Tracking capybara (Hydrochoerus hydrochaeris) feces contribution method in aquatic environments using sterols

Area of Science:

• Environmental Science
• Analytical Chemistry
• Ecology

Background:

• Fecal contamination monitoring is challenging, with limitations in microbiological methods.
• Organic compounds like sterols can trace fecal sources, but capybara's contribution is poorly understood.
• Capybaras significantly impact aquatic environments due to their water dependency.

Purpose of the Study:

• To develop a method for measuring the temporal fecal contribution of capybara in aquatic systems.
• To establish specific sterol ratios for identifying capybara fecal sources.

Main Methods:

• Analysis of fecal sterol content in capybara and comparison with other species.
• Delineation and testing of six numerical ratios derived from fecal sterols.
• Application of identified ratios to sediment core samples from South Brazil.

Main Results:

• Three specific sterol ratios were identified that can differentiate capybara feces from other sources.
• Analysis of a sediment core revealed a significant temporal trend of capybara fecal contribution over the last 100 years.
• The developed method provides a tool for assessing capybara's impact on aquatic environments.

Conclusions:

• The study successfully developed and validated a method to trace capybara fecal contamination using sterol ratios.
• This tool is crucial for understanding and managing the ecological impact of capybara populations in aquatic systems.
• The findings highlight the long-term and significant contribution of capybaras to fecal pollution in studied areas.