Hunting pressure a key contributor to the impending extinction of Bornean wild cattle

16 Widespread and unregulated hunting of ungulates in Southeast Asia is resulting in population 17 declines and localised extinctions. Increased access to previously remote tropical for est 18 following logging and changes in land-use facilitates hunting of elusive wild cattle in Borneo, 19 which preferentially select secluded habitat . We collated the first population parameters for 20 the endangered Bornean banteng and developed population models to simulate the effect of 21 different hunting offtake rates upon survival and the recovery of the population using 22 reintroduced captive-bred individuals. Our findings suggest that the banteng population in 23 Sabah is geographically divided into four management units based on connectivity; the 24

northeast, Sipitang (west), central and southeast, which all require active management to 1 prevent further population decline and local extinction. With only 1% offtake, population 2 growth ceased in the northeast and Sipitang. In the southeast and central units, growth ceased 3 at 2% and 4%, respectively. Extinction was estimated at 21-39 years when offtake was 5%, 4 occurring first in Sipitang and last in the Central unit. Supplementing the population with 5 captive-bred individuals suggested that inbreeding was likely to limit population growth if 6 using 20 founder individuals or less. Translocating two individuals for a 10-year period, 7 starting after 20 years of captive breeding resulted in a faster population recovery over 100 8 years and a lower extinction probability. Our results suggest that shielding the population 9 against further losses from hunting will be key to their survival in the wild, providing active 10 management in the form of captive breeding is developed in the interim.

Introduction
Firearms and dogs have been the commonly-used methods since the early 19 th century 23 (Rutter, 1922), but the prospects of hunting success have dramatically improved given the 24 provision of semi-automatic weapons and firearm sights, together with off-road vehicles, excavators used in timber extraction, boats and motorbikes. Bornean banteng are also caught 1 in snares; enduring major injuries such as hoof dismemberment as a consequence of single-2 strand snares set at ground level along trails and abandoned logging roads in the forest 3 (Gardner et al., 2019). 4 Over the past three decades, a declining trend in Bornean banteng has been described 5 (Boonratana, 1997;Davies & Payne, 1982;Hedges & Meijaard, 1999;Olsen, 2003 Sabah describe sourcing of wild cattle bushmeat for logging camps during the 1980s and 10 1990s, thus reducing and in some cases, completely eradicating, any remaining individuals.

11
In years following the extraction of timber, the access provided by abandoned logging roads 12 has also almost certainly increased hunting pressure (Kleinschroth & Healey, 2017).

13
The Bornean banteng is a 'Totally Protected' species and listed under Schedule 1 of the  et al., 2006), in Northern Australia (Bradshaw et al., 2007;Choquent, 1993 research, and were agreed at a stakeholder consultation process; 2) using the intrinsic rate of 18 growth from the above model to test whether the baseline model was parameterised  approximately 4% of the total Sabah population may be poached annually at the present time.

17
A variety of harvest models were developed to examine offtake rates at 1, 2, 3, 4 and 5% of 18 the starting population size for all populations. Additional models were proposed in order to 19 examine the combined effect of sustained offtake with catastrophic poaching events (mass 20 killings), but these were not pursued because they could not be reliably quantified.

21
Further modelling was carried out, first to model the establishment of a captive population the percentage of females breeding per year was carried out using parameters from Table 1 29 and 1,000 simulations. breeding per year (50%) with 1,000 simulations yielded an intrinsic growth rate of 4.3% ± 5.7 6 (SD). The results of this simulation can be found in Fig. 2. The estimated population-specific parameters comprised population size, carrying capacity and 9 its trend, and can be found in    (Table 4). Hunting was, as expected, a deterministic force for extinction in the model and 23

Results
we predicted that it needs to occur at very low levels (<1% per annum, if it goes on beyond 50 24 years). The current rate of harvest on the ground in Sabah, which may be as high as 4% per annum, is expected to result in the extinction of the Bornean banteng with 39% to 96% global 1 probability (4 and 5% offtake, Table 4).      PHVA group assessmentbachelor groups are common and harems comprise one adult male to five adult females.