Wildlife Research Division

Ottawa, Canada

Wildlife Research Division

Ottawa, Canada
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Vilchis L.I.,University of California at Davis | Vilchis L.I.,University of California at San Diego | Johnson C.K.,University of California at Davis | Evenson J.R.,Wildlife Research Division | And 5 more authors.
Conservation Biology | Year: 2015

Identifying drivers of ecosystem change in large marine ecosystems is central for their effective management and conservation. This is a sizable challenge, particularly in ecosystems transcending international borders, where monitoring and conservation of long-range migratory species and their habitats are logistically and financially problematic. Here, using tools borrowed from epidemiology, we elucidated common drivers underlying species declines within a marine ecosystem, much in the way epidemiological analyses evaluate risk factors for negative health outcomes to better inform decisions. Thus, we identified ecological traits and dietary specializations associated with species declines in a community of marine predators that could be reflective of ecosystem change. To do so, we integrated count data from winter surveys collected in long-term marine bird monitoring programs conducted throughout the Salish Sea-a transboundary large marine ecosystem in North America's Pacific Northwest. We found that decadal declines in winter counts were most prevalent among pursuit divers such as alcids (Alcidae) and grebes (Podicipedidae) that have specialized diets based on forage fish, and that wide-ranging species without local breeding colonies were more prone to these declines. Although a combination of factors is most likely driving declines of diving forage fish specialists, we propose that changes in the availability of low-trophic prey may be forcing wintering range shifts of diving birds in the Salish Sea. Such a synthesis of long-term trends in a marine predator community not only provides unique insights into the types of species that are at risk of extirpation and why, but may also inform proactive conservation measures to counteract threats-information that is paramount for species-specific and ecosystem-wide conservation. © 2014 The Authors.

Panitvong N.,Kasetsart University | Sumontha M.,Ranong Marine Fisheries Station | Konlek K.,Wildlife research division | Kunya K.,Nakhonratchasima Zoo
Zootaxa | Year: 2010

A new species, Gekko lauhachindai sp. nov. is described from Saraburi Province in central Thailand. It is a member of the mid-sized Gekko petricolus group and within this group it is probably most closely related to G. grossmanni Günther, 1994, G. scientiadventura Rösler et al., 2005, G. russelltraini Ngo et al., 2009, and G. takouensis Ngo & Gamble, 2010 with which it shares a similar dorsal pattern. The new species is distinguished from its congeners by its moderate size (SVL at least to 98 mm) and slender body, rostral participation in the nostril border, precloacal pores 12-14, femoral pores absent, dorsal tubercle rows 14, snout less than 1.5 times eye diameter, presence of "I" shaped rostral groove, interorbital scale rows 36-40, digit I and IV of pes with 13 and 13-15 enlarged subdigital scansors, respectively, and dorsal pattern of large bright spots dorsally that may be expanded to 5-6 whitish narrow cross bars intersected by a bright mid-dorsal dotted line from nape to sacrum. The new species is one of many recently described Southeast Asian geckos that appear to be restricted to limestone caves. It is the seventh species of Gekko known from Thailand and the third Gekko occurring in sympatry in the karst forests of Chalermphrakiat District, Saraburi Province, central Thailand. © 2010 Magnolia Press.

Pearson S.F.,Wildlife Research Division | Giovanini J.,Weyerhaeuser Company | Jones J.E.,Weyerhaeuser Company | Kroll A.J.,Weyerhaeuser Company
PLoS ONE | Year: 2015

Riparian ecosystems integrate aquatic and terrestrial communities and often contain unique assemblages of flora and fauna. Retention of forested buffers along riparian habitats is a commonly employed practice to reduce potential negative effects of land use on aquatic systems. However, very few studies have examined long-term population and community responses to buffers, leading to considerable uncertainty about effectiveness of this practice for achieving conservation and management outcomes. We examined short- (1-2 years) and long-term (∼10 years) avian community responses (occupancy and abundance) to riparian buffer prescriptions to clearcut logging silvicultural practices in the Pacific Northwest USA. We used a Before-After-Control-Impact experimental approach and temporally replicated point counts analyzed within a Bayesian framework. Our experimental design consisted of forested control sites with no harvest, sites with relatively narrow (∼13m) forested buffers on each side of the stream, and sites with wider (∼30m) and more variable width unharvested buffer. Buffer treatments exhibited a 31-44% increase in mean species richness in the post-harvest years, a pattern most evident 10 years post-harvest. Post-harvest, species turnover was much higher on both treatments (63-74%) relative to the controls (29%). We did not find evidence of local extinction for any species but found strong evidence (no overlap in 95% credible intervals) for an increase in site occupancy on both Narrow (short-term: 7%; long-term 29%) and Wide buffers (short-term: 21%; long-term 93%) relative to controls after harvest. We did not find a treatment effect on total avian abundance. When assessing relationships between buffer width and site level abundance of four riparian specialists, we did not find strong evidence of reduced abundance in Narrow or Wide buffers. Silviculture regulations in this region dictate average buffer widths on small and large permanent streams that range from ∼22-25 m. Guidelines for this region are within the range of buffers included in our study, in which we observed no evidence for avian species loss or for a decline in species abundance (including riparian associated species). © 2015 Pearson et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Pearson S.F.,Wildlife Research Division | Hodum P.J.,University of Puget Sound | Good T.P.,National Oceanic and Atmospheric Administration | Schrimpf M.,University of Washington | Knapp S.M.,Wildlife Research Division
Condor | Year: 2013

We present a prototype monitoring strategy for estimating the density and number of occupied burrows of burrow-nesting seabirds. We use data and management questions from Washington State as an example that can be applied to burrow-nesting seabirds at single- or multi-island scales. We also demonstrate how habitat assessments can be conducted concurrently. Specifically, we compared the density and occupancy of burrows of the Rhinoceros Auklet (Cerorhinca monocerata) at nesting colonies in the California Current and the Salish Sea and in the 1970s, 1980s, and today. We estimated 36 152, 1546, and 6494 occupied burrows on Protection and Smith islands (Salish Sea), and Destruction Island (California Current), respectively. Our estimates for the Salish Sea are 52% greater than those from the 1970s and 1980s, while that for the California Current is 60% less than that of 1975. This suggests that the Salish Sea population has increased, despite greater human effects on that ecosystem. However, some of the estimated changes between the periods could be the result of methodological and analytical differences. To address these issues we recommend an unbiased and representative sampling approach (stratified random) and an approach for optimally allocating the samples among strata within and among islands, depending on the scale of the question being addressed. Optimally allocating the sample would save a great deal of field effort; using this approach, we achieve relatively high power (>0.80) to detect moderate changes (20%) sampling hundreds of fewer plots than in a sample not optimally allocated. © The Cooper Ornithological Society 2013.

Good T.P.,National Oceanic and Atmospheric Administration | Pearson S.F.,Wildlife Research Division | Hodum P.,University of Puget Sound | Boyd D.,National Oceanic and Atmospheric Administration | And 2 more authors.
Marine Pollution Bulletin | Year: 2014

Organochlorine contaminants in upper trophic-level consumers inhabiting Puget Sound are consistently higher than in those species inhabiting other west coast locations. We analyzed persistent organic pollutants (POPs) in the six most common fish prey of rhinoceros auklets breeding on Protection Island (Puget Sound), Tatoosh Island (WA coast), and Destruction Island (WA coast). Wet-weight concentrations of POPs ranged widely (PCBs: 1.6-25.0. ng/g; DDTs: 0.2-56.0. ng/g; PBDEs:

Bromaghin J.F.,U.S. Geological Survey | Lance M.M.,Wildlife Research Division | Elliott E.W.,University of Alaska Anchorage | Jeffries S.J.,Wildlife Research Division | And 2 more authors.
Fishery Bulletin | Year: 2013

Harbor seals (Phoca vitulina) are an abundant predator along the west coast of North America, and there is considerable interest in their diet composition, especially in regard to predation on valued fish stocks. Available information on harbor seal diets, primarily derived from scat analysis, suggests that adult salmon (Oncorhynchus spp.), Pacific Herring (Clupea pallasii), and gadids predominate. Because diet assessments based on scat analysis may be biased, we investigated diet composition through quantitative analysis of fatty acid signatures. Blubber samples from 49 harbor seals captured in western North America from haul-outs within the area of the San Juan Islands and southern Strait of Georgia in the Salish Sea were analyzed for fatty acid composition, along with 269 fish and squid specimens representing 27 potential prey classes. Diet estimates varied spatially, demographically, and among individual harbor seals. Findings confirmed the prevalence of previously identified prey species in harbor seal diets, but other species also contributed significantly. In particular, Black (Sebastes melanops) and Yellowtail (S. flavidus) Rockfish were estimated to compose up to 50% of some individual seal diets. Specialization and high predation rates on Black and Yellowtail Rockfish by a subset of harbor seals may play a role in the population dynamics of these regional rockfish stocks that is greater than previously realized.

Schrimpf M.B.,University of Washington | Parrish J.K.,University of Washington | Pearson S.F.,Wildlife Research Division
Marine Ecology Progress Series | Year: 2012

Many productive ocean ecosystems are also highly variable, resulting in complex trophic interactions. We analyzed interannual patterns in the diet of a seabird, the common murre Uria aalge, in a region of high oceanographic productivity, the northern California Current, to investigate how these top predators adjust their chick provisioning to cope with environmental variability. Murres relied chiefly on Pacific herring Clupea harengus pallasi and surf smelt Hypomesus pretiosus to provision chicks, although they regularly returned 8 other fish taxa. Provisioning success was measured by the energy return rate to chicks, which in turn was disarticulated into energy per meal (quality) and meal delivery rate (quantity). Parents exhibited 'compensation' during 2 years in which smaller, low quality prey were returned more quickly than in years with normal (i.e. 'good') provisioning. Despite the increased delivery rate, energy return rates were still lower in 'compensation' vs. 'good' years. The lowest energy return rates occurred in 3 'poor' years, during which ocean productivity was also depressed. Our results suggest that murres in this system have the ability to shift provisioning strategies to deal with some variability in prey resources, but not when limited by exceptionally poor environmental conditions. © Inter-Research 2012.

Dieval H.,Groupe de Recherche en Ecologie Comportementale et Animale | Giroux J.-F.,Groupe de Recherche en Ecologie Comportementale et Animale | Savard J.-P.L.,Wildlife Research Division
Wildlife Biology | Year: 2011

Common eiders Somateria mollissima nest in colonies on islands of the St. Lawrence Estuary in Quebec, Canada. After hatching, attending females must reach suitable brood-rearing habitats while non-attending females and adult males must find appropriate moulting sites. The aim of our study was to determine the biotic and abiotic factors that influence the distribution of common eiders during the brood-rearing and moulting periods. We conducted biweekly surveys and recorded the number of ducks by age and sex in 2003 and 2004 at 68 sites along a 200-km stretch of the south shore of the St. Lawrence River. We further classified adult females according to the presence or absence of young. We evaluated human disturbance during the surveys and developed a sinuosity index describing shoreline protection. We determined the nature of the substrate and an estimate of food abundance for a subsample of sites (N = 38). At the scale of the estuary, common eiders did not distribute randomly but used the same sites in both years. Broods preferred mainland sites near nesting islands. Non-maternal females and males were located further east along the estuary, but their numbers were lower than expected based on the size of the breeding population, indicating that some birds undertake a moult migration outside of the area. In the eastern portion of our study area, densities of non-maternal females increased significantly as summer progressed. The distribution of common eiders was influenced by food abundance and type but was not related to our indices of human disturbance and shoreline protection. Males were associated with mussels, non-maternal females with both mussels and gammarids, while maternal females with ducklings were associated with periwinkles. Few of the sites used by common eiders along the south shore of the St. Lawrence Estuary are currently protected and measures should thus be taken to insure their conservation. © Wildlife Biology, NKV.

Pearson S.F.,Wildlife Research Division | Moore R.,Oregon State University | Knapp S.M.,Wildlife Research Division
Journal of Field Ornithology | Year: 2012

Improving the conservation status of rare and declining species often requires multiple strategies targeted at several vital rates. We report on one of several ongoing management actions intended to benefit the declining population of Streaked Horned Larks (Eremophila alpestris strigata). To improve Streaked Horned Lark fecundity, we employed predator exclosures (wire cages) around nests (N= 33 exclosed and 32 not exclosed) in 2009 and 2010 at two sites in Oregon and two in Washington with the goal of excluding larger birds, the primary lark nest predators. We found no statistically significant effect of exclosures on nest success. For exclosed nests, lower rates of nest predation (exclosed = 12%, unexclosed = 48%) were offset by higher rates of nest abandonment (exclosed = 27%, unexclosed = 0%). Nest abandonment was likely caused by a variety of factors including American Kestrels (Falco sparverius) perching on exclosures, and predation of adults associated with exclosed nests. Our results suggest that the current exclosure design does not improve Streaked Horned Lark fecundity and may negatively affect adult survival. To improve exclosure effectiveness, we recommend modifications that prevent kestrels from perching on exclosures and deny their access to the nest. We also recommend that modifications be applied in an adaptive management framework that includes close monitoring to assess their effectiveness, and subsequent adaptation that might include continued structural modification of exclosures or discontinued use on some or all sites. © 2012 The Authors. Journal of Field Ornithology © 2012 Association of Field Ornithologists.

Pearson S.F.,Wildlife Research Division | Knapp S.M.,University of Arizona
PLoS ONE | Year: 2016

Habitat selection that has fitness consequences has important implications for conservation activities. For example, habitat characteristics that influence nest success in birds can be manipulated to improve habitat quality with the goal of ultimately improving reproductive success. We examined habitat selection by the threatened streaked horned lark (Eremophila alpestris strigata) at both the breeding-site (territory) and nest-site scales. Larks were selective at both spatial scales but with contrasting selection. At the territory scale, male larks selected sparsely vegetated grasslands with relatively short vegetation. At the nestsite scale, female larks selected sites within territories with higher vegetation density and more perennial forbs. These nest-site scale choices had reproductive consequences, with greater nest success in areas with higher densities of perennial forbs. We experimentally manipulated lark habitat structure in an attempt to mimic the habitat conditions selected by larks by using late summer prescribed fires. After the burn, changes in vegetation structure were in the direction preferred by larks but habitat effects attenuated by the following year. Our results highlight the importance of evaluating habitat selection at spatial scales appropriate to the species of interest, especially when attempting to improve habitat quality for rare and declining species. They also highlight the importance of conducting restoration activities in a research context. For example, because the sparsely vegetated conditions created by fire attenuate, there may be value in examining more frequent burns or hotter fires as the next management and research action. We hope the design outlined in this study will serve as an integrated research and management example for conserving grassland birds generally. © 2016 Pearson, Knapp. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

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