Estimating the proportion of Archey’s frogs in the Wharekirauponga mine vibration footprint 22 (Manuka and/or Kanuka Scrub, Broadleaf Indigenous Hardwood Scrub, and Indigenous Forest) in the main block of Archey’s frog habitat, compared to seven classes in the NZ LRI database (Table 1). Any reduction in the area of indigenous woody vegetation in the main block of Archey’s frog habitat during the forty years since the NZ LRI database was created will lead to overestimation of the frog population. However, comparison between the NZ LRI and LCDB databases show only a minor (2.1%) decline in the total area of indigenous woody vegetation from 822.9 km2 in 1983 (NZ LRI) to 805.9 km2 in 2018 (LCDB), as a result of conversion of small areas of privately owned manuka or kanuka scrub into exotic forestry or pasture. There will have been changes in the quality of habitats since the NZ LRI database was created as a consequence of various factors including: climate change, habitat degradation due to browsing, successional changes from scrub to forest, and regeneration of cutover kauri forest. Although changes in habitat quality will have resulted in changes in the frog population over time, they should not affect accuracy of our population estimates because the estimates are based on frog density estimates from surveys in the habitats within the last four years. Discrepancies between our results and earlier observations[4-6] that Archey’s frogs were less abundant at low altitudes and in areas of manuka-kanuka scrub or kauri re-growth are noteworthy. At 929 ha-1, 1,111 ha-1 and 994 ha-1, density estimates for Archey’s frog (Tables 6 & 7) in low altitude manuka-kanuka (100–300 m a.s.l) and kauri forest (200–400m a.s.l.) in the Wharekirauponga catchment were among our highest density estimates. High numbers of Archey’s frogs in low altitude manuka-kanuka scrub and kauri forest are not confined to the Wharekirauponga catchment, as high numbers of Archey’s frogs were also observed during a nocturnal transect survey through low altitude manuka-kanuka scrub and kauri forest four kilometres north of Wharekirauponga (Figure 6 and Table 4). The discrepancy between our results and earlier observations could be a result of biases in previous worker’s search effort, but is more probably a consequence of improvements in the quality of habitat in regenerating manuka-kanuka scrub and cut-over kauri forest over the last forty, or more, years. The development of more complex interior forest structures and colonisation by old-growth forest species during the regeneration process will have improved habitat quality for Archey’s frogs. The role of successional changes in the quality of habitat is supported by comparison between areas of vegetation types in the NZ LRI and LCDB spatial databases. There is a 70% decrease in the area of manuka-kanuka scrub from 230 km2 in NZ LRI to 70 km2 in LCDB. Only 10% of this decrease is a result of conversion to plantation forestry or pasture. Most of the decrease in the area of manuka-kanuka scrub can be attributed to successional changes occurring during the 30–40 years between compilations of the two databases with the area of later succession indigenous woody vegetation increasing by 26%. The similarity of the two estimates of the number of frog in the predicted ≥2 mm sec-1 vibration footprint is reassuring, as the two estimates were obtained using different analytic methods with data from different sets of plots (Figures 10 a & b). The population estimate of 289,887 (CI95%: 202,373–373,364) was obtained using capture-recapture methods with data from 22 plots, while the other population estimate of 315,917 (CI95%: 198,909–432,925) was obtained using counts from a different set of 68 plots. Although the two estimates are
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