Southern Research Station

Title: Spatial relationships among species, above-ground biomass, N, and P in degraded grasslands in Ordus Plateau, northwestern China

Author: Cheng, X.; An, S.; chen, J.; Li, B.; Liu, Y.; Liu, S.

Date: 2007

Source: Journal of Arid Environments, Vol. 68: 652-667

Description: We chose five communities, representing a mild to severe gradient of grassland desertification in a semi-arid area of Ordos Plateau, northwestern China, to explore the spatial relationships among plant species, above-ground biomass (AGB), and plant nutrients (N and P). Community 1 (Cl) was dominated by Stipa bungeana; community 2 (C2) by a mix of S and the shrub Artemisia ordosica; community 3 (C3) by a ordosica, community 4 (C4) by a mix of Cynachum komarovii and C. komorovii, and community 5 (C5) by C. komorovii. Quantitative methods, including geostatistics, were used to compare community composition, structure, and indicators of ecosystem funciton (i.2. AGB, plant N and P.) in five 16-m² plots. the highest AGB, plant nitrogen (N) and plant phosphorus (p) were found in lightly degraded community C2. With increasing desertification effects from C3 to C5, the AGB, N, and P decreased significantly while plant density remained unchanged. The spatial variations of AGB were higher in shrub-dominated communities (C1 and C5) than in grass-dominated communities (C2-C4). Strong spatial relationships were detected within and among the communities, with stronger relationships between AGB and density than between AGB and species richness. Spatial patterns of plant N and P were different from those of AGB, reflecting different N and P contents of individual plants and different species that can redistribute soil resources in these communities. the AGB was positively correlated with soil nutrients (TOC, TN, TP, and IN), except for soil AP. We concluded that several specific aspects of ecosystem properties were directly associated with the conversion of the grass and shrub "functional types" in these degraded grasslands.

Keywords: spatial heterogeneity, desert vegetation, plant nutrients, disturbed prairie, geostatistics

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Citation

Cheng, X.; An, S.; chen, J.; Li, B.; Liu, Y.; Liu, S.  2007.  Spatial relationships among species, above-ground biomass, N, and P in degraded grasslands in Ordus Plateau, northwestern China.   Journal of Arid Environments, Vol. 68: 652-667