Some authors list A. burdickii as a separate species, but most evidence supports a single species with two subspecies: A. tricoccum ssp. tricoccum and A. tricoccum ssp. burdickii (Bell 2007).

Allium tricoccum (Ramp) is a perennial spring ephemeral that occurs across a large portion of eastern North America. The species occurs in deciduous forests where it has a distinctive life cycle with separate reproductive and photosynthetic periods occurring in the spring. It has long been used as a food source in the Appalachian Mountains and has medical applications as well. Widely consumed throughout its range as a component of Appalachian culture, it increasingly faces harvest pressures due to burgeoning culinary popularity. Though regulations have been imposed in parts of its range and conservation efforts are underway in some places to restore denuded subpopulations, the species remains under threat due to high demand and the synergistic impact of harvest pressure, invasive competitors, and habitat loss. While the increased demand for Ramp has not been met with adequate regulation across its entire range, the species remains common and abundant in the core of its range. Therefore it is considered Least Concern. A. tricoccum subsp. burdickii is less common than A. tricoccum subsp. tricoccum and may require closer monitoring to ensure populations are stable. 

The former range of Ramps (Allium tricoccum) encompassed vast tracts of hardwood forest in eastern North America. Because of this, the species lends its name (in local Native American languages) to several places including Chicago (Edgar et al. 2012). Deforestation occurring over the course of the last two centuries has restricted and fragmented the range of the species considerably, though it remains broadly distributed.

The current northern extent of the range of Ramps is from Manitoba in the west to Nova Scotia in the east, including southern portions of Ontario, Quebec, and New Brunswick (VASCAN 2018). In the west, it occurs in isolated counties of North Dakota, South Dakota, Iowa, and Missouri (USDA, NRCS 2018). It is relatively common in the Appalachian region as far south as Tennessee and North Carolina and extending northward to New England and the southern portions of the Canadian Maritime Provinces. Two sympatric subspecies are widely recognized (Allium tricoccum subsp. tricoccum and A. tricoccum subsp. burdickii) (Flora of North America (FNA) Editorial Committee 2002).

Systematic surveys have primarily focused on the extreme northern and southern margins of the species’ range and few studies have examined the subpopulations occurring in the central and western segments of its distribution. At the southern margin of the species’ range, overcollection forced the closure of Great Smoky Mountains National Park following demographic studies suggesting harvest rates were unsustainable (Rock et al. 2004). Northern subpopulations may be equally denuded. Several subpopulations in western Massachusetts have been reportedly extirpated (Davis-Hollander 2011). In Quebec, 20% of known wild subpopulations have been extirpated (Nantel et al. 1996). Prior to the imposition of regulations on harvest, the majority of remnant subpopulations in the province were found to be below the minimum viable population of 300 to 1,030 plants.

In the central core of its range, including the “leek belt” of western New York (Cattaraugus, Allegany, and Steuben Counties) and northern Pennsylvania (Warren, McKean, Potter, and Tioga Counties), Ramp is said to be common (Edgar et al. 2012). Though no systematic surveys have been conducted in the area, subpopulations are not thought to be overharvested (Sen 2011).

Abundance also varies by subspecies A. tricoccum subsp. burdickii is rare throughout much of its distribution including core areas of the species’ range in which subsp. tricoccum is abundant (Edgar et al. 2012). The two subspecies can be distinguished by coloration of the bulb.  A. tricoccum subsp. burdickii has characteristically narrow leaves and lacks red to purple tint expressed at the edge of the bulb and prefers slightly drier environmental conditions (Edgar et al. 2012). Timing of anthesis is also distinguished between the two with A. tricoccum subsp. tricoccum flowering before A. tricoccum subsp. burdickii.

Harvest rates for the species appear unsustainable through much of its range, though data is lacking in the core. In the absence of data on the central core of the species range, inferences on harvest pressure must be made. Harvest pressure in New York is quite high and is driven by markets outside the local area. Given the increasing popularity of Ramps on culinary markets and existing high demands, population declines found at the margins of the species' range (which appear close to meeting criteria for threatened status) are likely to occur throughout the species' range in the near future.

Ramps occur in cool, shaded deciduous forests with acidic soils high in organic matter at elevations between 0 and 1800 metres (Davis and Greenfield 2002, Flora of North America (FNA) Editorial Committee 2002). It co-occurs with several deciduous hardwood species including sugar maple, beech, and hemlock (Edgar et al. 2012). The species is a perennial spring ephemeral which sprouts in early spring (late March through early April) prior to canopy closure which restricts available light (Bernatchez and Lapointe 2012). The photosynthetic period of the plant is very short as leaves die back in late May as canopy closure occurs (Davis and Greenfield 2002). Growth rate during this period is closely related to temperature with declines observed at temperatures above 14°C or below 8°C (Bernatchez and Lapointe 2012).

Leaf litter from early senescence of subaerial plant parts seems to have some impact on the soil microbiome in areas where the plant is present (Burke and Chan 2010). Ramps modify local soils through release of thionosulfinates which are toxic to earthworms and other insects and may be important check on the spread of invasive earthworm species (Hale et al. 2006). Additional soil chemistry modifications occur due to the plant’s early uptake and storage of nitrates followed by their subsequent release later in the season (Rothstein 2000). This contributes to a small portion of the “vernal dam” effect (the remainder being stored by bacteria). Though the impact of Ramps is relatively minor, their presence in an ecosystem may modify nutrient cycling of broader ecosystems.

Anthesis follows leaf senescence, during which an erect umbel, bearing self-compatible flowers is produced (Gleason and Cronquist 1991, Nault and Gagnon 1993). Ramp seeds remain dormant in soil for at least one year prior to germination requiring a warm, moist period to break root dormancy and a subsequent cold period for shoots to germinate (Davis and Greenfield 2002). Seed dormancy may extend to two or three years if environmental conditions are unfavorable for growth (Nault and Gagnon 1993). Development of soil seed banks may cushion against demographic shifts caused by unfavorable environmental conditions. Though germination rates are relatively high, sexual reproduction is rare due to a number of factors. Scape mortality is very high prior to seed development meaning that few plants that flower actually produce viable seed. Seedling survival rates are also very low with 30% of seedlings surviving their first year and only 4% remaining after three years (Nault and Gagnon 1993). Once individuals reach maturity, annual mortality drops to 10%. Individuals first flower seven to ten years after seed set (Nault and Gagnon 1993).

Ramps may also reproduce vegetatively from existing bulbs and may form extensive colonies with complete ground coverage (Edgar et al. 2012). Division is strongly linked to flowering suggesting that timing of seed set and asexual reproduction are likely to be very similar (Nault and Gagnon 1993). Some distinction in reproductive strategy is evident between subspecies of the plant with asexual reproduction dominating more in subsp. tricoccum than in subsp. burdickii (Edgar et al. 2012). Given the demographic data presented above and an estimated annual fertility rate of 0.5 for all age classes above eight years of age, generation time is estimated to be 18 years.

The largest threat to the species is harvest pressure. Widespread collection has depressed total population and resulted in subpopulation extirpations in several areas of the species’ range. Harvest pressures are linked to economic conditions and poverty is thought to drive overcollection in many areas (United Plant Savers 2016).

Estimates of sustainable whole plant harvest rates vary considerably but generally center on removal of five to ten percent of a given stand on an annual basis. Nantel et al (1996) determined that an annual harvest rate of 8% was sustainable in Quebec given the stochastic nature of natural population growth rates. Said variation has considerable impact on sustainable rates from year to year with Nault and Gagnon (1993) proposing 5-15% annual harvest levels depending on environmental conditions. At the southern margin of the species’ range, sustainable harvest rates estimated from Great Smoky Mountains National Park are somewhat more pessimistic. Population recovery was modelled suggesting 5% harvests every 2.5 years were sustainable though stochastic variability produced recovery times from a 5% harvest ranging from one to 89 years (Rock et al. 2004). The authors proposed a sustainable harvest rate of 10% of a given subpopulation every ten years. Unfortunately, the sustainability of harvest rates have not been analyzed for the central and western portions of the species’ range. The above figures may not apply to the totality of the population due to regional variation in climate and other factors.

In addition to the rate of harvest, the strategy chosen by harvesters may also have an impact on sustainability. Nantel et al (1996) outline two strategies observed from seized bulb measurements. “Choosy” harvesters preferentially collect larger bulbs leaving smaller individuals relatively intact while “busy” harvesters collect more individuals with less size specificity. The former strategy was found to be more detrimental to population as it selectively removed individuals most likely to reproduce through either sexual or asexual means.

Harvest may have synergistic impacts and compound the deleterious impacts of other threats. Disturbance of soil caused by harvest has been noted to increase the rate of spread of invasive garlic mustard (Alliara petiolata) which may outcompete Ramps (Davis-Hollander 2011). In addition to garlic mustard, honeysuckle (Lonicera maackii) may outcompete and shade Ramp stands when exposed areas within clusters are created by harvesters (Edgar et al. 2012).

In some areas habitat loss may impact the species due to urban development and deforestation (Edgar et al. 2012). In addition to habitat loss, habitat fragmentation caused by development has increased the impact of harvest pressure by providing access to interior forest environments (Nantel et al. 1996). Seed predation by deer mice (Peromyscus maniculatus) has been observed, though caching behavior appears to be the primary mechanism of seed dispersal (Nault and Gagnon 1993). It is unclear how climate change may impact the species but several factors suggest it may be vulnerable to changes in seasonal temperature variation. Spring growth is limited to a narrow temperature range and the species occurs in high altitude environments at its southernmost extent (Bernatchez and Lapointe 2012). Collectively, these factors suggest that even minor temperature changes could result in large biogeographic shifts.

Ramps have historically been an important source of vitamin C for both Native Americans and early European colonists throughout its range as the species is one of the earliest edible plants to sprout in the spring (Rivers et al. 2014). Cultural associations with Ramps are a component of Appalachian identity (Rivers et al. 2014). This cultural association with the people of Appalachia and stereotypes regarding poverty in the region led to persecution of the species outside the Appalachian region during the late 19^th century (Edgar et al. 2012).

Ramp festivals are a common practice within the Appalachians with the celebrations focusing on foods containing Ramps and communal harvest of the plant. Often these festivals serve as fundraisers in addition to community gatherings (Chamberlain 2003). Consumption of Ramps at such festivals has been notably increasing with the growing popularity of culinary usages of Ramps outside the Appalachian region. Ramp festivals account for 2,000-3,200 pounds of annual Ramp consumption with most of this harvest taking place on National Forest administered land (Chamberlain 2003, Chamberlain 2004, Davis-Hollander 2011).

Culinary usage of Ramps has increased since 1990 with the trend accelerating since 2000 (Davis-Hollander 2011). Global harvest levels have been estimated at two million pounds per year (Davis-Hollander 2011). A single producer in New York harvests 18,000 – 20,000 pounds for markets in New York City annually (Sen 2011).

In addition to use as a food resource, Ramps have been consumed for medicinal purposes. Native American culinary and medicinal usage of the plant was and is practiced by the Cherokee, Chippewa, Iroquois, Ojibwa, and Potawatomi (Moerman 2018). Common uses include as a cold remedy, spring tonic, and antihelmintic. Folk usage of the plant includes use as a blood cleanser and as a cold remedy (Cavender 2006). The entire plant is eaten for this purpose throughout the Appalachian region. Recent research has demonstrated that selenocompounds contained in Ramps, as well as other members of the genus Allium, have potential pharmaceutical application for the treatment of cancer (Whanger 2002).

Market prices for Ramp vary considerably based on location and the abundance of local populations. Prices in New York vary from $12 to $25 per pound (Edgar et al. 2012). Estimates of total collection levels are difficult to establish due to the decentralized nature of Ramp markets. With much of the collection pressure driven by local communities and consumption by collectors themselves, accurate figures regarding total harvest are not available.

Harvest of Allium tricoccum subsp. burdickii is restricted in much of its range, including in the state of New York (Edgar et al. 2012). A. tricoccum subsp. burdickii is classified as Endangered in New York and as Commercially Exploited/Vulnerable in Tennessee. A. tricoccum subsp. tricoccum is classified as Special Concern in Maine, Rhode Island, and Tennessee (USDA, NRCS 2018). Conservation status of the plant varies widely across its distribution with NatureServe (2018) classifying the species as Critically Imperiled (S1) in Manitoba, Nova Scotia, Tennessee, and Alabama while subpopulations are considered Secure (S5) in New York and Virginia and Apparently Secure (S4) in large portions of its native range.

In 2004, the Great Smoky Mountains National Park began enforcing a prohibition on Ramp harvest within the park (Sen 2011). This led to a legal dispute with the Eastern Band of Cherokee Indians who have historically harvested Ramps in the area (Lewis 2012). Following this dispute, the Eastern Band Cherokee were exempted from the harvest ban.

Quebec designated the species Vulnerable in 1995 and has prohibited the sale of wild leeks. Harvest limits of 200 g per person have also been put in place. In addition, harvest of the species has been banned since 1980 in Montreal’s Gatineau Park where a minimum fine of $500 has been instituted for illegal harvest (Edgar et al. 2012). Despite these regulations, illegal harvest continues in Quebec, with most plants being sold in neighboring Ontario where protections on the plant are not as strong (LeBlanc 2014).

Sustainable harvest of wild subpopulations is one component of conservation actions, though proposed methods vary considerably. Some harvesters report replanting a segment of rhizome from each collected plant, though the measure appears to not be effective at regenerating harvested plants (Chamberlain 2004). Harvest methods employed by the Cherokee may be a model for sustainable harvest. Their traditional harvest method which continues today harvests only leaves from 10% of a given subpopulation allowing for regrowth between visits to the same patch (Lewis 2012). The sustainability of leaf harvest is disputed, but is agreed to be much greater than whole plant harvest. Davis-Hollander (2011) has proposed harvest of only leaves from 20% of any given stand on a five year rotation while noting that overharvest may adversely impact subpopulations. Given that seedling recruitment is greatest at the edge of stands (Nault and Gagnon 1993), encouraging harvesters to collect only those plants at the margins of existing stands may also have favorable impacts on population viability. Some movement toward leaf harvest has occurred within the Ramp festival community. The Hudson Ramp Fest has become leaf-only to promote conservation measures associated with Ramp harvest (United Plant Savers 2016).

Increased regulation through permitting has been proposed to prevent excessive harvest pressure. To this end, North Carolina has instituted a permitting system charging $0.50 per pound of collected Ramp for up to 500 pounds of commercial collection (Edgar et al. 2012). Collection of Ramp for personal use is unregulated up to a total of five pounds. Cultivation is another possible method of supplying markets with sustainable Ramps. Given the appropriate conditions, the plant can be cultivated easily (Davis and Greenfield 2002). Given proper conditions, the species can be cultivated through seed or vegetative propagation. Some evidence suggests that given high soil moisture and proper temperature conditions, the species could be cultivated in open agricultural fields (Vasseur and Gagnon 1994). Some reluctance exists with regard to cultivated Ramp, however, with some of the culinary appeal being driven by trends emphasizing local and foraged foods (Sen 2011). Labeling has also been proposed including issuance of sustainable harvest labeling for Non-Timber Forest Products (NTFP) (Edgar et al. 2012).

Reintroduction of Ramp has occurred in Quebec since 1999 through the SEM’AIL project. Between 2000 and 2004 one million seeds were distributed to private owners of properties including maple forests and 440,000 seized bulbs have been replanted (SEM’AIL 2018). These reintroduction efforts have successfully established subpopulations at 80% of selected sites.

Conservation measures impacting Ramp may have added benefits to medicinal species that co-occur and are commonly harvested in conjunction with Ramp including mayapple (Podophyllum peltatum), trillium (Trillum spp.), bloodroot (Sanguinaria canadensis), and black cohosh (Actea racemosa) (Edgar et al. 2012).