Sergio Piraino

Your research on forest resilience to atmospheric and edaphic drought is very important for understanding how climate change impacts ecosystems. The difference between these two types of drought (atmospheric and edaphic) can have various effects on plant growth and productivity, as well as on the overall resilience of forest ecosystems. Below are some theoretical frameworks and suggestions for assessing and comparing the differential effects of these droughts:

1. Concept of Atmospheric and Edaphic Drought

• Atmospheric drought refers to a deficit in precipitation and increased evaporation of water from the atmosphere. This type of drought affects the availability of water in the upper layers of the soil, but the soil may still have enough water deeper in the profile.
• Edaphic drought represents a water deficit in the soil itself, often resulting from prolonged low soil moisture. This type of drought can lead to a significant reduction in water availability for plants, as water is not even available in deeper layers.

2. Theoretical Frameworks for Assessing and Comparing Effects

In your research, you can use various approaches based on plant physiology and water dynamics in ecosystems.

a. Experimental Approaches

• Capillary uptake models and soil water dynamics: These models can show how water moves from atmospheric sources (precipitation and evaporation) to different layers of soil and assess how deeply water remains available for plants. Different models, such as SWAT (Soil and Water Assessment Tool), can calculate the effects of atmospheric and edaphic droughts on forest ecosystems.

b. Physiological Plant Responses

• Plants exposed to atmospheric drought often show increased evaporation and reduced photosynthetic capacity, but if they have access to water from deeper soil layers, they may recover more quickly. An example of this is deep roots, which allow plants to retain moisture from deeper soil layers during periods of reduced precipitation.
• In the case of edaphic drought, plants are subject to more extensive soil desiccation, which can lead to clinical drought conditions, where tissue damage occurs and overall growth processes are reduced.

c. Indicators of Drought Resistance

• Root water uptake efficiency and physiological adaptations such as changes in water use efficiency (the ratio between transpiration and photosynthesis) can be useful indicators for both types of drought.
• Carbon dioxide and water balance dynamics as a way to assess drought effects on plants: this includes measuring the partial vapor pressure inside leaves and the ratio between photosynthesis and transpiration rates.

3. Comparison of Effects on Forest Ecosystems

To compare the effects of atmospheric and edaphic drought, it may be useful to consider factors such as:

• Plant species: Some forest species (e.g., deciduous species) may be more sensitive to atmospheric drought, while evergreen trees with deep root systems may be more susceptible to edaphic drought.
• Forest composition: Differences in species and fauna can influence drought dynamics, as certain species may be more resistant to specific types of drought.
• Seasonal changes and climatic factors: The duration and intensity of drought during the period can affect the assessment of comparative atmospheric and edaphic drought effects.

4. Use of Indices and Methods

• Water deficit and drought indices: You can use various climatic and ecosystem indices, such as the Standardized Precipitation Index (SPI) for atmospheric drought or the Soil Moisture Index (SMI) for edaphic drought.
• Climate change models can help you assess how future changes in atmospheric and edaphic conditions might affect forest resilience.

The assessment and comparison of atmospheric and edaphic drought effects can be based on physiological, ecosystem, and climate models, as well as indicators such as root adaptation, water balance, and plant responses to different types of drought. The transition from one type of drought to another and its impact on different forest types requires careful analysis at multiple levels to obtain accurate and applicable results.

Dear Dragan,

thank you very much for your thorough answer!

Your research focus is critical given the increasing prevalence of droughts under climate change. Below are some suggestions for theoretical frameworks and evidence to assess and compare the differential effects of atmospheric and edaphic droughts:

Theoretical Frameworks:

Empirical Evidence:

Suggested Readings

• Books:
  • "Plant Physiological Ecology" by Hans Lambers et al. – Includes chapters on plant-water relations and drought responses.
  • "Forests, Water, and People in the Humid Tropics" (Cambridge Studies in Applied Ecology).
• Key Papers:
  • Allen, C. D., et al. (2015). "On the causes and consequences of global forest dieback under drought." Ecology Letters.
  • Anderegg, W. R. L., et al. (2019). "Hydraulic diversity buffers forests from climate change." Nature Climate Change.