MODERN AND HISTORICAL VARIATION IN AQUATIC MACROPHYTE COVER OF BILLABONGS ASSOCIATED WITH CATCHMENT DEVELOPMENT

摘要

Visual estimates of macrophyte cover in Murray and Ovens River billabongs were unrelated to farming and regulation activities but were positively related to the ratio of Chydoridae to totalCladocera in assemblages of skeletal remains from surface sediments. This ratio(/100CHYD)was thus used as a surrogate for macrophyte cover in a palaeoecological analysis. Valued of /100 CHYD were lower in sediments deposited after European settlement that in the pre-settlement parts of sediment cores from three relatively large deep billabongs, and two moderately-sized in the littoral macrophyte zone was fond in historical records from the two smallest billabongs, although the records were of poorer quality.