Windows of opportunity for Prosopis velutina seedling establishment and encroachment in a semiarid grassland

Victor Resco de Dios, Jake F. Weltzin, Wei Sun, Travis E. Huxman, David G. Williams

    Research output: Contribution to journalArticle

    9 Citations (Scopus)

    Abstract

    Large increases in the density of woody plants in former grasslands have been documented globally over the past two centuries. Prosopis velutina (velvet mesquite) has recently expanded on over 38 million ha in the grasslands of the American southwest. Mesquite establishment and expansion is potentially influenced by competitive interactions with grasses, particle size distribution (texture) of soil and changes in the amount and/or seasonality of precipitation, amongst other factors. To investigate the relative importance of precipitation seasonality, grass competition, and soil texture on mesquite seedling and establishment, we experimentally manipulated seasonality of precipitation across 72 1.5 m × 1.7 m plots that we planted with two grasses from contrasting functional groups (or left unvegetated) across two highly contrasting soil textures within a semi-desert grassland in Arizona, USA, wherein we followed the demography of 8640 planted mesquite seeds between 2002 and 2006. Up to 70% of the variance in seedling emergence was explained by soil water content, and seedling mortality was more dependent on summer than on winter precipitation. Mortality of less drought tolerant grasses after drought in coarse textured soils created conditions most favorable for seedling establishment, whereas lower rates of seedling establishment were observed in finer textured soils or in plots dominated by more drought tolerant grasses. We conclude that mesquite encroachment is episodic, based on discontinuous patterns of seedling establishment, favored on coarse textured soils and associated with unique conditions of high summer water availability when precipitation is not limiting and when competition from grasses is lowered.
    Original languageEnglish
    Number of pages8
    JournalPerspectives in Plant Ecology\, Evolution and Systematics
    Publication statusPublished - 2012

    Open Access - Access Right Statement

    Copyright © 2012 Perspectives in Plant Ecology, Evolution and Systematics

    Keywords

    • plant interactions
    • precipitation
    • savannah
    • soil texture
    • water manipulation
    • woody plant encroachment

    Fingerprint

    Dive into the research topics of 'Windows of opportunity for Prosopis velutina seedling establishment and encroachment in a semiarid grassland'. Together they form a unique fingerprint.

    Cite this