Comte Sebastien, Carver Scott, Hamede Rodrigo, Jones Menna
School of Natural Sciences, University of Tasmania, 7001, Hobart, Australia.
Vertebrate Pest Research Unit, NSW Department of Primary Industries, 2800, Orange, Australia.
Glob Ecol Conserv. 2020 Jun;22. doi: 10.1016/j.gecco.2020.e00993. Epub 2020 Mar 3.
Epidemiological studies commonly monitor host population density but rarely account for how transmission dynamics might be influenced by changes in spatial and social organization that arise from high mortality altering population demography. Devil facial tumour disease (DFTD), a novel transmissible cancer, caused almost 100% mortality of its single host, the Tasmanian devil, and a >90% local population decline since its emergence 20 years ago. We compare size and overlap in home ranges in a devil population before and 15 years after disease outbreak. We used location data collected with VHF tracking collars in 2001 and GPS collars in the same area in 2015 and 2016. Density of adult devils, calculated from live trapping data in the same years, show a strong decrease following the disease outbreak. The decline in density was accompanied by a reduction in female home range size, a trend not observed for males. Both spatially explicit population modelling and animal tracking showed a decrease in female home range overlap following the DFTD outbreak. These changes in spatial organisation of the host population have the potential to alter the local transmission dynamic of the tumours. Our results are consistent with the general theory of sex-biased spatial organization mediated by resource availability and highlight the importance of incorporating spatial ecology into epidemiological studies.
流行病学研究通常会监测宿主种群密度，但很少考虑高死亡率改变种群人口结构所引发的空间和社会组织变化可能如何影响传播动态。袋獾面部肿瘤病（DFTD）是一种新型的可传播癌症，自20年前出现以来，导致其唯一宿主袋獾的死亡率几乎达到100%，当地种群数量下降超过90%。我们比较了疾病爆发前和爆发15年后一个袋獾种群的家域大小及重叠情况。我们使用了2001年通过甚高频跟踪项圈收集的位置数据，以及2015年和2016年在同一区域使用GPS项圈收集的数据。根据同年活体诱捕数据计算得出的成年袋獾密度显示，疾病爆发后密度大幅下降。密度下降伴随着雌性家域大小的减小，而雄性未观察到这种趋势。空间明确的种群建模和动物跟踪均显示，DFTD爆发后雌性家域重叠减少。宿主种群空间组织的这些变化有可能改变肿瘤的局部传播动态。我们的结果与由资源可用性介导的性别偏向空间组织的一般理论一致，并强调了将空间生态学纳入流行病学研究的重要性。
