Seagrasses in Port Curtis and Rodds Bay 2016: annual long-term monitoring

Rasheed, M.A., Wells, J.N., and Carter, A.B. (2017) Seagrasses in Port Curtis and Rodds Bay 2016: annual long-term monitoring. Report. James Cook University, Cairns, QLD, Australia.

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Abstract

In 2016, seagrasses in Port Curtis and Rodds Bay remained in an overall poor condition. The results for individual meadows and regions however, were mixed, with some meadows improving in condition and others declining since 2015.

There was no clear relationship between distance from anthropogenic activities and seagrass condition, with many of the meadows in improved condition closest to port activity and some areas furtherest away experiencing declines.

It is important to note that meadows can be classified as being in poor condition if any one of the three key indicators (biomass; area; species composition) were poor, even if the other two indicators had improved. For some meadows this was the case in 2016, especially those that had started to recover from recent declines with the key species yet to return.

Of most concern was the significant decline in biomass for the largest and most stable seagrass meadow in the Port Curtis region, Pelican Banks. This meadow between Curtis and Facing Islands was in very poor condition in 2016 with the lowest ever recorded biomass, smallest area and a decline in the make-up of species.

The reasons for the decline in this substantial area of seagrass are unclear. Monitoring of light and climate drivers showed a generally favourable environment for seagrass growth in 2016. There are a range of potential contributors to the decline of this meadow. High levels of herbivory from dugong and turtle, movement of sediments on banks, and the range of repeated disturbances from climate, floods, cyclones and anthropogenic activities offer possible explanations but require further investigation.

Seagrasses in the out of port reference area at Rodds Bay also deteriorated in 2016 and were found to be in a very poor condition. These meadows have been in a poor state since substantial declines between 2008 and 2009.

Dugong continue to make use of seagrasses throughout the Port Curtis and Rodds Bay area including areas of high port and industrial activity.

Resilience of seagrasses in Port Curtis to further natural or anthropogenic impacts is likely to be low. In 2016, seed banks remained in key meadows and some seagrass was maintained across most of the historical extent of seagrass distribution. However, both were at substantially reduced levels. Climate and weather conditions during 2017 will play a critical role in determining the trajectory of seagrass change.

Item ID: 70852
Item Type: Report (Report)
Keywords: seagrass, Gladstone, monitoring, report card
Copyright Information: © James Cook University, 2017.
Funders: Gladstone Ports Corporation (GPC)
Date Deposited: 16 Nov 2021 23:48
FoR Codes: 41 ENVIRONMENTAL SCIENCES > 4104 Environmental management > 410402 Environmental assessment and monitoring @ 100%
SEO Codes: 18 ENVIRONMENTAL MANAGEMENT > 1802 Coastal and estuarine systems and management > 180201 Assessment and management of coastal and estuarine ecosystems @ 100%
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