Estimating the proportion of Archey’s frogs in the Wharekirauponga mine vibration footprint 4 Numbers and density of records varied between NZ Land Resource Inventory (NZ LRI)[2] vegetation typesiii (Table 2), with 169 records in kauri forest (N2), 107 in lowland podocarphardwood forest (N3a), 29 in manuka-kanuka scrub (M1) and 21 in sub-alpine scrub (M5) on Mt. Moehau. The remaining 29 records were in a variety of other vegetation types. However, highest densities of Archey’s frog records were in sub-alpine scrub (2.97 records/km2), fernland (2.55 records/km2), and lowland podocarp-hardwood forest (1.22 records/km2); with lower densities in kauri forest (0.56 records/km2) and manuka-kanuka scrub (0.33 records/km2). Table 2. Numbers and density (N/km2) of recorded Archey’s frog sightings in the frog’s known range on the Coromandel by dominant NZ Land Resource Inventory (NZ LRI) vegetation types. Dominant NZ LRI Vegetation Type Area N. frog records Percent of records Record density Manuka-kanuka scrub M 1 89.16 29 8.2% 0.33 Fern M 4 0.39 1 0.3% 2.55 Subalpine scrub M 5 7.08 21 5.9% 2.97 Mixed native scrub M6 0 0 0 0 Kauri forest N 2 301.42 169 47.6% 0.56 Lowland podocarp-hardwood forest N3a 87.48 107 30.1% 1.22 Mid-altitude podocarp-hardwood forest N3b 6.83 1 0.3% 0.15 Hardwood forest N 5 28.58 7 2.0% 0.24 High producing pasture P 1 11.71 1 0.3% 0.09 Low producing pasture P 2 45.73 19 5.4% 0.42 All vegetation types 578.39 355 0.61 When mosaic plots[3] are used to visualise the combined effects of elevation and vegetation type, it is apparent that the highest numbers of frog records are from lowland podocarphardwood forest (N3a) in the ≥400<500 m elevation band and kauri forest (N2) in the three elevation bands from ≥200 to <600 m (Figure 4a). However, the highest densities of records are from mixed podocarp-hardwood forest (N3a) in the ≥700<800 m elevation band and subalpine scrub (M5) in the ≥800 m band (Figure 4b). There are fewer records of Archeys’s frogs than expected from steep areas with only seven of 364 (i.e. 1.9%) records on areas >30°, which account for 4.1% of the frog’s Coromandel range. It is possible that it is searchers, not frogs, that avoid steep areas with slopes >30°. iii In the NZ LRI mapping system, there are ten primary vegetation types ≥200 m a.s.l. on the Coromandel Peninsula’s axial mountain range (Table 10). Individual areas of vegetation are classified using up to three vegetation types, with the dominant vegetative type first, followed by any other vegetation types in descending order of prominence. Lower case letters indicate a vegetation type covers ≥40% of the area, while lower case letters indicates a vegetation type covers >10%< 40% of the area. Permutations of the ten primary NZ LRI vegetation types give 76 different vegetation types on Coromandel’s axial mountain ranges.
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