Document Type

Article

Publication Date

2008

Comments

Initially published in American Midland Naturalist, Vol.159(2) April 2008, pp.275-286

The American Midland Naturalist © 2008 The University of Notre Dame

https://doi.org/10.1674/0003-0031(2008)159[275:PSOGMI]2.0.CO;2

Abstract

Pocket gophers have the potential to alter the dynamics of grasslands by creating mounds that bury existing vegetation and locally reset succession. Gopher mounds may provide safe sites for less competitive species, potentially increasing both species diversity and vegetation heterogeneity (spatial variation in species composition). We compared species composition, diversity and heterogeneity among gopher mounds of different ages in three montane meadows in the Cascade Range of Oregon. Cover of graminoids and forbs increased with mound age, as did species richness. Contrary to many studies, we found no evidence that mounds provided safe sites for early successional species, despite their abundance in the soil seed bank, or that diversity peaked on intermediate-aged mounds. However, cover of forbs relative to that of graminoids was greater on mounds than in the adjacent meadow. Variation in species composition was also greater within and among mounds than in adjacent patches of undisturbed vegetation, suggesting that these small-scale disturbances increase heterogeneity within meadows.

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The views expressed in this paper are solely those of the author.