The chaparral shrublands of southern California(Los Angeles and San Diego), and similar sagebrush ecosystems in the Great Basin, are not adapted to the kind of frequent fire typical of the mountain conifer forests in northern California........... Fires in the lower elevation chaparral ecosystems are always crown fires, which kill most of the vegetation............... In the millennia before humans arrived, these ecosystems burned at intervals of 100 to 130 years............Over the past 100 years, dryer temperatures and soaring human populations(people setting fires purposely or accidently) have this ecosystem burning every 20 years............. This high frequency of fire has instigated a persistent switch from chaparral to grass in some areas.................. Frequent fire favors quick germination and spread of forbs and grasses............... Most grasslands in California are not native and thus there are adverse inpacts on native animals up and down the food chain...........Bobcat occurrence is most strongly influenced by avoidance of urbanization and time since fire, suggesting they may be the best indicator of landscape condition for the carnivore guild that exists in this part of the world.................The 10 or so remaining Pumas ins SoCal not only are bottlenecked in to a finite living space by an "erector set" Freeway system but research also suggests that the landscape-scale effects of this ever increasing and intensive fire regime may also negatively affect their ability to persist into the future.................

http://www.sciencedaily.com/releases/2014/08/140806173838.htm?utm_source=feedburner

Landscape dynamics in Southern California : understanding mammalian carnivore response to fire and human development

Jennings, Megan Kathleen

URI: http://hdl.handle.net/10211.10/3830

Date: 2013-02-25

Abstract:

In southern California, many studies have focused on the effects of urbanization and landscape fragmentation on mammalian carnivores. However, fragmentation is not the only landscape-level change that occurs from human development, which has also been linked to shifts in natural disturbance processes, such as wildfire. I use three robust, long-term datasets, including data from remote camera and telemetry studies, to examine mammalian carnivore response to wildfire and increasing fire frequency in southern California. 

coyote traversing burnt chaparral

My analysis of 14 years of compiled remote camera data indicated that, of the seven mammalian carnivores evaluated, bobcat occurrence was most strongly influenced by avoidance of urbanization and time since fire, suggesting they may be the best indicator of landscape condition for the carnivore guild.

Gray fox and puma may be most sensitive to future type conversion, while the mesopredators more tolerant of urbanization (e.g. striped skunk, raccoon, and opossum), may benefit from increases in grassland habitat.

 Analyses of a 10 year dataset of >40 collared pumas showed that, although the relationship between pumas and the landscape was complex, they are able to utilize burned habitats, and post-fire conditions provide habitat for pumas at the individual- and population-level. While puma habitat use responded positively to time since fire, I found a negative relationship between pumas and high fire frequency, suggesting the landscape-scale effects of the changing fire regime may negatively affect puma populations in southern California.

 Finally, using long-term telemetry data from bobcats and coyotes to assess connectivity in an urbanizing and fire-prone landscape, I found that without representing the constrained nature of the habitat, landscape characterizations with regard to urbanization and burned habitat may be inaccurate, especially for bobcats. In particular, landscape connectivity for bobcats was reduced substantially when fire-return interval departure was incorporated in my models. 

The results of these three analyses indicate that it is critical that the shifting disturbance dynamics of wildfire be considered in conservation planning and connectivity assessments in southern California to establish more comprehensive plans that adequately protect landscape integrity and connectivity for mammalian carnivores and other sympatric species..