Woody plant encroachment of grasslands: a comparison of terrestrial and wetland settings. Issue 3 (10th November 2014)

• Record Type: Journal Article
• Authors: Saintilan, Neil; Rogers, Kerrylee
• Is Part Of: New phytologist. Volume 205:Issue 3(2015)
• Page Start: 1062
• Page End: 1070
• Publication Date: 2014-11-10
• Subjects: atmospheric CO2 -- encroachment -- fire -- saltmarsh -- shrub; Botany -- Periodicals; 580
• DOI: 10.1111/nph.13147
• Languages: English
• ISSNs: 0028-646X

Abstract

Summary: A global trend of woody plant encroachment of terrestrial grasslands is co‐incident with woody plant encroachment of wetland in freshwater and saline intertidal settings. There are several arguments for considering tree encroachment of wetlands in the context of woody shrub encroachment of grassland biomes. In both cases, delimitation of woody shrubs at regional scales is set by temperature thresholds for poleward extent, and by aridity within temperature limits. Latitudinal expansion has been observed for terrestrial woody shrubs and mangroves, following recent warming, but most expansion and thickening has been due to the occupation of previously water‐limited grassland/saltmarsh environments. Increases in atmospheric CO2, may facilitate the recruitment of trees in terrestrial and wetland settings. Improved water relations, a mechanism that would predict higher soil moisture in grasslands and saltmarshes, and also an enhanced capacity to survive arid conditions, reinforces local mechanisms of change. The expansion of woody shrubs and mangroves provides a negative feedback on elevated atmospheric CO2 by increasing carbon sequestration in grassland and saltmarsh, and is a significant carbon sink globally. These broad‐scale vegetation shifts may represent a new stable state, reinforced by positive feedbacks between global change drivers and endogenic mechanisms of persistence in the landscape.