Effects of nutrient loading and extreme rainfall events on coastal tallgrass prairies: Invasion intensity, vegetation responses, and carbon and nitrogen distribution

Global Change Biology
By: , and 

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Abstract

Soil fertility and precipitation are major factors regulating transitions from grasslands to forests. Biotic regulation may influence the effects of these abiotic drivers. In this study, we examined the effects of extreme rainfall events, anthropogenic nutrient loading and insect herbivory on the ability of Chinese tallow tree (Sapium sebiferum) to invade coastal prairie to determine how these factors may influence woody invasion of a grassland. We manipulated soil fertility (NPK addition) and simulated variation in frequency of extreme rainfall events in a three growing season, full factorial field experiment. Adding water to or pumping water out of plots simulated increased and decreased rainfall frequencies. We added Sapium seeds and seedlings to each plot and manipulated insect herbivory on transplanted Sapium seedlings with insecticide. We measured soil moisture, Sapium performance, vegetation mass, and carbon and nitrogen in vegetation and soils (0–10 cm deep, 10–20 cm deep). Fertilization increased Sapium invasion intensity by increasing seedling survival, height growth and biomass. Insect damage was low and insect suppression had little effect in all conditions. Recruitment of Sapium from seed was very low and independent of treatments. Vegetation mass was increased by fertilization in both rainfall treatments but not in the ambient moisture treatment. The amount of carbon and nitrogen in plants was increased by fertilization, especially in modified moisture plots. Soil carbon and nitrogen were independent of all treatments. These results suggest that coastal tallgrass prairies are more likely to be impacted by nutrient loading, in terms of invasion severity and nutrient cycling, than by changes in the frequency of extreme rainfall events.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Effects of nutrient loading and extreme rainfall events on coastal tallgrass prairies: Invasion intensity, vegetation responses, and carbon and nitrogen distribution
Series title Global Change Biology
DOI 10.1111/j.1365-2486.2007.01425.x
Volume 13
Issue 10
Year Published 2007
Language English
Publisher Wiley
Contributing office(s) National Wetlands Research Center, Wetland and Aquatic Research Center
Description 9 p.
First page 2184
Last page 2192
Country United States
State Texas
Other Geospatial University of Houston Coastal Center