Sammanfattning

There are concerns that environmental changes, such as climate variability and forest harvesting, are altering stream thermal regimes and impacting aquatic ecosystems. Previous studies have suggested that the abundant headwater lakes found in northern landscapes may moderate downstream temperature response to forest harvesting. We investigated this hypothesis using a virtual experimental approach based on detailed field measurements made at boreal catchments in northern Sweden coupled with a process-based stream temperature model. We simulated streamside harvesting for stream reaches with and without a headwater lake. Mean daily summer stream temperature response to harvesting was generally between 0.5 and 1.5 degrees C higher for the stream without a lake than for the stream with a lake. However, during rain events the stream with the lake showed a greater stream temperature response than the stream without a lake. Headwater lakes typically store and delay runoff from rain events, augment baseflow, and have elevated outflow temperatures. These differences in upstream boundary conditions, in terms of flow and water temperature, were the key drivers for the contrasting harvest responses between streams with and without headwater lakes. These findings were generally consistent across different harvesting scenarios; however, uncertainty in the hyporheic term and post-harvest microclimate conditions influenced the simulated magnitude of post-harvest stream temperature response. Our study highlights the utility of virtual experiments for gaining insight on systems understanding but caution is needed when using models for predictions outside the conditions for which models are calibrated.

Nyckelord

energy budget; forest harvesting; lakes; stream networks; stream temperature; virtual experiments

Publicerad i

Hydrological Processes
2022, Volym: 36, nummer: 6, artikelnummer: e14593
Utgivare: WILEY

SLU författare

• Laudon, Hjalmar

  • Institutionen för skogens ekologi och skötsel, Sveriges lantbruksuniversitet
    

Associerade SLU-program

SLU Skogsskadecentrum


Globala målen

SDG15 Skydda, återställa och främja ett hållbart nyttjande av landbaserade ekosystem, hållbart bruka skogar, bekämpa ökenspridning, hejda och vrida tillbaka markförstöringen samt hejda förlusten av biologisk mångfald
SDG13 Vidta omedelbara åtgärder för att bekämpa klimatförändringarna och dess konsekvenser


UKÄ forskningsämne

Miljövetenskap
Oceanografi, hydrologi, vattenresurser


Publikationens identifierare

DOI: https://doi.org/10.1002/hyp.14593

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/117402