Science Magazine and the Guardian
Climate change could increase bumble bees’ extinction risk as temperatures and precipitation begin to exceed
species’ historically observed tolerances. A new study adds to a growing body of evidence for alarming, widespread losses of biodiversity and for rates of global change that now exceed the critical limits of ecosystem resilience.
Read more about this topic here and here, or read the research study here.
Twenty-Year Study Shows How Climate and Habitat Change Impact One Mantid Species
By Paige Embry, Entomology Today
Ask someone what they know about praying mantids and chances are they’ll bring up the female biting the male’s
head off during mating. It happens, albeit only about 17 percent of the time, but those deaths can be a surprisingly
useful tool when studying mantid population changes over time. It’s one of the pieces of information tracked by
Lawrence Hurd, Ph.D., a professor of biology at Washington and Lee University, during a 20-year study
(1999-2018) of Tenodera aridifolia sinensis, the Chinese praying mantid.
The results were published in January in Annals of the Entomological Society of America.
In the last few years, studies finding widespread declines in insect abundance have made headlines. Hurd’s
long-term study uses one insect in one northern Virginia field to show how such declines can happen. Although the study only followed one species, Hurd and coauthorsnote that the findings should apply to other insects and spiders with a similar life cycle.
For this study, Hurd made good use of his resources. He had an insect of unusual size (7-10 centimeters) that beginners (his college ecology lab students) could easily recognize and catch. He also had a nearby field beginning its natural succession, which functioned as a laboratory because the mantids couldn’t easily escape from it. No other suitable fields were close by, and the mantids aren’t very mobile.
Five times between 1999 and 2018, on approximately the same day in September, Hurd sent his students across the
field in a “skirmish line” to collect, mark, and note every possible T. a. sinensis. Hurd writes in an email, “I always
try to base it [the class] on gathering good, usable data instead of just make-work data collection on a question that
has already been answered.”
To assess the reproductive success of the mantids, they went back after the first frost to collect the oothecae (eggs
laid in a gooey substance that hardens into a protective case). They brought the oothecae back to the lab, weighed them, and then returned them to the field. For the oothecae found on the stems of herbaceous plants, that meant “tying [them] on with sewing thread run through the dried foam surrounding the eggs.” Mantids do well in flowery fields with lots of arthropod prey. When succession trends in an area lead to more trees, the population of mantids should shrink. Over the 20 years of this study, two-thirds of the open field area was replaced by trees, and the number of mantids decreased dramatically.
However, succession was not the only factor impacting the mantids—climate change was as well. When a Chinese praying mantid lays her eggs, the sex ratio is even. By the time the mantids reach adulthood, males outnumber females. Once mating begins, the percentage of males starts to fall, prey to the females as well as any other
predators in the field. Eventually, the females become more common. Even though Hurd and the students sampled on essentially the same calendar day (September 12, 13, or 14) each year, they found that the proportion of males to the total population declined from more than 60 percent in 1999 to about 25 percent in 2018, showing that the mantids were further along in their life cycle.
It’s no surprise. For the last 40 years the growing season in northern Virginia has gotten longer and the summers hotter, so the mantids both hatch and reach maturity earlier. This means that some eggs may hatch before frost can put them into diapause, leading to death of the young nymphs and potentially adding to the population losses caused by the successional change.
In 2018, Hurd and his students found only three oothecae. In the fall of 2019, he saw no mantids, and found no oothecae after the first frost.
This study demonstrates the potential double whammy of habitat loss—even a naturally occurring one—and climate change. Hurd writes, “People are becoming worried about having to include insects in the mass extinction episode that many (including me) feel is already underway.” He says when he talks about this, people often respond with, “‘We gotta worry about bugs, too?'”
Unfortunately, as this study illustrates, the answer to that question is “yes.”
Find this article in Entomology Today here.
Find other articles on declines in insects and biodiversity on the Reading Corner page.
World’s fireflies threatened by habitat loss and light pollution, experts warn
Lightning bugs cannot signal to one another to mate if there’s too much light at night.
By Ben Guarino
Feb. 3, 2020 at 12:22 p.m. EST
(shared by Charlene Uhl, Class X)
Nearly 2,000 species of fireflies flit, crawl and sparkle across the planet. Some of these lightning bugs are doing fine. Others are not.
A survey of 49 of the world’s firefly experts, published Monday in the journal BioScience, has identified the most serious threats to the animals. Habitat loss, in almost all of the regions surveyed, is a problem. Other threats include artificial light, which disturbs their mating rituals; pesticides, which can harm the insects or their invertebrate prey; and water pollution, for species that have an aquatic stage.
The report is not a census of the world’s firefly population. But it is “the very first time that we’ve gathered information — this is based on expert opinion — about what the most prominent threats are to the fireflies in different parts of the world,” said study author Sara M. Lewis, a biologist at Tufts University.
“For the last decade or more, people have been anecdotally reporting that they’re not seeing fireflies where they used to,” Lewis said. “Good census data over the past few decades” exists for some species, such as Malaysia’s synchronous fireflies and the common European glowworm, Lewis said. “We know that those populations are, in fact, declining.”
Elsewhere, however, firefly literature remains “kind of obscure,” she said, and the research community is relatively small.
This poll of firefly experts was the “next best thing” to traveling back in time to count firefly populations, said University of Florida entomologist Marc Branham, who was not a member of the research team. He has been told many anecdotes of missing fireflies. And often, he said, they’re believable. Fields once full of flashing insects “are so obvious, in a sort of a sad sense,” when the light vanishes, he said.
“One of the things we’ve kind of taken for granted is that fireflies will always be here,” said naturalist Ben Pfeiffer, founder of the nonprofit Firefly Conservation & Research organization and one of the firefly experts who was surveyed. “And we’ve been terribly wrong about that.”
In 2018, the International Union for Conservation of Nature created the Firefly Specialist Group, co-chaired by Lewis, to determine whether certain firefly species should be listed as threatened or endangered. “That’s something we’ve never seen happen for a firefly species,” Fitchburg State University biologist Christopher Cratsley said. Cratsley was not a member of the study team.
The survey, Lewis said, represents a first step in that process. She cautioned that “we don’t know what the relative importance of these threats to fireflies are. We only know the ranking of what firefly experts believe.”
A contrast in firefly health is evident in the eastern United States. There, Photinus pyralis -- also known as the big dipper firefly, for the dipping J-shape path the beetle makes as it flies — remains a common sight at dusk. “It’s a very weedy species. It’s a habitat generalist,” Lewis said. These fireflies swoop over rural meadows and the streetside gardens of the District. “We’re lucky that we have some fireflies that are probably going to be just fine.”
Due east of the nation’s capital, however, the situation is dire for the Bethany Beach firefly. That insect, which produces bright green double-flashes, lives only in Delaware’s coastal freshwater wetlands. Residential development has imperiled the species, and in May the Center for Biological Diversity and the Xerces Society for Invertebrate Conservation petitioned the Interior Department to add the firefly to the Endangered Species List.
Artificial light at night can confuse the fireflies and glowworms that use bioluminescence for mating rituals. In the United Kingdom, female glowworms climb up to perch at the tips of vegetation and glow to attract males. “A number of different studies have shown that artificial light in a glowworm habitat actually prevents the males from finding the females,” Lewis said.
Background illumination can also mess up the animals’ sense of timing. “I’ve seen fireflies in New York City that begin courting at like 4 in the afternoon in the summertime, which is not the right time,” Lewis said.
In countries such as Japan, Malaysia and the United States — particularly where there are synchronous firefly displays, like the Smoky Mountains — firefly tourism attracts about 200,000 visitors per year, Lewis estimated. Well-meaning tourists may not realize they are endangering the animals they wish to appreciate. “If you have a lot of people who are tromping through the firefly’s habitat, they’re stepping on larvae” or flightless females, she said.
Some places have taken precautions against trampling feet and have developed firefly sanctuaries with elevated footpaths. A recently enlarged firefly preserve in New Canaan, Conn., is the first of its kind in North America, Cratsley said, at least as far as he was aware.
“The land trust was immediately adjacent to a large mansion — a beautiful home,” he said, of his visit in summer 2019. “But you could go from being surrounded by fireflies to a complete dead zone, of nothing, in that manicured lawn.”
The firefly experts encouraged people to join monitoring groups such as Firefly Watch, a citizen-science project run by Mass Audubon that has partnered with Cratsley, Lewis and other researchers.
“If people are willing to spend five or 10 minutes each week out in their backyard figuring out what kind of fireflies they have and then counting their flashes,” Lewis said, “we think we could begin to gather the kind of long-term data that we need to figure out what species are in trouble.”
Where Light Pollution Is Seeping Into the Rural Night Sky (click here)
by Jeff Stehm
We are often caught up in the here and now, or at best, think only in human time scales. But have you ever wondered about what Shenandoah National Park looked like millennia ago or might look like a millennium in the future?
Shenandoah National Park today hosts a rich Appalachian Oak forest consisting of hickory, maple, and tulip poplar, with oak as the dominant tree species. Pine predominates on warmer southwestern faces of the southernmost hillsides. In cooler areas with northeastern aspects, small, dense stands of moisture loving hemlocks exist.
The average annual temperature in the Park is about 46.5°F at Big Meadows (located in the north central area of the Park), and ranged from about 44°F to a little over 50°F over the last 75 years.
Forty-five thousand years ago it was a very different place. North America was in the midst of the last throws of the ice age. Temperatures fluctuated (over centuries) from cold to warm and back again. Litwin et al. (2004) estimated that the mean annual temperatures around Big Meadows varied about 20°F over the 45,000 year period, ranging from about 35°F to 55°F. In today’s climatic terms, these variances in temperature was equivalent to those existing today from latitude 55°N (Northern Newfoundland) to 32°N (Georgia).
Such temperature swings profoundly affected the forests of Shenandoah National Park. The Park experienced temperatures almost 10°F colder to 5°F warmer – enough to shift forest biomes drastically back and forth between cold artic boreal forests and warm Oak-Hickory-Pine and Southern Mixed forests.
Forest biomes shifted back and forth a minimum of 37 times during the last 45,000 years as shown below.
Forest Type Years Ago Climate
Boreal 45,000-37 000 Cold
Northern Hardwoods 36,000-35,000 Warming
Northern Harwood-Spruce 32,000 Cooling
Boreal 28,000 Cold
27,000 Last Glacial Maximum
Northern Hardwoods 26,000 Warming
Boreal 25,000 Cold - Northern Hemisphere Insolation Minimum
Northern Hardwood-Spruce 24,000 Warming
Boreal 22,000 Cold
NE Spruce-Fir 17,000 Cool
15,000-13,000 Warming - Bolling-Allerod Interstadial Warming
Northern Hardwood-Spruce 13,000-12,000 Cooling - Younger Dryas Cold Pulse
Appalachian Oak 10,000-6,000 Warming
Southern Mixed 6,000-4,000 Warming
Appalachian Oak 4,000-present Cooling
Source: Adapted from Litwin et al., 2004.
Climate is continuing to change in Shenandoah National Park. Average temperatures in the SNP are expected to shift upwards any where from 1.7°F to 12.7°F depending on the climate model, assumptions, and baseline years. By the end of the century, temperatures are likely to exceed the upper end of the historical range of the last 45,000 years.
In addition to temperature changes, annual precipitation is expected to increase from 1.5 to 8.5 inches by the end of the century. The future climate at the Park, therefore, is likely to include on average milder winters with fewer frost days, hotter summers, and wetter and cloudier conditions.
As a result of these climate changes, Shenandoah National Park is likely to evolve from an Appalachian Oak biome to a Southern Mixed Pine biome.
This may mean a loss of species such as maple, eastern hemlock, northern red oaks, yellow poplar, beech, and other northern hardwoods, and an increase in hickory, sweet gum, shortleaf and longleaf pine, loblolly pine, various elms, and southern oaks (National Park Service, 2015b).
Appalachian Oak Forests Southeastern Mixed Pine Forests
Source: Wikipedia Source: Wikipedia
But climate changes are occurring faster today than they did 45,000 years ago. Temperature and precipitation changes that occurred in the past over thousands of years are occurring today in less than 100 years. In the short term this is likely to:
For example, native brook trout are a cold-water fish. Park officials have measured warmer stream temperatures in recent years, which could put the brook trout under stress and may ultimately eliminate or greatly reduce their numbers in the Park (Saunders, et al., 2010; Flebbe, et al., 2006; National Park Service, 2017a). Another animal that may become a climate change casualty is the Shenandoah salamander, an endangered species that is found nowhere else on the planet.
About a quarter of bird species and 10 percent of the mammals in the Park will likely shift their ranges into and out of the park as the result of either direct or indirect climate effects (National Park Service, 2019d; Wu, et al., 2018; Burns, et al., 2003). Some mammal species, such as the red squirrel and the southern red-back vole, are particularly sensitive to climatic conditions and may be lost to the Park (Burns, et al., 2003). Species reshuffling, however, may result in a net gain to the Park, as more species move into and colonize the Park than move out.
So when you next consider the Good Ole Days, think longer term, both in terms of the past and the future.
Burns, C. E., Johnston, K. M., & Schmitz, O. J. (2003). Global climate change and mammalian species diversity in U.S. national parks. Proceedings of the National Academy of Sciences, 100(20), 11474–11477. DOI: 10.1073/pnas.1635115100
Flebbe, P. A., Roghair, L. D., & Bruggink, J. L. (2006). Spatial Modeling to Project Southern Appalachian Trout Distribution in a Warmer Climate. Transactions of the American Fisheries Society, 135(5), 1371–1382. DOI:10.1577/T05-217.1
Litwin, R. J., Morgan, B., Eaton, L. S., & Wieczorek, G. (2004). Assessment of Late Pleistocene to recent climate-induced vegetation changes in and near Shenandoah National Park. USGS OFR 2004-1351. DOI: 10.3133/ofr20041351
National Park Service (2019d). Projected Effects of Climate Change on Birds in U.S. National Parks, Briefing Note. Retrieved from https://www.nps.gov/subjects/climatechange/upload/01-NPS_Overall_Project_Brief_508Compliant.pdf
National Park Service. (2017a). Climate Change Impacts at Shenandoah National Park. Retrieved from https://www.nps.gov/shen/learn/nature/climatechange.htm
National Park Service. (2015b). Climate, Trees, Pests, and Weeds: Change, Uncertainty, and Biotic Stressors at Shenandoah National Park. Project Brief.
Saunders, S., Easley, T., & Spencer, T. (2010). Virginia Special Places in Peril: Jamestown, Chincoteague, and Shenandoah Threatened by Climate Disruption. The Rocky Mountain Climate Organization and NRDC. Retrieved from http://www.rockymountainclimate.org/images/VA_SpecialPlaces.pdf
Wu, J.X., et al. (2018). Projected avifaunal response to climate change across the US National Park System. Plos One, 13(3): e0190557. DOI: 10.1371/journal.pone.0190557.
By Diana Madson on Jan 8, 2020
Yale Climate Connections
You may enjoy gazing out the window and seeing familiar birds like goldfinches, robins, or warblers flitting between tree branches. But as the climate warms, many bird species will need to leave some of the places they’ve long considered home.
“These areas just become no longer suitable, and they’ll have to move to new areas,” says Brooke Bateman, a senior scientist at the National Audubon Society. She says for bird lovers who want to visualize what this means in their own yards, Audubon created an online tool. Users can enter a ZIP code and learn more about local climate threats and the risks they pose to birds.
“It really gives you a local snapshot of what’s happening with climate change,” she says. The tool highlights which species will no longer find suitable local habitat by the end of the century. Users can toggle between different levels of future warming. Bateman says this lets people see that without climate action, “Oh, these birds that come to my feeder, or these birds I see in my backyard … they’re not going to be there anymore.”
But if carbon pollution is sharply reduced, the risks to many species are, too. The tool shows how climate action can help your favorite birds return to your feeder year after year.
Reporting credit: Sarah Kennedy/ChavoBart Digital Media.
By Bonnie Beers
Two studies published in October 2019 document changes and potential challenges facing North American bird populations:
Cornell’s study describes actual changes over the past 50 years. The Audubon study predicts population declines based on 140 million observations from 40 different data sets interfaced with habitat preferences and needs of each species and on climate change projections. The web-link above describes details of the study and allows viewing of predictions that illustrate vulnerabilities of specific species typical of a given zipcode at projected temperature rises of 1.5, 2.0, and 3.0-degree Celsius.
Both studies present some grim realities, but also provide pathways for hope, at both individual and policy levels. Make a New Year’s Resolution to do something for birds!
Submitted by Charlene Uhl
Article appearing in the Washington Post, Dec. 18 2019
By Adrian Higgins Columnist
It is hard to overstate the value and cultural importance of the American chestnut tree for those who came before us.
The native hardwood was once so ubiquitous, it has been said, that a squirrel could travel from Maine to Georgia in the chestnut canopy. The largest trees, spreading 100 feet or more, dropped 10 bushels of nuts, and in the fall the ground was covered with a nut blanket four inches deep, writes sociologist Donald E. Davis in a 2005 paper.
The bears and turkeys feasted, the farmer’s hogs feasted, and the people who lived in chestnut territory feasted — on that sweetened Appalachian ham but also on the economic value of the trees and their nuts. The chestnut’s arrow-straight timber was valued for its size and rot resistance and today endures in the posts and beams of old farmhouses and barns.
For us city folk, the chestnut evokes everything that is nostalgic about yuletide season, the notion of a vendor plying hot roasted chestnuts on a street corner. The aroma, the warmth in the hand, the nutty flavor all conjure one of the more cuddly images of a Dickensian world.
, this diminished holiday custom is carried on with nuts from Asia and Europe, which are bigger but less sweet.
The American chestnut was killed off by the arrival of a blight in 1904 that within a few decades had virtually wiped out an entire, dominant species. In modern parlance the fungus, Cryphonectria parasitica, went viral.
This environmental catastrophe is widely known. Not so broadly understood is that we are closer than ever to returning the American chestnut to its old haunts — or something akin to it. This resurrection has been several decades in the making and has taken two parallel tracks. The first is in the slow, methodical work of traditional hybridization, attempting with each successive generation a tree that will be naturally resistant to the fungus. This has been led by the American Chestnut Foundation, based in Asheville, N.C. The second is by way of genetic modification, undertaken by scientists at the State University of New York in partnership with the foundation. In a world wary of organism-mixing in the lab, this has proved more controversial.
Naturally resistant trees can reach nut-bearing age before the blight knocks them back. This tree is in western North Carolina. (American Chestnut Foundation) The winter garden is full of promise and productivity.
The conventional breeding began by crossing the blight-tolerant Chinese chestnut with some surviving American chestnut individuals that had proved resistant to the fungus, if only to die back to the roots after reaching nut-bearing age.
The foundation was created in 1983 by plant scientists and others who saw the potential of systematic development of a blight-resistant tree through a series of “backcrosses” in which successive generations of American-Chinese hybrids could be bred with resistant American chestnuts. Once these crosses produced trees that were carrying chiefly the American chestnut genome — as much as 90 percent — they were crossed with each other. The challenge has been to select seedlings with enough Chinese blood in them to ward off the disease and yet still look like the American chestnut. At maturity, the American tree is tall and spreading with a thick, straight trunk. The Chinese species is shorter and more branching.
Most of this work goes on at a research station in southwest Virginia named Meadowview Research Farms. The foundation is supported by 5,000 members and chapters in 16 states.
Jared Westbrook, the foundation’s science director, said that of 60,000 seedlings planted and evaluated, 4,000 have made the cut so far. That number will be reduced to 2,000 in the coming months, and a final cut will leave 600 trees by 2021 as the culmination of the breeding program. These will be used to re-populate the Appalachian forest — though earlier-generation trees produced at Meadowview have already been planted on 40 private, state and national sites in the chestnut’s historical range. Westbrook is using a technique called genomic selection to pick the finalists — by analyzing their DNA he can identify individuals with the desired traits.
This is not to be confused with genetic modification, which is the tack employed by William Powell and his colleagues at SUNY’s College of Environmental Science and Forestry. They have used a wheat gene to counter the effects of the disease and have asked the Agriculture Department to sign off on its release. Also, Powell said, the Environmental Protection Agency will decide whether the antifungal properties constitute a fungicide, which would require pesticide registration. In addition, the Food and Drug Administration will determine whether the nuts are safe to eat.
The foundation is working with the researchers. “If it gets through the review process, the American Chestnut Foundation would breed that gene into a diverse population,” Westbrook said. “We are using all the tools available to us.”
The genetically engineered or transgenic chestnut is facing opposition from an alliance of environmental groups named StopGEtrees, which claims its release into the wild would be “a massive and irreversible experiment” and pave the way for other forest tree species to be genetically engineered and released.
“This would be the first one to be released into nature,” said Rachel Smolker, co-author of a report critical of the plan. The restoration of the American chestnut is such an appealing idea that the proponents of genetic engineering are using it to win acceptance of the broader biotechnology, she says. “It’s about winning public support for genetically engineered trees, which has met with tremendous public resistance,” she said. “It’s a very deliberate strategy. A tree engineered for biofuels doesn’t win over the public in the same way.”
Powell says the bacterium he used to carry the wheat gene into the chestnut chromosome is already found, naturally, in the DNA of some tree species, including the walnut. “Walnut is a natural GMO,” he said. The biotechnology “can be applied to other trees,” he says. “But it’s a good thing, it can save more trees.”
This fall, residents of the Lyon Park neighborhood of Arlington County gathered in their community park to plant two non-transgenic saplings from the chestnut foundation to mark Lyon Park’s centennial. They are just a few inches tall, but they are latent giants. “We are protecting them and doing the best we can,” said resident Gray Handley. A hundred years after the demise of the American chestnut, there is hope that future generations will witness something denied ours, the return of the big old American chestnut.
by Jeff Stehm
More rapid than eagles his coursers they came,
And he whistled, and shouted, and called them by name:
"Now, Dasher! now, Dancer! now Prancer and Vixen!
On, Comet! on, Cupid! on, Donner and Blitzen!
To the top of the porch! to the top of the wall!
Now dash away! dash away! dash away all!"
As leaves that before the wild hurricane fly,
When they meet with an obstacle, mount to the sky;
So up to the housetop the coursers they flew….
He sprang to his sleigh, to his team gave a whistle,
And away they all flew like the down of a thistle.
But I heard him exclaim, ere he drove out of sight--
“Happy Christmas to all, and to all a good night!”
Excerpt from “A Visit from St. Nicholas”
By Clement Clarke Moore
Christmas is approaching and with it, undoubtedly, comes a yearning in the hearts of master naturalists for a better understanding of reindeer. So here are some fun facts about reindeer to entertain the holiday crowds.
And did you know that Rudolf’s red nose is not an anomaly. Most reindeer have red noses as a result of a dense network of capillaries that carry blood to the nose and keep it warm in the cold environment as well as help regulate the reindeer’s body temperature.
Now if you really want to impress your holiday guests with the extraordinary depth of your master naturalist training, here are a few scientific points for recitation at Christmas dinner (be sure there is plenty of eggnog):
Happy Holidays and Merry Christmas!
Submitted by Barry Buschow
Commercial pumpkin growers routinely rent honey bees so they have enough insects to pollinate their crops, but a new study published in the Journal of Economic Entomology suggests that wild bees can do the job for free. The three-year study found that wild bumble bees and squash bees could easily handle the pollination required to produce a full yield of pumpkins in all of the tested commercial fields, according to Carley McGrady, the lead author of the study.
The pumpkin study was part of a broader initiative, called the Integrated Crop Pollination Project, or Project ICP (http://icpbees.org/), which was headquartered at Michigan State University and funded by the U.S. Department of Agriculture’s Specialty Crop Research Initiative. To read more, click here.
Big Money Is Building A New Kind Of National Park In The Great Plains
NPR, Nate Hegyi, December 8, 2019 · 6:00 AM ET
Richmond Times-Dispatch, November 30, 2019 (BY DEVI LOCKWOOD, The New York Times)
(submitted by Charlene Uhl, Class X)
Physiologically, the hibernation period is the strangest, and the most compelling, to researchers. When a bear hibernates, its metabolic rate and heart rate drop significantly. It does not defecate or urinate. The amount of nitrogen in its blood rises sharply, without damaging the kidneys or liver. The animal becomes resistant to insulin but doesn't suffer from fluctuations in its blood sugar levels. To read the full article, click here.
By SANDY HAUSMAN, Radio IQ WVTF, NOV 29, 2019
(submitted by Barry Buschow)
Hundreds of people spends each spring and summer checking on baby birds in their neighborhood. They’re part of a national effort to bring back bluebirds after their population dropped 90%. You might expect those volunteers to retire in the fall, but one bird lover from Virginia is busier than ever.
200 years ago, eastern bluebirds were common in Virginia. Settlers would find their nests in the holes of trees, but the situation changed as farmers took down forests and non-native species arrived in America – cavity nesters that compete with bluebirds.
“One of them was house sparrows, and another is the starling, and those two species of birds are now the two most populous of all bird species in North America, ” says Clark Walter, a man who played professional basketball in Europe in his youth. He stands 6-foot-six but has great compassion for smaller creatures. “Bluebirds are tiny little things, and they just weren’t winning the war against the starlings and the house sparrows,” he explains.
Now retired from the Cleveland Zoological Society, Walter knew it was possible to help bird populations recover.
“I’ve had some exposure with Andean condors into Venezuela or Trumpeter swans in the state of Ohio, but I didn’t know much about my own backyard,” Walter admits.
So he became a master naturalist and built a trail through his Albemarle County neighborhood, putting up specially designed boxes for bluebirds. He turned his garage into a cozy workshop with a wood stove and more than a dozen antiques, including a cabinet with 125 tiny drawers that supplied a 19th century pharmacy.
“They held different medicines, things like arsenic and turpentine and other sorts of things that we probably wouldn’t want to take today,” he muses Now they’re filled with screws and nails he uses to build cedar bluebird boxes he sells for the cost of the materials. In his first year, he made 65 of them. “The following year I was building a couple of hundred," Walter recalls. "The next year 400, and the next year 600, and a couple of years ago 700.”
Each comes with a pole and a baffle that protects the birds, their eggs and babies from predators. “We love housecats, and we have one of them, but they take a heavy toll on the bird population, in the billions. Also, snakes, raccoons and bears.” Actually, there’s no stopping the bears. Walters says they’ve destroyed five bluebird houses in the last three years in his neighborhood alone. Still, the birds are prolific, often raising two broods in a season and sometimes three or four.
“You clear out the old nest and that prompts the parents to build a new one," he explains. "It takes them a day or two, and then they lay another set of eggs and raise them until fledging.” The bluebird population has grown more than two percent a year since the sixties, but Clark Walter plans to keep building boxes. He’ll finish this year’s batch at the end of November. Then it’s on to his next project -- a seasonal business called Captain Breck's Rum Cakes. Like the birds, he’s a productive guy. Next month, in the kitchen he shares with his sweetheart Connie Friend, he’ll
bake, pack and ship a thousand cakes made with twenty cases of rum.
Click Here for Audio of this Interview.
by Jeff Stehm
In early November, I had the special pleasure of spending a few hours in the British Natural History Museum. Similar to the Smithsonian Natural History Museum, a few hours does not do it justice, but I had a plane to catch. Below is a slide show of photos I took as I ran through the museum and a video at the end. Hope you enjoy them.
Seeing a ton of acorns on the ground? It must be a ‘mast’ year for oaks.
By Emily Moran, Washington Post 11.26.19
(submitted by Charlene Uhl, Class X)
If you have oak trees in your neighborhood, perhaps you’ve noticed that some years the ground is carpeted with their acorns, and some years there are hardly any. Biologists call this pattern, in which all the oak trees for miles around make either lots of acorns or almost none, “masting.”
In New England, naturalists have declared this fall a mast year for oaks: All the trees are making tons of acorns all at the same time. Many other types of trees, from familiar North American species such as pines and hickories to the massive dipterocarps of Southeast Asian rainforests, show similar synchronization in seed production. But why and how do trees do it?
Every seed contains a packet of energy-rich starch to feed the baby tree that lies dormant inside. This makes them a tasty prize for all sorts of animals, from beetles to squirrels to wild boar.
If trees coordinate their seed production, these seed-eating animals are likely to get full long before they eat all the seeds produced in a mast year, leaving the rest to sprout.
For trees like oaks that depend on having their seeds carried away from the parent tree and buried by animals like squirrels, a mast year has an extra benefit. When there are lots of nuts, squirrels bury more of them instead of eating them immediately, spreading oaks across the landscape.
Getting in sync
It’s still something of a mystery how trees synchronize their seed production to get these benefits, but several elements seem to be important. First, producing a big crop of seeds takes a lot of energy. Trees make their food through photosynthesis: using energy from the sun to turn carbon dioxide into sugars and starch. There’s only so many resources to go around, though. Once trees make a big batch of seeds, they may need to switch back to making new leaves and wood for a while, or take a year or two to replenish stored starches, before another mast.
But how do individual trees decide when that mast year should be? Weather appears to be important, especially spring weather. If there’s a cold snap that freezes the flowers of the tree — and yes, oaks do have flowers, they’re just extremely small — then the tree cannot produce many seeds the following fall.
A drought in the summer could also kill developing seeds. Trees will often shut the pores in their leaves to save water, which also reduces their ability to take in carbon dioxide for photosynthesis.
Because all the trees within a local area are experiencing essentially the same weather, these environmental cues can help coordinate their seed production, acting like a reset button they’ve all pushed at the same time.
A third intriguing possibility that researchers are still investigating is that trees are “talking” to one another via chemical signals. Scientists know that when a plant is damaged by insects, it often releases chemicals into the air that signal to its other branches and to neighboring plants that they should turn on their defenses. Similar signals could potentially help trees coordinate seed production.
Investigation of tree-to-tree communication is still in its infancy, however. For instance, ecologists recently found that chemicals released from the roots of the leafy vegetable mizuna can affect the flowering time of neighboring plants. While this sort of communication is unlikely to account for the rough synchronization of seed production over dozens or even hundreds of miles, it could be important for syncing up a local area.
Masting and the food web
Whatever the causes, masting has consequences that flow up and down the food chain. For instance, rodent populations often boom in response to high seed production. This in turn results in more food for rodent-eating predators such as hawks and foxes; lower nesting success for songbirds, if rodents eat their eggs; and potentially higher risk of transmission of diseases such as hantavirus to people. If the low seed year that follows causes the rodent population to collapse, the effects are reversed.
The seeds of masting trees have also historically been important for feeding human populations, either directly or as food for livestock. Acorns were a staple in the diet of Native Americans in California, with families carefully tending particular oaks and storing the nuts for winter. In Spain, the most prized form of ham still comes from pigs that roam through the oak forests, eating up to 20 pounds of acorns each day.
So the next time you take an autumn walk, check out the ground under your local oak tree — you might just see the evidence of this amazing process.
Emily Moran is assistant professor of Life and Environmental Sciences at the University of California at Merced. This report was originally published on theconversation.com.
Washington Post 11.26.19
by Jeff Stehm
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For the more ambitious, check out the Taxonomic Certification Program
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