11 Impact of Climate Change on Fungi
Climate change is altering global ecosystems at an alarming rate, and fungi, as key players in these ecosystems, are facing unprecedented challenges and opportunities. This article will delve into the multifaceted impacts of climate change on fungi and provide practical coping strategies for field collectors.
Over the past century, the Earth's average surface temperature has risen by approximately 1°C, but more worryingly, the rate of warming is accelerating. According to the latest report from the Intergovernmental Panel on Climate Change (IPCC), by the end of this century, the global average temperature could be 1.5 to 4.8°C higher than pre-industrial levels.
- Polar regions are warming two to three times faster than the global average
- Warming is more pronounced in high-latitude regions of the Northern Hemisphere
- Urban areas are warming more significantly due to the heat island effect
In my collection records, the collection season in northern Minnesota has extended by about 12 days over the past two decades, while unprecedented fungal species have appeared at high-altitude collection sites in Arizona.
Global average precipitation has increased slightly, but regional differences are extreme. Some regions have become wetter, while others have experienced prolonged droughts.
- Precipitation distribution has become more uneven
- Frequency of extreme rainfall events has increased
- Duration of drought periods has lengthened
- Snowfall has decreased, while rainfall has increased
In California, multi-year droughts have led to a decline of over 70% in the yield of the prized *Boletus edulis*, while in the Pacific Northwest, exceptionally wet springs have brought record yields of chanterelles.
Extreme weather events such as heatwaves, droughts, floods, and wildfires have become more frequent and intense. These events have direct and profound impacts on fungal communities.
"When planning collection trips, consider not only the traditional season but also the impact of recent extreme weather events. The year following a wildfire might be a bumper year for certain species, like morels." - John Smith, Former President of the Pacific Fungi Association
In temperature-limited regions, initial warming may promote fungal growth. Fungal metabolic rates accelerate with rising temperatures, enzyme activity increases, and growth cycles shorten. However, once the optimal temperature range is exceeded, heat stress can lead to slowed growth or even cessation.
Temperature is a key trigger for fruiting body formation. The optimal temperature ranges for many species are changing:
- Spring species generally appear earlier
- Autumn species emergence times have become unstable
- Some species may cease fruiting entirely within their traditional distribution ranges
In Michigan, the traditional emergence time for morels was early May, but they now frequently begin appearing in mid-April. This change requires collectors to adjust their collection schedules.
Fungal growth requires specific humidity conditions. Drought can cause mycelium to enter dormancy or die, while overly wet conditions may lead to hypoxia.
- During drought seasons, prioritize searching north-facing slopes and areas near water sources
- The 3-7 day window after rain is the optimal collection period
- Use a soil moisture meter to help determine the best collection timing
- Digital Thermohygrometer: Measures micro-environmental conditions
- Soil Moisture Probe: Assesses subsurface conditions
- Portable Weather Station: Records environmental data at collection sites
Although fungi do not directly utilize CO₂ for photosynthesis, rising atmospheric CO₂ concentrations indirectly affect fungi by influencing their plant hosts.
In environments with elevated CO₂ concentrations, the abundance of mycorrhizal fungi sometimes increases, but this response is highly dependent on soil nutrient status, particularly nitrogen availability.
Long-term monitoring data show that the emergence time of spring fungi has advanced by an average of 1-2 weeks, while the emergence of autumn fungi has become unstable. In some regions, the overall collection season has lengthened, but interannual variability has significantly increased.
Sixty years of monitoring data from the British Mycological Society show that the emergence time of common edible fungi has advanced by an average of 2.3 days per decade. Similar trends have been observed in North America.
- Do not adhere rigidly to traditional collection dates
- Pay attention to local soil temperature and moisture conditions
- Establish your own phenological observation records
Many fungal species are migrating toward higher latitudes in the Northern Hemisphere and higher altitudes. However, this migration is constrained by several factors:
- Mycorrhizal fungi depend on specific tree species distributions
- Spore dispersal distance limitations
- Habitat fragmentation impedes migration
As species distributions change, consider exploring new collection areas:
- Expand to higher altitude areas
- Focus on climate refuge areas (e.g., north-facing slopes, canyon bottoms)
- Record the distribution of newly emerging species
- **Benefiting Species**: Heat-tolerant species, drought-tolerant species, broadly adaptable species
- **Threatened Species**: Cold-adapted species, high-humidity dependent species, ecological specialists
In some regions, the immigration of new species may temporarily increase local diversity, but in the long term, functional diversity may decrease as specialists are replaced by generalists.
The symbiotic relationship between mycorrhizal fungi and trees faces challenges under climate change stress:
- Trees under drought stress have a greater need for mycorrhizal assistance
- But mycorrhizal fungi themselves are also under climatic stress
- Symbiotic efficiency may decrease
Under drought conditions, the carbon cost for mycorrhizal fungi to acquire water increases, leading to reduced net benefits for trees.
Warming generally accelerates decomposition processes, but under drought conditions, decomposition may be suppressed.
Accelerated decomposition leads to more CO₂ release, potentially forming a positive feedback loop that further exacerbates climate change.
Establishing personal observation records is key to understanding the local impacts of climate change:
- Collection date, time, and specific location
- Observed species and quantities
- Local weather conditions and recent weather history
- Soil temperature and moisture
- Condition of associated plants
- GPS-enabled smartphone
- Fungal identification applications
- Standardized recording forms
- Soil testing kit
Abandon fixed collection dates in favor of decisions based on current environmental conditions:
- Monitor soil temperature reaching species-specific thresholds
- Track rainfall events and timing
- Consider the impact of recent extreme weather
Develop multiple collection sites to spread risk:
- Sites at different elevation gradients
- Sites with different aspects and microenvironments
- Backup sites at greater distances
Avoid over-reliance on a single species:
- Learn to identify and utilize multiple edible fungi
- Understand the seasonal emergence patterns of different species
- Master the ecological requirements of different species
- Lightweight, breathable clothing adaptable to changing climatic conditions
- Waterproof, breathable backpacks and containers
- Precise navigation and recording tools
- Emergency communication devices
As climate patterns change, field risks increase:
- More frequent extreme weather events
- Changing fire risk conditions
- Emerging health risks (e.g., heat stress)
- Follow scientific collection limits
- Use appropriate collection techniques to minimize damage to mycelium
- Avoid over-collection in fragile ecosystems
- Participate in habitat restoration projects
Transform personal observations into scientific data:
- Participate in fungal monitoring projects
- Share observations on platforms like iNaturalist
- Assist research institutions in data collection
Support the protection of areas with climate adaptation potential:
- Protected areas encompassing elevation gradients
- Ecological corridor construction
- Microclimate diversity protection
- Reduce personal carbon footprint
- Support climate-friendly policies
- Participate in forest protection projects
The impacts of climate change on fungi are complex and multifaceted, but several trends are clear: phenological changes are occurring, species distributions are adjusting, and ecosystem functions face reorganization. As field collectors and natural observers, we are on the front lines of documenting these changes.
1. Start Systematic Recording - Establish a personal observation log to record local fungal responses to climate change
2. Adjust Collection Strategies - Base collection plans on actual environmental conditions rather than traditional calendars
3. Expand Knowledge Scope - Learn to identify newly emerging species and understand changing distribution patterns
4. Participate in Conservation Actions - Support habitat protection and climate mitigation measures
5. Share Experience and Data - Contribute observation data through citizen science platforms
6. Advocate for Policy Change - Support science-based environmental protection and climate policies
The changes you observe in the forest are not random occurrences - they are specific manifestations of global climate change at the local scale. Every record, every observation, every responsible collection decision is an important component of our response to this global challenge. As people with deep connections to the fungal world, we not only have the privilege of enjoying nature's bounty but also the responsibility to protect this delicate, changing world.
Keep observing, keep recording, keep acting - for the future of fungi, and for our own future.
*This article is based on the latest scientific research and thirty years of personal field experience, but fungal responses to climate change are highly regional and species-specific. It is recommended to adjust specific practices based on local conditions and the latest research.*