First Progress Report - 2. to identify and define suitable sites for trial of Tradescantia control methodology
Tradescantia is dominant over much of the streambank from the Easton Park Parade area, covering a large proportion of the streamside
https://inaturalist.nz/observations/22728050
where it is both washed away and reintroduced in successive flood cycles, leaving in many places a light-to-moderate coverage intermixed with native plants, especially where hand-weeding was done throughout 1997-2000:- https://inaturalist.nz/observations/22186256
In contrast, upper banks
and roadside margin of canopy, mainly planted 1999
have few wild native plants among the tradescantia, mainly juvenile mahoe, kawakawa and coprosma both large and small-leaved.
In this roadside-planting area of tradescantia there are many scattered invasions of tree privet, Elaeagnus, wattle, Japanese honeysuckle, moth plant, Calystegia silvatica x sepium sp roseata, blackberry, and one area (c. 20m) of German ivy.
This pattern continues a distance of approx 1km., to just upstream of the estuary
https://inaturalist.nz/observations/18149485
Most of this length is too steep to work on regularly in all seasons, especially those areas raised and/or steepened with roading fill in 1999.
The area selected for this Trial is therefore approx 60mx50m of roadside streambank opposite Glenfield College tennis courts. This area is readily accessible from the roadside, and contains what we will call Trad zones of varying moisture level, proximity to wild revegetation, existing diversity, and light exposure.
eg Zone DbKR (Db at Kaipatiki Roadside)
https://inaturalist.nz/observations/21771305
and CaTWS (Ca on the stream side of the Native Plant Trail, also known as Taraire Walk as the highest point of the Trail is in densely shaded forest including an old taraire)
https://inaturalist.nz/observations/17555743
https://inaturalist.nz/observations/17555734
signposted at the its entry beside the North Shore City Council site-interpretation sign.
https://inaturalist.nz/observations/13796086
This area was roughly indicated with map and photos in our funding application to RENH.
A pleasing challenge to finding an accessible site is that in the 18 years since we were fully acquainted with the Stream as a whole, much of the streambank is no longer accessible except to the intrepid adventurer, due to its now dense understorey.
https://inaturalist.nz/observations/21490536
while other areas are level enough to hand-weed, and require the high level of care provided by hand-weeding to avoid damaging vegetation.
https://inaturalist.nz/observations/18151257
In such densely vegetated areas, removed tradescantia may need to be bagged and carried to the nearest space suitable for decomposition, ie an area of pathside where revegetation has not yet occurred, perhaps due to soil compaction by pedestrians, drought from lack of adjacent ground cover and/or shade, or suppression by herbicide.
Many photo observations have been made of the Tradescantia Trial site pre-intervention and following first interventions, and are being assembled to illustrate the methods and effects of the Trial Methodology over the remainder of 2019.
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