Longer Growing Seasons Cause Hydrological Regime Shifts in Central European Forests

Sammanfattning

In this study, we present evidence for a hydrological regime shift in upland central European forests. Using a combination of long-term data, detailed field measurements and modelling, we show that there is a prolonged and persistent decline in annual runoff:precipitation ratios that is most likely linked to longer growing seasons. We performed a long term (1950-2018) water balance simulation for a Czech upland forest headwater catchment calibrated against measured streamflow and transpiration from deciduous and coniferous stands. Simulations were corroborated by long-term (1965-2018) borehole measurements and historical drought reports. A regime shift from positive to negative catchment water balances likely occurred in the early part of this century. Since 2007, annual runoff:precipitation ratios have been below the long-term average. Annual average temperatures have increased, but there have been no notable long term trends in precipitation. Since 1980, there has been a pronounced April warming, likely leading to earlier leaf out and higher annual transpiration, making water unavailable for runoff generation and/or soil moisture recharge. Our results suggest a regime shift due to second order effects of climate change where increased transpiration associated with a longer growing season leads to a shift from light to water limitation in central European forests. This will require new approaches to managing forests where water limitation has previously not been a problem.

Nyckelord

forest hydrology; tipping point; water balance modelling

Publicerad i

Forests
2021, Volym: 12, nummer: 12, artikelnummer: 1656
Utgivare: MDPI

SLU författare

• Futter, Martyn

  • Institutionen för vatten och miljö, Sveriges lantbruksuniversitet
    

Globala målen

SDG6 Rent vatten och sanitet för alla
SDG13 Bekämpa klimatförändringarna


UKÄ forskningsämne

Oceanografi, hydrologi, vattenresurser
Klimatforskning
Skogsvetenskap


Publikationens identifierare

DOI: https://doi.org/10.3390/f12121656

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/115719