Tolerance of riverine plants to flooding and exposure indicated by water regime

Abstract

Selected water regime indices are used to describe the tolerances to flooding and exposure of littoral and floodplain plants of the River Murray, South Australia. The cover and abundance of 26 perennial species were surveyed at 12 sites along a reach where water levels were influenced by weir operations. Six indices were measured: days when water depths were ≥0, 0–20, 20–60 and ≥200 cm; days when plants were exposed to ≥100 cm of water; and days of longest exposure to water. Ordinations of plant abundances were correlated with the frequency of flooding to 0–20 and 20–60 cm, and exposure to ≥100 cm. Five species clusters were apparent, these being common floodplain species (e.g. Muehlenbeckia florulenta), uncommon floodplain species (e.g. Eleocharis acuta), species from the infrequently flooded littoral (e.g. Bolboschoenus caldwellii), species from the permanently flooded littoral (e.g. Vallisneria americana) and widespread, common species tolerant to flooding and exposure (11 species, including Phragmites australis, Cyperus gymnocaulos and Bolboschoenus medianus). Half of the 26 species occurred in at least four of seven regimes suggested by cluster analysis of water regime indices, thus indicating a broad tolerance to flooding and exposure. Preferred water regimes are summarised using minimum and maximum values and quartiles for the six indices, and similarities between preferences are illustrated by a model based on minimum spanning tree techniques. Copyright © 1999 John Wiley & Sons, Ltd.

EFFECT OF SOIL SATURATION ON DEVELOPMENT AND15N-NITRATE UPTAKE EFFICIENCY OF TWO WARM SEASON GRASSES EMERGING FROM DORMANCY

“…Bermudagrass is reportedly capable of tolerating prolonged periods of complete submersion (Blanch et al, 1999). Therefore, it is not surprising that bermudagrass performed well under saturated conditions for the 72-day period of this study.…”

“…turfgrasses are widely planted in the southeastern U.S. While there are few published data, bermudagrass is considered to possess tolerance to a wide range of conditions including submergence (Rhoades, 1964;Blanch et al, 1999), while centipedegrass may lack tolerance to saturated soils (Horn, 1966;Beard, 1973;Turgeon, 2002).…”

Effects of hydrological variation on the aquatic plant community in a floodplain palustrine wetland of southern Brazil

“…The water-level variation can affect the establishment, growth, and survival of aquatic plants (Blanch et al 1999;Seabloom et al 2001). The variation in wetland vegetation is driven by changes in aquatic macrophyte populations whose response to hydrological oscillation can occur in several ways (van der Valk 2005).…”

Water-level fluctuations in North American prairie wetlands

“…Because hydrologists are not concerned directly with when such extreme events occur, standard hydrological statistics are often not relevant to ecologists because they are not linked to ecologically important phenomena like seed dispersal, seed germination, seedling growth and survival, etc. Duration of flooding has been the most common hydrological statistic used to explain the distribution of species in wetlands (e.g., Nestler & Long, 1997;Toner & Keddy, 1997;Blanch et al, 1999). Richter et al (1996), however, suggested a series of hydrological statistics or 'Indicators of Hydrologic Alteration' that can be used to describe the hydrology of, and to assess hydrologic alterations to, aquatic ecosystems.…”