Land cover effects on hydrologic services under a precipitation gradient

Abstract

Abstract. Climate change impacts on the hydrological cycle are altering the quantity, quality, and temporal distribution of riverine discharge, necessitating a more rigorous consideration of changes in land cover and land use. This study establishes relationships between different land cover combinations (e.g., percentages of forest -both native and exotic -and pastureland) 15 and hydrological services, using hydrological indices estimated at annual and seasonal time scales in an area with a steep precipitation gradient (900-2600 mm y -1 ). Using discharge data from 20 catchments in the Bay of Biscay, a climate transition zone, the study applied multiple regression models to better understand how the interaction between precipitation and land cover combinations influence hydrological services. Findings showed the relationship between land cover combinations and hydrological services is highly dependent on the amount of precipitation, even in a climatically homogeneous and relatively 20 small area. In general, in the Bay of Biscay area, the greater presence of any type of forests is associated with lower annual water resources, especially with greater percentages of exotic plantations and high annual precipitation. Where precipitation is low, forests show more potential to reduce annual and winter high flows than pasturelands, but this potential decreases as annual or seasonal precipitation increases. As annual precipitation increases, low flows increase as the percentage of exotic plantations decreases and pasturelands increase. Results obtained in this study improve understanding of the multiple effects 25 of land cover on hydrological services, and illustrate the relevance of land planning to the management of water resources, especially under a climate change scenario.

2030 Agendako helburuetatik lurra-ura hartzera

“…Gurera etorrita, eta adibide modura, Gipuzkoako hainbat ibai-arrotan egin ditugun ikerketen emaitzek erakusten dute edozein baso mota egoteak murriztu egiten duela urteko batezbesteko uremaria (ur-hornidura zerbitzua), murrizketa hori handiagoa izanik urteko prezipitazioa handitu ahala, eta eragin hori nabariagoa dela landaketa exotikoak dauden ibai-arroetan [22]. Gainera, beste azterketa batzuen antzera [23][24], azterlan horrek erakusten du basoek ur-goraldiak arintzeko duten potentziala txikia dela (batez ere uholde-mehatxua dagoenean), ohiko premisek diotenaren kontrara; hala ere, lurestaldurak izan dezakeen eragina aldatu egiten da lekuan-lekuko eta urtean-urteko aldagai klimatikoekin.…”