Does habitat structure matter? Spatially explicit population modelling of an Iberian gypsum endemic

    Authors

    P. F. Quintana-Ascencio; I. Caballero; J. M. Olano; A. Escudero;M. J. Albert

    Abbreviated Journal Title

    Popul. Ecol.

    Keywords

    Autocorrelation; Cellular automata; Demography; Grazing; Helianthemum; squamatum; Microhabitat heterogeneity; SEMIARID CENTRAL SPAIN; SEED BANK; HELIANTHEMUM-SQUAMATUM; PLANT-COMMUNITIES; MEDITERRANEAN ECOSYSTEM; DESERT PLANTS; SOIL CRUSTS; DYNAMICS; PATTERNS; SHRUB; Ecology

    Abstract

    Habitat heterogeneity may influence plant demography because conditions for survival, growth, and reproduction vary within a species' range. We assessed the role of microhabitat spatial structure on the demography of Helianthemum squamatum, a shrubby gypsum specialist endemic to the Iberian Peninsula. We evaluated the demographic effect of microhabitat spatial variation using an approach that combined cellular automata with matrix population models, and included environmental and demographic stochasticty. We collected data on seed bank (2003-2005), seedling emergence (2003-2006), and adult survivorship (2004-2007) for H. squamatum in two independent blocks with different grazing intensity in BelinchA(3)n (Cuenca, Spain). We built spatial scenarios for each block based on field data of cover and spatial pattern of four microhabitats: lichenic crust, litter, H. squamatum, and shrub. Seedling survivorship was affected by year, block, and microhabitat, with individuals emerging under conspecifics having the highest survival rate and on litter the lowest in both blocks, whereas the effect of crust and other shrubs differed across blocks. Our models indicated population increase in the block with low grazing, but population decline in the block with intense grazing. We hypothesize that higher pressure of livestock grazing and trampling leads to a shift in relative microhabitat suitability for crust and shrub. This potential effect of grazing on spatial demographic variation opens interesting questions for future research. We emphasize the importance of considering microhabitat spatial structure when evaluating management and conservation strategies.

    Journal Title

    Population Ecology

    Volume

    51

    Issue/Number

    2

    Publication Date

    1-1-2009

    Document Type

    Article

    Language

    English

    First Page

    317

    Last Page

    328

    WOS Identifier

    WOS:000264328900011

    ISSN

    1438-3896

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