Waihi North Project: Assessment of Terrestrial Ecological Values & Effects 62138 WNP AEE 49 60-90 ferns, 20-30 Orchids, 50 grasses, 40 composite and monocot herbs, and around 70 dicot herbs. These lists are extensive and produced by numerous experts and dedicated botanical society groups over time. A typical point in time assessment will not record these numbers of species but a good survey will approximate at least these numbers in the larger tree and shrub and fern taxa. Each of: Treefern scrub, pine forest with rewarewa, rewarewa forest and kauri treeland are assessed against the EIANZ (2018) values guidance criteria: representativeness, rarity and distinctiveness, diversity and pattern and context. 5.3.1.3.1 Treefern scrub - approximately 15ha (26% of the southern fragment of SNA 166), generally central to the SNA but with a few patches east and west. Representativeness. The vegetation and habitats of this youngest regenerating seral community are depauperate of many of the typical seral community species expected of a natural seral process. As a result, a lower species richness is noticeable in part due to the fragment’s isolation, but also the limited time since it was cleared and the encroachment of weeds. Structural elements are missing (no canopy species and no emergents); there is limited appropriate ground cover, limited epiphytes, and the current canopy is not intact. Despite being an early seral regeneration stage, it is not sufficiently representative of that community type formed under natural processes. Given the array of species and structures expected, we must judge this area as of low representative value and note that it remains prone to dominance by encroaching pine into the future (without management). Rarity and distinctiveness No threatened, naturally uncommon or rare species were recorded. Again, we note the presence of kānuka and mānuka which we do not consider triggers rarity or distinctiveness values. In 2012 two moko skink were identified at one location “within” this vegetation unit (in open grassland alongside a track (Bioresearches 2012)). Because this species is an open environment, high sunlight, habitat specialist, its use of this vegetation type is very restricted and considered relict. Therefore, as the vegetation matures, it is possible that this species could be lost to the system, or become confined to the outer edge of the SNA (possibly with management, because survey effort did not record them there). We conservatively accept moko skink as part of this community, and therefore rank this criterion as moderate (being an “At-Risk-relict” classification). Diversity and Pattern Being a simple early seral community in a modified landscape with restricted seed propagule potential, the diversity of species is limited. Also, the diversity of environmental gradients (hydrology, soils, slopes, etc) is relatively uniform and there do not appear to be any mosaics, patterns, or subunits representing nuances in assemblages related to environmental gradients. We judge the diversity and pattern to be low. Ecological Context. The size and shape of the central block of treefern scrub in the SNA 166 southern fragment is relatively large at nearly 20 ha and is more or less a solid shape. It has potential, if not for the young age and still evident tracks, to have a core habitat less affected by edge effects sometime in the future if it were to develop sufficiently well. That development is however in doubt with the current weed (including pine) elements present and the general lack of final native canopy species regeneration present (rewarewa is showing sign of regeneration but kauri and pōhutukawa are not
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