Influence of elevation and the associated variation of climate and vegetation on selected soil properties of tropical rainforests across a wide elevational gradient
•Tropical rainforest soils vary with elevation and associated climate and vegetation.•Soil nitrogen (N), potassium (K), organic carbon (SOC), pH and EC increase with elevation.•N, K, SOC and EC form a composite factor which explains 60% of overall soil variation.•The composite soil factor increases...
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| Published in: | Catena (Giessen) Vol. 237; p. 107823 |
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| Main Authors: | , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
Elsevier B.V
30-03-2024
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| Subjects: | |
| Online Access: | Get full text |
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| Summary: | •Tropical rainforest soils vary with elevation and associated climate and vegetation.•Soil nitrogen (N), potassium (K), organic carbon (SOC), pH and EC increase with elevation.•N, K, SOC and EC form a composite factor which explains 60% of overall soil variation.•The composite soil factor increases with decreasing temperature and rainfall.•The composite factor increases with decreasing tree basal area, biomass and diversity.
Soils of tropical rainforests are likely to show a high degree of heterogeneity to match the diversity of their vegetation. However, soils of tropical rainforest ecosystems are less well-investigated than their floristics. Our objective in this work was to quantify the variation of selected soil properties across a wide elevational gradient in tropical rainforests of Sri Lanka and to determine the influence of climate and vegetation on the observed soil variation. Soil properties were measured in lowland and montane rainforests from 117 to 2235 m above sea level at 0–15 and 15–30 cm depths. Total soil nitrogen (N), exchangeable potassium (K), organic carbon (SOC), electrical conductivity (EC) and pH showed significant linear increases with increasing elevation. Soil available phosphorus (P) showed a weak linear decrease with elevation. Three composite soil variables extracted by Factor Analysis explained 93 % of the observed soil variation. Factor 1, which explained 60 % of the total variation, had N, K, SOC and EC loading on it while Factors 2 (25 %) and 3 (8 %) had P and pH loading respectively on them. Multiple regression analysis against long-term (1970–2018) mean climate showed that temperature and rainfall had negative relationships with Factor 1 while the diurnal temperature range had a positive relationship. Factor 2 was positively influenced by temperature but was negatively influenced by rainfall. Total tree basal area, standing biomass and plot-level vegetation diversity had negative effects on Factors 1 and 2. Factor 3 was not influenced by climate or vegetation properties. These results are consistent with the hypothesis that the availability of highly mobile soil nutrients (N and K) and SOC across elevational gradients in tropical rainforests is determined by varying temperature and rainfall controlling the balance between nutrient release via mineralization and decomposition and nutrient removal via leaching and plant uptake. |
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| ISSN: | 0341-8162 1872-6887 |
| DOI: | 10.1016/j.catena.2024.107823 |