Adults (n -182) were beaten from crowns of bunchgrasses; the introduced South African weeping lovegrass, Eragrostis curuula (n = 104), along highways; sand cordgrass, Spartina bakeri (n = 71), in coastal brackish and freshwater marshes and inland swales, as well as in landscape plantings; and saltmeadow cordgrass, S.
Stemborers associated with smooth cordgrass, Spartina alterniflora (Poaceae), in a nursery habitat.
Regional differences in tidal range, tidal frequency, and winter severity influence the level of disturbance of Spartina habitats (Denno and Grissell 1979, Denno 1983).
On the high marsh, the dead rosettes of short-form Spartina remain in place over winter and then decay during the course of the next season (Squiers and Good 1974).
In addition to differences in winter destruction, tidal inundation also varies markedly between the major Spartina habitats along the Atlantic coast.
The growth dynamics and winter disturbance of Spartina on the Gulf coast contrasts with that along the Atlantic coast (Kurz and Wagner 1957, Turner 1976, Denno and Grissell 1979, Stout 1984).
Although less extreme than along the Atlantic coast, there is evidence for an elevational gradient in the disturbance of Spartina foliosa occupying the Pacific marshes of the San Francisco Bay area.
All plots were sampled once on each date, and each sample consisted of 16 30-s placements of the sampling head over the Spartina vegetation (see Denno et al.
The Pacific coast region was excluded from this analysis because we were unable to obtain a sufficient number of cold-season samples (northern California), and because the distinction between high-marsh and low-marsh habitats is often ambiguous on southern California marshes due to the small patch size of Spartina and its rather homogeneous growth form.
First-instar nymphs hatching from these eggs were used to establish three con-specific density treatments (3, 11, and 40 nymphs/tube cage) on Spartina seedlings, representing the naturally occurring range of densities in the field (Denno and Roderick 1992) (see Denno et al.
marginata population in the low-marsh habitat is associated with the emigration of macropterous adults from tall-form Spartina and their colonization of high-marsh habitats prior to the onset of winter (Denno 1983).
marginata along the entire Atlantic coast [ILLUSTRATION FOR FIGURE 4 OMITTED], when the effects of ice scouring and the subsequent destruction of tall-form Spartina are much more severe to the north (Blum 1968, Squiers and Good 1974, Niering and Warren 1980).
Indeed, populations of this species fail to survive during winter on the smallest of Spartina islets located in the lowest portion of the tidal range (Antolin and Strong 1987).