DOI: 10.1111/gcb.13066
论文题名: Exotic grasses and nitrate enrichment alter soil carbon cycling along an urban-rural tropical forest gradient
作者: Cusack D.F. ; Lee J.K. ; Mccleery T.L. ; Lecroy C.S.
刊名: Global Change Biology
ISSN: 13541013
出版年: 2015
卷: 21, 期: 12 起始页码: 4481
结束页码: 4496
语种: 英语
英文关键词: Dissolved organic carbon
; Enzyme activities
; Invasive species
; NAGase
; Nitrogen deposition
; Non-native species
; Phosphatase
; Seasonality
; Secondary rain forest
; Soil moisture
; β-glucosidase
Scopus关键词: carbon cycle
; dissolved organic carbon
; enzyme activity
; grass
; nitrate
; nitrogen
; phosphatase
; rainforest
; seasonality
; soil carbon
; soil moisture
; tropical forest
; Poaceae
; nitric acid derivative
; soil
; carbon cycle
; chemistry
; city
; forest
; grassland
; growth, development and aging
; introduced species
; nitrogen cycle
; Poaceae
; Puerto Rico
; soil
; tropic climate
; Carbon Cycle
; Cities
; Forests
; Grassland
; Introduced Species
; Nitrates
; Nitrogen Cycle
; Poaceae
; Puerto Rico
; Soil
; Tropical Climate
英文摘要: Urban areas are expanding rapidly in tropical regions, with potential to alter ecosystem dynamics. In particular, exotic grasses and atmospheric nitrogen (N) deposition simultaneously affect tropical urbanized landscapes, with unknown effects on properties like soil carbon (C) storage. We hypothesized that (H1) soil nitrate (NO3-) is elevated nearer to the urban core, reflecting N deposition gradients. (H2) Exotic grasslands have elevated soil NO3- and decreased soil C relative to secondary forests, with higher N promoting decomposer activity. (H3) Exotic grasslands have greater seasonality in soil NO3- vs. secondary forests, due to higher sensitivity of grassland soil moisture to rainfall. We predicted that NO3- would be positively related to dissolved organic C (DOC) production via changes in decomposer activity. We measured six paired grassland/secondary forest sites along a tropical urban-to-rural gradient during the three dominant seasons (hurricane, dry, and early wet). We found that (1) soil NO3- was generally elevated nearer to the urban core, with particularly clear spatial trends for grasslands. (2) Exotic grasslands had lower soil C than secondary forests, which was related to elevated decomposer enzyme activities and soil respiration. Unexpectedly, soil NO3- was negatively related to enzyme activities, and was lower in grasslands than forests. (3) Grasslands had greater soil NO3- seasonality vs. forests, but this was not strongly linked to shifts in soil moisture or DOC. Our results suggest that exotic grasses in tropical regions are likely to drastically reduce soil C storage, but that N deposition may have an opposite effect via suppression of enzyme activities. However, soil NO3- accumulation here was higher in urban forests than grasslands, potentially related to of aboveground N interception. Net urban effects on C storage across tropical landscapes will likely vary depending on the mosaic of grass cover, rates of N deposition, and responses by local decomposer communities. © 2015 John Wiley & Sons Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/61720
Appears in Collections: 影响、适应和脆弱性
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作者单位: Department of Geography, University of California, 1255 Bunche Hall Box 951524, Los Angeles, CA, United States
Recommended Citation:
Cusack D.F.,Lee J.K.,Mccleery T.L.,et al. Exotic grasses and nitrate enrichment alter soil carbon cycling along an urban-rural tropical forest gradient[J]. Global Change Biology,2015-01-01,21(12)