Loon abundance and behaviour over four decades at a remote ecological reserve on Haida Gwaii, British Columbia, Canada

Early studies (1976–1982) of the Drizzle Lake Ecological Reserve on Haida Gwaii, British Columbia focussed on the endemic Giant Threespine Stickleback (Gasterosteus aculeatus) and their predators. These surveys showed daily visits to the small lake (110 ha) by up to 59 adult non-breeding Common Loon (Gavia immer), an important stickleback predator and up to 19 breeding and non-breeding adult Red-throated Loon (Gavia stellata), which leave daily to forage in nearby marine waters. We continued loon surveys for 17 additional years (1983–1989, 2011–2020) and found that aggregations of non-breeding Common Loons occurred annually on the lake during July with maximum daily numbers of 78–83 individuals in 1987, 2018, and 2020 and a large increase from 2011 to 2020. We did not detect any relationship of these differences with the Pacific Decadal Oscillation but a significant inverse correlation with average wind speed. Average yearly numbers of Red-throated Loons declined by 50% from 1976 to 1989 and have remained low, with lowest numbers (<2) occurring in 2017. Two Red-throated Loon nesting territories on the lake were occupied from 1976 to 1995, with chicks occurring in 24 of 36 nests, but no successful nesting was observed on the lake over the last decade. The relative decline of Red-throated Loon in this reserve is similar to that reported in Arctic and Subarctic surveys of the species in the north Pacific and northern Europe. We discuss the implications for the evolutionary ecology of the sticklebacks and the conservation of the ecological reserve

Salmon-derived nitrogen in terrestrial invertebrates from coniferous forests of the Pacific Northwest

BACKGROUND: Bi-directional flow of nutrients between marine and terrestrial ecosystems can provide essential resources that structure communities in transitional habitats. On the Pacific coast of North America, anadromous salmon (Oncorhynchus spp.) constitute a dominant nutrient subsidy to aquatic habitats and riparian vegetation, although the contribution to terrestrial habitats is not well established. We use a dual isotope approach of δ(15)N and δ(13)C to test for the contribution of salmon nutrients to multiple trophic levels of litter-based terrestrial invertebrates below and above waterfalls that act as a barrier to salmon migration on two watersheds in coastal British Columbia. RESULTS: Invertebrates varied predictably in δ(15)N with enrichment of 3–8‰ below the falls compared with above the falls in all trophic groups on both watersheds. We observed increasing δ(15)N levels in our invertebrate groups with increasing consumption of dietary protein. Invertebrates varied in δ(13)C but did not always vary predictably with trophic level or habitat. From 19.4 to 71.5% of invertebrate total nitrogen was originally derived from salmon depending on taxa, watershed, and degree of fractionation from the source. CONCLUSIONS: Enrichment of δ(15)N in the invertebrate community below the falls in conjunction with the absence of δ(13)C enrichment suggests that enrichment in δ(15)N occurs primarily through salmon-derived nitrogen subsidies to litter, soil and vegetation N pools rather than from direct consumption of salmon tissue or salmon tissue consumers. Salmon nutrient subsidies to terrestrial habitats may result in shifts in invertebrate community structure, with subsequent implications for higher vertebrate consumers, particularly the passerines

Post-Reproductive Pacific Salmon, Oncorhynchus spp., as a Major Nutrient Source for Large Aggregations of Gulls, Larus spp.

On the Pacific coast of North America, the most abundant vertebrate visitors to estuaries and rivers during salmon migration are gulls, yet the utilization of salmon nutrients by these scavengers, and subsequent ecological impacts are not well documented. On two forested watersheds on the central coast of British Columbia, we tracked gull abundance during the spawning period for two consecutive years, and estimated consumption of post-reproductive salmon carcasses and eggs, as well as guano production. At Clatse River, gulls (Larus glaucescens, L. argentatus, L. thayerii, L. californicus, L. canus, L. philadelphia) consumed 13-26% of total salmon carcass biomass and 29-36% of all salmon eggs deposited in the system. At Neekas River, gulls consumed 11-19% of salmon carcass biomass and 7-18% of total salmon eggs. Local guano production over the 60-day period ranged from 600 kg to 1190 kg at Clatse and from 1200 kg to 2100 kg at Neekas River, and was distributed to marine, estuarine, freshwater and riparian habitats. The large aggregations of gulls and subsequent nutrient cycling observed on our study watersheds may represent a once widespread phenomenon that is now largely reduced due to recent declines in salmon populations

Endemism and Conservation of Sticklebacks in the Queen Charlotte Islands

"Dr. Peden's contribution was financed by the British Columbia Provincial Museum. Our work was supported by grants from the National Research Council of Canada to J. R. Nursall and G. E. E. Moodie.

Pacific Hagfish, Eptatretus stoutii, Spotted Ratfish, Hydrolagus colliei, and Scavenger Activity on Tethered Carrion in Subtidal Benthic Communities off Western Vancouver Island

The influence of pelagic carrion food falls on marine benthic scavenging communities was investigated at two depths (10 m, 50 m) in Barkley Sound, west Vancouver Island, British Columbia from 12 May to 4 June, 2003. A remotely operated vehicle (ROV) equipped with video cameras was used to monitor anchored carrion (15 kg pig leg) during daylight and darkness. The videos were subsequently analyzed for species diversity, abundance and the intensity of scavenging. At 10 m, Redrock Crab (Cancer productus) and Kelp Greenling (Hexagrammos decagrammus) dominated, while at 50 m, Spot Shrimp (Pandalus platyceros), Spotted Ratfish (Hydrolagus colliei) and Pacific Hagfish (Eptatretus stoutii) were the dominant species, most of which were nocturnal. Hagfish were the major consumers of the carrion and after 23 days, no soft tissues remained at 50 m while 40% remained at 10 m. Within 24 hours of the carrion deployment, two of eleven ratfish succumbed, probably due to the direct clogging effects of hagfish mucus on the respiratory apparatus of the ratfish. These field observations are consistent with laboratory results suggesting high efficacy of hagfish mucus in competitive interactions

The Genetic Architecture of Parallel Armor Plate Reduction in Threespine Sticklebacks

How many genetic changes control the evolution of new traits in natural populations? Are the same genetic changes seen in cases of parallel evolution? Despite long-standing interest in these questions, they have been difficult to address, particularly in vertebrates. We have analyzed the genetic basis of natural variation in three different aspects of the skeletal armor of threespine sticklebacks (Gasterosteus aculeatus): the pattern, number, and size of the bony lateral plates. A few chromosomal regions can account for variation in all three aspects of the lateral plates, with one major locus contributing to most of the variation in lateral plate pattern and number. Genetic mapping and allelic complementation experiments show that the same major locus is responsible for the parallel evolution of armor plate reduction in two widely separated populations. These results suggest that a small number of genetic changes can produce major skeletal alterations in natural populations and that the same major locus is used repeatedly when similar traits evolve in different locations

Do infants discriminate non-linguistic vocal expressions of positive emotions?

Adults are highly proficient in understanding emotional signals from both facial and vocal cues, including when communicating across cultural boundaries. However, the developmental origin of this ability is poorly understood, and in particular, little is known about the ontogeny of differentiation of signals with the same valence. The studies reported here employed a habituation paradigm to test whether preverbal infants discriminate between non-linguistic vocal expressions of relief and triumph. Infants as young as 6 months who had habituated to relief or triumph showed significant discrimination of relief and triumph tokens at test (i.e. greater recovery to the unhabituated stimulus type), when exposed to tokens from a single individual (Study 1). Infants habituated to expressions from multiple individuals showed less consistent discrimination in that consistent discrimination was only found when infants were habituated to relief tokens (Study 2). Further, infants tested with tokens from individuals from different cultures showed dishabituation only when habituated to relief tokens and only at 10–12 months (Study 3). These findings suggest that discrimination between positive emotional expressions develops early and is modulated by learning. Further, infants' categorical representations of emotional expressions, like those of speech sounds, are influenced by speaker-specific information

Diverse Ecological Pathways of Salmon Nutrients Through an Intact Marine-terrestrial Interface

Based on five years of field studies (1992, 1993, 1994, 1998, 2000), I quantified bi-directional movement of salmon nutrients through an estuary, stream, and old growth forest in a large protected reserve on Haida Gwaii, British Columbia. In 1993, when most data were collected, about 6000 Chum Salmon (Oncorhynchus keta) entered the river of which 22% of the total biomass of senescent carcasses were swept downstream into the estuary and were scavenged by gulls (n = 350) and subtidal invertebrates. Of the 3700 salmon (10 000 kg) transferred by American Black Bear (Ursus americanus) to the riparian zone and partially consumed along the 800 m of stream channel, 5070 kg of salmon tissues abandoned by the bears were scavenged by Northwestern Crows (Corvus caurinus; n = 200) but mostly (4100 kg) by calliphorid blowfly larvae resulting in larval densities averaging 240/m2 throughout the riparian zone. Total nitrogen input to the soils from the combined effects of bear and scavenger activity as well as carcass input was 18 g/m2 within 10 m of the stream channel. δ15N of foliar tissues of Lanky Moss (Rhytidiadelphus loreus), Red Huckleberry (Vaccinium parvifolium), Salal (Gaultheria shallon), and Western Hemlock (Tsuga heterophylla) ranged about 15‰ to 20‰ among adjacent microsites in each species, with higher values occurring in salmon carcass zones. Total nitrogen in foliar tissues ranged from 1% to 2.4% among microsites and was best predicted by positive correlations with foliar 15N values and secondarily by presence/absence of salmon carcasses. This is the first study to integrate estuarine to riparian ecological processes in the cycling of salmonid nutrients and identifies a range of ecological baselines that can inform the multiple restoration programs underway in degraded watersheds in the North Pacific

Host Patch Traits Have Scale‐Dependent Effects On Diversity In A Stickleback Parasite Metacommunity

Many metacommunities are distributed across habitat patches that are themselves aggregated into groups. Perhaps the clearest example of this nested metacommunity structure comes from multi‐species parasite assemblages, which occupy individual hosts that are aggregated into host populations. At both spatial scales, we expect parasite community diversity in a given patch (either individual host or population) to depend on patch characteristics that affect colonization rates and species sorting. But, are these patch effects consistent across spatial scales? Or, do different processes govern the distribution of parasite community diversity among individual hosts, versus among host patches? To answer these questions, we document the distribution of parasite richness among host individuals and among populations in a metapopulation of threespine stickleback Gasterosteus aculeatus. We find some host traits (host size, gape width) are associated with increased parasite richness at both spatial scales. Other patch characteristics affect parasite richness only among individuals (sex), or among populations (lake size, lake area, elevation and population mean heterozygosity). These results demonstrate that some rules governing parasite richness in this metacommunity are shared across scales, while others are scale‐specific

Range Expansion by Moose into Coastal Temperate Rainforests of British Columbia, Canada

Ranges of species are dynamic and respond to long-term climate change and contemporary effects such as habitat modification. We report here that moose (Alces alces) have recently colonized coastal temperate rainforests of British Columbia, Canada. Contrary to recent publications, field observations of moose and their sign, combined with their occurrence in wolf (Canis lupus) faeces, suggest that moose are now widespread on the coastal mainland and occur on least three islands. Traditional ecological knowledge (information accumulated by aboriginal peoples about their environment) suggests that colonization occurred during the mid 1900s, concomitant with logging of major watersheds that bisect the Coast Mountain Range. Range expansion by moose may have ecological consequences such as alteration of predator– prey dynamics and transmission of disease to native deer (Odocoileus hemionus)