Regularity: Regularly occurring
Global Range: Regional endemic, western Indiana and southern Wisconsin to Illinois, Iowa and Missouri. No recent information from Michigan; historical but not known extant in Arkansas.
Comments: Ranges from woods and edges to railroad rights of ways; moist, north-facing rocky ledges and stream bluffs, and open oak woods.
Tans and Read (1975) describe A. furcatus as a regional endemic with a diversity of habitats ranging from woods and edges to railroad rights of way. Extant populations are found on moist rocky ledges, north-facing stream bluffs, open oak woods, and north-facing wooded slopes (Barloga, Bowles, Ewert, McGrath, Morgan, pers. comm.).
In Illinois, the substrate can be sandy soils or glacial till on bluffs with Betula papyrifera, Osmunda cinnamomea and Symplocarpus foetidus growing in association (Bowles, pers. comm.). In Indiana, forked aster is found on the sides and edges of narrow sandstone gorges in thin organic soil. The presence of Parnassia glauca along the gorges indicates that some calcareous material must be present in the soil (McGrath, pers. comm.). A. furcatus has been found on a sandy ridge in open oak woods in Iowa (Ewert, pers. comm.).
Large populations have been found in seepy soils at the base of north-facing dolomite bluffs along rivers in Missouri (Morgan, pers. comm.). Trautvetteria caroliniensis occurs with forked aster at many of the Missouri sites (Leoschke, pers. comm.). In Wisconsin, the plant has been found on top of a north-facing clay bluff at the edge of a Quercus rubra - Ostrya virginiana woods and at the base of the bluff along the Menomonee River (Barloga, pers. comm.). Associates in Wisconsin include Aster lateriflorus, Solidago flexicaulis, and Jeffersonia diphylla.
Flower-Visiting Insects of Forked Aster in Illinois
(Bees suck nectar or collect pollen, flies suck nectar or feed on pollen, beetles feed on pollen, other insects suck nectar; all observations are from Graenicher)
Apidae (Apinae): Apis mellifera sn; Apidae (Bombini): Bombus vagans sn cp; Anthophoridae (Anthophorini): Anthophora terminalis sn; Anthophoridae (Ceratinini): Ceratina dupla dupla sn; Anthophoridae (Epeolini): Triepeolus pectoralis sn; Anthophoridae (Nomadini): Epeoloides pilosulla sn; Anthophoridae (Xylocopini): Xylocopa virginica sn cp; Megachilidae (Coelioxini): Coelioxys modesta sn, Coelioxys octodentata sn, Coelioxys sayi sn; Megachilidae (Megachilini): Megachile centuncularis cp, Megachile mendica sn, Megachile montivaga sn; Megachilidae (Osmiini): Osmia atriventris sn
Halictidae (Halictinae): Agapostemon sericea sn, Augochlora purus sn, Augochlorella striata sn cp, Halictus spp. sn cp, Halictus confusus sn cp, Halictus rubicunda sn cp, Lasioglossum albipennis sn, Lasioglossum coriaceus sn cp, Lasioglossum imitatus sn cp, Lasioglossum versatus sn, Lasioglossum zephyrus sn; Halictidae (Sphecodini): Sphecodes minor sn; Colletidae (Colletinae): Colletes eulophi sn; Colletidae (Hylaeinae): Hylaeus mesillae sn, Hylaeus modestus modestus sn; Andrenidae (Andreninae): Andrena hirticincta sn cp olg, Andrena nubecula sn cp olg, Andrena peckhami sn cp; Andrenidae (Panurginae): Calliopsis andreniformis sn; Melittidae: Macropis nuda sn
Sphecidae (Crabroninae): Ectemnius lapidarius, Ectemnius trifasciatus; Sphecidae (Larrinae): Tachytes pepticus; Sphecidae (Sphecinae): Ammophila kennedyi; Ichneumonidae: Ichneumon laetus; Vespidae: Dolichovespula arenaria, Polistes fuscata, Vespula vidua; Vespidae (Eumeninae): Ancistrocerus adiabatus, Ancistrocerus catskill, Eumenes fraterna, Euodynerus foraminatus, Parancistrocerus vagus
Bombyliidae: Exoprosopa fascipennis; Syrphidae: Eristalis arbustorum, Eristalis dimidiatus, Eristalis flavipes, Eristalis tenax, Eristalis transversus, Helophilus fasciatus, Helophilus stipatus, Ocyptamus fascipennis, Syritta pipiens, Toxomerus geminatus, Toxomerus marginatus, Tropidia quadrata, Volucella bombylans; Tachinidae: Archytas analis, Cylindromyia carolinae, Cylindromyia dosiades, Gymnoclytia immaculata, Tachinomyia panaetius; Sarcophagidae: Sarcophaga sarracenioides; Calliphoridae: Lucilia illustris; Muscidae: Graphomya maculata, Stomoxys calcitrans
Nymphalidae: Danaus plexippus, Limenitis arthemis astyanax, Phyciodes tharos; Pieridae: Colias philodice, Pieris rapae; Lycaenidae: Celastrina argiolus, Satyrium calanus
Hesperiidae: Ancyloxypha numitor
Ctenuchidae: Cisseps fulvicollis; Noctuidae: Mythimna unipuncta
Mordellidae: Hoshihananomia octopunctata fp
Alydidae: Megalotomus quinquespinosus; Miridae: Lygus lineolaris; Pentatomidae: Euschistus tristigma
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 21 - 80
Comments: Several in Iowa (2, 1 county), Illinois (20), Indiana (14, 4 counties), Wisconsin (25), and Missouri (37, 6 counties, however, 30 of 37 EO's occur in a single county).
Forked aster is a perennial with a creeping rhizome. The plants are very local (Bowles, Menges, pers. comm.). New shoots can arise vegetatively from the tips of rhizomes. Each plant produces a rhizome which elongates and then puts down roots. A new shoot will arise at this site along the rhizome (Lamboy, pers. comm.). Asexual reproduction from the rhizome produces dense colonies of forked aster that can be several feet in diameter (Shinners, 1941). A. furcatus is one of the earliest asters to bloom, starting in July in Missouri (Steyermark, 1977). Plants will flower only if they have stored up an adequate carbohydrate reserve during the year. Dense shade inhibits carbohydrate production which in turn will inhibit both flower production and rhizome growth (Lamboy, pers. comm.).
Seed production at one Wisconsin site is good (Barloga, pers. comm.), but two separate populations are usually required for heavy seed production (Stovall and Cole, 1983). In dense, isolated populations that are thought to be clonal, Lamboy (pers. comm.) reports one percent or fewer full (presumed viable) achenes from selfing. Pollen from other aster species present on an A. furcatus stigma reacts chemically and breaks down the barrier inhibiting the germination of the plant's own pollen grains.
Seed production is not thought to be as important as vegetative reproduction for population maintenance (McGrath, pers. comm.). In his research on A. acuminatus, a species with similar habitat requirements, Pitelka (pers. comm.) reports that reproduction from seed is rare in an established patch because seedling establishment is disturbance associated. Aldrich (pers. comm.) mentions that seedlings of A. furcatus may establish at river bank sites after the river has scoured the banks and eliminated competition. When conditions are favorable for seed germination, plants will mature two years after germinating and will begin to produce flowers if carbohydrate reserves are adequate.
National NatureServe Conservation Status
Rounded National Status Rank: N3 - Vulnerable
NatureServe Conservation Status
Rounded Global Status Rank: G3 - Vulnerable
Reasons: Regional endemic of the Midwest with dozens of occurrences, some with large number of individuals.
Global Short Term Trend: Relatively stable to decline of 30%
Comments: Declining primarily from loss of habitat to development.
Comments: Threats include: loss of habitat through urbanization; alteration of habitat, i.e. change in water flow through seeps, collapse of bluffs and rock falls; total canopy removal for power line right-of-way (Watson, 1983); impacts of recreation on riverbank populations; the absence of disturbance processes necessary for establishhment; and overshading by canopy closure which reduces flowering and clonal expansion (Ashmun and Pitelka, 1984).
Restoration Potential: Natural recovery potential is uncertain. Indications are good that depleted sites can be restocked. Steyermark (1977) has grown forked aster in a shaded wildflower garden. Jones (Lamboy, pers. comm.) has cultivated the plant in full sun with good results. Lamboy (pers. comm.) notes that A. furcatus transplants well and that one plant can spread dramatically. Seeds have been germinated on wet filter paper with varying results. Breaking dormancy may take two to three weeks or two to three months (Lamboy, pers. comm.).
Preserve Selection and Design Considerations: Purchase enough buffer to ensure protection of the canopy and water flow in seepy areas. If runoff from areas upslope have the potential to erode the bluff or cause siltation, purchasing more of the watershed may be required for effective runoff control. Obtain protection agreements for sites on privately owned land.
Management Requirements: The reduced light levels brought on by canopy closure may prove to be harmful to the reproductive ability of A. furcatus (Lamboy, pers. comm.). Specifically, relatively high light levels are thought to be important to stimulate flower production and are associated with other factors believed to be necessary for seedling establishment. Clonal expansion through rhizomatous growth is also dependent on light levels for nutrients supplied by carbohydrate production.
The thin soil and wet conditions along rocky bluffs may keep woody vegetation from encroaching, but each site should be evaluated for management needs.
Wilhelm (pers. comm.) suggests fire as a management tool based on his impressions of the habitat in the midwest prior to settlement. If fire is not practical, he also suggests removing the heavy shade trees in the canopy, e.g. Acer spp.
Biological Research Needs: Establish a correlation between plant age and number of stems to provide consistency in assessing population demography in the field. [(1987)Information on all phases of the life cycle especially factors critical for sexual reproduction and seedling establishment. Characterizing the properties of the water chemistry may provide useful information on habitat requirements at the seepage sites. SEE LES ET AL, 1991 and LES ET AL, 1992]
Relevance to Humans and Ecosystems
Stewardship Overview: Monitor to track changes in population size, clonal expansion, and new recruitment into populations. Monitoring flower production and corresponding canopy cover may provide some suggestive correlations on the role of light on reproductive vigor. A high priority for research is studies into the factors critical for sexual reproduction and seedling establishment. Characterizing the properties of the water chemistry may provide useful information on habitat requirements at the seepage sites. It is not known if management to manipulate canopy cover or to scarify the substrate is advisable, but on small sites where the natural occurrence of such disturbance is infrequent or absent, such habitat manipulation may be important for long-term population viability. The role of fire is also unclear, but it is presumed that in sites where fires naturally occurred, fire would have a neutral to beneficial influence.
Eurybia furcata, commonly called the Forked Aster, is an herbaceous perennial in the composite family. It is native to areas west of the Appalachian Mountains, but east of the Great Plains in the United States. It is uncommon throughout its range, and occurs in the states of Michigan and Wisconsin in the north, south through Nebraska, Illinois and Indiana, and into Missouri and Arkansas. The species is intolerant of shade and is typically found on rocky, north-facing slopes, especially those composed of limestone, dolomite, or sandstone. It can also be found in seeps on bluffs, in moist woods along streams, and occasionally in disturbed sites. It is included in the Center for Plant Conservation’s National Collection of Endangered Plants.
- ^ NatureServe (2006), "Eurybia furcata", NatureServe Explorer: An online encyclopedia of life, Version 6.1., Arlington, Virginia, http://www.natureserve.org/explorer/servlet/NatureServe?searchName=Eurybia+furcata+
- ^ Brouillet, Luc (2006), "Eurybia furcata", in Flora of North America Editorial Committee, eds. 1993+, Flora of North America, 20, New York & Oxford: Oxford University Press, pp. 372, http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250066749
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