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In subarctic waters winter may be the period during which seabirds face the greatest environmental and physiological pressures, yet seabird distribution during this time is poorly understood. Using at-sea surveys conducted in Prince William Sound, Alaska on research ‘ships of opportunity’ from November 2007 to March 2009, we investigated how seabird abundance and distribution vary within and between winters for three common seabird species with extensive ranges: common murre (Uria aalge), marbled murrelet (Brachyramphus marmoratus), and black-legged kittiwake (Rissa tridactyla). Due to a large proportion of zeros in the survey data, hurdle models were performed using generalized additive mixed models. Across the two winters, consistent temporal patterns in density and distribution were observed for all species. Common murre and marbled murrelet both increased in number in midwinter, while black-legged kittiwake decreased to very low numbers. Habitat association models revealed that common murre favored relatively protected waters while marbled murrelet favored inside bays and passages (which make up 45% of semi-protected waters) and areas of higher sea surface temperatures. Our results suggest that winter storms influenced seabird distribution, particularly in midwinter when temperatures were lowest and storms more frequent. This influence was greater than variables providing proxies for foraging opportunities, which were absent from selected models. Our study highlights the importance of considering species-specific temporal patterns throughout the non-breeding season to guide marine spatial planning that will fully address seabird conservation issues.
Fossils of Bassariscus, the ringtail (Carnivora, Procyonidae) are reported and described from the early Pliocene White Bluffs Local Fauna of the Ringold Formation, central Washington. The specimens, assigned to Bassariscus astutus, are larger than Miocene species of Bassariscus but show no apparent difference in size or dental characters from the living species B. astutus. The locality lies outside the geographical range of modern B. astutus and adds to evidence of less-extreme winter climate in the area during the early Pliocene.
Estuaries are biologically productive and diverse ecosystems that provide ecosystem services including protection of inland areas from flooding, filtering freshwater outflows, and providing habitats for fish and wildlife. Alteration of historic habitats, including diking for agriculture, has decreased the function of many estuarine systems, and recent conservation efforts have been directed at restoring these degraded areas to reestablish their natural resource function. The Nisqually Delta in southern Puget Sound is an estuary that has been highly modified by restricting tidal flow, and recent restoration of the delta contributed to one of the largest tidal salt marsh restorations in the Pacific Northwest. We correlated the response of nine major tidal marsh species to salinities at different elevation zones. Our results indicated that wetland species richness was not related to soil pore-water salinity (R2 = 0.03), but were stratified into different elevation zones (R2 = 0.47). Thus, restoration that fosters a wide range of elevations will provide the most diverse plant habitat, and potentially, the greatest resilience to environmental change.
Resting habitat used by fishers (Pekania pennanti) has been relatively well studied but information on the persistence of their resting structures over time is unknown. We selected for reexamination 73 of 195 resting structures used by by fishers in northwestern California and compared their condition on the date they were found with their condition 8.2–12.1 years later. Resting structures were classified into three functional groups: live trees, snags, and logs. Each group was classified further into structural stages of decay or decomposition. A total of 19.2% of resting structures changed structural stage over the assessment period, transitioning from one structural stage to another within or between groups. However, none of the structures declined in function to the point that they could not be used for resting. One tree jumped two functional groups, transitioning from a live tree to a log. Based on the rates of degradation that we observed, we recommend monitoring the fate of fisher resting structures every few decades. This will help us provide information about the loss rate of resting structures that, when combined with new information about the rate of cavity creation in trees and snags, will help us determine whether the forces of resting structure loss and gain are in dynamic equilibrium.
The primary prey species of mammal-eating killer whales in the Salish Sea, the inland waters of southern British Columbia and Washington state, have experienced dramatic increases in population abundances in the last 25 years. It is possible that changes in prey abundance over time have resulted in changes in predator spatial use, occurrence and group size. Focused studies of mammal-eating killer whale behavior in the area were undertaken from 1987–1993, and an extensive record of sightings with confirmed identifications was available from 2004–2010. Changes in occurrence across years, months, and subareas of the Salish Sea were examined as well as changes in group size and in the identity of specific matrilines using the area. Occurrence of mammal-eating whales increased significantly from 2004–2010 with different seasonal peaks compared to 1987–1993. Different matrilines occurred in different seasons, time periods, and subareas. Group size was larger in 2004–2010 than in 1987–1993. The whales may be increasing use of the area due to increasing prey abundance or an overall increase in the whale population size. Changes in seasonal patterns of occurrence and the increase in group size between the two periods could be due to increased prey diversity.
The diverse old-growth forests in Klamath region of northern California and southern Oregon provide valuable ecosystem services (e.g., maintaining watersheds, wildlife habitat, recreation), but may be vulnerable to a wide range of stressors, including invasive species, disrupted disturbance regimes, and climatic change. Yet our understanding of how forest structure in the Klamath region relates to the current physical environment is limited. Here we provide present-day benchmarks for old-growth forest structure across a climatic gradient ranging from coastal to dry interior sites. We established 16 large (1 ha) forest plots where all stems > 5 cm in diameter were identified to species and mapped. Climate across these sites was highly variable, with estimated actual evapotranspiration correlated to several basic measures of forest structure, including plot basal area, stem size-class inequality, tree species diversity and, to a lesser extent, tree species richness. Analyses of the spatial arrangement of stems indicated a high degree of non-uniformity, with 75% of plots showing significant stem clumping at small spatial scales (0 to 10 m). Downscaled predictions of future site water balance suggest changes will be dominated by rapidly increasing climatic water deficit (D, a biologically meaningful index of drought). While these plots give a picture of current conditions, continued monitoring of these stands is needed to describe forest dynamics and to detect forest responses to ongoing and future stressors.
The North American river otter, Lontra canadensis, is widely distributed throughout the Northern Hemisphere but has become increasingly rare in some areas due to trapping, hunting, and environmental pollutants. Thorough research has been done on coastal and inland populations but relatively less research has been done on estuarine otter populations. This study investigated the dietary patterns in river otters in the Snohomish River Estuary in northern Washington between October 2012 and May 2013. Solitary otters were observed during 66% of recordings by a remote camera at the most sampled latrine site; however, groups as large as five were recorded on camera. Fecal analysis indicated crustacean, found in 76% of samples, as the primary food source for this population during the sampled time period and location. These data are from a limited observation and therefore preliminary, but demonstrate a need for more comprehensive research in this population of otters.
Headwater and intermittent streams have traditionally been considered less biologically diverse than downstream perennial reaches. However, recent studies have highlighted the significant role that headwaters play in supporting regional aquatic biodiversity. Additionally, intermittent streams in the Pacific Northwest may be more diverse than similar streams in other regions. Here, we present a four-year biodiversity study of the John West Fork, an intermittent coastal headwater stream in northern California. It only flows for 5–7 months each year, but supports residual perennial pools during the summer dry season. Our goals are to describe the physical and biological settings of the John West Fork, document its aquatic biodiversity, and promote the use of it and similar streams as study systems. From 2009 to 2012, we sampled fish and invertebrates in riffles and pools during early summer (June) and in residual pools during late summer (late September/early October). We documented four vertebrate species (steelhead trout, coho salmon, California giant salamander, and Pacific chorus frog) and 159 aquatic invertebrate taxa. Steelhead trout were common each year, but coho salmon were present only in 2010 and 2011. Most invertebrate taxa were tolerant of stagnant pool conditions; only nine taxa were exclusive to flowing riffle habitats. Intermittent headwater streams similar to John West Fork are numerous along the west coast of North America. This great number of replicate systems and their tractability make them ideal for ecological studies, and their high biodiversity makes them deserving of consideration in local and regional conservation planning.
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