Effects of fire on biodiversity and ecosystem multifunctionality: field observations and meta-analysis

Ondertitel:field observations and meta-analysis

Korte inhoud:Fire, as an extreme ecological disturbance, not only affects biodiversity but also poses a persistent threat to ecosystem functions and services. With global climate change and increasing human activities, fire disturbance is reshaping ecosystems. Understanding its multifaceted impacts, especially the post-fire recovery of biodiversity and ecosystem functions, is now a key focus in ecology. Fire is not merely a disruptor of biological community structures, it also profoundly influences ecological processes including energy flow, material cycles, and species interactions. For instance, severe fire events can lead to drastic changes in vegetation and soil communities, directly affecting key ecosystem functions, such as soil quality, carbon storage, and water regulation. However, to date, research exploring the relationship between biodiversity and ecosystem multifunctionality under fire disturbance remains scarce. This study combines field observations and meta-analysis comprehensively assess the impact of fire on biodiversity, ecosystem multifunctionality, and their relationship. Field experiment was conducted across four sites (1, 5, 9, 27 years post-fire) in Pinus yunnanensis forests located on the Central Yunnan Plateau, focusing on the diversity of soil bacteria, fungi, protists, and nematodes, alongside 38 functional ecosystem indicators. Additionally, a global meta-analysis was performed using 2284 biodiversity-related observation pairs from 275 studies and 17087 ecosystem function-related observation pairs from 787 studies. The main findings are as follows: 1. Field study conducted in Pinus yunnanensis forests on the Central Yunnan Plateau indicated that the responses of soil bacteria, fungi, protists, and nematodes to fire were influenced by soil depth and time since fire. The biodiversity of all trophic groups (except for protists) in the 0-10 cm soil layer declined 5 years post-fire. These negative effects gradually diminished nine years post-fire, and by 27 years post-fire, soil biodiversity significantly increased (except for nematodes). In the 10-20 cm soil layer, the richness of bacteria, fungi, and protists increased 1 year post-fire. However, five years later, their richness declined by 16.7%, 13.9%, and 45.3%, respectively. After 9 to 27 years of recovery, all trophic groups not only recovered to their pre-fire richness but exceeded it. 2. We sampled from Pinus yunnanensis forests on the Central Yunnan Plateau, measured 38 individual functions and calculated ecosystem multifunctionality using the averaging approach, multiple threshold approach, and single-function approach. Our findings showed that the impact of fire on ecosystem multifunctionality varied with soil depth and time since fire. In the 0-10 cm soil layer, ecosystem multifunctionality declined by 179%, 191%, and 116% at 1, 5, and 9 years post-fire, respectively. However, after 27 years of recovery, ecosystem multifunctionality exhibited a positive trend. In the 10-20 cm soil layer, ecosystem multifunctionality declined more sharply within the first 1 to 5 years after the fire compared to the 0-10 cm layer but gradually recovered to pre-fire level. Additionally, results from all three approaches consistently revealed that fire strengthened the relationship between soil biodiversity and ecosystem multifunctionality. 3. A global meta-analysis from 275 publications demonstrated that, overall, fire reduced biodiversity of multiple trophic groups, including tree diversity, soil microbial diversity, soil mesofauna diversity, and soil multidiversity. The impact of fire on biodiversity was jointly regulated by fire type, fire severity, and post-fire recovery time. Specifically, compared to prescribed burning, wildfires had a more significant effect on tree diversity, herbaceous diversity, plant multidiversity, and soil microfauna diversity. Wildfires negatively impacted tree diversity and microfauna diversity but positively influenced herbaceous diversity and plant multidiversity. Moderate to high-severity fires had more pronounced negative effects on woody diversity, total plant diversity, soil microbial diversity, soil mesofauna diversity, soil macrofauna diversity, plant multidiversity, and soil multidiversity than low-severity fires. During post-fire recovery, tree diversity and soil multidiversity decreased within 10 years, while herbaceous diversity and plant multidiversity increased. Between 10 and 20 years, herbaceous diversity and plant multidiversity declined. After more than 20 years of recovery, total plant diversity increased, but plant multidiversity and soil microbial diversity decreased. 4. A global meta-analysis from 787 articles revealed that fire generally reduced multiple ecosystem functions, including water regulation, climate regulation, plant production, soil biotic biomass, carbon storage, soil organic matter decomposition, and ecosystem multifunctionality. The response of ecosystem functions to fire was influenced by fire type, fire severity, and post-fire recovery time. Compared to prescribed fires, wildfires had more significant negative effects on climate regulation, plant production, soil biotic biomass, nutrient cycling, and soil organic matter decomposition, whereas prescribed fires had a greater negative impact on carbon storage and ecosystem multifunctionality. Under high-severity fire conditions, water regulation function significantly declined. During post-fire recovery, the negative effects of fire on plant production, soil biotic biomass, and carbon storage were stronger within the first 10 years, while the negative impact on climate regulation became more pronounced after more than 20 years. Nutrient cycling initially exhibited a positive response (< 10 years) but turned negative in the middle and late recovery stages (> 10 years). At the global scale, a positive correlation was observed between the responses of biodiversity and ecosystem functions to fire. However, plant diversity showed a saturation curve, whereas soil biodiversity exhibited a non-saturation pattern. 5. Based on our global meta-analysis data, variance partitioning analysis further revealed that changes in biodiversity and ecosystem functions could be effectively explained by soil pH, climate, fire characteristics, and spatial coordinates. Mean annual precipitation and fire severity were the primary explanatory factors for plant diversity, whereas soil biodiversity responses to fire were closely associated with mean annual temperature and latitude. Soil pH was the best predictor for climate regulation, soil biotic biomass, carbon storage, and soil organic matter decomposition. Mean annual precipitation was the key driver of nutrient cycling and ecosystem multifunctionality, while fire severity and recovery time were the most important explanatory factors for water regulation and plant production, respectively. Spearman correlation analysis further indicated that plant diversity response to fire was positively correlated with soil pH but negatively correlated with mean annual temperature. Soil biodiversity was positively correlated with mean annual precipitation, mean annual temperature, and soil pH. The responses of ecosystem functions showed an overall negative correlation with soil pH. This study explored the long-term effects of fire on soil biodiversity and ecosystem multifunctionality in Pinus yunnanensis forests and conducted a global-scale meta-analysis to reveal overall patterns of fire impacts on biodiversity and ecosystem functions. The findings demonstrate that fire affects soil biodiversity and ecosystem functions through multiple factors, particularly soil depth, fire type, fire severity, and post-fire recovery time. Moreover, the study elucidates the potential mechanisms through which fire strengthens the relationship between biodiversity and ecosystem multifunctionality. These insights contribute to a better understanding of the multidimensional impacts of fire on ecosystem structure and function, providing a scientific basis for formulating post-fire recovery strategies. Additionally, with the increasing frequency and intensity of fires driven by global climate change, fire has become a major challenge for ecosystems. This work provides critical theoretical support for further investigations into the ecological role of fire in the context of global change.

Jaar van publicatie:2025

Trefwoorden:Biology

Toegankelijkheid:Closed