Landbird Trends in National Parks of the North Coast and Cascades Network, 2005–12
Saracco JF, Holmgren AL , Wilkerson RL, Siegel RB, Kuntz RC, Jenkins KJ, Happe PJ, Boetsch JR, Huff MH. 2014. Landbird Trends in National Parks of the North Coast and Cascades Network, 2005–12. U.S. Geological Survey (USGS) Open-File Report. 2014–1202. National Park Service. U.S. Geological Survey, Reston, Virginia
National parks in the North Coast and Cascades Network (NCCN) can fulfill vital roles as refuges for bird species dependent on late-successional forests and as reference sites for assessing the effects of land-use/land-cover changes on bird populations throughout the Pacific Northwest. Long-term monitoring of landbirds in the NCCN provides information that can inform decisions about park management issues such as visitor impacts, fire management, and effects of introduced species. In 2005, the NCCN began implementing a network-wide Landbird Monitoring Project as part of the NPS Inventory and Monitoring Program. In this report, we discuss 8-year trends (2005–12) of bird populations in the NCCN, based on a sampling framework of point counts established in three large wilderness parks (Mount Rainier, North Cascades, and Olympic National Parks), 7-year trends at Lewis and Clark National Historical Park (sampled in 2006, 2008, 2010, and 2012), and 5-year trends at San Juan Island National Historical Park (sampled in 2007, 2009, and 2011). Our analysis encompasses a fairly short time span for the long-term monitoring program. The first 2 years (2005 and 2006) were implemented as a pilot study that included a small subset of transects. The subsequent 6 years (2007–12) represent one cycle through 5 years of alternating transect panels in the large parks, with the first of five alternating panels revisited for the first time in 2012. Of 204 transects in the six sampling panels in the large parks, only 68 (1/3) have thus been eligible for revisit surveys (34 during every year after 2005 and an additional 34 in 2012) and contribute to current trend estimates. We therefore initiated this analysis with a primary goal of testing analytical procedures rather than detecting trends that strong enough to drive conservation or management decisions. We expect aggregated trend detection results may change substantially over the next several years as number of transects with revisit histories triples and spatial dispersion of transects contributing to trend estimates improves. Meanwhile, caution should be exercised in interpreting the importance of trends as individual years can have large influences on the direction and magnitude of trends in a time series of such limited duration (and limited numbers of repeat visits at the small parks). Nevertheless, we estimated trends for 43 species at Mount Rainier National Park, 53 species at North Cascades National Park Complex, and 41 species at Olympic National Park. Of 137 park-species combinations (including combined-park analyses), we found 16 significant decreases (12%) and five significant increases (4%). We identify several limitations of the current analytical framework for trend assessment but suggest that overall sampling design is strong and amenable to analysis by more recently developed model-based methods. These could provide a more flexible framework for examining trends and other population parameters, as well as testing hypotheses that relate the distribution and abundance of species to environmental covariates. A model-based approach would allow for modeling various components of the detection process and analyzing observations (detection process), population state (occupancy, population size, density), and change (trend, local extinction and colonization rates turnover) simultaneously. Finally, we also evaluate operational aspects of NCCN Landbird Monitoring Project, and conclude that our robust, multi-party partnership is successfully implementing the project as envisioned.
- Type
- Published Report
- Authors
- Saracco, James; Holmgren, Amanda; Wilkerson, Robert; Siegel, Rodney; Kuntz, Robert; Jenkins, Kurt; Happe, Patti; Boetsch, John; Huff, Mark
- Date of Issue
- 2014-09
- Publisher
- National Park Service
- Units
- LEWI , MORA , NOCA , OLYM , SAJH
- Keywords
- Abundance, AIC, Akaike’s Information Criterion, alternating panel, American Camp, American crow, American Robin, annual panel, Avian, Band-tailed Pigeon, Biology, Bird, BirdTrend, brown creeper, Cassin’s Vireo, CDS, conventional distance sampling, dark-eyed junco, Density, Detectability, distance-detectability model, Distribution, English Camp, Golden-crowned Kinglet, Gray Jay, Hairy Woodpecker, Hermit Thrush, landbird monitoring, Lewis and Clark National Historical Park, Monitoring, Mount Rainier National Park, NCCN, NCCN synthesis report, North Cascades National Park Complex, North Coast and Cascades Network, Northern Flicker, Observation, Olive-sided Flycatcher, Olympic National Park, Pacific wren, Point Count, Presence, R software, red crossbill, Red-breasted Sapsucker, San Juan Island National Historical Park, Song Sparrow, Swainson’s Thrush, Townsend’s Warbler, Transect, Trend, Vaux’s Swift, Western tanager
- Subjects
- Ecological Framework: Biological Integrity | Focal Species or Communities | Birds