Emerald Ash Borer Control in Connecticut

Published in April 2017 by The Connecticut Botanical Society P.O. Box 9004, New Haven, CT 06532   ~Established 1903 ~

The following  article was reviewed by Dr.  Claire Rutledge, in charge of Emerald Ash Borer Research at the Connecticut Agricultural Experiment Station (CAES) on 4-21-2017.  Written by Sigrun Gadwa, it was  edited by members of the CBS Conservation and Ecology Committee and the Cheshire Land Trust.

Will ash trees soon be just a fond memory?  The larvae of the iridescent Emerald Ash Borer(EAB) have killed over thirty million ash trees in the North America since it arrived from Asia in the early 1990’s in the Detroit, MI area.  Ash is an important tree of wetland and upland forests, farmland hedgerows, and urban neighborhoods.  Currently ash comprises 3 to 5% of our forests, but in some parts of the state it reaches 20% of the trees.  Ash is an attractive, spreading shade tree, and its wood is also very useful!  Ash  firewood is excellent; it seasons quickly, burns hot but slowly,  and is easy to split. The wood is also valuable as lumber and for woodworking, for example, durable, blond kitchen cabinets and the best and safest baseball bats.

The EAB  beetles feed on the inner bark (the phloem tissue). By gouging serpentine galleries, the borers disrupt the trees’ internal nutrient and water transport system. Trees die within 3-5 years. Once dieback in the canopy reaches 50 percent, the tree’s demise is certain, and there is no point in applying systemic insecticides, an option for control if done soon enough.

CAES and CBS  recommend ways to slow down this epidemic:     1) avoid transporting  ash firewood or lumber, if  bark is still on. 

And 2) It is also important to take down stricken trees, and properly treat the infested bark and branchesBeginning in mid-May, and through the early summer, the EAB beetles will transform from dormant pupae into emerald green, flying beetles, emerging from ash trees via tell-tale “D”-shaped exit holes. Taking down infested trees will prevent many EAB’s from flying off to other healthy ash trees, to lay the eggs for a new generation.

Biological control, fortunately, offers a reasonable expectation for success over the long term, against the Emerald Ash borer (Agrilus planipennis), a native to Asia. In 2013, under the direction of Dr. Claire Rutledge, the CT Agricultural Experiment Station (CAES), two tiny, Asian wasps (Oobius agrili and Tetrastichus planipennisi) were released in Connecticut and have been monitored for four years; Spathius agrili was released last year. These wasp species lay eggs on EAB eggs (Oobius) and larvae (Tetrastichus and Spathius), regardless of whether the ash species are American or Asian. The new crop of bio-control beetles emerges slightly before the EAB’s.   Oobius is very hard to detect, but the spread of Tetrastichus (shown below)  was documented, about 2.5 miles in two years, and it tolerates our climate. All the

tiny wasps meet a key criterion for any bio-control agent: host-specificity – they do not parasitize  native bark insects.   However, widespread establishment of these bio-control wasps is expected to take at least 10 more years.

Development of EAB-resistant strains of ash is also a slow process, but has a high expectation for success. The Asian species of ash are all resistant to EAB, and forestry researchers throughout the Northeastern US are working on breeding/locating resistant strains. David Yih, CBS President, asks anyone who finds a  surviving ash tree  in a hard-hit  area, to report it to CAES.StateEntomologist@ct.gov or 203-974-8474.  American ash species already have the potential to produce defensive phenolic compounds, that inhibit growth of EAB larvae. However, currently, most ash trees do not detect the burrowing EAB beetles, and therefore do not deploy their defenses – the missing link to EAB resistance.

“Slow down Ash Mortality” (SLAM)
Both Claire Rutledge and Douglas Emerthal of CTDEEP urge Connecticut citizens, institutions, and towns to take action to SLAM or “Slow down Ash Mortality” to give the biocontrol wasps more time to establish themselves, and for development of EAB-resistant ash strains.  These agencies are educating citizens on proper  disposal of the bark and wood, in order to kill the dormant pupae.  Chippers must grind the wood small enough to ensure EAB mortality:  no more than one-inch across, in at least two dimensions.

Before removing a tree, learn to identify it as an ash; if unsure, consult your local arborist or another expert. All ash (Fraxinus) species have opposite branching, compound leaves, and tightly ridged bark. Hickories, black oaks, and young cottonwoods have similar bark but alternate branching.  Identification resources include https://gobotany.newenglandwild.org and  and http://www.ct.gov/deep/lib/deep/forestry/eab/emerald _ash_borer_quick_reference_guide_final.pdf .

High woodpecker activity  is a tell-tale sign of EAB infestation, and is  somewhat helpful for slowing EAB spread. Look for long vertical streaks of exposed, sheared off, light tan bark, as shown below. Woodpeckers and nuthatches can consume  up to 85 percent of the EAB beetles in one tree, per a University of Chicago study – and their populations are growing in regions hit heavily by EAB. Helpful, but not enough.


If handled properly, use of EAB-infested ash trees for firewood, lumber, or woodworking seems – initially- like a thrifty alternative to huge piles of ash wood chip mulch. Wood of infested trees is still valuable for firewood or as lumber, after debarking, since beetle galleries are in the inner bark. The town of North Haven recouped $1500 recently, by selling ash lumber from infected street trees.

EAB beetles (and other wood insects) can be killed either  by debarking and chipping the bark, or by baking wood sections in a kiln. Wood with bark should only be transported and processed during the dormant season, October through March, although transport in any season  is risky.   Chunks of wood, bark, and debris on the truck bed, can shed EAB pre-pupae. Or EAB beetles can emerge while the wood is waiting for kiln treatment in a pile at a facility. Unfortunately, most tree removal companies do not debark on site, and very few Connecticut kilns are government-certified. The USDA requires a very high internal wood temperature of at least 60 degrees C (140 degrees F) for at least an hour.

One option for an industrious property-owner is to purchase a chain-saw mounted debarker on line and debark the logs of dying ash trees on site, using a tarp and chipping up the bark debris and branches.

Clean wood can safely be stored on site under cover, or sold, helping offset tree-felling costs. Even if you are unable to debark the tree, taking it down, chipping the smaller branches, and storing the rest under a tarp will significantly reduce the population of beetles emerging from the tree.

Our towns, and the state as a whole, need a non-wasteful, practical system for handling – and recycling – infested wood with negligible EAB dispersal, as well as more readily available debarking services and many more certified  kilns. On-line guidance is available for recycling paper, plastic, etc., but not for diseased trees.

Treatment with systemic insecticides is an alternative to control EAB, primarily for lightly infested, valuable tree specimens in an residential or urban area, though it’s also expensive and has significant downsides. To avoid killing pollinators that feed on the copious pollen produced by ash trees in early spring, the CAES guidance fact sheet recommends applying the product dinotefuran, after the ash bloom period, when the ash samaras (winged seeds) are starting to form, as pictured below.

Dinotofuran has a short-residual, in contrast to other more persistent, systemic insecticides like imidacloprid, clothianidin, and emamectin benzoate, which pose a long-term risk to many harmless insects, such as the inch worms that nesting birds feed to their young.  CAES is currently researching whether systemic insecticides may harm bio-control wasps. Broad-spectrum contact sprays are also a real environmental hazard, and may interfere with the spread of the  bio-control wasps; drift is often substantial, especially for a tall tree.   Note that heavily infested trees cannot be saved by insecticides. However, it seems wise to preserve  some ash trees with systemic, non-persistent insecticides in a very hard-hit area.  Their  seeds will be able to recolonize the area, once  the wasp bio-controls are well established.

In summary, CBS urges Connecticut residents to take down infested trees, using proper treatment of the inner bark, and to be alert for surviving ash saplings and trees. In part  so that trees with resistance to EAB may be detected, but also for the sake of the 100+ species of arthropods that have no other host plants – and the birds that feed on them – we do not favor widespread, proactive removal of healthy trees or widespread use of insecticides.  And finally, continued research, resistance breeding, and outreach by tax-funded agricultural extension and environmental agencies like CAES and CTDEEP are essential  if  ashes are to persist in the Connecticut landscape.  In the current political climate these organizations  are being targeted for  drastic budget cuts, so please let your state representatives and officials know how important this work is.

April 19, 2017  By Sigrun N. Gadwa, MS, for CBS.  Contact: sigrun.gadwa@sbcglobal.net

Photos by Peter Rzasa (EAB beetles), David Cappaert (Tetrastichus wasp) & Sigrun Gadwa (ash bark) or public domain.

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Where are the Starry Campions?



Silene stellata 
Starry Campion  (Silene stellata)   source:  www. ct- Botanical- Society.org 
 
In the 1960’s  on the north shore of Long Island, I recall seeing this exquisite native campion along hayfield edges, partly shaded by oak woods.  It grew both at Ships’ Hole Farm, where I grew up, and at Sweet Briar Farm, our neighbor to the west.    I have not seen this plant for many decades, either on Long Island or in Connecticut.  However, the bladder campion (Silene vulgaris) remains a common weed in fallow gardens and crop fields.    The photo below shows the genetic variant with a rose pink calyx.
Silene vulgaris

Bladder Campion (Silene vulgaris) source:  www. ct- Botanical- Society.org 

In Connecticut the number of extant populations of Silene stellata has shrunk to two,  and the species has been designated a Connecticut Species of Special Concern, though no scientists are currently studying the species, to the best of my knowledge.  The species decline is perplexing, as it  is still doing fine in many other states.

Lauren Brown failed to determine the cause, after exhaustive research and  thoughtful analysis,  though a preference for oak forest and partially sunny, well-drained conditions were confirmed.  (Brown, Lauren. 2003. Silene stellata (L.) Aiton f. (Starry Campion).   Conservation and Research Plan for New England.  New England Wild Flower Society,  Framingham,  Massachusetts, USA.)

Lauren Brown is a well-known Connecticut botanist and  a long-time, active member of the CT Botanical Society and the New England Wildflower Society.  For the Silene stellata project, she  scrutinized existing habitat records in manuals and herbariums,  and interviewed Connecticut’s most experienced botanists ,and several out-of-state nursery growers.  Botanist William Moorhead suspects the species needs higher levels of some soil minerals than are typically found in Connecticut glacial till, for two reasons. 1)  It has been found in it in traprock, limestone and shale soils, in the past, and 2)  it is more common in  the midwest, where soils have higher base-saturation. Nevertheless, there are also records of the plant growing in sandy, acidic, mineral-poor soil – including the population at Ships Hole Farm.  I was struck by one out-of-state nursery growers’ comments that seeds from different collections behaved very differently.  Some growers noticed widespread self-seeding, others observed no self-seeding what-so-ever.

This makes me wonder whether isolated  populations – including those in Connecticut –  may have only a portion of the species total gene pool, for traits related to reproduction. 
In this case, could cross-breeding with several populations from other nearby states solve the problem?  This is a more mundane solution than gene pool repair using ancient genes, as discussed in a recent article by M. Stone:  
After Thousands of Years,  Earth’s Life Forms are taking off. “  The links for the whole article:    http://gizmodo.com/after-thousands-of-years-earths-frozen-life-forms-are-1686782409

After Thousands of Years, Earth's Frozen Life Forms Are Waking Up

Formerly extinct Siberian campion  (Silene stenopylla)   Source:   M. Stone’s article, 2015, citation above.

It is amazing that a Silene (campion) seed from Siberia, 32,000 years old, actually germinated and bloomed in 2012! The symmetrical flower is quite recognizable, with its five deeply notched petals.  If asked to identify it, I’d have turned right away to the campion section of the Pink family (Caryophyllaceae), in one of my botany manuals. 

This ancient campion population has been found to have genes related to reproduction and flower morphology that have been lost from the modern counterpart of Silene stenopylla.  Gene pool restoration of the modern Siberian Silene species is now being contemplated. 

A similar genetic rescue is actually in progress, for the genetically-impaired black-footed ferret, using genetic material from preserved tissue – an example of a “benign” GMO (genetically modified organism). This midwestern “top predator” narrowly escaped extinction, when 99% of it’s main prey, the prairie dog, were eliminated to make room for crops. After the bottleneck, the residual ferret population lacks the genetic diversity to survive, long term. 
Researchers are optimistic that the black-footed ferret’s  gene pool will recover.


After Thousands of Years, Earth's Frozen Life Forms Are Waking UpBlack-footed ferret
 Source:   M. Stone’s article, 2015, citation above.

Thinking back to Silene stellata, its continuing decline may also be caused by  caused by genetically depauperate, fragmented populations,  in intensively developed parts of Connecticut and New York state, with few remaining farms.  If this is the case,  there is no need to undertake extremely expensive gene-splicing, using ancient genetic material! The more mundane technique of plant breeding with out-of state populations would suffice. 

However, informal interbreeding at nurseries could also disrupt or swamp existing, balanced genetic systems. Precarious Silene stellata populations in Connecticut  – and probably Long Island as well – warrant systematic analysis directed by scientists with expertise in genetics as well as plant ecology and plant breeding.    Seeds and data can readily be collected by volunteers, as this wild flower is very easy to identify, unlikely to be  confused with bladder campion.  It is also pretty enough to provide motivation.  Perhaps the species is in fact much less rare than we think – just under-reported.  This is often the case.  Plant-oriented groups like CT Botanical and The Hardy Plant Society could be queried. Herbivory by deer and soil mineral deficiencies also need to be ruled out as  factors responsible for the decline.  However,  gene pool enhancement,   if that is indeed what is needed, must be very carefully executed by professionals. 

T
he pro-active way to prevent genetic bottlenecks and keep to keep plants and creatures off that rare species list, is through the ongoing actions of land use boards,  town selectmen, and land trusts., to maintain habitat connectivity and sizable habitat blocks for ecological communities.  To be genetically connected, starry campion populations need to be  within  pollinator-foraging range. For a large mammalian predator,  like a black-footed ferret, suitable habitat (prairie dog villages) can likely be dozens of miles apart, but not several hundreds. 

Silene stellata

Starry Campion  (Silene stellata)    source:  www. ct- Botanical- Society.org 

by  Sigrun N. Gadwa, MS, PWS

 

 

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Lesser Celandine – a Temptress

DSC04320When lesser celandine (Ranunculus ficaria) came up in a shady moist part of my yard, I admit, I did not promptly rip it out, though I do know it is a confirmed Invasive Plant Species, on the official Connecticut List.  I realized that this patch  probably originated  from a bulblet that I had tracked back from the floodplain after field work, likely stuck in a boot tread.

Its glossy, yellow petals were  like those of a buttercup or marsh marigold, only there were more of them (eight versus five).   The  dark-green,  scalloped  leaves were shiny and heart-shaped, and formed a full,  weed-free ground-cover, though spreading far less  than the patches I had seen on the Quinnipiac River and Wharton Brook floodplains.  I rationalized that this species  was invasive in wetlands, not upland yards, so… I might as well let it grow and study it. When seed set  failed altogether, I was reassured that seeds could not disperse to the Ten Mile River floodplain, only half a mile away.  As a spring ephemeral, the lesser celandine  dwindled as the tree canopy expanded, and by August I saw only a few yellowed leaves- and many bulblets. I erected a barrier of logs and brush  so no one would walk there and pick up bulblets in their shoes.

Ranunculus ficaria  spreads aggressively by bulblets in river floodplains, where floodwaters move the buoyant bulbs around, but   I had rationalized that my patch  was innocuous as a small sterile clone in an inland, upland setting.  Two years later, my friend Jeanne Chesanow showed me a similar, small sterile patch of lesser celandine in her yard, also  in shaded, mesic upland soil. She lives about  a mile south of my house. I started to wonder, just how far do bees fly?

Lesser Celandine is reported to produce fertile seed erratically. Seeds may not have not formed in my and Jeanne’s  clones because the female flowers must receive pollen from a genetically different mating type, and none grow nearby.  However, with cross pollination between lesser celandine patches in multiple gardens, how soon will a threshold of abundance be reached, such that lesser celandine starts setting more viable seed? If that happens, will this plant “take off”  in mesic, upland habitats, as well as river floodplains?  Purple loosestrife spent many decades in the twentieth century, as a well behaved  garden plant,  producing few fertile seeds…. until that abundance threshold was reached and self incompatibility was no longer limiting. Only then did it start proliferating in a wide range of wetland and moist habitats.

This is a particularly tempting invasive, the more so because it forms a natural, attractive ground cover, and  is hardy and carefree. It is widely sold!  Most gardeners are probably unaware they are harboring an invasive species, may think it is Marsh Marigold (Caltha palustris).  I  wondered, just how many other yards in Cheshire also have celandine patches.  It was time to stop playing around. I dumped a thick layer of mulch over my patch, and Jeanne got rid of hers as well.  Digging it is risky, as bulblets are dispersed.

A year has passed, and it is early spring, mud season. My garden has no yellow celandine flowers. As a weekly erosion inspector at a school construction site,  I am trying to persuade the contractor to spread hay over the idle bare soil, to reduce the export of fine sediment and phosphorus to the Quinnipiac River.  I wonder, could the yellow-dotted carpets of Celandine over bare, floodplain soils actually benefit the river and Long Island Sound, by reducing phosphorus  loading to during the early spring season?   DSC09978ClaytoniaHowever, especially in moist floodplain habitats, large mats of lesser celandine obliterate other  delicate spring ephemeral  wild- flowers like trout lily, wild ginger,  and spring beauty, and  also compete with perennial sedges and spring-germinating annuals.

However, lesser celandine  is reported to be much less less invasive in uplands than floodplains. Could this plant  be useful as a spring ground cover for landscaping, in well-drained soils, until other garden perennials  have reached summer biomass?    Could it help reduce lawn areas and turf chemical use, to protect downstream water quality?  More funding is needed for applied research,  to more precisely understand which habitats are most vulnerable to a given invasive species, and also to study breeding systems.  Is increased production of fertile Lesser Celandine seed really a threat?

Ranunculus ficaria Long Isalnd

 

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Mugwort’s Milestones

Mugwort or wild chrysanthemum (Artemisia vulgaris) has reached two unfortunate milestones: it has been added to the official, confirmed invasive species list of Connecticut, and it has started producing fertile seeds! It used to spread only by rhizomes, via stray chunks of dirt carried by tires & equipment. (That is what the internet fact sheets say.) But no longer, per recent germination tests by Jeff Ward, a scientist at the New Haven campus of the Connecticut Agricultural Experiment  Station.

Mugwort was probably an obligate out-crosser, needing to be pollinated by another genetically different individual. Over the past few decades, populations have grown and spread,  mostly along roads and in construction sites. Mugwort may have evolved to be able to self-pollinate.  Or it may simply be that more  unrelated clones  grow closer together, such that successful cross-pollination (by wind) has started happening more often.  Mugwort is now  “taking off.” Unless the herbal medicine entrepreneurs start harvesting in quantity!

Chrysanthemum's Ugly Cousin

Chrysanthemum’s Ugly Cousin

It does look rather like a chrysanthemum.   As a young gardener I made that error, and let several grow through the summer. But the flowers were tiny and totally nondescript, not lovely mums!

In winter mugwort stands are dull, even, light brown, and they  usually cover large areas.  Patches spring up on bare soil, left idle and unplanted, unstabilized after road-widening, topsoil stripping, or whatever. Incidentally, not stabilizing exposed soil at a work site, after active work has ceased, is counter to the 2000 Connecticut Erosion  Control manual. If the road crew would only spread a few bales of mulch, preferably non-weed-free cuttings from  a local meadow.

Dull brown in Winter

Dull brown in Winter

One cannot rationalize that at least the wildlife value is high.  Flowers are pollinated by wind, not bees or butterflies. Mugwort seeds are so tiny that the effort of finding and eating them would be greater for a songbird or vole than the calories gained. Most of the seed is its pale flying scale, irregular and variably shaped.

An aroma like a  potent disinfectant

An aroma like a potent disinfectant

A potent aroma will strike you as you walk though a mugwort patch in November, and crunch up some crisp leaves and seed heads – I imagine it smells like a busy apothecary  in the 19th century. It was used to repel moths in wool closets. Powdered dried mugwort is still  fed to sheep and goats, to prevent and treat parasites. Mugwort is sold on the internet to treat various human ailments.

Sheep farmers beware! Toxic overdose is possible, as plants vary widely in active ingredient concentrations. On the other hand, if you can determine the approximate  potency of  your local Artemisia vulgaris, using it to control parasites will help help you get a better price for meat and wool, as “certified organic”.

In contrast to mugwort, chocolate vine (Akebia quinata ) could hardly be more appealing, even has a fragrance of chocolate. It it is Akebia_quinataa special, uncommon ornamental that has NOT yet reached the stage of fertile seeds, though it sometimes escapes and smothers an acre or two of woods.  At a challenging restoration site in the wealthy town of Wilton, Connecticut the diameter of  Akebia patch diameter increased from 10′ to 40′ in two years, and the vine has now climbed at least 15′ up 8 trees and saplings.

It used to be a an uncommon, fancy horticultural specialty, but is now  sold over the internet (catalogue is source of photo) with alluring pictures. Construction equipment and roadside disturbance were the major players in the initial build-up of mugwort.   If Akebia becomes a “kudzu of the north”, its intrinsic beauty will be responsible. I fear the “fertile seeds ” milestone may  not be far away. For now we are grateful that Connecticut plants are sterile. 



 

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Critical Habitats in Connecticut

Introduction

Ebony spleenwort, characteristic of rocky ridgetop critical habitats, regardless of the type of bedrock.

I am often asked, just what is a critical habitat, and is it protected or not?   My answer is drawn from  a hybrid  DEEP document  (map plus explanations and keys)  called “Critical Habitats” last revised in 2011.  Recently retired DEEP plant ecologist,  Kenneth Metzler wrote: “these habitat types have a long history of conservation interest and have been documented and studied as being among the most rare, unique, and threatened, habitats in the state.”    Critical habitats support uncommon ecological communities, because their geology, soils, and/or hydrology are distinctive, which also confers scientific, educational and heritage value.  They each  support a characteristic and unique suite of plant and animal species.   25  upland critical habitats were  identified in the Connecticut Comprehensive Wildlife Conservation Strategy (CWCS)The intent of the DEEP document is to help towns with their conservation planning –  not to ban development  of all critical habitats,  but  as a planning tool, to prioritize open space protection initiatives, in conjunction with other conservation planning principles:  minimize habitat fragmentation, and maximize the size and ecological integrity of protected tracts. www.cteco.uconn.edu is the URL.

State statute does include protections for endangered and threatened species. Critical habitats are a good deal  more likely than the average field or woodlot to include state-listed species (Endangered, Threatened, and Species of Special Concern.)   Each critical habitat also has many other unusual plants and animals that don’t quite “make the cut” for  Connecticut’s List – pitcher plant in a Black Spruce Bog, for example.

Also expected in a critical habitat are rare species among the understudied life forms like lichens, mosses, and soil microbes.  These life forms are simply missing from the Connecticut Natural Diversity Database (NDDB) lists.

 Potential rare species are likely to be missed by a targeted search for one or two species, especially because they are readily detected during a  short window. Plant seeds may lie dormant in the seed bank, sprouting only in certain years.   Many small plants are usually overlooked, even by botanists, except during a brief window when they are in bloom. Most insects, including butterflies and moths, are detectable only for a brief portion of the year. Rather than doing exhaustive, specialized  searches, it is less expensive and simpler, to determine whether the expected suite of diverse, characteristic plant species is present, and if it is, to protect the critical habitat.

For example, we  assessed a pristine black spruce/white cedar/ sphagnum bog recently, with hundreds of pitcher plants.  The targeted listed species are insects that feed on pitcher plant; we are recommending conservation of the whole bog with a wide buffer, with no need for a search for the tiny rare insects.

A bog in Canterbury has 100’s of of pitcher plants, and land use boards fully understand that this critical habitat, and must be fully protected.; the biodiversity value of rocky outcrops is less widely understood.

 

Bedrock outcrop in Essex. A full inventory of the hilltop plant community is not possible outside the growing season. We recommended including  the entire hilltop  in the  open space portion of the subdivision.

 

Planning Considerations

The “critical habitat” label is a flag for land use planners  to commission  a thorough inventory and to search for rare, state-listed  species in multiple seasons, before the area  is developed, and if possible over a several year period.  Critical habitat status alerts planning boards  that a property  is likely to be a desirable, interesting  destination for recreation,  and a potential site for nature study and/or scientific investigations.   Trails, towers, boardwalks, maps, and informative web sites can enhance these human values.  Excessive human use may degrade them, but more often they are protected by human intervention,  such as invasive plant  control or occasional tree-trimming to maintain an open critical habitat.  Public education on a critical habitat helps with its long term protection.

Some critical habitats, like black spruce bogs and white cedar swamps,  are so  unusual that their  status is widely understood and accepted, and they also have the  protection of being wetlands. The special status of other critical habitats is much less widely understood.  As a botanist, I am most familiar with three largely overlooked critical habitats:

1)  The group of plant communities on soils derived from traprock or  limestone (subacidic/neutral and  mineral-rich),   including  glades, dry forests, and summit shrublands;  and

2) Outcroppings, ledges, cliffs, and rocky, open  summits, with pockets of mineral-rich soil.  These are defined as critical habitats in the ECO key, regardless of bedrock type.

3) The rich floodplains of larger rivers;

The status of these less well known critical habitats is not widely understood by regulators, natural resource professionals, and the general public; as explained above,  official DEEP Critical Habitat status does not confer protection from development or quarrying, unless the areas are demonstrated  to support Endangered or Threatened species.  However, CTDEEP typically requires a survey for rare species by an expert, if a development site includes a known critical habitat.  Floodplains are protected, but the main reason is avoidance of flood damage.  Protection for privately owned rocky knolls and summits is still lacking in most town zoning regulations, despite official DEEP Critical Habitat status.

For the volcanic traprock ridges and certain ridges with amphibolite minerals, there exists already a model ridgeline protection ordinance, based on a CT Statute (Sections 8-1aa and  8-2 c), incorporated into the zoning regulations of some towns.  This ordinance applies only to the more  dramatic, high ridges, though low ridges, if reasonably undegraded by man, also include critical habitats with characteristic and unusual traprock  geology, botany, and fauna.

Zoning regulations can also be amended  to protect better natural features meeting certain criteria with value for the community as a whole:  heritage value, outstanding aesthetics,  or  historic, scientific, and/or educational interest.  Protection of these natural features  can also be a goal guiding open space acquisition activities by municipalities, the state, and private land trusts.  However, consistent with the Connecticut Comprehensive Wildlife Strategy, the long term welfare of the fauna and flora will better served by one sizable (e.g. over 100 acres) preserve with a few critical habitat pockets, than by multiple critical habitat pockets (rock outcrops) in a matrix of small woodlots and development.

History of the “Critical Habitat:  Concept

DEEP has been refining its list of “Critical Habitats,” for many years, building off those identified by Joseph Dowhan and Bob Craig in Rare and Endangered Species of Connecticut and their Habitats (1976), with descriptions of all of the State’s Ecoregions (DEEP Natural Resources Center  Report of Investigations No. 6.)  My associate, George, and I have referred to this red book so much in our ecological consulting work, that both our copies are tattered.

For over a decade, natural resource professionals cited the List of 13 Imperiled Habitats developed by Ken Metzler of CTDEEP and David Wagner of the University of Connecticut at Storrs.  It includes one difficult-to-map habitat:  “headwaters springs and seeps”   that is not on the current DEEP critical habitat map key, although it is a fragile habitat for multiple rare and uncommon species, and crucial for the health of larger streams and rivers.  Better consistency is needed between the Imperiled Habitats List and the new CT ECO document.

The current CT ECO  (Connecticut Environmental Conditions On-line) classification system  includes a map showing the larger critical habitat units, and also a key with detailed  definitions of each critical habitat. Since the scale of the map is such that most occurrences are omitted and since much of the state has not yet been surveyed, the introduction and the key are  actually the most important parts of the document.  

A fine introduction  is Dr. Robert Craig’s  book Great Day Trips to Connecticut Critical Habitats (2004),  which is available, used, on line.  This readable book is a guide to actual examples of fascinating critical habitats, accessible to the general pubic, with much thoughtful, scientific explanation.    Foremost a bird expert, Bob Craig  now runs  Bird Conservation Research, Inc., a non-profit in Eastern Connecticut.  I knew him twenty years ago  in grad school at the University of Connecticut at Storrs.

Scale Considerations

The group of critical habitats  associated with The Metacomet  traprock ridges occupies a tiny fraction of the state of Connecticut, but is nevertheless  extensive enough to support large metapopulations of both common and uncommon plants and animals.   The river floodplain habitats are  include  unusually large critical habitats, ecologically and genetically linked by flowing water.

I keep encountering morphologically distinctive plant varieties in these critical habitats, and realize that genetic variability also encompasses unseen metabolic characteristics, that will help plants adapt to ecological change. A  gene pool with hundreds or preferably thousands of individuals is needed for a good prognosis for long term survival in the face of climate change and other disturbances.

Horticultural and landscaping potential and even potential for medicinal use are other reasons to preserve the botanical biodiversity in critical habitats.  For example, the  smooth aster variety shown below (Symphiotrichum laevis)  is  bushy & colorful, and tolerates a dry, rocky site on West Peak of Meriden’s Hanging Hills. It is a lovely and ornamental perennial wildflower, and would be well suited to xeriscaping.

Impressive data for many traprock taxa has been collected as part of development applications,  such as  the gas plant application on Cathole Mountain  in 1999. The Connecticut Botanical Society and the local bird clubs have  long term data from many field trips to subacidic and rocky  critical habitats.

Glade habitat on West Peak of the Hanging Hills, in Meriden, June 2011. The grassy “lawn” is Pennsylvania sedge, and the flower is smooth rock cress, the food for the caterpillar of the endangered orange falcate butterfly. Hop hornbean, a typical glade tree, of subacidic, mineral-rich soils, at left. A talus slope is in the background.

The complex of critical habitats on the Metacomet traprock ridges has large populations of characteristic species like ebony spleenwort, bottlebrush grass, dwarf saxifrage, and hop hornbeam.  They are not Endangered or Threatened species, protected by state statute,  but are still species that are scarce  in the surrounding, fragmented suburban landscape.  Other species like Eastern box turtle and Ribbon snake,  are listed as Species of Special Concern,  such that CTDEEP can require searches and management plans, but  cannot prohibit habitat development.  Similarly clusters of crystalline bedrock outcrops in several sizable forested tracts along the Connecticut coast (including “The Preserve”  in Essex and Old Saybrook) also support robust populations of Special Concern reptiles,   and metapopulations of  uncommon, rocky-site  plant species like smooth foxglove and orange-fruited horse gentian.  Along river floodplains, flowing water and waterfowl  disperse seeds and link small stands of rare and uncommon plants, like  Davis’ sedge,  into larger genetic metapopulations.

For some taxa, a critical habitat need not be large and continuous so long as other examples are within dispersal distances for  seeds, pollen, moths,   etc.  Such a parcel of critical habitat is still part of the overall unit, from a genetic standpoint. The on-line CT ECO map includes the large, contiguous well-known examples of critical habitats.  Many other smaller examples are also worthy of study and protection, if they have not been severely degraded by invasive species or past farming.

Critical Habitats  that lie within a much larger matrix of natural habitat are especially valuable from an overall  wildlife conservation standpoint, especially for forest birds, large mammals,  and for vernal pool amphibians. Example are the summits of Connecticut’s  northwest hills;  the extensive rugged forests with many bedrock outcrops in the undeveloped parts of Essex and Old Saybrook; and Cathole Mountain; and the Silvio Conte wildlife Refuge along the Connecticut River.   The lower forested slopes of traprock and limestone ridges are not critical habitats,  but they greatly increase the width and size of the habitat blocks.  They also help protect the critical habitats along the ridge lines from colonization by invasive plant species.  For example, the large, latent Summerlin Trails residential project on Cathole Mountain, as initially conceived, would avoid the upper ridge crests and critical habitat areas, but would much reduce the size of the overall habitat block,  with potential to harm  vernal pool species and area-sensitive  forest bird populations.

Potential Outreach

Ample interesting material is available for outreach on critical habitats.  A newspaper article or radio program could use examples  of success stories,  like Hubbard Park in Meriden and Quinnipiac State Park along  the floo0dplain of the Quinnipiac River;  of dramatic battles, like that over development of a  pristine section of Cathole Ridge off Kensington Road in Berlin and of Cedar Ridge in Newington with outcome still unclear;  and of destruction  like the  mined section of Corporate Ridge in Rocky Hill.  Media outreach could revisit the volcanic geologic history, and past dramas, like the story of the now-defunct gas powered plant on Cathole Mountain in Meriden.  It could remind the public and the land use boards of the successful campaign, led by Norm Zimmer in the 1990’s,  for a Ridge Protection Compact.

 

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Rich and Poor in the Plant World – Part 1

Red columbine grows in mineral -rich soil on rocky outcroppings. This thriving population was identified in Rocky Hill, at a site to become a shopping center. The plan was adjusted to preserve most of the knoll, not grade it away.

My much-loved,  old, heavy botanical manuals (e.g. Fernald and Britton and Brown)  always include a sentence or two about the habitat where a plant is found, as well as exceedingly detailed morphological descriptions.  “Found in rich soil” is a frequent description that can apply to fallow farmland, alluvial  floodplains, a bouldery forest at the base of a hillside,  or  a rocky summit with two inches of mineral-rich soil , covered with red columbines.  I used to think rich soil was rich soil, no matter where it was, with other ecological factors making the plant communities so different from each other. But I’ve learned that is only partly true.

Fallow Farm

A fallow, fertile crop field supports a rank stand of annual weeds like pigweed, ragweed, and giant foxtail, that have the genetic capacity to grow tall in response to high levels of  the three basic nutrients (especially nitrogen, but also phosphorus, and potassium).  The field produces abundant birdfood, but  weed competition excludes all the wildflowers and ferns than are genetically programmed to stay short for their whole lives. Frequent plowing  also excludes native perennials.  Soils may or may not be “rich” in ninerals like magnesium and calcium.  The probability of finding rare species is very low.

Floodplain

The dominant understory vegetation in a “rich” floodplain of a large river is also thick and lush, mostly annuals like jewelweed and false nettle, though flooding and ice, not plowing excludes perennials.  Frequent deposits of fresh silt and organic matter provide an abundant supply of the three, basic common  nutrients. Especially if the watershed has traprock ridges, alluvial soil is also rich in other minerals like calcium, magnesium, and manganese, and subacidic.

Such  soil is well-suited to late-season farming.   It also can support uncommon, minerotrophic (mineral-loving)  plants, where growing space and light is available. Floodplain annuals start growing only after floodwaters  recede, and tree falls and thick deposits of sediment often  open up new bare soil patches.

Jewelweed is dominant in alluvial soil with shale gravel, along Stocking Brook , in southwestern Berlin, Connecticut.

I have found delicate wildflowers only in early spring, before they are shaded by the rank annuals.  Dutchman’s Breeches (Dicentra cucullaria)  and spring beauty (Claytonia virginica) do grow on the banks of the Farmington River in Simsbury, with much traprock in its watershed. I also know a few rare floodplain sedges, like Davis sedge (Carex davisii),  with a vigorous,  tall growth form,  that can compete with the dense floodplain annuals – though not invasive shrubs like Euonymus alata.  Do  these uncommon floodplain plants need soil with high concentrations of minerals, with or without high availability of nitrogen, phosphorus and potassium?  Has any  research on this been published?

Base of a hillside

Another  place to find  “rich site” wildflowers, ferns  and sedges  in Connecticut is  the base of  a  hillside, among the boulders. Soil water at the base of a hill has been seeping slowly  downhill for hundreds of feet,and for many centuries,  dissolving minerals from the surfaces of soil particles and rocks. Topsoil has  also slowly washed downhill over the centuries. Slope-base soil  typically  has ample minerals and enough of the three basic nutrients, and is moist as well.  Stately bottomland trees grow in this rich, rocky soil:  sugar maple, red oak,  tulip poplar,  ironwood, and occasional basswood.   Spring ephemerals like red trillium (Trillium erectum) , bloodroot,  and trout lily  (Erythronium americanum) do most of their growing  before the trees leaf out.  However, some shade-tolerant minerotrophic plants  can keep growing  through the summer, like red elderberry and  broad beech fern – and other much rarer ones, like Goldie’s fern (which I have yet to find.)   The  understory is  less dense than in the floodplain, with less competition, and greater diversity. It still rankles me that a Target big box store was built  in this habitat at the base of a Meriden traprock cliff, without any ecological survey beforehand. It was over ten years ago, but I still boycott the store!

At the base of very long  seepage hillsides, soil water has the highest mineral concentrations,  and the slope-base plant community is potentially most diverse. The reason is simple, as I was taught by my major professor Ton Damman: the further the groundwater travels, the more minerals are dissolved.  I  recall an amazingly diverse  swamp at the base of a great hill in Winsted, Connecticut, west of Route 8.  We measured the nitrogen  levels, and they were quite low. Vegetation was low in density and stature, however, not a rank, impenetrable  thicket.  This allowed diverse, minerotrophic plants to coexist, including  melicgrass (Glyceria melicaria), chestnut sedge (Carex brunnensis), and a dwarf raspberry called Rubus pubescens.

Rocky Outcroppings

This year I  found these same plant species – and also Dutchman’s breeches  – on several  shale outcrops  in the  East Berlin geologic formation.  The laminated  shale rock structure increases surface area available for mineral dissolution. Positively charged cations (e.g. calcium and magnesium)  enter the soil water and increase the pH.  Subacidic soils derived from traprock, limestone, or shale  have the highest mineral levels, and  support diverse and interesting  plant communities.  Minerotrophic   plants are most likely in areas with subacidic soils, in large part because higher pH makes minerals more available to plants.  (This is the reason that farmers apply lime.)

Brittle fern, an uncommon minerotrophic species of rocky habitats is growing out of a shale rock face along an incised stream , Stocking Brook in Berlin, Connecticut.

Characteristic plant species, uncommon  in other habitats, as well as truly rare, state-listed species,   are also often associated with  ledges, outcroppings, and  crevices of  rock formations, regardless of bedrock type. Botanizing is always rewarding in such habitats! I often find red columbine (Aquilegia canadensis) on traprock summits,  but sometimes also in areas with  a metamorphic  outcrop of gneiss or schist.     Dwarf saxifrage, Dutchman’s Breeches, Canada moonseed (Menispermum canadense), and red elderberry (Sambucus racemosa), and brittle fern  grow at the base of a low traprock cliff  near Kensington Road in Berlin.  The first four species I  often see in  undisturbed trap habitats, but rarely elsewhere.  The brittlefern (Cystopteris  fragilis) is rarer, but less tied to traprock.  The only orange-fruited horse gentian (Triosteum aurantiacum)   I have ever seen was at the base  of  a sandstone shale rock face, but they have also been found on coastal bedrock outcrops in Branford.  Rare prickly pears  (Opuntia humifusa) have been found in Old Saybrook on bedrock outcrops on “The Preserve” property; this is  probably because the open, southern exposure mimics the warmer growing conditions at the center of its range., and may – or may not – be also related to mineral-rich soil.

Seedling of a Canada moonseed vine, in moist, rich soil at the base of a basalt rock face; north end of Cathole Mountain, Kensington Road, Berlin.

 

Questions

The term minerotrophic is widely used, but solid data is lacking as to exactly which minerals are needed by which plant species, and at what levels.  What are the relative roles of microclimate and soil mineral needs, as they affect plant  distributions on rocky summits and outcrops?    How often is the distribution of a “rich site”  species limited, not by soil composition, but rather  by competition with other plants?   Many  uncommon plants are known to be characteristic of rocky habitats.  How often is this  due to the role of rocks and boulders in reducing competition, rather than mineral availability?  To what extent are “rich site” plants found along slope bases or on “rocky site” plants on summits because  the areas were historically too bouldery for farming, so that the plants remain there, but were long since eliminated elsewhere by  agriculture?   A telling comparison is the nearly pristine, and botanically diverse, forested  north slope of the traprock ridge at Dinosaur State Park, versus the depauperate east slope, which has been farmed for over a century.  Parts of this this field  are  infested by invasive Japanese barberry and burning bush, and the dominant ground cover is the prickly dewberry, a very common dry-site plant.  But even this field, also supports populations of uncommon plants  like Carolina rose and panicled bush clover, growing in sweet (subacidic), mineral-rich soil with traprock near the surface.

These are opportunities  for interesting ecological research!  We really have not advanced very much past the “rich site”  or “rocky site”  habitat  characterizations in the old botany manuals.

 

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Transplanting Soil Blocks, a Biodiversity Rescue Tool

Several other state-wide rare plants are common in this former cranberry bog.

This past Spring (May and June 2012) a group in south central Connecticut transplanted many blocks of peat soil, about 20″ X 20″, with very rare Adder’s Tongue Fern (Ophioglossum pusillum).  This is  an attempt to salvage the population from an area that is to become an active cranberry bog again, after many years of lying fallow except for mowing. The soil and vegetation blocks also contained the rest of the ecological community:  royal fern, assorted sedges, rushes, and wildflowers, countless microorganisms,  invertebrates,  and –  not to be forgotten –  a seed bank. Watering and monitoring continues.

The destination area was  closer to the road, also former cranberry bog, but still fallow. When choosing a location to place a block, great care was taken to replicate hydrology and aspect, though peat depth could not be replicated; the organic horizon was substantially deeper in the source area.  It took over 100 man-hours of back-breaking labor by Carol Lemmon, a Board Member of the Connecticut Botanical Society,   and half a dozen others (mostly volunteers)  to move the population from the future cranberry cultivation area.

Maintaining the former cranberry bog as a wet meadow, rather than letting it revert to a red maple forest, requires regular  mowing.  Meadow, as a wildlife habitat, is in much shorter supply in Connecticut than forest.  Phragmites australis control was also needed. This invasive would have completely overrun the entire diverse botanical community without expensive eradication. Fortunately with multiple rare and uncommon species, including several species of gorgeous  pink orchids, funds have been found for  the aspects of rescue, maintenance,  and restoration  that need paid skilled workers.  The biodiversty and beauty of the unusual peatland wet meadow  motivate volunteers to  donate  most of the man and woman power for execution of the rescue operation, as well as restoration and ongoing maintenance.

The Connecticut Threatened Adder’s Tongue has a simple, ovate leaf with a pointed tip, entire leaf edges (no teeth,) and is only abut two inches long.  Its flower is a plain green spike, rather like a plantain flower. Adder’s Tongue looks for all the world like a Canada Mayflower leaf with a plantain flower.  The photos below include  a transplanted block with a few such leaves.  For a clearer image, just google the scientific name. Blooming Pitcher Plant and some Rose Pogonia orchids are also shown.

I apologize for not including the location of this worthy project, quite likely to succeed, but it is CTDEEP policy not to divulge locations of rare species, for their future safety.

Ambitious rescue operation for one of the last populations of a Connecticut-Threatened plant species

A population of CT Threatened Adder's Tongue was transplanted, soil block by soil block into this wet meadow, from another nearby boggy wet meadow, soon to become a commercial cranberry bog again.

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Trace Minerals & Toxins: GMO Concerns

Why does food grown organically seem to taste better than conventionally grown food. Is this my imagination or due to some real difference? I read that levels of trace minerals (micro-nutrients) were usually lower in non-organic food. This makes sense for hydroponic foods, but why should conventional agribusiness crops have lover levels of trace minerals?

Truthfully, I’ve been somewhat sceptical about health and safety risks from GMO (genetically modified organism) crops? Inserting genes for disease resistance does seem sensible. The Environment Committee of the Connecticut Legislature happens to be reviewing a bill (HB 5117) that would require labeling all such food, so I read Hearing testimony and did some research.

A recognized concern, from a health and environmental standpoint, is the gene that has been spliced into crop plants, for a persistent bacterial toxin (from BT or Bacillus thuringensis). This toxin is now found in the blood of the majority of American women. It is a natural pesticide that attacks cell membranes – not just in the target pest caterpillars, but also membranes in rats and potentially in humans, especially fetuses. However, I did not see any data on toxin concentrations, and information on threshold concentrations for harmful effects is sorely lacking.

Analysis of potential impacts on adjacent ecosystem biodiversity from BT GMO crops has also been wholly inadequate. How will populations of economically insignificant species of caterpillars, moths and butterflies -and their predators- be affected by feeding on leaves and pollen from GMO plants along field edges? Ill effects on migrating monarch butterflies were in the news last year.

I see even less less public concern with the largest category of GMO crops: those with an inserted gene that makes them “Roundup Ready”, able to tolerate its active herbicide ingredient, glyphosate, although application rates must be cranked up several fold. Interference with uptake of micro-nutrients by glyphosate was studied in Stuttgart, Germany, at the University of Hohenheim, over ten years ago. German researchers warned us that mineral-deficient plants would be more susceptible to soil fungal diseases; this is now well documented for many fungal diseases – most recently widespread Fusarium wilt in GMO Roundup Ready soybeans in the southern US. The Stuttgart scientists found two causes of the problem: 1) glyphosate firmly latches (chelates) onto soil trace minerals, making them unavailable and 2) it eliminates or suppresses soil microbes and invertebrates. These include beneficial mycorhizal fungi) which help the plant extract soil nutrients (trace minerals included), and earthworms, springtails, isopods and man other soil organisms that recycle nutrients from plant debris into soil (trace minerals included). [As glyphosate is only one of many agrichemicals that suppress populations of soil organisms, my first question was answered; I can now see a scientific basis for lower levels of trace minerals in non-organically raised foods!

Because Roundup application rates increase sharply when GMO Roundup Ready crops are planted, this micro-nutrient problem has become more severe. Scientists at several US midwestern universities followed the lead of the Stuttgart researchers, including Don Huber at Purdue in Illinois, Barney Gordon in Kansas, and Kurt Thelan in Michigan. They have continued to investigate the trace mineral deficiencies, particularly manganese, but also zinc and others, that are an unwelcome side-effect of Roundup use (glyphosate). [The URL of a review article is http://www.environment.co.za/gm-foods-crops-biofuels-pesticides/missing-micronutrients-glyphosate.html. It was posted out of Western Illinois University by Enviroadmin on Sunday, 23 May 2010.}

It is now also known that the inserted gene in GMO Roundup Ready soybeans interferes with production of a root secretion that solubilizes minor mineral nutrients. (This is in addition to glyphosate directly chelating micro-nutrients, and suppressing or killing beneficial soil microbes and invertebrates.) Attempts to cope with the problem by fertilizing GMO Roundup Ready crops with heavy dosages of micro-nutrients have been challenged by the chelating (tight-attaching) properties of glyphosate. Similarly, human assimilation of mineral supplements in pill form is usually poor, unless the dietary supplements are bulky and food-derived! I, for one, balk at swallowing horse pills three times a day.

Nor has there been adequate analysis of the impacts on surrounding ecosystems of expanded Roundup use on Roundup Ready GMO crops. How much has it reduced the extent of field edge buffers with grass and forb (“weed”) seeds that used to be available for songbirds? Such buffer strips between and around fields are still available in a sustainably managed organic farm. More and more weeds are evolving resistance to to glyphosate; the response is accelerated efforts to develop GMO crops resistant to other herbicides, that have their own suites of risks and side-effects – which will also not be adequately tested as this is not yet required by EPA.

I can envision genetic modification for the purpose of inserting blight resistant genes from related plant species or perhaps to improve crop quality, but only after far more rigorous testing than is the current practice – directed by a third party entity (not Monsanto Corporation testing its own GMO crops!). But inserting genes for herbicide tolerance – or insecticidal proteins – seems fundamentally unwise. Expansion of organic agriculture is important for the human diet as well as for the surrounding natural environment; not just to avoid possible pesticide residues, but perhaps more importantly, for the sake of nutritional quality.

A version of this post was sent to several Connecticut members of the Environment Committee, and published by CT NOFA (Northeast Organic Farming Association)

Link: http://environmentalheadlines.com/ct/2012/03/18/a-letter-to-ct-nofa-folks-from-a-farmer/

 

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Water Woes on Drumlins

What is a drumlin anyway?  A gremlin with an aptitude for percussion?   Seriously, a rounded, elongated hill in the Connecticut landscape is probably a “drumlin”. The best known is Horsebarn Hill on the eastern side of the UConn campus at Storrs. Landing Hill in East Haddam was  in the local limelight several years ago. Lately I’ve been working on Meetinghouse Hill and Misery Hill in Franklin.  The Goshen Wildlife Management Area is another. The word “drumlin” comes from Ireland, where this land form also occurs.

The core of a drumlin hill is fine-textured, compact glacial debris, though bedrock may be underneath, poking through in a few places.   The compact “hardpan” layer (in common parlance)  may be over 100 feet thick, and dates from the prior Illinoisan glaciation (over 128,000 thousand years ago). Only the top layer, usually just a few feet deep, is sandier, looser soil, formed from the melting ice masses of the more recent Wisconsin glaciation, underlain by the compact till (scientists’ terminology).

These soils are seasonally wet.  Though the level summits seem, at first glance, to be well-suited to community development, they are challenging to develop, whether on drumlins or elsewhere, such as plastered onto the sides of traprock ridges. Most gently sloping drumlin hilltops in New England used to be productive hayfields, growing lushly in spring when soil moisture was available, going dormant in mid summer.  Pockets of wet meadow were rich in flowers, like New England Aster. Drumlin fields make fine hunting territories for raptors like barred owl.

Colorful wet meadow perched on top of drumlin.

Multiple seasonal seepage wetlands and headwaters streams flow down drumlin hillsides. They are a valuable source of clean water for the drainage basin if the drumlin is undeveloped, they but may become conduits for construction runoff.

There is more groundwater discharge on the nearly level sections of drumlin hillsides than on the steep sections. These are also prone to septic breakout.

Only a small percentage of Connecticut’s soils are compact tills but a disproportionate share of construction site fiascos and problem-plagued new subdivisions occur on hardpan soils. Wet, silty, sticky  hardpan  soils, on drumlins and also in other landscape settings,  can become a mire for heavy construction equipment because the snowmelt and spring rains “perch” on top of the hardpan. Saturated silty soils are highly erosive,  often an erosion control nightmare. Flooding problems are more severe than on absorbent soils, and water pollution from lawns and septic systems becomes a problem at lower home densities.  Break-out from home septic systems happens more often.

Typical complaints of drumlin residents: wet and moldy basements, icy sidewalks;  soggy, fungus-infested grass, burned-out grass, and dying shade trees; extended sump pump operation (not energy efficient), mosquitoes, and septic odors; and polluted down-gradient ponds.  These all become more of an issue for seasonally wet, drumlin soils, because more water stays at the surface, as it cannot soak into dense hardpan soil. (Runoff coefficients are higher, in engineering jargon.)

With careful home and septic system placement, curtain drains, and appropriate landscaping, one can avoid some of these problems – but only if home densities are relatively low.

Ironically, the loose upper soil layer of a drumlin is usually so shallow that it holds little reserve water during dry spells, so drumlin lawns need much irrigation in summer, though excess water is the problem in other seasons.   Solutions: small lawns, partially wooded yards, and/or a meadow landscape with drought-tolerant grasses like Little Blue Stem, a.k.a. Poverty Grass.

A Plea for Guidance

Could  CTDEEP and our Conservation Districts provide land use boards, planners, and developers  with more guidance on drumlins’  multiple constraints?  On-line mapping (Web Soil Survey or WSS) available from the Natural Resource Conservation Service (NRCS) does show the approximate locations of seasonally wet, hardpan soil units, like the Paxton, Woodbridge, and Wethersfield soil series.

More guidance is needed to make sure fertilizers and pesticides are not applied before or after heavy rains.  This happens all the time in Connecticut suburbs!  Turf chemicals tend to run off drumlin soils, more than off more absorbent soil types, especially when the soils are already soggy.

Few understand that watercourse setbacks often need to be wider and  septic system densities need to be lower on compact till soils, to protect down gradient wells, headwaters streams, pools, and lakes from excessive nitrogen,  in nitrogen enriched groundwater and runoff. Because they reduce lot yields, these constraints need  explanation in an official DEEP guidance document, preferably also in a  CT Health Department memorandum!

Clear-cutting may seem to be  more economical for the developer, who should be warned that this is not wise on a drumlin!  To minimize future “water woes”,   maximize  remaining tree cover when subdivisions are built. The reason is two-fold: 1) to slow the velocity of the falling rain, and 2) because trees spew thousands of gallons of water into the air as water vapor (transpiration), helping dry out those surface soils.  After clear-cutting, a drumlin hillside that used to be wet only in March and April may stay wet to the surface though June – and before long, one will see the tell-tale mottles and grayish matrix color of a jurisdictional Connecticut wetland soil.

Some, but not all engineers use underdrains and clay stops  to prevent frost heave damage to roads and utility pipes, and to allow shallow groundwater to continue to seep down slope to wetlands that depend on this water source – instead of being shunted along  roadbeds and sewer lines.  Guidance is also needed in this area.

Once aware of drumlins’ constraints and resources, town  zoning boards  will be able to  guide development more appropriately,  protecting valuable vernal pools and hillside streams, and at least a portion of the productive forests. For expansive overgrown fields on flat-topped drumlins, if the alternatives of farmland or grassland wildlife habitat are not possible, at least the damage to down-gradient headwaters resources,  from a  low density, large-lot residential community, with small lawns,  will be  much less than from a large, dense subdivision.

(First version of blog posted on 9-6-08)

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The Red Menace

Euonymus alata, also known as burning bush, is at least a clear-cut villain, unlike  some of the other invasives.    I recall spending a long June day collecting vegetation data in an an immense Euonymus thicket, a former estate  in Wilton. I did not even  observe a catbird, the most common thicket songbird in Connecticut! And beneath the dense bushes, the ONLY plants growing were Euonymus  seedlings.

This species must have high-powered chemical defenses. The glossy leaves look almost artificial (and might as well be), no holes where caterpillars or leaf beetles have nibbled.  Pickings are slim for foliage-gleaning parent songbirds.  No “chain migration”  for this species with a suite of nearly pre-adapted species waiting in the new world, to make use of the new immigrant – and keep it in check, as has happened with the cherries.  Gray’s Manual of Botany (Fernald) shows only two  native  cousins  in this genus, and neither has a range that overlaps southern New England or Long Island.

Euonymus alata, from Asia,  is an effective invader of forests, because it grows well in shade, unlike bittersweet, multiflora rose, everlasting pea, and Phragmites. It spreads well by runners as well as seed. Unfortunately, it thrives especially in the mineral-rich, sub-acidic  soil of traprock (basalt)  ridges.

Euonymus has overrun much of Peck Mountain, in north Cheshire,   because suburban yards on the flanks of the traprock ridge provide abundant seed sources.  As recently as the mid 1980’s the ridge crest and its steep talus slopes were botanically  diverse and special. At that time they were clear-cut  CTDEEP Critical Habitats, per the CTECO website (sub-acidic forest,sub-acidic talus slope, and sub-acidic summit  catgories.) Since then, these habitats  have become near monocultures of burning bush. The Euonymus even thrives in shallow soil pockets on ledges!  Some rare Staphylea trifolia  (bladdernut)  and marginal wood fern remains on the steep west slope  of Peck Mountain, and I last year I noticed a single non-blooming columbine patch.  The oak fern, dwarf saxifrage, and anemonella appear to be gone.

After that Wilton experience and a recent  eye-opening hike on Peck Mountain,   I knew we had to get rid of the burning bushes in our own yard. Emotionally, it was not so easy.  This is a beautiful shrub, especially when crimson in the fall, and it makes a dense, tidy hedge.  The wings or flanges on the stems also look interesting in winter.  Our bushes had special meaning because they been given to us by relatives who were dear to us.

Control  was very quick and simple, from a practical standpoint. We snipped them with a lopper, and painted the freshly cut stems  with Brush-B-Gon (8% triclopyr). For those who simply cannot kill their prize burning bush, thoroughly shearing off the seeds each September, with hedge clippers,  will at least prevent further spread by birds.

Connecticut nurseries are still battling the environmental regulators, to prevent an outright ban of Euonymus alata, because this is such a popular, lucrative species for  the landscaping business, especially for commercial sites.

For illustrations and discussion of other invasive plants, see the accompanying facebook album “Invasives- A Devil’s Advocate Perspective” (Sigrun Gadwa)

http://www.facebook.com/media/set/?set=a.496792513908.273505.588968908&l=ac65ae4d58

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