Hello students.  This is plants and animals of Southern California.  And we've just passed through the Santa Monica Mountains where there's been several burns in the last 20 years since I've been here.  And so I wanted to talk a little bit about the vegetation that follows a burn.  On the slopes of the hills within an hour of [inaudible] maybe not in the desert but the places that are pretty heavily vegetated, almost every species that lives there is somehow able to repopulate after a fire otherwise it wouldn't live there because it would have been driven to extirpation because there's so many fires.  And then the Santa Monica Mountains or the lower slopes of San Gabriel's or the Santa Susana Mountains we have pretty frequent fires.  And it's a matter of debate how frequent they were before Europeans came.  Now most of the fires occur because people light them.  They like to light them when the Santa Anna winds are blowing because then you get the biggest conflagration.  But probably historically the fires were not lit then.  Like Native Americans probably would have lit the fires at some other time of year.  And lightning storms would have hit, lit the fires not when the Santa Anna's were blowing but, you know, probably months earlier.  That's when the vegetation's the driest.  It hasn't rained in 9 months or something.  And the, a lot of those, especially those scrofulous things, you know, they have really a lot of wax on the leaves.  Those scrofulous things and also drought deciduous things they tend to have lots of sticky oils and resins on them.  And those things don't easily biodegrade.  And so as you get more fuel load building up, as these plants grow then there's all of these waxes and oils that are sort of sitting out there and little twigs and stuff like that.  And it's just really, really flammable.  And so you get immensely hot fires in chaparral stand that is pretty old.  Now the intensity of the fire varies a lot by the topography because of fire breaks.  Both natural fire breaks like riparian zones that dissect the landscape and just sort of the general topography of the landscape.  And also by manmade fire breaks, usually roads or ones that were deliberately put in there to slow fires down.  And then also fires, you know, they burn a lot hotter going uphill than they burn going downhill.  So you just get a lot of heterogeneity in how much burning there was on the landscape.  But anyway what I want to mainly talk about is after the fire.  So sometimes after a fire but not all the time after a fire then the next spring you'll have just a huge flowering of plants that are herbaceous.  Most of the species are annuals.  But there's a substantial number that are geophytes, that is like bulbs and roots and things like that that come up.  And they'll be stimulated to bloom by the fire itself.  The annuals, their seeds were stimulated to germinate by the smoke primarily of the fire which is kind of different than the shrubs.  Shrubs are also stimulated to germinate, many of them, and they, but they have much bigger seeds.  And those seeds are stimulate to germinate by the heat of the fire which kind of breaks down the outer part of the seed wall, something like that.  But anyway, the first year after a fire, the first spring there's a possibility for this big flowering forth that's dominated by fire followers, fire followers.  And these are species that primarily germinate after a fire.  So even one year later there won't be that many of them germinating because there's no more smoke.  And so they are capitalizing on that first year after a fire.  They make huge fields of flowers, lots and lots of seeds.  And most of those seeds are going to lay dormant in the soil until the next fire which could be 100 years off.  And we have a lot of species that do that that are annuals.  Now it doesn't happen every year.  And I guess, and it doesn't happen in every place.  And I think part of that has to do with how much rain there was between the fire and when the flowering season would have been.  Like if you happen to have a drought winter after a fire then they germinate but they never make it to flowering which is sad since they've waiting 100 years for the next fire or 20 years or however long it was.  Now also in this first year after a fire the alien grasses are tend to be kind of pounded back.  And that's because grasses in general don't have seeds that last very long.  And so alien grasses, you'll have some healthy individuals that are producing lots and lots of seeds but you won't have that many individuals the first year after a fire.  But then the second year and the third year it doesn't take long for those few individuals that did germinate after the fire to have grandchildren that repopulate the area with alien grasses.  And so one idea is that if the fire frequency increases too much then we'll tend to have type conversions from shrub lands to alien annual grasslands or prairies.  There's other aliens that also come in after a fire.  So mustards tend to have long live seeds.  And so after a fire you might see a whole mountainside that's covered with alien mustards.  A big yellow showy thing.  And then the geraniums seem to do great no matter what like Erodium cicutarium does great, fire or no fire.  Now let's move on to a group of plants that are perennials.  And you might think of them as short lived perennials.  Some of them are herbaceous, are not woody like penstemons are not woody.  Others are kind of woody.  For instance bush poppy is woody or poodle dog plant, that's woody.  And these are fire followers in a sense too.  But they're not, we don't usually call them fire followers.  I usually call the annuals fire followers.  And these ones are stimulated by fire.  They're not that common.  But they are not the big showy things of the first year.  They're kind of from year two to maybe year six, something like that.  They produce lots and lots of flowers.  They can come to dominate the hillside for a short period of time until they're outcompeted by plants that we might think of more like the climax plants that were there before the fire and will be there ten years after the fire.  Among these plants there's some other ones we find not associated particularly with fire but they do have this opportunity to kind of do well during those first few years, like year two and three and four.  And I would include California broom or deer weed in that group, California broom, same species as deer weed.  That come in after a fire, it's a legume, it fixes nitrogen because of its relationship with rhizobium bacteria.  And it contributes a lot of nitrogen then to that future ecosystem.  Remember the fire would have burned up a lot of stuff and would have vaporized a lot of the nitrogen.  So in fact, the smoke that's stimulating the seeds of the annuals to germinate, the key component of that is NOX, nitrous oxides.  There's also the revegetation of other bigger shrubs.  And this happens by two mechanisms.  There's resprouting and resprouting is where the root crown of the shrub sends up new branches after a fire.  Like for instance Laurel sumac is a great resprouter along the Malibu coast here.  Those things, they could be 1,000 years old.  And after every fire they just resprout.  There's quite a number of species that are resprouters.  The small drought deciduous things tend not to be so much resprouters because they don't have very stout roots.  Whereas evergreen things are more likely to be resprouters although not all evergreens are resprouters.  For instance there's a lot of ceanothuses that we might think of as sclerophyllous that are not resprouters.  There's other ceanothuses that are resprouters.  There's some manzanitas that are resprouters and other ones that are not resprouters.  There's relatively few species that are both resprout and also vigorously reseed.  So reseeding is when after a fire the seeds germinate especially well and you get lots and lots of seedlings coming up.  California broom is a good reseeder.  And there are manzanitas that are good reseeders.  Black sage is a good reseeder.  There's one species that super abundant, super common in the California chaparral and that's chamise.  It's both a reseeder and a resprouter.  It resprouts great and it also reseeds pretty darn well.  So these plants then take time to grow.  But eventually after five or six years they are [inaudible] again.  And then they start and then they have progressed down the road of outcompeting some of the plants that came in right after the fire.  They're just taking up space and they're damaging just because they rub against them and stuff like that.  They're also probably taking up water and nutrients.  And they might even be shading them, some.  And so then you return to the type of vegetation that existed before the fire.  On north facing slopes and a little bit higher up we'd get hard chaparral.  Here on the coast with a south facing slope you'd get a lot of coastal sage scrub.  And then some of this coastal sage scrub is probably getting converted to alien dominated plant communities, herbaceous plant communities because the fires are so much more frequent now.  All right, well that's all I have to say about that.