4/24/2008  Moose and Wolves on Isle Royale. 

[Global warming impacts the balance of predator and prey.]

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3/6/2008   Critical Habitat for the Canada Lynx

 The Canada Lynx (Lynx Canadensis) is a feline about double the size of the domestic cat, 30-35 inches in length and 18-20 pounds in weight. Members of this species have white-tipped ruff fur, often giving them a silvery appearance.  Their legs are long, and their feet large and furry, enabling them to traverse snow more easily than bobcats and coyotes,  possible competitor predators. Although they may resort to rodents and small birds, their diet consists mainly of the snowshoe hare; hence they share the habitat of the hare, especially boreal forests with conifers and abundant snow. Their population cycles are synchronous with those of the hare. They are widespread in Canada and Alaska , and populations exist in Montana , Idaho , and Washington ; they have been found rarely in Minnesota , Wisconsin , and New England .

   Due to human activities such as trapping, hunting, construction, and forest fuels reduction, habitat and numbers of this species have declined to dangerously low levels.  In 2000, the Canada Lynx was listed as endangered, pursuant to criteria established in the Endangered Species Act.

   On February 28, 2008, the U.S. Fish and Wildlife Service proposed increasing the specified critical habitat of the lynx by 40,913 square miles, including approximately 8000 square miles in northeastern Minnesota and 10,000 square miles in Maine, especially on lands around Moosehead Lake. (The total may include not only areas presently populated by the species but unoccupied areas which scientific data suggest are critical to the conservation of the species.) On the specified area in Maine, a developer known as Plum Creek has proposed a massive project to include 2000 dwellings, five commercial districts, and two large resorts.

   The U.S. Fish and Wildlife proposal is welcomed by local conservation organizations such as the Natural Resources Council of Maine and RESTORE; The North Woods. The USFWS invites comments, especially of a scientific nature, to be submitted by April 28, 2008, electronically, following instructions at http//www.regulations.gov, or by mail to:   Public Comments Processing , [Attn: [FWS-R6-ES-2008-0026], Division of Policy and Directives Management,   U.S. Fish and Wildlife Service, 4401 N. Fairfax Drive,   Arlington , VA 22203

Sources: Federal Register 73, #40, pp. 10860ff;  ENVIRONEWS, The Natural Resources Council of Maine, February 28, 2008.                                                                                                                                                                                                                                                --Robert M. Davis

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2/4/2008    The Impact of Global Warming on the Gray Jay

The gray jay or Canada jay (Perisoreus canadensis) is larger than a robin  (eleven to thirteen inches), with head markings similar to those of a chickadee.  It inhabits the boreal spruce and fir forests of North America. In the fall it hoards perishable food, up to fifty pounds per individual, hiding berries and even moose flesh in spruce bark and needle piles. Counter-intuitively, it would seem, it breeds in February, producing three to four eggs in a few weeks in late winter.

Naturalists have documented a fifty percent decline in the gray jay population in one area of its range, the Algonquin Provincial Park of Ontario, an instance of species range contraction rather than shift. In an article published in Proceedings of the Royal Society B, author Dan Strickland (former chief naturalist of the Park) and Tom Waite (a biologist from Ohio State University), using their research and that of Russ Rutter (a Park naturalist in the 1960s), show that this decline is in fact a result of global warming.

The annual temperature at Algonquin has been rising about 0.7 degrees F. per decade. When the fall is warmer than usual, the stored food starts to rot, causing a shortage that is especially harmful in an ensuing hard winter. The resultant loss of nutrients and energy causes, in turn, breeding failures, fewer eggs and therefore an insufficient number of replacements of the adult population. The social structure is also affected: whereas these birds used to mate for life, many of them now re-mate following the loss of a mate or a breeding failure, with consequent mismatches in age and experience.

 (Summary by Robert M. Davis of Cynthia Berger, “Winter’s Early Birds,” National Wildlife, Feb.-March 2008, pp. 47-50, supplemented with information from Roger Tory Peterson and Virginia Marie Peterson,  A Field Guide to Birds of Eastern and Central North America, 5th ed. [Boston: Houghton Miflin, 2002]).   

 

Assessing the Effects of Climate Change on Wildlife

      To assess the impact of climate change on wildlife in the area of Concord, Massachusetts, researchers from Boston University are comparing spring time events in the mid-nineteenth century with those at the present time.  For the nineteenth-century, they have compiled biological data collected by Henry David Thoreau and other citizen scientists, along with records from Arnold Arboretum.  Their data for the current situation comes from thrice weekly visits in the spring and summer over the past five years to Concord.

       Weather records show that the average spring temperature of Concord has increased 4.5 degrees Fahrenheit since the 1850s when Thoreau kept records.  A large part of the change must be ascribed to the urbanization of the area, but some presumably is due to overall global warming.  Researchers have found that the high-bush blueberry is blooming approximately two weeks earlier and the yellow wood sorrel about a month earlier than they did in Thoreau's day.  Wood ducks are arriving about a month earlier and ruby-throated hummingbirds about 18 days earlier.  A great danger is that events will no longer synchronize correctly.  For example, a species of birds may arrive before a species of insects on which it depends hatch.

       To acquire data on the impact of global warming on wildlife across the country, a consortium of academic institutions and U.S. government agencies, funded by the National Science Foundation, has created the National Phenological Network.  In the network's words "phenology is the  study of periodic plant and animal life cycle events and how these are influenced by seasonal and international variations in climate."  In 2007 the network tested a Project BudBurst, and it will launch the program nationally in 2008.  Through it citizens will be able to contribute information on the phenophases of specific plant species.  For basic information on the network, go to www.usanpn.org.  Subscribe to a mailing list for Project BudBurst at  www.budburst.org .  

Sources:

Nickens, T. Edward.  "Walden Warming," National Wildlife (October/November 2007) 45, no. 6, pp. 36-41.

The National Phenological Network.  Websites: www.usanpn.org and www.budburst.org, accessed October 13, 2007.

                                                                                                                                   --posted October 14, 2007

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The Ecological Value of Beavers

             At a conference in China in June, biologist Sharon Brown gave a presentation about the value of beavers for restoring wetlands and even for reducing the release of the greenhouse gas carbon dioxide.  As is well known, freshwater wetlands filter water, host wildlife, and moderate the flow of streams.  “Beavers build leaky dams that enhance these functions.  For example, up to 90 percent of the silt in a stream can be removed by a beaver dam,” Brown said.  Furthermore, the plants growing in wetlands absorb carbon dioxide. 

            China has only about eight hundred beavers.  Brown suggested restoring the beaver population there and studying whether relocating pairs of beavers to dry areas, in particular the large areas planted with hybrid poplar, would improve the quality and the supply of water.  Sixteen other countries are currently working on beaver restoration, because of their importance in restoring wetlands.

            Brown was speaking at the Conference on Global Warming, Conservation of Energy and Renewables at Wuhan University .  The organization for which she is biologist, Beavers: Wetlands and Wildlife, has a Web site at www.beaversww.org.

Sources: Beavers: Wetlands and Wildlife. “Beaver Damming Alleviates Water Woes—and Combats Global Warming; a New DVD Shows How [News release].”  July 9, 2007.

                                                                               --posted July 24, 2007

Importance of Major Predators

            An article in Biological Conservation underlines the essential role played by top predators in maintaining ecosystems.  Researchers at Oregon State University compare the health of Zion Canyon with that of a nearby watershed.  In Zion Canyon , which has received throngs of visitors since the early 1900s, cougars are now virtually absent.  The other watershed, more remote and seldom visited, has an intact cougar population.  As a result of the disappearance of cougars and an end to the fear of cougars in Zion Canyon , mule deer  have devoured the canyon’s young cottonwood trees, eventually causing the deforestation and erosion of stream banks. This in turn has resulted in “the decline or disappearance of shrubs, wetland plants, amphibians, lizards, wildflowers, and even butterflies,” Robert Beschta sums up.  In the other watershed fifty times more cottonwood trees are present, along with varied wildlife, including plants that help stabilize the stream banks.  The research findings parallel those of recent studies on the cascading effects of the decline of wolves in the western United States .  

Source:  Press release from Oregon State University , dated October 24, 2006 and available at www.eurekalert.org/pub_releases/2006-10/osu-cpk102406.php .

                                                                                   --posted October 28, 2006

Endangered Beach Mice Help Save Developments

            An article in the September/October issue of Audubon (“Beach Blanket” by T. Edward Nickens, pp. 24-28) points out that in Gulf Shores, Alabama, developers have to thank Alabama and Perdido Key beach mice for, in effect, forcing setbacks to save critical habitat.  In 1994 the intact dunes that had to be left in place for the mice, prevented the winds and the surge of Hurricane Ivan from destroying buildings. 

            The article clearly explains the cycling of sand, which results in the protection of property and natural areas inland from dunes.  In a storm, the surge removes sand from the face of dunes and deposits it just offshore where it forms submerged bars.  The bars blunt the force of the incoming water and wind. After the storm subsides, tides gradually push the sand on the submerged bars back to the shore to rebuild the dunes.

            The continued existence of the dunes at Gulf Shores is no accident.  Conservationists have fought long and hard to preserve them to save the mice, which live among and within them.  The chronicle of the struggle goes back at least as far as an article in the summer 1992 issue of Wild Earth in which Ray Vaughn described the plight of the Endangered Perdido Key Beach Mouse (Peromyscus pollionotus trissyllepsis), which lived only on the narrow island Perdido Key.   That year Vaughan and Ned Mudd represented the Alabama Conservancy and an individual in a suit against the US Department of Interior and the US Fish and Wildlife Service for their failure to protect the mice from apparent threats posed by development on the island.  Additional legal actions were later necessary.

Diversity of Soil Bacteria

            In "The Diversity and Biogeography of Soil Bacterial Communities," Noah Fierer and Robert B. Jackson present the results of an analysis of bacteria in ninety-eight soil samples from across North and South America.  They found that the diversity of bacterial communities differed in various types of ecosystems, and that the degree of diversity was largely determined by soil pH.  Acidic soils, such as those in the Amazon rain forest, support few bacteria; neutral soils, such as those in relatively dry grasslands in Nevada, support highly diverse bacterial communities.  The complete article, which was published in the January 17, 2006, online issue of  Proceedings of the National Academy of Sciences (PNAS), can be reached through the Web site of Noah Fierer, who teaches at the University of Colorado in Boulder.  The Web site, <http://www.colorado.edu/eeb/EEBprojects/FiererLab/>, also gives access to other articles by him..

                                                                                                                                                                ---Posted August 19, 2006 _________________________________________________________________________________________________________________                                                                                                                                                           

Adirondack Inventory

            The Adirondack All Taxa Biodiversity Inventory (ATBI) Project Plan has been completed and is posted at http://library.paulsmiths.edu/atbi/index.htm. 

                                                                                                                                                                  ---Posted August 6, 2006

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Previously Undescribed Species Reported in the Adirondacks

             Heather Root, a graduate student at the State University of New York’s College of Environmental Science and Forestry, has found high in old Sugar Maples in Adirondack Park, three mites that had not previously been described and a foliose lichen that had previously been reported only once in New York.  Mites are tiny arachnids related to spiders.  The lichen, a folios (leaflike) lichen, had been reported on Long Island in the 1960s.  Root’s co-major professor Gregory McGee believes that she and her field assistant Howard Prescott may be the first people to study biodiversity in the forest canopy of the Northeastern United States .

            The purpose of Root’s research was to find out if lichen and mite communities differ in old and managed stands.  Her managed stands included selection system forests and reserve shelterwood stands, both cut from old-growth forest.  All her stands therefore harbored big, old Sugar Maples. She found that the lichen communities (and the mites that live in them) did not vary by type of stand but that they did vary with the size of the trees.  Large trees had a greater variety of lichens, more unique assemblages, and greater lichen cover than small trees.  Since Root examined only small areas, much may yet remain to be discovered in the Adirondack canopy.

 Sources:

Gregory McGee , Personal Communication, 2006.

SUNY College of Environmental Science.  “80 Feeet Up, Tree Top Inhabitants Pose New Questions.” [Press Release] April, 24, 2006 . 

 Old Growth and the Ivory-Billed and Pileated Woodpeckers 

(Summary by Robert M. Davis of Frances Backhouse, “Survivor,” Audubon,  Nov.-Dec. 2005, pp. 18-23.)

             Within a few months of the sighting (still disputed), reported last April, of an ivory-billed woodpecker in a swampy forest of Arkansas, the Cornell Laboratory of Ornithology received almost 2000 messages describing sightings as far north as Maine and Michigan. Since there are real similarities of appearance between the ivory-bill and the pileated but their ranges differ dramatically---the ivory-bill exists only in the southeastern United States., while the pileated is relatively common in the entire East and across the northern  United States and southern Canada---probably all of these sightings were of the latter.

             The classic contrastive description of species is that of the blueberry and the elephant: the former is blue but the latter is gray. That of the ivory-billed and the pileated woodpeckers is more complex. Both are large and predominantly black, but the patterns of white on the necks, backs, and wings, and the colors of the bills distinguish them from one another. Also, both male and female pileated woodpeckers have the bright red crest, but only the male of the ivory-bill has this feature. Though their habitats may overlap, the pileated prefers “deciduous and coniferous forests”, while the ivory-bill is limited to “mature bottomland and swampy forests”.

             Why has the ivory-billed woodpecker become nearly extinct while the pileated has recovered and now thrives? As one would expect, the answer lies in the relationship between their diets and their habitats. Most of the field research on the ivory-bill was done by James Tanner of Cornell in the 1930s. He found that this species’ diet consists especially of beetle larvae, particularly of the long-horned beetle (cerambycid), living under the bark of “large, recently dead trees.” These birds need large amounts of good-quality food “within easy flying distance of their nest.” Tanner calculated that, on average, an area of six square miles is needed to support one pair of ivory-bills. On the other hand, one square mile can support six pairs of pileated woodpeckers, which find their diet of ants (especially carpenter ants) and beetle larvae even in longer-dead trees and live trees.

             The habitat required for the ivory-bill is found only in the Southeast, and the primal forests on which it depends were almost completely cut between 1870 and the 1940s. While this destruction hurt the pileated population also, it survived because its range and food supply are much more widespread and because it can find its food and nesting sites even in fragmented habitats. Nevertheless, the practice of too frequent burning and too short a cycle of cultivation and cutting of lumber (15-25 years) would endanger the pileated woodpecker, which depends on larger, older snags, generally 35 years old or older.

                                                                                                                         --posted March 31, 2006

The Plight of the Florida Panther

 (Summary by Robert M. Davis of Abby Goodnough's  “A Rare Predator Bounces Back (Now Get It Out Of Here),” New York Times, March 14, 2006).

            There are about 100 Florida panthers, an endangered subspecies of the puma, in the area of Big Cypress National Preserve, north of the Everglades. Although scientists debate whether or not this feline still qualifies as a subspecies, especially because of cross-breeding with the Texas puma in the 1990s, they agree that the population must grow and needs more space to survive. In fact, the ideal would be “three separate populations of at least 240 each”--an unrealizable goal because of the dwindling amount of suitable habitat. Moreover, already in 2006, six panthers have been killed: one by another panther, five (including a female pregnant with four kittens) by automobiles.

            Actual cases of endangerment of humans or killing of domestic animals by Florida panthers are few in number. The panther team leader of the Florida Fish and Wildlife Commission knows of only one documented case where a Florida panther attacked a human being, and that was in the 1880s. But a few people are completely opposed to their protected status, and many others are uneasy about their presence or proximity. For example, in 2004, an Indian tribe requested the removal of a male panther, which was moved 60 miles away (and killed by another panther). More recently, the same group is worried that a female and two cubs are too close to residences and campgrounds. And one real instance of provocation occurred in February of this year when, over the course of several forays, a radio-tracked panther named Don Juan (the father of 30 kittens) entered residential properties to dispatch “chickens, ducks, a turkey, a pig, and a house cat.” So this animal was caught and removed to another area.

            Officials of the U.S. Fish and Wildlife Services and of groups seeking protection for the panther have made various proposals to mitigate or to solve the perceived problem (danger to humans and their possessions) and the proven problem (lack of adequate territory for the growth of stable Florida panther populations). Such proposals include fencing out deer, which attract panthers; removal of truly aggressive individuals from proximity to humans; “aversive conditioning” of less aggressive ones (chasing them with dogs, hitting them with slingshots); transport of some of them to Central Florida (but there is insufficient contiguous habitat there) and/or to other States they formerly inhabited, i.e. Georgia and Arkansas (but reintroduction of predators meets fierce resistance from humans, and the Florida panther population is too small to permit this anyway). Ultimately, this large predator, like others, can be saved only if humans accept their presence and cease destruction of their habitats, an unlikely prospect.

Suit on Behalf of Cerulean Warbler

             March 3, 2006 , five conservation groups filed suit against Interior Secretary Gale Norton and the US Fish and Wildlife Service (FWS) for ignoring their five-year-old petition to list the Cerulean Warbler as an endangered species. 

               The population of these warblers has decreased by almost 82% throughout its US range during the last forty years.  The bird breeds in the forests of the eastern United States in the summer and migrates to South America for the winter.  It needs “large areas of mature, undisturbed forest to reproduce successfully,” National Audubon reports.  The warbler thus appreciates and uses old growth.

               The logging and fragmentation of mature forests in the United States and in the Andes and northern South America are major causes of the bird’s decline.  Listing the bird would require FWS to develop a recovery plan and ensure that actions of the federal government do not hinder its recovery.

            The suing organizations are Defenders of Wildlife, Heartwood, National Audubon, Southern Appalachian Biodiversity Project, and Western North Carolina Alliance.  For more information, go to www.audubon.org/news/press_releases/Cerulean_Warbler_03_03_06.html

                                                                                             --Posted March 15, 2006

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 Fire in the East, Fire in the West

 (Summary by Robert M. Davis of  Tim Wright’s “A Tale of Two Fires,” American Forester, Winter 2004, pp. 28-31)

         This article describes the divergent causes and effects of forest fires in the East and in the West, based on the examples of conflagrations in Los Alamos, New Mexico and the Shenandoah National Park in Virginia in 2000.  Shenandoah National Park supports some one hundred acres of old growth, but most of it is in hollows, which would have offered protection from fire.

         In the West, much of the moisture from ocean storms falls on the coastal mountains with the result that areas east of them are relatively dry. Lightning frequently strikes, unaccompanied by rain, setting off fires. The forests are mostly coniferous, with a high content of flammable resin. There are numerous ladder fuels”, i.e. tall grasses, low branches, and bushes. These conditions enable the fires to reach the canopy and to burn with extreme heat, destroying not only surface vegetation but also sub-surface seeds and other organisms. Hence, the fire in Los Alamos ruined a community and left a charred landscape still blackened with burnt trees and bare, lifeless ground.

          The conditions in the East are quite different. Rain usually accompanies the thunderstorms and inhibits fires. Unlike those in the West, fires in the East are usually caused by humans. The greater diversity of trees and bushes, including thick patches of mountain laurel in the Shenandoah and similar areas, is less conducive to canopy fires and to extreme burning temperatures. This area was covered largely with oaks and chestnuts at the time of the arrival of the Europeans, who cut much of the timber. The chestnuts died out by the 1930s. While building the Skyline Drive in those years, the Civilian Conservation Corps planted mountain laurel to control erosion, and these bushes have formed nearly impenetrable thickets below the forest canopy.

          The Shenandoah National Park includes 196,000 acres stretched out along a 106 mile length, with a maximum width of 15 miles. This narrow width and the relatively dense adjacent human populations necessitate a strict policy of fire suppression, resulting inevitably in the build-up of combustibles. The fire of 2000 charred 24,000 acres, affecting especially the laurels and the smaller trees. But four years later, new growth on and close to the ground was evident, and quaking aspens, which thrive after fires, have grown back. In most places, the ground had been cleaned of fuels without damage to the root systems. In the few places where the canopy burned, sunlight has promoted the growth of flowers and berries in the cleared areas. So this burn exemplifies the beneficial results of fire. If fuels accumulate too much, the next one may be less benign.

On Murrelets

             The marbled murrelet, a small bird that lives along the U.S. Pacific Coast, modestly produces a single egg during its breeding season, if she feels up to it. This bird was listed as a threatened species in 1992 by the federal government. Its decline, as well as that of the northern spotted owl, was attributed to logging of the old-growth forests. However, a study by researchers of the University of California at Berkeley, points to an additional cause.

            An examination of the chemical composition of murrelet feathers from 1895 to 1911, saved in museums, shows that birds of those earlier years consumed a nutritious diet of oil-rich sardines, anchovies, and squid. The fishing industry has seriously depleted the numbers of these fishes, and the nitrogen isotopes coming from them are less abundant in modern-day murrelets, who have had to resort to less nutritious krill and crustaceans. Since more energy is required to dive and catch krill, less is available for reproduction and the nurture of young. Off the coast of Oregon, sardines have resurged, but this study was focused on the Monterrey Bay area of California. If valid, as seems to be the case, it suggests that the population stability of murrelets, and probably many other species, are functions of multiple factors.

 Summarized by Robert Davis, from Michael.Milstein, “Study Finds ‘Double Whammy’ Harmed Murrelet’s Population”, The Oregonian [Portland, Oregon], Jan. 3, 2006                                                                                                                

                                                                                                              --Posted February 5, 2006 __________________________________________________________

Snowmobiles and Lynx-Coyote Interactions

 One, little discussed, impact of snowmobiles is that, by compacting snow, they enable coyotes to enter high-elevation, deep-snow areas, which provide habitat for lynx.  Here, through predation and competition for food, they threaten the survival of lynx.  A study in northern Utah ’s High Uintah Wilderness found concentrations of coyote tracks around snowmobile destinations.  In another study in the same area, 30% of coyote scat found above 8000 feet contained the remains of snowshoe hare, a staple food for lynx.

 Source: George Wuerthner. Personal communication, citing Barry Gilbert. 2006. --Posted January 22, 2006

Briefs on Wildlife Populations

As coastal species of fish have declined or crashed in numbers (or have been eliminated), trawling for species in deeper waters has increased. The latter fishes grow, mature, and reproduce more slowly because of the colder water. Thus they are at risk of quicker depletion. Researchers from Memorial University of Newfoundland report that in a 17 year period beginning in 1978, the populations of five species (roundnose grenadier, onion-eye grenadier, blue hake, and spinytail skate) have declined by 89%.  (New York Times, January 5, 2006)

 Biologists appear to be succeeding in restoring the populations of native fish species in the Colorado River (such as speckled dace, blueheads, flannelmouth suckers, and chubs) by removing non-native trout. This year, more than 17,000 non-natives have been caught and killed. The numbers of trout are down and natives are again dominant in certain parts of the river, according to the Arizona Fish and Game Department. Other reports, however, warn that natives are still in danger, especially chubs, at least in part because of the consequences of the Glen Canyon Dam.   (Associated Press, November 29, 2005)

 The wiliwili is the only native dryland tree still widespread in Hawaii. But it is under attack by the tiny erythrina gall wasp, which has spread from Oahu to all the major islands. Large collections of the wiliwili are kept in the National Tropical Botanical Garden and the Waimea Valley Audubon Center, where they are being “drenched”  with an insecticide. Stores of seeds are being collected and saved, just in case... Also, biologists are seeking insect predators of African gall wasps, hoping to use them against the erythrina, with tests planned to ensure that other Hawaiian insects are not harmed.   (Associated Press December 15, 2005)

Changing Habitat in China

 The population of China, about 1.3 billion persons or approximately 21% of the world’s total, resides on roughly 10% of the earth’s surface. According to Mr. E. Jingping, China’s vice-minister for water resources, in the year 2004 alone, more than 1.6 billion tons of top soil were lost. The affected areas consist of 3.6 million hectares or 37% of the territory, especially in the region between the Yellow and Yangtse Rivers and the north of China, where the Gobi Desert is spreading, although most areas suffered some loss. From 1997 to 2004, there was a loss of 5.7% of topsoils on arable lands.  We can only hope that China’s planting of thousands of square miles of forest each year will eventually slow the rate of loss.     

 The average of water resources available per inhabitant in China is only one-quarter of the world-wide average. More than 300,000 Chinese lack access to potable water. Furthermore, groundwater supplies, providing around 70% of drinking water, are polluted, in 90% of the cities, with organic and chemical materials. 40% of the water for irrigation also comes from groundwater.

Although the article does not deal with the ramifications of these statistics, it is obvious that China ’s soil and water problems have enormous consequences, not only for agriculture and human health, but for entire ecosystems and for Asia ’s geopolitical situation.

     (Summary of an article by Christiane Gauss, “En 2004, la Chine a connu une érosion importante de ses sols”, Le Monde, Dec. 29, 2006.)

                                                                              --Robert M. Davis, posted January 10, 2006

Good Neighbors

 (Based on Carl Zimmer’s “A Pair of Wings Took Evolving Insects on a Nonstop Flight to Domination”, New York Times, November 29, 2005)

             It is always disconcerting and embarrassing to learn how little we know about our closest neighbors. A case in point is the flea, and its life and times. From the article cited above (itself based on the book Evolution of the Insects, by David Grimaldi of the American Museum of Natural History and Michael Engle of the University of Kansas), we learn that fleas exemplify the transformation of insects since they came on land over 400 million years ago. Fleas are descended from scorpionflies, which have long wings and strong eyes. The closes relatives of fleas are the 24 species of snowfleas, which have weak eyes and tiny wings and cannot fly. The 5000 other species of fleas split off from snowfleas 160 million years ago and evolved further in the same directions, i.e. they have no wings and their eyes are covered, adaptations to their new habitats, such as the hair of animals...

             Fleas are a small part of the insect kingdom, which numbers perhaps 5 million species, many more than all other animals and plants combined. Their total biomass also exceeds that of all other animals. Furthermore, they are essential to the health of forests and bodies of water. The disappearance of large numbers of the insects seems, and may be, inconceivable. Many species of insects--roaches, houseflies, and pesticide-resistant crop-eating insects, for example--have adapted to and thrive on the conditions imposed by human activities. Yet many other insect species dependent on single plant species for food or on certain habitats could be extirpated when humans destroy that habitat or that plant, and we could lose beneficent (to humans) insect species and be left with more that are inimical to us. So we owe some consideration to our six-legged neighbors.

                                                 --Robert M. Davis, posted December 30, 2005

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Evolution on the Islands

         Charles Darwin’s observations of the birds on the Galapagos Islands were an important factor in his theory of evolution by natural selection.  For a long time, however, it was generally believed that species had migrated from continents to islands and ceased to evolve there, eventually dying out and being replaced by others from the mainland.

            Some 80 years ago, Ernst Mayr challenged this view. Studying the resemblances and differences among avian species in the Pacific islands by their anatomies and colors, he laid the basis for the opposing theory: new species evolve when populations are isolated, as on islands. Christopher E. Filardi and Robert Moyle of the American Museum of Natural History have recently (see Nature, November 10, 2005) added substantial support to this theory by their study of monarch flycatchers, a group of birds species on the Pacific islands. Using  DNA from live birds on the islands and from others preserved in the museum (some from as far back as the 1880’s), they have shown that a common ancestor existing in Australia and New Guinea between 2 and 5.6 million years ago gave rise to 13 species spread out as far as Fiji and Hawaii. Some of these flycatchers re-colonized Australia and New Guinea from the Solomon Islands. Other studies suggest that islands have been the sites of similar evolutionary patterns for other animals (e.g. lizards) and even plants.

            Monarch flycatchers, like many species, are now threatened by human activities. Filardi argues that it is very important to preserve island biodiversity as a source of new biodiversity.

             Summarized by Robert M. Davis, from Carl Zimmer, “In Give and Take of Evolution, a Surprising Contribution from Islands,"New York Times, November 22, 2005

                                                                                                                                                                  --Posted December 16, 2005

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Running Buffalo Clover

            The Winter 2005 issue of The Nature Conservancy’s magazine Nature Conservancy announces that conservancy botanists have found two new populations of Running Buffalo Clover (Trifolium stoloniferum) in West Virginia .  The clover is a federally endangered species.  The populations are on land belonging to the paper company MeadWestvaco, which has agreed to work with the conservancy to preserve the clover. 

            Running Buffalo Clover was once common from West Virginia to Kansas , particularly along buffalo trails.  However, it depended on the buffalo to stir up the grand and distribute the seed.  With the disappearance of the buffalo from the East, the clover declined.  It was presumed to be extinct by 1985 when a botanist discovered a population in West Virginia . Now patches are known to exist in Missouri , Kentucky , and Ohio in addition to West Virginia .

            We accidentally came across an identified patch on the lawn of Ashland , the Henry Clay Estate, in a residential area of Lexington , Kentucky .  The clover was circled by a band of red ribbon and marked by a small sign to prevent mowing in the spring.    Running Buffalo Clover bears white flowers and creeps along the ground like white clover, but differs from that species in that the flower heads are on stems with leaves rather than on bare steams, and the leaflets are rounded and not marked by a “v.”  A brief account of the species is available online at http://www.ca.uky.edu/agc/pubs/agr/agr142/agr142.htm .  

                                                 --Mary Byrd Davis, posted November 30, 2005

Impact of the Reintroduction of Wolves in Yellowstone

             The reintroduction of wolves may be significantly altering, or correcting, the ecology of Yellowstone National Park .  Wolves disappeared from the park in the 1920s.  For the next several decades, apparently, elk happily munched on willow, cottonwood, and aspen shoots, drastically reducing the numbers and size of the these trees.  In 1995, fourteen wolves from Canada were brought to the park; seventeen more were added in 1996.  Within the next decade, this population grew to around 170 in 13 packs dispersed throughout the park, and the trees along the streams made a strong comeback as the elk moved to the uplands.  This phenomenon has enabled scientists to greatly increase the knowledge of wolf biology, much of which has been published in a book by Douglas Smith and Gary Ferguson, Decade of the Wolf: Returning the Wild to Yellowstone (The Lyons Press, 2005).

            Smith, a wolf biologist, says that “Wolves have caused a trophic [nutritional] cascade.”  William Ripple, a botanist at Oregon State University , attributes changes in vegetation and animal populations to an “ecology of fear.”  However, a canid biologist, Robert Crabtree, citing climatic factors and flooding as causes of the outbursts of tree growth along the stream banks, asserts that the wolf is not the sole source of the changes.

            The ripples through the ecology include the following:

            --where willows, cottonwoods, and aspens return, they stabilize the stream banks and shade the water, cooling it, encouraging more and larger trout;

            --these trees also attract certain avian species, such as yellow warblers and eastern sparrows;

            --beavers have also increased in number:  in 1996, there was 1 beaver dam on the northern range of the park; there are now 10;

            --the number of coyotes has decreased by half; this has increased the rodent populations and, in turn, those of red foxes and raptors;

            --the elk herd has dropped to 11,000 from 19,000 in 1994; a study indicates that 53% of the loss is caused by grizzlies who eat elk calves, only 13% by wolves, and another 11% by coyotes [who presumably take only sick or weak calves]; the herd has moved to higher, more open ground, fear making it more circumspect.

            Although not hunted, wolves face two principal dangers: 1) traffic fatalities, 24 having been killed by vehicles in 10 years; 2) the parvovirus carried into the park by domestic dogs.  The wolf population has dropped from 170 to 130 in the last year.  More time and testing are needed to determine the role of the virus and other possible factors in this decrease.

             (Summary of Jim Robbins, “Hunting Habits of Wolves Change the Ecological Balance in Yellowstone,” New York Times, October 18, 2005)

                                                                        --Robert M. Davis, posted November 8, 2005

 

The Przewalski Horse

          According to University of Kentucky biologists, cited in the excellent article by John Noble Wilford,  there are two extant species of horse: 1. all of the domestic breeds, “from Shetland pony to Clydesdale”; 2. the wild horse Equus ferus przewalskii, the Przewalski horse, or P-horse, for short, named after a Russian explorer of Polish descent who identified it in the 19th century. In Mongolia, it is called the takhi. The two species diverged from a common ancestor 500,000 years ago. Beginning about 6,000 years ago, the first was domesticated and the various breeds were developed. The takhi, however, was never tamed.  It is an animal about the size of a large pony, short-legged, tan to tawny, with a dark mane, living in families called harems, consisting of females, foals, “bachelor” males, and a dominant stallion. This wild horse roamed Central Asia until the 1960’s, when it disappeared from the wild, due to hunting and loss of habitat to livestock.

         Fortunately, there were 300 of these horses in captivity in Europe, where  breeding and  reintroduction programs were organized by the Foundation for Preservation and Protection of the Przewalski Horse, in the Netherlands. In 1992, sixteen horses were taken to Hustai National Park in Mongolia and to Tikhin Tal, a site at the western edge of the Gobi Desert. Guided by biologists and veterinarians of the International Takhi Group, several European countries  participate now in the program, and many more have been reintroduced.

         For the first year, takhi are kept within large electrified enclosures while they adapt to the cold winters and develop immunity to tick-borne diseases. There are now 300 P-horses, or takhi, in Mongolia, including 170 in Hustai National Park , the rest on remote sites at the edge of the Gobi. It is hoped that 15-20 foals will have been born this year.

         Since takhi, with 66 chromosomes, can breed with domestic horses, with 64 chromosomes, producing fertile offspring with 65 chromosomes, there is concern  about maintaining the purity of the species, if indeed it is still pure. Successive generations would regain the 66th chromosome, and some biologists believe that the added gene flow from interbreeding could be beneficial. In any event, this is another paradoxical instance of human intervention both extirpating and then, hopefully, saving a wild species.  

(Summary of John Noble Wilford, “Foal by Foal, the Wildest of Horses Is Coming Back”, New York Times, October 11, 2005.)

                                                  --Robert M. Davis, posted October 28, 2005

     ______________  

  Another Species Saved?

            There were no sightings of the black-footed ferret, a rare, nocturnal mammal that hunts prairie dogs, from 1943 to 1981, when a small colony was found in northwestern Wyoming. Since then 3000 have been bred in captivity and released in western states, including 173 in Colorado.  There is evidence that they are thriving and reproducing there, and it is estimated that there are at least 400 in South Dakota, Wyoming,  Montana, Arizona, and Colorado. Jacob Smith of the Center for Native Ecosystems, in Denver, credits the Endangered Species Act for saving this species, and points out that its continued survival depends on the protection and promotion of prairie dog populations.

 (Based on Associated Press and New York Times, September 17, 2005)

                                                             --Robert M. Davis, posted October 26, 2005

Ant Forestry

        In the Peruvian Amazon, there are areas of up to one-third of an acre dominated by a single species of tree, D. hirsuta.  Various legends and scientific theories have been put forward to explain this phenomenon. A doctoral student at Stanford University, Megan E. Frederickson, in experiments reported in the journal Nature, has shown that these monocultural tracts, called “devil’s gardens” by local inhabitants, are the work of a species of ant called M. schumanni. From its abdomen, this ant injects formic acid into saplings of species other than D. hirsuta, thus killing them off within weeks. This process of eradication benefits both D. hirsuta by giving its members more light, nutrients, and water, and M. schumanni by providing more space for its colonies. These colonies can be of enormous size and longevity.  Analysis of one colony showed that its initial construction was contemporaneous with that of some of the early gothic cathedrals (on a different continent, of course).

 (Summary of  Henry Fountain, “A Devil’s Garden, Tended by Ants”, New York Times, September 27, 2005)

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Giant Squid

      Until September 30, 2004, no giant squid had been photographed in its natural habitat. On that date, two Japanese scientists finally accomplished this, near the Bonin Islands 600 miles south of Tokyo, according to their report in the Proceedings of the Royal Society B (B for Biological Sciences).  The technology employed to view (but not personally approach) this elusive and legendary creature consisted of floating lines from which were suspended a robotic camera and hooked baits.

      The giant squid, itself prey of sperm whales, is an active predator with eight short arms and two long tentacles. The invasion of its domain ended badly for this individual. One of its eighteen foot long tentacles became caught on a hook and was torn off  when the squid finally escaped after a struggle of over four hours.

(Summarized from the New York Times, September 28, 2005)

__________

Bird Songs, Music,& Language: Is "Bow wow" Displaced by "Tweet tweet?"

        Biologists have generally regarded bird songs as means of protecting territory and attracting mates. This explanation did not satisfy Charles Darwin, who believed that birds possess a natural aesthetic sense. Because many bird songs seem to be unduly long and complicated, and not proportionately effective, Stephen Jay Gould wondered if evolution might have produced traits or activities, such as the songs and beautiful feathers of birds, that correspond to :”spandrels” in architecture, features that serve no purpose other than one of fashion or aesthetics. Dr. David Rothenberg, a professor of philosophy, amateur ornithologist, clarinetist, and composer, influenced by Paul Winters’ “Common Ground” album of the 1970s (in which calls of eagles, wolves, and whales are integrated with human music), has further pursued this question. Traveling the world for five years, he has interacted musically with various species of birds using his clarinet, an experience that has convinced him that some birds do in fact react to music, changing their songs. Thus, he believes that bird songs are not necessarily or essentially invariable or utilitarian, that they sing “because they can” and “they must”. He further wonders if “song and melody may very well have evolved before words and language”.

        Dr. Rothenberg has published an account of his experience and thought in a book, Why Birds Sing: a Journey into the Mystery of Bird Song and an accompanying CD of human and bird music.

(Summary of Claudia Dreyfus, “A Conversation with David Rothenberg”, New York Times, September 20, 2005)

                                                                                                                                                                                  ---Robert M. Davis, posted October 14, 2005

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