Climate Change Impacts on Arctic Herbivore Dynamics

Arctic herbivores such as reindeer and muskoxen occupy a pivotal role in tundra ecosystems, linking vegetation dynamics to predator populations and supporting cultural livelihoods. Rapid warming in polar regions is altering seasonal cycles, with warmer summers advancing plant growth and extending foraging periods, while milder winters can bring rain-on-snow events that form ground ice and restrict access to forage. These opposing seasonal effects influence body condition, survival and reproductive success, producing complex population trajectories. Extreme weather, including sudden icing or storm surges, can precipitate mass mortality or trigger resilience mechanisms through density-dependent feedbacks and shifts in age structure. Simultaneously, changes in vegetation quality, driven by altered nutrient availability and phenology, affect foraging choices and calf recruitment. Understanding these interwoven processes is essential for forecasting ecosystem responses, guiding conservation strategies and sustaining indigenous practices that depend on stable herbivore populations.

Research from Nature Portfolio

Empirically parameterised models of High-Arctic wild reindeer have revealed that more frequent rain-on-snow events can paradoxically stabilise population dynamics. By selectively suppressing vital rates in older age classes at high density, these events induce population crashes that reset age structure towards more resilient cohorts, thereby reducing extinction risk under stochastic climate perturbations. Another line of investigation into cold-adapted mammals demonstrates that acute rain-on-snow events and unusual winter tidal surges severely impair skeletal growth in juvenile muskoxen and, in extreme cases, entomb entire herds. Such findings expose previously unknown pathways by which rare or intensifying weather anomalies constrain life history and long-term viability in Arctic ungulates.

Climate Change Impacts on Arctic Herbivore Dynamics publication trend

The graph below shows the total number of articles in climate change impacts on arctic herbivore dynamics across all publications each year (not limited to Nature Index journals).

Technical terms

Rain-on-snow event: A weather phenomenon in which rain falls on existing snow cover and subsequently freezes, forming an impermeable ice layer that restricts herbivore access to ground forage.

Density dependence: A regulatory process by which population vital rates (survival, reproduction) change in response to population density, often leading to feedbacks that stabilise or destabilise population size.

Ground icing: The formation of ice on plant surfaces and soil caused by freezing conditions, which can entomb herbivores or block access to food.

Phenology: The study of the timing of seasonal biological events, such as plant green-up and animal reproduction, and their synchrony with environmental factors.

Trophic mismatch: A temporal misalignment between the peak abundance of a food resource (for example, young plant shoots) and the critical life-history stages of a consumer (for example, breeding or lactation).

References

1. More frequent extreme climate events stabilize reindeer population dynamics. Nature Communications (2019).
2. Climate Degradation and Extreme Icing Events Constrain Life in Cold-Adapted Mammals. Scientific Reports (2018).
3. Geochemical landscapes as drivers of wildlife reproductive success: Insights from a high-Arctic ecosystem. The Science of The Total Environment (2023).
4. Contrasting effects of summer and winter warming on body mass explain population dynamics in a food‐limited Arctic herbivore. Global Change Biology (2016).
5. The neglected season: Warmer autumns counteract harsher winters and promote population growth in Arctic reindeer. Global Change Biology (2020).