The role of Eurasian beaver (Castor fiber) in the storage, emission and deposition of carbon in lakes and rivers of the River Ob flood plain, western Siberia

• Published in: The Science of the total environment 2018-12, Vol.644, p.1371-1379
• Main Authors: Cazzolla Gatti, Roberto, Callaghan, Terry V., Rozhkova-Timina, Inna, Dudko, Anastasia, Lim, Artyom, Vorobyev, Sergey N., Kirpotin, Sergey N., Pokrovsky, Oleg S.
• Format: Article
• Language: English
• Subjects: Animals; Beaver dams; Behavior, Animal; Carbon cycle; Carbon Sequestration; Ecosystem; Lakes; River Ob; Rodentia - physiology; Siberia; Stream ecology; Western Siberia
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2018.07.042

Several studies have reported significant emission of greenhouse gasses (GHG) from beaver dams, suggesting that ponds created by beavers are a net source of CO2 and CH4. However, most evidence come from studies conducted in North America (on Castor canadensis) without a parallel comparison with the Eurasian beaver's (Castor fiber) impacts and a critical consideration of the importance of the carbon deposition in dam sediments. The most abundant population of the Eurasian beaver lives in Russia, notably within the River Ob watershed in Western Siberia which is the second largest floodplain on Earth. Consequently, we assessed the holistic impact of Eurasian beavers on the multiple carbon pools in water and on other related biogeochemical parameters of the Ob's floodplain streams. We compared dammed and flowing streams in a floodplain of the middle course of the river. We found that beavers in western Siberia increase the stream emission of methane by about 15 times by building their dams. This is similar to what has been documented in North America. A new finding from the present study is that Siberian beavers facilitate 1) nutrient recycling by speeding up the nutrient release from particulate organic matter; and 2) carbon sequestration by increasing the amount of dissolved organic carbon. This carbon becomes in part recalcitrant when buried in sediments and is, therefore, removed from the short-term carbon cycle. These new results should be taken into consideration in river management and provide a further reason for the conservation and management of Eurasian Beavers. The processes of carbon-related parameters in ponds created by beaver dams. The dimension of the arrows indicates the strength of the process. Red arrows are both aerobic and anaerobic processes and blue arrows are obligatory anaerobic processes. The strength of the relation between CO2 and DOC is still debated. Mean values ± standard deviation of the significant parameters recorded in the beaver ponds of the river Ob are reported in the figure. [Display omitted] •The impact of carbon emissions from wetlands on climate change has been recently emphasised•Beavers (Castor spp.) influence the biogeochemical cycling of carbon by creating conditions for sediment accumulation in streams and methanogenesis.•We assessed the impact of Eurasian beavers on the whole carbon-related of the Ob river’s effluent floodplain streams in Western Siberia•We compared dammed and free water courses and discussed th