River otters (Lontra canadensis) are native to Nebraska but were extirpated by the early 1900s. River otters became reestablished in Nebraska following their reintroduction in the mid 1980s and early 1990s by the Nebraska Game and Parks Commission (NGPC). The species is currently listed as threatened in Nebraska. Despite the high profile of the reintroduction and the otters' role as a flagship species, relatively little is known about river otter ecology in Nebraska. Despite the high profile of the reintroduction and the otters' role as a flagship species, relatively little is know about river otter ecology in Nebraska.
In order to provide information for management, research was conducted to determine home range, habitat use, overnight movement distance, and annual survival of river otters in the central Platte River of Nebraska.
GoalsThis project is collecting home range and habitat use information on river otters along the big bend area of the Platte River using radio telemetry. Data collected, in conjunction with the results of an ongoing river otter health and reproductive survey and results from NGPC's annual otter bridge survey, will help to close existing information gaps and contribute to the creation of the Nebraska River Otter Management Plan and the Statewide Comprehensive Conservation Plan.
Eighteen river otters were trapped, implanted with telemetry transmitters, and tracked during 2006-2009. Researchers obtained 996 telemetry locations and constructed 13 annual home ranges. Male home ranges were larger than female home ranges. Habitat use was determined by comparing used versus available habitats using compositional analysis. Open water was used more than any other habitat type in all three comparisons tested.
Nineteen overnight movements were recorded (465 total telemetry locations) for four river otters during 2007–2008. Movements during January–February, when NGPC conducts winter bridge surveys, were lower than during the rest of the year. Annual survival was 100% as no river otter mortalities were detected during the study period.
River otters in the central Platte River select open water over other habitat types, exhibit reduced movements during winter months, and have high annual survival. This information will be used by NGPC to assess the status of river otters in Nebraska and direct management efforts for the species.
This project was completed with a thesis submission and successful defense during July 2012.
Read October 29, 2009 Scarlet article "Researchers hope poop project gets to bottom of river otter questions"
Read October 29, 2009 The Daily Nebraskan article "Researchers track otters by scat"