Short- and Long-Term Vegetative Propagation of Two Spartina Species on a Salt Marsh in Southern Brazil

作者：Marangoni Juliano Cesar^*; Bonifacio Costa Cesar Serra

来源：Estuaries and Coasts, 2012, 35(3): 763-773.

DOI：10.1007/s12237-011-9474-7

• Salt marsh
• Spartina alterniflora
• Spartina densiflora
• Vegetative propagation
• Lateral spread
• El Nino
• Flooding
• Regression

Spartina alterniflora and Spartina densiflora are native salt marsh plants from the Atlantic coast; their habitats in Patos Lagoon estuary (southern Brazil) are characterized by a microtidal regime (< 0.5 m) and, during El Nio events, high estuarine water levels and prolonged flooding due to elevated freshwater discharge from a 200,000-km(2) watershed. During and between El Nio events, the vegetative propagation of these two Spartina species in the largest estuary of southern Brazil (Patos Lagoon) was evaluated by monitoring transplanted plants for 10 years (short-term study) and interpreting aerial photos of natural stands for 56 years (long-term study). During the short-term study, S. alterniflora quickly occupied mud flats (up to 208 cm year(-1)) by elongation of rhizomes, whereas S. densiflora showed a modest lateral spread (up to 13 cm year(-1)) and generated dense circular-shaped stands. However, moderate and strong El Nio events can promote excessive flooding and positive anomalies in the estuarine water level that reduce the lateral spread and competitive ability of S. densiflora. During the long-term study, natural stands of S. alterniflora and S. densiflora had steady lateral spread rates of 152 and 5.2 cm year(-1), respectively, over mud flats. In the microtidal marshes of the southwest Atlantic, the continuous long-term lateral expansion of both Spartina species embodies periods of intense flooding stress (moderate and strong El Nios), when there is a decrease of vegetative propagation and less stressful low water periods of fast spread over mud flats (non-El Nio periods and weak intensity El Nios).

• 出版日期2012-5