Mixed mangroves

Long description

Low open shrubland to closed forest of a mixture of mangrove species forming a variety of associations, depending on frequency of inundation and freshwater influence. Avicennia marina or Rhizophora spp. are the most dominant species but Aegiceras corniculatum and Ceriops spp. can also form forests. Other relatively common species include Excoecaria agallocha, Bruguiera spp., Lumnitzera racemosa and Alchornea ilicifolia. Occurs on Quaternary estuarine deposits on intertidal flats which are often dissected by tidal streams. Soils are usually deep saline clays[8]. Usually occurs along the landward fringe where no dominant mangrove genera is distinguishable.

Mangroves are not a taxonomically unified group, but rather an ecological group that arose through convergent evolution and includes several different families. They are characterised by trees that are adapted to tolerate tidal inundation.

Special values

Mangrove communities provide a wide variety of services, including:

• physical coastal protection from erosion and flooding
• sediment trapping
• primary production
• nutrient processing
• food, shelter and breeding areas for a wide range of fauna including birds, water mouse (landward margin), fish, crustaceans and other invertebrates[6][2][10][4].

The landward margin of mangrove forests can provide nesting habitat for the water mouse. These areas are typically dominated by Sporobolus virginicus and sedges south of Eurimbula, and Bruigiera gymnorhiza north of Eurimbula, due to the high tidal range.

Avicennia pneumatophores provide structural habitat for a range of fish, crustaceans and molluscs. The water mouse has also been observed hunting in pneumatophores, and nesting in the landward margin of mangrove forests. The prop roots and frequent tidal inundation of Rhizophora forests provide particularly good nursery habitat for fish, crustaceans and molluscs, many of recreational and commercial importance. Fiddler crabs (Uca coarctata and Uca dussumieri) and molluscs (e.g. whelks) can be particularly abundant in Rhizophora forests. The interface of mangroves and an estuary often provide the best nursery habitat in association with the high abundance of snags and/or prop roots[9]. Dense growth of the red algae Catenella nipae on mangrove prop roots and pneumatophores provides food for recreationally important herbivorous fishes[3].

Diagnostic attributes

Inundation 'Intertidal – Lower low', 'Intertidal – Mid low', 'Intertidal – Upper low', 'Intertidal – Low undifferentiated', 'Intertidal – Lower medium', 'Intertidal – Upper-medium', 'Intertidal – Medium undifferentiated', 'Intertidal – High', 'Intertidal – Undifferentiated', 'Intertidal – High undifferentiated' although mangroves usually occur at mean sea level and above

Structural macrobiota 'Mangroves – mixed'

Qualifiers

No qualifiers mapped however Period and Trend are relevant as mangrove extent can be influenced by sea level rise.

Distribution

Worldwide there are about 65 recognised species of mangrove plants. Of which, 34 species, with three hybrids, are known to occur in Queensland[6]. In Queensland, mangroves grow in tropical and temperate areas, diversity generally increases towards the equator. For example, there are 31 species of mangrove plants recorded in the Daintree region, eight species in south-east Queensland, and two species in southern temperate Australia. The north-east coast of Australia was close to the centre of mangrove origin and dispersal. The climate is similar to that under which they first evolved, and the sheltered shallow waters of numerous estuaries are ideal for growth[7][5].

Large mangrove and saltmarsh ecosystems in Queensland include:

• Princess Charlotte Bay
• Hinchinbrook Island
• Bowling Green Bay
• Broadsound and Shoalwater Bay
• the Fitzroy River estuary[5].

The following relates to distribution of this ecosystem type within the Central Queensland mapping area:

• Particularly important fisheries habitat from Round Hill Head to Tin Can Inlet, in term of productivity, includes the Kolan, Elliott, Burrum, Mary and Susan rivers, Baffle and Kauri creeks, Great Sandy Strait and Tin Can Inlet. The smaller Broadwater, Littabella and Beelbi creeks are also important in terms of habitat diversity and connectivity with the larger nearby systems (Baffle Creek, and the Kolan and Burrum rivers)[1].
• The most extensive mangrove forests from Tin Can Inlet to Round Hill Head are (in decreasing extent) closed forests dominated by Rhizophora spp., Avicennia marina, Avicennia/Ceriops spp., Ceriops spp., Aegiceras corniculatum, open Avicennia marina, open Avicennia/Ceriops spp., closed Rhizophora/Aegiceras spp., closed mixed, closed Rhizophora/Avicennia spp., open Bruguiera spp. and open Ceriops spp. Avicennia marina or Ceriops spp. typically dominate higher energy areas from Tin Can Inlet to Round Hill Head, with mixed communities landward. In low energy waters from Tin Can Inlet to Round Hill Head, there are typically closed Avicennia/Ceriops forests landward of closed Rhizophora forests[1].
• The most extensive mangrove forests in Port Curtis are (in decreasing extent) closed forests of Rhizophora spp., Avicennia/Ceriops spp., mixed mangroves, Rhizophora/Avicennia spp., Ceriops spp., Avicennia marina, Aegiceras corniculatum, open Avicennia marina, closed Aegiceras/Rhizophora spp., open Ceriops spp., closed Aegiceras/Avicennia spp. and other minor types (less than 20 hectares). The seaward edge is typically closed Rhizophora forest, with a narrow band of Avicennia/Ceriops spp. landward, and then extensive saltpans without vegetation. Succulents and grasses grow on some saltpans, which are not as hypersaline. Along the landward margin of the saltpan, there may be a narrow band of Ceriops spp. with or without Lumnitzera racemosa and/or Excoecaria agallocha. In association with freshwater, closed Rhizophora/Avicennia forests may grow along waterways, Aegiceras may grow on accreting banks of meandering waterways, and mixed communities with Xylocarpus moluccensis may grow in the very upstream extent[2].
• Other mangrove species recorded in Port Curtis and from Tin Can Inlet to Round Hill Creek include Acanthus ilicifolius, Acrostichum speciosum, Aegialitis annulata, Crinum pedunculatum, Hibiscus tiliaceus, Osbornia octodonta, Xylocarpus granatum and Xylocarpus moluccenis. This area is the transition between subtropical and tropical species and includes the southern-most distribution of A. annulata, O. octodonta and X. granatum[1][2].
• In Bioregion 12, regional ecosystem Mangrove shrubland to low, closed forest occurs on Quaternary estuarine deposits and can be dominated by:
  • Aegiceras corniculatum low closed forest above MSL in areas occasionally subject to freshwater influence (12.1.3a)
  • Avicennia marina subsp. australasica shrubland to low closed forest, usually along the seaward margin (12.1.3b)
  • Bruguiera gymnorhiza shrubland to low closed forest, usually at the upper tidal limit of rivers and subject to freshwater influence (12.1.3c). In the Great Sandy Strait and on the landward shores of K'gari (Fraser Island), Bruguiera gymnorhiza is associated with areas of groundwater seepage and is found next to freshwater wetlands (e.g. Melaleuca dominated) (Maria Zann, 2019 pers. comm.)
  • Ceriops australis shrubland to low closed forest, usually on the landward/saltpan margin (12.1.3d)
  • Rhizophora stylosa shrubland to low closed forest, usually large forests extending from the seaward margin in muddier areas (12.1.3e)
  • estuarine water bodies often with groundwater connectivity (12.1.3f)
  • mangrove dieback area leaving bare soil or ponding (12.1.3g)[8].

Comments

Other relevant attributes include Consolidation, Energy and Sediment texture as mangroves typically occur on unconsolidated muds and fine sediments in low energy environments.

Freshwater source and volume are relevant as the mix of mangrove species may change in areas subject to groundwater and/or freshwater influence.

Additional Information

Mangroves - WetlandInfo

Common mangroves - Department of Agriculture and Fisheries

MangroveWatch

Mangrove Challenge

Mangrove community dynamics - OzCoasts

Mangroves and associated communities of Moreton Bay - WetlandInfo

Serious Dieback of Mangroves around Mackay - University of Queensland

References

1. ^ a b c Bruinsma, C & Danaher, K (2001), Queensland Coastal Wetland Resources: Round Hill Head to Tin Can Inlet.. [online], vol. QI99081, Department of Primary Industries, Queensland Government., Brisbane. Available at: http://era.daf.qld.gov.au/id/eprint/3545/.
2. ^ a b c Danaher, K, Rasheed, M & Thomas, R (2005), The intertidal wetlands of Port Curtis, Department of Primary Industries and Fisheries.
3. ^ Davis, J, Pitt, K, Fry, B, Olds, A & Connolly, R (2014a), 'Seascape-scale trophic links for fish on inshore coral reefs', Coral Reefs. [online], vol. 33, no. 4, pp. 897-907. Available at: https://link.springer.com/article/10.1007/s00338-014-1196-4#aboutcontent.
4. ^ Duke, N (2006), Australia’s Mangroves: the authoritative guide to Australia’s mangrove plants, University of Queensland, Brisbane.
5. ^ a b Great Barrier Reef Marine Park Authority (GBRMPA) (2007), Great Barrier Reef (GBR) Features (Reef boundaries, QLD Mainland, Islands, Cays, Rocks and Dry Reefs) (GBRMPA) (metadata), eAtlas Data Catalogue AIMS, Townsville.
6. ^ a b Lovelock, C (1993), Field guide to the mangroves of Queensland, AIMS.
7. ^ Queensland Government (2019), Mangroves - WetlandInfo. [online] Available at: https://wetlandinfo.des.qld.gov.au/wetlands/ecology/components/flora/mangroves/.
8. ^ a b Queensland Herbarium & Environmental Protection Agency, B (2005), Regional Ecosystem Description Database (REDD). Version 5.0. [online], Environmental Protection Agency, Brisbane. Available at: https://apps.des.qld.gov.au/regional-ecosystems/.
9. ^ Sheaves, M (1996), 'Habitat-specific distributions of some fishes in a tropical estuary', Marine and Freshwater Research. [online], vol. 47, no. 6, p. 827. Available at: http://www.publish.csiro.au/?paper=MF9960827 [Accessed 23 April 2019].
10. ^ Sheaves, M (2005), 'Nature and consequences of biological connectivity in mangrove systems', Marine Ecology Progress Series. [online], vol. 302, pp. 293-305. Available at: http://www.int-res.com/abstracts/meps/v302/p293-305/ [Accessed 15 March 2019].

Last updated: 22 July 2019