Artículo
Changes in traits of shrub canopies across an aridity gradient in northern Patagonia, Argentina
Fecha de publicación:
12/2010
Editorial:
Elsevier Gmbh, Urban & Fischer Verlag
Revista:
Basic and Applied Ecology
ISSN:
1439-1791
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
Low and highly variable precipitation pulses exert a strong selective pressure on plant traits and this might provide axes of ecological differentiation among plant species in arid ecosystems. We asked whether aridity contributes to maintain high diversity of species and morphotypes in shrub canopies. We selected eleven study sites evenly distributed across a 400-km transect in northern Patagonia, Argentina. Precipitation is low and highly variable within and between years but almost homogeneous across the transect (125-150. mm). Mean annual temperature varied, however, ranging from 8 °C (west) to 13.5 °C (east) creating a west-east gradient of aridity (aridity index from 3.7 to 7.3, respectively). Sheep grazing commenced in the early 1900s at a similar intensity across the transect. We recorded the richness and cover of shrubs by species and by morphotypes (drought deciduous tall shrubs, evergreen tall shrubs, medium shrubs, and dwarf shrubs), and further calculated the species and morphotype Shannon diversity index at each site. We assessed the presence of spiny leaves, leaf pubescence, thorny stems, and photosynthetic stems in shrub species of all morphotypes and collected green leaves of the dominant shrub species (more than 80% of the total shrub cover) to assess the leaf area, leaf mass per unit area, N-, lignin- and soluble phenolic-concentrations per species at each site. Richness and diversity of shrub species and morphotypes were positively associated with aridity. The richness and diversity of shrub species with pubescent leaves and thorny stems, and nitrogen concentration in green leaves of dominant shrubs increased with increasing aridity. We conclude that our findings on increased diversification in life history traits, species and morhotypes in shrub canopies with increasing aridity support the hypothesis that variability in aridity provides axes of ecological differentiation among shrub species facilitating their coexistence.
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Articulos(CCT-CENPAT)
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - CENPAT
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - CENPAT
Citación
Moreno, Laura; Bertiller, Monica Beatriz; Carrera, Analía Lorena; Changes in traits of shrub canopies across an aridity gradient in northern Patagonia, Argentina; Elsevier Gmbh, Urban & Fischer Verlag; Basic and Applied Ecology; 11; 8; 12-2010; 693-701
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