Soil N, P, and C dynamics of upland and seasonally flooded forests of the Brazilian Pantanal

Global Ecology and Conservation

卷:12

Osvaldo Borges Pinto, Jr¹  Edna Carneiro¹  George L. Vourlitis²  Cloe S. Hentz²  Jose de Souza Nogueira³ 

[1] Departamento de Ciências Ambientais, Programa de Pós-Graduação Em Ciências Ambientais, Universidade de Cuiabá, Cuiabá Mato Grosso, 78060-900, Brazil;

[2] Department of Biological Sciences, California State University, San Marcos, CA 92096, USA;

[3] Instituto de Física, Programa de Pós-Graduação em Física Ambiental, Universidade Federal de Mato Grosso, Cuiabá Mato Grosso, 78060-900, Brazil;

关键词: Cerrado;    Hyperseasonal savanna;    Net mineralization;    Nutrient cycling;    Pantanal;   

DOI  :  10.1016/j.gecco.2017.11.004

来源: DOAJ

【 摘 要 】

Seasonal variations in cerrado nutrient availability and mineralization are poorly understood, especially for “hyperseasonal” cerrado, which experiences both flooding and drought over an annual cycle. Here we quantified seasonal variations in soil ammonium (NH4+), phosphorus (P), and organic C (SOC) concentration and net mineralization in upland and seasonally flooded cerrado forests of the Brazilian Pantanal, and hypothesized that NH4+, P, and SOC concentrations and net mineralization would decline under flooding and increase during the dry season as soil becomes unsaturated. We found that C and nutrient concentrations and mineralization were significantly affected by seasonal variations in hydrology; however, differences between flooded and upland forests varied over time and were not always related to flooding. Soil extractable P, but not net mineralization, was approximately 10-times higher in the upland forest, while the flooded forest had higher extractable NH4+ concentration than the upland forest under both flooded and drained conditions. Soil C concentration was significantly higher in the upland forest even though C mineralization was similar for both forests. Thus, despite the large seasonal and spatial variations in hydrology, the effects of flooding depended on the particular response variable studied and the season. While a limited survey of the literature indicates that forests exposed to intermittent flooding had on average higher concentrations of extractable NH4+ and P, the upland and hyperseasonal forests studied here were richer in extractable NH4+ (upland and flooded) and P (upland) compared to other upland and hyperseasonal forests and woodlands. Given that the forests studied here shared nearly a third of the total tree species and had similar physiognomy, these results suggest that nutrient controls on cerrado structural diversity may be similar in upland and hyperseasonal cerrado.

【 授权许可】

Unknown