Katherine Sarah Christie

• Ph.D.
• Researcher at Alaska Department of Fish and Game, Anchorage, United States

Climate change is leading to a species redistributions. In the tundra biome, many shrub species are expanding into new areas, a process known as shrubification. However, not all tundra shrub species will benefit from warming. Winner and loser species (those projected to expand and contract their ranges, and/or those that have increased or decreased...

Drones, or unoccupied aircraft systems (UAS), can transform the way scientific information on wildlife populations is collected. UAS surveys produce accurate estimates of ground-nesting seabirds and a variety of waterbirds, but few studies have examined the trade-offs of this methodology for counting cliff-nesting seabirds. In this study, we examin...

Many populations of long‐distance migrant shorebirds are declining rapidly. Since the 1970s, the lesser yellowlegs (Tringa flavipes) has experienced a pronounced reduction in abundance of ~63%. The potential causes of the species' decline are complex and interrelated. Understanding the timing of migration, seasonal routes, and important stopover an...

Many populations of long-distance migrant shorebirds are declining rapidly. Since the 1970s, the Lesser Yellowlegs (Tringa flavipes) has experienced a pronounced reduction in abundance by ~63%. The potential cause(s) of the species’ decline are complex and interrelated, yet understanding the timing of migration and seasonal routes used by this spec...

Small mammals are under‐represented in conservation research relative to other mammals. We assessed the conservation status of 36 small mammal species in Alaska, USA using the Alaska Species Ranking System (ASRS). We also surveyed taxonomic experts to identify threats, conservation actions, and research priorities for five small mammal species of h...

Shorebirds have experienced a precipitous reduction in abundance over the past four decades. While some threats to shorebirds are widespread (e.g., habitat alteration), others are regional and may affect specific populations. Lesser Yellowlegs (Tringa flavipes) are long-distance migrants that breed across the North American boreal biome and have de...

In this study, we investigated how Little Brown Myotis (Myotis lucifugus), North America's northernmost bat species, adjusted to variable spring and autumn conditions and very little darkness during the boreal summer. We recorded bat activity around Anchorage and the lower Matanuska-Susitna Valley, Alaska. Initiation of bat activity in the spring v...

The Lesser Yellowlegs (Tringa flavipes) is a migratory shorebird species that has experienced a precipitous population decline. The factors governing this decline are complex and may correspond to habitat traits and migratory dynamics. Recent advancements in GPS telemetry have allowed for a precise description of migratory patterns to interpret the...

The Arctic is entering a new ecological state, with alarming consequences for humanity. Animal-borne sensors offer a window into these changes. Although substantial animal tracking data from the Arctic and subarctic exist, most are difficult to discover and access. Here, we present the new Arctic Animal Movement Archive (AAMA), a growing collection...

Ecological “big data” Human activities are rapidly altering the natural world. Nowhere is this more evident, perhaps, than in the Arctic, yet this region remains one of the most remote and difficult to study. Researchers have increasingly relied on animal tracking data in these regions to understand individual species' responses, but if we want to...

The majority of variation in six traits critical to the growth, survival and reproduction of plant species is thought to be organised along just two dimensions, corresponding to strategies of plant size and resource acquisition. However, it is unknown whether global plant trait relationships extend to climatic extremes, and if these interspecific r...

Communities are assembled from species that evolve or colonise a given geographic region, and persist in the face of abiotic conditions and interactions with other species. The evolutionary and colonisation histories of communities are characterised by phylogenetic diversity, while functional diversity is indicative of abiotic and biotic conditions...

Aim Plant functional groups are widely used in community ecology and earth system modelling to describe trait variation within and across plant communities. However, this approach rests on the assumption that functional groups explain a large proportion of trait variation among species. We test whether four commonly used plant functional groups rep...

Climate change is impacting the subsistence livelihoods of many indigenous communities in the Arctic. We describe how structured decision analysis (SDA), informed by traditional ecological knowledge, can be used to understand the mechanisms of how climate change influences subsistence species and their harvest, and to build upon existing adaptive s...

Motivation: The Tundra Trait Team (TTT) database includes field‐based measurements of key traits related to plant form and function at multiple sites across the tundra biome. This dataset can be used to address theoretical questions about plant strategy and trade‐offs, trait–environment relationships and environmental filtering, and trait variation...

Understanding the relationship between environmental factors and vital rates is an important step in predicting a species’ response to environmental change. Species associated with sea ice are of particular concern because sea ice is projected to decrease rapidly in polar environments with continued levels of greenhouse gas emissions. The relations...

The tundra is warming more rapidly than any other biome on Earth, and the potential ramifications are far-reaching because of global feedback effects between vegetation and climate. A better understanding of how environmental factors shape plant structure and function is crucial for predicting the consequences of environmental change for ecosystem...

The above mentioned article was originally scheduled for publication in the special issue on Ecology of Tundra Arthropods with guest editors Toke T. Høye . Lauren E. Culler. Erroneously, the article was published in Polar Biology, Volume 40, Issue 11, November, 2017. The publisher sincerely apologizes to the guest editors and the authors for the in...

Chronic, low intensity herbivory by invertebrates, termed background herbivory, has been understudied in tundra, yet its impacts are likely to increase in a warmer Arctic. The magnitude of these changes is however hard to predict as we know little about the drivers of current levels of invertebrate herbivory in tundra. We assessed the intensity of...

Information on variation in survival among geographically distinct breeding populations can produce valuable insights about the population dynamics of a species. The Yukon-Kuskokwim Delta sub-population of Spectacled Eiders in Alaska decreased precipitously between the 1950s and 1990s. Causes for this decline are unknown but may be attributed to lo...

Pronghorn (Antilocapra americana) in North Dakota have experienced habitat fragmentation due to agricultural practices, roads, and oil development. We analyzed patterns of female pronghorn habitat selection in 2006 and 2014, years with contrasting pronghorn density and oil production in western North Dakota. We quantified resource selection and faw...

Unmanned aircraft systems (UAS) - also called unmanned aerial vehicles (UAVs) or drones - are an emerging tool that may provide a safer, more cost-effective, and quieter alternative to traditional research methods. We review examples where UAS have been used to document wildlife abundance, behavior, and habitat, and illustrate the strengths and wea...

Aim Understanding the forces shaping biodiversity patterns, particularly for groups of organisms with key functional roles, will help predict the responses of ecosystems to environmental changes. Our aim was to evaluate the relative role of different drivers in shaping the diversity patterns of vertebrate herbivores, a group of organisms exerting a...

Warming during the 20th century has changed the arctic landscape, including aspects of the hydrology, vegetation, permafrost, and glaciers, but effects on wildlife have been difficult to detect. The primary aim of this study is to examine the physical and biological processes contributing to the expanded riparian habitat and range of snowshoe hares...

The interacting effects of climate change and habitat fragmentation on wildlife are of global conservation concern. Over the past four decades, pronghorn (Antilocapra americana) populations in North Dakota have been exposed to severe winter weather, drought, predation, harvest, and rapid oil and gas development. Adult pronghorn counts in North Dako...

Shrubs are expanding in Arctic ecosystems, and herbivores may be influencing this expansion by reducing the growth of preferred forage species. We synthesized new and published data to evaluate the relative influence of climate and vertebrate herbivory on different shrub species and groups. Variation in chemistry across shrub species translates to...

In some ecosystems, vertebrate herbivores increase the nutritional quality and biomass of their food source through repeated grazing, thereby manipulating their environment to support higher densities of animals. We tested whether ptarmigan (Lagopus lagopus and L. muta) are capable of regulating the nutritional quality, abundance, and availability...

Shrubs have been expanding in the Arctic over the past century, with important consequences for ecosystem functioning, plant community composition, and wildlife habitat. Herbivores have the capacity to strongly moderate the growth and biomass of shrubs, and therefore need to be considered when attempting to understand and project future changes to...

Shrubs have expanded in Arctic ecosystems over the past century, resulting in significant changes to albedo, ecosystem function, and plant community composition. Willow and rock ptarmigan (Lagopus lagopus, L. muta) and moose (Alces alces) extensively browse Arctic shrubs, and may influence their architecture, growth, and reproduction. Furthermore,...

Rock and willow ptarmigan are abundant herbivores that require shrub habitats in arctic and alpine areas. Shrub expansion is likely to increase winter habitat availability for ptarmigan, which in turn influence shrub architecture and growth through browsing. Despite their ecological role in the Arctic, the distribution and movement patterns of ptar...

Herbivores have the ability to influence the morphology, productivity, and chemistry of their forage plants. In some cases, herbivores increase the quality and quantity of their food source through grazing, thus creating and maintaining “grazing lawns”. In arctic regions of Alaska, moose (Alces alces) and ptarmigan (Lagopus lagopus, L. muta) have t...

Aerial surveys were conducted in the Central Beaufort Sea during late summer and early autumn of 2006-8 to monitor bowhead whale distribution during periods with and without seismic exploration. During some of the 2007-8 surveys large numbers of feeding bowhead whales were seen in an area where feeding has been recorded in the past, but has not bee...

The predictable annual spawning of anadromous salmon (genus Oncorhynchus Suckley, 1861) provides an important marine resource subsidy to terrestrial species throughout the North Pacific. Using isotopic ratios of nitrogen (¹⁵N) and carbon (¹³C), we examine pathways of salmon nutrient uptake by a ground-foraging passerine, the winter wren (Troglodyte...

The annual migration of Pacific salmon (Oncorhynchus spp.) to freshwater streams and lakes provides an important nutrient subsidy to terrestrial systems in North America. We investigated the effects of salmon and other habitat variables on abundance of Winter Wren (Troglodytes troglodytes), Swainson's Thrush (Catharus ustulatus), Varied Thrush (Ixo...

Ecological opportunity can influence niche variation within and among species. Forensic reconstruction of diet has been made possible with the now widespread use of stable isotope analysis, although it has not to date been applied to communities based on carrion resources. Within a salmon-bearing watershed in coastal British Columbia, we reconstruc...

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...