IFEVA   02662
INSTITUTO DE INVESTIGACIONES FISIOLOGICAS Y ECOLOGICAS VINCULADAS A LA AGRICULTURA
Unidad Ejecutora - UE
artículos
Título:
Ecosystem changes associated with grazing removal in sub-humid grasslands of South America
Autor/es:
ALTESOR, A. I., G. PIÑEIRO, F. LEZAMA, R. D. JACKSON, M. SARASOLA Y J. M. PARUELO
Revista:
JOURNAL OF VEGETATION SCIENCE
Referencias:
Año: 2006 p. 323 - 332
ISSN:
1100-9233
Resumen:
Abstract
Question:What are the changes in vegetation structure,soil
attributes and mesofauna associated with grazing in mesic
grasslands?
Location:Southern Campos of the Río de la Plata grasslands,
in south-central Uruguay.
Methods:We surveyed seven continuously grazed and
ungrazed paired plots.Plant and litter cover were recorded on
three 5-m interception lines placed parallel to the fence in each
plot.We extracted soil fauna from a 10 cm deep composite
sample and analysed the oribatids.Soil attributes included
bulk density,water content,organic carbon (in particulate and
mineral associated organic matter)and nitrogen content and
root biomass at different depths.Changes in floristic,Plant
Functional Types and mesofauna composition were analysed
by Non-metric Multidimensional Scaling.
Results:Species number was lower in ungrazed than in grazed
plots.Of 105 species in grazed plots only three were exotics.
Shrub and litter cover were significantly higher inside the
exclosures,while the cover of Cyperaceae-Juncaceae was lower.
Grazing treatments differed significantly in plant and oribatid
species composition..Grazing exclusion significantly reduced
soil bulk density and increased soil water content.Carbon
content in particulate organic matter was lower in the upper soil
of ungrazed sites,but deeper in the profile,grazing exclosures
had 8%more carbon in the mineral associated organic matter.
Conclusions:Our results generally agree with previous studies
but deviate from the results of previous analyses in (1)the
increase of shrub cover in ungrazed sites;(2)the redistribution
of the soil organic carbon in the profile and (3)the low invasibility
of the prairies regardless of grazing regime.
Keywords:Oribatide;Plant Functional Type;Soil attribute;
Species richness;Uruguay.
Abbreviations:BMRPP =Blocked multi-response permuta-
tion procedures;INDVAL =Indicative values ;MAOM =
Mineral associated organic matter;NMDS =Non-metric multi
dimensional scaling;POM =Particulate organic matter.
Nomenclature:Cabrera &Zardini (1978