• Status
• Family
• Description
• Range and Population Level
• Habitat
• Threats
• Conservation
• What You Can Do
• References

STATUS: Threatened (Federal Register, July 18, 1991)

FAMILY: Cyperaceae

DESCRIPTION: Knieskern's beaked-rush is a plant of the sedge family endemic to the Pinelands region of New Jersey. The genus name Rhynchospora is from the Greek rhynchos, meaning beak and spora, meaning seed, which refers to the beaked seed or fruit that is characteristic of the genus. This grass-like plant was generally considered to be an annual species (i.e., living for only one season); however, it is currently suspected to be a short-lived perennial in locations where habitat conditions are stable enough to allow uninterrupted growth year after year. Knieskern's beaked-rush grows from 1.5 to 60 centimeters high (0.6 to 24 inches), has slender culms (stems) branching from the base, and short, narrowly linear leaves. Small spiklets (flower clusters) are numerous and occur at distant intervals along the entire length of the culm. The achene (fruit) is obovate, narrow at the base, 1.1 to 1.3 millimeters long (0.04 to 0.05 inches), and equal in length to the six downwardly-barbed, or rarely, upwardly-barbed attached bristles. A tubercle (beak), which is the persistent base of the two-cleft style (slender stalk containing the pollen tube) on top of the achene, is about one-half the length of the achene (U.S. Fish and Wildlife Service, 1993).

Knieskern's beaked-rush is an obligate hydrophyte (wetland plant) that occurs in groundwater- influenced, constantly fluctuating, successional habitats. An early successional species and colonizer, this species is intolerant of competition, especially from woody species. It is found on naturally occurring early successional habitats and disturbed habitats such as burns, gravel and clay pits, road cuts, mowed roadsides, utility and railroad rights-of-way, cleared home sites, eroded areas, cleared edges of Atlantic white-cedar swamps, wheel ruts, and muddy swales (Gordon, 1993; U.S. Fish and Wildlife Service, 1993; Radis, 1995). Periodic disturbance, either natural or human-induced, which maintains a damp-to-wet site in an early ecological successional stage may be necessary for the successful colonization, establishment, recruitment, and maintenance of this species. Although not all plants produce culms each year, flowering and seed production have been observed in very young plants. Fruiting typically occurs from July to September. Seed dispersal mechanisms are not documented; however, bristles located on the achenes could assist in animal dispersal (U.S. Fish and Wildlife Service, 1993).

RANGE AND POPULATION LEVEL: Knieskern's beaked-rush has always been considered rare (Stone, 1911). Currently, the species is only known to occur in New Jersey (Atlantic, Burlington, Camden, Monmouth, and Ocean Counties). Historically, two documented occurrences were found in Sussex County, Delaware. The Delaware Natural Heritage Program has been conducting yearly surveys for Knieskern's beaked-rush over the past 10 years without finding a single new occurrence (McAvoy, pers. comm., 1997). The total number of documented occurrences in New Jersey is 52, which includes 14 historical and 38 extant populations. Six of the extant populations occur on sites that are considered to be naturally maintained in an early successional vegetative stage and therefore, should not require active management. The remaining 32 known extant populations occur on early successional sites created as a result of sand, clay, and gravel mining; borrow pit excavation; cranberry bog construction; and road, powerline, and ditch construction through wetland areas. Of the 32 extant populations occurring on human-disturbed sites, three are on federal property, four are on State property, and 25 are on private property or rights-of-way (U.S. Fish and Wildlife Service, 1993).

HABITAT: The habitat originally thought to be required for the species is associated with bog- iron deposits (Stone, 1911), which generally occur adjacent to slow-moving streams in the New Jersey Pinelands region. Boyd (1991) describes the formation of bog-iron deposits as a product of the chemical action of slow-moving acid stream waters with the iron laden soils of stream beds. Soluble iron, which is oxidized by the aerated water and oxidizing bacteria, precipitates as red flocculent and sludge. This precipitate settles out of the moving water and becomes deposited in stream beds and adjacent wetland bogs, mixing with sand, mud, and decayed vegetation while continuing to harden into thick, rocky "ironstone" ore beds. These bog-iron deposits are subject to the erosional forces of the stream system that combine with the durability of the bog-iron, allowing the habitat to remain essentially unchanged in an early ecological successional stage. Bog-iron sites are considered to be a naturally maintained and long-lasting habitat for the species.

In the past, fire may have played an important role in creating and maintaining suitable habitat for Knieskern's beaked-rush. Occurrence records for Knieskern's beaked-rush indicate that this plant is found in wet open areas within fire-dependent open pitch-pine forests. Fire suppression during the past century has changed the floral composition of the New Jersey Pinelands region and may have eliminated, or altered, a component of the ecosystem that naturally maintained habitat for this species (U.S. Fish and Wildlife Service, 1993).

Recent records on Knieskern's beaked-rush document that this species occurs in early successional wet habitats created by human disturbances. These sites include: the edges of abandoned clay, sand, and gravel pits; borrow pits that are functioning as vernal ponds; ditches; unimproved roads; and, railroad and powerline rights-of-way. Human-disturbed sites exhibit some of the same characteristics as bog-iron sites, including a high water table, temporary inundation, and open, early-successional habitat with relatively bare substrate. In general, most of these sites require periodic human-induced disturbance to maintain their early-successional character (U.S. Fish and Wildlife Service, 1993). Plant species associated with Knieskern's beaked-rush include warty panic-grass (Panicum verrucosum), poverty-grass (Aristida longispica), and spatulate-leaved sundew (Drosera intermedia) (Gordon, 1993).

THREATS: Originally, the primary threat to the species was the loss of wetlands to urban and agricultural development. However, current State and federal wetland protection laws have reduced the loss of wetlands over time. Presently, vegetative succession is a major factor threatening Knieskern's beaked-rush; 19 of the 38 extant populations are currently undergoing vegetative succession that could eliminate these populations. Without periodic intervention to reverse successional trends, these 19 sites will most likely become unsuitable for the species in the future. Human-induced threats to the species include alteration to wetland hydrology, off-road vehicles, trash dumping, and possibly roadside grading (U.S. Fish and Wildlife Service, 1993). Gordon (1993) found that fire can be both beneficial and detrimental to the species depending on the timing, duration, and intensity of the burn.

CONSERVATION:

Goals: The primary recovery goal for Knieskern's beaked-rush is the permanent habitat protection of existing sites. Habitats can be protected by developing management strategies for both public and privately owned Knieskern's beaked-rush sites and by securing commitments from land management agencies for long-term monitoring of the species. Further recovery objectives are to determine the capacity of the species to colonize new sites and establish populations. Continuing research on the species' life history, population viability, and specific habitat requirements is also essential to the species' recovery (U.S. Fish and Wildlife Service, 1993).

Success Stories: The New Jersey Natural Heritage Program surveyed historical sites and new sites for Knieskern's beaked-rush in 1984 and 1985 using a soil/habitat predictive method. This method consisted of searching sparsely vegetated, open seepage areas of sandy loam or clay on soil types know to support other occurrences of the species. Several additional populations were discovered during these surveys.

In 1991, W.E. Brumback of the New England Wild Flower Society, Garden in the Woods, began germination tests on seeds collected by D.B. Snyder of the New Jersey Natural Heritage Program. Seeds that were placed in a seed-bank in December 1991 germinated after being removed from the bank and sowed in February 1995, demonstrating that Knieskern's beaked-rush can be seed- banked successfully. Brumback also found that Knieskern's beaked-rush has a perennial nature when plants bloomed in two consecutive growing seasons during 1992-93 (Brumback, pers. comm., 1997).

The Service has also established agreements with the U.S. Department of the Navy, Federal Aviation Administration, and the New Jersey Division of Fish, Game and Wildlife to protect known occurrences of Knieskern's beaked-rush.

WHAT YOU CAN DO: Private landowners with Knieskern's beaked-rush on their property can help protect the species by preventing people from picking or digging the plant and by contacting the U.S. Fish and Wildlife Service to develop a protection and management strategy for the property.

If you find plants that appear to be Knieskern's beaked-rush, carefully note their location and, if possible, photograph the plant. Please do not remove the plant! Notify the U.S. Fish and Wildlife Service and your State's Natural Heritage Program.

For more information please contact:

Natural Heritage Program
Division of Parks and Forestry
CN 404
Trenton, New Jersey 08625
Telephone: 609/984-0097

U.S. Fish and Wildlife Service
New Jersey Field Office
927 North Main Street, Building D
Pleasantville, New Jersey 08232
Telephone: 609/646-9310