Trifolium stoloniferum - Muhl. ex Eat.
Running Buffalo Clover
Other Common Names: running buffalo clover
Taxonomic Status: Accepted
Related ITIS Name(s): Trifolium stoloniferum Muhl. ex Eat. (TSN 26319)
Unique Identifier: ELEMENT_GLOBAL.2.139222
Element Code: PDFAB40250
Informal Taxonomy: Plants, Vascular - Flowering Plants - Pea Family
 
Kingdom Phylum Class Order Family Genus
Plantae Anthophyta Dicotyledoneae Fabales Fabaceae Trifolium
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Concept Reference
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Concept Reference: Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Concept Reference Code: B94KAR01HQUS
Name Used in Concept Reference: Trifolium stoloniferum
Taxonomic Comments: A distinct species of clover, native to North America.
Conservation Status
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NatureServe Status

Global Status: G3
Global Status Last Reviewed: 29Mar1996
Global Status Last Changed: 27Mar1996
Rounded Global Status: G3 - Vulnerable
Reasons: 104 extant occurrences known, but most populations (72%) are very small, C- or D-ranked occurrences of less than 100 rooted crowns. Nine occurrences (8%) are A-ranked quality with 1000 or more rooted crowns per site (one site in West Virginia with over 100,000 rooted crowns), and 20 occurrencess (20%) are B-ranked quality with between 101-999 rooted crowns. Total estimated number of rooted crowns globally : 106,955. Most historically known sites are extirpated, reducing its known range to small portions of West Virginia, Ohio, Kentucky and Indiana, with one C-RANKed site in Missouri. Ohio, and West Virginia rank this element "S2", Kentucky ranks it "S2S3", and Indiana and Missouri rank it S1. It's habitat is primarily limited to moderately disturbed areas such as old roads, old home sites, cemeteries, jeep trails, etc., which pass through mesic woodlands in regions underlain with limestone (with notable D-RANKed exceptions, e. g. - sandy stream terrace at Cotton Hill, WV), and soils with low Phosphorus content.
Nation: United States
National Status: N3

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Arkansas (SH), Indiana (S1), Kansas (SH), Kentucky (S2S3), Missouri (S1), Ohio (S3), West Virginia (S3)

Other Statuses

U.S. Endangered Species Act (USESA): LE: Listed endangered (05Jun1987)
U.S. Fish & Wildlife Service Lead Region: R3 - North Central

NatureServe Global Conservation Status Factors

Range Extent Comments: Formerly West Virginia to Kansas. Currently extant in limited portions of Indiana, Kentucky, Ohio, Missouri, and West Virginia, especially where underlain by limestones. In Ohio, Kentucky and Indiana, populations are centered around the limestone-underlain region near Cincinnati, and the Inner and Outer Bluegrass regions of northern Kentucky. Only one D-RANKED native population is known from Missouri. In West Virginia, most populations occur within Randolph, Pocahontas, and Barbour Counties, in a mountainous region of the east-central part of the state.

Number of Occurrences: 81 to >300
Number of Occurrences Comments: Estimated extant occurrences as of December, 1995 (at the Running Buffalo Clover information exchange meeting (Cincinnati, Ohio): West Virginia (19), Kentucky (71), Indiana (2), Ohio (12), Missouri (1). Total: 104

Total number of occurrences by Element Ocurrence Quality Rank: A-RANK: 9, B-RANK: 20, C-RANK: 32, D-RANK: 43.

Most of the D-RANK quality occurrences have been found in Kentucky, and a large percentage of them at the Bluegrass Army Depot. At the 1995 Cincinnati meeting, many conservation botanists expressed the opinion that because of the fragility of small populations (with one B-RANK population in Ohio disappearing in one year), primarily A- and B-RANKed occurrences should be considered when determining the number of stable, self-sustainable populations globally.

Population Size Comments: There are an estimated 121,500 rooted crowns at extant, native sites globally, 106,955 in West Virginia, 10,000 in Kentucky, 4,000 in Ohio, 500 in Indiana and 85 in Missouri.

Overall Threat Impact: Very high - high
Overall Threat Impact Comments: Campbell et al (1988) listed several hypotheses for the decline of running buffalo clover: 1) initial habitat destruction by the wave of new settlers, 2) poor dispersal to new sites following the elimination of bison and other large herbivores, 3) loss of the natural grazing regime, 4) increased consumer pressure from increased cattle herds and rabbit populations, 5) increased competition from exotic plants, 6) reduced fire frequency resulting in the loss of open woodlands, and 7) lack of rhizobial infection. At the Running Buffalo Clover Information Sharing Meeting in December of 1995, these hypotheses were reviewed and some participants felt that there was no credible evidence to support numbers 6 & 7 (reduction of fire frequency and lack of rhizobial infection) as a valid cause of the decline of the species. Dr. Michael Vincent expressed concern that there was no solid evidence that these species ever historically had rhizobial associates, and further stated that openings in the canopies to produce woodland habitat for running buffalo clover likely happened with or without fire involvement.

The following suggestions were made at the 1995 Cincinnati meeting regarding current major threats to this species, namely: 1) any irreversible, catastrophic disturbance, such as road construction that completely destroys the habitat and/or kills all plants and seeds within the path of the disturbance, 2) the closing of forest canopies through succession to the point of severe shading, leading to reduced flower and fruit production, 3) loss of habitat through natural or human causes, 4) a reduction of hooved mammals for dispersal of the species' seeds and vegetative fragments, 5) low genetic diversity among populations of T. stoloniferum as reported by Hickey et. al. (1991) and Hickey & Vincent (1992) and Crawford 1995; 6) low population size (less than 30 rooted crowns, or "D-ranked quality" of 41% of the extant occurrences and associated fragility and susceptibility to destruction by vehicle and foot traffic, use of heavy equipment, etc.; 7) a range of viruses that have been observed attacking the species at Missouri Botanical Garden and in introduced populations in Missouri, 8) herbivory by mammals, especially rabbits, groundhogs, etc., 9) fungal diseases, including "tar spot", 10) canopy closure cause too much shade, or canopy removal causing too much sunlight, 11) reduction in a plant pollinator, 12) competition from non-native invasive plant species, especially from Microstegium vimineum, Trifolium repens, and Alliaria petiolata, 13) over grazing, and 14) disruption of moderate prolonged disturbance.

Researchers at that meeting from West Virginia (Harmon, pers. comm.), and Ohio (Windus, pers. comm.) reported the permanent loss of small populations of C- & D-ranked, and one B-ranked quality sites

Until recently, most populations were reported to be small, with plants scattered over an area of several meters (Cusick, pers. comm., Leblanc and Aldrich 1988). Since 1990, 9 large, A-ranked quality sites each with over 1000 rooted crowns present, and 16 B-ranked quality occurrences with 101-1000 rooted crowns present, have been found in West Virginia, Kentucky and Ohio (Harmon 1995, White 1995, Windus 1995). Very small populations are reported to be at high risk of extirpation through physical disruption, disease and inbreeding depression (USFWS 1989).

It has been suggested that T. stoloniferum has a poor dispersal mechanism (Cusick 1989b). According to Cusick, deforestation created many new habitats for the species, but with the loss of bison, elk and eventually deer, there were no effective means of dispersal remaining. White-tailed deer and bison were effectively eliminated from the landscape due to over-hunting. Only recently have deer returned to pre-settlement numbers. According to this theory, habitat in which T. stoloniferum lived, gradually grew closed due to the absence of disturbance by ungulates and fire. Although a presumed primary disperser (deer) is again present, relatively few populations have survived (compared to presettlement numbers of populations.

Jacobs and Bartgis (1987) suggested that along with the destruction of habitat through the clearing of agricultural lands, the introduction of the non-native species, European white clover (Trifolium repens), and bluegrass (Poa pratensis) may have contributed to the decline of this native clover.

D. White (1995) of Kentucky Heritage Program reported that the exotic grass microstegium is a serious threat to many native populations in Kentucky, in that it is strongly competing for resources with running buffalo clover. The white clover is more aggressive and may have invaded the habitat of running buffalo clover, out-competing it for available resources, as well (Jacobs and Bartgis 1987).

Homoya et al. (1989) stated that the removal or suppression of native vegetation by bison [or other large mammals, PJH] may have created the open understory and light gaps necessary for this species. Various researchers at the 1995 meeting in Cincinnati supported the hypothesis that appropriate habitat was more likely produced in presettlement time through canopy gaps created by the falling of large, old-growth trees. Jacobs and Bartgis (1987) suggested that the bison may have provided the right balance of periodic disturbance, soil enrichment, seed dispersal and seed scarification necessary to maintain the clover. It was reasoned that without some level of disturbance, a site would become too shaded to provide enough sunlight for the species (Homoya et al. 1989, Cusick 1989b, Cusick 1988a).

According to Homoya et al. (1989),however, the removal of bison does not completely explain the range-wide depletion of this species. They suggested that there was not a sufficient time interval between bison loss and cattle introduction to account for the rarity now present in the species, since cattle should have satisfied the same biological necessities as bison. However, many researchers currently feel that the ecological equivalency of bison and cattle is uncertain (Vincent, pers. comm., Windus, pers. comm., Harmon, pers. comm.). Davis (1987) likewise disputed the attribution to bison as the cause of the species' decline. In any case, overgrazing by the modern counter-part of the bison, cattle, appears to pose a substantial risk to this species at some sites (Leblanc and Aldrich 1988).

Jacobs and Bartgis (1987) suggested that the decline of this species may have partially centered around a pathogen introduced from the exotic white clover, however no specific disease had been identified at that time. A number of viral and fungal diseases are reported to have attacked the species in greenhouses at Missouri Botanical Garden, including cucumber mosaic virus and the como virus.

The species seems to be a favorite food of some herbivores. At the Missouri Botanical Garden, running buffalo clover plants are habitually gnawed to the ground by rabbits, slugs and other rodents (Pickering 1989). Only protected plants did well. Similar observations have been made in Kentucky (Baskin pers. comm., Davis 1987) and in West Virginia (Foster pers. comm.). It should be noted, however, that herbivores are also the likely dispersers of seeds for this species, so palatable greens are an evolutionary advantage for the species as a whole (M. Vincent, pers. comm.).

Unlike all other species within the genus Trifolium, running buffalo clover lacks a rhizobial associate. Small nodules, uninfected by Rhizobium, have been observed in cultivation, suggesting past associations (USFWS 1989). An experiment has been conducted cooperatively at the Fernow Experimental Forest by the Northeast Forest Experiment Laboratory, the United States Department of Agriculture Agricultural Research Service, Beckeley, West Virginia, and the West Virginia Natural Heritage Program, DNR. Unpublished results suggest that 1) this species does not fix organic nitrogen, 2) that no root nodules of the nature typical of rhizobium infections in other clovers were observed, and 3) that this species seems to respond well to 3 inch clipping. It was stated by Morris, et. al. (1995) that these rusults suggest that T. stoloniferum can tolerate moderate grazing, and is vigorous despite the lack of organic nitrogen fixation.

Land development and the consequential loss of habitat is also a serious concern. In Ohio, urban sprawl around Cincinnati is believed to have destroyed much of the available habitat for this species (Cusick 1987).

Taylor, et. al. (1994) and Hickey, et. al. (1991) cite evidence that inbreding depression may have contributed to the decline of T. stoloniferum. Trifolium spp. native to eastern North America have strong barrier to cross pollination. To a limited degree, T. stoloniferum can set self seed, but inbreeding and loss of vigor were demonstrated by Taylor, et. al. (1994).

Short-term Trend: Relatively Stable (<=10% change)
Short-term Trend Comments: Many historical sites are gone. Species was reportedly frequent in pioneer days (according to historical journals (Campbell, et. al. 1988, Harmon 1990, Cusick 1989b), but many new populations and/or sub-populations have been found in West Virginia, Kentucky, and Missouri since 1990, particularly in areas with soils derived from limestone. Trend data from annual census monitoring is not available from Kentucky, and Indiana, but is from West Virginia, Ohio and Missouri for 3-5 years at most sites. Ohio also has individual population demographic monitoring data that shows that the numbers of rooted crowns in a given sub-populations may vary widely over time, including within a given growing season (Windus, pers. comm.). Since annual census monitoring was begun (around 1989), 6 occurrences have been declared extirpated. One population in Ohio had 250 rooted crowns one year and 0 the next, and the population has not returned to date. Similarly, a sub-population in West Virginia of 31 rooted crowns disappeared one year, returned the next, disappeared the next and has not returned for three years and is considered extirpated.

Intrinsic Vulnerability Comments: Nine large, seemingly healthy populations have been found in West Virginia, Ohio, and Kentucky in which plants are located within the middle of old roads, logging trails, skidder trails, and tank practice areas. Other, smaller sites have been found within dirt roads, old home sites and lawns, cemeteries, picnic grounds, and a few intermittent drains. This suggests that running buffalo clover is a species of moderate periodic disturbance. Severe disturbance that removes vegetation, destroys or deeply buries seeds, or destroys habitat may extirpate a site. Six sites (as of 1995) have been declared extirpated since 1990, particularly where small, D-ranked populations were exposed to direct sunlight and heavy off-road vehicle traffic. A number of these sites in Kentucky, West Virginia, Ohio and Indiana have seemingly disappeared, perhaps due to severe drought and sunlight exposure to D-ranked populations. One B-ranked site in Ohio of 250 rooted crowns disappeared from one growing season to the next (Windus, pers. comm.). The reason for its disappearance is unknown.

Many introduced populations in Missouri have proved infected with fungi, the most damaging being tar spot.

Other NatureServe Conservation Status Information

Distribution
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Global Range: Formerly West Virginia to Kansas. Currently extant in limited portions of Indiana, Kentucky, Ohio, Missouri, and West Virginia, especially where underlain by limestones. In Ohio, Kentucky and Indiana, populations are centered around the limestone-underlain region near Cincinnati, and the Inner and Outer Bluegrass regions of northern Kentucky. Only one D-RANKED native population is known from Missouri. In West Virginia, most populations occur within Randolph, Pocahontas, and Barbour Counties, in a mountainous region of the east-central part of the state.

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map

U.S. & Canada State/Province Distribution
United States AR, IN, KS, KY, MO, OH, WV

Range Map
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U.S. Distribution by County Help
State County Name (FIPS Code)
IN Clark (18019)*, Dearborn (18029), Ohio (18115), Ripley (18137)
KY Bath (21011), Boone (21015), Bourbon (21017), Campbell (21037), Clark (21049), Fayette (21067), Gallatin (21077), Grant (21081), Harrison (21097)*, Jackson (21109), Jefferson (21111), Jessamine (21113), Kenton (21117), Madison (21151), Mason (21161), Mercer (21167), Montgomery (21173), Nelson (21179), Nicholas (21181), Owen (21187), Scott (21209), Woodford (21239)
MO Barry (29009), Benton (29015)*, Boone (29019), Butler (29023)*, Callaway (29027), Carter (29035)*, Cedar (29039)*, Christian (29043)*, Cole (29051)*, Cooper (29053)*, Crawford (29055), Dade (29057)*, Dent (29065)*, Dunklin (29069)*, Howard (29089)*, Jasper (29097)*, Jefferson (29099)*, Laclede (29105)*, Lincoln (29113), Madison (29123), Maries (29125), Moniteau (29135)*, Montgomery (29139), Ozark (29153)*, Phelps (29161), St. Louis (29189), Taney (29213)*, Texas (29215)*, Vernon (29217)*, Wayne (29223)
OH Athens (39009), Brown (39015), Clermont (39025), Hamilton (39061), Hocking (39073), Jackson (39079), Lawrence (39087), Pike (39131), Ross (39141), Vinton (39163), Warren (39165)
WV Barbour (54001), Brooke (54009), Fayette (54019), Greenbrier (54025), Monongalia (54061)*, Pendleton (54071), Pocahontas (54075), Preston (54077), Randolph (54083), Tucker (54093), Webster (54101)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
02 South Branch Potomac (02070001)+
05 Tygart Valley (05020001)+, Upper Monongahela (05020003)+*, Cheat (05020004)+, Upper Ohio (05030101)+, Upper Ohio-Wheeling (05030106)+, Hocking (05030204)+, Greenbrier (05050003)+, Lower New (05050004)+, Gauley (05050005)+, Elk (05050007)+, Lower Scioto (05060002)+, Lower Great Miami (05080002)+, Whitewater (05080003)+, Raccoon-Symmes (05090101)+, Little Scioto-Tygarts (05090103)+, Ohio Brush-Whiteoak (05090201)+, Little Miami (05090202)+, Middle Ohio-Laughery (05090203)+, Licking (05100101)+, South Fork Licking (05100102)+, Upper Kentucky (05100204)+, Lower Kentucky (05100205)+, Rockcastle (05130102)+, Silver-Little Kentucky (05140101)+, Rolling Fork (05140103)+
07 Cuivre (07110008)+, Meramec (07140102)+, Big (07140104)+*
08 Upper St. Francis (08020202)+, Lower St. Francis (08020203)+*
10 Marmaton (10290104)+*, Harry S. Missouri (10290105)+*, Sac (10290106)+*, Lake of the Ozarks (10290109)+*, Upper Gasconade (10290201)+*, Big Piney (10290202)+*, Lower Gasconade (10290203)+, Lower Missouri-Moreau (10300102)+, Lamine (10300103)+*, Lower Missouri (10300200)+
11 Bull Shoals Lake (11010003)+*, North Fork White (11010006)+*, Upper Black (11010007)+, Current (11010008)+*, Spring (11070207)+*, Elk (11070208)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: Perennial herbaceous vascular plant with creamy-white flower heads and leaves divided into three rounded leaflets, similar in appearance to the familiar Dutch clover of suburban lawns. Flowers mid-May through early June; flowering stems 1-4 dm tall.
Technical Description: Perennial with ascending flowering stems 1-4 dm. high, sending out long basal runners; flowering stem scapose below, with 2 large leaves near the summit, their stipules with ovate-oblong blades, their obovate leaflets 2.5-4.5 cm long; leaves of the runners with lanceolate stipules and mostly smaller leaflets; peduncles short, from the upper axils; heads subglobose, 2.5-3.5 cm. in diameter; calyx-teeth twice as long as the glabrous tube; corolla white, tinged with purple, exceeding calyx (Fernald, 1950).
Diagnostic Characteristics: T. stoloniferum (Running Buffalo Clover): Stems upright, not branching from the base; creeping runners (stolons) also arising from the base; white flower heads arising from a pair of aerial leaves; entire plant 4-20 inches high. T. repens (Dutch Clover): Stems prostrate, creeping; white flower heads on naked stems arising directly from the creeping stems; flower stalks 2-8 inches long. T. reflexum (Buffalo Clover): Stems upright, branching from the base; flower heads pinkish or occasionally white, arising from a pair of aerial leaves, entire plant 4-19.5 inches high (Comparative data developed by Ohio Dept. Natural Resources)
Duration: PERENNIAL
Reproduction Comments: Thought to have been dispersed by buffalo (bison) at one time. This clover is believed to be self-fertile (Jacobs and Bartgis 1987). Seed production is generally good, even after self-pollination, with a well-developed head of 20-40 flowers producing at least 10-20 seeds (Campbell et al. 1988). After initiation of spring flowering, stolon growth is most vigorous (USFWS 1989). Stolons have been known to grow as much as 70 cm per season in greenhouse conditions (Campbell et al. 1988). Stolons typically root at the nodes that touch soil.
Known Pests: EAGERLY SOUGHT BY HERBIVORES
Ecology Comments: Trifolium stoloniferum blooms from mid-May through early June in Ohio (Cusick 1989b, 1988a). Due to the close proximity to all other known locations for the species, little variance should be noted with respect to flowering periods. Thurman (1988) does suggest, however, that the flowering period may vary with respect to yearly fluctuations in precipitation. Flowering is induced by exposure to temperatures varying between 30-40 degrees Fahrenheit or less (Campbell et al. 1988).

Running buffalo clover is believed to be self-fertile (Jacobs and Bartgis 1987). Seed production is generally good, even after self- pollination, with a well-developed head of 20-40 flowers producing at least 10-20 seeds (Campbell et al. 1988). After initiation of spring flowering, stolon growth is most vigorous (USFWS 1989). Stolons have been known to grow as much as 70 cm per season in greenhouse conditions (Campbell et al. 1988). Stolons typically root at the nodes that touch soil.

Propagation research in Kentucky (Campbell et al. 1988) showed that scarification of the seeds is apparently essential for germination. In the study, little or no germination was observed in unscarified seeds, while 90%-100% germination was noted for scarified seeds. Scarification of seeds by the digestive system of herbivores, historically believed to be bison, deer (Cusick 1988a, Thurman 1988) or rabbits, was likely a major event in natural populations (Cusick pers. comm., 1989b). In post-settlement times, cattle have replaced the bison (Pickering 1989). This scarification process is believed to be important for germination and as a means of seed dispersal. Cusick (1989b) observed that plants are frequently found in clumps of four to five individuals, indicating deposition of seeds in the feces of deer. Mechanical scarification through trampling by ungulates or action of rivers may also have occurred, but was probably infrequent.

Recent research by Carol and Jerry Baskin at the University of Kentucky has shown that spring temperature fluctuations appear to be a major dormancy breaker in natural populations of T. stoloniferum (Baskin pers. comm.). Seeds possess a specific site near the strophiole (near the hylem) that becomes permeable to water during certain temperature regimes (Baskin pers. comm.). Unscarified seeds typically germinate during early spring (mid- March to early April) when temperatures are between 15 and 20 degrees Celsius during the day and 5-10 degrees Celsius at night. A long-term study has shown that roughly 60% of the seeds that were initially planted have germinated over a span of three years.

There appears to be little genetic diversity between populations of T. stoloniferum, although no electrophoretic tests have been conducted (Taylor pers. comm.). At the University of Kentucky, individual plants from different locations have been grown at different temperatures. At low temperatures, different leaf markings are exhibited among plants, indicating that there is some degree of genetic diversity in the species (Taylor pers. comm.).

Rhizobial infections are unknown in this species. Populations in Kentucky, West Virginia (Campbell et al. 1988), and Indiana (Leblanc and Aldrich 1989) have been studied, but a rhizobial agent has not been found. Similarly, current research at the USDA Appalachian Soil and Water Conservation Research Laboratory has not been able to find existing inoculants (Foster pers. comm.). Packard (pers. comm.) stated that the lack of Rhizobium associated with running buffalo clover may suggest that extant populations are merely waifs of larger populations in historic habitats (Packard pers. comm.). The few recently discovered "waif" populations may be in disturbed situations today only because their principle habitat (savanna) has been destroyed. It is unknown whether the loss of Rhizobium is a result of the decline of the clover, or if its loss contributed to the clover's decline (Leblanc and Aldrich 1988).

A second hypothesis is that T. stoloniferum may never have required the rhizobial infection, and did not, consequently, retain the associate. Soybeans, another legume, are well-known for the fact that they do not form root nodules when nitrogen levels are high. Trifolium stoloniferum may have a low Nitrogen requirement and therefore never developed the need for a rhizobial associate. In fact, T. stoloniferum appears robust and healthy in many situations even without such an associate (Bloom pers. comm.).

The possible insect pollinators of this species are unknown and have not been studied (Cusick 1988a). Honeybees have been used for pollination in greenhouse situations at the University of Kentucky by Norman Taylor (Taylor pers. comm.). The species is able to produce seeds through selfing. N-fixing nodules were observed on old specimens; recently discovered stands appear to lack these.

Terrestrial Habitat(s): Forest - Hardwood, Forest/Woodland, Grassland/herbaceous, Savanna, Suburban/orchard, Woodland - Hardwood
Habitat Comments: Running buffalo clover's habitat most commonly is mesic woodlands in partial to filtered sunlight, where there is a pattern of moderate periodic disturbance for a prolonged period, such as mowing, trampling, or grazing. It is most often found in regions underlain with limestone or other calcareous bedrock, but not exclusively. It has been reported from a variety of disturbed woodland habitats, including blue-ash savannahs, floodplains, streambanks, shoals (especially where old trails cross or parallel intermittent streams), grazed woodlots, mowed paths (e.g. cemeteries and lawns), old logging roads, jeep trails, skidder trails, mowed wildlife openings within mature forests, and steep, weedy ravines.

Packard (pers. comm.) suggested that the original habitat may have been open woods or savannah. Trifolium stoloniferum was thought by some (Campbell, et. al., 1988; Cusick 1989a) to have been somewhat dependent on the once-common buffalo (Bison bison bison), [or elk or deer] for seed scarification and dispersal, and for the maintenance of its moderately disturbed habitat. J. Campbell (pers. comm., Campbell, et. al. 1988) described the species' native habitat in Kentucky as "blueash savannah". However, many researchers present at the 1995 Cincinnati meeting felt that this species was not likely originally a species of savannah in the sense of that associated with the tall grass prairies, say of Illinois, as much as open woodland, also having filtered sunlight, but having less competition from herbaceous prairie species.

Economic Attributes
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Economically Important Genus: Y
Economic Comments: Being studied experimentally by Univ. Kentucky for possible forage value, and possible hybridization with commercial clovers. However, nitrogen-fixing microbial associate currently not known extant. Experimental innoculations with other N-fixing bacteria have reportedly failed.
Management Summary
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Stewardship Overview: Monitoring should be centered around the tracking of population dynamics, habitat, management practices and other potential problems over time. Priority research areas include determining the true status of the species throughout its range using the latest search images, development of appropriate management techniques, continued search for a rhizobial associate, determining the species potential as a forage crop, and developing adequate reintroduction methodologies. Management needs include the maintenance of partially open canopies, the use of appropriate mowing regimes to enhance flower and seed production but reduce competition, and the potential use of light grazing and/or fire as management tools in mimicking presettlement conditions.
Restoration Potential: Two plants have been removed from a West Virginia site to a greenhouse at the University of Kentucky for study by Julian Campbell and Norman Taylor (Davis 1987, Bartgis 1985). Plants in cultivation have produced many offspring, vegetatively, and by seed (Jacobs and Bartgis 1987), yielding information about its habits and requirements. In 1986, offspring of these plants were transplanted to National Park Service land (at eight separate sites) and the Core Arboretum, both in West Virginia (Jacobs and Bartgis 1987).

Reintroduction efforts on National Park Service land have not fared well due to competition from other plants, particularly Glechoma hederacea, seven of eight introduced populations have died. Other offspring of these cultivated plants have been transplanted to a number of research institutions, including a USDA Appalachian Soil and Water Conservation Research Lab in Beckley, West Virginia, the West Virginia University in Morgantown, West Virginia, and the U.S. National Arboretum in Washington, D.C. (McDonald 1987-1988).

The Missouri Botanical Garden has acquired plants from several sites and is cooperating with Julian Campbell of the Kentucky Field Office of The Nature Conservancy to build cultivated populations (Pickering 1989).

Singha et al. (1988), of West Virginia University, were recently able to rapidly propagate running buffalo clover via tissue culture on Murashige and Skoog (MS) medium. Currently, other propagation tests are being conducted in Kentucky (Campbell et al. 1988).

Jacobs and Bartgis (1987) stated that causes for the decline of the species must be pinpointed before recovery can proceed. Limited genetic variability among cultivated and wild populations may prove to be a serious problem in propagating this species (Jacobs and Bartgis 1987).

Preserve Selection & Design Considerations: Trifolium stoloniferum is associated with stream-side and upland communities within its range. As a result, land protection specifications need to reflect these differing habitats.

Upland sites are typically associated with lawns, although some populations are also known from open woodlands. In lawns surrounding private houses, it may be difficult to adequately protect the site as if a nature preserve. Working protection plans should be sought with the landowners so that there exists sufficient buffer around extant populations to enhance long-term survival. Appropriate management regimes must also be implemented.

Sites within open woodlands, regardless of whether they occur on floodplains or not, should be sought for possible acquisition. Due to the extreme rarity of the species, all sites are considered important for recovery efforts. Protection of upstream watersheds is necessary to prevent or lessen the threat of serious flooding, habitat destruction and herbicide run-off.

Management Requirements: An improvement in the methodology for maintaining and enlarging the cultivated lines should be developed (USFWS 1989). This study should be implemented after the need for long-term maintenance of genetic lines has been determined through isozyme analysis (USFWS 1989). Research on both of these aspects is being conducted at the present time.

Even though much of the life-history of running buffalo clover has yet to be fully researched, enough information is known to suggest that active management might be necessary for this species. Management may need to include propagation, reintroduction, habitat maintenance and manipulation, predator and competitor control, depredation control, disease control and public information (USFWS 1989).

Management of habitat should maximize the viability of extant T. stoloniferum populations, and needs to, therefore, tread a thin line between too little and too much disturbance (Cusick 1989b, 1988a). Present beliefs seem to favor the use of herbivores, mowing regimes (Homoya et al. 1989) or prescribed fire (Packard pers. comm., Thurman 1989) as management tools in order to agitate soil and/or keep woodlands open. Each management regime should be practiced on a small scale in order to determine its effectiveness. Management practices at reintroduction sites should be similar to those used for wild populations (USFWS 1989).

Since a large proportion of remaining populations occur in old, ill-kept lawns (i.e., possessing many broadleaf weeds), mowing regimes are important in controlling alien weedy species, particularly Japanese honeysuckle (Lonicera japonica) and garlic-mustard (Alliaria petiolata) (Cusick 1989b). Mowing should be suspended in early May to allow for flowering, and resumed in mid July after seed set.

Although there is a controversy regarding whether fire played an important role in the formation of the Kentucky Bluegrass savannas, there seems to be little doubt that fire was at least a partial factor in maintaining them. If the adjacent Big Barrens of Kentucky were kept open by fire set by Native American Indians (Baskin and Baskin 1978), it is not too large a step to suspect that the same was true for the Bluegrass region. If these savannas were kept open by large herds of grazing ungulates (Bison and elk), Native American Indians would have been attracted to these areas as well, employing the same methodologies of concentrating game by fire that were used on the prairies and plains.

Management should be centered around the attempt to conserve the known genotypes through seed storage, maintenance of existing cultivated lines and cultivation of plants from wild populations (USFWS 1989).

For populations occurring in lawns, mowing of T. stoloniferum plants should be delayed between flower bud formation and seed dehiscence (typically from early May to mid July) (Cusick 1988a). During this period, mower blades can be set at higher levels in order to reduce the effects caused by competition with other herbaceous species.

Prescribed burning methodologies should be considered on an experimental basis with T. stoloniferum. At present, no data exist with respect to the impact fire can have on the species, beneficial or otherwise. Restoration of presettlement habitat may need to be considered if T. stoloniferum is to thrive under natural management regimes. Suggested management guidelines for this species, based upon current research data, have been developed by Jennifer Windus (Ohio Division of Natural Areas and Preserves). Other management needs include the maintenance of partially open canopies and control of foot and vehicle traffic and grazing.

Monitoring Requirements: Due to the extremely low number of known individuals of this species, monitoring of population dynamics (Homoya pers. comm.), habitat, and potential problems such as exotic plants should be undertaken. Specific management practices for the species have been proposed, and if implemented, should also be monitored. Although individual counts would suffice in terms of providing useful information on population size, the mapping and marking of individuals should provide detailed information regarding recruitment and mortality over time. Pisspia (pers. comm.) suggested that population monitoring would provide more useful data if permanent plots were established in which individual plants were marked and followed through time. The added time expense involved in such a monitoring program should be warranted due to the extreme endangerment of the species. Prior to the initiation of population monitoring, it must be decided as to what constitutes an individual. Do juvenile plants, still connected via stolon to the parent plant, constitute distinct individuals?

Census monitoring should be conducted annually in May through June, when flowers are peaking and when there will be mother crowns developing and stolon growth occurring. Flower production and seed set within a population should also be monitored. Individual counts of flower numbers per individual as well as the presence of seed should be noted annually.

Monitoring should also take into account the habitat in which the species currently lives. Estimates of canopy cover and cover by associated shrub and ground layer species should also be tracked through time. Monitoring of exotic plants should be installed in order to detect changes that may harm the existing populations.

Lawn management for the benefit of T. stoloniferum should be maintained at all sites occurring on lawns. Mowing intervals, herbicide application and other tradition methods of upkeep should be monitored to insure the survival of the species at these sites.


Management Programs: The Missouri Department of Conservation is planning to request Recovery 2000 funds from the USFWS to establish a population of T. stoloniferum in the state (Thurman pers. comm.). Contact: Tim Nigh, Missouri Natural Heritage Program, Missouri Department of Conservation, P.O. Box 180, Jefferson City, MO 65102. Telephone No. (314) 751-4115.

The Ohio State Historical Society has agreed to forego the mowing of a cemetery in which running buffalo clover occurs until after the plant has fruited (Cusick 1989a). Initial results of this action show a four-fold increase in individual numbers in 1989 over what was observed the previous year. A management plan between the Ohio Division of Natural Areas and Preserves and the Ohio State Historical Society will be worked out this winter (1989-1990). Contact: Allison Cusick, Chief Botanist, Ohio Natural Heritage Program, Ohio DNR, Division of Natural Areas and Preserves, 1889 Fountain Square, Building F-1, Columbus, OH 43224. Telephone No. (614) 265-6471.

The National Park Service has apparently maintained its commitment to reintroduced plants on its land in West Virginia (Weesner pers. comm.) by planning to spend additional time on management and further reintroduction of propagated plants. Contact: Meg Weesner, Natural Resource Specialist, National Park Service, New River Gorge National River, 137 1/2 Main Street, P.O. Box 1189, Oak Hill, WV 25901. Telephone No. (304) 465-0508.

Bender (pers. comm.) stated that private landowners in Kentucky are willing to protect the existing populations and reduce the risk of damage through mowing. Plants will be marked prior to flowering in 1990 so that T. stoloniferum plants will not be mowed when they are in flower or in fruit. Contact: Joyce Bender, Kentucky Heritage Program, Kentucky Nature Preserves Commission, 407 Broadway, Frankfort, KY 40601. Telephone No. (502) 564-2886.

Monitoring Programs: Ohio, West Virginia (McDonald 1987-1988), and Indiana have all implemented monitoring programs for known running buffalo clover populations. Kentucky has also agreed to monitor ten representative populations in the state. Missouri has agreed to monitor its one naturally occurring site. States agreed to count just rooted crowns, not plants, for the annual census monitoring. If there are more than 50 rooted crowns, monitors are to count all rooted crowns, but if there are more than 50 rooted crowns presents at a given site, one is to count the number of rooted crowns in a square meter plot (best done by using wire flags set at each rooted crown and counting the flags), then extrapolating to the ara covered by the population being sampled. Researchers are to record how they got their data. If there is more than one subpopulation in a given ocurrence, monitors are to sample each subpopulation via the square meter plot method, and extrapolate to get estimates of each subpopulation. Monitoring is to be conducted for at least 3-5 years beginning in 1996. States are to share monitoring data as it is collected with other states and other interested parties. Other monitoring projects that should be conducted in states where funds and personnel are available (e. g. - Ohio) include population dynamics, habitat changes (e.g. succession, extreme disturbance), management practices and other potential impacts over time. In Ohio, contact: Allison Cusick, Division of Natural Areas and Preserves, DNR, Fountain Square, Bldg. F, Columbus, Ohio 43224. Telephone No. (614) 265-6453. In Indiana, contact: Mike Homoya, Botanisht, Indiana Heritage Program, DNR, 605b State Office Building, Indianapolis, IN 46204. Telephone No. (317) 232-4052. In West Virginia, contact: P.J. Harmon, Botanist, West Virginia Natural Heritage Program, Dept. of Natural Resources, P.O. Box 67, Elkins, WV 26241. Telephone No. (304) 636-1767. Contact: Joyce Bender or Tom Bloom, Kentucky Heritage Program, Kentucky Nature Preserves Commission, 407 Broadway, Frankfort, KY 40601. Telephone No. (502) 564-2886.
Population/Occurrence Delineation Not yet assessed
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Population/Occurrence Viability
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Excellent Viability: Population has 1,000 or more naturally occurring rooted crowns. Plants occur in natural suitable habitat (mesic woodland or river terraces) where the disturbance regime is maintained by natural processes (such as large mammal trampling, canopy gap creation, stream scouring); OR in somewhat suitable habitat maintained by anthropogenic activities (old roads, jeep trails, ?skidder? trails) where disturbance for a prolonged period (such as grazing, trampling, light logging traffic) is mild to moderate.
Good Viability: Population has between 100 and 999 naturally occurring rooted crowns. Plants occur in suitable habitat (mesic woodland, river terraces, or partially shaded lawn) where the disturbance regime is maintained by natural processes (such as large mammal trampling, canopy gap creation, stream scouring); OR in somewhat suitable habitat maintained by anthropogenic activities (old roads, jeep trails, ?skidder? trails, old cemeteries, savannah-like lawns at old home sites) where disturbance for a prolonged period (such as mowing, grazing, trampling, or logging)is mild to moderate.
Fair Viability: Population has between 30 and 99 naturally occurring rooted crowns. Plants occur in suitable habitat (mesic woodland, river terraces, or partially shaded lawn) where the disturbance regime is maintained by natural processes (such as large mammal trampling, canopy gap creation, stream scouring); OR in somewhat suitable habitat maintained by anthropogenic activities (old roads, jeep trails, ?skidder? trails, old cemeteries, savannah-like lawns at old home sites) where disturbance for a prolonged period (such as mowing, grazing, trampling, or logging) is curtailed or limited.
Poor Viability: Population has between 1 and 29 naturally occurring rooted crowns. Plants occur in suitable habitat (mesic woodland, river terraces, or partially shaded lawn) where the disturbance regime is maintained by natural processes (such as large mammal trampling, canopy gap creation, stream scouring); OR in somewhat suitable habitat maintained by anthropogenic activities (old roads, jeep trails, ?skidder? trails, old cemeteries, savannah-like lawns at old home sites) where disturbance for a prolonged period (such as mowing, grazing, trampling, or logging) is curtailed or limited.
U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 16Jan1997
NatureServe Conservation Status Factors Author: Harmon, P. J. (1997)
Management Information Edition Date: 01Jan1990
Management Information Edition Author: WAYNE OSTLIE
Element Ecology & Life History Edition Date: 30Jun1989

Botanical data developed by NatureServe and its network of natural heritage programs (see Local Programs), The North Carolina Botanical Garden, and other contributors and cooperators (see Sources).

References
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  • Bartgis, R.L. 1985. Rediscovery of Trifolium stoloniferum Muhl. ex A. Eaton. Rhodora 87: 425-429.

  • Baskin, J.M., and C.C. Baskin. 1978d. The Big Barrens of Kentucky not a part of Transeau's Prairie Peninsula. Pp. 43-48 in: The Prairie Peninsula - In the Shadow of Transeau. Proceedings of the Sixth North American Prairie Conference.

  • Bloom, T. 1989. Field Survey for running buffalo clover (Trifolium stoloniferum Muhl. ex A. Eaton) Project E-1-3 Report, USFWS, Atlanta, Georgia. 31 pp.

  • Braun, E. L. 1950. Deciduous forests of eastern North America. The Blakiston Co., Philadelphia.

  • Brooks, R. E. 1983a. Trifolium stoloniferum, running buffalo clover: Description, distribution, and current status. Rhodora 85: 343-354.

  • Brooks, R. E. 1983b. Neotypification of Trifolium stoloniferum Muhl. ex A. Eat. (Fabaceae). Taxon 32: 454-455.

  • Campbell, J.J., M. Evans, M.E. Medley, and N.L. Taylor. 1988. Buffalo clovers in Kentucky (Trifolium stoloniferum and T. reflexum): historical records, presettlement environment, rediscovery, endangered status, cultivation and chromosome number. Rhodora 90(864): 399-418.

  • Cusick, A. W. 1988a. 1988 Ohio status survey for Trifolium stoloniferum, running buffalo clover. Unpublished Ohio Department of Natural Resources, Columbus, contract to USFWS, Twin Cities, Minnesota. 35 pp.

  • Cusick, A. W. 1989a. Running buffalo clover in Ohio: 1989 status report. Unpublished report to the USFWS, Twin Cities, Minnesota. 2 pp.

  • Cusick, A. W. 1989b. Trifolium stoloniferum (Fabaceae) in Ohio: History, habitats, decline, and rediscovery. Sida 13(4): 467-480.

  • Davis, W. H. 1987. On the decline of Trifolium stoloniferum. Kentucky Native Plant Soc. Newsletter 2(3): 10.

  • Homoya, M.A., J.R. Aldrich, and E.M. Jacquart. 1989. The rediscovery of the globally endangered clover, Trifolium stoloniferum, in Indiana. Rhodora 91(866): 207-212.

  • Jacobs, J. 1987. Running buffalo clover discovered at new sites. Endangered Species Technical Bull. 12(9): 4.

  • Jacobs, J.F., and R.L. Bartgis. 1987. The running buffalo clover. In R.D. Silvestro (ed.), Audubon Wildlife Report, 1987. Academic Press, Orlando, FL.

  • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

  • Leblanc, C. M., and J. R. Aldrich. 1988. Report on the status of Trifolium stoloniferum in Indiana. Unpublished Indiana Department of Natural Resources report, Indianapolis. 18 pp.

  • McDonald, B. R. 1988. Running buffalo clover recovery performance report. Unpublished West Virginia Natural Heritage Program report, Elkins, West Virginia. 13 pp.

  • Pickering, J. 1989. Conservation efforts boost hopes for rare clover. The Center for Plant Conservation 4 (2): 3.

  • Schwegman, J. E. 1988. Results of a search for running buffalo clover (Trifolium stoloniferum) in Illinois. Unpublished report prepared by the Illinois Department of Conservation. 5 pp.

  • Singha, S., B. S. Baker, and S. K. Bhatia. 1988. Tissue culture propagation of running buffalo clover (Trifolium stoloniferum Muhl. ex A. Eaton.) Plant Cell, Tissue, and Organ Culture 15: 79-84.

  • Thurman, C. M. 1988. Report on the search in Missouri for running buffalo clover: Trifolium stoloniferum. Unpublished report prepared for the Missouri Department of Conservation and the USFWS. 21 pp.

  • U.S. Fish and Wildlife Service. 1987. Determination of endangered status for Trifolium stoloniferum (running buffalo clover). Federal Register 52(108): 21478-21481.

  • United States Fish and Wildlife Service. 1986. Three plant taxa proposed for protection. Endangered Species Tech. Bull. 11 (4): 3-4.

  • United States Fish and Wildlife Service. 1989. Trifolium stoloniferum recovery plan. USFWS, Twin Cities, Minnesota. 26 pp.

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