Kelp forest loss and emergence of turf algae reshapes energy flow to predators in a rapidly warming ecosystem.

Climate change is decimating habitat-forming species in ecosystems around the world. Yet, the impacts of habitat loss on the energetics of the wider food web remain uncertain for many iconic ecosystems, including cold-water kelp forests. Here, we assessed how the loss of kelp forests and the subsequent proliferation of low-lying turf algae in the Gulf of Maine have altered the trophic niches of, and energy acquired by, predatory reef fishes.

Forecasting sea otter recolonization: insights from isotopic analysis of modern and zooarchaeological populations.

Retrospective datasets offer essential context for conservation by revealing species' ecological roles before industrial-era human impacts. We analysed isotopic compositions of pre-industrial and modern sea otters () to reconstruct pre-extirpation ecology and offer insights for management. Our study focuses on southeast Alaska (SEAK), where sea otters are recolonizing, and northern Oregon, where translocations are being considered.

Enhancing biodiversity: historical ecology and biogeography of the Santa Catalina Island ground squirrel, .

People have influenced Earth's biodiversity for millennia, including numerous introductions of domestic and wild species to islands. Here, we explore the origins and ecology of the Santa Catalina Island ground squirrel (SCIGS; ), one of only five endemic terrestrial mammals found on California's Santa Catalina Island. We synthesized all records of archaeological/palaeontological SCIGS, conducted radiocarbon dating and stable isotope analysis of the potentially earliest SCIGS remains and performed genetic analysis of modern SCIGS.

Tissue-specific carbon isotope patterns of amino acids in southern sea otters.

The measurement of stable isotope values of individual compounds, such as amino acids (AAs), has become a powerful tool in animal ecology and ecophysiology. As with any emerging technique, questions remain regarding the capabilities and limitations of this approach, including how metabolism and tissue synthesis impact the isotopic values of individual AAs and subsequent multivariate patterns. We measured carbon isotope (δC) values of essential (AA) and nonessential (AA) AAs in bone collagen, whisker, muscle, and liver from ten southern sea otters (Enhydra lutris nereis) that stranded in Monterey Bay, California.

After the mammoths: The ecological legacy of late Pleistocene megafauna extinctions.

The significant extinctions in Earth history have largely been unpredictable in terms of what species perish and what traits make species susceptible. The extinctions occurring during the late Pleistocene are unusual in this regard, because they were strongly size-selective and targeted exclusively large-bodied animals (i.e.

Late Pleistocene megafauna extinction leads to missing pieces of ecological space in a North American mammal community.

The conservation status of large-bodied mammals is dire. Their decline has serious consequences because they have unique ecological roles not replicated by smaller-bodied animals. Here, we use the fossil record of the megafauna extinction at the terminal Pleistocene to explore the consequences of past biodiversity loss.

Indigenous oyster fisheries persisted for millennia and should inform future management.

Historical ecology has revolutionized our understanding of fisheries and cultural landscapes, demonstrating the value of historical data for evaluating the past, present, and future of Earth's ecosystems. Despite several important studies, Indigenous fisheries generally receive less attention from scholars and managers than the 17th-20th century capitalist commercial fisheries that decimated many keystone species, including oysters. We investigate Indigenous oyster harvest through time in North America and Australia, placing these data in the context of sea level histories and historical catch records.

Intraspecific variation and energy channel coupling within a Chilean kelp forest.

The widespread importance of variable types of primary production, or energy channels, to consumer communities has become increasingly apparent. However, the mechanisms underlying this "multichannel" feeding remain poorly understood, especially for aquatic ecosystems that pose unique logistical constraints given the diversity of potential energy channels. Here, we use bulk tissue isotopic analysis along with carbon isotope (δ C) analysis of individual amino acids to characterize the relative contribution of pelagic and benthic energy sources to a kelp forest consumer community in northern Chile.

Reductions in the dietary niche of southern sea otters () from the Holocene to the Anthropocene.

The sea otter () is a marine mammal hunted to near extinction during the 1800s. Despite their well-known modern importance as a keystone species, we know little about historical sea otter ecology. Here, we characterize the ecological niche of ancient southern sea otters () using δC analysis and δN analysis of bones recovered from archaeological sites spanning ~7,000 to 350 years before present ( = 112 individuals) at five regions along the coast of California.

Historical ecology and the conservation of large, hermaphroditic fishes in Pacific Coast kelp forest ecosystems.

The intensive commercial exploitation of California sheephead () has become a complex, multimillion-dollar industry. The fishery is of concern because of high harvest levels and potential indirect impacts of sheephead removals on the structure and function of kelp forest ecosystems. California sheephead are protogynous hermaphrodites that, as predators of sea urchins and other invertebrates, are critical components of kelp forest ecosystems in the northeast Pacific.

The cost of reproduction: differential resource specialization in female and male California sea otters.

Intraspecific variation in behavior and diet can have important consequences for population and ecosystem dynamics. Here, we examine how differences in reproductive investment and spatial ecology influence individual diet specialization in male and female southern sea otters (Enhydra lutris nereis). We hypothesize that greater reproductive constraints and smaller home ranges of females lead to more pronounced intraspecific competition and increased specialization.