The absence of significant influence of soil properties on the structure of fungal communities across land-use types in Mau Mount (Kedowa, Kenya)
Biological communities differ over time and in space, and in the forest these communities often vary according to forest cover, tree species and deforested areas cultivated during many years. These land-uses can have significant impacts on soil conditions and microbial communities are likely to respond to these changes. However, such responses are poorly characterized as few studies have examined how specific changes in edaphic do, or do not, influence the composition of soil bacterial and fungal communities across land-use types. The present study aimed to determine whether forest vegetation has a greater influence on both soil characteristics and soil fungal community structure based on denaturing gradient gel electrophoresis (DGGE) analysis of 30 top soil (0-10 cm) samples harvested in May 2006 in the Mau Mount, in Kedowa areas (Kenya). Five different land-uses were investigated: the natural forest; a 41-years old Pinus canariensis plantation installed after the clearance of the forest, a rotation: natural forest-cypress (Cupressus lusitanica) plantation (within 34 years)-crops (within 3 years)- natural vegetation since 2002, a rotation: natural forest- Pinus canariensis plantation (within 34 years)-crops (3 years)-natural vegetation since 2002 and finally a cypress (Cupressus lusitanica) plantation. Our results showed that natural forest had significantly higher organic C content, total N content and P available content. Total microbial biomass is also significantly higher in the soil of natural forest than in soil of Pinus canariensis plantation and natural regeneration of the previous forest plantation. In despite of such huge soil characteristic differences fungal DGGE analysis using 28S rRNA genes was strongly related to the land-use with specific clusters significantly differing each other. By running a Pearson correlation analysis of the corresponding Shannon index values, our results indicated that only total P, Mn and Fe contents showed a positive and significant (p<0.05) correlation with the diversity of the total fungal communities. These results might suggest that the fungal communities were related to land-use more than soil characteristics. Thus we suggest that indicators based on the fungal communities might not be suitable as microbial indicators for soil quality. (Texte intégral)
| Main Authors: | , , , , |
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| Format: | conference_item biblioteca |
| Language: | eng |
| Published: |
s.n.
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| Subjects: | P34 - Biologie du sol, P33 - Chimie et physique du sol, K01 - Foresterie - Considérations générales, K10 - Production forestière, |
| Online Access: | http://agritrop.cirad.fr/578986/ http://agritrop.cirad.fr/578986/3/578986.pdf |
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| Summary: | Biological communities differ over time and in space, and in the forest these communities often vary according to forest cover, tree species and deforested areas cultivated during many years. These land-uses can have significant impacts on soil conditions and microbial communities are likely to respond to these changes. However, such responses are poorly characterized as few studies have examined how specific changes in edaphic do, or do not, influence the composition of soil bacterial and fungal communities across land-use types. The present study aimed to determine whether forest vegetation has a greater influence on both soil characteristics and soil fungal community structure based on denaturing gradient gel electrophoresis (DGGE) analysis of 30 top soil (0-10 cm) samples harvested in May 2006 in the Mau Mount, in Kedowa areas (Kenya). Five different land-uses were investigated: the natural forest; a 41-years old Pinus canariensis plantation installed after the clearance of the forest, a rotation: natural forest-cypress (Cupressus lusitanica) plantation (within 34 years)-crops (within 3 years)- natural vegetation since 2002, a rotation: natural forest- Pinus canariensis plantation (within 34 years)-crops (3 years)-natural vegetation since 2002 and finally a cypress (Cupressus lusitanica) plantation. Our results showed that natural forest had significantly higher organic C content, total N content and P available content. Total microbial biomass is also significantly higher in the soil of natural forest than in soil of Pinus canariensis plantation and natural regeneration of the previous forest plantation. In despite of such huge soil characteristic differences fungal DGGE analysis using 28S rRNA genes was strongly related to the land-use with specific clusters significantly differing each other. By running a Pearson correlation analysis of the corresponding Shannon index values, our results indicated that only total P, Mn and Fe contents showed a positive and significant (p<0.05) correlation with the diversity of the total fungal communities. These results might suggest that the fungal communities were related to land-use more than soil characteristics. Thus we suggest that indicators based on the fungal communities might not be suitable as microbial indicators for soil quality. (Texte intégral) |
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