Sandra Lai

University of Oxford | OX · Biology

Understanding how species adjust to seasonality is fundamental in ecology, especially with rapidly increasing global air temperatures. Bioacoustic monitoring offers promise for tracking shifts in seasonal timing of vocal species, as recent automated sound recorders enable large-scale and long-term data collection. Yet, analyzing vast datasets neces...

The use of remote sensing for developing land cover maps in the Arctic has grown considerably in the last two decades, especially for monitoring the effects of climate change. The main challenge is to link information extracted from satellite imagery to ground covers due to the fine-scale spatial heterogeneity of Arctic ecosystems. There is current...

Boldness is an important trait in wild populations, and among-individual differences can link to individual fitness. The strength and direction of relationships between behavioral and life-history traits may however vary according to environmental conditions, where fluctuating selection acting on behavioral traits contributes to the maintenance of...

Arctic rabies is an ongoing threat to human populations and domestic animals inpolar regions, where Arctic foxes (Vulpes lagopus) are the main reservoir hosts. Human-driven changes in resource availability are shifting the distribution of Arctic foxes and these changes may affect the risk of rabies transmission and spread. Our understanding of the...

Long-distance dispersal plays a key role in species distribution and persistence. However, its movement metrics and ecological implications may differ whether it is undertaken by juveniles (natal dispersal) or adults (breeding dispersal). We investigated the influence of life stage on long-distance dispersal in the Arctic fox, an important tundra p...

Polar deserts, characterized by barren grounds and continuous permafrost, are the most extreme environments in the Northern Hemisphere. Due to their remoteness and thus considerable logistical challenges, very few study sites are located in this biome. However, despite the scarcity of their biodiversity, polar desert landscapes are the most represe...

The black-footed cat (Felis nigripes) is the smallest felid species in Africa and is endemic to the arid regions of southern Africa. It is currently listed as “Vulnerable” in the International Union for the Conservation of Nature (IUCN) red list of threatened species, with a population decline suspected over the general range. Since 2005, the B...

Animal migration contributes largely to the seasonal dynamics of High Arctic ecosystems, linking distant habitats and impacting ecosystem structure and function. In polar deserts, Arctic hares are abundant herbivores and important components of food webs. Their annual migrations have long been suspected, but never confirmed. We tracked 25 individua...

Rapid range expansion of boreal forest predators onto the tundra may disrupt local ecological processes, notably through competition with ecologically similar species. Red foxes (Vulpes vulpes) have expanded their range northwards throughout the Canadian Arctic, inducing competition with endemic Arctic foxes (V. lagopus). We studied competition bet...

Caribou and reindeer migrations are the tip of the iceberg when one considers migration among the 70 species of Arctic terrestrial mammals. About 26% of species indeed have migratory individuals, while 33% are non-migratory and 41% are data deficient. Such figures demonstrate the need to both better document and better understand seasonal movements...

Long-distance movements undertaken by animals are among the most fascinating biological phenomena on Earth. They include dispersal to reach new breeding sites, predictable migrations, and various forms of resource-based nomadism. About 12% of vertebrate species undertake large-scale migrations, but because the costs of terrestrial locomotion are hi...

The startling warming of the Arctic is driving important environmental changes, but vegetation responses have been spatially heterogeneous and difficult to predict. In this context, establishing new ecological baselines and initiating monitoring schemes are essential. We conducted systematic plot-based surveys in the polar desert surrounding Alert...

Long-term monitoring is critical to guide conservation strategies and assess the impacts of climatic changes and anthropogenic activities. In High Arctic ecosystems, information on distribution and population trends of plants is dramatically lacking. During two field expeditions in 2018 and 2019, we conducted a systematic floristic survey together...

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...

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...

As top or mesopredators, carnivores play a key role in food webs. Their survival and reproduction are usually thought to be influenced by prey availability. However, simultaneous monitoring of prey and predators is difficult, making it challenging to evaluate the impacts of prey on carnivores’ demography. Using 13 years of field data on arctic foxe...

Managing species at risk and their critical habitats is challenging in situations where information is scarce, such as is often the case in the Arctic. Remote sensing provides a lot of information simply by the acquisition of images of the surface of the Earth. Recently, the increased efficiency of airborne and satellite sensors has facilitated the...

Camera traps now represent a reliable, efficient and cost-effective technique to monitor wildlife and collect biological data in the field. However, efficiently extracting information from the massive amount of images generated is often extremely time-consuming and may now represent the most rate-limiting step in camera trap studies. To help overco...

Bien que la toundra arctique demeure majoritairement non perturbée par les activités humaines directes, offrant des opportunités uniques de préserver son intégrité écologique, l’intensification des perturbations humaines est évidente et générera le besoin de développer des Plans de Gestion de la Biodiversité (PGB). De tels plans ont été proposés da...

We present several methods that can be used to monitor Arctic and red foxes in the Arctic tundra, with a focus on breeding activities. We highlight the pros and cons of each method.

Objective The arctic fox (Vulpes lagopus) is a circumpolar species inhabiting all accessible Arctic tundra habitats. The species forms a panmictic population over areas connected by sea ice, but recently, kin clustering and population differentiation were detected even in regions where sea ice was present. The purpose of this study was to examine t...

The sociality of the Arctic fox has been extensively studied during the breeding season, so that its summer territorial and generally monogamous social systems are now well described. A key knowledge gap remains, however, during the winter season, when logistic challenges preclude detailed observation of individuals. We have studied the socio-spati...

Animal movement is a fundamental process shaping ecosystems at multiple levels, from the fate of individuals to global patterns of biodiversity. The spatio-temporal dynamic of food resources is a major driver of animal movement and generates patterns ranging from range residency to migration and nomadism. Arctic tundra predators face a strongly flu...

Identifying correctly trophic interactions is important for understanding population dynamics and ecosystem functioning. However, some predator–prey relationships may still remain undetected, due to the difficulty of observing rare predation events. We report the first observation of predation of arctic fox (Vulpes lagopus) pups by common ravens (C...

Background The scale at which animals perceive their environment is a strong fitness determinant, yet few empirical estimates of animal detection ranges exist, especially in mammalian predators. Using daily Argos satellite tracking of 26 adult arctic foxes (Vulpes lagopus) during a single winter in the High Canadian Arctic, we investigated the dete...

Arctic wildlife is often presented as being highly at risk in the face of current climate warming. We use the long-term (up to 24 years) monitoring records available on Bylot Island in the Canadian Arctic to examine temporal trends in population attributes of several terrestrial vertebrates and in primary production. Despite a warming trend (e.g. c...

Swarming is a type of social motility allowing the migration of highly differentiated bacterial cells. Swarming shares many similarities with biofilm communities, which are notable for their high resistance to antimicrobial agents. We investigate here if the swarming behaviour could also be associated with a widespread antimicrobial resistant pheno...