back to Nature Notes table of contents
back to Big Creek home page\
February 2000 July 2000 August 2000 September 2000 October 2000 November 2000
February 2000 Tanoak and
Coast Live Oak have been browning off and quickly dying in areas
of the Big Sur Valley during the past year. Bill Chaney, an entomologist
from Monterey County Cooperative Extension, has been working on
this problem along with other investigators in Cooperative Extension
and the University of California. He gave a presentation on their
findings at the last meeting of the Big Sur Multi-agency Advisory
Council on January 7, 2000.
According to Mr. Chaney, the die-off was first noticed in Marin County in 1995. When trees turn brown and die quickly with no visible cause, this usually indicates some kind of root disease, often fungal or bacterial in origin. However, in Marin the dead trees invariably had large numbers of bark beetles (western oak bark beetles as well as two species of ambrosia beetles) suggesting that these insects may be involved in the disease. He told us that sometimes bark beetles are secondary, attacking and killing trees that have already been weakened by some other agent such as drought or disease. At other times they become so numerous they can "gang up" on healthy trees and kill them. Apparently the disease has moved south and is now affecting our trees here in Big Sur. However, some trees in Big Sur seem to have died without signs of severe beetle attack, which suggest that the beetles may play a secondary role in the disease. Mr. Chaney is preparing an informational brochure about the disease in Big Sur as soon as he gets enough information.
In December, we left a bobcat carcass near the road just up the canyon, under some redwood snags. Any other time of the year, vultures would be attracted, and would sit on the snags, watching and feeding. Perhaps because of the cold weather, no vultures appeared. After four days a large animal came and ate most of the cat, leaving only a jawbone. I suspected a mountain lion, since other scavengers would probably have carried the entire body away. The other day we left the carcass of a road-killed Mountain Lion in the same place. This carcass probably weighed 80 pounds. A few vultures came around, but could not feed. However, after 6 days a mountain lion came and carried this carcass away. The lion dragged the body down the road, carried it across the creek on our footbridge, and dragged it up the trail a short distance to a place under the redwoods. It ate most of the meat, biting off fist-sized chunks. It ate the meat off the larger ribs, and ate the smaller ribs along with the meat. I have not read that Mountain Lions were such scavengers, but our experience at Big Creek shows that they scavenge carcasses of bobcats, deer and even other lions as long as the meat is fresh.
This is the time of year when our native bunchgrasses are most easily seen. They have sprouted green foliage after the fall rains, but the large annual grasses have not grown up to cover them. The bunch grasses burned in the fire zone have sprouted and seem to be doing quite well. The dry, sunny weather of December and early January seems to have given them a good head start in growth. Unfortunately, the rains were enough to get the milk thistle seedlings to germinate in the bulldozer cut up on Dolan Ridge. Millions of thistles coat the ground where the soil was disturbed.
A note for your calendar: we are planning our 10th annual "Neighbors' Day" open house for the first Saturday in April, April 1. Bring your hiking shoes, a picnic lunch, and come see the reserve on April Fools' Day! You will be able to get a good look at the burned areas of the reserve. (1-8-00)
July 2000.We just completed our 11th annual butterfly count here on the reserve. It was a clear, warm day, ideal for determining just how many and what kinds of butterflies there are in the reserve. This is of particular interest since the fire burned ¾ of the reserve last fall, and might be expected to reduce the numbers of butterflies. This could happen because fire can kill eggs and over-wintering larvae, or because fire reduces the amount of host plant, upon which butterflies depend for food and shelter. What we found was that there were indeed fewer butterflies (about 60% of normal), but that the number of species was normal. Fire effects were most evident at French Camp, where the burn was more severe. There, we saw about 20% of the number of butterflies seen in previous years, and perhaps 2/3 of the number of species. Down in the canyon bottom (where the fire did not burn) we saw normal abundance and diversity of butterflies. Overall, we saw 38 species, which ties previous records and indicates full diversity in spite of reduced numbers of individuals. This is probably a direct result of (1) a reduction in the amount of host plant upon which each species of butterfly depends, and (2) the presence of unburned patches which supported a full diversity of plants and butterflies.
In late May researcher Andrea Henke showed me a spotted owl nest, and I have gone back to check on the nestlings twice since then. There are two huge chicks covered with white down about 2" thick, about the same size as the parents. They have huge black eyes, which, I was told, distinguishes them from yellow-eyed great horned owls. The chicks perch on redwood branches 70' off the ground, and move about from night to night. By June 11 they had juvenile flight feathers and must be able to climb and perhaps flutter from branch to branch, since they moved over 100' feet from the nest tree. An adult, which I presume is the mother, is always nearby, and pretends to sleep as I crawl around on the ground underneath the tree. The chicks make no pretense of sleeping and are very curious about being watched, stretching their necks and staring. Andrea is studying the genetics of spotted owls for her master's thesis at San Jose State University, and plans to collect feathers from owls up and down the coast. She has found 19 owl nests or roosts in Big Sur to date, and has more territory to survey.
Other notes: The fire retardant sprayed by the fire fighters last fall has fertilized enormous crops of thistles along Dolan Ridge and Highlands Ridge in the reserve. While this is good year for thistles in general, the size and density of the thistle patches are 2-5 times as great in the retardant drop zones. Along with myself and our new steward Rohana Mayer, reserve steward Feynner Arias spent several days chopping and weed-eating these patches to prevent them from setting seed. We also chopped thistles along Dolan Ridge fire line. The goal was to minimize the impact of fire-suppression activities on thistle seed-set. (6/11/00)
We have "red sky weather" today - fires are burning above Pacific Valley and sending smoke north to cover the sun. It seems as though the fires burn every summer lately.
A pair of gull chicks hatched and fledged last month, using the Black Oystercatcher nest on the Cove Rock at the mouth of Big Creek. The Oystercatchers abandoned their usual nest ledge after the Big Creek Bridge Reconstruction Project started last April 1998. They did not return to nest in 1999 or 2000. However, the bridge project was completed last June, in time for a mother gull to raise a brood. Apparently it is a desirable place to nest. It will be interesting to see if the Oystercatchers re-occupy the nest next May or if they have permanently abandoned the site. Oystercatchers are present and can often be found mixed with the gulls on Big Creek beach.
This year was a good one for harbor seal reproduction. I counted about 64 pups in early June. Last year I counted 53, so this is the second good year in a row. In 1997 and 1998 I saw only 20 and 14 pups, respectively.
Big Creek has an unusual amount of algae growing on rocks this year. There are large clumps of dark brown bag-shaped algae and some pale orange jelly-like algae in some places. I believe this is a consequence of the fire last fall, providing dirty water and extra nutrients for algal growth. Now that the water level has dropped I can now see where the creek bottom has a lot of new sediment ranging from sand to beds of 1" sized gravel. This should be good news for steelhead spawning, since they like to lay their eggs in gravel beds. We did our annual fish count this July and found lots of steelhead trout in the creek. Apparently the muddy water last fall and winter had no adverse effects on fish populations. Reserve steward Rohana Mayer predicted this result since her water testing revealed that even the muddiest water had large quantities of oxygen last fall and winter.
I have been thinking about the wire mesh drapery that CalTrans has installed above "rain rocks" just north of Limekiln Creek. While I don't approve of its appearance, the wire mesh seems to be effective so far, catching smaller rocks and preventing them from landing on the road below. However, the drapery creates over an acre of an entirely new type of habitat that does not exist in nature: wire mesh lying against a rock face. Some people I have spoken with believe that the drapery will not adversely affect swallow nesting, bat roosting, or raptor perching on the cliff faces. I suspect that there may be effects, however, including long term effects. For example, the drapery allows access to the cliff face by animals such as rodents, weasels and shrews. While they may be slow to colonize this habitat they may do so eventually. I suggest that CalTrans survey the biological diversity of the areas over time to see if such changes occur. (7/24/00)
Maple trees are beginning to drop their leaves in the creek, the days are beginning to get shorter, and it seems like summer is ending. The autumn leaf fall is an important time of year for plants and animals that live in the creek. The creek is low and steady so that delicate organisms can thrive, and the falling leaves rot and provide food. The water is even a tiny bit warmer than the rest of the year, although a pristine stream like Big Creek, running through wooded, shady canyons, is always cold.
Researcher Andrea Henke discovered another nest of Spotted Owls, this time right in Boronda Camp on the north side of the reserve. This breeding pair of owls is only about a mile from the first pair which I wrote about in the July Roundup. This shows how close together Spotted Owls can live, and how many our mountains and forests might support (and how dangerous it is to be a mouse or wood rat around here).
The fire retardant sprayed along fire lines in the reserve is indeed a type of fertilizer. We first noticed this by observing (and later chopping) the enormous growth of thistles where the retardant was used. Called "Phos-chek," the retardant is made from ammonium phosphate and, to quote the manufacturer' s web page "provides a readily available form of nitrogen important for plant fertilization."
I just read in the pages of Science magazine about the "sudden oak death" disease that has killed Tanoaks in Big Sur recently. Researchers from UC Davis apparently found the disease-causing organism to be a new type of Phytophthora, a genus of fungus that causes root rot. This fungus caused the Irish potato famine, and currently the disease is killing trees in parks in Tasmania as well as affecting crops in different parts of the world. The article says that fungicides (poisons that kill fungi) can save individual trees. (8-24-00)
Last week I hiked up Dolan Ridge nearly to the top, to see the burned area and check recovery of the vegetation along last years' fire line. I found nearly a complete canopy of vegetation almost everywhere I looked, including along the fire line itself. This is good news for the prevention of erosion. The stands of chemise and adjacent fire lines are thick with dried wildflowers, so many that the small bell-shaped flowers have fallen into drifts 2-6" deep on the ground. I think they are "whispering bells" and "fiesta flowers". Last spring these flowers covered the slopes, covering them white and blue.
Some of the fire lines were overgrown with what looked like Italian thistle, and often were deeply covered in dried annual grasses. In some areas the burned area was dried annual grassland, dotted with purple-flowered vinegar weed, and the adjacent fire line was indistinguishable (I have a photo of this on the Big Creek web site). In many areas where the fire line went through zones of coastal scrub the fire line was dotted with similar species, including spine flower, black sage, and golden bush. Just above Eagle Rock the burned area was choked with Phacelia plants, so many that you had to wade, hoping you wouldn't put your foot in a hole. I also checked the water bars, which seem to be in good shape, and I predict the fire lines are going to soon recover to the pre-existing vegetation in most cases (unless we have torrential rains this winter). The only disturbing thing I saw was the potential spread of Italian thistle along some stretches of the fire line.
We have observed four road-killed deer this month along the highway just south of the bridge. The deer are down low this month, perhaps crowding into the unburned coastal slope habitats and eating the nice crop of fall flowers (such as the fuschia flowers). Our neighbor Bob Milton has also found a spot where the deer go down to the ocean to lick salt from small splash pools, so the taste for salt may be bringing them down to cross the highway. The road kills are tragic but I needed to get a photo for presentation at a Caltrans planning workshop and I thought, "what are the chances I can just walk out and take a picture of a road kill without searching up and down the highway." I walked about 200 feet from my gate and there was gory scene in which a vehicle travelling at a very high speed had hit a 50-pound fawn.
The harbor seals have done their annual disappearing trick again this year. I checked the haul-out beaches and rocks, and did not see any. I did see a couple of seals in the water, swimming. Although the water in Big Creek has dropped to low levels and seems clean enough to drink (I drink it, anyway) it is not as clean and pure as it was before the fire last fall. I guess it will take another winter before it truly "cleans up". However, our water quality studies show the same bacterial counts as the pre-fire counts, so that aspect of water quality seems to have returned to normal. In fact all the water quality measurements show a return to normal except the visual inspection of the water. (9-23-00)
Last Labor Day marked the beginning of our annual kelp fishing survey. The survey is a cooperative effort between the reserve and a group of commercial fishers who use small skiffs to catch rockfish along the Big Sur coast. The fishers have gathered data on fish sizes and species caught since 1991. One goal of the survey is to monitor sizes for each species and detect potential over-fishing when the length of the average fish begins to decline. Between 1991 and 1997 the survey supported the notion that large fish were still present in Big Sur habitats, for all species caught in large numbers by the fishers. In 1998 a couple of species seemed be a bit smaller than in previous years, but the amount was small enough to have been a "random" fluctuation. Last fall (1999) the decline continued for two species, the Black and Yellow Rockfish and the Grass Rockfish, showing that these two species are probably being over fished, even in Big Sur. This is no coincidence, since these two species are primary targets for the live fish market and earn several dollars per pound when brought to market alive. Interestingly the Cabezon, another species targeted for the live fish market, did not show a decline. Neither did several other species of rockfish.
The survey also reveals "how fat or skinny are the fish," for each species in any given year. The data show that 1995, 1998 and 1999 were "fat " years for species which feed on swimming or drifting prey, such as Blue Rockfish, Vermilion Rockfish, Olive Rockfish, etc. 1997 was a "lean" year, as was 1994. (The scale was broken in 1996, so we have no weight data from that year). 1997 (the data actually run from Sept 1997 to March 1998) was a strong warm water "El Nino" year, as was 1994. Interestingly, the data do not reveal any annual change for Gopher and Black and Yellow Rockfish, two species of bottom-feeding fish in the study. Perhaps their diet is buffered against annual fluctuations caused by "El Nino" warm water events. The kelp fish survey is a neat example of community collaboration in action. It takes only a few days each year for the survey coordinator (me), and a few minutes each day on the part of the fishers, to create a self-sustaining, long-term window on an important natural resource. The longer we sustain the survey the more valuable it will be. You can see the data graphs if you look up http://www.redshift.com/~bigcreek on the internet.
|Big Sur Cabezon. The average size for this species has not declined over the past 4 years, at least for the fish in our survey (August 2000)|
Other notes: It's time for fall colors in the reserve. Maple leaves blanket the canyon bottom, and a few still hang on the trees, orange, yellow and brown. We had strong winds yesterday and I wondered if we would see a fall of redwood seeds, coloring the creek red as happened in 1996. Walking up the trail today I saw no redwood seed at all. Looking up I saw redwoods heavy with a big cone crop: I guess they were just not ready to open and drop their seeds....We had a 1-2" rain in September, including some brief, intense downpours, and the creek rose about 2". This was enough to dirty the water and create high bacteria counts. My impression is that the water was exceptionally dirty as a consequence of the wildfires last fall, as I have observed similar rains in prior years which did not results in darkly colored, dirty water.
John Smiley (10-23-00)
back to Nature Notes table of contents
back to Big Creek home page