Does over-dominance of &lt;i&gt;Bambusa&lt;/i&gt; &lt;i&gt;bambos&lt;/i&gt; (L.) Voss. alter abundance and richness of Arbuscular Mycorrhizal fungal community in forests?

Tharanga Wijewickrama,Fathima Mafaziya,H. M. S. P. Madawala

doi:10.4038/cjs.v48i1.7588

Abstract

Some areas under the Tropical Moist Evergreen Forests (TMEF), the major forest type in the Intermediate Zone of Sri Lanka, are heavily dominated by a native bamboo species, Bambusa bambos (L.) Voss. altering the hierarchical status and structure. The study evaluated whether the over-abundance of B. bambos has modified the arbuscular mycorrhizal fungal (AMF) communities in soil. Soil samples collected from bamboo-dominated (BM) and non-bamboo (NB) forest patches in three different locations viz., Moragolla, Maragomuwa and Galboda, were enumerated for AMF spores using wet sieving and decanting method. A total of 1,577 and 898 AMF spores were documented from BM and NB forest patches, respectively. A total of 14 different morphotypes belonged to the genera, Glomus, Scutellospora, Gigaspora and Acaulospora, were identified. Glomus was the dominant genus in all study sites, while Acaulospora the least. The mean abundance and richness of AMF spores were higher in BM than in NB, with the most notable difference observed at Maragomuwa. These site-specific variations may perhaps due to the differences in vegetation characteristics, edaphic properties and disturbance regimes. However, the community structure of AMF showed no conspicuous modifications due to the over-abundance of B. bambos. The findings reiterated the general understanding that any changes to the above-ground vegetation may incur impacts on the AMF. However, AMF community structure shows resilience to influences imposed by the dominance of a single species.

Highlights

In recent years, soil microbial communities and their participation in ecosystem functions received renewed interests from scientists
A total of 14 morphotypes of Arbuscular mycorrhizal fungi (AMF) spores were recorded in all study sites, belonging to four families, Glomeraceae, Scutellosporaceae, Gigasporaceae and Acaulosporaceae
Half of the AMF spores were belonged to the family of Glomeraceae in both BM (45 %) and NB (50 %) forests, while the lowest contribution was recorded from Acaulosporaceae (7.5 and 6.6% in BM and NB, respectively)

Summary

Introduction

Soil microbial communities and their participation in ecosystem functions received renewed interests from scientists. The invasion-driven changes to the vegetation have in turn altered the below-ground parameters including the soil microbiota (Vila et al, 2011; Rodriguez et al, 2015; Yang et al, 2016), perhaps through changes in litter quality and quantity, soil moisture and temperature, root exudates and nutrient turnover rates (Ehrenfeld, 2010).The studies show that the invasion of exotic bamboos sustain significant impacts on the structure and diversity of soil microbial communities, with more emphasis on bacteria (Chang and Chiu, 2015; Lin et al, 2014) than that of fungi (Xu et al, 2015; Li et al, 2017). AMF show facilitative effect on the invasion success of some exotic plants (Edirisinghe and Madawala, 2017) while others show that AMF could transform habitats to resist invasion (Yang et al, 2016; Zhang et al, 2010), through positive/negative plant-AMF feedback

Methods

Results

Conclusion