Aquatic Plants Report Card

Aquatic Plants

Macroinvertebrates

Black Bream

Waterbirds

Fish Kills

Water Quality

Aquatic plants are critical to the Vasse Wonnerup wetlands providing food and habitat, oxygenating the water, using nutrients, and stabilising sediments. Aquatic plants including macrophytes (seagrasses and submerged plants) and macroalgae (seaweeds and filamentous algae) were monitored in spring across four regions in the wetlands. Percentage Volume Index (PVI) of key species and ratio of macrophytes to macroalgae were used to develop indicators for each region following methodology developed by Murdoch University.

Aquatic Plants Summary 2022 Across Regions

Upper Vasse Estuary

B

58%

16%

Lower Vasse Estuary

B

54%

15%

Upper Wonnerup Estuary

B

12%

43%

Lower Wonnerup Estuary

B

43%

26%

MACROPHYTES

Ruppia megacarpa
Ruppia polycarpa
Stuckenia pectinata
Althenia cylindrocarpa

CHAROPHYTES

Lamprothamnium macropogon

MACROALGAE

Ulva
Rhizoclonium
Cladophora

1 Plant = 1-10% Mean PVI

Key Findings

Healthy macrophyte communities were present across the Vasse-Wonnerup wetlands with very high density of key species, despite moderate growth of macroalgae.
The Vasse Estuary had the greatest density of macroalgae, mostly Ulva.

High key species density on the upper Vasse was related to growth of Ruppia megacarpa and Ruppia polycarpa.
The Wonnerup Estuary had a healthy plant community with greater density of the charophyte Lamprothamnium macropogon.