Plant Succession on Gopher Mounds in Western Cascade Meadows: Consequences for Species Diversity and Heterogeneity

Abstract

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.3

Global meta‐analysis of soil‐disturbing vertebrates reveals strong effects on ecosystem patterns and processes

“…Soil disturbance initiates substantial shifts in biotic community composition so that accreting and eroding surfaces often support a community that is distinct from the surrounding matrix (Aplet, Anderson, & Stone, ; Gómez‐Garcia, Borghi, & Giannoni, ; Jones, Halpern, & Niederer, ). Shifts may occur stochastically or because disturbances favour organisms with particular resource requirements or traits relating to colonization and disturbance tolerance (Eldridge & James, ).…”

Vegetation Recovery in Slash‐Pile Scars Following Conifer Removal in a Grassland‐Restoration Experiment

“…Gophers are prominent in many North American grasslands, disturbing as much as 30% of the ground surface in a given year (Huntly & Reichman ). Studies of open‐meadow communities at Bunchgrass Ridge suggest that frequent, small‐scale disturbances create a shifting mosaic of vegetation states—reducing local dominance of graminoids and enhancing the richness and heterogeneity of species at larger spatial scales (Jones et al ; Case et al ). Rapid immigration of gophers into the restoration plots has resulted in substantial mixing of fire‐affected soils (Halpern et al ).…”

Interactions between soil biota and the effects on geomorphological features

“…The active spores may then form symbiotic relationships with oaks in areas that are not otherwise included in the mycorrhizal net, promoting spread of these oaks (ibid.). In montane meadow soils, western pocket gophers (Thomomys mazama) decrease graminoid (grass species) dominance and increase dominance of forbs (broadleaf plants), which does not increase overall biomass or diversity but does promote patchiness of plant species within the meadow (Jones et al, 2008). In contrast, the plains pocket gopher (G. bursarius) had no effect on the plant community in an established tallgrass prairie in Kansas (Rogers et al, 2001).…”