Marine bird colony and at-sea distributions along the Oregon coast: Implications for marine spatial planning and information gap analysis (original) (raw)
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Planning for Biodiversity: Bringing …, 2005
The coastal beach-dune ecosystem in California supports two federally listed threatened or endangered species: California least tern (Sterna antillarum browni) and western snowy plover (Charadrius alexandrinus nivosus). This ecosystem has become highly stressed due to shoreline development, invasion of exotic plants, beach stabilization, and heavy recreational use. Least tern populations have increased significantly since the 1980s. Snowy plover populations, however, show continued decline along California's coast. Management practices to protect least tern nesting colonies appear to be successful for terns but do not offer protection for plovers. More research is needed to monitor reproductive success and survival of snowy plovers in order to improve management practices and preservation of nesting areas. Impacts to estuarine ecosystems have been severe and include loss, degradation, and fragmentation. The most imperiled species within this system is the endangered lightfooted clapper rail (Rallus longirostrus levipes). Rail populations have ranged from a low of 142 pairs in 1985 to a high of 325 pairs in 1996 during the 22-year period they have been monitored. Most alarming is that only one estuary consistently supports more than 50 percent of California's rails, and only three sites support more than 80 percent. Although Belding's savannah sparrow (Passerculus sandwichensis beldingi) is not federally listed as endangered, populations in estuaries are stable or declining, but monitoring is erratic at best. Belding's savannah sparrows are area-sensitive, and reproductive success appears to be low in fragmented marshes. Research on productivity and survival of rails and sparrows is needed. Habitat enhancement and creation should be the highest priority for beach and estuarine birds as well as migratory shorebirds, but predator management and restrictions on recreation beach use are also necessary.
Long-And Short-Term Factors Affecting Seabird Population Trends in the California Current System
We analyzed trends in abundance of the most abundant marine bird species in the northern California Current System (CCS) during the upwelling season (May-June) over a 22-year period 1986-2007. Standardized seabird survey data were collected during annual cruises that ranged from Bodega Bay (38.32° N) to Cypress Point (35.58° N), and within this latitudinal range from the coast to the bottom of the continental slope (3000-m isobath). Indices of large-scale (basin-wide), regional (CCS), and local (study area) oceanographic data were used to characterize the response of seabird densities (number km-2) to environmental variability. The study occurred during a period of major fluctuations of El Niño-Southern Oscillation conditions (ENSO), and longer-term Pacific Decadal Oscillation variability (PDO). We related variation in species' abundance, with three seasonal lags: Late Winter (January-February); Early Spring (March-April); and Late Spring (May-June), to a suite of physical ocean and climate factors: Multivariate ENSO Index, PDO, coastal upwelling indices and sea-surface temperature. We detected cyclical trends in the abundance of the Black-footed Albatross (Phoebastria nigripes), and decreasing trends for Sooty Shearwater (Puffinus griseus), Pigeon Guillemot (Cepphus columbus), Rhinoceros Auklet (Cerorhinca monocerata), Cassin's Auklet (Ptychoramphus aleuticus), and Western Gull (Larus occidentalis) in the study area. A decrease in Ashy Storm-petrel (Oceanodroma homochroa) numbers may have been related to a loss of nesting habitat. No long-term pattern was evident in the numbers of Northern Fulmar (Fulmarus glacialis), Pink-footed Shearwater (P. creatopus), Leach's Storm-Petrel (O. leucorhoa), Common Murre (Uria aalge), Red Phalarope (Phalaropus fulicarius), Brandt's Cormorant (Phalacrocorax pennicillatus), Brown Pelican (Pelecanus occidentalis), and Sabine's Gull (Xema sabinii). Species varied in the degree to which remote versus local environmental factors explained annual variation in numbers. We hypothesize that decreasing trends, and even some of the short-term variability, was related to changes in ocean productivity and food availability. On the other hand, increasing trophic competition from baleen whales, which as suggested by a step-like pattern of population increase apparently rediscovered the study area where not long ago they had been harassed by whalers, may have been involved in some of the seabird trends as well; also involved likely were changes in characteristics of nesting grounds. Overall, our study points to the complexity of marine species' responses, particularly among far-ranging seabirds, to variation in the physical attributes of their habitat, which are in turn affected by remote and local climatic forces operating at multiple temporal scales.
The Condor, 2013
The future web presentation is intended to offer a venue for updating, improving, and refining the material presented in the Puget Sound Science Update. Suggested amendments and additions are presented as "content pending review" on each page when an editor, perhaps working with a collaborating author, has developed some new content that has not yet been formally adopted for incorporation into the section. As "content pending review," this content should not be cited or should be cited in a way that makes clear that it is still in preparation.
Coastal inlets as strategic habitat for shorebirds in the southeastern United States
2008
The purpose of this technical note is to bring together information from the International Shorebird Surveys (ISS) to demonstrate shorebirds' keystone-use of inlet habitats on marine coasts as compared to other coastal habitats in the southeastern United States including North Carolina, South Carolina, Georgia and Florida. Many inlets in the U.S. are affected by activities regulated by the U.S. Army Corps of Engineers (Corps). The goal of this Technical Note is to raise awareness of the importance of inlet habitats to coastal wildlife, including several species of shorebirds in the highest categories of conservation concern. This summary is largely based on an evaluation and presentations made at a workshop coordinated by American Bird Conservancy (ABC) working with the Corps of Engineers (Corps), held February 1-4, 2005 at Jekyll Island, Georgia (Guilfoyle et al. 2006; http://el.erdc.usace.army.mil/dots/coastalbirds.html). The ERDC and ABC hosted a series of three workshops dealing with coastal Corps activities and bird conservation. The Jekyll Island workshop covered the South Atlantic Coast, essentially from the Virginia-North Carolina border to south Florida. Subsequent workshops covered the North Atlantic and the Gulf Coasts. Workshop objectives were to expand capabilities of the Corps to contribute to various bird conservation plans, to make the bird conservation community aware of opportunities that exist through working with the Corps, to address and hopefully reduce some areas of conflict, and to improve interagency and organization cooperation for bird conservation in these coastal regions. This report, which provides guidance on how to create and manage dredged-material islands as earlysuccessional bird habitat, supports the objectives and was funded from a research work unit under the Corps of Engineers Dredging Operations and Environmental Research (DOER) program titled, "Reducing conflicts between coastal engineering projects and bird habitat needs." (http://el.erdc.usace.army.mil/dots/coastalbirds.html).
The California Current Marine Bird Conservation Plan
2005
The coastal and offshore areas of the California Current region provide a variety of feeding, roosting, and nesting habitat for seabirds. The abundant food in the California Current, resulting from high ocean primary productivity, attracts millions of seabirds that breed and/or migrate throughout this region annually, with the non-breeders outnumbering the breeders year-round (1, 2). Marine habitat characteristics and "quality" vary spatially and temporally, within and between seasons, years, and decades. Naturally occurring climate cycles in the world's oceans and atmosphere operate at several scales and strongly influence the CCS and, therefore, the ocean habitats that seabirds depend on for their survival, including habitat-specific productivity and predator-prey relationships. While the mechanisms of climate change are not well understood, it seems clear that climate cycles and change in ocean habitats, prey availability, and prey quality are critically linked to changes in seabird demography. In this section we summarize both terrestrial and marine habitat used by seabirds for breeding, roosting, and feeding in the CCS region. Oceanographic and atmospheric processes leading to marine climate variability on multiple temporal scales, and the response of seabirds to this variability, are discussed in detail in Chapter 5. 3.1 TERRESTRIAL HABITAT (A1). General Habitat Description The coastal and offshore areas of the West Coast provide a variety of roosting and nesting habitat, including islands, rocks, cliffs, headlands, beaches, estuaries, and even humanmade structures such as bridges, dikes, dredge spoil islands, jetties, and breakwaters. Islands, however, are disproportionately important sites for roosting and nesting. There are numerous islands off the west coast of North America, several of which contain seabird colonies exceeding 100,000 breeding birds. Numerous bays and estuaries along the mainland coast also provide critical habitat for many seabird species. The largest of these are Puget Sound in northern Washington, the Columbia River estuary on the border between Oregon and Washington, and San Francisco Bay in California. These protected coastal areas provide important breeding habitat, especially for coastal terns and gulls. East Sand Island in the Columbia River estuary supports the largest Caspian Tern colony in the world and the largest Doublecrested Cormorant colony in the Pacific. a. Islands-Islands, by their very nature, are isolated and typically provide seabirds with a protected habitat where they can breed and roost with little danger and few disturbances. The largest seabird colonies and the vast majority of breeding seabirds are found on islands, especially on those that are small to medium-sized. Islands are quite variable and have defining features that affect the species and number of seabirds that utilize them, such as size, shape, height, geological composition, micro-habitat characteristics, distance from shore, distance to feeding areas, presence or absence of soil, extent and depth of soil, plant communities, animal communities, and history of bird use. The smaller islets and rocks often support larger numbers of seabirds. Smaller islands are often uninhabited and free of mammalian predators such as rats, cats, dogs, foxes, and coyotes, although this is not always the case. Included in the island category, but unique, are the low islands found in bays and estuaries. These islands form naturally when sediments fall out of suspension in the slower moving waters of the estuary. They are much more dynamic in shape, size, and composition than the rocky, marine islands and in a natural system islands appear, disappear, and continually change shape. Scoured by 1. Only the eastern 24% of Santa Cruz Island is included in the National Park, the western 76% is owned and managed by The Nature Conservancy
Key seabird areas in southern New England identified using a community occupancy model
Marine Ecology Progress Series, 2015
Seabirds are of conservation concern, and as new potential risks to seabirds are arising, the need to provide unbiased estimates of species' distributions is growing. We applied community occupancy models to detection/non-detection data collected from repeated aerial striptransect surveys conducted in 2 large study plots off southern New England, USA; one off the coast of Rhode Island and the other in Nantucket Sound. A total of 17 seabird species were observed at least once in each study plot. We found that detection varied by survey date and effort for most species and the average detection probability across species was less than 0.4. We estimated the influence of water depth, sea surface temperature, and sea surface chl a concentration on species-specific occupancy. Diving species showed large differences between the 2 study plots in their predicted winter distributions, which were largely explained by water depth acting as a stronger predictor of occupancy in Rhode Island than in Nantucket Sound. Conversely, similarities between the 2 study plots in predicted winter distributions of surface-feeding species were explained by sea surface temperature or chlorophyll a concentration acting as predictors of these species' occupancy in both study plots. We predicted the number of species at each site using the observed data in order to detect 'hot-spots' of seabird diversity and use in the 2 study plots. These results provide new information on detection of species, areas of use, and relationships with environmental variables that will be valuable for biologists and planners interested in seabird conservation in the region.
Colonial-nesting Seabirds in the Chesapeake Bay Region: Where Have We Been and Where Are We Going?
Waterbirds, 2007
Over the past one hundred years, dramatic changes have taken place in populations of colonial-nesting seabirds that breed within Chesapeake Bay and the Maryland-Virginia coastal region. Populations of species that were decimated by extensive market hunting in the late nineteenth century recovered, additional species colonized the region and in the past ten years many species have declined. During 2003, over 72,000 pairs of seabirds of thirteen species bred within the region. Breeding population sizes are presented and population trends evaluated based on benchmark census information from 1977 and regional censuses compiled during 1993 and 2003 by the states of Maryland and Virginia. Since the 1970s, Brown Pelicans ( Pelicanus occidentalis ) and Double-crested Cormorants ( Phalacrocorax auritus ) expanded into the region and now represent six percent of the seabird guild. Gull populations have exhibited important changes and have affected other seabird species. Significant population declines have occurred in Black Skimmers ( Rynchops niger ), Gull-billed Terns ( Sterna nilotica ), Royal Terns ( Sterna maxima ), and Common Terns ( Sterna hirundo ). Since 1993, populations of ten of thirteen seabird species have declined, many significantly. Conservation challenges for seabird species in the region include: 1) habitat change and loss as a result of sea-level rise, 2) increasing mammalian predator populations, 3) competition for colony sites, 4) human infrastructure conflicts, and 5) changing fisheries populations and harvest. Conserving and managing colonial-nesting seabirds in the coming decades as the human population continues to increase in the mid-Atlantic region will present significant challenges to future generations.
Tracking data of marine predators are increasingly used in marine spatial management. We developed a spatial data set with estimates of the monthly distribution of 6 pelagic seabird species breeding in the Northeast Atlantic. The data set was based on year-round global location sensor (GLS) tracking data of 2356 adult seabirds from 2006−2019 from a network of seabird colonies, data describing the physical environment and data on seabird population sizes. Tracking and environmental data were combined in monthly species distribution models (SDMs). Crossvalidations were used to assess the transferability of models between years and breeding locations. The analyses showed that birds from colonies close to each other (< 500 km apart) used the same nonbreeding habitats, while birds from distant colonies (>1000 km) used colony-specific and, in many cases, non-overlapping habitats. Based on these results, the SDM from the nearest model colony was used to predict the distribution of all seabird colonies lying within a speciesspecific cutoff distance (400−500 km). Uncertainties in the predictions were estimated by cluster bootstrap sampling. The resulting data set consisted of 4692 map layers, each layer predicting the densities of birds from a given species, colony and month across the North Atlantic. This data set represents the annual distribution of 23.5 million adult pelagic seabirds, or 87% of the Northeast Atlantic breeding population of the study species. We show how the data set can be used in population and spatial management applications, including the detection of population-specific nonbreeding habitats and identifying populations influenced by marine protected areas.