Demography and welfare status of free-roaming dogs in Yangmingshan National Park, Taiwan.

Free-roaming dogs (Canis familiaris) cause threats to native wildlife and public health and raise concerns for their welfare. Understanding the demography of free-roaming dog populations is essential for developing an effective management plan. An evaluation of their welfare status would be beneficial to earn public support for the management plan. In this study, we estimated the population size, survivorship, and health of a free-roaming dog population in Yangmingshan National Park (YMSNP), Taiwan, during 2016-2018. YMSNP is a rural area with human settlements but also a protected area of conservation concern. We identified 191, 176, 216 individuals at our sampling sites in 2016, 2017, and 2018, respectively. Using a photographic capture-recapture method and extrapolation, we estimated that there were 786-979 dogs in the park during this 3-year period. The annual apparent survival rate of identified dogs was 16.7% for 2016-2017 and 23.9% for 2017-2018. The dogs had a high rate of lameness and dermatosis of 5.1-8.8% and 14.2-18.1%, respectively. Thirty-five blood samples showed that 34.3% of the dogs were anemic, 37.1% showed abnormal white blood cell counts, and 68.6% exhibited abnormal platelet counts. These results suggested that the dogs were at high density with low survivorship and in poor health, and new individuals entered the population continuously. Interventions to manage this dog population and to improve their welfare must be carried out. Our study provides an example for monitoring and managing a free-roaming dog population in a rural, conservation area in Southeast Asia.