Cover estimation

Estimate the percentage of ground surface covered by:

• Lichens (%)

• Mosses (%)

• Or combined lichen–moss cover (%)

Cover is defined as the vertical projection of living material onto the ground surface.

Estimation methods

• Visual estimation (standard approach):

• Use cover classes (optional), e.g.:
  • 0–5%
  • 5–25%
  • 25–50%
  • 50–75%
  • 75–100%

• Grid-based quadrats (recommended for higher precision):

• Subdivide quadrat into equal cells
• Count occupied cells to estimate cover

Vegetation and substrate analysis (optional)

This complementary method of assessing substrate coverage provides valuable context for woody debris interactions. This can be linked to debris dynamics, as the structure of the substrate can affect both moisture retention and habitat availability for various species.

• The vegetation data is collected within predefined quadrats (e.g., 50 cm diameter circles, subdivided into 625 cm² squares), and coverage is estimated by counting grid units with ≥50% coverage by bryophytes, lichens, or cyanophytes. 
• For substrate types, three categories are defined based on physical characteristics: conglomerates, large pebbles (≥10 cm²), and small pebbles/sand/clay. 
• The coverage of each category is measured using ImageJ software, which allows for automated analysis of field photographs. 

Sample storage

Not required unless species identification is uncertain.

If samples are collected:

• Store in paper envelopes (avoid plastic)
• Label clearly with location and date
• Air-dry before laboratory identification

Variables recorded

• Site and plot ID
• GPS coordinates
• Date and time
• Fire history / burn severity (if available)
• Quadrat size
• Lichen cover (%)
• Moss cover (%)
• Total ground cover (%)

Optional:

• Species composition
• Substrate type (soil, rock, wood)
• Moisture conditions

Special considerations

• Training and calibration of observers are recommended prior to fieldwork to minimise observer bias and ensure consistency in percentage cover estimates
• Seasonality: Moisture conditions can influence detectability and appearance
• Post-fire conditions: Ash, char, and soil darkening may complicate cover estimation
• Species differentiation: Distinguishing lichens from mosses may require expertise
• Spatial heterogeneity: Increase sampling intensity in patchy environments
• Substrate composition analysis, particularly related to the physical properties of the ground (e.g., conglomerates, pebbles, and finer particles), which influences species distribution and biomass accumulation in rocky ecosystems.