|Title||Soil characteristics, carbon stores, and nutrients distribution in eight forest types along an elevation gradient, eastern Puerto Rico|
|Publication Type||Book Chapter|
|Year of Publication||2013|
|Authors||Ping, CL, Michaelson, GJ, Stiles, CA, Grizelle González|
|Book Title||Ecological Bulletins|
|Series Title||Ecological Gradient Analyses in a Tropical Landscape|
Soil properties, carbon and nutrient distribution were studied along an elevation gradient covering eight distinctforest types in eastern Puerto Rico. The dominant soil forming parent materials are granodiorite saprolite and vol-canic rocks which exert a strong influence on the soil properties. Soils on middle to high elevations are very stronglyacidic with low base saturation (<20%) due to a strong leaching environments. Soils formed in lowlands, dry forestand coastal wetlands are moderately to weakly acidic with higher base saturation (>40%). Generally, organic carbon(OC), nitrogen (N) and nutrients accumulated in the surface horizons and decrease with depth. Soils formed in areasinfluenced by landslides or alluvium were the exception to this pattern. Soil OC and N stores follow the elevationgradient: from 26.7 kg OC m–2and 1.4 kg N m–2in soils of the colder and wetter mountain tops to 12.3 kg OCm–2and 1.0 kg N m–2in soils of the lower elevation dry forests. The C:N ratio decreased from 20 to 11 as elevationdecreased along the gradient. Landscape movement on uplands through landslides, slumps and fluvial/alluvial proc-esses has a significant effect on variation of C stores which must be considered when estimating C stores by landscapeunits. The coastal wetlands have exceptionally high OC stores (>90 kg m–2) due to their water-saturated and reducingenvironment. Soil OC content showed an inverse relation with soil bulk density and played a controlling role oncation exchange capacity (CEC) and nutrient distribution. Clay content has no effect on CEC. Elevation through itsinfluence on precipitation and temperature exerts strong influence in the quantity and quality of terrestrial OC stores,and the depth-distribution pattern of C, N and other nutrients.