Delineating seasonal shifts in Reindeer habitat and diet selection by integrating GPS telemetry and stable Isotope analysis

Seasonal changes shape herbivore behaviour by altering forage availability and habitat conditions; however, few studies integrate diet and habitat selection data across temporal scales. This study uses seasonality as a unifying framework to combine fine-scale GPS-based habitat selection data with broader-scale dietary information from stable isotope analysis (δ¹³C, δ¹⁵N) of hairs in semi-domesticated reindeer (Rangifer tarandus tarandus). Thresholds introduced within this framework detect seasonal shifts in habitat and diet selection and classify foraging strategies along a specialist-generalist continuum. Despite individual variability, most individuals exhibited pronounced seasonal changes between spring/early summer (SES) and late summer/autumn (LSA), consistent with generalist foraging strategies. Habitat selection models revealed reduced avoidance of rugged terrain and increased use of mires and bogs from SES to LSA. Concurrently, isotopic enrichment and niche expansion reflected a..., , # Delineating seasonal shifts in reindeer habitat and diet selection by integrating GPS telemetry and stable isotope analysis

Dataset DOI: [10.5061/dryad.5x69p8djm](https://doi.org/10.5061/dryad.5x69p8djm)

## Description of the data and file structure

## Reindeer collaring and hair sampling

Reindeer in Kaldoaivi are rounded up and handled for management purposes twice annually, in mid-to-late winter (February/March) and autumn (October/November), providing opportunities for collaring and sample collection. In February 2019, 15 adult female reindeer were fitted with Ultracom Poro GPS M5 collars (Ultracom Oy, Oulu, Finland) at the Skalluvaara (*Skállovárri*) roundup site (Figure 1c in associated publication). The GPS collars recorded locations at a frequency of four locations per day. Collars were removed during autumn 2019 (N = 13) and spring 2020 (N = 2) roundups, and hair samples were collected from the rump next to the tail and stored in paper bags (Mosbacher et al., 2016). All co...,