What’s an Ecoregion?
The WWF, which takes the lead in categorizing and describing such things, tells us that an ecoregion is:
a large area of land or water that contains a geographically distinct assemblage of natural communities that
- share a large majority of their species and ecological dynamics;
- share similar environmental conditions, and;
- interact ecologically in ways that are critical for their long-term persistence.
The WWF recognizes 825 terrestrial ecoregions, 426 freshwater ecoregions and 200 marine ecoregions. From these, the WWF has identified 200 priority ecoregions. The Global 200 are the planet’s most biologically distinct regions; conserving these would preserve the broadest possible diversity of plants and animals. The California coastal sage and chapparal ecoregion is one such ecoregion.
The ecoregion encompasses 14,000 square miles of Southern California and Northern Mexico coastline, as well as the nearby Channel Islands. The Santa Rosa Mountains, northeast of San Diego are included, but the San Jacinto Mountains a bit further north and east are not (they’re part of the California montane chaparral and woodlands, instead). The climate is Mediterranean, which means cool wet winters and hot dry summers. Rainfall ranges between 6 and 20 inches a year.
So. What’s here?
If we weren’t here there’d be lots of coastal and valley oaks, groves of California walnut, lots more sage, of several varieties, coastal grasslands and vernal pools, salt marshes along the coasts and manzanita and toyon up in the foothills. There’d be a lot more California gnatcatchers. There’d be plenty of kangaroo rats, legless lizards and rosy boas. There’d be more butterflies (150-200 different species) and there’d be a bunch more spiders.
We still have all those things — and more, including plenty of endemics* like some of the aforementioned and the horned lizard and the Cactus wren. Out on the islands we have some relicts, too, which are species that are holdovers from long ago. Locoweeds, buckwheats and oaks are relicts out there. The Catalina ironwood used to be everywhere around here, but now it’s only found on Catalina Island. Of course, we’ve tilled under and paved over most of the places those things lived. Just 15% of the ecoregion is intact. The whole ecoregion is practically a relict.
Large swathes of the original habitat are protected within the Camp Pendleton Marine Corps base north of San Diego. The Torrey Pine State Reserve protects one of just two stands of that tree. Other bits of the habitat are intact here and there at parks and reserves in the Santa Monica Mountains and in Riverside County and in stretches of still undeveloped Irvine Company inventory in Orange County. A little bit more has been set aside recently in Crystal Cove State Park, with hiking trails that used to be roads and holiday beach house rentals that used to be homes, more relicts from another time.
*An endemic species is one that is only found in a particular place and habitat and no place else.