CDFW Wildlife Branch 1812 9th Street
Sacramento, CA 95811
Related CDFW Programs
YES! Deer Habitat Management Does Have a Place In California's New Emphasis on "Ecosystem Management"
Following is an analysis of why. We might have subtitled this piece "Searching for environmental-correctness using a species that is often maligned for being hunted." But whether you are a deer hunter or not, the graphic below simply illustrates a widely recognized response by one wildlife species to large-scale habitat change. The species is mule deer, and the changes in question were brought about by the severe wildfire year that occurred in 1987. That summer and fall, there were several wildfires that encompassed in excess of 30,000 acres each in California. While such large wildfires put human life and property at risk, for many wildlife species disturbance from fire enhances long-term ecosystem vitality.
We consider deer in California an "early successional" wildlife species meaning that they rely on an abundance of young/new vegetative plant material that germinates or resprouts following fire. We also use the term "habitat disturbance" to describe a change in plant succession. Herbaceous plants (the grasses and wildflower species), then shrubs, are first to recolonize burned areas. This is followed by what most folks call a forest-- the trees. Hence, the "succession" from grasses/forbs to shrubs to trees.
Where large wildfires occurred, deer populations-- as reflected in part by the change in harvest of deer during hunting season-- began to increase after a three-year lag time, more so than in areas not subject to large wildfires. Deer biologists know the benefits in improved forest habitat condition from fire are greatest from 3-30 years after fire. Beyond that time, vegetation becomes overgrown, or decadent, and declines in value as food and cover to wildlife.
How does this relate to ecosystem management in California?
Deer inhabit nearly all wildlands in the state and we have several decades of data on deer populations and trend (more than for any other terrestrial wildlife species). Because of this, deer are an excellent barometer of habitat conditions, particularly habitat conditions in conifer or hardwood-conifer dominated forest systems. Deer populations go up-and-down in large part in response to the habitats they depend on, and they depend on early successional habitats in California's forests. Deer populations have declined substantially from their historic highs, largely due to declining habitat conditions exacerbated by reduced habitat disturbance from fire. Fire is the most effective mechanism to restore those habitats. The successional change in forest systems has been from a mix of early-mid-late successional habitats to habitats that have less early successional habitat-- this has serious implications to the ecosystem as a whole.
So, an unanswered question is: If deer populations have declined in numbers because of habitat changes caused by succession, how have the 100s of other wildlife species -- as yet largely unstudied-- and sharing the same wildlands as deer, responded to the same changes? That deer populations in areas with large fires increased is telling, because it helps confirm that their habitats in California are overall, on the decline.
If you interact with CDFW wildlife biologists, you may increasingly hear them advocate early successional plant communities on forested lands--not just from fire--but also through land management activities such as timber management, rather than hearing them advocate deer habitat improvement as they did in the past. [To us it's the same thing, but it sounds more ecosystem-correct.]
[For those interested in such details, the data used here for large fire areas included hunt zone data from B2, B6, X4, X6, and D6; areas without large fires included D5, D8, and X11.]