TY  - JOUR
A1  - Kong, Xiangzhen
A1  - Ghaffar, Salman
A1  - Determann, Maria
A1  - Friese, Kurt
A1  - Jomaa, Seifeddine
A1  - Mi, Chenxi
A1  - Shatwell, Tom
A1  - Rinke, Karsten
A1  - Rode, Michael
T1  - Reservoir water quality deterioration due to deforestation emphasizes the indirect effects of global change
JF  - Water research : a journal of the International Association on Water Quality (IAWQ)
N2  - Deforestation is currently a widespread phenomenon and a growing environmental concern in the era of rapid climate change. 
In temperate regions, it is challenging to quantify the impacts of deforestation on the catchment dynamics and downstream aquatic ecosystems such as reservoirs and disentangle these from direct climate change impacts, let alone project future changes to inform management. 
Here, we tackled this issue by investigating a unique catchment-reservoir system with two reservoirs in distinct trophic states (meso- and eutrophic), both of which drain into the largest drinking water reservoir in Germany. 
Due to the prolonged droughts in 2015-2018, the catchment of the mesotrophic reservoir lost an unprecedented area of forest (exponential increase since 2015 and ca. 17.1% loss in 2020 alone). 
We coupled catchment nutrient exports (HYPE) and reservoir ecosystem dynamics (GOTM-WET) models using a process-based modeling approach. The coupled model was validated with datasets spanning periods of rapid deforestation, which makes our future projections highly robust. 
Results show that in a short-term time scale (by 2035), increasing nutrient flux from the catchment due to vast deforestation (80% loss) can turn the mesotrophic reservoir into a eutrophic state as its counterpart. 
Our results emphasize the more prominent impacts of deforestation than the direct impact of climate warming in impairment of water quality and ecological services to downstream aquatic ecosystems. Therefore, we propose to evaluate the impact of climate change on temperate reservoirs by incorporating a time scale-dependent context, highlighting the indirect impact of deforestation in the short-term scale. In the long-term scale (e.g. to 2100), a guiding hypothesis for future research may be that indirect effects (e.g., as mediated by catchment dynamics) are as important as the direct effects of climate warming on aquatic ecosystems.
KW  - deforestation
KW  - climate change
KW  - temperate regions
KW  - reservoir
KW  - eutrophication
KW  - process-based modeling
Y1  - 2022
U6  - https://doi.org/10.1016/j.watres.2022.118721
SN  - 0043-1354
SN  - 1879-2448
VL  - 221
PB  - Elsevier Science
CY  - Amsterdam [u.a.]
ER  -