River Water Salinity and the Distribution of Mangrove Species Along Several Rivers in North Queensland

Abstract

It is well recognized that salinity is one of the major factors influencing the vegetation of mangrove swamps. Nonetheless, knowledge of the limits of salinity tolerance is limited to a relatively few species. Accordingly, observations were undertaken of the distributions of a number of mangrove species in a set of tidal rivers in northern Queensland. River water salinity measurements were used as the frame of reference to the observations. To the extent that generalizations are possible, tolerance of or adaptation to sea water appeared to lie in a series as follows: Rhizophora stylosa; R . apiculata; Sonneratia alba; Ceriops tagal > Aegiceras corniculatum; Bruguiera parviflora > Excoecaria agallocha; Rhizophora mucronata > Acrostichum sp.; Heritiera littoralis; Nypa fruticans > Barringtonia sp.; Bruguiera sexangula; Sonneratia caseolaris; (Hibiscus tiliaceus).