|
The
Physical Removal of a Recent Population
of Phytolacca http://www.mobot.org/plantscience/ResBot/niag/ |
|
The
Physical Removal of a Recent
Population of Phytolacca by Patricia M.
Eckel
The Physical Removal of a Recent Population of Phytolacca P. M. Eckel January 22, 2012 VIDEOS: Introduction The The nationally and internationally recognized biological
resources of the Niagara River environment have been severely compromised
throughout the years since the establishment of the Niagara Reservation,
leaving challenges for the stewardship and custodianship of these areas on
both sides of the River. One of the most serious challenges is the control of
noxious species and the absence of functional policy commitment and resource
allocation for this control by the governments involved in the It was while hiking along the gorge of the The species was Phytolacca
In the General Methods Site work took place on Saturday, November 26, beginning at 12:00 PM ending at 4:00 PM, or approximately four hours.. Activity took place in light, brightly overcast, unseasonably warm, but still cool conditions, suggesting an extended season of growth for the year 2011. Tools used included secateurs, a heavy metal shovel, a heavy pitch-fork, a trowel to pull away loose soil from the roots, several large, durable plastic bags, smaller durable bags to collect and retain any fruit or seed material, a camera to record activity and results. Gloves were used at all times to prevent toxic plant juices from skin contact. Care was taken when drinking from water bottles to prevent inadvertent ingestion of toxic emetic, purgative plant juices.
Care must be taken with any chopping tool (such as a shovel) that the roots are not fragmented. Some web sites suggest that only the top crowns of the root need be removed, but others have reported new shoots arising from root fragments left behind in the soil. Every attempt was made to remove the entire below-ground structure. Due to the significance and cultural importance of the biota of the site, invasive plant removal must be careful, as though one were removing material from an archeological site. Bags and tools were kept close to the stems being extricated to avoid migration of plant parts. For several days the area had been subjected to rather heavy seasonal rains. The Thursday and Friday (24th and 25th November) were clear. There was no precipitation on Saturday the 26th, nor the 27th. The soil at the site was thus saturated and rather loose, hence relatively easy to manipulate and to prevent root pieces from remaining and possibly regrowing. In November, much of the fruit of Phytolacca The stems of the plants are succulent, with chambered pith, and deciduous down to the ground. Many had been bleached of pigment (from their ordinary bright purple color) and were at first inconspicuous, and difficult to see as an apical portion of large underground roots. Several plants had only the main stem remaining, the branching upper parts with their fruit already rotted away. It is likely that after a few more weeks, the stems would have rotted quite down to the green buds at the apex of the thick underground root and the population would have been otherwise undetectable during the winter months.
Although a wet November is recommended as a good time to remove the large, carrot-like roots, the colorful deep purple fruit-clusters should have been removed earlier in the season at a time to be determined: in Chautauqua County in the southern tier of western New York, anthesis is stated as July 7 with fruit on August 2 (Eaton and Schrot 1987). The August date for collecting the seed for removal is reinforced by Farmer and Hall (1970), see also Steinbauer and Grigsby (1956). The area is along a weedy approach from the top of the
trail from the parking area below the Robert Moses Overpass just south of the
The gorge and portions of the The top of new trail down to base of gorge: the trail is covered by gravel over a manufactured kind of cloth that reduces erosion on the path, which is relatively steep. The path appears to have been prepared by a small bulldozer. The upper portion of the path leads down rather gradually along the top of the talus slope, along the base and face of the dolomite caprock, terminating before a man-made opening in the caprock that is faced with a metal door and lock. From the emanation of sewage odors it is presumed that this door is associated with a CSO (Combined Sewer Outlet) associated with drainage in the urban areas adjacent to the bridge and parkway. A small area of seepage from the caprock was evident on the first leg of the descent that crossed the path, but which is probably not evident except after precipitation. All path areas occur on natural talus rubble and soils except in the first leg from the gorge rim. A heap of transported soil is associated with the CSO which constitutes transported soil mixed with rubble (rubbish constituted of old bricks, old broken glass) and large angular talus cobbles mostly less than 12” on the longest side, coupled with black cinder covering all and exposed at the surface. It is assumed that this rubble was deposited some years ago to form a path down to the CSO, which displays signs of trampling in the weeds in front of the door indicating the door is in relatively frequent and recent use. The CSO door is located at the top of the talus slope and is associated with the dolomite caprock. A heap or deposit of transported soil at the CSO door together with the rubble indicates that the soil was accumulated in a weedy waste area and deposited at the site to form a path down to the CSO. The approach on the first leg of the trail leading down to
the CSO is dense with a weedy flora of non native species. Species noticed in
November included: Alliaria officinalis
(Garlic Mustard), Arctium minor (Burdock), Chrysanthemum parthenium (Feverfew), Dactylis glomerata (Orchard Grass), Daucus carota (Queen-Anne’s Lace), Hesperis matronalis (Dame’s
Rocket), Nepeta cataria (Catnip), ), Poa interior (Interior Meadow-grass), Panicum capillare (Witch-grass), Rubus idaeus (European Red
Raspberry), Solanum dulcamara
(Bitter Nightshade), basal rosettes of Verbascum
thapsus. Aster pilosus (Old Field Aster) may be considered to be native
to the area. Since 1934, when it was not reported by Zenkert for the area in
a fifty mile radius around a point in the City of A large shrub of Ligustrum
sp. (Privet) at least five years or more old grew at the cliff base, with no
descendents observed. Also Rhamnus
cathartica (Buckthorn). The only species of plant considered rare in From the CSO door the path makes a sharp right and plunges steeply downward to the buolder-field along the path at the base of the gorge. A steel cable is affixed to boulders to assist the hiker up and down the talus slope. The Pokeweed area is directly in front of the CSO door. No plants of Pokeweed were found either on the approaches to or descent from the gorge rim. Examination of the rim or crest of the gorge directly above the Pokeweed-CSO site and beneath the overpass of the Robert Moses Expressway revealed a wooded vegetation remarkably clean of alien weeds (and garbage), comprised mostly of grasses and Solidago altissima, Solidago flexicaulis, with an Arctium minus plant and a liliaceous weed that may have been planted. Old patches of Vinca minor (Periwinkle) were present. Some Phragmites occurred due to a slight seepage amid the grasses. The largest individual of the Pokeweed population was surrounded by ‘haloes’ of younger, smaller plants extending out from the central plant in front of the CSO door. Seven large Pokeweed plants were removed at the end of the path leading from the crest to the CSO door.
All native soils on the lower talus slopes seem relatively clean in comparison with the weedy path approach, and filled with native plant species, in November, mostly Solidago and Aster species, as on the gorge crest above, particularly, Solidago flexicaulis and S. altissima, Rhus toxicodendron (Poison Ivy), and some Polymnia canadensis (Small-flowered Leafcup), all typical of the talus slopes in this area, except for occasional stems of Verbena urticifolia (White Vervain), which was rather unexpected. The only other species with bright berries present at the site were the red berries of Solanum dulcamara (Bitter Nightshade). Before Pokeweed removal, the large plants formed a screen in front of the CSO door, concealing it, which may have been part of an intention to establish it there. Results A total of 57 roots and four seedling roots were removed during a period from 12:06 PM to 4:00 PM, or around four hours. The area involved was approximately 20’X 5’ cleared, or 100 square feet. If in three hours, a 100 sq.ft.’ area was cleared, then 33 sq. ft. per hour = 1/2 square foot per minute. All above-ground parts and their associated below-ground parts were removed from the population of Pokeweed located in front of the CSO door. Care was taken to remove the root tips in the below-grown root system. All fruits remaining on the stems were removed. All plant materials were bagged and removed from the site and disposed of in city trash containers. At the end of the day, there was no evidence that this population had existed at the site and all signs of disturbance had been removed. No other species of plant was disturbed other than a few plants of the abundant Leonurus cardiaca (Motherwort) with which the Pokeweed was growing. Examination of areas peripheral to the population, above it on the gorge crest and below it at the base of the gorge were examined for additional populations of Pokeweed, and none could be identified. The eradicated population seemed relatively new and quite mature, probably producing fruit for at least one season (and probably several) before the 2011 season. Several rather large stems that occurred with their fruiting tops gone were removed. Seven additional medium-sized plants were removed on both sides of the path just up from the main population (total of ca. 14 stems). Discussion Due to the historical and cultural values associated with the biota of the site, the attitude to adopt when manipulating the biota of the site is curatorial (something akin to cleaning and clearing an archaeological site) to preserve the valuable elements of the plant community and the natural environment. It was also important to restore the site to a clean condition as it was and is being used by the public. The Niagara gorge alone is a 14 - mile combined biological
environment, with seven miles in Every invasive or otherwise noxious or inappropriate
species, such as horticultural or patented species used in inappropriate landscaping
activities, has its own properties. Some are easy to remove, some difficult,
some relatively rapidly recolonize through seed set, underground rhizome
development, cloning, etc. The removal of some species results in an
extirpation of that species from the In the case of the Pokeweed plants, even though the single population had probably existed for several seasons, there seemed to be no observable evidence in November, 2011, that the species had expanded beyond the immediate and expanding periphery of the Mother plant, that is, birds, animals or simply gravity downslope had not contributed to dissemination of this species from the site. The major investment of energy with Phytolacca
That the climatic conditions were so mild for November at Niagara suggests a contribution to an extended season of growth of all green plants and a modification of cold temperatures as a limit on dispersal, competition and vigor between species and their populations, either weedy, alien and native alike. The Pokeweed site was determined to be a Mother Site by the author, that is, the surrounding landscape was free of this particular species, the undisturbed landscape free of not only this species, but many others as well, as seen in the densely populated biologically ‘dirty’ soils used to prepare the path from the gorge rim to the CSO door. Many other such sites may be seen in the environments along the Niagara River and its gorge in the public lands areas, such as one tree of Cotinus coggygria, Smoke-tree, a horticultural species, ringed by its descendents at Artpark, Rhamnus cathartica (Buckthorn) planted with Lilacs, Ligustrums and other horticultural aliens, Salix matsudana (Cork-screw Willow) planted on the spoil area overlooking Artpark and on the crest of the gorge by the Lewiston-Queenston Bridge, by the various lawn weeds creeping into DeVeaux State Parks through the backyards of residents neighboring the northern bountary of the park, especially Lapsana communis (Nipplewort) the vector of which can be seen from Lewiston Road stretching west through DeVeaux Park across Whirlpool State Park and down into the base of the gorge of the River.
The absence of Phytolacca
The station before the CSO door may be examined for regrowth in the spring of 2012 (the year subsequent to the year of removal), but it is unlikely that additional plants will be found in the first spring, due to the complex and large nature of the rootstalk. The smallest stems observed occurred directly within the entrance-recess to the CSO door, and these had relatively large roots. It is likely that the plant is a biennial, with a shoot developing in the first year, and the stalk in the second, due to the development of a large, fleshy root. The search for seedlings in the spring may be undertaken, but it is likely that two years may be necessary to readily identify the plant, or else it would need a full summer’s growth to readily identify new seedlings - such as reexamination in November 2012. From images posted on the internet, seedlings show red stems, although, like the older plants, the leaves are green. It is assumed that birds are the primary vector for longer distance dispersal than within a few feet of the mother plant. It is perhaps theoretically doubtful that this population would have contributed in any significant way to dispersal in the immediate area, a suggestion that might be easy to confirm or disprove in 2012 during the growing season. For restraint on the expansion of populations of this species, it is recommended that all flowers and fruit be removed from the stems in August, taking especial care that the plant is not stimulated to produce new flower and fruit structures - presumably to remove these structures as late in the season as possible before fruit fall. Care must be provided that fruits are removed before an interest by birds is developed. Racemes on the plants removed did not seem foraged by birds, perhaps because there were so many other food options, and the population was small. Roots are best removed after the soil is well moistened by heavy rain in fall (November) and spring (March or April). It is easier to remove these plants where the root plays a significant factor in the durability of the population when the soil is loose and saturated.
Conclusions For removal of a species such as Phytolacca A total of 57 roots and four seedling roots were removed in all during a period from 12:06 PM to 4:00 PM, or around four hours. The area involved was approximately 20’X 5’ cleared. If over four hours, a 100 sq.ft.’ area was cleared = then 25 square feet per hour = 1/2 [0.42] square foot per minute. If $7.25 is the minimum wage per hour, then the minimum cost to employ a laborer or contract worker to remove this population of Pokeweed would be $25.00. Acknowledgements. The author would like to thank Meg Janis for arranging
permission to study the removal of Phytolacca
Literature Cited Eaton, Stephen W. and Edith Feuerstein Schrot. 1987. A
Flora of the Vascular Plants of Farmer, Jr., R. E. and Geraldine C. Hall. 1970. Pokeweed seed germination: effect of environment, stratification, and chemical growth regulators. Ecology. Vol. 51(5) pp. 894-898. Steinbauer, G. P. and B. Grigsby. 1956. Interaction of
thermoperiod, light and substrate in the germination of seeds of pokeweed
(Phytolacca Voss,
Edward G. Zenkert,
Charles A. 1934. Flora of the
|
|
|
