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Indirect climate effects on tree fecundity that come through variation in size and growth (climate-condition interactions) are not currently part of models used to predict future forests. Trends in species abundances predicted from meta-analyses and species distribution models will be misleading if they depend on the conditions of individuals. Here we find from a synthesis of tree species in North America that climate-condition interactions dominate responses through two pathways, i) effects of growth that depend on climate, and ii) effects of climate that depend on tree size. Because tree fecundity first increases and then declines with size, climate change that stimulates growth promotes a shift of small trees to more fecund sizes, but the opposite can be true for large sizes. Change the depresses growth also affects fecundity. We find a biogeographic divide, with these interactions reducing fecundity in the West and increasing it in the East. Continental-scale responses of these forests are thus driven largely by indirect effects, recommending management for climate change that considers multiple demographic rates.

Highly pathogenic avian influenza viruses (HPAIV) H5N1 clade 2.3.4.4b continue to have unprecedented global impacts on wild birds and mammals, with especially significant mortality observed in colonial surface-nesting seabirds and in some marine mammal species. In July of 2023 H5N1 HPAIV 2.3.4.4b was detected in Caspian terns nesting on Rat Island, Washington USA. An estimated 1,800–1,900 adult terns populated the breeding colony, based on aerial photographs taken at the start of the outbreak. On a near-weekly basis throughout July and August, we counted and removed carcasses, euthanized moribund birds, and collected swab and tissue samples for diagnostic testing and next-generation sequencing. We directly counted 1,101 dead Caspian tern adults and 520 dead chicks, indicating a minimum 56% loss of the adult colony population and potential impacts to reproductive success. Combining the observed mortality on Rat Island with HPAI-related Caspian tern deaths recorded elsewhere in Washington and Oregon, we estimate that 10–14% of the Pacific Flyway population was lost in the summer of 2023. Comparatively few adult Glaucous-winged gulls (hybrids) nesting on Rat Island died (~3% of the local population), although gull chick mortality was high. Sixteen harbor seals in the immediate or nearby area stranded during the outbreak, and H5N1 HPAIV was detected in brain and/or lung tissue of five seals. These cases are the first known detections of HPAIV in a marine mammal on the Pacific coast of North America. Phylogenetic analyses support the occurrence of at least three independent avian-mammalian virus spillover events (tern or gull to harbor seal). Whole genome sequencing indicated that H5N1 HPAIV may have been introduced to Washington from Caspian terns in Oregon. Ongoing monitoring and surveillance for H5N1 HPAIV in the marine environment is necessary to understand the epidemiology of this virus, assess conservation impacts to susceptible species, and provide support for data-driven management and response actions. [ABSTRACT FROM AUTHOR]

Investigating trophic relationships can be critical for understanding relationships between marine predators and their prey. DNA analysis of feces is used increasingly as a non-invasive method to uncover seabird dietary patterns across space and time. Tufted Puffins Fratercula cirrhata are listed as Endangered in the state of Washington (WA), USA, and reduced prey availability is thought to be a key factor in the species' decline. Recent information on Tufted Puffin diet is lacking, and present opportunities for direct diet observation are limited. We conducted a pilot study to characterize Tufted Puffin diet on Destruction Island, WA, in 2019 using DNA metabarcoding of feces from burrow entrances and from soil in nesting chambers. Smelt (Osmeridae) and rockfish (Scorpaenidae) were detected in all fecal samples, along with a variety of other fish taxa, squid, crab, and shrimp. Smelt was detected in most soil samples, as were a variety of other fish, crustaceans, and terrestrial insects. While DNA metabarcoding detected several taxa also identified in Tufted Puffin bill-loads in 2019, fecal and soil samples detected multiple taxa not identified in bill-loads. It appears that Tufted Puffin diet can be characterized using DNA metabarcoding, provided that fecal samples are of sufficient quality and that contamination is minimized. Amplifying prey DNA from soil samples opens opportunities for sampling burrows after breeding, which would minimize disruptions to study colonies. Future strategies to characterize Tufted Puffin diet could combine direct observation and DNA metabarcoding methods where possible and could focus on the latter methods where observation is difficult. These non-destructive and non-disruptive methods hold promise for characterizing the diet of other burrow-nesting species of conservation concern. [ABSTRACT FROM AUTHOR]

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.

Clinical metrics of baseline health in sentinel seabird species can offer insight into marine ecosystem dynamics, individual and population health, and assist in wildlife rehabilitation and conservation efforts. Protein electrophoresis is useful for detecting changes in acute phase proteins and immunoglobulin levels that may indicate subtle inflammatory responses and/or infectious disease. Serum biochemistry can highlight nutritional status, metabolic derangements, and organ injury and function. However, baseline values for such health parameters are largely unknown for many seabird species. Therefore, the objective of this study is to establish baseline clinical health reference intervals for serum protein electrophoresis, acute phase proteins including serum amyloid A and haptoglobin, and biochemistry parameters in the rhinoceros auklet (Cerorhinca monocerata), a key sentinel species in the North Pacific. From 2013 to 2019, 178 wild, apparently healthy breeding adult rhinoceros auklets were captured across four breeding colonies in British Columbia, Canada (Lucy Island, Pine Island, Triangle Islands, and SGang Gwaay) and from one colony in Washington, United States (Protection Island). Reference intervals were calculated for protein electrophoresis fractions and acute phase proteins (n = 163), and serum biochemistry (n = 35) following established guidelines by the American Society of Veterinary Clinical Pathology. Animals were also assessed for the presence of antibodies to the influenza A virus. Approximately 48% (70/147) of sampled birds were seropositive for influenza A virus, with a prevalence of 50% (6/12) in 2013, 75% (47/63) in 2014, and 24% (17/72) in 2019. This work provides clinical baseline health metrics of a key North Pacific sentinel species to help inform marine ecosystem monitoring, recovery, and rehabilitation efforts in the Pacific Northwest. [ABSTRACT FROM AUTHOR]

Understanding prey consumption patterns is critical to understanding the ways in which seabirds cope with a changing ocean. However, characterizing the dietary habitats of seabirds can be challenging. In this study, we investigated the diet of the Marbled Murrelet Brachyramphus marmoratus population that lives in waters off California, Oregon, and Washington, USA, using fecal DNA, custom metabarcoding, and high-throughput sequencing. Murrelets were captured at sea by dip-netting at night. Across this region, murrelets consumed highly diverse prey types including 17 fish species and 10 invertebrate species, in accord with previous work indicating the species' forage on a wide range of prey. Pacific Herring Clupea pallasii was the most common prey in Washington and Oregon (frequency of occurrence = 0.84 and 0.69, respectively), replaced by Northern Anchovy Engraulis mordax in California (frequency of occurrence = 0.77). In Oregon, where our sample size was sufficient, diet composition differed between the 2017 and 2018 breeding seasons, with an apparent decline in the proportional consumption of energy-dense prey. Common and energy-dense prey were consumed in equal proportions by males and females, perhaps because of foraging in the same habitat. Diet did not vary between breeders and non-breeders. Our study offers the first detailed report on the diet of adult Marbled Murrelets in waters where they are listed as Threatened by the US federal government. This indicates that managing fisheries and conserving spawning habitat for high-occurrence prey species could benefit murrelet populations. [ABSTRACT FROM AUTHOR]

In dozens of U.S. cities, more than one in five students now attend charter schools. Charter school expansion has fueled an increasingly energetic discussion among advocates: How large a share [...]