Camino Corto Open Space Preservation & Vernal Pools Habitat Biological Resource
Prior to restoration, the 24-acre site contained approximately 4 acres of vernal wetland and 1 acre of riparian or freshwater wetland. These wetlands were surrounded by approximately 19 acres of grassland. The grasslands and wetlands on the site functioned together as a cohesive component of the upper Devereux Slough watershed. The project site thus provides a critical transition zone (freshwater to brackish water to salt marsh) from the Isla Vista Mesa to the north finger of Devereux Slough. The wetland area also provides a critical corridor for movement between the Devereux Slough ecosystem and the Storke Campus wetlands.
The following description of habitats is taken from Olsen, 1992.
Vernal Pools and Flats
Vernal pools are small wetlands frequently supporting unique plants and animals. They form in depressions where the impermeable soil (usually clay) causes water to pond from winter rain. The plants in a vernal pool are unique because they can survive both in flooded conditions and in completely dry conditions. They are often rare or endangered because most of the vernal pool habitat in California has been destroyed, especially in flat coastal areas like Isla Vista.
Olsen's definition for vernal pool follows that of Zedler (1987): a depression filling with water in the winter and becoming desiccated by summertime, and characterized by a special flora. The boundaries of vernal pools are determined by the plants within this flora, in addition to soils and the extent of flooding. The term vernal flat comes from Pritchett (1988) and is useful to describe habitat which is transitional between the grasslands (upland) and vernal pools (wetland). Vernal flats have indistinct boundaries due to fluctuation in annual precipitation. Following several years of good rainfall, vernal flats are likely to be characterized by vernal pool species and tend to exclude introduced grasses and other upland weeds. In drier periods, the vernal flats tend to look like grasslands.
A large portion of the northern part of the site is covered with vernal flat and is designated as the "Eastern Flats". These flats are notable for their substantial population of the vernal pool indicator species Callitriche marginata (wallow starwort), Elatine brachysperma (waterwort), Eryngium vaseyi (coyote thistle), Hordeum californicum (meadow barley), Lythrum hyssopifolia (loosestrife), Plagiobothrys undulatus (popcorn flower), and Veronica peregrina ssp. xalapensis (figwort). A broad band of vernal flat connects the Eastern Flats with the Rush Pool.
The Rush Pool is so indicated because of the prevalence of brown-headed rush (Juncus phaeocephalus). This pool seems to be all that remains of what once was a more extensive vernal wetland that was associated with the Goleta Slough watershed. In addition to the rush, this pool has populations of Eleocharis acicularis (needle spike-rush), E. palustris (spike-rush), and Plagiobothrys undulatus (popcorn flower). The prevalence of the Juncus and Eleocharis palustris indicate a vernal pool that includes some characteristics of freshwater marsh. Pedestrian traffic in the northern half of the parcel has worn paths whose margins support vernal pool species, especially Juncus bufonius (toad rush).
A small patch of Eryngium armatum (coyote mint) occurs on the west-facing slope of the small drainage which runs south between the southern boundary of Isla Vista School and the riparian corridor. This perennial species is usually found associated with the outer margins of vernal pools. Isla Vista marks the southernmost point of distribution for this species (Pritchett, 1988).
Native Grassland
A stand of meadow barley (Hordeum brachyantherum) is found in the southwestern section of the site. In Santa Barbara County, this grass is usually found in vernal pools, but the population mapped here is not. Although not identified in Olsen's study or a previous study prepared by D. Pritchett in 1988, this and other native grass species may be scattered on other portions of the site.
Freshwater Marsh
The arroyo draining into Devereux Slough supports persistent wetland vegetation including willows (Salix lasiolepis), brown-headed rush (Juncus phaeocephalus), and the non-native grass Festuca arundinacea.
Upland
Most of the upland vegetation on the site consists of introduced Eurasian grasses such as Avena barbata (slender wild oat), Hordeum leporinum (foxtail), and Lolium multiflorum (Italian ryegrass). Scattered clumps or individuals of the native coyote bush Baccharis pilularis var. consanguinea dot the parcel. Other noteworthy upland plants include gumplant (Grindelia robusta), everlasting (Gnaphalium californicum), and owl's clover (Orthocarpus densiflorus).
Other Vegetation
Sweetgum eucalyptus (Eucalyptus globulus), and acacias are planted mostly on the southwestern portion of the site and form a conspicuous non-native element of the vegetation. Other exotic and native woody plants have been planted around the site. Most of these are not invasive, but plantings of pampas grass (Cortaderia jubata) in the southeastern section may become a problem.
