Mechanisms of Expansion for an Introduced Species of Cordgrass, Spartina densiflora, in Humboldt Bay, California

Cordgrass Biomass in Salt Marshes

“…ca. 0.06 m yr-1 for S. densiflora as reported by Nieva et al, 2005 andKittelson &Boyd, 1997 in European and North American salt marshes, respectively). This faster colonization of surrounded sediment by "guerrilla" species has as a result a lower density of biomass in the occupied space.…”

“…For example, S. densiflora invading European salt marshes displaces the native S. maritima at middle and high marshes but it seems to be displaced by small cordgrass at low salt marshes (Castillo et al, 2008b). In this sense, it has been described that the invasion of S. densiflora at North American salt marshes is limited by competition with native species (Kittelson & Boyd, 1997) and that S. patens competitively excludes S. alterniflora and forbs at New England salt marshes (Ewanchuk & Bertness, 2004). Cordgrass biomass is also affected by competition with other coastal plants as reported along the North-eastern coast of the United States where the reed Phragmites australis Cav.…”

“…Moreover, Spartina species with "phalanx" growth develop very dense tussocks with tall canopy and high above-and bellow-ground biomass, avoiding the colonization of native species, stopping the development of ecological succession during very long periods and representing strong competitors (Figueroa & Castellanos, 1988). In addition, some invasive cordgrasses usually show an abundant seed production and long distance dispersion by tidal water and currents (Kittelson & Boyd, 1997;Nieva et al, 2001a;Castillo et al, 2003;Nieva et al, 2005; for S. densiflora in European and North American salt marshes). Alien Spartina usually modify the abiotic environment during their invasion faster than native species.…”

Control and consequences of Spartina spp. invasions with focus upon San Francisco Bay

“…Wrack deposition from S. densiflora has been monitored in invasive populations in Humboldt Bay, CA (Kittelson and Boyd 1997) and Spain (Castillo et al 2008). Bare patches that were created by tidal deposition of S. densiflora wrack were colonized by lateral expansion of S. densiflora in Humboldt Baylateral spread of plants adjacent to or within bare patches increased 15-fold compared to those plants surrounded by S. densiflora.…”

Variação na altura e na abundância de colmos e estruturas reprodutivas em populações pioneiras e maduras de Spartina alterniflora Loisel. e S. densiflora Brongn. (Poaceae) do sul do Brasil

“…Maiores quantidades de nutrientes aceleram a perfilhação e o crescimento vertical das plantas e logo sua capacidade de modificar seu próprio hábitat (Bertness 1991. As moitas destas plantas tendem a crescer centrifugamente colonizando planos entremarés (Kittelson & Boyd 1997, Marangoni & Costa 2012, tornando-se mais altas no centro (Castellanos et al 1998, Hulzen et al 2007, Mendonça & Costa 2008. Consequentemente, ao longo da formação de uma marisma de Spartina, as características do crescimento vegetativo podem se alterar.…”