Open Collections

Moore, Emily

University of British Columbia

Negative impacts of climate change and watershed disturbance are becoming increasingly important for freshwater ecosystems in the Pacific Northwest. Increased air temperatures and changes to precipitation regimes alter stream flow and temperature, especially in snow- dominated watersheds. Changes in these habitat variables can impact the success of critical salmonid life stages, such as spawning, leading to population decline. Kokanee fisheries in the Okanagan Valley have immense economic and cultural value, however their continued success is threatened by a changing climate. The questions I aimed to address with my research were: (1) which hydroclimatic variables were the most influential in determining the timing of kokanee spawning in Peachland and Trepanier Creeks over the last 30 years? And (2) how will a changing climate alter spawn timing in the future? Linear models were created to predict both spawning start time and duration in both creeks. Results showed that kokanee spawning in both creeks had advanced an average of 6 days in both creeks over the past 30 years. The timing of spawning was most strongly predicted by variables related to air temperature such as accumulated thermal units of air temperature, climate moisture deficit in the summer, and average autumn temperature, where higher air temperatures were correlated with earlier spawning. Flow appeared to be more important for determining spawn timing in unregulated Trepanier Creek. This difference likely arose due to the presence of a dam in Peachland Creek watershed which provided regulated flows throughout the spawning period. Spawning duration was best predicted by temperature variables and spawning start time, with an earlier spawning start contributing to a longer spawning duration. Climate change models predict alterations to relevant hydroclimatic variables that will lead to advanced spawning in both creeks. Spawning duration was also predicted to increase under climate change, however the consideration and inclusion of biological controls on spawning duration in the model would improve prediction capability.

Text

2024-02-16

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/87456

Earth and Environmental Sciences

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/