Distinctive seed dispersal and seed bank patterns of invasive African grasses favour their invasion in a neotropical savanna

Author(s)

Xavier, Rafael O. ^{[1, 2]} ; Christianini, Alexander V. ^[3] ; Pegler, Gabriela ^[4] ; Leite, Marcelo Boccia ^[5] ; Silva-Matos, Dalva M. ^[5]

Affiliation

^[1] Univ Estadual Campinas, Dept Biol Vegetal, Rua Monteiro Lobato 255, BR-13083862 Campinas, SP - Brazil

^[2] Univ Sao Paulo, Dept Ecol, Rua Matao 14, BR-05508090 Sao Paulo, SP - Brazil

^[3] Univ Fed Sao Carlos, Dept Ciencias Ambientais, Rodovia Joao Leme dos Santos, Km 110, BR-18052780 Sorocaba, SP - Brazil

^[4] Univ Sao Paulo, Dept Hidraul & Saneamento, Ave Joao Dagnone 1100, BR-13563120 Sao Carlos, SP - Brazil

^[5] Univ Fed Sao Carlos, Dept Hidrobiol, Rodovia Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: Oecologia; v. 196, n. 1 APR 2021.
• Web of Science Citations: 0

Abstract

High propagule availability compared to native species is often critical to invasion success, but it is unclear if this has contributed to invasions by African grasses in Neotropical savannas. We compared patterns of occurrence in the vegetation, seed rain and seed bank among African and native grasses in Cerrado sites in southeastern Brazil. In grasslands and savannas, we obtained the abundance of grasses in the vegetation, in the seed rain (monthly for one year) and in the seed bank (rainy and dry season), and assessed seed limitation and relationships among compartments. Invasive grasses showed low abundance in all compartments and high seed limitation in grasslands, where the seed bank and seed rain were dominated by small-seeded native grasses, but were at least as abundant as the natives in the seed bank and seed rain in savannas, mostly due to high abundance of Melinis minutiflora at these compartments. Native grasses dispersal occurred in the rainy season, whereas invasive grass dispersal occurred from mid rainy to mid dry season (Urochloa decumbens) and in the dry season (M. minutiflora). Melinis minutiflora showed a more persistent seed bank than U. decumbens and natives in savannas. Abundance of invasive and most of the native grasses in the vegetation was positively related to their abundance in the seed rain. Differences in seed production, the timing of seed dispersal and seed bank persistence compared to native grasses seem to favour invasive African grasses in the Cerrado, but this role may differ between grasslands and savannas. (AU)

• FAPESP's process: 11/21019-6 - Determinant factors to the dominance of African grasses in two tropical seasonally dry ecosystems
• Grantee: Rafael de Oliveira Xavier
• Support Opportunities: Scholarships in Brazil - Doctorate