Data from: Examining disease prevalence for species of conservation concern using non-invasive spatial capture-recapture techniques

1. Non-invasive techniques have long been used to estimate wildlife population abundance and density. However, recent technological breakthroughs have facilitated non-invasive estimation of the proportion of animal populations with certain diseases. Giraffes (Giraffa camelopardalis) are increasingly becoming recognized as a species of conservation concern with decreasing population trajectories across their range in Africa.
2. Diseases may be an important component impacting giraffe population declines, and the emerging ‘Giraffe Skin Disease’ (GSD), characterized by the appearance of wrinkled skin and alopecic lesions on the limbs, neck, and chest of infected giraffe, may hinder movement causing increased susceptibility to predation.
3. We examined the prevalence of GSD in Tanzania’s Ruaha National Park over a 4-month period in 2015, using photographic capture-recapture surveys via road-based transects. We divided the study area into 5 circuitous survey units, each approximately 100 km in length ("x̅" = 99.22 km, SD = 3.72), and surveyed for giraffes for four months. From these surveys, we developed a database of spatially-explicit giraffe photographs.
4. We processed these photos for individual identification and fitted spatial capture-recapture models to predict the spatial configuration of giraffe abundance and GSD prevalence within the study area.
5. Our results indicated that >86% of the giraffe population showed signs of GSD and that the disease was more prevalent in the northern and northeastern portion of Ruaha National Park.
6. We discuss the implications of this research for conservation of threatened species with an emphasis on disease ecology and vulnerability to predations, and more broadly, for wildlife conservation.