3.2.2 Animals of the Wetland-Upland 

 Transition 



The animals of the transition community 

 include snakes, lizards, rodents, and birds. 

 The herpetofauna was studied by Robert 

 Espinoza for the tidal restoration plan (in 

 Entrix et al. 1991). Most of the species found 

 were located by observation, rather than 

 trapping. California kingsnakes (Lampro- 

 peltis getulus californiae) and San Diego 

 gopher snakes (Pituophis melanoleucus 

 annectens) are common species that were seen 

 in transition habitats. The side-blotched 

 lizard (Uta stansburiana) was abundant on 

 dry ground, especially in sandy, open areas. 



Ernest Taylor and John Tiszler trapped 

 small mammals monthly between November 

 1988 and May 1989 as part of the resource 

 inventory for tidal restoration planning 

 (Entrix et al. 1991). Two species were 

 captured in the transition habitat (5 sampling 

 plots with 10 trap stations per 0.04-ha 

 plot), with 92% of the captures being 

 western harvest mouse (Reithrodontomys 

 megalotis) and 8% deer mouse (Peromyscus 

 maniculatus). The latter species was trapped 

 only in May in the transition habitat. The 

 combined density of these two species ranged 

 from (in December) to 15 (April and May) 

 per hectare. 



Other mammals were trapped or observed 

 in the upland habitats around Goat Canyon; 

 species included three carnivores, the coyote 

 (Canis latrans), striped skunk (Mephitis 

 mephitis) and the long-tailed weasel (Mustela 

 frenata). The California jackrabbit (Lepus 

 californicus), desert cottontail (Sylvilagus 

 audoboni), opossum (Didelphis virginianis), 

 and California ground squirrel (Spermophilus 

 beechyi) were also observed. It is likely that 

 these larger, highly mobile animals visit the 

 wetland from time to time. Traps in the 

 upland captured additional small mammals: 

 agile kangaroo rat (Dipodomys agilis), San 

 Diego pocket mouse (Perognathus fallax), 

 cactus mouse (Peromyscus eremicus), brush 

 mouse (Peromyscus boyli), and dusky footed 

 woodrat (Neotoma fuscipes). 



The small mammal species are no doubt 

 prey for various birds. Of special interest in 



the transition habitat are the short-eared owl 

 (Asio flammeus), northern harrier (Circus 

 cyaneus), and black-shouldered kite (Elanus 

 caeruleus). 



3.3 INTERTIDAL SALT MARSH 



While the salt marsh appears to be a 

 plant-dominated community, it provides 

 habitat for a wide variety of animals, 

 including resident and migratory species. 

 Large shorebirds feed and rest in the marsh, 

 while smaller shorebirds use the marsh as a 

 nocturnal roosting site. Insects and benthic 

 invertebrates are likewise abundant in the 

 intertidal marsh. The plants structure the 

 community and support a complex food web. 



Espinoza (in Entrix et al. 1991) found the 

 Great Basin fence lizard (Sceloporus 

 occidentalis biseriatus) to be abundant where 

 soils were drier. It prefers open areas with 

 mounds of soil or debris for perching and 

 territorial display. California kingsnakes and 

 San Diego gopher snakes were also found in 

 drier areas of glasswort (Salicornia 

 subterminalis), pickleweed (S. virginica) 

 and salt grass (Distichlis spicata). 



The salt marsh vegetation changes 

 gradually with elevation, and can be depicted 

 as a series of overlapping distributional 

 curves (Figure 3.2). Almost every species 

 has its peak occurrence at a different 

 elevation band, and the vegetation forms a 

 continuum rather than a set of zones. Still, 

 the presence of shrub-like succulents at the 

 uppermost elevations (Figure 3.3) and the 

 taller cordgrass (Spartina foliosa) at the 

 lowest elevations helps to designate higher and 

 lower marsh habitats. Unlike the drought- 

 deciduous coastal scrub species, the plants of 

 the salt marsh grow through the summer and 

 early fall. Presumably, this is because the 

 wetland plants have access to moisture from 

 tidal waters throughout the dry summer and 

 fall. 



Small mammals also use the drier areas of 

 salt marsh. According to Taylor and Tiszler 

 (Entrix et al. 1991), the western harvest 



28 



