Lake Abert BCS Number: 48-17
Total Page：16
File Type：pdf, Size：1020Kb
Oregon Coordinated Aquatic Bird Monitoring: Description of Important Aquatic Bird Site Lake Abert BCS number: 48-17 Site description author(s) Vernon Stofleth, Lakeview BLM District Kate Halstead, Field Technician, Klamath Bird Observatory Primary contact for this site Vernon Stofleth, Lakeview BLM District. Phone: (541) 947-6134. Email: [email protected] Site location (UTM) Datum: NAD 83, Zone: 10, Easting: 727446, Northing: 4722638. General description Boundaries and ownership Boundaries: Lake Abert Area of Critical Environmental Concern (ACEC) is located north of Valley Falls, Oregon. The southern boundary is the Rivers End Ranch just out of Valley Falls, Oregon and the northern boundary is the Tracy Land and Cattle Ranch. See Figure 1 for Google Earth (2009) map of Lake Abert. Ownership: The eastern and western boundaries are BLM-administered lands and State Highway 395 to the East. The 50,165 acre ACEC is BLM-administered land and is directly adjacent to private lands at the southern end (approximately 3 miles of shoreline) and private lands at the north end (approximately 8 miles of shoreline). See Figures 2 and 3 for BLM Lakeview District ownership maps. Water levels Abert Lake is dependent upon runoff from the Chewaucan River and only dries up 1 in 20 years. Description updated 4/29/2010 1 Focal species use and timing Secretive marsh birds, colonial nesters, ground based aquatic birds, and migrating shorebirds can all be seen in Abert Lake during April through August. This large alkaline lake is utilized by large numbers of migrating waterfowl and shorebirds (such as gulls, sandpipers, and phalaropes) that feed heavily on the endemic brine shrimp and brine flies that inhabit it. Focal Guild/Species Wintering Breeding Migration Secretive Marsh Birds Colonial Nesting Waterbirds Ground-based Aquatic Birds Migrating Shorebirds Present American White Pelican Barrow’s Goldeneye Black-necked Stilt Bufflehead Dusky Canada Goose Franklin’s Gull Greater Sandhill Crane Long-billed Curlew Snowy Egret Red-Necked Grebe Upland Sandpiper Western Snowy Plover Yellow Rail *the focal species for Oregon’s aquatic secretive marsh bird monitoring are PBGR, LEBI, AMBI, VIRA, SORA, YERA. Focal species observed within Abert Lake include: American Avocet American White Pelican Black-necked Stilt Bufflehead Eared Grebes Long-billed Curlew Northern Shovelers Pied-billed Grebe Sandhill Crane Snowy Egret Snowy Plover Yellow Rail Description updated 4/29/2010 2 Location of Type 1 and 2 habitat within the site Functional Group Type 1 Habitat Type 2 Habitat Ground Based Aquatic Perimeter of Lake Wet meadows Birds Secretive Marsh Birds Emergent Vegetation n/a Colonial Nesters Emergent Vegetation, open Perimeter of Lake water Migrating Shorebirds Shoreline Perimeter of Lake The 50,165 acre ACEC is comprised of 36,507 acres of wetland habitat and 13,658 acres of upland habitat. Within the wetland habitat type there are only 352 acres of Palustrine emergent, and 36,155 acres of open water Lacustrine habitat. The emergent habitat is comprised of Baltic rush, bulrush, cattails, and sedges. The Type 1 habitat is 352 acres of emergent Palustrine shoreline (kept wet during receding water due to the numerous freshwater springs and seeps). The Type 2 habitat is 13,658 acres of open water habitat. The private lands also contribute approximately 1,000 acres of emergent Palustrine Type 1 habitat. Access to Type 1 and 2 habitat and visibility/audibility of birds There is good public land access (hiking, vehicle, and boat) to the majority of the area. The public/private fringe areas can be surveyed with a spotting scope or boat. During high water years, the entire lake can be accessed by motorboat. Southern access to the western shore through Rivers End Ranch is not allowed, however access from the north is possible at this time through Tracy Land and Cattle Ranch. Access along State Highway 395, the east side of Abert Lake is good and there are a few areas where one can launch a small motorboat. The area is large (36,507 acres) but is comprised mainly of open water (36,155 acres) with very little emergent shoreline that either would not need to be surveyed or would be fairly easy to survey by boat. Approximately 1 year in 20 the entire lake dries up so surveys would only be needed around the seeps and springs. Audibility is a concern on the eastern boundary of Abert Lake because the boundary is State Highway 395. If surveys are conducted early in the morning when truck traffic is the lightest it would have the least impact. See Figure 4 for general road access to the area (Google Map 2009). Past and current surveys Waterfowl brood counts and shorebird counts have been conducted in the 1990’s and into the 2000’s with incidental sightings of secretive marsh birds noted, such as Pied- billed Grebes. USGS research focusing on American Avocet and Willet habitat use, movements and wetland connectivity was conducted in mid to late 1990’s within this and other (Summer Lake and Goose Lake) sites (Haig et al. 1998). Description updated 4/29/2010 3 Conservation issues . Brine shrimp harvest . Hydroelectric development . Wind Energy Conservation measures taken, in progress, or proposed . Federal designation of BLM Area of Critical Environmental Concern status . Lake Abert Area of Critical Environmental Concern Plan . ODFW / Lake Abert Brine Shrimp Management Plan Potential survey methods a. Description: The southern end of the lake, as well as, the northern end of the lake (private land) is best surveyed by boat or 4WD vehicle parked on adjacent BLM- administered land. The eastern and western edges of the lake have good vehicle access. Our waterfowl/shorebird surveys were conducted monthly in the 1990’s and are currently completed in conjunction with snowy plover inventories. b. Selection Bias: It is very difficult to get an accurate count for all waterfowl and shorebirds due to the large size of the lake. With our limited time and personnel constraints, we conduct waterfowl brood and shorebird trend counts on 10 or 12 areas of the Abert Lake and then extrapolate an estimate for the entire 36,507 acres. c. Measurement error and bias: It is fairly easy to see all of the birds on Abert Lake from a boat or vehicle; however, it is possible to double count birds due to movements. Manning and Hartley (2006) suggest that a ground-based survey for all aquatic birds would be valuable, and might be able to be conducted by volunteers. Whether an aerial waterfowl survey would be beneficial has yet to be determined. Potential pilot studies Description updated 4/29/2010 4 Literature cited Bureau of Land Management. Lakeview District. http://www.blm.gov/or/districts/lakeview/index.php. Accessed October 10, 2008. Bureau of Land Management, Lakeview District ownership map. http://www.blm.gov/or/districts/lakeview/images/LakeviewDetailedMap.jpg. Accessed March 20, 2009. Google Earth version 5.0. Image: Lake Abert. Accessed March 20, 2009. Google Map. 2009. Map of Lake Abert, Oregon. http://maps.google.com/maps?ll=42.613793,-120.25267&z=11&t=h&hl=en. Accessed March 20, 2009. Haig, S. M., D. W. Mehlman, and L. W. Oring. 1998. Avian movements and wetland connectivity in landscape conservation. Conservation Biology 12:749-758. Manning, Ann and Laura Hartley. March 2006. Important sites for aquatic birds in Eastern Oregon. Version 2.0. Description updated 4/29/2010 5 Figure 1: Google Earth (2009) map of Lake Abert. Description updated 4/29/2010 6 Figure 2: BLM Lakeview District ownership map. The red box indicates Lake Abert. Description updated 4/29/2010 7 Figure 3: BLM ownership map provided by Vern Stofleth. Description updated 4/29/2010 8 Figure 4: Google Map (2009) road view of Lake Abert. Description updated 4/29/2010 9 .