title: Declines of seagrasses in a tropical harbour, North Queensland, Australia, are not the result of a single event.
abstract: A recent paper inferred that all seagrass in Cairns Harbour, tropical north-eastern Australia, had undergone 'complete and catastrophic loss' as a result of tropical cyclone Yasi in 2011. While we agree with the concern expressed, we would like to correct the suggestion that the declines were the result of a single climatic event and that all seagrass in Cairns Harbour were lost. Recent survey data and trend analysis from an on-ground monitoring program show that seagrasses in Cairns Harbour do remain, albeit at low levels, and the decline in seagrasses occurred over several years with cyclone Yasi having little additional impact. We have conducted annual on-ground surveys of seagrass distribution and the above-ground meadow biomass in Cairns Harbour and Trinity Inlet since 2001. This has shown a declining trend in biomass since a peak in 2004 and in area since it peaked in 2007. In 2012, seagrass area and above-ground biomass were significantly below the long-term (12 year) average but seagrass was still present. Declines were associated with regional impacts on coastal seagrasses from multiple years of above-average rainfall and severe storm and cyclone activity, similar to other nearby seagrass areas, and not as a result of a single event.
authors.affiliation: Centre for Tropical Water and Aquatic Ecosystem Research, James Cook University, Queensland, Australia, skye.mckenna@jcu.edu.au.
authors.forename: Skye
authors.initials: S
authors.lastname: McKENNA
authors.forename: Jessie
authors.initials: J
authors.lastname: Jarvis
authors.forename: Tonia
authors.initials: T
authors.lastname: Sankey
authors.forename: Carissa
authors.initials: C
authors.lastname: Reason
authors.forename: Robert
authors.initials: R
authors.lastname: Coles
authors.forename: Michael
authors.initials: M
authors.lastname: Rasheed
mesh_terms: D001315:Australia; D018533:Biomass; D017753:Ecosystem; D004784:Environmental Monitoring / Q000706:statistics & numerical data*; D008386:Marine Biology / Q000639:trends*; D006109:Poaceae / Q000254:growth & development*; D011793:Queensland; D011891:Rain