News

WONDERFUL NEWS FOR BIRDERS AT THE ONRUS RIVER ESTUARY

Posted on the 31st May 2022

(This is my personal opinion drafted from a birding perspective – Anton)

We have over the years expressed concern about the massive increase of reeds in the Onrus River estuary. Several complaints and reports were submitted and we once even indicated that more than 50 bird species that had been present in the past had basically disappeared. The decrease in the diversity and quantity of bird species at the site was of concern. It should further be noted that during two recent CWAC counts at the lagoon not a single water bird was recorded. The great news is that something is finally being done about this.

The Onrus Ratepayers & Home Owners Association (ORHA) and the Onrus River Estuary Forum (OREF) in collaboration with the Overstrand local municipality have made a good start with their efforts to clear the reeds from the Onrus Estuary. This can only be done during a narrow time period to reduce chances of disruption of breeding of birds.

Previously it was impossible to see open water when standing along the edge. Credit: OREF
A section of the cut reed showing the open water, with the OREF platform and cut reeds to be removed by the municipality

 

 

 

 

 

 

 

 

 

As background we repeat a position statement by OREF from May 2021:
“Exciting news for all residents of Onrus, and others that use the Onrus River Estuary, is that on 22/04/2021 the Maintenance Management Plan (MMP) was approved by the Department of Environmental Affairs and Developmental Planning (DEA&DP) and granted to the Onrus River Estuary Forum (OREF) to lawfully proceed with the removal and maintenance of the reeds in the Onrus River Estuary.
The MMP allows for reed, and the accompanying sediment, to be removed from the mouth of the Estuary up to the R43 bridge, about 2km upstream of the mouth. Not all the reeds may be removed, some patches must be kept as habitat for animal species. The Onrus River falls within the Breede-Gouritz Catchement Management Area (BGCMA), and the full reed removal program will be managed and overseen by OREF.
Over the past number of years the Onrus River Estuary has changed from being a seasonally closed estuary with a relatively large open water lagoon, to a shallow lagoon dominated by robust reed species. This is due to changes in the catchment land use, and because the building of the De Bos Dam (7.2km N of the mouth) has resulted in the reduction of floods that would previously have flushed sediments from the river.
This lack of river flow, together with lack of tidal action to flush the sediments, has resulted in sediment deposits building up around the estuary, providing an environment for the robust reed species, Phragmires Australis, to become established. The monoculture of reed species has reduced the overall biodiversity of the estuary, making it necessary to remove the reed in order to improve the ecological integrity of the estuary. This will also enhance the recreational utility of the estuary.
The MMP allows for the mechanical cutting of reeds to be followed up by the application of appropriate herbicides, as well as the manual removal of reed rhizomes with the accompanying sediment. Dredging is not part of the plan. The reeds must be removed from the site; they are not allowed to be burnt in an urbanized area. The cut reeds will be stockpiled in designated areas where they will be allowed to dry out, and then be compacted and disposed of. Alternative uses, such as converting the cut reeds to feedstock, will also be investigated.”

The extent of reed investation at the mouth
A section where reeds have been cut

 

 

 

 

 

 



All interested and affected parties have been contacted.
For more information please contact: Onrus River Estuary Forum
Responsible Person: Mr. Andrew Greeff
P.O. Box 47, Onrus River, 7201
Tel: (028) 313 1966
E-mail: andrewgreeff@icloud.com

Work is now in progress and is being reported on widely – see the latest edition of The Village News on its Facebook page and watch social media in general. Yesterday Johan van der Westhuizen contacted me with feedback on species recorded in the area where reeds had been cut. Species recorded by Johan at the lagoon on Monday 30 May: Levaillant's Cisticola, Reed Cormorant, White-faced Whistling Duck, Yellow-billed Duck, Little Egret, Western Cattle Egret, Egyptian Goose, Hadeda, Sacred Ibis, Common Moorhen, African Swamphen and Lesser Swamp Warbler. Other species: Southern Fiscal, Cape Weaver. Additional species recorded on Tuesday 31 May: Red-knobbed Coot, African Darter, Black-crowned Night Heron, Black-headed Heron, Grey Heron, Pied Kingfisher and Little Rush Warbler. This certainly suggests that many bird species should return to the lagoon as appropriate foraging areas are re-established! One hopes that even the waders will return in future.

White-faced Whistling Ducks on 30 May. Credit: Johan van der Westhuizen (2)
African Swamphen on 30 May

 

 

 

 

 

 

 

 

 

 

 

A BirdLife Overberg team doing a regular quarterly CWAC count that is now being done along all Overstrand estuaries
Labourers hard at work clearing reeds along the Onrus estuary

 

 

 

 

 

 

 

 

 

 

It is evident that this is a long term project and that several issues will have to be addressed. As stated above the mechanical cutting of reeds will have to be followed up by the application of appropriate herbicides, as well as the manual removal of reed rhizomes with the accompanying sediment. This clearly implies that ongoing work will have to be done. Social media responses at this stage relate to the use of appropriate herbicides, but it should be noted that OREF members have been referred to applicable specialists in the field of the use of herbicides in natural habitats. Complaints are also being levelled on social media regarding the lack of transparency and inadequate public participation during the planning process. It is our belief that these perceived problems can be resolved and that the Onrus River estuary can be restored to its former glory as a top birding destination.

OREF, ORHA and the Overstrand local municipality should be commended for their brilliant initiative and dedication to conservation in general and birds and birding in particular. They will need all the help they can get and volunteers can contact Andrew at the contact details above.

 

 

 

 

 

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