Want Healthy Floodplains and Streams? Want Clean Water? Then Make Room for the Beaver

I’m worried about the beaver.  Here’s why.

Imagine a network of brooks and rivulets meandering through a mosaic of shrubby, sometimes boggy, marshland, purifying water and absorbing high volumes of flow during storm events.  This was a typical low-gradient stream in the valleys of the Lower Susquehanna River Watershed in the days prior to the arrival of the trans-Atlantic human migrant.  Then, a frenzy of trapping, tree chopping, mill building, and stream channelization accompanied the east to west waves of settlement across the region.  The first casualty: the indispensable lowlands manager, the North American Beaver (Castor canadensis).

Beaver Traps
Nineteenth-century beaver traps on display in the collection of the State Museum of Pennsylvania in Harrisburg.  Soon after their arrival, Trans-Atlantic migrants (Europeans) established trade ties to the trans-Beringia migrants (“Indians”) already living in the lower Susquehanna valley and recruited them to cull the then-abundant North American Beavers.  By the early 1700s, beaver populations (as well as numbers of other “game” animals) were seriously depleted, prompting the Conoy, the last of the trans-Beringia migrants to reside on the lower Susquehanna, to disperse.  The traps pictured here are samples of the types which were subsequently used by the European settlers to eventually extirpate the North American Beaver from the Lower Susquehanna River Watershed during the 1800s.

Without the widespread presence of beavers, stream ecology quickly collapsed.  Pristine waterways were all at once gone, as were many of their floral and faunal inhabitants.  It was a streams-to-sewers saga completed in just one generation.  So, if we really want to restore our creeks and rivers, maybe we need to give the North American Beaver some space and respect.  After all, we as a species have yet to build an environmentally friendly dam and have yet to fully restore a wetland to its natural state.  The beaver is nature’s irreplaceable silt deposition engineer and could be called the 007 of wetland construction—doomed upon discovery, it must do its work without being noticed, but nobody does it better.

North American Beaver diorama on display in the State Museum of Pennsylvania in Harrisburg.
North American Beaver diorama on display in the State Museum of Pennsylvania in Harrisburg.  Beavers were reintroduced to the Susquehanna watershed during the second half of the twentieth century.
A beaver dam on a small stream in the Lower Susquehanna River Watershed.
A beaver dam and pond on a small stream in the Lower Susquehanna River Watershed.
Floodplain Wetlands Managed by North American Beavers
Beaver dams not only create ponds, they also maintain shallow water levels in adjacent areas of the floodplain creating highly-functional wetlands that grow the native plants used by the beaver for food.  These ecosystems absorb nutrients and sediments.  Prior to the arrival of humans, they created some of the only openings in the vast forests and maintained essential habitat for hundreds of species of plants as well as animals including fish, amphibians, reptiles, and birds.  Without the beaver, many of these species could not, and in their absence did not, exist here.
The beaver lodge provides shelter from the elements and predators for a family of North American Beavers.
Their newly constructed lodge provides shelter from the elements and from predators for a family of North American Beavers.
Sandhill Cranes Visit a Beaver-managed Floodplain in the lower Susquehanna valley
Floodplains managed by North American Beavers can provide opportunities for the recovery of the uncommon, rare, and extirpated species that once inhabited the network of streamside wetlands that stretched for hundreds of miles along the waterways of the Lower Susquehanna River Watershed.
Great Blue Heron
A wintering Great Blue Heron is attracted to a beaver pond by the abundance of fish in the rivulets that meander through its attached wetlands.
Sora Rail in Beaver Pond
Beaver Ponds and their attached wetlands provide nesting habitat for uncommon birds like this Sora rail.
Wood Duck feeding on Lesser Duckweed in Beaver Pond
Lesser Duckweed grows in abundance in beaver ponds and Wood Ducks are particularly fond of it during their nesting cycle.
Sandhill Cranes feeding among Woolgrass in a Beaver Pond
Beaver dams maintain areas of wet soil along the margins of the pond where plants like Woolgrass sequester nutrients and contain runoff while providing habitat for animals ranging in size from tiny insects to these rare visitors, a pair of Sandhill Cranes (Antigone canadensis).
Sandhill Cranes feeding among Woolgrass in a floodplain maintained by North American Beavers.
Sandhill Cranes feeding among Woolgrass in a floodplain maintained by North American Beavers.

Few landowners are receptive to the arrival of North American Beavers as guests or neighbors.  This is indeed unfortunate.  Upon discovery, beavers, like wolves, coyotes, sharks, spiders, snakes, and so many other animals, evoke an irrational negative response from the majority of people.  This too is quite unfortunate, and foolish.

North American Beavers spend their lives and construct their dams, ponds, and lodges exclusively within floodplains—lands that are going to flood.  Their existence should create no conflict with the day to day business of human beings.  But humans can’t resist encroachment into beaver territory.  Because they lack any basic understanding of floodplain function, people look at these indispensable lowlands as something that must be eliminated in the name of progress.  They’ll fill them with soil, stone, rock, asphalt, concrete, and all kinds of debris.  You name it, they’ll dump it.  It’s an ill-fated effort to eliminate these vital areas and the high waters that occasionally inundate them.  Having the audacity to believe that the threat of flooding has been mitigated, buildings and poorly engineered roads and bridges are constructed in these “reclaimed lands”.  Much of the Lower Susquehanna River Watershed has now been subjected to over three hundred years-worth of these “improvements” within spaces that are and will remain—floodplains.  Face it folks, they’re going to flood, no matter what we do to try to stop it.  And as a matter of fact, the more junk we put into them, the more we displace flood waters into areas that otherwise would not have been impacted!  It’s absolute madness.

By now we should know that floodplains are going to flood.  And by now we should know that the impacts of flooding are costly where poor municipal planning and negligent civil engineering have been the norm for decades and decades.  So aren’t we tired of hearing the endless squawking that goes on every time we get more than an inch of rain?  Imagine the difference it would make if we backed out and turned over just one quarter or, better yet, one half of the mileage along streams in the Lower Susquehanna River Watershed to North American Beavers.  No more mowing, plowing, grazing, dumping, paving, spraying, or building—just leave it to the beavers.  Think of the improvements they would make to floodplain function, water quality, and much-needed wildlife habitat.  Could you do it?  Could you overcome the typical emotional response to beavers arriving on your property and instead of issuing a death warrant, welcome them as the talented engineers they are?  I’ll bet you could.

A Century of Extinction

Many are wont to say that they have no capacity for scientific pursuits, and having no capacity, they consequently have no love for them.  I do not believe, that as a general thing, a love for science is necessarily innate in any man.  It is the subject of cultivation and is therefore acquired.  There are doubtless many, whose love for these and kindred pursuits is hereditary, through the mental biases and preoccupations of their progenitors, but in the masses of mankind it is quite otherwise.  In this consists its redeeming qualities, for I do not think the truly scientific mind can either be an idle, a disorderly, or a very wicked one.  There may be scientific men, who, forgetful of its teachings, are imperious and ambitious–who may have foregone their fealty to their country and their God, but as a general thing they are humble, social and law-abiding.  If, therefore, there is a human being who desires to break off from old and evil associations, and form new and more virtuous ones, I would advise him to turn his attention to some scientific specialty, for the cultivation of a new affection, if there are no other and higher influences more accessible.  In this pursuit he will, in time, be enabled to supplant the old and heartfelt affection.  The occupation of his mind in the pursuit of scientific lore will wean him from vicious, trivial, and unmanly pursuits, and point out to him a way that is pleasant and instructive to walk in, which will ultimately lead to moral and intellectual usefulness.  I wish I was accessible to them, and possessed the ability to impress this truth with sufficient emphasis upon the minds of the rising generation.  This fact, that in all moral reformations, a love for the opposite of any besetting evil must be cultivated, before that evil can be surely eradicated, has been too much overlooked and too little valued in moral ethics.  But true progress in this direction implies that, under all circumstances, men should “act in freedom according to reason.”

                                                                            -Simon S. Rathvon

 

In the cellar of the North Museum on the campus of Franklin and Marshall College in Lancaster, Pennsylvania, is an assemblage of natural history specimens of great antiquity.  The core of the collection has its origins in the endeavors of a group of mid-to-late nineteenth-century naturalists whose diligence provided a most thorough study of the plants and animals found within what was at the time America’s most productive farming county.

The members of the Linnaean Society of Lancaster City and County shared a passion for collecting, identifying, classifying, and documenting the flora and fauna of the region.  Some members were formally educated and earned a living in the field of science, but the majority were in the process of self-education and balanced their natural history occupation with an unrelated means to provide financially for their families.  The latter benefited greatly from their associations with the former, gaining expertise and knowledge while participating in the functions of the group.

On February 24, 1866, Simon S. Rathvon, the society’s Treasurer, read an essay in commemoration of the group’s fourth anniversary.  Rathvon earned a living as a tailor, first in Marietta, a thriving river town at the time, then in Lancaster City.  In 1840, Rathvon was elected into the Marietta Natural History Lyceum where, as a collections curator, he became associated with principals Judge John J. Libhart, an amateur ornithologist, and Samuel S. Haldeman, a geologist and soon to be widely-known malacologist.  Haldeman, in 1842, upon noticing the new member’s interest in beetles and other insects, provided books, guidance, and inspiration, thus intensifying Rathvon’s study of entomology.  Rathvon’s steadfast dedication eventually led to his numerous achievements in the field which included the publication of over 30 papers, many on the topic of agricultural entomology.  Rathvon’s scientific understanding of insect identification and taxonomy was a foundation for his practical entomology, which moved beyond mere insect collection to focus upon the study of the life histories of insects, particularly the good and bad things they do.  He then applied that knowledge to help growers solve pest problems, often stressing the value of beneficial species for maintaining a balance in nature.  From 1869 through 1884, Rathvon edited and published Lancaster Farmer, a monthly (quarterly from 1874) agricultural journal in which he educated patrons with his articles on “economic entomology”.  Rathvon continued earning a living in the tailor business, seemingly frustrated that his financially prudent advice on insect control in Lancaster Farmer failed to entice more would-be readers to part with the one dollar annual subscription fee.  For many years, Rathvon crafted articles for local newspapers and wrote reports for the United States Department of Agriculture.  In recognition of his achievements, Simon Rathvon received an honorary Ph.D. from Franklin and Marshall College in 1878.

In Rathvon’s anniversary essay, he details the origins of the Linnaean Society as a natural science committee within the “Lancaster Historical, Mechanical, and Horticultural Society” founded in 1853.  The members of the committee, not finding sufficient support within the parent organization for their desired mission, “the cultivation and investigation of the natural history of Lancaster County…”, sought to form an independent natural history society.  In February of 1862, the “Linnaean Society of Lancaster City and County” was founded to fulfill these ambitions.

Above all else, the written works by the members of the Linnaean Society and their predecessors have provided us with detailed accounts of the plants and animals found in Lancaster County, and in the lower Susquehanna River valley, using scientific binomial nomenclature, a genus and species name, as opposed to the variable folk and common names which, when used exclusively, often confuse or mislead readers.  Consider the number of common names a species could have if just one was assigned by each of the languages of the world.  Binomial nomenclature assigns one designation, a genus name and species name, in Latin, to each life-form (such as Homo sapiens for Humans), and it is adopted universally.

Rathvon would say of the naming of the Linnaean Society:

“…the name which the Society has adopted is in honorable commemoration of LINNAEUS, the great Swedish naturalist—one who may be justly regarded as a father in Natural Science.  To him belongs the honor of having first promulgated the “binomial system of nomenclature,” a system that has done more to simplify the study of natural science than any light that has been brought to the subject by any man in any age.”

Carl Linnaeus lived from 1707 to 1778, and published his first edition of Systema Naturae in 1735.

The names of a number of the members and corresponding members on the Linnaean Society of Lancaster City and County’s rolls remain familiar.  John P. McCaskey (educator) served as Corresponding Secretary.  Doctor Abram P. Garber was a prominent Lancaster botanist and society member.  Professor Samuel S. Haldeman (naturalist, geologist, and philologist), Professor J. L. LeConte (entomologist), Judge John J. Libhart, Professor Asa Gray (botanist), and the foremost legal egalitarian in the United States House of Representatives, the Honorable Thaddeus Stevens, were  listed among the roster of corresponding members.

By the end of its fourth year, Rathvon enumerated the specimens in the collections of the society to exceed 32,000.  These included all the species of mosses and plants known in the county, 200 bird specimens, an enormous insect collection with nearly 12,000 Coleoptera (Beetles), and more than 1,400 mollusk shells.  The work of the society had already provided a thorough baseline of the flora and fauna of the lower Susquehanna River valley and Lancaster County.

Rathvon would continue as Treasurer and primary curator through the group’s first twenty-five years, their most active.  By 1887, their library contained over 1,000 volumes, they possessed over 40,000 specimens, and more than 600 scientific papers had been read at their meetings.

Many of the society’s specimens were moved to the custody of Franklin and Marshall College following the group’s dissolution.  In 1953, the collection found a home on the F&M campus at the newly constructed North Museum, named for benefactor Hugh M. North, where many of the specimens, particularly the birds, are on prominent display.

Among the mounted specimens in the North Museum collection is a Heath Hen, once a numerous coastal plain bird which was also of limited abundance in the Piedmont Province areas of southeast Pennsylvania prior to its rapid decline during the first half of the nineteenth century.  In southern Lancaster County, the burned grasslands of the serpentine barrens in Fulton Township may have provided suitable Heath Hen habitat prior to the bird’s demise.  Curiously, Judge John J. Libhart did not note the Heath Hen in his enumeration of the birds of Lancaster County in either 1844 or 1869, indicating it was seriously imperiled or may have already been extirpated.

The Heath Hen (Tympanuchus cupido cupido) became extinct in 1932.  While the collection of this particular specimen had little significant impact on the population of this subspecies as a whole, prolonged hunting pressure was largely responsible for decimating the numbers of Heath Hens on the mainland of the Atlantic Coastal Plain.   According to the museum tag, this specimen was “probably taken in southern Lancaster County prior to 1850”, and was part of the collection belonging to the Linnaean Society of Lancaster City and County.  It is among hundreds of bird specimens on display in antique wood and glass cabinets in the North Museum.

The Heath Hen was extirpated from its entire Atlantic Coastal Plain mainland range by the mid-1860s.  The last remaining population was restricted to Martha’s Vineyard where, for the first time, a conservation effort was initiated to try to save a species.  After some promising rebounds, the Heath Hen’s recovery failed for a variety of reasons including: the population’s isolation on an island, severe winter storms, feral cat predation, and a flawed understanding of methods for conducting mosaic burns to maintain the bird’s scrub habitat and prevent large catastrophic fires.  A large fire in 1906 reduced the island population to just 80 birds, then there was a strong rebound to an estimated 2,000 birds (800 counted) by April, 1916.  One month later, a fire burned twenty percent of Martha’s Vineyard, striking while females were on the nest, and leaving mostly males as survivors.  A downward spiral in numbers followed for another decade.  Finally, from 1929 until his death in 1932, “Booming Ben”, the last Heath Hen, searched the island every spring for a mate that wasn’t there.

Based on life history and the morphology of specimens, the Heath Hen has long been considered to be a subspecies of the Greater Prairie Chicken (Tympanuchus cupido pinnatus), a bird of the tallgrass prairies.  However, for more than a decade now, modern DNA analysis has kept taxonomists busy reclassifying and reworking the “tree of life”.  For certain species, genetic discoveries often disqualify the long-trusted practice of determining a binomial name based on the visual appearance of specimens.  Molecular study is making Linnaean classification more scientific, and is gradually untangling a web of names that man has been weaving for 200 years, often with scant evidence, in an effort to better understand the world around him.  In the case of the Heath Hen, DNA research has thus far failed to conclusively determine its relationship to other species of prairie chickens.  The lack of a sufficient pool of genetic material, particularly from mainland Heath Hens, reduces the ability of researchers to draw conclusions on this group of birds.  There remains the possibility that the Heath Hen was genetically distinct from the Greater Prairie Chickens of the mid-western United States.  This would be bad news for organizations studying the possibility of introducing the latter into the former’s historic range as a restoration program.

The Carolina Parakeet (Conuropsis carolinensis) specimen on display at the North Museum was collected by John C. Jenkins in Nanchez, Mississippi in 1835.  The specimen was remounted by conservator H. Justin Roddy.

The last Carolina Parakeet (the only parrot species native to the eastern United States) died in captivity in the Cincinnati Zoo on February 21, 1918, one hundred years ago this past week.  It was a species inhabiting primarily the lowland forests of the southeastern United States

In Lancaster County, Judge John J. Libhart wrote of the species in 1869, “…Carolina Parrot, Accidental; a flock seen near Manheim by Mr. G. W. Hensel.”  Libhart did not mention the species in his earlier ornithological writings (1844).  Therefore, the Hensel sighting probably occurred sometime between 1844 and 1869.  The fate of a specimen reported to have been collected in the town of Willow Street sometime during the nineteenth century is unknown, the written details lack the date of its origin and other particulars that may clarify the authenticity of the sighting.

McKinley (1979) researched numerous historical sight records of Carolina Parakeets, but found no specimen from Lancaster County, or from Pennsylvania, New Jersey, Delaware, the District of Columbia, or Maryland to substantiate any of the reports in the Mid-Atlantic states.  In the days prior to high-speed photography, verification and documentation of the presence of an animal species relied on what seems today to be a brutal and excessive method of nature study, killing.  Lacking a specimen, the historical status of Carolina Parakeets in Pennsylvania, an area often considered to be within the bird’s former range, may be considered by many authorities to be hypothetical.

The Passenger Pigeon (Ectopistes migratorius) was abundant in the lower Susquehanna River valley through the early nineteenth century.  Specimens in the North Museum collection include colorful males in breeding plumage.  Several are from the original Linnaean Society of Lancaster City and County collection.

The Passenger Pigeon, too, has been extinct for more than a century.  In Lancaster County, Judge John J. Libhart listed the Passenger Pigeon by the common name “Wild Pigeon” and wrote of the species in 1869, “Migratory; spring and autumn; feeds on grain, oak and beach, mostly on berries; stragglers sometimes remain and breed in the county.”   There are numerous accounts of their precipitous decline both locally and throughout their former range, each illustrating the tragic loss of another portion of the North American natural legacy.

The North Museum specimen label describes the precipitous decline of the Passenger Pigeon in the lower Susquehanna River valley.

Martha, the last surviving Passenger Pigeon, died on September 1, 1914, in the Cincinnati Zoo.  Ironically, the last Carolina Parakeet would die in the same enclosure just three-and-one-half years later.  In the wild, the final three records of Passenger Pigeons were all of birds that were shot for taxidermy mounts in 1900, 1901, and 1902—an embarrassing human legacy.

By the early twentieth century, concerned citizens were beginning to realize the danger posed to many species of flora and fauna by man’s activities.  In the eastern United States, the vast forests had been logged, the wetlands drained, and the streams and rivers dammed.  Nearly all of the landscape had been altered in some way.  Animals were harvested with little concern for the sustenance of their populations.  Nearly unnoticed, the seemingly endless abundance and diversity of wildlife found in the early days of European colonization had dwindled critically.

In 1844, Judge John J. Libhart noted the “Log-Cock” among the birds found in Lancaster County.  Fortunately, he included the scientific name “Picus pileatus”, the binomial nomenclature then recognized for the Pileated Woodpecker (specimens to right) among taxonomists.  A record of “Log-Cock” could confuse researchers, leaving them to guess whether Libhart was referring to a woodpecker, a woodcock, a grouse, or any number of other birds including the long-extinct(?) Ivory-billed Woodpecker (Campephilus principalis).  Of the Pileated Woodpecker (Dryocopus pileatus today), Libhart wrote in 1869, “…now become rare and is only met with in old and extensive woods; breeds in the county.”  The Ivory-billed Woodpecker (specimen to left), a species of vast forests of large timber, living and dead, was restricted to the southeastern United States and Cuba.  Logging following the American Civil War and, to a lesser degree, shooting impacted both species detrimentally.  The Pileated Woodpecker recovered, the larger Ivory-billed Woodpecker, which has never been documented in the northeastern United States, has not.  These specimens are in the North Museum collection.

The movement to conserve and protect threatened species from relentless persecution owes its start to the Linnaean taxonomists, the specimen collectors who gave uniformly recognizable names to nearly all of North America’s plants and animals.  Significant too were John James Audubon and many others who used specimens as models to create accurate artwork which allowed scientists and citizens alike to learn to identify and name the living things they were seeing and, as time went by, not seeing.

Binomial nomenclature enabled the new conservationists to communicate accurately, reducing misunderstandings resulting from the use of many different names for one species or a shared name for multiple species.  Discussions on the status of Columba migratorius (the binomial name for Passenger Pigeon in the nineteenth century) could occur without using the confusing local names for the Passenger Pigeon such as Wood Pigeon or, here in Pennsylvania, Wild Pigeon, a term which could describe any number of free-ranging pigeon or dove species.  A binomial name, genus and species, makes the identity of a particular plant or animal, for lack of a more fitting term, specific.

Appreciation for the work completed by taxonomists who killed thousands of animals so each could be classified and assigned a name particular to its lineage is what finally motivated some to seek a cessation of the unchecked catastrophic killing of living things.  It’s the paradox of late nineteenth-century conservation.  The combined realization that a species is unique among other life-forms and that continuing to kill it for specimens, “style”, “sport”, or just an adrenaline thrill could eliminate it forever became an intolerable revelation.  The blood would be on the hands of an audacious mankind, and it was unthinkable.  Something had to be done.  Unfortunately for the Passenger Pigeon, the Carolina Parakeet, and the Heath Hen, help came too late.

SOURCES

Greenburg, Joel.  2014.  A Feathered River Across the Sky: The Passenger Pigeon’s Flight to Extinction.  Bloomsbury Publishing.  New York. 

Libhart, John J.  1844.  “Birds of Lancaster County”.  I. Daniel Rupp’s History of Lancaster County.  Gilbert Hills.  Lancaster, PA.

Libhart, John J.  1869.  “Ornithology”.  J. I. Mombert’s An Authentic History of Lancaster County.  J. E. Barr and Company.  Lancaster, PA.

McKinley, Daniel.  1979.  “History of the Carolina Parakeet in Pennsylvania, New Jersey, Delaware, Maryland, and the District of Columbia”.  Maryland Birdlife.  35(1):1-10.

Palkovacs, Eric P.; Oppenheimer, Adam J.; Gladyshev, Eugene; Toepfer, John E.; Amato, George; Chase, Thomas; Caccone, Adalgesia.  2004.  “Genetic Evaluation of a Proposed Introduction: The Case of the Greater Prairie Chicken and the Extinct Heath Hen”.  Molecular Ecology.  13(7):1759-1769.

Rathvon, S. S.  1866.  An Essay on the Origin of the Linnaean Society of Lancaster City and County, Its Objects and Progress.  Pearsol and Geist.  Lancaster, Pennsylvania.

Wheeler, Alfred G., Jr. and Miller, Gary L.  2006.  “Simon Snyder Rathvon: Popularizer of Agricultural Entomology in Mid-19th Century America”.  American Entomologist.  52(1):36-47.

Winpenny, Thomas R.  1990.  “The Triumphs and Anguish of a Self-Made Man: 19th Century Naturalist S. S. Rathvon”.  Pennsylvania History.  57(2):136-149.