23-Sept-2014 Mt. Hamilton, California

Location of Mt. Hamilton

Before this field trip I didn’t know that, to the untrained eye, California foothill pine (Pinus sabiniana) resembles ponderosa pine (Pinus ponderosa) when looking at Google Street View.  I can now confirm this phenomenon.  This is the problem with winging it in unknown ecosystems and having no time to seek out local expertise and advice.  Mistakes will be made.

I was looking for ponderosas on Mt. Hamilton.  They were documented there by Griffin & Critchfield (1976) and a 100 year old record in the Calflora database.  I was using Street View to confirm that they were still present as well as accessible from the road.  Most of the trees I'd seen on Street View looked like ponderosa pine to me, but turned out to be foothill pine.  I did ultimately find two ponderosas, but they were terribly spindly and had little in the way of cones to offer.  Live and learn.

View from Lick Observatory atop
Mt. Hamilton

The day wasn’t a total wash, however, since I enjoyed the views from Lick Observatory and found a splendid stand of big-cone pine (Pinus coulteri) just east of the Mt. Hamilton peak.  The gigantic cones (big as my head!) lying in the roadside ditch were definitely harboring spiders, but I didn’t collect specimens since this wasn’t my target tree species.  And can you imagine trying the peel the scales off of one of these monsters?  But now we know: spiders use Pinus coulteri cones, too.

My foot and a P. coulteri cone, each about 25 cm long.

Spider web and exuvium in P. coulteri cone.

Maps of the California Sampling Sites

If you've been reading my California posts and wondering, "Felton?  Where the heck is that?", these maps are for you.  Map 1 shows the location of all of my ponderosa pine (Pinus ponderosa) fallen cone sampling sites in California from 2014.  Note that the sampling sites are divided into two regions, Santa Cruz County to the west and the foothills of the Sierra Nevada mountain range to the east.  Map 2 zooms in on the seven sites in Santa Cruz County, and Map 3 does the same for the two sites in the Sierra Nevada foothills.  Click on any map to enlarge.  Maps were made with GPSVisualizer.

Update: Below the maps, I've added links to my posts about the California sites.

Map 1. Location of 2014 Pinus ponderosa fallen cone sampling sites in California.

Map 2. Location of 2014 Pinus ponderosa cone sampling sites in Santa Cruz Co., California

Map 3. Location of 2014 Pinus ponderosa cone sampling sites in the Sierra Nevada foothills of California.

• 10-Sept-2014 Columbia Historic State Park, Columbia (Tuolumne Co.)
• 12-Sept-2014 West End of East Zayante Road, Felton (Santa Cruz Co.)
• Testing Cone Sampling Efficiency In California
• 21-Sept-2014 End of Bean Creek Road, Scotts Valley (Santa Cruz Co.)
• 23-Sept-2014 Mt. Hamilton (Santa Clara Co.)
• 3-Nov-2014 East Whitlock Road, Mariposa (Mariposa Co.)
• 10-Nov-2014 Martin Road, Bonny Doon (Santa Cruz Co.)
• 18-Nov-2014 Quail Hollow Ranch, Felton (Santa Cruz Co.)
• 25-Nov-2014 Quarry Road East Spur, Felton (Santa Cruz Co.)
• 1-Dec-2014 Quarry Road West Spur, Felton (Santa Cruz Co.)
• 9-Dec-2014 Randall Morgan Sandhills Preserve, Scotts Valley (Santa Cruz Co.)

21-Sept-2014 End of Bean Creek Road, Scotts Valley, California

Location of Scotts Valley sample site

A virtual cruise down the main thoroughfares of Scotts Valley via Google Map Street View left me optimistic that I could home in on 20 ponderosa cones in no time. Reality on the ground was another matter.  The modest ponderosa woods along the southeastern side of the intersection of Scotts Valley Dr. and Mt. Hermon Rd. were easily accessible and not posted as private property, yet I found virtually no cones beneath the sizable trees within. Time today was again of the essence since I was only arriving on site in the afternoon and would have the limitation of waning daylight. 

Michael Stipe may have written Stand to be a nonsense bubblegum song, but when I turned a 180 on the disappointing grove and looked up to see this towering lone pine across the street, well, "...think about direction..." started playing on my internal soundtrack.  Loads of open cones on a thin layer of needles dotted the ground beneath this beautiful giant. Jackpot!

Today's cone source

Urban cones

Processing the cones in Felton’s Skypark, I was entertained by the several peewee soccer games underway (“The goal is that way!”) and a first birthday party being held for a boy who seemed to have one too many drunk uncles.  With all this going on I was lucky to find an open picnic table.

I collected 13 spiders from 20 cones, all via the tapping method.  As with the previous sample, which was from an urban section of neighboring Felton, Oecobius sp. juveniles were the most numerous spider present in the Scotts Valley sample.  I also collected a pair of Drassodes neglectus, a juvenile ant mimic (Micaria sp.) and an assortment of other juveniles.  Not bad for what otherwise looked like a barren, lifeless patch of urban dirt.  And I completed my work before dark.

Testing Cone Sampling Efficiency In California

Yesterday in my post about Columbia Historic State Park I mentioned that I was using my cone sampling time in California to test the efficiency of my cone tapping method.  A friend has asked me to elaborate on that.  I am happy to do so.

When I began tapping cones back in 2008, I devised a sampling method on the spot that I've been using ever since.  It consists of simply whacking the cone against the inner wall of my net while holding the net against my thigh, so as to create a solid striking surface.  (If you try this, note that it helps to have coins or keys in your front pocket so that any prickles on the cone scales don't pierce your skin.)  I hold the cone upside-down and as close to its base as possible, and rotate it a few times in the course of giving it numerous whacks.

How good is this method at dislodging all the spiders from a cone?  That's the question I'm trying to answer with these California samples.  Here's how:  After tapping a cone as described above ("tapping method"), collecting the dislodged spiders and clearing the net, I next used pliers to pull the cone scales from the core and let the scales and any remaining spiders fall into the net ("peeling method").  Before searching the debris for spiders, I gave the remaining cone core a few more whacks into the net.

The number of spiders I collect from cones by the tapping method divided by the sum of the "tap" and "peel" spiders gives me a measure of the efficiency of the tapping method.  In equation form:  Tapping Efficiency = T/(T+P).

The peel method may not be a perfect control, since usually only the cone's small basal scales can be completely pulled free from the core.  Larger scales tended to break off near their bases rather than be pulled completely free.  This means that there is a possibility that some spiders may still remain in the cones even after they've been peeled.  However, the peel method has been effective in dislodging additional spiders from previously tapped cones, so it's effective to some degree.

Below are a few photos to help you visualize what I'm describing.

Here's a photo showing what a typical peeled ponderosa pine cone looks like.  Notice the silken spider refugium that I've drawn a circle around.  In the case of this particular cone, tapping it hadn't expelled the spider resting inside that refugium.  Subsequently peeling the cone didn't force the spider out either, but it did make it possible for me to spot it, open it and collect the spider.

This spider refugium and its inhabitant were only visible to me after I peeled the cone.

Peeling occasionally exposed tiny refugia between a cone's tightly-packed basal scales.  I never found any of them inhabited.  Was that because they were vacant before I picked up the cone, or because tapping had already expelled their inhabitants?  The mystery remains.

Tiny, empty refugium exposed by peeling.

 If I've left any questions unanswered or any points unclarified, or if you have ideas for building a better mousetrap, please feel free to drop me a note in the comments.

12-Sept-2014 West End of East Zayante Road, Felton, California

All you need is one good pine...

The next opportunity to collect came with a time limit; I had to be back in Palo Alto to attend an evening wedding rehearsal dinner.  This meant that a return trip to the foothills of the Sierras was out of the question.  Luckily a few tantalizing marks on Griffin & Critchfield’s ponderosa pine distribution map led me to believe that ponderosas are, or at least were in 1976, present in scant quantities in nearby Santa Cruz County.  A bit of citation mining in Griffin & Critchfield and some googling led me to discover the existence of the Santa Cruz sandhills, an unusual 7,000 acre area of sandy soils supporting a disjunct population of ponderosas.  (Damp soils and redwoods are the norm in this coastal environment.)  Based on those dated resources and a more recent report from The Sandhills Alliance For Natural Diversity, I decided to aim for the town of Felton and cruise the area until I found a productive tree.

...to get a full sample of cones.

The main way into Felton from Route 17 is via Mt. Hermon Road, which online resources indicated would be sprinkled with ponderosas.  Alas, there seemed no safe place to stop and collect along that very busy road.  I thought my worries were over when I found a few sizable ponderosas decorating the edge of the shopping center parking lot where Mt. Hermon Road meets its end at Graham Hill Road, but as happens so frequently with urban pines, most of the cones had been removed by groundskeepers. 

I decided to continue on to the “census-designated place” west of Felton called Bonny Doon, which from my reading seemed a good place to continue prospecting for ponderosas.  And how could a person resist the promise of Pine Flat Road?  Sadly, there were no pines on Pine Flat Road.  I should know by now not to take road names literally, since they seldom reflect the reality of the vegetation they transect.  

The disappointment of the Bonny Doon digression faded quickly, however, after I returned to my starting point in Felton.  There, only a few blocks from the “cleaned-up” shopping center trees, I discovered an impressive lone ponderosa with dozens of fallen cones beneath it (location map).

Oecobius navus female.

Setting up at a picnic table in the nearby and very busy little Felton Covered Bridge County Park, I quickly found this set of cones to be teeming with an unusually high concentration of spiders: 58 spiders from only 21 cones, or 2.8 spiders per cone!  In eastern Washington, I’d found a mean of 0.24 spiders per cone with the maximum from any site of 1.3, so you can imagine my surprise.

I got my first peel spiders today, but only four -- not enough to account for the high overall tally.

The most common species by far was Oecobius navus (Oecobiidae), a presumably naturalized species which comprised about a third of my specimens.  Oecobiids have an anal tubercle fringed with long, curving hairs arranged in a way that is reminiscent of a fountain or a flower.  I love this, not only because it makes the family easy to ID, but who doesn't love a spider butt that encourages poetic description?

Tiny refugium between the cone's
basal scales.

Incidentally, the “human dimension” at this park was quite entertaining.  Besides the usual flow of moms with toddlers stopping by to ask “whatcha doin?” that I encounter in urban parks, I had interesting conversations with a homeless man retrieving multitudes of returnable beer bottles and cans from the groundcover in the woods beyond the picnic tables, as well as with a police woman who pointedly asked me what I was doing.  I suppose my little alcohol vials could look suspicious to an officer of the law, especially given the presence of all those beer cans in the ivy; undoubtedly she was keeping an eye out for public drunkenness and drug dealing. 

Which brings me to the small group of people with the look of hard living about them who I suspect were responsible for many of those discarded returnables.  One of the men informed me quite directly that I was using “their” table and that he wanted to share it. I explained why I wasn’t prepared to move or make room (“delicate biological specimens”), and they grudgingly moved on to a different table.  Happily, several women from the group came back later to find out more about what I was doing, declared it a cool thing, and told me their spider stories, so our interaction ended on a positive note.

Vital equipment: table, cloth, net, pliers, bag o' cones, Diet Pepsi

So many spiders per cone really increased my cone processing time, and so I worked until the last possible moment before I figured that I needed to head back north. Except that I hadn’t counted on the closure of Mt. Hermon Road, the most direct return route, by repair crews! In retrospect I should have continued south into Santa Cruz and picked up Route 17 north there, but I dislike backtracking and Route 9 north via Saratoga looked straightforward enough on the map, so that’s the way I went.  Little did I realize how twisty-windy slow Route 9 is, nor did I anticipate the construction stoppages I encountered along the way, all with less than a gallon of gas left in the tank! Needless to say I was relieved to emerge from the forest in Saratoga virtually within sight of a gas station. The rest of the return trip was uneventful, and we made it to the rehearsal dinner on time and enjoyed it very much. 

* Related: 10-Sept-2014: Columbia Historic State Park, Columbia, California

10-Sept-2014 Columbia Historic State Park, Columbia, California

My home away form home (Palo Alto, CA) in relation to the
theoretical location of local ponderosa pines. Map source.

Finding myself unexpectedly in Palo Alto, California on family business for the final quarter of 2014, I took the opportunity to conduct an experiment on the efficiency of my cone tapping method (more on that here).  Since I've focused most of my west coast sampling on ponderosa pine (Pinus ponderosa) cones, it was the logical species to use.  But where to find them?

A little Googling turned up a map in Griffin & Critchfield (1976) showing that in central Calif., ponderosas are concentrated along the western spine of the Sierra Nevada range.  This made sense, since the Sierras are the southern extension of the ponderosa-rich Cascades range in the Pacific Northwest where I've done so much cone spider sampling.  The map also showed a smattering of trees near the coast in Santa Cruz and Monterey counties.  Most intriguing!  But those mysterious coastal ponderosas would have to wait, since intrigue wasn't the only factor driving my choice of sites today.

Columbia Historic State Park

Ponderosa pines bordering
parking lot

Wanting to maximize the likelihood of finding plentiful cones quickly between the morning drop-off and evening pick-up of a family member at the San Jose airport, I selected Sonora as my destination.  Google Map's Street View seemed to confirm Griffin & Critchfield’s old (1976) report that ponderosa pines should be plentiful in and above this Sierra Nevada foothills town.  After consulting a Tuolumne County map obtained from a visitor information office in Sonora, I decided to first explore the nearby Columbia Historic State Park (location map).  As luck would have it, the lower parking lot had it all: ponderosas with lots of open cones on the ground, picnic tables with at least some shade (it was a scorcher of a day), public bathrooms and drinking water.

Spider-filled cones in the ditch.

I filled a paper grocery bag with 35 cones collected from the forest floor and the shallow, Acer macrophyllum leaf-filled ditch separating it from the parking lot, spread my sorting cloth on a picnic table, and proceeded to process the cones.

Among the 13 spiders I collected were two juvenile Euryopis sp. (Theridiidae).  In eastern Washington, Euryopis formosa are only reliably found in ponderosa cones, so this is an interesting find.  One diminutive specimen was lost to a gust of wind, and I had to chase the shade by moving to a new table several times, but otherwise the day went smoothly.

One of several Kibramoa sp. (Plectreuridae)
females present in the cones.

Hurtling back through oak savannas, then the fruit and nut orchards of a dusty San Joaquin valley (lighted highways signs reminded me not to waste water during this period of drought), I stopped in Manteca (what a name for a city!) for a restorative dose of El Pollo Loco before making a bee-line back to Mineta San Jose International Airport just in time to pick up my passenger.

To my knowledge, this blog post constitutes the first time that spiders have been reported in the fallen cone microhabitat in California.

23-Dec-2014: Documenting Dutch Cone Spiders

Sample site. Click photos to enlarge.

BREAKING: The Netherlands has cone spiders too!  I've long suspected that if spiders use the fallen cone microhabitat in the USA, they probably use it elsewhere, too.  Because why wouldn't they?  But it was just an untested assumption until a recent trip to the Netherlands, during which I was able to squeeze in a few hours of cone sampling.

Corsican pines dropping open cones on Waalsdorpervlakte

My sampling sites were a pair of neighboring groves of exotic Corsican pine (Pinus nigra var. maritimus), apparently planted mid-20th century.  I wasn't crazy about sampling cones of an introduced species, but these were the pines I had access to, so these were the pines I sampled.

The trees were located on the western boundary of Waalsdorpervlakte, located in Wassenaar, Netherlands (Lat. 52.112532, Long. 4.332721).  The Waalsdorpervlakte is part of the dune complex that lies between The Hague and the North Sea.  In the area where I sampled, the dunes have been stabilized by grass, oaks and poplars in addition to the pines.

The fallen cone microhabitat

The cones I sampled were situated on a thin layer of pine needles over fine sand or on grass topped with some combination of oak leaves, poplar leaves and pine needles.  I collected between 10:45 a.m. and 12:45 p.m. under partly sunny skies, air temp 11-12 C with 25 kph winds from the SSE gusting over 35 kph (The wind was making nearby radio antennae "sing".).

Two spiders from one cone. For scale, the inner diameter
of the vial is 8 mm.

Corsican pine cones may be tiny (~ 5 cm long), but they weren't too small for Dutch spiders!  I tapped 20 cones into an old pillow case (never leave home without your net...) and got 9 spiders.  Two cones contained two spiders each, five cones contained one spider each, and twelve cones contained no spiders.  Cones also often contained fine sand, tiny flying insects, mites, woodlice and the occasional beetle.

Not knowing the local regulations on collecting invertebrates, to say nothing about getting them past airport security and USA customs, I opted to just photo-document the specimens as best I could, then return the live animals to their cones.  This means that I can't be certain of their identities beyond noting the presence of crab spiders and what look like dictynids.  However, it was enough to confirm that there are cone spiders here.  I hope this discovery will inspire local spider enthusiasts to start tapping conifer cones!

Beware armed storks!

Incidentally, although I was collecting in a country where people don’t own guns for self-defense, gunfire serenaded my collecting adventure.  It turns out that there’s a shooting club just down the trail from my collecting site.  Other than that, passers-by were friendly and inquisitive and either understood and accepted my pidgin Dutch explanation of what I was doing, or tactfully retreated from the crazy lady.  Either way, nobody interfered with my work.

Dutch Keywords: spinnen, spin, krabspinnen, Den Haag, dennenboom, Nederland, dennenappel, Meijendel