Microbial determinants of soil quality in mixed larch and birch forests: network structure and keystone taxa abundances – Frontiers

Report on the Impact of Forest Stand Types on Soil Microbial Communities and Soil Quality

Introduction

This report presents findings from original research conducted at Hebei Agricultural University, Baoding, China, focusing on the influence of different forest stand types on soil microbial community characteristics and soil quality. The study aligns with the Sustainable Development Goals (SDGs), particularly SDG 15 (Life on Land) and SDG 13 (Climate Action), by exploring sustainable forest management practices that enhance soil health and ecosystem resilience.

Study Overview

The research investigated three typical forest types:

1. Larch (Larix principis-rupprechtii) forest (LF)
2. Birch (Betula platyphylla) forest (BF)
3. Mixed larch and birch forest (MF)

The objective was to assess soil properties, microbial community characteristics, and the complexity and stability of microbial co-occurrence networks across these forest stands.

Key Findings

Impact on Soil Quality and Nutrients

• Stand type significantly influenced soil quality indicators including soil organic carbon (SOC), total nitrogen (TN), available nitrogen (AN), available phosphorus (AP), and maximum water holding capacity (MWHC).
• Both MF and BF stands showed higher levels of these soil nutrients compared to LF stands.
• The Soil Quality Index (SQI) increased by 54.29% in MF stands and 48.57% in BF stands relative to LF stands.

Microbial Community Composition and Diversity

• Bacterial diversity, measured by the Shannon index, was lower in MF and BF stands.
• Fungal diversity was higher in MF and BF stands, with fungal communities being more sensitive to stand type variations than bacterial communities.

Microbial Network Complexity and Stability

• Mixed forest (MF) stands exhibited greater microbial network complexity and stability.
• There was a higher relative abundance of keystone bacterial and fungal taxa involved in nutrient cycling and transformation in MF stands.

Implications for Sustainable Development Goals (SDGs)

The study’s outcomes contribute to several SDGs by providing insights into sustainable forest ecosystem management:

• SDG 15: Life on Land – Enhancing soil microbial diversity and soil quality supports healthy forest ecosystems and biodiversity conservation.
• SDG 13: Climate Action – Improved soil nutrient cycling and carbon storage in mixed forests contribute to climate change mitigation.
• SDG 12: Responsible Consumption and Production – Sustainable forest management practices informed by microbial community dynamics promote efficient resource use.

Recommendations

1. Promote mixed-species forest plantations, particularly combining larch and birch, to enhance soil quality and microbial diversity.
2. Incorporate microbial network analysis into forest management to monitor ecosystem health and nutrient cycling efficiency.
3. Support further research on keystone microbial taxa to optimize nutrient transformation processes in forest soils.

Conclusion

This study highlights the critical role of forest stand composition in shaping soil microbial communities and improving soil quality. By emphasizing fungal diversity and microbial network stability, mixed larch and birch forests demonstrate enhanced soil nutrient utilization, which is essential for sustainable forest management. These findings provide valuable references for achieving SDGs related to ecosystem health, climate resilience, and sustainable land use.

Additional Information

• Keywords: Larix principis-rupprechtii, Betula platyphylla, Microbial Diversity, Network Complexity, Network Stability, Keystone Taxa
• Correspondence: Zhidong Zhang, Hebei Agricultural University, Baoding, China
• Publication: Frontiers in Plant Science, Volume 16, 2025, DOI: 10.3389/fpls.2025.1491038
• License: Creative Commons Attribution License (CC BY)

1. Sustainable Development Goals (SDGs) Addressed or Connected

1. SDG 15: Life on Land
   • The article focuses on forest soil microbial communities, soil quality, and nutrient cycling in plantation ecosystems, which are directly related to the sustainable management of forests and terrestrial ecosystems.
2. SDG 13: Climate Action
   • Improving soil quality and microbial diversity can enhance carbon sequestration (soil organic carbon), contributing to climate change mitigation.
3. SDG 2: Zero Hunger
   • Soil nutrient cycling and quality improvements support sustainable agriculture and food production by maintaining healthy soils.

2. Specific Targets Under Those SDGs Identified

1. SDG 15: Life on Land
   • Target 15.1: Ensure the conservation, restoration, and sustainable use of terrestrial and inland freshwater ecosystems and their services.
   • Target 15.2: Promote sustainable forest management to halt deforestation, restore degraded forests, and increase afforestation and reforestation.
2. SDG 13: Climate Action
   • Target 13.2: Integrate climate change measures into national policies, strategies, and planning, including enhancing carbon sinks such as forests and soils.
3. SDG 2: Zero Hunger
   • Target 2.4: Ensure sustainable food production systems and implement resilient agricultural practices that increase productivity and maintain ecosystems.

3. Indicators Mentioned or Implied to Measure Progress

1. Soil Quality Index (SQI)
   • Used to assess overall soil quality improvements in different forest stand types.
2. Soil Organic Carbon (SOC)
   • Indicator of soil carbon sequestration and soil health.
3. Total Nitrogen (TN), Available Nitrogen (AN), Available Phosphorus (AP)
   • Indicators of soil nutrient availability and fertility.
4. Microbial Diversity Indices (Bacterial and Fungal Shannon Index)
   • Measures of microbial community diversity, which relate to ecosystem function and resilience.
5. Network Complexity and Stability of Microbial Communities
   • Implied indicators of ecosystem health and nutrient cycling efficiency.
6. Relative Abundance of Keystone Microbial Taxa
   • Indicator of critical microbial functions related to nutrient cycling and transformation.

4. Table: SDGs, Targets and Indicators

Source: frontiersin.org