Tuesday, October 23, 2007

Ecological causes and effects of SoCal fires: Initial thoughts

There are numerous wildfires currently blackening southern California. The short term response has to be to the fire itself. Save the people, save the pets, save the homes and the businesses. But what should be the response when the fires are out? Ruibiuld everything exactly as is was? That is the most likely outcome. After a disaster, people want to rebuild, regardless of how likely it is that disaster will happen again. But how likely is it these fires will return? What ecological factors played into this disaster, what ecological effects can be expected and what lessons should we draw from all of this?

I feel it is important to raise these issues before everyones attention moves on and we fail to learn from previous mistakes. I'll appreciate your input and comments.

With no further ado:

Ecological Causes:

1. Obviously the big'un is the Santa Ana Wind, the hot dry wind that blow-dries out of the Great Basin and over southern California every year. The topography and climate of coastal southern California, combined with the Santa Anas make for fires pretty much every year. It is being reported that the Santa Ana's are stronger and more persistent than usual this year. It is not yet known, so far as I know, if the Santa Ana's are expected to be stronger every year now that the Great Basin's climate is turning much hotter and drier.

2. California has had an unusually dry year this year. Unusual meaning "in comparison to the last 150 years." This year may turn out to be unusually wet as compared to the next 150 years, because, as mentioned, the climate of the southwest is drying.

3. A lot of these areas have many times the natural fuel-load. The last 150 years are important, because that is how long we have been suppressing fires in southern California. This unusually wet period allowed for a lot of biomass to build up, and not burn off, because we would not let it burn.

The natural time between fires in most of these areas is a few decades. Fires would pass through, burn off much of the fuels without destroying the local ecology because in most cases, the previous fire was recent enough to keep this fire from getting too hot. By putting out every fire we could for so long, we allowed the fuel load to build up to the point that the fires now get incredibly hot and spread incredibly fast. Some of the areas currently burning have burned recently, but the mean time since the last fire is much higher than what is natural.

4. We tend to build our settlements and structures without regard to the fact that we are building in a fire maintained ecology, and another fire will come. By failing to take that into account, we make things that much harder for firefighters and those who need to evacuate. It is like building in a floodplain and expecting your house to not get washed away every once in a while.

5. The climate is changing and the southwest is becoming more of a desert. When wet areas dry out, the vegetation eventually burns off.

Ecological Effects:

1. California is a world center of biodiversity, and quite a few of our species are found nowhere else. Many of the native plants and animals are already endangered by habitat loss, invasive species, pollution and climate change. Most of our natural areas are fragmented by human edifices. The native populations could deal with the comparatively mild natural wildfires of the past. Smaller, more fragmented and already declining native species with small ranges may well have trouble keeping a foothold in areas burning as hot and wide as the current fires.

I have a colleague who studies a species of native mouse found primarily in San Diego County. This year he could find almost none of his mice because their habitat is turning to desert. He did find them in a few places. In the last two days some of those places have gone up in smoke.

2. Fuel loads in the areas currently burning will be reduced, which is both good and bad. Good in that future fires will have less fuel. Bad in that all that fuel load was sequestered carbon, which is now in the atmosphere, and because the drier southwest won't have as much vegetation, that carbon is not going to be taken back out by the same land. My guess is, without having seen any numbers, that total carbon output from these fires will actually be quite minuscule on a global scale, and we are better off without all that tinder lying around.

3. If the rains in SoCal do get started in a month or two, we can expect some serious erosion from all the areas that have been stripped of their vegetation.

Lessons, not just for SoCal, but for the country:

1. Don't just let fuel build up until it explodes. Areas like this need to have some plan for how to get rid of fuel. My personal preference is controlled burns at times of year when the fire is easier to keep in hand. We can't keep pretending we can keep fire based ecologies from burning forever.

2. Notice that climate change is a serious problem now. Stop making the problem worse.

3. Take fire risk into consideration when deciding where and when to build. Developers should be legally responsible for planning their developments such that they are not putting residents and firefighters at risk. Planners should disallow building in areas that cannot be defended from fires.

Monday, October 22, 2007

.01% of California burned in past two days

Area of California is= 160,000 mi²

Acres per square mile= 640

Area of California in acres= 102,400,000

Acres burned in California in past two days= 100,665 (according to Bloomberg)

Portion of CA burned in past two days= 100,665/102,400,000= .0001= 0.01%

Sunday, October 14, 2007


This is a really cool invention my friend Brent brought to my attention. It would be incredibly useful in places like PNG where solar doesn't work because it is always raining.

Friday, October 12, 2007

Informed Consent Form

There are no known risks or discomforts associated with participation, other than the possibility of annoyance that it takes longer to read the informed consent form than to complete the questionnaire.

Thursday, October 11, 2007

Summary of reproductive biology, as conveyed by my four year old neighbor:

1. "I was in my mommy's belly"
2. "You was in your mommy's belly."
3. "Everything was in mommy's belly."
4. "Except fish. They don't do it."
5. "Then you crawl, crawl crawl down to, um, butt? Come out!"
6. "That cool, right?"

Tuesday, October 09, 2007

Depth vs. Depth

One of the questions on the exam I am grading asks the students to pick a physical characteristic of ocean water (pressure, density etc.) and draw a plot of that against depth into the ocean, to show how the measurement changes with depth.

One of the students decided to draw a graph of how depth changes with depth. This would technically be a good answer, except that when she plotted depth against depth she got a parabolic curve.

Friday, October 05, 2007

Sensory Bias

Last week I was trying to describe to my animal behavior students what sensory bias was. I told them that particular species, because of the particulars of their sensory organs and neurology, have a much stronger neurological response to certain shapes, patterns or colors than a member of most other species would. I told them that the sensory biases of a species affect the evolution of traits in potential prey, predators, competitors and mates.

I think this makes a fine example.

putting up with neighbors

Yesterday my friend Akaba gave a talk about her work with various rodents on the neural basis of sociality (and variation therein.) One of the interesting points that came out in the conversation that followed it that many of the researchers there had the impression that in the groups we study, the more social species are more docile when handled. I think this is cool, and makes a lot of sense. A big part of being social is just not getting pissed off too easily, or at least not responding disproportionately when you do get pissed off.

I hope she follows up on this.

Wednesday, October 03, 2007

Ladybug larva

I've mentioned in the past the usefulness of ladybug larvae in controlling aphids. A few people asked me to take a picture of one, so they would know it if they saw it. Here it is.

Tuesday, October 02, 2007

Glossary of Science

The following is the glossary I put together for my students from my lecture notes for the first section of Animal Behavior.

Adaptive- conferring a positive fitness relative to competing traits, in the current environment

Altruistic- costly to the individual behaving but beneficial to some other individual or group

Behavior- What an animal does, generally in response to an external or internal stimulus.

Behavioral Ecology- The study of behavior in relation to its adaptive value in environmental context.

Cryptic Female Choice- Female behavior, morphology, and/or physiology influencing which of the males a female has mated with end up being the genetic father of the female's eventual offspring.

Direct Fitness: The number of descendant individuals produced by an individual, times the degree of relatedness of those descendants to that individual.

Evolution: Change in the genetic makeup of a population over time.

Fitness- reproductive success

'Good Genes' Polygyny- System in which females choose among mates based on an honest signal of male quality, rather than for any resources, care or territory the male has to offer.

Hamilton's equation: rB-C>0 where r is the relatedness between the individual who acts and the individual who benefits from that action, B is the benefit in direct fitness to the recipient and C is the cost in direct fitness to the actor.

Heritable- more similar between related individuals than between unrelated individuals.

Inclusive Fitness: Direct fitness plus indirect fitness

Indirect Fitness: The number of non-descendant relatives produced by an individual, times the degree of relatedness of those relatives to that individual.

Kin Recognition: The ability to, or act of, classifying some individuals as related to oneself, and others as unrelated to oneself.

Kin Selection- non-random differential reproductive success arising from heritable variability in traits which affect the direct fitness of an individual's kin, rather than of the individual itself.

Lek Polygyny- Mating system in which males gather to display for females and females examine the males and mate with those which are most impressive.

Levels of analysis- The different ways we can attempt to explain the same behavior, including its adaptive value, it phylogeneitc background, the organismal mechanisms underlying it and the developmental and genetic factors leading to it.

Mating Strategy- everything an individual does to determine when how and with whom it mates, and to ensure that mating produces offspring.

Mating System- a description of how the species tends to mate, and which males mate with wich females under what circumstances. Female Defense Polygyny, Polyandry and Monogamy are examples of mating systems.

Monogamy: In biology, one male mating with one female. Monogamy can be social (the pair act as though they only mate with each other) and/or genetic (the pair actually parent all of each other's offspring)

Polyandry- Mating system in which one female mates with multiple males.

Polygamy- mating system in which an individual mates with multiple individuals of the opposite sex. Includes polyandry and polygyny.

Polygyny- mating system in which one male mates with multiple females.

r- stands for relatedness. Defined as the portion of two individual's genotypes which are identical because of common ancestry.

Reproductive Strategy- anything and everything an individual does that functions to allow it to reproduce. This includes its production of gametes, how and when and with whom it mates, parental care and so on.

Selection- non-random differential reproductive success arising from heritable variability

Selective Pressure- environmental factor(s) that determine adaptive value of different traits

Sexual Selection- non-random differential reproductive success arising from heritable variability in traits directly affecting sexual reproduction

Sociality- the tendency to live in groups of conspecifics

Sperm competition- "competition between sperm of two or more males for the fertilization of an ova" (Parker 1970).