leonlobo's Identifications

The sole species in a canopy approx 100m x 20m, on margins of a much wider kanuka/manuka canopy, itself along the Eastern margin of Eskdale Forest, regenerating native forest.

The greatest native ground cover is by Gahnia, xanthocarpa ID's so far. There are some sedges including Square sedge.

Where Gahnia are absent, Watsonia cover much of the ground both in shade and (increased density) in light, with occasional dead gorse, scattered pampas plants with only 1-3 of the independently rooted portions (what is the right word? the erect sections usually seen in much greater numbers forming a wide-based clump) to c1mH, common slender karamu to c2mH, occasional totara and spindly manuka to c2m and Leucopogon fasciculata to 1mH, with only an occasional to kouka approaching the canopy. Common exotic Iris.

The soil is poorly drained clay. Its history is apparently pine plantations. An aerial photo of the whole reserve from 1963 shows what appears to be almost entirely bare ground.

For other observations of species and habitat of the site see Gahnia Grove Project, https://inaturalist.nz/projects/gahnia-grove which includes c50x20m of this manuka canopy, and c50x20m of the adjacent kanuka/manuka canopy which is taller and more diverse, and adjacent an area of stormwater runoff, with hangehange, ponga, pigeonwood, and some ginger, agapanthus and elaeagnus.

Being entirely unfamiliar with this sole-species manuka situation, my questions are:

Are the apparently-young (?) Pampas dying due to diminished light? ie could they have germinated during the development of this manuka canopy? Or have they arisen more recently, with the loss of parts of the canopy?

Why is there not more development of a replacement canopy? eg Will the scattered karamu erupt into growth in time to prevent more light invasion?
Or are the many native seedlings, and even perhaps the juvenile karamu and mapou, being suppressed by the Watsonia sufficiently to have delayed the development of a replacement canopy in time to prevent light invasion? There are several dead manuka already; is this the limit of their lives?
If this is the case it seems that , without intervention, the next few years will result in increased weed invasion, likely to prevent native canopy formation.

Seedlings are numerous where there are gaps between Watsonia; mostly mapou and large-leaved coprosma, with scattered totara, kahikatea, small-leaved coprosma, mapou, and rare tanekaha.

The abundance and density of the fibrous extensions of the "nets" that cover Watsonia bulbs suggest there are many more Watsonia bulbs below the ground surface,in addition to the ones indicated by their green leaves.