Patterns of polychaete recolonization in Queensland subtropical estuaries following severe flooding

Abstract

Quantitative sampling of macrobenthos and fouling organisms in the estuarine reaches of the Calliope River and Auckland Creek, Gladstone, Australia has been conducted since November 1974, and includes the recovery period (1974)(1975)(1976)(1977)(1978)(1979)(1980)(1981) following severe flooding (and flood-induced scouring) in December 1973/January 1974 . Changes in numbers of the 18 most abundant species of benthic polychaetes and one encrusting serpulid (Ficopomatus uschakovi) are examined. Numbers of F uschakovi settling on fouling panels showed a regular seasonal pattern, with a late summer maximum and a winter minimum throughout this period . The total numbers of individuals for all taxa in benthic samples followed a clear colonization pattern, with super-imposed seasonality ; plateau densities were reached five years after flooding . Total numbers of the 18 most abundant polychaetes showed a similar recolonizational pattern including the seasonal variation.Generally, those species of polychaetes with similar trophic strategies displayed similar patterns of abundance throughout the period : (i) The suspended detritus feeders (F uschakovi, Branchiomma sp ., Lysilla pacifica, Amaena trilobata and Terebellides stroemi) formed a constant proportion of the population ; (ii) Mobile surface detrital feeders (Glycera americana, Nephtys mesobranchia, Lumbrineris sp ., Sthenolepis sp. and Poecilochaetus serpens) initially formed a high proportion of the population which diminished with time ; (iii) The stationary surface detrital feeders (Magelona dakini, Paraprionospio sp ., Isolda pulchella and Pseudopolydora kempi) initially formed a low proportion which increased to a maximum four to five years after flooding and subsequently declined ; (iv) The sole surface deposit feeder examined (Leitoscoloplos normalis) had two peaks -in early 1975 and 1978 ; (v) The subsurface deposit feeders (Cossura sp., Sternaspis scutata, Euclymene sp . and Mediomastus sp.) initially formed a small proportion increasing continuously to become the most abundant group at the end of the period . It is suggested that these changes reflect changes with time in the substrate since the flood-induced scouring of these estuaries, particularly the gradual accumulation of detrital material, and the changing availability of food for the different trophic groups .

Beyond corals and fish: the effects of climate change on noncoral benthic invertebrates of tropical reefs

“…Reduced salinity can be lethal to invertebrates on reef flats emersed at low tide during heavy rain or freshwater lenses of river plumes (Fabricius & Alderslade, 2001;Gillanders & Kingsford, 2002;Fabricius et al, 2007). The complete loss of benthic communities has been documented after massive floods in Queensland (Moverley et al, 1986). Flood plumes often contain nutrients, top soil, and pesticides which impact negatively on octocorals, making them more susceptible to fungal infections, colonization by algae, barnacles, bryozoans, or anemones; and high levels of mortality often occur (Smith et al, 1996;Nagelkerken et al, 1997;Fabricius & Alderslade, 2001).…”

Temporal variability of biodiversity patterns and trophic structure of estuarine macrobenthic assemblages along a gradient of metal contamination

“…The location of the SC area, upstream in the estuary in comparison to the other areas, may suggest that this area is more susceptible to the higher riverine flow due to the elevated levels of precipitation at the time. The increased riverine flow could be responsible for temporary shifts in macrobenthic community structure (Moverley et al, 1986;Norkko et al, 2002;Thrush et al, 2003;Chaínho et al, 2007;Cardoso et al, 2008;Baeta et al, 2011) that may cause additional disturbance effects. Additionally to seasonality and to variability in parameters like turbidity and hydrodynamics that may be affecting the assemblages and the result patterns in composition and structure (Bevilacqua et al, 2012), the small-scale spatial variation has been pointed as an important factor shaping the structure of macrobenthic communities (Mannino and Montagna, 1997;Cheng et al, 2004;Gim enez et al, 2014;Brauko et al, 2015).…”

Sampling patchily distributed taxa: a case study using cost–benefit analyses for sponges and ascidians in coastal lakes of New South Wales, Australia

“…For example, water quality can vary greatly among NSW lakes (Pollard 1994a, West & Jones 2000. Large-scale floods can dramatically change physical variables such as salinity, temperature, turbidity and pH and affect entire estuaries and assemblages of animals (Moverley et al 1986). Further, the magnitude and duration of changes after input of freshwater may vary greatly among different NSW coastal 61 …”