Introduction
The Seton Powerhouse Restoration Site was built in 2006, incorporating the Lillooet Naturalist Society, Cayoose Indian Band, and BC Hydro. In 2010, the St’at’imc name Sàt´atqwa7 was established. BC Hydro has supplied the majority of the funding through its Bridge Coastal Restoration Program and Fish and Wildlife Compensation Program.
The original purposes were an enhancement of the site for wildlife values and stewardship as well as simultaneous preservation as a recreational area for Lillooet residents and visitors. Restoration work involved removing invasive, non-native plants and replacing them with native species, installing vehicle traffic obstructions to minimize disturbance to riparian areas, and other anthropological disturbance. These restoring measures resulted in a big advance concerning the status of current riparian areas and the development of an upland sagebrush-dominated ecosystem. Wildlife trees were installed to increase the attractivity to cavity-nesting birds, bats and alternative wildlife use.
Despite the improvement concerning recreational use of the environment over the last several years, wildlife’s benefit of the project’s treatments has not been able to be approved.
The essence of the report was to summarize patterns of diurnal breeding birds at the Powerhouse and compare the results in contrast to three control sites established in the Seton-Fraser drainage.
Commonly, birds are an effective indicator on how environmental conditions are changing through time. They provide information about large-scale alterations such as climate change, but also respond to local factors, for example habitat changes caused by fires, insect-defoliation, new predators and peculiarly, direct anthropological disturbances.
Study Area and Methods
The study was implemented on the sides of the Fraser and Seton, near Lillooet, BC. Due to a rainshadow effect (Lee), the climate is semi-arid and the summers rather hot, whereas the winters are are cool and wet.
The Powerhouse site is located along the shores of the Fraser River Basin, which serves as a migration route for a variety of birds taking a north-south oriented journey. On the other hand, the Seton river funnels birds with a more coastal origin into the areas. The Powerhouse site occurs at the juncture of the two waterbodies. In order to contrast avian diversity and abundance of the waters, three control stations were established nearby.
The methods used for documenting the different species involved point counts and encounter transects.
Point counts are often used for assessing avian diversity and abundance. Over a certain amount of time and at a fixed station, an observer records all birds both heard and seen in a consistent fashion. The set amount of time for the surveys was five minutes. Furthermore, the distances of the detections were recorded, provided that they were located within a 75-metre contour.
In total, six point count stations were established (three at the Powerhouse site and three on geographically separated control sites).
In addition to this, encounter transects were applied. They consist of walking slowly on a previously defined 1.7 km route within the critical riparian habitat, observing and listening to the birds. This procedure gives additional information about habitat use, breeding evidence and other salient data. Even though this survey is not as thorough as point counts, it yields more species and further information.
Results
Surveys were implemented in June and July 2011, conducting the two areas with their three tracking points each as equally as possible.
At the Powerhouse, breeding bird diversity was significantly higher than at the control sites. The documenting method success varies for the locations, as encounter transects tracked more species in the Powerhouse, whereas the point counts method detected more species at the control sites.
Discussion
Significant differences between the Powerhouse and control sites have been detected both concerning diversity and species composition. Only a few species were found in both areas, which may be because of habitat dissimilarities such as the different amount of conifers.
Recommendations
The project was set to be continued during 2012 to get a bigger insight in breeding bird activity in mentioned areas. Furthermore, an analysis of breeding birds was to be completed over a five year period after evaluating the results of 2012’s study.
- Source Kenneth G. Wright. December 2011. Breeding Songbird Monitoring at the Seton Powerhouse Restoration (Sàt´atqwa7) Site 2011 Summary Report. Available at : http://www.env.gov.bc.ca/wildlife/wsi/reports/4998_WSI_4998_RPT_BIRD.PDF [Accessed 03/2021].