Re: Kooragang Island

Subject: Re: Kooragang Island
From: David James <>
Date: Mon, 09 Nov 1998 10:12:01 +1000
At 08:26 6/11/98 +1000, David Geering wrote:
>The Spiny Rush on Kooragang Island is Juncus actutus (or actuta - latin
>buffs please correct).  It is NOT a native but introduced in ships ballast
>water to the Hunter estuary.  To my knowledge it occurs only in this
>estuary.  It is a SERIOUS weed readily colonising wetlands, particularly
>those occasionally inundated by salt water.  The plants form impenetrable
>stands thus effectively rendering sites formerly used by shorebirds as
>roost sites completely unsuitable.
>Alan, my comments re. further work on Stockton Sandspit will be sent to you
>privately.  I was the original architect of the rehab. work there.  There
>are a few adjustments required, primarily due to the difficult hydrological
>David Geering
Juncus acutus L., also known as spiny rush, is a widely distributed
introduced weed in Aus. It occurs in numerous districts in sw WA, se SA,
throughout Vic but more in the west, and along the coast, ranges and w.
slopes of NSW. It is declared "Noxious: in most of Victoria. It likes humid
& subhumid temperate areas, in low-lying, low fertility situationsIt is
commonly found on coastal flats, mine -sites and disturbed saline areas. It
produces seed prolifically, the seed is small and papery and disperses
well, most notably by water. Its root system is a shallow fibrous mat with
short rhizomes. The rhizomes have been reported to block water flow in
channels. On the positive side, the spiny leaves may deter access to ta
site for dogs and humans. 

Just a thought, but are you sure that Juncus occurs beacause of lack of
inundation. My understanding is that it likes inundation and salt. Also,
which came first, the Juncus or the reduced inundation?

These control methods are recommended in Parsons & Cuthbert (1992) (Noxious
Weeds of Australia). 

(1) improving drainage (not appropriate at KI!)
(2) chemical control has had mixed results. 
(3) Mechanical control has been efective, but is expensive. There are a few
methods, one involving a yucca cutter (Specialised subsurface plough); a
stone-bucket designed for removing stones from paddoks, fitted to front-end
loader. The plants are then heaped and burned. This might be possible to
use under stockton  bridge in winter?? but not the delicate approach that
you would like.

Trouble is, it will recolonise from seed floating around the estuary. It
grows slowly, so if you get an area under control it might be possible to
keep it that way with one working bee a year until the problem can be
approached on a catchment scale. 


David James
PO BOX 5225
Townsville Mail Centre 4810

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