# Assessment of the potential shifts in the phenological development of representative spring plant species in Slovenia until the end of the 21st century using a model-based approach

## TL;DR

This study predicts that spring plant species in Slovenia will bloom earlier by the end of the 21st century, with higher elevations experiencing more significant changes due to rising temperatures.

## Contribution

The study introduces a climate-driven phenological model to predict elevation-dependent shifts in spring phenology in Slovenia.

## Key findings

- Spring phenophases in Slovenia are projected to occur earlier by the end of the 21st century.
- Higher elevations will experience more pronounced advancements in spring phenology.
- Model predictions align with observed records and show elevation-dependent variation.

## Abstract

To assess the changes in the spring phenology in the future with particular emphasis on the elevation dependence of phenophase onset, a climate-driven phenological model was developed based on the spring indices methodology. Our study investigates both current and projected changes in the timing of flowering onset for common hazel (Corylus avellana), dandelion (Taraxacum officinale), and common lilac (Syringa vulgaris). We compiled comprehensive climate data and phenological records from 46 phenological stations of the National Phenological Network of the Slovenian Environment Agency for the period 1971–2020. In addition, we used climate projection data for the 21st century under two climate scenarios to evaluate potential future shifts in the onset of the selected phenophases. Specifically, we examined whether the agreement between model predictions and observed records varies with elevation during the reference period (1981–2010) and whether this relationship changes across three future climate periods: 2011–2040, 2041–2070, and 2071–2100. Model results indicate that spring phenophases are expected to occur earlier in Slovenia by the end of the 21st century, consistent with the projected increase in air temperatures. Moreover, the advancement in spring phenology will be more pronounced at higher elevations.