Impact of domestic dogs on wild ungulates

• Grant number: 25/22954-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2026
• End date: March 31, 2027
• Field of knowledge: Biological Sciences - Ecology - Applied Ecology
• Principal Investigator: Márcio Leite de Oliveira
• Grantee: Isabela Liberato Pedrazolli
• Host Institution: Universidade de Araraquara (UNIARA). Araraquara , SP, Brazil
• Associated research grant: 24/18433-5 - Impacts of Hunting Pressure on Forest Ecosystems, AP.R

Abstract

The loss of biodiversity is among the most critical consequences of today's environmental crisis and global change. In particular, the interaction between domestic animals and wildlife represents a growing threat to wildlife. In the Atlantic Forest, free-ranging domestic dogs are increasingly present within protected areas, often due to irresponsible ownership in surrounding communities. These dogs can prey on or disturb native species, especially large-bodied mammals such as forest ungulates. Despite their ecological importance and vulnerable status, the behavioral impacts of domestic dogs on forest-dwelling ungulates remain poorly understood. This project aims to evaluate the influence of domestic dog presence on the temporal activity patterns of five species of forest ungulates (Dicotyles tajacu, Mazama rufa, Mazama nana, Tapirus terrestris, and Tayassu pecari) in Iguaçu National Park, a large protected area in the Atlantic Forest biome. Using 78 camera traps deployed across 26 adjacent sampling units (600 m radius), photographic records collected between August and December 2025 will be used to compare activity patterns of ungulates in areas with and without prior records of domestic dogs. Activity patterns will be estimated using kernel density analyses for circular data, and temporal overlap between conditions (dog presence vs. absence) will be quantified and tested using Watson-Wheeler tests and overlap indices. A mixed-effects model will also be built to explore how ungulate detection varies with dog presence, forest edge distance, canopy height, and distance to water sources. Shedding light on potential behavioral changes in response to dog presence, this study will contribute to the understanding of indirect anthropogenic impacts on threatened mammal species and inform management strategies in protected areas. (AU)