Nature Notes from Big Creek, 2001

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January 2001 February 2001 May 2001 July 2001August 2001September 2001 December 2001

January 2001

The Kirk fire burned through the Big Creek drainage last fall, creating large cleared areas. Some of these areas have been colonized by pampas grass. The seed probably came from the highway corridor, which is just a few miles south and west, and which has heavy stands of this invasive grass. We saw the small plants last spring but did not recognize them as being pampas grass until recently. It is likely that this grass will now become established in areas of the backcountry, away from the highway. It is possible that many of the plants will not survive; winter frost and summer drought may kill many of them, but survivors may persist in protected areas such as crevices and south-facing drainages. Reserve steward Feynner Arias has been working hard to remove as many plants as he can find but the numbers are great and we have access to only a part of the infested area. Feynner has also found some new French broom (Genista) plants. We can't figure out how those seeds got here, but they could have come in many years ago as broom seeds can last in the soil for many, many years.

The pampas grass invasion shows how new plants become established in an area: There is a major disturbance such as fire which opens up bare ground. Then just the right winds or animal movements bring in seeds from a source population nearby. In many cases new invading species have an advantage over the resident native plants; they lack parasites and specialist herbivores such as scale insects, moths and beetles, which normally keep the plants' growth in check. This is one reason new invasives sometimes take over and displaces resident natives. It is also a reason why invasive plants sometimes contribute very little to the natural food chain; they don't provide much food to resident herbivores or insectivores. Sometimes invasives provide a new type of habitat; for example Eucalyptus trees provide a perfect habitat for roosting Monarch Butterflies. Pampas grass also provides an unusual habitat but I don't know if any resident animals use it.

In August a Cooper's Hawk attacked the chickens in our yard here at the mouth of Big Creek. This hawk was very persistent, trying to reach the chickens through the wall of the coop. A few days later reserve steward Rohana Mayer found the hawk dead near the beach, clinging to a stick, very skinny as though it had starved. She brought it in and Kim added it to "the road kill museum" (her collection of animal study skins that she uses for teaching school children). Just the other day we found another dead cooper's hawk at the beach. It had been dead for a few months and probably was the mate or sibling of the first hawk. Its feet were also wrapped around a stick, indicating that it died while perched. I wonder if they were both sick with some disease? Or did they just starve?

"California spring" has started again this season. The green sprouts are slowly covering the ground, the banana slugs are out, and there is a huge invasion of fruit-eating birds! Up on the ridges we have an exceptional crop of madrone berries, and Martin Cody, a bird expert from UCLA, says he has never seen so many frugivorous birds together on one tree! Cedar Waxwings, Hermit Thrushes, Varied Thrushes and American Robins are most abundant. I've also seen flocks of Kinglets and other insect-eaters. (11-24-00)

   

 Madrone berries at Highlands Camp. They taste pretty good! 11-28-00

 The madrone trees are laden with berries. 11-28-00

February 2001

Our "wet" fall has become a "dry" winter, with only the second storm of the season ending last week. The creek is running at low levels, and after rising about a foot and a half, is quickly dropping down to dry-season flow. Plant growth has been greater than usual by mid-January, with a good early rain and lots of sun. But many seedlings, including those I planted on the bridge construction site, have withered up. However, perennial plants on soil patches (where we are revegetating landslide material just south of Big Creek) seem to be thriving. The patches are mostly covered with hedge nettle and sagebrush, and some mysterious herbivore has defoliated the hemlock!

There are flocks of up to 75 Band-tailed Pigeons in the reserve, larger than last years' flocks but smaller than those of 1999 and 1998. Birds, including pigeons have devoured the madrone berries growing up on the ridges. The seeds, after passing through the birds' digestive systems, are spread far and wide, each with their bit of "fertilizer". It could be a good recruitment year for this beautiful tree.

Huge waves pounded the coast during the last storm, splashing high up on the beach and moving large boulders that have been in place for at least 15 years. The mouth of Big Creek is blocked by a set of boulders, forming a pool upstream. When this usually happens the sand or gravel gets washed away by the creek, but these boulders are so large it may take a large flood to move them. Waves like these can be hard on seals, particularly the elephant seals. A nature-documentary film crew was working at Piedras Blancas during the storm and saw the young seals being tossed and battered by the surf. The hour-long film will be shown next summer on PBS, as one of "The Living Edens" series. The show will feature the natural wonders of the Big Sur coast, and includes scenes from Big Creek, the Hastings Reserve in Carmel valley, and other locations in the area. (1-24-01)

May 2001

I just spent part of the afternoon chopping mustard, thistles and hemlock on a patch of ground we are trying to restore to native vegetation. Last spring at this time a rocky, sparsely vegetated slope was buried by Caltrans, who deposited 20,000 yards of slide material from an adjacent slide (the Big Creek slide of February 2000). Caltrans and the contractors were very cooperative in saving as much topsoil as possible. When the slide material was graded onto the rocky slope, Caltrans re-deposited the topsoil in large patches, which may be seen about ¼ mile south of the Big Creek Bridge. Now, one year later, I am attempting to ensure that the area will grow back with natives. The soil patches are predominantly covered with native hedge nettle, lupine, and California sage, but also contain some mustard, hemlock and milk thistle. The in-between rocky surface is mostly barren, but is being colonized by a grass species that I don't yet recognize. My goal with chopping unwanted species is to prevent them from flowering and reseeding. One thing I noticed today was that the majority of the milk thistle plants were on the north upslope end of the area, near a stand of dried thistle stocks from last year. It seems clear that last spring I made the mistake of allowing a patch of thistles to flower and set seed, creating a problem this year, which I am striving to correct.

Erin Avery, a UC Santa Cruz student, is doing an experiment in the reserve grasslands. She marked out several pairs of meter-square quadrats, and applied Phos-chek fire retardant to one of each pair. This is the orange retardant that the airplanes drop during wildfires to slow the spread of the flames. The company that makes the retardant advertises that their product is a fertilizer, and last year we noticed a disproportionate growth of milk thistle and Italian thistle in the retardant drop zones. Erin decided to investigate this for her senior thesis project. She sprayed the recommended application of Phos-chek on the plots in January and now, a three months later, the results are dramatic. The plots with retardant are much darker green, with much thicker vegetation, than the adjacent control plots. One of her plots contained thistles, and the retardant plot had huge robust thistles as compared with spindly pale thistles in the unsprayed plot.

Reserve Steward Rohana Mayer and Big Creek resident Rose Smiley just finished collecting and analyzing water samples from south coast creeks, including 4 places along Big Creek and Devil's Creek. The results showed some of the lingering effects of wildfire on water quality. When Rohana analyzed the samples for "fecal coliform" bacteria, she found 5-10 times more in Big Creek, Vicente Creek, Limekiln Creek and Willow Creek. The first three creeks drain watersheds, which burned in the 1999 "Kirk" fire, and the Willow Creek drainage burned last summer. Thus, even after 1-½ years, and even though the water in Big Creek is very clear, the fire is having noticeable effects on water quality.

Other notes: The recent cold weather has been hard on some of the native animals. I have seen a couple of shrews lying dead on the roads. They probably starved to death because of the lack of insects to eat...The wildflowers are in full bloom up in the highlands parts of the reserve, with stands of lupines lining the roads and covering the slopes...The creek is fairly low this spring, and never flooded this year. (4-24-01)

 

July 2001

In April a family from the White Mountain Research Station visited us and brought their bat survey equipment. Joseph Szewczak is an engineer-biologist who has developed equipment for listening to the sounds of flying bats, and using the sounds to identify them. If your goal is to find out what bats are present in an area, this technique is a great improvement over the traditional method of catching bats in a mist net, handling them and releasing them. The instrument Joe brought makes a one-second recording which you can play back at 1/10 speed, making the ultrasonic chirps audible. You then plug the recording into a portable computer which analyzes the chirps to produce a sonogram - a graph with pitch on the vertical axis, time on the horizontal, and loudness (volume) as a color intensity. The shape, position and color of the sonogram can be used to identify the species.

Through experience, Joe and other researchers have found that the most reliable way to identify a bat by sound is to record the chirps they make while flying and searching for obstacles or prey. Bats can "hear" their surroundings by listening to the echoes of their chirps, much the same way that a human can see on a dark night by shining a flashlight. Joe is making a database of chirps of bats for California, which others can then use to identify bats at their sites. What Joe and his family did at Big Creek was to set up a mist net and catch a few bats. They identified the bat in hand, and then super-glued an elastic string to the fur (not the skin) of their back. They stretched fishing line horizontally between two poles to make a "run", and clipped the end of the elastic string to the run so the bat could fly up and down the string. Joe could then stand at one end of the run and record the sound of the bat flying toward him.

The most common bat we found was the little brown bat known as Myotis, but there are several species, which can be difficult to distinguish. Joe wanted several recordings from Big Creek. One time we were playing back the little brown bat's chirps and we heard a longer, drawn-out tone like the sound of a sonar ping made by a submarine. Joe said "that's a hoary bat" and we analyzed its sonogram. Instead of a reverse accent mark, which is what the Myotis' chirps look like, the hoary bats sonogram looked like a straight "underline" flat, horizontal and low pitched.

Other notes: the barn swallows returned from their migrations on May 3, and moved into their nests under the eaves of the cabins. Reserve steward Feynner Arias watched a California Thrasher chasing down a mouse, killing it, and eating it. Thrashers have long, curved bills but we never expected them to be used in that way! (6-14-01)

 

August 2001

I just read a wonderful student thesis project done here at the reserve. Erin Avery, an undergraduate researcher from UC Santa Cruz, tested the effects of Phos-Chek fire retardant on plant growth. This is the orange retardant often used to fight wild fires in Big Sur. During the Kirk fire it was used to reinforce fire lines and protect structures. Erin's hypothesis was that, in grasslands, the fertilizing effect of the retardant would alter plant growth in such a way as to encourage the growth of exotics at the expense of natives. She tested this by marking square plots and spraying appropriate amounts of Phos-Chek on the odd-numbered squares, leaving the even-numbered squares as controls. When she compared results she found that the retardant greatly increased nitrate and ammonium levels in the soil, and that exotic annual grasses grew much larger in those plots. By contrast the control (unsprayed) plots had more species, more natives, and more short-statured forbs (wildflowers) plants which were crowded out by the exotics in the treated plots. I will post her project write-up on our web site at www.redshift.com/~bigcreek .

Big Creek is running at low levels, as is typical for late summer (1.46' on our staff gauge near my house). After the wet year of 1998 it read 1.66, in '99 1.47 and in 2000, 1.51. These readings are much higher than in the early 90's following the drought of 1988-92 (for example in 1994 the gauge read 1.14 in late summer). The reason: in 2001 springs are still flowing even though we have had no substantial rain since March, while in 1994 many springs had dried up or had reduced flow as a consequence of the drought. The creek also has mats of dark green algae, something that was prevalent last year, but rare or absent prior to the 1999 Kirk wildfire. Although it looks clean, there is still a substantial amount of sediment in the water, deriving from increased erosion after the fire. This sediment seems to be providing a nutrient base for the algae.

Our education coordinator Kim Smiley recently noticed something interesting and difficult to explain. When she looked for stream insects with her students on August 6, rocks on the bottom of the Devil's fork of Big Creek were cemented together by calcium carbonate. This often happens in late summer and fall. What was surprising was that on August 22 the calcium carbonate had significantly softened, making it possible to pick up and examine rocks which were firmly cemented two weeks before! The only change she could see during this period was that tube-building caddisflies had proliferated and tunneled through the deposits, perhaps softening it as well. (8-24-01)

 

September 2001

UC Santa Cruz researcher Carrie Pomeroy and I just finished analyzing the catch data from the 2000-2001 Big Sur skiff fishing survey. This is the tenth year in a row that we have measured fish caught along the coast (from Pfieffer Point to Lopez Point). Since near shore fishing was light during and before 1991, data from the early years tell us what conditions were like before fishing intensity increased during the mid-90's. The analysis shows that most species don't show any change in the length of the average fish. These include lingcod, cabezon, blue rockfish, kelp greenling, yellowtail rockfish, vermilion rockfish, and kelp rockfish. No species has shown a significant increase in length, but a few have declining average lengths. These include the grass rockfish, the black and yellow rockfish, and the gopher rockfish, which have been declining in the last 2-3 years. Interestingly, all three species are targeted by the live fish market and bring high prices. However, the average length of the cabezon, another species targeted by this market, has remained steady at about 39 cm. One possibly alarming trend is that the copper and the olive rockfish lengths have declined considerably in just the past year. However, the sample sizes are not very large and the results may be a statistical fluke.

Another way that we analyze the data is to plot a "condition" index for each species that tells you how "fat" the fish are for their length. Last year (2000-2001) was "fat" to "intermediate" for all species, 5-10% fatter than during the warm water "El Nino" years of 1994-95 and 1997-98. However, the two shallow-water bottom dwelling species, gopher and black and yellow rockfish, both had their fattest year on record last fall.

The state legislature and the Department of Fish and game has recently proposed that new marine reserves be established along the Big Sur Coast, in addition to the Big Creek Marine Reserve. Their location is still being determined. My experience here at Big Creek is that commercial skiff fishers can be of great help in gathering data and policing marine reserves. I hope they can find a role in the development of the proposed Big Sur reserves.

Other notes: the ridges are extremely dry but the recent fog has humidified the coastal slope and lots of plants are sprouting. Wildlife was coming down to the coast to be in the humid zone, but acorns just started falling up on the ridges, which might draw some species back up. Please send, phone, or email your road kill observations (John Smiley, Big Creek, Big Sur 93920…831-667-2543…jsmiley@cats.ucsc.edu), as we are trying to wrap up our survey for 2000-2001. The info we need is: species killed, exact location, date, time and your name and contact info. John Smiley (9-24-01)

 

December 2001


Mary Yoklavich of the National Marine Fisheries Service recently gave me a map of the ocean bottom right in front of Big Creek. Although unfinished, it shows the land surface from 3000 feet elevation on land right down to 3000 feet under the ocean. The most dramatic thing on the map is the continental shelf. The top of the shelf (we would call it a bluff on land) is about 300 feet deep at the edge, running in a very straight line from upper left to lower center. It probably follows the line of the active San Gregorio-Hosgri fault. Above is a relatively flat zone reaching east about a mile to the rocky shoreline, with boulders and pinnacles in some areas, and flat sandy or muddy bottom in others. Some of the flat bottom has ripples in certain areas. As you drop off the shelf the slope is very steep (almost a cliff), comparable to the slopes overhanging the ocean from above. Even though the shelf runs in a very straight line, numerous depressions (on land we might call them gullies or gulches) run down face of the slope. These gather at the bottom into underwater channels, which appear to run off to the west, gathering into deep canyons. Between the canyons soft sediment appears to have built up into rounded ridges and promontories. The largest such promontory ridge lies west of square black rock, and divides the "canyons" which correspond to Rat Creek and Big Creek, respectively. The top of the ridge begins at about 900 feet below the cliff, and runs five miles offshore at about 2500 feet of depth. The canyons are about 600 feet deep in relation to the surrounding soft-sediment ridges and the heads of the canyons start about 1500 feet below the continental shelf "cliff." It should be no surprise that our underwater geography is as dramatic as on land, but learning the details is exciting.

Mary has completed a fish survey in the upper portions of the continental shelf using the tiny Delta submarine, and has found a great many species of rockfish and other kinds of fish. The steep headwalls of the gullies and canyons seem to harbor the richest, most diverse fish assemblages, perhaps twice as many species as in the kelp forest. Her study is looking at deep-water habitats in a uniquely comprehensive way, involving mapping, quantitative surveys, and bottom surveys. This week she and several coworkers are making a detailed map of part of this area using a new laser probe instrument, which can see items as small as individual fish. Yesterday they hired a commercial fishing trawler to fish on the ocean bottom just south of the reserve. Today they are imaging the track of the net to look for disturbances created by its passage. This kind of information is not available anywhere else, and represents a large investment of time and funding. Only the uppermost reaches of the deep-water zone is protected within the Big Creek Marine Reserve. However, we are proposing that the marine reserve be extended offshore to the three mile limit, and south to Gamboa Point, which would extend the area closed to fishing and protect the area for baseline studies of fisheries and potential environmental change.

Other notes: Thanks to all who contributed to the Big Sur road kill survey. I will soon see the tabulated results and report on what we have found out; however, please keep submitting road kill information. I suspect it will take several years to get a good picture of the "impacts" of the highway. (11-17-01)

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