FEMA Rule Change Could Make Tree-felling Easier

Very often, land managers seeking funding for a project look to the Federal Emergency Management Agency (FEMA) for funds. FEMA provides money for fire hazard reduction, and if the project can be presented in those terms, the land managers can apply for a grant.

Until now, if a project seeking FEMA funding was large enough, FEMA asked the project sponsors for an Environmental Impact Report. This made a lot of sense: Fire hazard reduction projects have massive impacts on the landscape and habitat, much of it negative.


Now,  FEMA plans a “programmatic environmental assessment (PEA) to evaluate the potential beneficial and adverse impacts from eligible wildfire mitigation activities funded under the Hazard Mitigation Grant Program (HMGP) and Pre-Disaster Mitigation (PDM) Program.” What this amounts to is that fire hazard reduction projects would be “pre-cleared” from an environmental standpoint. FEMA is planning to make this a nationwide measure.

It would apply to  three types of wildfire mitigation projects to protect buildings and structures on the Wildland-Urban Interface (i.e. where structures are within 2 miles of a wildland):

  • “Defensible space—The creation of perimeters around residential and non-residential buildings and structures through the removal or reduction of flammable vegetation;
  • “Structural Protection through Ignition-Resistant Construction—The application of non-combustible building envelope assemblies, the use of ignition-resistant materials, and the use of proper retrofit techniques in new and existing structures; and
  • “Hazardous Fuels Reduction—Vegetation management to decrease the amount of hazardous fuels; vegetation thinning; and reduction of flammable materials to protect life and property beyond defensible space perimeters but proximate to at-risk structures.”

The first two measures are not controversial, and can reduce hazard with a relatively minor environmental impact. However, the third one – Hazardous Fuels Reduction – is much more problematic for the environment.


Tree removal – for whatever reason – is one of the costliest activities for a land manager. This makes any potential source of outside funding attractive.  FEMA is one such source. So if any tree-felling project can be presented as hazard reduction, it has a chance of obtaining such funds. Not having to do an environmental impact report would make the money more easily accessible.

However, removing  trees also has a significant environmental impact, which can be greater or lesser depending on the size of the project, the topography of the site, and the ecological system that would be affected. Some of the impacts:

  • Hydrology: Removing trees affects water flow and can lead to problems with erosion
  • Slope stabilization issues: The root systems of trees – especially older, mature trees that may have intergrafted roots – stabilize slopes. Removing trees can contribute to slope failures years – even decades – later.
  • Carbon sequestration: Trees capture and store carbon, fighting global warming. Felling trees stops them from collecting the carbon, and  returns it to the atmosphere.
  • Toxic herbicides: In many of these projects, managers plan to use large amounts of herbicides to prevent tree regrowth. This can end up in the soil and water, and also affect people, pets and wildlife using the lands.
  • Pollution: Trees and vegetation help fight pollution, particularly particulate pollution, by trapping particles on their leaves until they’re washed to the ground by rain.

And of course, removing trees affects the beauty and recreational value of these areas. It’s only by evaluating the environmental impact of individual projects that FEMA can determine if the negative environmental impact would be worth the hazard reduction – if any. Ironically, many of these projects would actually increase fire hazard, because removing the trees encourages growth of scrub and grass that ignite more easily and support fast-moving fires.

We’ve been concerned because we think that Native Plant “restoration” projects are often presented as hazard reduction projects. In 2008, FEMA received such an application for tree-felling in Sutro Forest. More recently, FEMA was asked to fund the removal of hundreds of thousands of trees in the East Bay.


FEMA is accepting comments until August 18th, 2014 – this coming Monday. The comments have to be submitted at their website (not by email). Here’s how:

  1. Go to the Federal eRulemaking Portal: http://www.regulations.gov
  2.  In the Search space that comes up, input FEMA-2014-0021
  3.  Then click on Open Docket folder at the right.
 (Or try this link: HERE )

They’re not interested in comments that look like a mass mail campaign, so to have an impact, you would have to write a the comment individually.

Great horned owlets in eucalyptus. San Francisco. Janet Kessler

Don’t Cut Trees in the Nesting Season!

This year, the issue of tree-trimming or cutting during the nesting season was highlighted by the sad destruction of black-crowned night herons’ nests when the Oakland Post Office decided to get its trees trimmed. Five young herons were injured, others may have died. The tree trimmer potentially faced criminal charges, but was so remorseful – and so willing to pay for the care of the baby herons – that everyone was relieved when he didn’t.

Most people just don’t know that it’s a bad idea to trim trees (or worse, remove them) during the nesting season. Even aggressively trimming undergrowth could damage or destroy birds’ nests.  In San Francisco, the season extends approximately from February to September, depending on many factors including the weather.

Each year, Wildcare, a wonderful organization that rehabilitates hurt or orphaned wildlife,  gets a deluge of baby birds during the summer. Most of  them are displaced by tree-trimming or removal.

2012-04-11 bewick's wren nesting

Birds nests are difficult to spot, even for experts. Herons’ nests are large and noisy, and the Oakland Post Office staff surely knew the birds were there. But most birds hide their nests. Unless they are huge ones like nests of hawks or owls, the parent birds need to conceal their young from predators. Humans, who typically aren’t really looking out for them, would usually miss seeing them altogether. It may take even experienced birders hours of observation to be sure. Nests of hummingbirds, for instance, are around the size of a quarter. They’re common in San Francisco but very difficult to spot.


Here’s Wildcare’s page  “Stop! Don’t Prune Those Trees!”  It explains the problem in a user-friendly way, and also gives references of two bird-friendly arborists who can do emergency work if needed.

 “Spring (and summer!) are busy baby season— procrastinate now!

When is wildlife nesting? There is some variation, but most wild animals have their babies in the spring, between March and June. However, many species will also have a second brood in July or August if food supplies are sufficient. If you can plan to trim your trees in the winter months, you can completely avoid the possibility of damaging a nest. It’s also a healthier time for the trees, when the sap has gone down and trees will be in their dormant phase. Call WildCare at 415-456-7283 if you’re unsure when it is a safe time to trim or remove a tree. “

The Golden Gate Audubon Society has published an excellent brochure:  Healthy Trees, Healthy Birds that is available as a PDF on their website. Here are pictures of the brochure (the download will be clearer and can be printed).

GGAS Healthy Trees Healthy Birds brochure 1

GGAS Healthy Trees Healthy Birds brochure 2


Disturbing – or worse, destroying – a birds nest is illegal. It’s a strict liability offense punishable by up to six months in jail and/or a $1,000 fine per offense.  There are laws at the Federal, State and City level. Here’s what they say:

  • Federal Migratory Bird Treaty Act. This applies to over 1,000 bird species, including many that are found in San Francisco. It makes it ” …illegal for anyone to take, possess, import, export, transport, sell, purchase, barter, or offer for sale, purchase, or barter, any migratory bird, or the parts, nests, or eggs of such a bird…” (“Taking” means to harass, harm, or pursue a bird.)
  •  California State Code 3503, 3503.5: ” It is unlawful to take, possess, or needlessly destroy the nest or eggs of any bird, except as otherwise provided by this code or any regulation made pursuant thereto.”  California State Code 3503.5 relates to birds of prey: ” It is unlawful to take, possess, or destroy any birds in the orders Falconiformes or Strigiformes (birds-of-prey) or to take, possess, or destroy the nest or eggs of any such bird except as otherwise provided by this code or any regulation adopted pursuant thereto.”
  • San Francisco County Municipal Code 5.08: It’s unlawful “to hunt, chase, shoot, trap, discharge or throw missiles at, harass, disturb, taunt, endanger, capture, injure, or destroy any animal in any park...” (with exceptions for small rodents like gophers).

The general rule is to stay 50 feet away from song-bird nests, and 500 feet from raptor nests.


Sometimes, trees are removed because they’re in poor condition – dead or dying. Those are often the very trees that birds love, especially those that nest in cavities. Like this flicker (a kind of woodpecker) nesting in a half-dead eucalyptus tree. If you weren’t watching very patiently, you would have no idea that a family of young birds (three in this case) were being raised here.

The eucalyptus-tree nest hole of the red-shafted flicker - San Francisco. Janet KesslerPLAYING SAFE

The only safe way is to NEVER cut trees or thin dense bushes during the nesting season – and even when working in the off-season, typically September to February, to be very observant and watchful before starting work.

Young Great Horned Owls being raised in Eucalyptus tree

Mount Sutro Forest Isn’t Diseased or Dying – It’s Natural

This post is reproduced, with permission and minor changes, from SutroForest.com

sutro forest canopy June 2014 sm


In the Sutro Stewards blog last month, Craig Dawson (who is its Executive Director) wrote a post claiming that the forest was in dire straits, infected with funguses and beetles: specifically, Anthracnose, armillaria, phytopthora, wood decay fungi, the snout beetle and the tortoise beetle. It concluded: “The bottom line is that we cannot expect much of the declining forest to recover from the condition it is currently found in, rather we can expect further widespread die-off. The dying trees will quickly pose a significant hazard within a year or two as we have already witnessed.”

It sounded alarming.

We sent the link to the article to a number of experts. None of them thought it was particularly serious. (One academic ecologist called it “…pure twaddle…” ) Nor did they agree with its conclusion that the forest would therefore decline.

  • “The diseases and insects mentioned in the Sutro report could be found in any forest…” (from a certified arborist and plant pathologist)
  • “The description of common conditions of eucalypt trees on the part of Mr Dawson’s piece seems to me solid as such—a description—but unconvincing as an argument that pretends to show some state of pathological emergency in Sutro…” (from an environmental science professor)
  • “This is amateur plant pathology at its best….” (from an urban forester)
  • “…faith-based botany…” (from an urban forester)
  • “This is certainly not the first time I have seen someone want to use a disease threat as a roundabout way to get some politically inconvenient trees removed.” (from an academic plant pathologist)


Some commented specifically on the individual fungi/ beetles. We also investigated ourselves, using the UC Davis website.

  • Anthracnose: “anthracnose is found on the leaves of many plants…” [In San Francisco] “sycamore leaves are filled with anthracnose…” (We would also note the UC Davis website says, “In California, anthracnose rarely causes permanent damage to plants except for elm trees.”)
  • Armillaria: “…definitely all over the place in the coast ranges and is even rampant in Golden Gate Park.” (This does not indicate a dire disease requiring intervention, especially tree-felling.)
  • Phytopthora: We could find no references to phytophthora in eucalyptus in California.
  • Wood decay fungi: “..these are mostly associated with older trees. The pictures represent Trametes versicolor – mostly found on dead wood, very rarely on living trees; Laetiporus gilbertsolnii – common on living Eucalyptus and oaks…” (Again, there’s no indication that these are reason for alarm.)
  • Eucalyptus snout beetle: These beetles feed on eucalyptus leaves. According to UC Davis’s website, “Eucalyptus snout beetle is controlled biologically by Anaphes nitens, an introduced parasitic wasp. No further control is necessary.”
  • Eucalyptus tortoise beetle: Also a leaf feeder, these beetles don’t usually kill trees. From the UC Davis website: “Unsightly, tattered leaves are usually just an annoyance that does not appear to threaten eucalyptus survival or health.” Since some tattered leaves in a forest setting are quite natural, we don’t think this is a problem.

Following a recent walk through Sutro Forest, Dr McBride (Professor Emeritus, UC Berkeley) noted that the forest looked healthy and thriving, with no evidence of the feared decline. He pointed out that in a naturalized setting like this one, we should expect some number of trees to do poorly or even die, as the forest “self-thins.” Furthermore, he said, without fungi and other creatures as part of the forest ecosystem, we’d be up to our eyeballs in dead logs.

fungus on a stump - sutro forest - june 2014

We have to say that in our years of frequent walks in the forest, in all weather and at all times of the year, most of these fungi and beetles are rare. Rare enough, in fact, that when we see fungi or mushrooms (the fruiting body of some fungi) we take pictures. We found a few leaves with evidence of tortoise beetles (semi-circular “bites” from the leaves), but they were few and far between. So far, we have not been able to find leaves showing the elongated perforations made by snout beetles.

few leaves have beetle holes

We asked about hollow trees. Dr McBride said that unless the remaining wood is less than 30% of the diameter, hollows in trees did not weaken them. “A tube is structurally one of the strongest forms,” he said. The life of a tree is in its outer layers. The center of a tree essentially provides structure. (And – hollow trees are great wildlife habitat.)


The Sutro Stewards article also includes a picture of a stand of trees with a defoliated canopy, implying that is typical of the forest. It is not. This picture at the start of this article, taken in June 2014, is actually much more representative of the conditions in Sutro Forest. (Here’s a picture of the forest taken from Twin Peaks.)

sutro forest from twin peaks - June 2014

The stand portrayed in the article does exist. It is on the lower part of the East Ridge – right above an area where UCSF has removed a lot of trees and understory as part of their “fire hazard” action in August 2013. This has made the forest there much drier and less able to retain moisture – particularly since this is on a steep slope near the edge of the forest. Dr McBride considers that the trees’ intergrafted root system may also have been damaged during the work, making the stand much more vulnerable. However, the trees do seem to be recovering, currently with epicormic growth.

gradually recovering defoliated eucalyptus on east ridge of sutro forest


But rather than indicating that the forest is diseased and trees should be removed, it suggests much more caution. The removal of smaller trees and understory and damage to root systems can stress trees, reducing the moisture available and increasing wind damage. Instead of making the remaining trees more healthy by “releasing” them, it can make them less healthy – as we see on the lower part of the East Ridge. Similar impacts are visible in Glen Canyon, where a lot of clearing has been going on – exacerbated by pesticide use.

Furthermore, with the normal fungi present, and with the usual damp conditions in this cloud forest environment, chopping down trees doesn’t help reduce fungi, it only spreads it around.

Damp Forest on Mt Davidson – Tony Holiday

This is another of our Park Visitor series: First-person accounts of visits to our San Francisco parks. This photo-essay is by Tony Holiday, a San Francisco hiker and blogger.  It’s adapted from his blog, Stairways are Heaven and published with permission. (Visit his blog for more pictures, and for the second post that details the route out of the forest down the Bengal steps.)

It’s high summer now, and elsewhere in California, fires have started. In our forests, it’s damp, even wet. We were struck by the contrast between the wetness of the forested area, and the dry open space adjacent to it on Mount Davidson. This is the cloud forest effect: The trees harvest the moisture from the fog and keep the forest cool and damp.

DAMP FOREST by Tony Holiday

The #36 Teresita stops at Mount Davidson Park’s main south entrance (Dalewood & Myra) where a steep trail climbs to the openspace part of the park. I love this trail: forested to start out, with a vast view to the east a little way up.

Here’s the south trail head.

4334894_orig - 1 South trailhead

And a small offshoot trail…

8176020_orig 2 offshoot trail

I climbed out of the forest to the open space.

7570617_orig 4 curving around

7082684_orig 3 climbing to the open space


This is the open space part of the mountain, with views to the east  and south over the city.

5027966_orig 5 view east

7960836_orig 8 looking south

2513967_orig 9 openspace bench

3514794_orig 10 view north

7411013_orig 11 view north

It’s a good place to pause for tea and admire the view…

5093980_orig 12 pausing for tea

Climbing 22 steps from the open space brings you to the plateau on top of the mountain with the 103-foot cross.

2858920_orig 16 summit cross


Down 22 old wood steps from the north side of the cross…

4275316_orig 17 old wood step start down from the side of the monument

… there’s a short trail…

5819148_orig 19 ferns and a damp trail

2691069_orig 20 down to a main trail

…then 12 more stone steps to the next main trail down.

1660245_orig 22 foot of one of the short stone stairways

Up here the trails were damp or muddy, including some actual puddles.

7940036_orig 23 muddy upper trail

Another short stone stairway:

572463_orig 24 anothr stone stairway

Following the trailing down, enjoying the cool, lush forest…

6294871_orig 25 trees and rocks

3227413_orig 26 down through the forest

… and the greenery below the trail…

4428599_orig 27 below the trail

4787964_orig 28 forest view

The trail went winding down…
3864834_orig 29 winding around

… and it was just me, the forest, and birdsong.

8763025_orig 30 just me, the forest, and birdsong

The forest was peaceful…

806571_orig 31 peaceful and cool

… as I followed the narrow and winding path to its end.

1526681_orig 33 narrow and winding

Love the ferns here!

6534432_orig 34 love the ferns

Natives and Newcomers Can Get Along – Dr. Scott Carroll

Dr. Scott Carroll of UC Davis, and the founder of the Institute for Contemporary Evolution in Davis, spoke at the Commonwealth Club as part of the series “The Science of Conservation and Biodiversity in the 21st Century.” His main message:

Mixed communities, consisting of non-native and native species of plants, animals and other organisms, are here to stay. We need to find ways to live with these new neighbors. Once they are introduced, they will evolve, and so will the species that were already there. Trying to eradicate “invasive” and non-native species is expensive, likely to cause unforeseen problems, and have uncertain success – in part because evolution will make a moving target of an introduced species.

Read on for notes from Dr. Carroll’s talk. (There are also links to his Powerpoint presentation, and to the audio recording from the Commonwealth Club.)



(Notes from a talk by Dr Scott Carroll)

Plants and animals have always moved around the planet, but gradually enough that the world had distinct bio-regions with their own indigenous species. About 500 years ago, shipping greatly increased the pace – people deliberately or inadvertently introduced species into new places. It’s what people do.

historical bioregions - dr scott carroll talk at commonwealth club 2014Invasion biology” as a discipline originated with Charles Elton’s 1958 book. The response to Invasion Biology is a deeply emotional one, coming from a sense of how an ecosystem should look and how species should interact. The transfer of species around the globe has been called the greatest ecological spasm since the extinction of the dinosaurs. But is it?

brown earthIn fact, there’s been a much more important change. The amount of wilderness on the earth’s surface has fallen sharply, from around 50% in the 1700s, to around 20% by the year 2000. The rest is cultivated or range lands or built-up. We need to look at invasion biology – permanently mixed communities of native and introduced organisms – in the context of that land use change.

These land use changes drastically altered the environment for all species, with a major impact on all species and ecological relationships. Natural selection picks new winners: Changed environments have different fitness criteria, so plants or animals that were successful before may become losers. If populations decline, it reduces their chances of evolving to meet the new environment: fewer individuals mean a smaller gene pool, fewer potentially beneficial random mutations, and fewer offspring. Some species go extinct.

But others don’t. They adapt and evolve and use the resources the new environment or new introduced species provide. Some players in these novel interactions have the capacity to solve their own problems, restoring more balanced kinds of ecological interactions than one would expect from the terms “invasion” and “takeover” and “destruction.”


How do we define an “Invasive Species”?

It’s a species not native to a bio-region that are:

  • Introduced
  • Reproducing independent of our assistance (naturalized, in the case of plants) and
  • Very specifically, they are doing something that we do not like.

This means that it has to be defined with reference to who “we” are. The definition of “invasive” must include who is doing the defining.

In some cases there’s broad agreement. Nearly everyone agrees on fighting invasive disease-causing insects, for instance. In the case of plants and trees and animals, people may diverge sharply in their opinions. Eucalyptus is an example; those who dislike it make consider it invasive; others would disagree vehemently.

The ‘eradication’ arm of Invasion Biology – i.e. those looking to destroy introduced species, perhaps 90% of invasion biologists – is fighting a very difficult battle. It’s extremely expensive, and risks doing much more harm than good.


What are the problems of Eradication policies? Here are 8 issues:

1. It’s extremely expensive, both in time and effort.
Even in cases that seem possible – eliminating rats on an island, for instance, it may be an uphill battle. The first 75% are easy to kill. The next 20% are more difficult. By the time you’re down to the last 5%, your team is exhausted and you’ve “spent $3.2 mn of your $2.7 mn budget.” You haven’t seen a rat recently, so you leave. And then – the 2% of the rats that remain reproduce and repopulate the entire island in five years.

2. It doesn’t necessarily solve the problem.
Even if you succeed in killing off the invader, it won’t necessarily bring back the ecosystem that existed before. For instance, soil conditions may have changed so instead of native plants returning, other non-native plants – or nothing at all – grows.

3. It can disrupt ecological systems.
For instance, an introduced predator may have been keeping an introduced plant-feeding prey species in check. Once the predator is eliminated, the prey may destroy vegetation and the ecosystem as it exists.

4. It can disrupt replacement ecological relationships that existing plants and animals may have developed with the “invaders.” They may be providing food, seed dispersal, pollination, cover and other ecosystem services. For instance, if a native plant species is declining because of climate change, an introduced species can provide food for birds, animals and insects.

Loggerhead_sea_turtle_hatchlings_caretta_caretta public domain5. Sometimes, the new species provide a new ecosystem service to existing species, and destroying them would hurt the native species too. For instance, beachside non-native trees may protect turtle hatchlings from artificial lights that can disorient them, and so improve their survival rates. Or the non-native species may be controlling a different non-native species that might otherwise become a pest.

6. Trying to kill off non-natives can drive them to evolve resistance to the agent used to kill them. This is a common problem when herbicides are widely used to kill “invasive” plants.

7. Killing non-natives may reduce biodiversity of the area by reducing the pressure on native species to diversify and become new species.

8. The new species may directly increase biodiversity in the area, and eradicating them reduces this biodiversity.


rabbit public domain clipartA story that illustrates many of these problems is that of the myxoma virus, used to control Australia’s huge rabbit population.

The Iberian (or European) rabbit was introduced into Australia by Europeans in the 19th century, and eventually bred so prolifically that it started to destroy the environment. In the 1950s, the Australian government introduced the myxoma virus, a New World rabbit disease lethal to European rabbits. Initially, that killed 99.5% of infected rabbits, and the population plummeted.

But the surviving rabbits continued to breed until the next time the disease went around. With each successive outbreak, the mortality declined. Frank Fenner, the scientist overseeing the project, found that the virus was attenuating – becoming less lethal – while the rabbits were developing resistance to it. Eventually, each outbreak killed only 20% of the rabbits in the area.

In 1952, a landowner in France introduced the virus on his farm to control rabbits. Soon it spread across that country, and then to Britain, where it killed 95% of the rabbit population.

Large Blue Butterfly - wikimedia commons cca3 - PJC&coThis led to the extinction of the British population of the Large Blue Butterfly. The butterfly is an unusual species whose caterpillars mimic larvae of the ant species Myrmica sabuleti, so they get carried into the ant’s nests where they eat the larvae. Rabbits cropping meadow-grasses had kept them short, providing ideal conditions for the ants. With the rabbits gone, the grass grew, ants declined, and the Large Blue Butterflies vanished.

iberian lynx wikimedia commons cca25-klia Meanwhile, the myxoma virus also reached the Iberian peninsula, where it devastated the native rabbit population. The rare Iberian lynx, which depends solely on rabbits as a food source, became critically endangered, and the Iberian eagle – which also preyed on rabbits – declined sharply. Aquila_adalberti wikimedia commons cca3Officials are looking to vaccinate the wild rabbit population against myxomatosis.

Another unforeseen consequence occurred on Macquarie Island. This desolate Australian island was a breeding place for seals and sea-birds. Human introductions of rats (inadvertently), rabbits (for food), and cats (to combat the rats) impacted the sea-bird populations. The eradicators first introduced fleas to the island as a vector for the myxoma virus, and then the actual virus in 1978. Then they eradicated the cats. However, the cats had been hunting the rabbits, and now the rabbits multiplied out of control reversing years of conservation efforts. The myxoma virus had likely attenuated, and failed to control the rabbit numbers. The rabbits grazing destroyed the hillsides where the penguins nested, causing landslides that harmed their breeding success.


The story of the soapberry bug is more encouraging.

Soapberries are a plant family with a number of separate species, two of which are invasive vines in Australia. They invade along water-courses, and grow over trees in those areas. One vine species reached Northern Australia around 1680; the other, much taller species arrived in Eastern Australia around in the 1920s and has become particularly damaging to the forests there.

soapberry bug smSoapberry plants have fruit of varying sizes with nutritious (to insects) seeds at the center. Soapberry bugs are specialized soapberry eaters, with long beaks to pierce the fruit and reach the seed. The beak-lengths of these bugs are evolved to fit the particular species of soapberry they prey on.

When the introduced soapberry plants arrived in Australia, the native soapberry bugs had beaks too small to use the new food source. But with time, they started to evolve.

In Eastern Australia, it took 30 years for the soapberry bug’s beak to evolve from 7 mm to 7.5 mm. That doesn’t sound like much, but an increase of 0.5 mm doubles the number of seeds the bug can reach.

In Northern Australia, where the bugs have had over 300 years to evolve, their beaks have grown from about 5.5 mm in length to around 8 mm – exactly the length they need to attack the introduced soapberry plant. They match as well as if the soapberry plant was native.

It’s the same species of bug.

One interesting experiment would be to see if breeding the two strains would help the Eastern bugs grow a longer beak and control the soapberry vines better. Dr. Carroll recommended stopping the plant eradication program in Northern Australia to protect the long-beaked soapberry bugs there while evaluating whether interbreeding the two bug strains could accelerate the evolution to slow the spread of the large vine in Eastern Australia.


Dr. Carroll stopped his presentation there because time ran out. But if you would like to see his PowerPoint slides, they are here (in ppt and pptx formats). The Commonwealth Club’s Audio recording of his talk is also linked here. (There’s a lively question and answer session at the end, which isn’t included in these notes.)

Powerpoint presentation in ppt format: S Carroll Commonwealth Club Jan 2014

Powerpoint presentation in pptx format:S Carroll Commonwealth Club Jan 2014 (2)

Audio recording from Dr Carroll’s Commonwealth Club talk: http://www.commonwealthclub.org/events/archive/podcast/scott-carroll-conciliation-biology-13014

McLaren Park: Stairways, Wildflowers, and Great Blue Heron

This is another of our Park Visitor series: First-person accounts of visits to our San Francisco parks. This is by Tony Holiday, a San Francisco hiker and blogger. It’s adapted from his blog, Stairways are Heaven and published with permission.

Go HERE for the original post on McLaren Park (and more pictures).


1 Starts from Visitacion Ave.

Passing on recent pix of a McLaren Park stairway that some SF stairway walkers may not be familiar with: The longest in the park with 195 steps, and starts up at the dead-end of Campbell Ave  in the Visitacion Valley neighborhood. It’s set back a bit from the street, thus slightly “hidden.”

195 steps

195 steps

Down into Vis Valley neighborhood

Down into Vis Valley neighborhood and out to Campbell Ave

It climbs past Visitacion Valley Middle School and up to Visitacion Ave. When you reach the top, continue up steep Visitacion to divided Mansell.

hidden stairs at dead end of Campbell

South of Mansell is the Visitacion Valley neighborhood. North of Mansell, to the east of the park, is the Portola ‘hood.

From the foot of the stairs, this time downhilled on Campbell a couple of streets to Delta. Left on Delta to the next street up, Tucker, and onto the skinny, steep, rough concrete walk (seven steps to start).

Delta pathway Tucker to Tioga


At the top of this pathway, the next cross-street up is Tioga, then Wilde. Turn left on Wilde to Ervine for a steep curving trail into the park, the old observation tower above.

Vis Valley below

You can’t see the stairs until you’re partway up (about 56 steps) at the top of which are a couple of Philosopher’s Way musing stations and view benches.

Musing Station on the Philosophers Way

There’s a seriously steep trail off the stairway, also up to the view benches.

Steep trail up from the stairway

Especially love the south, open space part of McLaren with big sis San Bruno Mountain across, everything green and wildflowery now at both parks.

san bruno mountain in the distance

San Bruno mountain in the distance

What is this flower seen south of Mansell?

[Webmaster: Gaillardia?]


Unfortunately one of the nearby musing station plaques had been graffitied-upon; hope there are ways to remove the paint from the artwork.

Check out these daisies all over the place, just north of the tennis courts, with Bernal Hill in distance.

Daisies on the lawn, Bernal Hill in the distance

A favorite trail descends to Lake McNab that starts a short distance below the tennis courts, north of Mansell.

Trail to Lake McNab

It’s steep, switchbacked, hard-packed dirt.

Trail sign climbing back up

Critters seen: a squirrel (too far away), a lizard (too fast), and this guy.

great blue heron gopher-hunting

McLaren is around 318 acres and the third largest park within SF city limits. However, since the Presidio’s a national park, some people don’t include it when talking about acreage, even though it’s larger than Golden Gate Park. So one is likely to hear city park McLaren still spoken of as being the second largest SF park.

Great Blue Heron - long-legged beauty

The Logic of Ecological Change – Prof Art Shapiro

Recently, UC Davis Professor Art Shapiro gave a talk at the Commonwealth Club.  It was a tour-de-force. He described it as a very quick resume of a course he’s been teaching for 40 years at UC Davis.

The takeaway: The conventional wisdom about ecology is often wrong.

[You can listen to the one-hour audio recording of his talk HERE.]


eco-jigsaw2Nativists idealize an ecosystem as a community of plants, animals, fungi, and other organisms that have evolved together over many thousands of years in a particular place so that they fit like a complicated jigsaw – the balance of Nature. (We’ve heard them use phrases such as “lock and key” to describe the effect of this co-evolution.) When non-native and invasive species enter, nativists believe, they destroy this intricate mechanism, resulting in an impoverished and simplified ecosystem with fewer species and no natural balance – and even the dire possibility of ecosystem collapse. They talk in terms of plants and animals that “shouldn’t be there” – usually, immigrant species brought in by humans.

But it’s not often true. What the scientific data show is that “communities” of that interdependent kind are unusual. Instead, most ecosystems are groups of plants and animals that happen to be in a place where they can thrive. When they interact, it’s usually because of “ecological fitting” – they can use the other plants and animals in that area to help them survive. Depending on how ancient they are, communities may include tightly co-evolved mutually interdependent multispecies systems. But these make up only a fraction of the community as a whole.

Anise swallowtail butterfly breeds on fennel

Anise swallowtail butterfly breeds on fennel

Here’s the evidence against the concept of tight-knit interdependent “communities”:

1. There’s no functional difference between a heritage ecosystem and one with exotic species. If there was, scientists should be able to tell an undisturbed “community” from an invaded one without knowing its history. In fact, they can’t. There are no consistent  functional differences once an “invading” species has been established. Some ‘invaders’ can drastically transform the systems they enter – an example is cheatgrass in the Western deserts, which greatly amplified fire risk there. But most do nothing of the sort.

2. Species recolonize open land at different rates.Species move, communities don’t.” If a landscape is wiped clean – say by glaciers or a volcanic eruption – nature begins to move back in almost immediately. The pollen record allows scientists to understand which species of trees arrived at which time. It shows that tree-species move individually, not as communities.

3. Species that now don’t exist in the same place did so in the past, which would not be true if plants and animals normally lived in fixed communities. One example: the wood turtle and the southern toad are not found in the same areas now – but the fossil record shows that in the past, the ranges did overlap. This couldn’t have happened if they needed to be part of different communities. Vast areas were occupied in the past by “no-analogue” communities – ones that simply don’t exist anywhere at all today.

He ended by pointing out that we – humans – are an invasive species. So are most things, at least at one time.

Read on for detailed notes from Professor Shapiro’s talk at the Commonwealth Club.

Again, you can listen to an audio-recording of the whole talk HERE (on the Commonwealth Club website).




(The talk was dedicated to Prof Shapiro’s late neighbor, Steven Warnock.)

commonwealth club motto

Commonwealth Club motto

The talk was in three parts: The first laid out the historic context for two opposing schools of thought about ecology. The second examined the data, and concluded that the evidence supports Gleason. The third part looked at the future, which includes climate change.


Here’s the conventional wisdom about ecology, associated with Frederic Clements: Plants, animals, insects, fungi and microscopic creatures form interdependent groups, or “communities.” The process by which this happens is “co-evolution” (sometimes described as evolving a “lock and key”), leading to an ecology where all the species fit together like a jigsaw puzzle. (“Co-evolution” is associated with Peter Raven and Paul Ehrlich, who described it in butterflies and plants that evolved together.) If an area is disturbed, it will go through a predictable process of “natural succession” that will lead to a stable “climax” situation, with all its species again interacting as a community.

This stable ecosystem is sometimes called “the balance of nature.” Tamper with  it, this theory says,  and you could destabilize the whole community, even leading to ecological collapse.

assemblageThe opposing view, associated with Henry Gleason, is that plants and animals do not necessarily form ecological communities. Instead, groupings or “assemblages” of plants and animals occur mainly by accident. They happen to arrive in that space at that time, and find conditions that allow them to survive and thrive. The species in such an assemblage will interact, not because they co-evolved, but because they find an opportunity to do so.

These theories about how species fit within an ecosystem were quantified when several ecologists – including the famous Robert McArthur – introduced mathematical models that looked at populations of plants and animals and their interactions. They used these models to look at Species Packing – i.e., how many different species of plants and animals could live in a particular ecosystem.  Assembly rules says that the distribution of plant and animals species in a given area isn’t random: both competition and cooperation between plants and animals affect what you find. Competing species can’t all live in the same area, but their niches can overlap. Where they do overlap, the two species may evolve more differences (“character displacement“) so they compete less. These mathematical models assumed a condition of equilibrium, i.e. stability. Opponents have argued that ecological niches are seldom stable because the physical environment is not stable for very long.

R.H. Whittaker introduced the idea that the levels of dependency could vary within communities. For any two species, you could assign a number: +1 meant that the species needed each other to survive; -1 meant that they could not live in the same space.  He speculated  that these relationships tended to be distributed in a bell curve – meaning that most species in a group didn’t depend on the presence or absence of another species. But some subsets of the community were tightly integrated.

How adaptable are living things? They can evolve, but only in certain ways.  Niche conservatism is the idea that most species cannot change very much or very fast in response to changes in their ecological niches.

The idea of co-evolution was fine-tuned with John Thompson’s concept of Geographic Mosaics. Co-evolution between two species can happen differently in different  geographic areas. So, for example, a plant in one place might depend totally on one insect for pollination, but elsewhere, the same species of plant might find alternative pollinators available. Such Fine-Tuning is the opposite of Niche Conservatism – and both occur in Nature.


Cladistics (i.e., the system of showing how related species evolved from common ancestors) provided a way to test the Ehrlich-Raven co-evolution hypothesis. If one kind of animal or plant developed into a separate species (“speciation”) then did the plants and animals depending on it also co-evolve into a separate species? There was no evidence that this happened. Co-evolution was a lot sloppier and more unpredictable than that!

Every time you see two organisms working together, it doesn’t necessarily mean they are co-evolved. Dan Janzen, a great tropical ecologis, pointed out that organisms could be taking advantage of niches and resources that appear through  Ecological fitting, with no history of coevolution at all. We see this happen when introduced pests attack native plants, and native insects attack introduced plants, forming brand-new associations. It happens all the time.

pacific reed grass under eucalyptus

Pacific reed grass thrives in eucalyptus fog drip

Is there really a difference between “intact” ecosystems and ones that are disturbed or invaded? Mark Sagoff pointed out that if there really is a functional difference between “invaded” and “co-evolved” ecosystems, then scientists should be able to tell them apart without knowing their history.

“The theory that evolutionary processes structure ecosystems and endow them with a mathematical organization (e.g., rule-governed patterns that ecologists can study) has the following implication….scientists should be able to tell by observation whether a given ecosystem is heavily invaded or remains in mint condition…

“In fact, once non-native species have become established, which may take only a short time, ecologists are unable by observing a system to tell whether or not a given site has been heavily invaded. Invaded and heirloom systems do not differ in pattern or process, structure or function, in any general ways.”

There’s more evidence against the idea of stable interdependent communities as the norm in nature. For example: pollen core data shows that trees recolonizing lands after glaciation don’t move in “communities.” The tree species migrate at different rates. Only those species that have mutualistic relationships move together (for example, mycorrhizae and trees).

WoodTurtle public domain Ltshears sm“Communities” are like still shots from a movie. They show a set of relationships at a particular point in time. That doesn’t mean the relationships are stable or unchanging. Many species show different sets of relationships in the past. For instance: at present, the wood turtle and the southern toad have completely different ranges – but in the past, those ranges overlapped in places. In the UK, workers building Hadrian’s Wall nearly 2000 years ago left middens that have remains of beetles of species now found only in Lapland.  When an event that wipes out an ecosystem and recolonization starts, it takes trees 50-100 years to leave a pollen signature. Bufo_terrestris public domain Norman Benton smBeetles that can fly get there in  months to a few years.

If communities were stable groupings of interdependent co-evolved species, then we would expect to see the same communities repeated in similar conditions. But in fact, we often see different groupings in similar conditions.


Decisions about what ecosystems should look like are subject to human preferences. For most people, what they grew up with is “normal.” But the world has changed. The climate is changing.  The pool of available species has increased enormously. In terms of trying to “restore” an earlier ecosystem – there’s no going back.


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