Title

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

Authors

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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