Ecological regime shifts in salinised wetland systems. I. Salinity thresholds for the loss of submerged macrophytes

Sim, L.L., Chambers, J.M. and Davis, J.A. (2006) Ecological regime shifts in salinised wetland systems. I. Salinity thresholds for the loss of submerged macrophytes. Hydrobiologia, 573 (1). pp. 89-107.

Abstract

This paper is the first in a pair investigating potential mechanisms for ecological regime change in salinising wetlands. In this first paper, we investigated some of the factors responsible for the formation and maintenance of a macrophyte-dominated ecological regime by studying the germination and flowering of four submerged macrophyte species common in saline Western Australian wetlands; Ruppia polycarpa R. Mason, Ruppia megacarpa R. Mason, Lamprothamnium macropogon (A. Braun) Ophel and L. cf. succinctum (A. Braun in Ascherson) Wood, and by following the survival of adult R. polycarpa as salinities were increased to a range of endpoints (6, 15, 45, 70 and 100 ppt). Increased salinity led to a decrease in the number of germinating plants, an increase in the time to emergence of germinating plants and a decrease in the number of inflorescences (or fertile plants) produced by R. polycarpa, L. macropogon and L. cf. succinctum. Germination of R. megacarpa was low, providing limited information with regard to salinity response. The survival of adult plants also decreased as salinity increased and was negatively affected by faster rates of salinity increase. The upper salinity limits for germination, within the 70 day experiment, were 40-50 ppt for R. polycarpa and L. cf. succinctum, and 30-40 ppt for L. macropogon. Survival of adult R. polycarpa also declined markedly at above 45 ppt.

Item Type:	Journal Article
Murdoch Affiliation(s):	School of Environmental Science
Publisher:	Kluwer Academic Publishers
Copyright:	© 2006 Springer.
URI:	http://researchrepository.murdoch.edu.au/id/eprint/11308

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