Predicting Long-Term Changes in Riparian Bird Communities in Floodplain Landscapes

Abstract

As anthropogenic impacts on riverine ecosystems expand, both aquatic and terrestrial ecosystems are influenced over large spatiotemporal scales. We predicted how riparian bird communities changed in response to long‐term changes in floodplain landscapes such as woodland expansion (i.e. rapid increases in vegetation cover on gravel bars and the progress of vegetation succession due to a decrease in the frequency and magnitude of flood disturbance). To test the hypothesis that woodland expansion after dam construction reduces the abundance of gravel bar‐nesting birds and increases the abundance of forest‐nesting birds, we estimated historical changes between past and present bird abundances using species distribution models across multiple rivers that were either unregulated or regulated by dams. We created past and present vegetation maps from remote sensing images and used habitat quantities as explanatory variables in the species distribution models. As we hypothesized, the estimated abundance of gravel bar‐nesting birds decreased and that of forest‐nesting birds increased because of woodland expansion in some regulated rivers. This suggests that anthropogenic alterations of riverine conditions (e.g. dam construction) can affect terrestrial ecosystems (e.g. riparian bird communities) through changes in floodplains (e.g. woodland expansion). In addition, our findings highlight the efficacy of combining spatial and temporal analyses when examining long‐term ecological dynamics. Copyright © 2013 John Wiley & Sons, Ltd.

Restoration of the shifting mosaic of floodplain forests under a flow regime altered by a dam

“…Retrospective analysis in the Satsunai River conducted by Yabuhara et al (2015) estimated that large patches (>1.5 ha) of gravel bars have disappeared due to forest encroachment: the number of large gravel bar patches decreased from 13 to 3 over approximately 8 km in river length, and thereby gravel bar-nesting birds decreased by 40%. The young age classes, including unvegetated gravel bars, are nesting and breeding sites for the two plover species.…”

“…Bird species (e.g., Charadrius spp.) that build nests on gravel beds are replaced by forestnesting birds (Yabuhara et al 2015). Additionally, energy flow and aquatic food-web structure may change from autochthonous production to allochthonous input (Riley and Dodds 2012), which may result in changes in macroinvertebrate assemblages (Arscott et al 2003).…”

Riparian Forests and Climate Change: Interactive Zone of Green and Blue Infrastructure

“…Forest expansion causes two major problems for river management. One issue is an increase in channel roughness, which reduces its floodwater transport capacity, and the other issue is a reduction in gravel-bed habitat on which native, rare plant, and animal are dependent species (Nakamura et al 2020;Yabuhara et al 2015).…”

Disentangling the latitudinal and altitudinal shifts in community composition induced by climate change: The case of riparian birds

“…In Europe, most riparian landscapes have been deeply affected by human activities since the mid-nineteenth century, and continue to be altered by agricultural and urban pressures (Tockner et al, 2009). Although the influence of habitat structure on riparian bird communities has been well documented (Roché, 1989;Wenger, 1999), there are few longitudinal studies, and effects are generally assessed over a short time-scale or with predictive models (Yabuhara et al, 2015).…”