Citizen Science Evidence from the Past Century Shows that Scottish Rivers are Warming
Abstract
Salmonid species are highly sensitive to river water temperature. Although long-term river temperature monitoring is essential for assessing drivers of change in ecological systems, these data are rarely available from statutory monitoring.
We utilized a 105 year citizen science data set of river water temperature from the River Spey, North-East Scotland, gathered during the fishing season (April - October) between 1912 and 2016. As there were gaps in the records we applied generalised additive models to reconstruct long-term daily river temperature in the fishing season from continuous hydrometeorological data from statutory monitoring and process-based models. Air temperature and day length, as surrogate variables for global radiation, and cumulative air temperature, reflecting heat storage in the catchment, are positively related to river temperature. Conversely, precipitation, snow melt, natural runoff, and the ratio of snow melt over total natural runoff reduce river temperature. Long-term warming trends of river temperature, namely an increase of 0.2 K per decade after 1962, have been mostly related to increasing global radiation as reflected by an air temperature increase of the same magnitude. Indirect impacts of rising air temperatures include less snow accumulation and snow melt as well as an earlier snow melt. The snow free period starts around 2 days earlier per decade throughout the study period and 7 days earlier per decade after 1965. Consequently, the contribution of snow melt and its cooling properties to river temperature in spring are declining. Citizen science delivered a data set that filled a vital knowledge gap in the long-term historical assessment of river temperatures. These can provide a robust basis for future assessments of global change and can help inform decision-makers about the desirability of enhancing the resilience of rivers and aquatic ecology to warming.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H13C..02P
- Keywords:
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- 0439 Ecosystems;
- structure and dynamics;
- BIOGEOSCIENCESDE: 1807 Climate impacts;
- HYDROLOGYDE: 1813 Eco-hydrology;
- HYDROLOGYDE: 1899 General or miscellaneous;
- HYDROLOGY