All posts by sigrungadwa

Consulting Ecologist and Registered Soil Scientist. My firm, Carya Ecological Services, LLC conducts inventories of vegetation, wetlands, and habitat; wetland delineations; and ecological assessments - for open space grants, application reviews, and applications for open space/cluster developments. We work either as the lead firm or as a subconsultant. I have a Masters Degree from UCONN-Storrs, Dept of Ecology & Evolutionary Biology (1997) & a Bachelors from Brown U. in Biology.
Botany, food chain, Invasive Species, Wildlife Habitat

Pink Ribbon or Blue?

Why we should proactively control Ailanthus altissima.

Ailanthus bud scar
Ailanthus bud scar is very large with numerous bundle scars – quite unusual.

Early spring, before thicket vegetation in in full leaf, is a good time to locate sprouts and trees of “Tree of Heaven” (Ailanthus altissima) – if we know what they look like.   Today, at a restoration site, I was tying blue ribbons on staghorn sumac (Rhus typhina), with exceptional wildlife habitat value. Pink ribbons were tied on young, invasive Ailanthus, which is remarkably like sumac, though unrelated. Ailanthus is not yet an abundant invasive in Connecticut, but it is a serious threat. Basal treatments of Ailanthus with triclopyr ester in oil are planned for mid-July. Blue stands for “save”, pink stands for “treat”. We do not want to treat the staghorn sumac accidentally!

Staghorn sumac has a narrow bud scar encircling the bud
Staghorn sumac can be distinguished by its narrow bud scar encircling the bud.

To tell them apart before leaf-out, use an obvious Ailanthus field mark: the huge leaf scars with numerous bundle scars. Staghorn sumac has a narrow U-shaped bud scar that wraps around a furry bud. Viewed from a distance, both have similar thick branches, but Ailanthus bark is smooth, whereas staghorn sumac has “velvet” on the thick, blunt, antler-like twigs, obvious in all seasons.

In summer young Ailanthus looks like a sumac on steroids, and when mature it resembles black walnut.  It grows 80 to 100 feet tall, and its compound leaves have up to 40 leaflets.

Ailanthus foliage
Ailanthus foliage

Each Ailanthus leaflet has smooth edges except for one or two snaggle teeth at the base, whereas sumac and walnut leaflets are serrated from tip to base. For more information on lookalikes, see:

                                            https://extension.psu.edu/tree-of-heaven     and

https://mortonarb.org/plant-and-protect/trees-and-plants/staghorn-sumac/.

Cluster of spotted lanternfly nymphs
Cluster of spotted lanternfly nymphs

Why is proactive control of Ailanthus a priority? Foremost, Ailanthus fosters spotted lanternfly (Lycorma delicatula), a serious, polyphagous pest of vineyards, orchards, street trees, and many other woody plants.  Both come from  China. The lanternfly reaches high population densities, killing woody vines and saplings and damaging full-size trees. This opens up the landscape for colonization by Ailanthus, which requires high light levels to grow. Lanternfly nymphs can feed on a wide range of plants, but a 2020 study showed that nymphs that develop on Ailanthus grow more quickly and produce more offspring than those on other trees species, like maple and walnut.  Fall lanternfly nymphs on Ailanthus were much more likely to lay their eggs before frost.

 

Ailanthus leaf tissue is also the source of the cytotoxins (quassinoids) that confer a repugnant taste that protects spotted lantern flies from birds and other predators. Birds that have experienced the foul-tasting nymphs will also avoid palatable nymphs that have fed on other plants. (It is unclear to what extent the quassinoids are also toxic.) Through social learning, this avoidance behavior hinders expansion of avian biological control, as explained in a 2024 article by Daniel Stroembon et al.

 

Ailanthus emits volatile attractants that attract spotted lanternflies like a magnet, sometimes by the thousands.  Where lanternfly is well-established, in the mid-Atlantic states, Ailanthus trees are used by pest control firms to trap these pests, before killing them en masse. Spotted lanternfly is just beginning to reach Connecticut.  Scattered early colonizers are likely to bypass an Ailanthus-free community. More aggressive control of Ailanthus altissima will slow down the spotted lanternfly invasion.

 

Without a doubt Ailanthus altissima meets Les Mehrhoff’s widely accepted definition of an invasive species:  It has very high reproductive potential and is able to expand into natural areas and outcompete native plant species.

  • It is a fast-growing, clonal tree, and an expanding patch can take over more than half-acre of habitat, outcompeting native tree and shrubs, in part by means of allelopathy. Ailanthus roots secrete chemicals that inhibit growth of other competing plants, some species more than others.
  • It produces vast numbers of seeds. According to a 2007 dispersal study published in Plant Ecology, Ailanthus altissima “is able to disperse long distances [by wind] into fields and into mature forests and can reach canopy gaps and other suitable habitats at least 100 m from the forest edge. It is an effective disperser and can spread rapidly in fragmented landscapes where edges and other high light environments occur.”
  • Water-borne seed dispersal is also important. Even in a truly urban setting, where wind-dispersed seeds would not reach farmland or natural forests, Ailanthus seeds wash into catch basins, and then into rivers, and floodwaters deposit the seeds on river levees. Throughout the US, its distribution follows river networks.
  • This tree also excels at seedling establishment. Betty Smith got the science right in A Tree Grows in Brooklyn. Ailanthus can colonize cracks in pavements – or crevices in cliffs. I was dismayed to find an Ailanthus clone on the steep mountainside just west of Castle Craig, in Meriden. I also saw many on rip-rap Amtrak railroad embankments in Old Saybrook. It needs ample light, but not deep, fertile soil.

Ailanthus altissima is relatively easy to control but often overlooked, except for the mature female trees, which bear conspicuous masses of dark red flowers in late summer and early fall. Females are sold, bare-root, on-line.  If money or volunteer resources are short, the priority should be removal of the female seed-producing trees. Trycera, Pathfinder and Garlon 4 are safe, systemic herbicides that can be purchased on-line and applied to the lower stem of Ailanthus suckers.  They are all triclopyr esters, with an oil carrier, but only Trycera may be applied by volunteers and property owners without a pesticide applicator’s license in Connecticut, though not for pay.  Mid-summer is the optimal time to apply, to minimize resprouting.

Per a 2023 article in Forestry and Wildlife by Nancy Loewenstein et al, basal oil application of trichlopyr ester is most useful “where the target tree or shrub density is moderate to low, manual labor is available, and dead standing trees and shrubs can be tolerated.”  The method should be used only in low to moderate density invasive stands, to prevent changes to the soil microbe community, and impacts to non-target plants via root systems. Note that treatment of trees over five inches in diameter requires a modified “hack and squirt” method. (See Aces link to the Forestry and Wildlife article below for more information).

This invasive tree is an indirect economic threat as well as an ecological one. EDRR (Early Detection and Rapid Response) should be a high priority for Tree of Heaven. It would be helpful if land trust stewardship directors and town tree wardens could be alerted about Tree of Heaven (Ailanthus altissima) occurrences, so infestations can be nipped in the bud and further spread minimized.   Spotted lanternfly sightings should be reported to  CAES (The Connecticut Agricultural Station) using this link:  Spotted Lanternfly – SLF (ct.gov).

Should male Ailanthus trees (which produce no seeds) be spared in urban areas or school yards?  The answer is no, despite the fact that a mature Tree of Heaven blesses its neighborhood with shade, cooling, beauty, and air pollution filtration, like any large urban tree. Their scent, unpleasant to humans, is a magnet for stray lantern flies, and will attract stray dispersing spotted lanternflies. Other urban trees will soon be infested as well. These male trees will bear no seeds, but they can be productive lanternfly nurseries, yielding thousands of vile-tasting nymphs. As discussed in the 2024 Stroembon article, local birds will learn to avoid spotted lanternflies altogether, and such aversion does spread through social learning. This will reduce the potential for effective avian biological control of palatable – and nutritious – lanternfly populations in orchards, preserves, and treed residential neighborhoods.

Landenberger, Rick E. Nathan L. Kota , and James B. McGraw. 2007. Seed dispersal of the non-native invasive tree Ailanthus altissima into contrasting environments.  Plant Ecology (192):5–70.

Loewenstein, Nancy Stephen Enloe, Ken Kelley, and Beau Brodbe.  July 21, 2023. Basal Bark Herbicide Treatment for Invasive Plants in Pastures, Natural Areas & Forests. https://www.aces.edu/blog/topics/forestry-wildlife/basal-bark-herbicide-treatment-for-invasive-plants-in-pastures-natural-areas-forests.

Stroembon, Daniel, A. Crocker, A. Gray, A. Sands, G. Tulevich, K Ward, Swati Pandey.  February 2024. Modelling the emergence of social-bird biological controls to mitigate invasions of the spotted lanternfly and similar invasive pests. Royal Society Open Science. 11(2) https://royalsocietypublishing.org/doi/10.1098/rsos.231671

Uyi, Osariyekemwen, J. Keller, A. Johnson, B. Walsch, D. Long, and K. Hoover. 2021. Spotted Lanternfly can complete development and reproduce without access to the preferred host, Ailanthus altissima. Environmental Entomology nvaa 083.

http://doi-org/10.1093/ee/nvaa083.

By Sigrun Gadwa, Carya Ecological Services, LLC    www.caryaecological.com     3-16-24

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Coastal Forest – a CT DEEP Critical Habitat

FULL SET: https://www.facebook.com/media/set?vanity=sigrun.gadwa.56&set=a.610140136753118

Photos show a low-lying coastal forest in Old Lyme, Connecticut, on a forested ~fifteen-acre “peninsula” bordered by brackish marsh. It is just east of the Connecticut River and north of the Amtrak RR line. Upland forest is mostly limited to roadsides and embankments, but has the full suite of species typical of this forest community, as described below in a Sea Grant (UConn) Fact Sheet. So little Coastal Forest remains in this state , due to coastal development and farming, that it has been designated a Critical Habitat by CTDEEP.

https://climate.uconn.edu/coastal-resources/forests/

COASTAL FORESTS

Coastal forests are found along the coast and are subject to a maritime climate. These forests do not receive daily salt spray (as a true maritime forest may), but can be subject to wind and salt spray during storm events.

VEGETATION

Oak trees, particularly black, white, chestnut and scarlet, are the dominant trees of these forests. Other trees that may be intermixed with the oaks include black cherry, sassafras, red maple, beech, tupelo, white pine and pitch pine. Low lying shrubs such as low bush blueberries and black huckleberry. Vines are very characteristic of coastal forest edges and openings including Virginia creeper, poison ivy, grape and greenbriers. (I would add hackberry and American Holly, as characteristic trees, and bayberry, a salt tolerant native shrub.)

WHY THEY ARE IMPORTANT

Due to intense agricultural and development pressures, Connecticut has very little forest left within the coastal zone. What is left is often heavily browsed by deer and invaded by non-native species. Raising awareness of where and what these forests are will aid in protection and restoration efforts.

 

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Tri-Town Preserve in Gabbro Country

Avalonia Land Conservancy is the proud steward of the 527-acre TriTown Forest Preserve in southeastern Connecticut.  Well buffered by extensive additional protected open space, including Natchaug State Forest,  this preserve not only has a wide range of pristine wetland classes. It also has rugged hills with cliffs, ledges, talus slopes, plateaus, shallow-to bedrock soils, and rocky summits.     Forest cover includes well-drained deciduous forest, moist to wet bottomland forest, and mixed hardwood evergreen forest, and ridgetop oak blueberry woodlands.  These habitats are accessible to the general public via a well-marked trail system.  Four annotated photo-albums provide virtual guided nature  hikes.   The Preserve website has an excellent trail map and other useful information. https://avalonia.org/tritown-forest/

Links to four annotated photo albums  document four early fall field trips, gathering data for a botany report to Avalonia Land Conservancy. They show the plant communities  in this large interesting Preserve in Southeastern Connecticut, with gabbro bedrock.

Gabbro Country – Album 1: September Walk in Tritown Preserve

Gabbro Country – Album 2: Low Hills West of Swain Mountain

Gabbro Country– Album 3: Towards Lambert Ridge from the South

Gabbro Country – Album 4: Rixtown Mountain

The albums were generated using Facebook, but are now accessible to anyone via this CaryaEcological.com website.

The underlying bedrock  of the TriTown Forest Preserve is Connecticut’s only major formation of Preston gabbro. formation). This an ancient igneous, mafic bedrock, with minerology closely akin to basalt, weathering into mineral-rich soils. Habitat at the base of gabbro cliffs is fed by mineral-rich seepage, and able to support “rich -site” plants.

Due to their much greater age, the gabbro hills in the TriTown Forest Preserve and its surroundings are more severely weathered than the basalt and diabase ridges in the Metacomet Ridge. The low, flat-topped hills, blanketed with acidic glacial till,  have typical soil for the state’s eastern Highlands:  acidic and infertile, though rich in humus.  However, the higher hills still have areas with sub-acidic, base-rich soils, and groundwater seepage through gabbro soil parent materials is still calcium-rich, resulting in slope-base soils that are mineral-rich and circum-neutral. Gabbro ridges support localized  minerotrophic plant communities, comparable to those on traprock habitats in central Connecticut.   Although they may support unusual and uncommon plant species, gabbro habitats also support healthy populations of regionally common species, and the insect and wildlife populations that depend on them.

The summit/upper slope plant communities were a focus of a 2019 botanical study led by Carya Ecological Services and the CT Botanical Society. Certain dominant and characteristic plants were present on well-drained gabbro hilltops throughout the site, regardless of elevation. This includes Lambert Peak and the crest of Rixtown Mountain, both over 500 feet in elevation.  Well-drained upper slopes and plateaus, and foothills had a maximum height of 300 to 400 feet. These anchor species include pignut hickory, white oak, black oak, red cedar, sugar maple, Penn sedge, and heaths (black huckleberry and low blueberry).   The most diverse plant species assemblages were at the highest elevations and in cliff-base talus, which also supported massive sugar maples .

Shallow bedrock increases the frequency of tree blowdowns, regularly creating new openings, and helps to maintain high species diversity in summit habitats.  (Pickett & White, 1985)   Rocky summits usually have tawny patches with little blue stem grass.  Upper slopes usually have an open understory, with a “lawn” of Penn sedge, scattered maple leaf viburnum, and scattered large boulders.   Especially at the high elevations, many other wildflower and native grass and sedge species are interspersed.On level plateaus along the ridges, stunted trees and saplings are typically widely spaced within a broad, low patch of twiggy heaths, as shown in the  photo below.

Concentrations of interesting herbs often occur beneath red cedars, an observation warranting further study.  These included hairy bedstraw, ebony spleenwort, smooth whitlow grass, red columbine, dwarf saxifrage, wild oat grass (Danthonia spicata), panicled hawkweed, wavy-leaved aster, rue anemone, blue goldenrod, gray goldenrod, and silverrod.

Symphiotrichum undulatum (wavy-leaved aster)

Other species occurred only in one or two sizable patches, e.g. lopseed, hoary mountain mint, Bosc’s rosette panic grass, and bear oak. Uncommon low shrub and herb species with very limited occurrence in the TriTown Forest Preserve include Carolina rose, dwarf chinquapin oak, skunk meadow rue, rock muhle (Muhlenbergia sobolifera), Lyre-leaved rock cress and stiff rock cress.  The two cresses are important host plants for a rare butterfly species, the orange-tip falcate butterfly.  Blunt-leaved woodsia was found in only one cliff-top location.  Summits also support scattered dwarf Carolina roses and occasional small individuals of an unknown hawthorn species, too young to be identified – a puzzle for future investigation.

Moss and lichen flora are also important in sunny or partly shaded summit habitats.  Drought-tolerant mosses such as juniper haircap moss (Polytrichum juniperus) are early colonizers of bare, shallow soil, and help to build up organic matter levels. Hedwigia cilata, medusa moss, is a partially shade-tolerant moss found on a large boulder face.  Schistidium apocarpon (rock beard moss) is another boulder moss that tolerates dry conditions.  Crustose lichens are on exposed rock surfaces – boulders, cliff faces, and bedrock outcrops.  These include rock shields, in the Flavoparmelia and Xanthoparmela genera, and smaller species such as the smokey blue-eyed lichen, Porpidia albcaerulescens.  Lichen rhizoids which penetrate rock crevices, and secretions such as oxalic acid help to weather bedrock and release the minerals needed by plants.

Also encountered in open, sunlit gabbro summits are occasional plants, such as smartweeds, hawkweeds, fleabanes, common mullein, or hawk weeds, that are typically found, as well, on trailsides and other open disturbed areas.  Wavy-leaved aster is an example of a native aster found in two habitats: trailsides and gabbro summits.  Others  are  exotic species, but still useful for pollinators, and as seed producers for wildlife. They are poor competitors, but fecund, and able to colonize open, disturbed sites.

In this gabbro ridge system, invasive plant colonizers were absent or extremely sparse in 2019, after a very thorough invasive plant eradication program during the prior year. Mugwort would thrive on gabbro summits and rock outcrops but has not reached this preserve. With the steadily increasing usage of the preserve by hikers, annual early summer checks for mugwort seedlings are recommended, so they can be pulled before establishment of rhizomes that would sprout again, after pulling.

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Botany, food chain, Invasive Species

ALERT: MOW DOWN MUGWORT BEFORE SEEDS RIPEN

ALERT: MOW DOWN MUGWORT BEFORE FROST,

WHEN ITS SEEDS START TO FLY

Connecticut plant scientists and volunteers who work on invasive issues are gravely concerned that mugwort (Artemisia vulgaris) is spreading rapidly throughout our road network. Minute seeds are blown across the winter landscape and carried in road dirt, in tire treads, on undercarriages, and by snow plows.  The seeds germinate well in bare spots,  and new mugwort patches spread from roadsides into adjacent meadow and forested habitats. A two- meter-tall plant yields up to 200,000 seeds!

We urge a time-sensitive measure: please mow the mugwort on your own land and encourage roadside mugwort mowing on municipal, DOT, utility,  & commercial land preferably before a hard frost, when the tiny seeds start to fly. Weed-whack mugwort plumes behind guard rails.   If the mugwort is past bloom but still not brown and crisp from frost,  the cuttings can be moved and piled up, then covered with  mugwort-free hay mulch or brush,  or bagged for disposal, without risk of dispersing the seeds during the initial moving process. However,  a new patch is likely to form at  the disposal pile.   In a large existing patch, it is best to leave the cuttings in place.

Mugwort was repeatedly transported from Europe to New England several centuries ago  in ship ballast. Ignored for centuries. as a tough, clonal weed of vacant land, it has begun to spread by seed, as well as by rhizome bits – found even in screened commercial topsoil. Each established patch has a large network of vigorous rhizomes (underground stems), like Japanese knotweed, also shown in bloom in the background of photo at left, which depicts a stand of mugwort in bloom, relatively low because it was mowed in early summer. Note that  most  Japanese knotwood clones have non-viable seeds, but seed germination has been detected in a few studies, an urgent research need, as Japanese Knotweed is, like mugwort, a “supercompetitor”.

Mugwort grows in sun or shade, and in droughty or soggy soil. Dense mugwort colonies crowd out even the hardiest native goldenrods, grasses, and asters, but mugwort has far less ecological value. The seeds are too small for birds to eat. In September, mugwort plants form plumes with tiny, dull white flowers  which yield no nectar, though the abundant wind- dispersed pollen causes hay fever. The finely dissected, gray-green leaves have a strong medicinal smell, and are eaten by few herbivores;  because it repels fleas and vermin, mugwort has been  used as bedding for  livestock. Mugwort often reaches over 4.5  feet in height, though early summer mowing, shade,  or very infertile soil may reduce its mature height to 1-2  feet.  Artemisia vulgaris threatens Connecticut’s biodiversity, agriculture, public health, and natural scenery.  Simple mowing can much slow down its advance. Other control measures include double layers of landscape fabric or other mulch.  Treatment with herbicides is very challenging, due to the deep, dense rhizomes.

Unfortunately, mugwort has begun to colonize some of Connecticut’s most special, beautiful places where uncommon and rare plants can still be found, such as rocky summits, sand plains, and river floodplains, termed “Critical Habitats” by the Wildlife Division of the Connecticut Department of Environmental Protection (CTDEEP).  On a CBS botany field trip in North Haven, last summer, we noticed that mugwort is now abundant in the beautiful pin oak forest east of the Quinnipiac Marsh and in a silver maple floodplain forest along the Still River, in a Weantinoge Land Trust preserve in New Milford.

In a botanically diverse state park or preserve, careful pulling of young plants may prevent establishment of new colonies, but only if done before  formation of rhizomes (underground stems). Research is needed to find out at what stage  this takes place, and also how long rhizome fragments remain viable. Snow plows & street sweepers likely disperse seed & rhizome bits. Would additional mowing during the summer be helpful?

This photo of a mugwort seeedling  (or rhizome sprout) was taken in about 2015 at the edge of a gravel tracking pad in Meriden, at the Platt High School  construction site (where I was an erosion & sediment control monitor). Nearby, I noticed that along the Sodom Brook  linear trail the city practice of  trailside mowing in early summer was allowing mugwort to coexist with native goldenrods and small white asters, over a two-year period – but for how long?   Frequent mowing will help control a mugwort colony, but will result in a mugwort-dominated lawn, NOT a scenic meadow, with perennial grasses & flowers like chickory, goldenrods, Joe Pye, ox-eye daisies, asters, and Vernonia.

Members of the Right-of-Way Sub-committee of the CBS Ecology & Conservation Committee are concerned that Eversource’s new wide gravel roads and gravel pads along powerlines, will in all likelihood become new mega-seed sources, and spread into remaining ROW habitats, which are especially rich in biodiversity, including rare Lespedeza bush clovers, shrubland birds, Eastern box turtles, and the New England cottontail, our only rare rabbit species.

Although mugwort seeds are known to remain viable for several years, protracted sprouting from the seed bank may not be an issue, after a nearby seed source is controlled, according to Kathleen Nelson.  She is the tireless CIPWG volunteer scientist, who has been leading successful efforts to slow down the advance of  Mile-a-Minute vine in Connecticut. She made a welcome discovery: mugwort seedlings entirely  stopped sprouting on her land,  the first year after a large, neighboring mugwort stand was mowed  in early October of 2015 & 2016.

The Connecticut Botanical Society suggests you call an official you know at your town hall, and explain why it is wise to control mugwort colonies; mention that prompt stabilization of  bare soil will help eliminate seed beds for mugwort patches, as well as protect water quality.  You could e-mail the link to this on-line article. The photo below shows mugwort and Japanese knotweed colonies on a  former soil pile.  Eversource officials and/or the CT Siting Council also need to understand that even thick gravel pads are readily colonized by mugwort, and become a significant seed source, statewide.  

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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 die-back 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. 

2) It is also important to take down stricken trees, and properly treat the infested bark and branches.  Beginning 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 bio-control 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 can be 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, PWS  for CBS.  Contact: sigrun.n.gadwa@gmail.com

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

Botany

Where are the Starry Campions?

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.

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. 

The 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. 


by  Sigrun N. Gadwa, MS, PWS

 

 

Botany, Invasive Species, Native Landscaping, Uncategorized, Water Quality

Lesser Celandine – a Temptress

Lesser Celandine

When 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 Island

 

Uncategorized

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 WinterOne 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. 

 

 

 

Botany, Invasive Species, Soils, Uncategorized, Water Quality, Wildlife Habitat

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.

 

Botany, Invasive Species, Soils, Wildlife Habitat

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.