Conserving the rich biodiversity has been the primary cause of the Mt Pihanga–Rotopounamu project, jointly undertaken by the Department of Conservation and Project Tongariro. This report by Nicholas Singers describes the background and the plans to succeed with this ambitious project, as well as the earlier results : Mount Pihanga — Rotopounamu Forest Sanctuary Pest Monitoring Results 2015–16 (page 82).
Mustelids are the primary objective of the trapping in this area in order to better protect nesting kaka and kakariki, which are more vulnerable to these predators, being cavity nesters.
Overall catches, including rats reduce in periods after 1080 drops (August/September 2015 and 2018). Significant catches are recorded along road and track (lines B and ), where rats feast on rubbish and food scraps left behind by visitors. H-line (between the farm and the reserve at the Tokaanu side has only been established recently and catches significant numbers of hedgehogs.
The map below shows the mustelid catches by trap since we put the 200+ traps out about this time in 2013 with a color code, so it becomes clear where mustelids are most abundant or never caught at all.
The surprising part is the large number of traps and locations of where mustelids are not caught or caught infrequently. There appears to be some logic to this. For example the lowest catch rates are at the highest altitude (e.g. on Tihia), cooler south facing locations or on steep terrain sites. Conversely, the traps which have caught most are near the seat on long beach where probably the most litter and food scarps are!
We should use this data to see if we can improve trap locations to be more effective. It makes sense to move some of the ‘unproductive traps’ and locate them to areas of potential better suitability for stoat control — perhaps like further north on the saddle road toward Turangi.
The best sites are warm & dry, located on pest runs and also so positioned so pests can look through the trap. Places which should be avoided are wet sites especially where there are a high cover of ground ferns, especially kiokio. There is no harm moving traps (which have never caught anything), short distances along the trap line to warmer and sunnier spots. If you do that please use a GPS and make sure the coordinates are updated in trap.nz, with details to be forwarded to Nicholas Singers.