Disputation: Samantha Paige Huset Dwinnell

Dwinnell has been following the PhD programme at the Faculty of Environmental Sciences and Natural Resource Management, NMBU, and is defending her doctoral thesis at UNIS 29 August 2025:

«Herbivore responses to climate-driven food supply in a warming Arctic: nutritional benefits and adaptive foraging strategies of Svalbard reindeer»

The doctoral thesis is available for public review. For those of you who want access to the thesis in pdf-form, please send an email to Brage Monsen – brage.monsen@nmbu.no.  

Public summary:

Large herbivores in Arctic regions, such as Svalbard reindeer (Rangifer tarandus ssp. platyrhynchus), have adapted to seasonal food supply using energy stores (e.g., fat) gained during summer periods of abundance to finance survival and reproduction through long winter periods of food scarcity. Climate change is altering plant growth and timing of availability, creating a more variable and less predictable food supply for reindeer relying on it. We explored the connections linking weather- and climate-driven shifts in food availability to the behavioral and fitness-related responses of Svalbard reindeer in the fastest-warming region on Earth. Using a combination of long-term, monitoring of individual reindeer behavior and body condition, on-the-ground measurements of plant growth and ground ice, and remotely sensed data on broader environmental conditions,  we began to uncover the mechanisms linking climate to a 3.5-fold increase in Svalbard reindeer over the past 26 years. This body of work demonstrates that high-Arctic reindeer have benefited from positive plant responses to warming and exhibit flexible foraging, likely enabling adaptive responses to rapid environmental changes. This resilience may persist as long as warming remains within their adaptive thresholds, but continued Arctic warming could challenge these benefits, underscoring the need for ongoing research on large herbivore responses to climate change.

Opponent ex auditorio:

Questions ex auditorio can be submitted to Disputation Chair prof. Jan Vermaat