Invasive axis deer and wild boar in a protected area in Argentina, controlled hunting, and Taylor's law.

GÜRTLER RE; COHEN JE

WILDLIFE RESEARCH

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2022 vol. 49 p. 111 - 128

1035-3712

Context. Spatial and temporal variability in population density tends to increase29 with increasing mean density, as widely documented by Taylor?s law (TL) of fluctuation30 scaling. A management programme based on local hunters has been used to control31 invasive wild boar and axis deer in a protected area of northeastern Argentina since 2006.32 Aim. We determine the effects of species (boar or deer), hunting shift (diurnal,33 overnight), human disturbance (by comparing one section open for public use, one not) and34 time scale (one- versus three-month periods) on the values of TL?s parameters, and35 consider both its spatial and temporal forms.36 Methods. Park management collected data on the hunting efforts and harvest of37 6,104 hunting parties shooting from elevated blinds from 2006 to 2015. The log-38 transformed sample means and variances of four indices of relative abundance were39 computed for each period and blind, and analysed through least-squares linear regression40 and ANCOVA.41 Key results. Axis deer satisfied the spatial TL by all four indices, but wild boar had42 a significantly non-linear relationship for crude catch per unit effort (CPUE) only. In the43 spatial TL, the slope b did not deviate significantly from 1 when using crude or44 standardised catch per hunting party-session or standardised CPUE, but b was substantially45 above 1 for crude CPUE in both species (range, 1.307-1.434). Human disturbance, hunting46 shift, and time scale did not significantly modify the parameters of the spatial TL except in47 two cases. All metrics at identified blinds over consecutive trimesters confirmed the48 temporal TL. Wild boar crude catch was 43% greater in the restricted zone of greater49 conservation value whereas axis deer catch was 60% greater in the public-use zone.50 Conclusions. With rare exceptions, TL describes well the mean and variance of four51 metrics of abundance of wild boar and axis deer under sustained hunting pressure. This52 paper may be the first to demonstrate the connection of TL with any aspect of vertebrate53 pest control.Implications. TL identifies key zones with high mean and high variance of ungulate55 density for targeted control, and can be used to attain fixed-precision estimates of56 abundance through sequential sampling.