Representation of the Pacific Arctic seabird community within the Distributed Biological Observatory array, 2007–2015. (April 2019)

• Record Type: Journal Article
• Authors: Kuletz, Kathy J.; Cushing, Daniel A.; Osnas, Erik E.; Labunski, Elizabeth A.; Gall, Adrian E.
• Is Part Of: Deep sea research. Volume 162(2019)
• Page Start: 191
• Page End: 210
• Publication Date: 2019-04
• Subjects: Distributed Biological Observatory -- Pacific Arctic -- Seabird communities -- Seabird distribution -- Seabird species richness -- Bering Sea -- Chukchi Sea -- Beaufort Sea; Oceanography -- Periodicals; Ocean bottom -- Periodicals; Marine biology -- Periodicals; 551.46
• DOI: 10.1016/j.dsr2.2019.04.001
• Languages: English
• ISSNs: 0967-0645

Abstract

Abstract: An array of eight Distributed Biological Observatory (DBO) sites serve as long-term monitoring areas for three geographic regions: the northern Bering, eastern Chukchi, and Beaufort seas. The locations of the DBO sites were largely determined based on abundance and diversity of benthic invertebrates. It is not clear how well these fixed sampling sites can detect changes in processes and populations that operate over spatial scales that are 1–3 orders of magnitude greater than the areas sampled by the DBO sites. In this paper, we examine whether the DBO array provides a reasonable method by which to describe and monitor the distribution and community composition of seabirds in the eastern Pacific Arctic, and if it captures areas of high seabird abundance. We used vessel-based survey data totaling ∼115, 860 km of transects within the study area from July–October 2007–2015. We compared species richness, diversity, abundance, and community composition of seabirds among DBO sites and to the broader geographic regions. In general, the avifauna of DBO sites were representative of their respective surrounding region, although sampling effort in the Beaufort was limited. Species richness (totaling 63 species) was highest in the Bering region and lowest in the Beaufort region. Species diversity indices were similar among DBO sites and regions, except for exceptionally low diversity in the two easternmost DBO sites of the Beaufort region. Total seabird abundance was highest in and near Bering Strait, and dropped abruptly northward and eastward of Point Barrow. We used K-means cluster analysis to identify six community types across the entire study area, with five community types identified as having at least one numerically dominant species, and one community type defined by very low densities of a variety of species. Several community types were associated with major current systems (e.g. Anadyr Current, Alaska Coastal Current), and for two community types, breeding colony locations were also influential. Short-tailed shearwaters were the most abundant species in five of the eight DBO sites, and they were the numerically dominant species in a community that was represented from DBO 1 through DBO 6. Overall, variance in abundance was much greater by DBO site (or region) than by year for total birds and for seven of eleven taxa. Taxa with greater interannual variance than spatial variance were shearwaters and phalaropes (among regions), and murrelets (among DBO sites), all of which are late summer migrants to the study area, and glaucous gulls, a circumpolar species. The consistency in species' abundance by site indicates that DBO sites will be useful for monitoring seabirds in each region. As an array, the DBO sites captured major hotspots of seabird abundance as well as the seabird communities, except for the fulmar-dominated community in the outer Bering Shelf. However, all DBO sites will need to be surveyed to capture the full range of seabird communities in this study area. The Beaufort DBO sites require more survey coverage than currently achieved to fully evaluate their effectiveness to monitor changes in seabirds for that region.