Wildlife Australia - Spring 2017

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Mangroves occur around most of the Australian mainland, increasing in diversity along warmer, wetter

shorelines in the north. Avicennia and Rhizophora species dominate southern and northern shorelines

respectively. (A) Rhizophora stylosa flower. Photo: Steve and Alison Pearson. (B) Beach wrack, which

washes into mangrove stands, particularly Lyngbya majuscula from microalgal blooms, is often found

hanging from mangrove limbs and foliage or covering their breathing roots, preventing gaseous

exchange. Mangrove seedlings sometimes die as a result, but the long-term impact is relatively minor.

Photo: Norm Duke. (C) Lumnitzera racemosa flower. This species is rare in southerly locales. Photo:

Steve and Alison Pearson. (D) In the tropics, where mangroves grow prolifically, distinctly stilt-rooted

Rhizophora mangroves, with waxy bright-green leaves, reign. Photo: Norm Duke. (E) ‘Ecotone’ shift at

Luggage Point, Qld, showing mangrove retreat and saltmarsh expansion corresponding to longer term

decreases in rainfall. Sea level changes can ‘move’ vegetation within the tidal zone, depending on the

direction of sea level changes. Photo: Norm Duke. (F) Flowers of the grey mangrove (Avicennia marina)

Photo: Janis Laraine Cossil. (G) A ‘leaves on a string’ experiment (p. 32) reveals that leaves are tucked

away in crab burrows, where they break down and nourish the ecosystem. Photo: Norm Duke. (H) Tiny

mangrove crabs help this ecosystem function by ‘recycling’ fallen mangrove leaves. Photo: Norm Duke.

ECOLOGICA

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