Quadrat Survey

Sample within defined square areas recording coverage and abundance.

Overview

Quadrat surveys use fixed-area plots to sample vegetation or other organisms. This method provides quantitative data about community composition and structure.

When to Use Quadrats

• Vegetation community analysis
• Ground cover estimation
• Plant density studies
• Grassland monitoring
• Forest understory surveys

Advantages

• Standardized sampling area
• Reproducible methodology
• Enables statistical comparison
• IVI calculation support

Setting Up Quadrat Surveys

Plot Size Selection

Choose size based on target organisms:

Basic Configuration

Permanent Plots

FieldEco supports marking quadrats as permanent plots for long-term monitoring studies.

Creating Permanent Plots

1. During setup, enable “Mark as Permanent Plot”
2. Record 4-corner GPS coordinates
3. Take site photos for relocation
4. Add distinctive landmarks in notes

4-Corner GPS Recording

Permanent plots record precise GPS coordinates for all four corners:

This enables:

• Precise relocation in future visits
• Exact plot orientation
• GIS mapping of plot boundaries
• Area verification

Session-Based Revisiting

Permanent plots support multiple survey sessions:

1. Create Session: Start a new visit to the plot
2. Previous Data: View historical observations
3. Add Observations: Record new data for this session
4. Compare: Analyze changes over time

Relocation Tips

• Use saved corner coordinates for navigation
• Compare current view with site photos
• Look for marked trees or permanent markers
• Check landmarks noted in previous visits

Data Collection

Recording Species Data

For each species in the quadrat:

1. Species - Identification
2. Count - Number of individuals
3. Coverage - Percent cover (0-100%)
4. Density - Individuals per unit area
5. Frequency - Presence/absence

Vegetation-Specific Fields

• Life Form: Tree, Shrub, Herb, Grass
• Height Class: Ground, Lower, Middle, Upper canopy
• Phenology: Vegetative, Flowering, Fruiting
• Health: Healthy, Stressed, Diseased

For Trees (10m+ plots)

• DBH measurement
• Height estimation
• Crown class
• Basal area

Taxa-Specific Data Collection

Select your taxa group during setup to get specialized data fields.

Plants (2 Methods)

VEGETATION_SURVEY Standard vegetation assessment:

• Species identification
• Count/density
• Percent cover
• Height class
• Phenological state
• Life form (tree, shrub, herb, grass)

TREE_PLOT Detailed tree measurements:

• GBH: Girth at Breast Height (130cm)
• Height: Estimated or measured
• Crown Class: Dominant, Co-dominant, Intermediate, Suppressed
• Canopy Cover: Percent of plot shaded
• Health Status: Healthy, Stressed, Diseased, Dead
• Regeneration: Seedlings, Saplings counted

Invertebrates (2 Methods)

QUADRAT_SAMPLING Standard quadrat counts:

• Species identification
• Count per quadrat
• Microhabitat (soil, leaf litter, vegetation)
• Substrate type

SWEEP_SAMPLING Sweep net within quadrat:

• Number of sweeps
• Specimens collected
• Vegetation type swept
• Time spent sweeping

Coverage Estimation

Visual Estimation Guide

Tips for Accuracy

• Use cover class categories
• Compare with reference photos
• Be consistent across plots
• Note overlapping layers

Analysis Integration

Quadrat data supports:

Importance Value Index (IVI)

IVI = Relative Density + Relative Frequency + Relative Dominance

FieldEco automatically calculates:

• Relative density
• Relative frequency
• Relative dominance (basal area)
• IVI scores

Other Analyses

• Species diversity indices
• Community similarity
• Stand structure metrics
• Basal area summaries

Best Practices

Plot Placement

• Use random coordinates
• Avoid edge effects
• Document placement method
• Mark corners permanently (for monitoring)

Data Quality

• Record all species including unknowns
• Note any disturbance
• Photograph the plot
• Use consistent methodology

Related Documentation

• Transect Survey - Linear sampling
• Vegetation Analysis - IVI calculations
• DBH Calculator - Tree measurements