New Jersey rush (Juncus caesariensis) COSEWIC assessment and status report: chapter 11

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Technical summary

Juncus caesariensis

New Jersey Rush – jonc du New Jersey

Extent and Area Information

Population Information

List populations with number of mature individuals in each:

Data are available for the year 2002 for the following 24 of 25 populations:

• Gracieville (“bog 4”): 200-500
• Gracieville (“bog 5”): >500
• Gracieville (“bog 3”): 50-100
• Gracieville (“bogs 1 & 2”): 110-250
• Gracieville: 200-500
• Point Michaud: <10
• Point Michaud (“German bog”): 100-200*
• Point Michaud (“elbow bog”): 50-100
• Grand River (“bog 8”): 200-500
• Grand River (“bog “9b”): 200-300
• Grand River West: number of mature individuals unknown
• Grand River East 1: number of mature individuals unknown
• Grand River East 2: number of mature individuals unknown
• Grand River (Indian Point): <10
• L’Archevêque/St.Esprit: 10-50
• St. Esprit: 40+
• Lower St. Esprit: 30+
• Stirling: 100-200
• Framboise/Fourchu: >500
• Mulcuish Lake: 500-1000
• Mulcuish Lake (gravel pit): number of mature individuals unknown
• Loch Lomond (Graces Road 1): 500+
• Loch Lomond (Graces Road 2: 50-100
• South Arm Breeches Lake: number of mature individuals unknown

Threats (actual or imminent threats to populations or habitats)

• wetland alteration due to road, cottage and home construction;
• logging in adjacent habitat;
• all-terrain vehicle activity

Rescue Effect (immigration from an outside source)

Quantitative Analysis

Not Applicable

Other Status

• COSEWIC: Special Concern (1992)
• Nova Scotia Endangered Species Act: Vulnerable

Status and Reasons for Designation

Status: Special Concern

Alpha-numeric code: [Met criteria for Threatened, D2, but designated as Special Concern because there are about 25 extant occurrences and likely more to be found; the species is not likely to become highly endangered since there are limited risks and the species shows some adaptability to habitat disturbance.

Reasons for Designation: The species is a globally rare plant found along the periphery of 25 bogs and fens in a geographically restricted area of southeastern Cape Breton Island, Nova Scotia. The Canadian population is estimated at 5000 -10,000 plants that comprise a large proportion of the global population. The Canadian plants are widely disjunct from sites along the U.S. Atlantic seaboard where the species is also quite rare. It is sensitive to activities that alter the hydrological regime of its habitat such as logging, road construction and in-filling.

Applicability of Criteria

Criterion A (Declining Total Population): Not Applicable: No declines documented
Criterion B (Small Distribution, and Decline or Fluctuation): Not Applicable: No continuing decline documented; populations > 10 and not fragmented
Criterion C (Small Total Population Size and Decline): Not Applicable: No continuing decline
Criterion D (Very Small Population or Restricted Distribution): Threatened under D2 based on the small area of occupancy
Criterion E (Quantitative Analysis): Not Applicable