Estimating the proportion of Archey’s frogs in the Wharekirauponga mine vibration footprint 16 Table 9. Total population estimates obtained from density estimates for seven habitat types described by NZ LRI vegetation type and altitude. Source Veg. Altitude Area Density Estimate Population Estimate Type (m a.s.l.) km2 ha-1 SE N. Pop SE 1a) M1 200–500 85.58 928.8 ±131.0 7,948,566 ±1,121,142 3a) M1 ≥500 3.58 37.5 ±6.3 13,415 ±2,247 M4 0.39 . M5 7.08 . 2a) N2, ex. n3a 74.06 217.4 ±120 1,609,971 ±887,695 2b) N2, n3a 227.36 993.8 ±220 22,594,867 ±5,001,217 3b) N3a 200–500 14.64 580.6 ±61.3 850,127 ±89,786 3c) N3a ≥500 72.84 1,902.2 ±127 13,854,562 ±922,258 N3b 6.83 . 1b) N5 28.58 407.6 ±73.0 1,164,878 ±208,643 P1 11.71 . P2 45.73 . Area N. Pop SE Total : 578.4 (km2) Total: 48,036,386 ±5,287,655 Area without estimates: 71.75 (CI95%: 37,672,385 – 58,400,189) Sources: 1a) Wharekirauponga, C-R from Hotham (2019); 1b) Mahakirau, C-R from Hotham (2019); 2a) Wharekirauponga, 2018–19; 2b) Wharekirauponga, 2018–19; 3a) Crosbies, 2022; 3b) Golden Cross, 2022; 3c) Tapu Ridge, 2022. The sum of population estimates for areas of the eight habitats with density estimates is 48,036,386 (CI95%: 37,672,385–58,400,189). However, there are no density estimates, and consequently no population estimates, for areas dominated by five of the NZ LRI vegetation types (M4, M5, N3b, P1 and P2) occurring within the frog’s known range. These areas comprise 12.4% (71.2 km2) of the frog’s range and include 12.1% (43) of Archey’s frog records in the Amphibian & Reptile Distribution Scheme. Adjusting the total population estimate to account for the 12.4% of the known frog range without population estimates increases the total population estimate by 14%, (i.e. 2.4%/(100%-12.4%) ), to 54,839,115 (CI95%: 43,000,630–66,670,600). This population estimate does not include frog populations in areas of suitable habitat below 200 m, or areas of frog habitat not contiguous with the main block of habitat on the axial mountain range. The duplicate estimates for low altitude (200–500 m a.s.l.) manuka-kanuka scrub are not significantly different, despite being obtained using different methods (Tables 6 & 8) and with counts from different plots. The population estimate in Table 9 was obtained using a density estimate from Hotham’s (2019) capture-recapture study (929 ha-1; CI95%: 643– 1,186). Replacing this estimate with the estimate in Table 8 from nocturnal plot counts (1,111 ha-1; CI95%: 702–1,520) only increases the total population estimate of 54,839,115 Archey’s frogs by 2.8% (1,557,223).
RkJQdWJsaXNoZXIy MjE2NDg3