EFFECTS OF GRAVEL REMOVAL ON TERRESTRIAL BIOTA 



M. R. Joyce 



INTRODUCTION 



The ecological importance of floodplain and riparian terrestrial habi- 

 tats in temperate regions has been well documented in the ecological litera- 

 ture. These habitats, particularly the riparian zones, have high primary and 

 secondary biological productivity and typically support a diverse and abun- 

 dant flora and fauna. These biotic zones frequently provide temporary and 

 permanent refuge for many of our rare and endangered species. The signifi- 

 cance of these floodplain and riparian habitats has recently been recognized 

 and incorporated into the management plans of several Federal agencies 

 (Johnson and Jones 1977; U.S. Army Corps of Engineers 1979). 



Arctic and subarctic floodplain and riparian habitats are no less 

 significant in their importance and ecological value. The riparian zones 

 develop dense shrub thickets dominated by willows and alder in all four 

 study regions. Overstory forest dominated by white spruce and paper birch 

 also frequently inhabit the riparian zones of the Northern and Southern 

 Interior regions. (Scientific nommenc I a t ure for terrestrial flora and fauna 

 is presented in Appendix A.) High primary productivity in these zones pro- 

 vides optimum feeding, nesting, and cover habitat for a diverse fauna usu- 

 ally dominated by small mammals and passerines. These riparian habitats in 

 interior Alaska frequently support over 100 birds per 40 ha during the 

 nesting season (Spindler and Kessel 1979). Some birds, such as the yellow 

 warbler and northern waterthrush, very seldom nest in habitats other than 

 riparian shrub thickets. These zones also are preferred habitats for tundra 

 voles and singing voles. The more dense riparian shrub thickets provide 

 critical feeding and cover habitats for moose and ptarmigan during winter. 



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