Santa Cruz island time series vegetation data

Meeder, Annie 1 ; Klinger, Robert2; Yost, Jenn3

Published Aug 13, 2025 on Dryad. https://doi.org/10.5061/dryad.2fqz61327

Data files

Aug 13, 2025 version files 1.49 MB

README.md

8.34 KB
SantaCruzIsland_CoverData_91-95_98_22_Meeder.xlsx

1.49 MB

Aug 13, 2025 version files 1.49 MB

README.md

8.28 KB
SantaCruzIsland_CoverData_91-95_98_22_Meeder.xlsx

1.49 MB

Abstract

Methods

This dataset was collected as part of a long-term vegetation monitoring program on Santa Cruz Island, California, USA, following the removal of non-native grazers. Sampling was conducted across 100 30 x 2 m plots representing a range of plant communities (oak woodland, chaprral, pine, grassland, coastal scrub), restoration histories and management strategies.

Field Methods:
Vegetation surveys were conducted annually during peak biomass (typically between March and May). Within each plot, species presence and cover were recorded using a modified point-intercept method along permanent transects. Each transect consisted of a standardized number of regularly spaced points where all hits were identified to species when possible.

Environmental Data:
In addition to vegetation data, abiotic variables such as slope, aspect, soil type, and elevation were recorded for each plot using GPS, topographic maps, and field observations. Climatic data were interpolated from nearby weather stations and remote sensing sources when relevant.

Data Processing:
Species names were standardized to The Jepson eFlora taxonomy (2022). Percent cover was calculated from point-intercept data and averaged across transects within each plot-year. Quality control steps included filtering misidentifications, removing non-vascular plant records, and excluding plots with incomplete metadata.

Data Structure:
The final dataset includes:

Plot metadata (location, environmental variables, management history),
Annual species composition data (percent cover by species),
and survey year identifiers.

Each row represents a unique plot-year combination, with associated species-level or community-level attributes.

Dataset DOI: 10.5061/dryad.2fqz61327

Description of the data and file structure

README – Santa Cruz Island Post-Grazing Vegetation Monitoring Dataset

Data Description

This dataset was collected as part of a long-term ecological monitoring effort to assess the recovery of native grassland vegetation following the removal of non-native herbivores on Santa Cruz Island, California. The goal of the project is to track plant community composition, diversity, and structural changes over time in response to grazing removal, restoration treatments, and ongoing management.

Sampling was conducted across a network of permanent plots representing varied environmental conditions and restoration histories. These data support analyses of vegetation recovery trajectories, treatment effectiveness, and spatial variation in community assembly.

Methods Summary

Vegetation surveys were conducted annually (1991-1995,1998, 2022) during peak growing season (typically March–May) using point-intercept sampling along permanent transects within each plot. All vascular plant species intercepted at designated points were recorded. Species identifications were standardized to The Jepson eFlora (2022). Cover values were calculated from intercept frequencies and averaged at the plot-year level.

Environmental variables (e.g., elevation, aspect, slope) were collected using GPS and field measurements. Restoration treatment histories were compiled from land management records maintained by The Nature Conservancy and the National Park Service.

Data Usage Notes

Percent cover values are relative to total hits per plot and may not sum to 100%.
Plots with missing survey years or incomplete records are included but should be filtered as needed for analysis.

Citation

If you use these data, please cite both the original manuscript and this Dryad dataset using the provided DOI:

Dataset DOI: https://doi.org/10.5061/dryad.1rn8pk158
Associated manuscript: [Insert citation for EAP25-0109 once available]

Files and variables

Files Included

SantaCruzIsland_CoverData_91-95_98_22_Meeder.xlsx
README.md – This document.

Description: This dataset was collected as part of a long-term ecological monitoring effort to assess the recovery of native grassland vegetation following the removal of non-native herbivores on Santa Cruz Island, California. The goal of the project is to track plant community composition, diversity, and structural changes over time in response to grazing removal, restoration treatments, and ongoing management.

Variables

Column	Variable Name	Description
A	`Acronym`	six-letter species code or abbreviation for plant taxon. first three = first three of genus, second three = second three of specific epithet
B	`Plot`	Plot number (character); identifies permanent sampling location
C	`Year`	Year of vegetation survey
D	`Plotcode`	Unique plot identifier combining plot number and sub-code
E	`Cover`	Cover for the species in that plot-year
F	`Native`	Native status (`T` = native, `F` = non-native)
G	`Guild`	Broad functional group (e.g., Grass, Forb, Shrub)
H	`Lifecycle`	Lifecycle strategy (e.g., Annual, Perennial)
I	`Category`	Combined growth form/lifecycle classification (e.g., `anforb`, `ntvshrub`)
J	`L_OID`	Internal database ID or object identifier for the location
K	`X`	X-coordinate (UTM or projected coordinate system)
L	`Y`	Y-coordinate (UTM or projected coordinate system)
M	`Location`	Site or subregion name (e.g., Loma Peloma)--specific to Santa Cruz Island grazing pasture history.
N	`USGSMap`	Topographic map identifier (e.g., SCIC)
O	`Vegtype`	Vegetation type (e.g., Grassland)
P	`Elevation`	Elevation in meters above sea level
Q	`Slope`	Slope in degrees
R	`Aspect`	Aspect in degrees (0–360)
S	`Aspectcos`	Cosine-transformed aspect (for use in models)
T	`TRI`	Topographic Ruggedness Index
U	`Vegline`	Survey status for vegetation line (e.g., "Complete")
V	`Status`	Survey completeness or QC status
W	`Pasture`	Pasture or grazing management unit
X	Sheep.Grazing	Historical sheep grazing intensity
Y	Cattle.Grazing	Historical attle grazing treatment or classification (e.g., "Medium")
Z	`n`	1

Let me know if you want these saved in a CSV or markdown format for your README, or if you'd like help renaming or reordering columns for clarity in the dataset itself!

Code/software

excel