Long-Term Effects of Tidal Exclusion on Salt Marsh Plain Species at Estero de Punta Banda, Baja California

Abstract

Disturbance is an important factor influencing plant species composition and diversity. We addressed changes in plant composition and soil characteristics in Estero de Punta Banda, Baja California, Mexico following 22 years of disturbance by tidal exclusion. Currently, sediments in the non-tidal site are dry, 26±1% moisture, and hypersaline, 143±12; while those at the tidal marsh are wet, 36.2±1% moisture, with 40.3±2.6 salinity. The nontidal site has lost seven species including annuals, shortand long-lived perennials, ephemerals, and parasites. Current dominants are the perennials Batis maritima and Sarcocornia pacifica. Average species richness at the nontidal site is 4.4±0.32 vs.10±0.18 species per square meter at the tidal site. Average species diversity index is lower at the diked area. The general biodiversity loss that results from tidal exclusion in arid estuaries, contrasts with the species-rich communities that develop in diked humid-climate estuaries.

Assessment of Blue Carbon Storage by Baja California (Mexico) Tidal Wetlands and Evidence for Wetland Stability in the Face of Anthropogenic and Climatic Impacts

“…Further, despite the presence of legal protections that have prohibited mangrove destruction, mangroves in México are being deforested for coastal development at a rate of 1.1% per annum [ 72 ]. Most of the lagoons under study here have been threatened with wetland destruction over past decades; this includes threats from the proposed expansion of commercial salt production to Laguna San Ignacio [ 73 ], and the wetland diking that occurred in 1983 for industrial development in Estero Punta Banda [ 74 , 75 , 76 ]. Baja California’s tidal wetlands have survived in a pristine state because of their isolation, but since the 1970s and the construction of the transpeninsular Highway, they are much more vulnerable to loss from development.…”

Salt Marsh-Upland Ecotones in Central California: Vulnerability to Invasions and Anthropogenic Stressors

“…While no other studies have focused on tidal restriction effects on the ecotone, investigations from other regions have demonstrated effects of tidal restriction on salt marsh vegetation composition and zonation (Roman et al 1984;de Leeuw et al 1994;Burdick et al 1997;Sun et al 2003), and in southern California and Baja California, tidal restriction has been shown to decrease marsh plant richness (Zedler et al 2001;Ibarra-Obando et al 2010).…”