Naturalization of Russian-Olive: Implications to Rocky Mountain Wildlife

Knopf, Fritz; Olson, Thomas

Naturalization and spreading of exotic woody vegetation in riparian zones have received much attention in recent years. This attention has been directed primarily at salt-cedar tamarisk (Tamarix pentandra) in south-western states (e.g. Robinson 1965, Horton 1977). Tamarisk along the lower Colorado River does not compare favorably with native woody vegetation as avian habitats (Anderson et al. 1977) and, without control, will completely displace native riparian vegetation with time (Horton 1977). Russian-olive (Elaeagnus angustifolia) is a native of Europe and western Asia introduces into North American prior to 1900. The spreading, sometimes shrub-like, tree tolerates a wide range of soil and moisture conditions, adapting to local conditions throughout the western United Sates from Minnesota to Kansas to the Pacific Ocean (Borell 1976). The history of Russian-olive in western states was summarized by Christensen (1963). Briefly, the species was being planted extensively in residential areas by 1900. Russian-olives were first reported escaping cultivation in 1924 in Utah, 1925 in Nevada, 1942 in Arizona and California, 1952 in Idaho, 1954 in Colorado, and 1960 in New Mexico and Texas. Russian-olive has been promoted, especially by soil conservationists, as an excellent planting for windbreaks, erosion control, and wildlife enhancement (Van Dersal 1939, Wilson 1944, Billings 1945, Graham 1949, Borell 1976). Over 50 species of birds and mammals use Russian-olive as a source of food or cover (Borell 1976). Recently, we noticed that extensive, virtually monotypic stands of Russian-olive have invaded riparian zones of some western (Green, Missouri, Snake) river systems. These riparian zones provide critical, limited habitats for many vertebrate species in the West (Johnson and Jones 1977). This paper (1) alerts natural resource conservation personnel to naturalization of Russian-olive in the West, (2) reports on the avian and mammalian associations of monotypic stands of Russian-olive in 3 western states, (3) discussed similarities of those associations to vertebrate communities occurring in nearby native riparian and upslope vegetation types using the analytical approach discussed by Samson and Knopf (1982), and (4) speculates on implications of the continued naturalization of Russian-olive to Rocky Mountain avian and mammalian communities. (Abstract by Knopf and Olson as printed in Wildlife Society Bulletin).

Naturalization of Russian-Olive: Implications to Rocky Mountain Wildlife

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