead, respectively
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12/18/2013: blank or X for alive or dead, respectively
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1/7/2014: blank or X for alive or dead, respectively
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1/28/2014: blank or X for alive or dead, respectively
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2/14/2014: blank or X for alive or dead, respectively
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3/1/2014: blank or X for alive or dead, respectively
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3/15/2014: blank or X for alive or dead, respectively
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4/1/2014: blank or X for alive or dead, respectively
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4/15/2014: blank or X for alive or dead, respectively
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5/1/2014: blank or X for alive or dead, respectively
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5/15/2014: blank or X for alive or dead, respectively
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6/1/2014: blank or X for alive or dead, respectively
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6/15/2014: blank or X for alive or dead, respectively
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7/1/2014: blank or X for alive or dead, respectively
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7/15/2014: blank or X for alive or dead, respectively
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8/1/2014: blank or X for alive or dead, respectively
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8/15/2014: blank or X for alive or dead, respectively
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9/1/2014: blank or X for alive or dead, respectively
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9/15/2014: blank or X for alive or dead, respectively
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10/1/2014: blank or X for alive or dead, respectively
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10/15/2014: blank or X for alive or dead, respectively
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11/1/2014: blank or X for alive or dead, respectively
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11/15/2015: blank or X for alive or dead, respectively
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12/1/2014: blank or X for alive or dead, respectively
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12/15/2014: blank or X for alive or dead, respectively
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1/1/2015: blank or X for alive or dead, respectively
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1/15/2015: blank or X for alive or dead, respectively
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2/1/2015: blank or X for alive or dead, respectively
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2/15/2015: blank or X for alive or dead, respectively
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3/1/2015: blank or X for alive or dead, respectively
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3/15/2015: blank or X for alive or dead, respectively
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4/1/2015: blank or X for alive or dead, respectively
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5/1/201: blank or X for alive or dead, respectively
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6/1/2015: blank or X for alive or dead, respectively
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7/1/2015: blank or X for alive or dead, respectively
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dead_or_alive_1July15: 0 or 1 for dead or alive, respectively, at end of experiment
File: 4_Stacy_Ostertag_GPS_waypoints_seed_trees
Description: GIS waypoints and altitudes of the 53 trees on O`ahu from which seeds were collected to generate seedlings.
- seed_tree_ID (character) = lab absolute identifier for maternal tree on O`ahu from which seeds were collected to generate seedlings
- volcano (character) = volcano ID on O`ahu
- taxon_code (character) = eight letters representing eight taxa
- leaf_phenotype (character) = G, P for glabrous, pubescent
- latitude (numeric) = latitude (decimal degrees)
- longitude (numeric) = longitude (decimal degrees)
- altitude_m (numeric) = altitude of waypoint (meters above sea level)