Hydrology influences breeding time in the white-throated dipper

Area of Science:

• Ecology
• Climate Change Biology
• Ornithology

Background:

• Global change significantly impacts bird breeding timing, a critical factor for reproductive success.
• Previous studies often overlooked local environmental conditions, focusing on large-scale climate data.
• Riverine ecosystems face altered flow regimes due to climate change and hydropower demands, affecting breeding windows for associated birds.

Purpose of the Study:

• To investigate how territory-level environmental conditions influence breeding timing in the white-throated dipper (Cinclus cinclus).
• To analyze the relationship between hydrological parameters and breeding phenology in a long-term study.

Main Methods:

• Utilized a long-term dataset of white-throated dipper breeding phenology (1978-2015).
• Correlated daily river discharge and hydrological data with breeding timing at the territory level.
• Examined environmental factors including winter river discharge, groundwater levels, snow cover, and altitude.

Main Results:

• Earlier breeding was observed with high winter river discharge, high groundwater levels, and low snow cover.
• Lower altitudes showed earlier breeding, though this effect diminished over time.
• Territory river discharge during winter had the most significant impact on advancing breeding time.

Conclusions:

• Earlier bird breeding is a discernible response to ongoing climate change.
• Territory-specific environmental measurements offer crucial insights into organism-environment interactions.