The Effect of Common Reed on River Otter Habitat Use

The recent invasion of Phragmites australis (common reed) in the Big Bend region of the Platte River has made the need to examine its potential effects on river otters more critical. The ability of P. australis to rapidly alter both landscapes and habitats could have large affects on vulnerable populations, such as river otters (Lontra canadensis). This study will increase our understanding of the effects of this invasive plant on river otters – a flagship species for non-game conservation.

Goals

To increase the understanding of the effects of Phragmites australis (common reed) on river otters - flagship species for non-game conservation

Current Status

This project is complete with results compiled into a master's thesis. The study examined how otters use rivers with P. australis infestation, if otter den use in areas with P. australis was more or less than expected relative to availability, and identified differences in otter use of areas before and after P. australis treatments. Otter positions along the central Platte River were determined from radio tagged river otters in conjunction with GIS. Data collection ended in December 2009 with eighteen otters successfully implanted with transmitters and over 1,000 locations being recorded. The data analysis is complete and results were compiled into a master's thesis.

Below are some of the findings of how otters use different habitats.

• River otters used habitat non-randomly for unique den and resting sites. Agricultural areas were used less than expected; water, riparian vegetation and P. australis were used more than expected.
• Female river otters used habitat for den and resting sites differently than what was expected. Agriculture was used less; water, riparian vegetation and P. australis were used more than expected.