Low soil phosphorus and high symbiotic fungal richness inhibits plant aboveground biomass in fragmented forests in China

TL;DR

In fragmented forests of China, low soil phosphorus and high fungal richness reduce plant biomass, showing how environmental factors shape plant growth.

Contribution

The study identifies soil phosphorus and fungal richness as key drivers of plant biomass in fragmented island ecosystems.

Findings

Plant aboveground biomass is positively correlated with soil phosphorus.

High richness of symbiotic fungi negatively correlates with plant biomass.

Low soil phosphorus and high fungal richness reduce biomass on small islands.

Abstract

Habitat fragmentation is a major threat to biodiversity, and it usually leads to microclimate variations. Habitat quality (e.g. nutrients and moisture) and fungal symbioses play important roles in plant growth and ecosystem productivity. However, the impact of habitat fragmentation on plant aboveground biomass (AGB) is unclear. We examined the soil nutrients, rhizosphere fungal richness, and the AGB of 10 woody plant species on 10 islands of the same age but varying in size and isolation, in a land-bridge island system of subtropical China. Here we show that island size, soil nutrients, and fungal symbioses are key factors driving plant growth patterns in a fragmented island system. Plant AGB is positively correlated with soil phosphorus (P) but negatively correlated with richness of symbiotic fungi, suggesting that P content is more impactful than fungal symbiosis on plant growth in subtropical fragmented forests. Across all islands, low soil P and high symbiotic fungal richness lead to decreased plant AGB on small islands. These findings highlight the critical role of environmental filtering in shaping plant development within island fragments.

Habitat fragmentation reduces plant aboveground biomass on small islands via reduced soil phosphorus content and increased symbiotic fungal richness, highlighting the critical role of environmental filtering in fragmented forests.

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