Spatial and Temporal Variability of Channel Retention in a Lowland Temperate Forest Stream Settled by European Beaver (Castor fiber)

Abstract

Beaver ponds remain a challenge for forest management in those countries where expansion of beaver (Castor fiber) is observed. Despite undoubted economic losses generated in forests by beaver, their influence on hydrology of forest streams especially in terms of increasing channel retention (amount of water stored in the river channel), is considered a positive aspect of their activity. In our study, we compared water storage capacities of a lowland forest stream settled by beaver in order to unravel the possible temporal variability of beaver's influence on channel retention. We compared distribution, total damming height, volumes and areas of beaver ponds in the valley of Krzemianka (Northeast Poland) in the years 2006 (when a high construction activity of beaver was observed) and in 2013 (when the activity of beaver decreased significantly). The study revealed a significant decrease of channel retention of beaver ponds from over 15,000 m 3 in 2006 to 7000 m 3 in 2013. The total damming height of the cascade of beaver ponds decreased from 6.6 to 5.6 m. Abandoned beaver ponds that transferred into wetlands, where lost channel retention was replaced by soil and groundwater retention, were more constant over time and less vulnerable to the external disturbance means of water storage than channel retention. We concluded that abandoned beaver ponds played an active role in increasing channel retention of the river analyzed for approximately 5 years. We also concluded that if the construction activity of beaver was used as a tool (ecosystem service) in increasing channel retention of the river valley, the permanent presence of beaver in the riparian zone of forest streams should have been assured. OPEN ACCESSForests 2014, 5 2277

Activity of beavers as an ecological factor that affects the benthos of small rivers - a case study in the Żylica River (Poland)

“…The activity of beavers contributes to an increase in the surface and groundwater retention, which has an influence on stream morphometry (Naiman et al 1986 ; Smith et al 1989 ; Westbrook et al 2006 ; Grygoruk and Nowak 2014 ). The proper functioning of a dam also reduces the severity of flooding events.…”

Ecosystem services provided by beavers Castor spp.

“…Increases in groundwater storage capacity, water table level, and aquifer recharge have been observed in several studies (e.g. Westbrook et al 2006, Grygoruk & Nowak 2014). Grygoruk and Nowak (2014) estimated the annual water storage value provided by beavers in Krzemianka Valley, Poland, to approximately equal € 4000.…”

“…Westbrook et al 2006, Grygoruk & Nowak 2014). Grygoruk and Nowak (2014) estimated the annual water storage value provided by beavers in Krzemianka Valley, Poland, to approximately equal € 4000. In our meta‐regression results, the water supply service totalled 20 million USD(2017) per year (dam‐builders only; Table 5; variable Supply).…”

Local knowledge about a newly reintroduced, rapidly spreading species (Eurasian beaver) and perception of its impact on ecosystem services

“…As for erosion control, the literature clearly indicates positive impacts [64,65,61], while locals mostly perceived negative ones. That may be because they were more conspicuous than the mostly indirect positive impacts.…”