Lichen for Air Quality Biomonitoring
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Background
Lichen are not plants, but rather a symbiotic relationship between fungi and algae and/or cyanobacteria. Macrolichen (leafy or bushy lichen) that grow on trees obtain all their nutrients from the surrounding air, moisture, and rain, which means that they also absorb many of the chemicals and pollutants present in the air and can serve as mini living air quality monitors, or bioindicators. You can learn more about lichen and their main functional groups in this research note
This page will hopefully be helpful to folks at various stages in the air quality study design process. Anyone just starting to design an air quality study or reassessing an ongoing study can use this wiki to assess whether bioindicators can and should be integrated into the study.
Use Cases and Limitations
There are many benefits to using lichen to assess air quality compared to traditional instrumentation. Namely, biomonitoring with lichens tends to be lower cost than installing instruments, and there is a database of baseline "clean" lichen community composition in Forest Service plots. Lichen have a wide geographic range and can monitor air quality in locations not amenable to sensors or equipment, making them suitable for assessing relative air quality in a region.
However, you should be aware of the limitations and considerations of using lichens for air quality biomonitoring. As with all bioindicators, lichen composition and health are influenced by factors other than the parameter of interest, which in this case is air quality, so other environmental variables such as temperature, relative humidity, available substrates, elevation, and precipitation need to be collected and used to isolate the pollution signal. In addition, regulatory agencies in the US tend to be unfamiliar with lichen monitoring data. Thus, it is critical to clearly communicate monitoring design and/or to convert lichen data into pollutant concentration units familiar to regulators through co-location with instrumented monitors and calibration.
Currently, lichen are most useful as low-cost screening tools to identify pollution hotspots and prioritize placement of more expensive equipment.
Methods
Categories of Methods
Elemental Analysis | Community Analysis | Physiological Assessment | Transplant Study | |
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Description | Collect lichen samples for laboratory analysis to determine identifies and concentrations of elements of interest | Collect and compare information on richness, abundance, and presence/absence of indicator species over geographic space or time. | Analyze changes in lichen anatomy and photosynthetic ability of naturally occurring lichen or transplanted specimens in response to exposure to pollutants. Examples of parameters to measure include chlorophyll concentrations, chlorophyll fluorescence, cell membrane integrity, CO2 exchange capacity. | Transplanting healthy lichen to a test area and measuring physiological response and/or elemental accumulation. |
Expertise Required | ||||
Equipment | ||||
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Considerations |
Specific Methods
Community Analysis
Physiological Assessment
Elemental Analysis
Other Guidance for Study Design
Determining Lichen Species of Interest
Spatial Sampling
Converting Observations to Air Quality Indicators
Consulting Experts
Questions
Title | Author | Updated | Likes | Comments |
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How do I...do multivariate analysis on lichen testing? | @Ag8n | about 2 years ago | 0 | 3 |
Research notes
Title | Author | Updated | Likes | Comments |
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How do I...do multivariate analysis on lichen testing? | @Ag8n | about 2 years ago | 0 | 3 |
Research Paper: Correlating NDVI with Lichen Responses to Air Pollution | @fongvania | over 2 years ago | 3 | 25 |
Event Recap: Environmental Storytelling - Stories from the Field | @fongvania | over 2 years ago | 1 | 0 |
Activity: Lichens for Qualitative Air Quality Determination | @fongvania | about 3 years ago | 1 | 0 |
Activity: Learning to Spot Lichens and Mosses | @fongvania | over 2 years ago | 5 | 4 |
Rock Tripe Slab | @cfastie | about 6 years ago | 1 | 0 |
Wikis
Title | Updated | Version | Views | Likes | |
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Lichen for Air Quality Biomonitoring | about 2 years ago by fongvania | 12 | 259 | 1 |
Activities
Purpose | Category | Status | Author | Time | Difficulty | Replications |
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Activity: Learning to Spot Lichens and Mosses | observe | - | @fongvania | 1h | easy | 0 replications: Try it » |
Activity: Lichens for Qualitative Air Quality Determination | observe | - | @fongvania | - | easy | 0 replications: Try it » |
Activities should include a materials list, costs and a step-by-step guide to construction with photos. Learn what makes a good activity here.
Resources
Hands-On Learning