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Spring semester classes started this week, and last Saturday’s volunteer day was devoted to clearing overgrown brush and cleaning up around the outdoor classroom, which will be heavily used this semester.

BFS Director Marty Meyer, Ronnie Hollett (Citrus College), and Prof. Dick Haskell (HMC) attack the overgrown vegetation. Nancy Hamlett.

BFS Director Marty Meyer, Ronnie Hollet (Citrus College), and Prof. Dick Haskell (HMC) attack overgrown shrubbery along the side of the classroom. ©Nancy Hamlett.

 

Prof. Dick Haskell (HMC) trims trees away from the classroom roof. Nancy Hamlett,

Prof. Dick Haskell (HMC) trims trees away from the classroom roof. ©Nancy Hamlett,

The results were quite satisfying, as you can see in these ‘before’ and ‘after’ photgraphs:

Before and after: The path on the west side of the classroom. Nancy Hamlett.

Before and after: The path on the west side of the classroom. ©Nancy Hamlett.

 

Before and after: Path on the east side of the classroom. Nancy Hamlett.

Before and after: Path on the east side of the classroom. ©Nancy Hamlett.

 

Before and after: the north side of the classroom.

Before and after: the north side of the classroom. ©Nancy Hamlett.

 

Before and after: Path on east side of the classroom. Nancy Hamlett.

Before and after: Path on east side of the classroom. ©Nancy Hamlett.

Have a good semester everyone and enjoy the spiffed-up classroom!

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Ho, ho, the mistletoe
hung where you can see…

Songs about mistletoe wafting through stores during the holiday shopping season got me wondering about mistletoe at the BFS. This time of year, when the leaves are off the Western Sycamores, you can certainly see that many of the trees are hung with mistletoe.

Clumps of Big Leaf Mistletoe (Phoradendron serotinum ssp. macrophyllum) in a Western Sycamore (Platanus racemosa) at the BFS. Nancy Hamlett.

Clumps of Big Leaf Mistletoe (Phoradendron serotinum ssp. macrophyllum) in a Western Sycamore (Platanus racemosa) at the BFS. ©Nancy Hamlett.

But aside from decorating doorways for winter celebrations, what role does mistletoe play in the BFS ecosystem?

The mistletoe at the BFS is Phoradendron serotinum ssp. macrophyllum, known as Big Leaf Mistletoe or Colorado Desert Mistletoe. Big Leaf Mistletoe is hemiparasitic – it contains chlorophyll and fixes some carbon by photosynthesis, but it also takes some carbon from its host tree as well as all its nitrogen and water.

Mistletoe’s white berries are eaten by birds, which excrete the seeds. When mistletoe seeds have sticky substance that allow them to adhere if they land on a twig. Then the attached seed begins to develop chlorophyll and cotyledons on the top, and an embryonic root (the radicle) grows from the bottom of the seed, curves away from the light (negative phototropism), and pushes into the twig, where after a excreting an exquisitely tuned set of chemical signals, it develops a specialized structure (haustorium) within the twig that allows the mistletoe to take water and nutrients directly from the tree’s xylem and phloem.

Leaves and berries of Big Leaf Mistletoe (Phoradendron serotinum ssp. macrophyllum). Nancy Hamlett.

Leaves and berries of Big Leaf Mistletoe (Phoradendron serotinum ssp. macrophyllum). ©Nancy Hamlett.

Mistletoe can harm trees by stealing water and nutrients, especially during periods of drought, when mistletoe releases large amounts of water (which all comes from the tree host) to the air. But mistletoe berries are also an important food for certain birds, such as Phainopeplas, Cedar Waxwings, and Western Bluebirds, so what is its overall effect?

Prof. David Watson and Adjunct Matthew Herring of the Institute for Land, Water and Society at Australia’s Charles Stuart University recently published a paper that addressed just this question. Using ‘cherry pickers’ and a crew of volunteers, Watson and Herring removed all the mistletoe (41 tons!) from seventeen 3 to 60-acre isolated woodland remnants. For comparison, they used eleven control sites, from which they removed an equivalent amount of foliage – but no mistletoe, and twelve sites that naturally lacked mistletoe.

After three years they surveyed birds on all the sites and found that the sites from which mistletoe had been removed had lost an average of 34.8 per cent of their woodland-dependent resident birds, 26.5 per cent of woodland-dependent bird species, and 20.9 per cent of their total species richness. In contrast, control sites showed moderate increases, while mistletoe-free sites showed no significant changes.

But perhaps the most surprising finding was that most of the decrease in bird species was not due to loss of species that forage on mistletoe, but of birds that eat insects, especially birds that eat insects on the forest floor. The authors attribute this effect to the lack of mistletoe litter, which is especially nutrient-rich. As Watson explains in an NPR interview, while regular trees “pull out the good stuff from their leaves before allowing them to fall”, mistletoes, “because they’re moochers,… don’t really care about conserving their resources – they can just suck out more” and “just drop their leaves with all the vitamins inside.” This rich litter can support more insects and thus more insect-eating birds, and possibly more reptiles and mammals, too.

Although the mistletoe species studied in Australia were different from the one found at the BFS, Daniel Nickrent, a professor of plant biology at Southern Illinois University, is quoted in the NPR interview as being convinced that the Phoradendron mistletoes play a similar role in North American forests.

Perhaps an enterprising student would like to compare arthropod diversity under trees at the BFS with and without mistletoe?

References and more information:

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BFS Director Marty Meyer is initiating an arthropod monitoring program at the BFS, and this past Saturday, volunteers helped get the program underway by installing permanent sleeves for pitfall traps in the non-native grasslands in the East Field and in the area of recovering coastal sage scrub. The data collected on the abundance and diversity of ground-dwelling arthropods (such as beetles, ants, pill bugs, and scorpions) in different habitats at the BFS as well as in areas outside the BFS will help us understand which arthropods are endemic to coastal sage scrub and inform conservation and restoration.

The ground-dwelling arthropods will be collected in pitfall traps made out of large test tubes. To facilitate repeated collecting the same locations, permanent sleeves of PVC pipe are placed in the ground so their tops are level with the soil surface. When not in use, the sleeves are capped to prevent anything from falling in. When a trap is deployed, the cap is removed, a test tube is fitted snugly into the sleeve, and sleeve and test tube are covered with a cap that excludes small rodents and reptiles but allows the arthropods to enter the trap. You can read more about the traps here.

Pitfall trap sleeves awaiting installation. ©Nancy Hamlett.

The first step in deploying the traps is obviously to install the sleeves. In each habitat, 8 sites with three sampling locations in each had already been selected. One team of volunteers installed pitfall trap sleeves in the grasslands…

Prof. Paul Stapp (Cal State Fullerton), Elise Boyd (Pomona ’16), and Ben Stapp at work in the grasslands. ©Nancy Hamlett.

…while a second team installed the sleeves in recovering coastal sage scrub.

Prof. Dick Haskell (HMC), Michael Lertvilai (HMC ’16), and BFS Director Marty Meyer working in the recovering coastal sage scrub. ©Nancy Hamlett.

Making holes in the ground at the BFS can be a bit tricky. Because the BFS lies on an alluvial fan, the soil is full of pebbles and rocks wash down from the San Gabriel Mountains. Several tools were used to make holes for the sleeves, including narrow drain spades…

Elise Boyd (Pomona ’16) digs a hole with drain spade. ©Nancy Hamlett.

…and heavy San Angelo bars. Even so, we occasionally had to relocate the holes to avoid large boulders.

Prof. Paul Stapp (Cal State Fullerton) digs a hole with a San Angelo bar. ©Nancy Hamlett.

At the end of the workday, all 48 sleeves were installed in place, just waiting for the trapping to begin.

A completed installation of a pitfall trap sleeve. ©Nancy Hamlett.

As always, there were interesting things to see while we were working. The grasslands right now have a lot of grasshoppers, like this one:

Ben Stapp holds a female Devastating Grasshopper (Melanoplus devastator) found in the East Field. ©Nancy Hamlett.

We also found a soccer ball covered with teethmarks. Soccer-playing coyotes? Now that’s a sight I’d like to see!

Do coyotes play soccer? A soccer ball covered with teeth marks found in the East Field. ©Nancy Hamlett.

This was the last volunteer workday before the winter holiday. Thanks to everyone who’s participated! Workdays will resume on January 19. Please check the volunteer schedule for updates.

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A new update if the BFS Reptile and Amphibian List is now available. The changes to the list since the last update are minimal. Here’s what’s new:

  • Links to the USGS Western Ecological Research Center’s Field Guide to the Reptiles and Amphibians of Coastal Southern California have been repaired.
  • Photos of reptiles and amphibians have been migrated to the BFS Photo Database, and a number of new photos have been added. Check them out!

    One of the new photos — a San Bernardino Ring-necked Snake (Diadophis punctatus modestus). ©Stanleigh Jones.

  • A few names have changed to conform to the new edition of standard names published by the Society for the Study of Amphibians and Reptiles (Crother 2012):
    • The common name of Aspidoscelis tigris stejnegeri has been changed from Coast Whiptail to San Diegan Tiger Whiptail
    • The common name of Plestiodon skiltonianus skiltonianus has been changed from Western (Skilton’s) Skink to Skilton’s Skink

      Skilton’s Skink (Plestiodon skiltonianus skiltonianus) at the BFS. ©Jonathan Wright.

    • For Uta stansburiana (Side-blotched Lizard), we now list the subspecies that occurs at the BFS – Uta stansburiana elegans (Western Side-blotched Lizard)
    • For Pituophis catenifer (Gophersnake), we now list the subspecies that occurs at the BFS – Pituophis catenifer annectans (San Diego Gophersnake)
    • Lampropeltis getula californiae (California Kingsnake) has been elevated to its own species – Lampropeltis californiae
    • The subspecies designation has been removed from Anaxyrus boreas halophilus (Southern California Toad), so it’s now just listed as Anaxyrus boreas (Western Toad). Recent molecular evidence suggests that Anaxyrus boreas is a complex of species that do not comform to the traditional limits of species and subspecies, and Crother (2012) has consequently dropped the subspecies names.

      A newly metamorphosed Western Toad (Anaxyrus boreas). The toadlet hopped right onto the dime we were using as a scale marker. ©Nancy Hamlett.

If you have any interesting reptiles or amphibian sightings or get any nice photos, please pass them along to the BFS Webmaster.

A Western Pond Turtle (Actinemys marmorata) in pHake Lake. ©Nancy Hamlett.

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BFS student researcher Lauren Dorough, Cal State Fullerton, received a SACNAS Student Research Presentation Award at the SACNAS National Conference, held October 11–14 in Seattle, Washington, for her outstanding research poster, “Effects of Urbanization on Activity and Diversity of Southern California Bats”.

Lauren Dorough with her poster. Credit: Courtesy of Cal State Fullerton.

Urbanization affects many bat species by causing loss of roosting sites and foraging habitat, but it’s unclear what factors allow some bat species to persist in cities and suburban landscapes, while others decline. Because little is known about how Southern California’s 14 bat species are affected by urban development, Lauren monitored bat activity and species richness at the BFS and three other sites in the San Gabriel Valley that vary in microhabitat features and levels of urbanization. To monitor the bat populations, Lauren used an acoustical detector to record bat echolocation calls and then analyzed the recorded calls with special software to identify each bat species.

Lauren deploying her equipment at one of her study sites. Credit: Courtesy of Cal State Fullerton.

You can see her equipment deployed at pHake Lake in this earlier post.

Lauren’s work on how bats are affected by the loss and fragmentation of natural habitats will aid in regional bat conservation efforts, and we congratulate Lauren on her award!


More information:

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ABC Channel 7 news recently featured BFS researchers Prof. Chis Clark (Harvey Mudd Engineering) and his students and their work tracking sharks with autonomous underwater vehicles (AUVs or robots).

During this past summer and fall, the Clark group has been testing their AUVs in pHake Lake. If you happened by the lake at the right time, you may have seen students out in the boats controlling and monitoring the AUVs from a laptop computer…

Chris Gage and Dylan Shinzaki (under cover so he can see the computer screen) testing the AUV in pHake Lake. ©Nancy Hamlett.

…or seen the robots and associated gear at the boat landing:

The AUV and associated gear at the pHake Lake boat landing. ©Nancy Hamlett.

Once the group completed this summer’s testing, they took the AUVs to Catalina Island to track leopard sharks, and ABC Channel 7 News reported on the shark-tracking robots:

Click photo to see the ABC video! (Photo courtesy of Dr. Gwen Goodmanlowe)

According to the Harvey Mudd College News Release:

The new shark tracking technology allows scientists to follow sharks across longer distances and for longer time periods of time, as well as report on the sharks’ environment, providing information about the factors that may influence their migration patterns.

The tracking system uses multiple autonomous underwater vehicles, or AUVs, equipped with sensors designed to receive signals from an acoustic-emitter tag attached to the shark. Based on the tag’s time of arrival and signal strength data, the AUV can estimate and follow the shark’s location. The AUVs, which resemble small torpedoes, are programmed to continuously circle the the shark. The AUVs follow opposite sides of the circular paths to provide opposing sensor vantage points of the shark.

Notably, Gage ’13 wrote code for an acoustic communication-based command and control system that allows the researchers to run and monitor the system from a dock or boat. Successful multi-AUV tracking and following of a leopard shark was accomplished this past summer in Big Fisherman’s Cove, Catalina Island, Calif.


Sources and more information:

This past Saturday BFS Volunteers braved a rainy day to help with something different at the BFS. Instead of clearing trails or removing weeds, they helped with a BFS research project being carried out by Harvey Mudd senior Megan Wheeler.

Megan is comparing carbon storage in the native coastal sage scrub and the east field, which is vegetated mainly by non-native invasive grasses. Any carbon that is stored in soil and vegetation is not being released into the atmosphere to contribute to global warming, so understanding how disturbance (such as displacement of native sage scrub with exotic grasses) affects carbon storage is an important – yet poorly understood – factor in modeling climate change.

Megan Wheeler (bright blue jacket) and volunteers listen as BFS Director Marty Meyer explains the carbon storage research project. ©Nancy Hamlett.

Megan has 24 plots in three habitats – intact coastal sage scrub, grassland, and recovering coastal sage scrub – and 3 subsamples from each of these plots, for a total of 72 samples. In each of these, she is analyzing carbon stored in above-ground biomass, below-ground biomass, and litter – which is where the volunteers came in. The litter from each of the 72 samples needs to be sorted into wood, grasses, broad non-grass leaves, and small fragments of Artemisia and other material. This is clearly a task that could use a lot of hands!

Caroline Nielsen (HMC ’16) sorts litter from her tray. All that came from just 0.1 m2! ©Nancy Hamlett.

The litter samples were dumped into trays, then sorted into paper bags – one for each category of litter.

Bags and an empty tray await litter sorting while Michael Lertvilai (HMC ’16), Elliott Cox, and Tim Cox sort their bags of litter. ©Nancy Hamlett.

We got an excellent demonstration of the patchiness of natural habitats. One of Tim Cox’s samples was full of our old friends, Maltese Star Thistles, plus a generous supply of rabbit poop.

Tim Cox contemplates his trayful of Maltese Star Thistles. ©Nancy Hamlett.

Caroline Nielsen (HMC ’16) sorts, while Thendral Govindaraj (HMC ’16) gets advice from Megan Wheeler (HMC ’13). Three sorted bags from sample F-R-4-L-3 are in the foreground. ©Nancy Hamlett.

This was the perfect activity for a rainy day!

Raindrops on Toyon berries. ©Nancy Hamlett.

We hope that BFS volunteers can help with more BFS research projects in the future. For a schedule of upcoming volunteer activities, please check our volunteer page.

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BFS Director Gene Fowler with the newly created sign for the BFS entry, 30 September 2001. ©Nancy Hamlett.

It is with great sadness that the BFS notes the passing of former BFS Director, Dr. Gene Fowler. Dr. Fowler died November 1, 2012, at Pomona Valley Hospital Medical Center following a serious illness.

Dr. Fowler was Associate Professor of Biology at Pomona College and served as Co-Director or Director of the BFS from 1995–2001. He completed his undergraduate work at California State University, Sacramento, receiving a B.S. with honors in Biological Conservation, and he subsequently received an M.S. in Wildland Resource Science from UC Berkeley and a Ph.D. in Zoology from the University of Washington before coming to Pomona in 1993. At Pomona he taught courses in biology and Environmental Analysis, including Conservation Biology, Comparative Endocrinology, and Introduction to Environmental Studies. He was also instrumental in the founding of the Environmental Analysis program and for many years served as faculty advisor for students in the EA environmental biology track.

Dr. Fowler was a staunch supporter and advocate of the field station, and, in addition to serving as Director, he carried out research at the field station, supervising a number of student theses carried out at the BFS.

He is survived by his wife Cynthia Peters and son Zachary; his parents, Murray and Audrey Fowler; and siblings Alan Fowler, Linda Allen, Tricia Craft and Janet Akema, and their families.

There will be a “celebration of life” for Dr. Fowler and the people whose lives he touched on Saturday, November 24, 2012, at 2 p.m., in Little Bridges (Bridges Hall of Music, Pomona College, 150 E. Fourth St., Claremont), with a reception following. In lieu of flowers, the family is asking that donations in Gene’s memory go to either the Claremont Educational Foundation or the California State Parks Foundation.

Condolences may be sent to:

Cynthia Peters
c/o Pomona College Communications
550 N. College Avenue
Claremont, CA 91711

 


 

This past Saturday a team of hard-working volunteers removed two species of invasive trees that were sprouting up in the Foothill Blvd parkway – Ailanthus altissima (Tree-of-Heaven) and Melia azedarach (Chinaberry). Both of these fast-growing Asian Trees resprout from stumps or root fragments, so the volunteers had to dig up the roots.

Prof. Dick Haskell (HMC), Bryan Visser (HMC ’13), Thendral Govindaraj (HMC ’16), Cleo Stannard (HMC ’16), Lee Krusa, Caroline Nielsen (HMC ’16), and Tim Cox digging out Trees-of-Heaven and Chinaberries. ©Nancy Hamlett.

 

Cleo Stannard (HMC ’15) and Tim Cox dig out a Tree-of-Heaven sprouting from a large root, while in the background Sarah Stevens (HMC ’15), Thendral Govindaraj (HMC ’16), and Caroline Nielsen (HMC ’16) dig up more trees. ©Nancy Hamlett.

The volunteers completely removed all the invasive trees from two areas – one to the east of the entry gate…

Before: Trees-of-Heaven sprouting in the parkway east of the entry gate. ©Nancy Hamlett.

After: Trees-of-Heaven removed. ©Nancy Hamlett.

…and one to the west.

Before: Trees-of-Heaven and Chinaberries west of the entry gate. ©Nancy Hamlett.

After: Trees-of-Heaven and Chinaberries removed. ©Nancy Hamlett.

While working in the parkway, the volunteers also trimmed up some of the Coast Live Oaks (Quercus agrifolia) and European Olives (Olea europaea) where there was evidence of camping under the tree canopies.

Scott Rayermann (HMC ’13), Maria Morabe (HMC ’13), and Prof. Paul Stapp (Cal State Fullerton) trim low-hanging branches from a Coast Live Oak. ©Nancy Hamlett.

 

The BFS entrance with the live oak trees trimmed up. ©Nancy Hamlett.

And last, the volunteers picked up trash in the parkway – plastic bags, papers, fast food cups, an old yoga mat, and even a political campaign sign.

Maria Morabe (HMC ’13) and Anne Clark (HMC ’13) pick up trash in the parkway. ©Nancy Hamlett.

Of course, we also noticed some interesting flora and fauna. Ben Stapp found a burl from an olive tree…

An olive burl found while trimming the Olive Trees. ©Nancy Hamlett

…and his dad, Prof. Paul Stapp, uncovered a Jerusalem Cricket (Stenopelmatus sp.) while digging.

A Jerusalem Cricket uncovered during the digging. ©Nancy Hamlett.

Thanks to all the volunteers, who did a terrific job! Everyone is welcome to join us on the first and third Saturdays for most months – you can check the schedule here.

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Two clumps of Chinaberries growing in the Foothill Blvd parkway. (The young trees behind them with lighter green leaves are Trees-of-Heaven). ©Nancy Hamlett.

A new plant invader has been spotted at the BFS – Melia azedarach. This tree is commonly known as Chinaberry, but also has many other common names, including Texas Umbrella Tree, Persian Lilac, White Cedar, Bead-Tree, Cape lilac, Ceylon Cedar, and Pride of India. Several sprouting clumps of M. azedarach growing in the Foothill Blvd parkway with Ailanthus altissima (Tree-of-Heaven), were removed by volunteers last Saturday.

This member of the mahogany family (Meliaceae) is a fast-growing tree (reaching heights of up to 50 ft) that is native to temperate and tropical Asia (China, Japan, India, Sri Lanka, Indonesia, Papua New Guinea), Australia, and the Solomon Islands. It was introduced as an ornamental into Charleston, South Carolina, around 1830 and is now naturalized throughout the southern half of the US.

M. azedarach has large (up to 2 ft long), doubly compound alternate leaves on long petioles. The leaflets are dark green above and lighter green below, with serrate (saw-toothed) margins.

 

A leaf of a Chinaberry, Melia azedarach. ©Nancy Hamlett.

The Chinaberry tree has all the hallmarks of an invasive species. It has few predators outside of its native habitat and requires little water. Its huge numbers of fruits attract birds, who disperse the seeds over large distances, and it also sprouts from stumps and roots (especially if the plants are injured or cut) to form dense thickets that crowd out native vegetation. Its leaf litter changes the soil chemistry – increasing the pH and the nitrogen content, and the leaves and roots release compounds that inhibit the germination and growth of other plant species (allelopathy).

Although M. azedarach primarily colonizes disturbed areas, some invasion of intact habitat has been reported in Texas and Florida. It has not yet been listed as invasive by the California Invasive Plant Council, but it is listed as invasive the National Park Service, the Florida Exotic Pest Plant Council, and Texas Invasive Plant & Pest Council.

We hope we have removed all the Chinaberry trees, but if you spot any at the BFS, please report them to the Director, Wallace Meyer (Wallace.Meyer@Pomona.edu).

More information:

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