| dc.description.abstract | Although natural flooding is an important part of the riparian ecology, climate change is expected to affect the hydrological cycle and alter flow patterns including the timing and frequency of flood. Similar changes can occur when rivers are regulated for hydropower use. The negative impacts floods have on many terrestrial mammals during the reproduction period is previously studied, but little is known about the effect flooding has on the offspring of semi-aquatic mammals, such as the keystone species beaver (Castor spp.). The beaver has very specific requirements concerning lodge placement, making it especially susceptible to changes in water level and flow variability. Using beaver demography data spanning two decades, from three rivers differently affected by hydropower regulation, I investigate the effects of flood peaks on Eurasian beaver (C. fiber) kit survival. I investigated whether flood peaks had an impact during the time the kits are confined to the lodge in spring, at the time of emergence in the summer and later when the kits swim freely in autumn and winter. I also investigated whether beaver lodges will have an increased risk of submersion in the future. I found that flood peaks during the time of emergence from the lodge in summer had an impact on beaver kit survival, but not during the time kits are confined to the lodge in spring or in autumn and winter. Additionally, I found that the beaver population may be affected by more severe floods in the future through lodge submersions. Here I demonstrate that flood peak timing may be more important than flood magnitude on offspring survival in a semi-aquatic mammal. | |
