01601naa a2200265 a 450000100080000000500110000800800410001902000180006010000200007824500810009826000090017952007570018865300250094565300280097065300220099865300340102070000190105470000170107370000170109070000200110770000260112770000170115370000160117077301490118610875852012-11-19       2011    bl uuuu     u00u1 u    #d  a97898723175221 aGENRO, T. C. M.  aStructural traits in natural grassland grazed by heifers in Southern Brazil.  c2011  aSpecies forming tussocks are common in complex pastoral systems like the grasslands of the Pampas biome. A detailed knowledge of tussock structure is the key to understand the relationships between plants and animals. The abundance and defoliation patterns of caespitose species can be influenced by management that uses animals as the principal agents of structural changes driven by selective grazing (Laca et al., 2001). Thus, factors that determine selection or avoidance of tussocks by cattle can determine the structure and dynamics of tussocks. We evaluated tussock botanical composition and physical structure as factors to explain patterns of defoliation of the upper stratum in natural pastures with and without fertilization and overseeding.  aAndropogon lateralis  aErianthus angustifolius  aGrazing intensity  aNatural grassland improvement1 aFEDRIGO, J. K.1 aPINTO, C. E.1 aNEVES, F. P.1 aTRINDADE, J. K.1 aCARVALHO, C. P. C. F.1 aNABINGER, C.1 aLACA, E. A.  tIn: INTERNATIONAL GRASSLAND CONGRESS, 9., 2011, Rosário. Proceedings... Rosário: Instituto Nacional de Tecnología Agropecuaria, 2011. p. 402.