New Jersey rush (Juncus caesariensis) COSEWIC assessment and status report: chapter 5

Habitat

Habitat requirements

In Canada, New Jersey Rush occurs sporadically along the edges of fens and bogs, in small peripheral bays or coves of these same habitats, and in small boggy openings in coniferous woods (Newell and Newell, 1992). Most of these areas display strong fen characteristics.

Figure 3. Canadian distribution of Juncus caesariensis

Figure 3.  Canadian distribution of Juncus caesariensis.

In the United States, this plant is known from acidic, sphagnous, wet spring or seep areas that have a reliable source of flowing water but not standing water.  Habitats include open to shaded stream banks, seepy pond margins, swales, pine barren savannas, and Chamaecyparis thyoides (Atlantic White Cedar) swamps. (NatureServe, 2003).

The habitat occurrences of this species throughout its range suggest that it is dependent on a certain, as yet undetermined, hydrological regime for its survival.

Strong and Sheridan (1991) reported finding healthy populations of Juncus caesariensis in recently cut power line corridors in Virginia. The regular mowing of this area appeared to be beneficial to New Jersey Rush by reducing woody second-growth vegetation and maintaining open habitat. Ware (pers. comm., 1991) reported a reduction in plant numbers at one location in Virginia. This was attributed to an invasion of Sweet Pepper Bush (Clethra alnifolia).

In Nova Scotia, the frequent association of this species with animal and lightly used all-terrain-vehicle trails on the edges of bogs and fens (Newell and Newell, 1992) suggests a possible dependence on some level of disturbance for the maintenance of open habitat. These disturbances would reduce competition from other species. Seasonal flooding of New Jersey Rush habitats would also prevent the establishment of many species including shrubs.

A list of common associated species for Canadian populations of New Jersey Rush is presented below (Newell and Newell, 1992):

Picea mariana (Black Spruce), Calamagrostis pickeringii (Pickering’s Reed bent-grass), Muhlenbergia uniflora (Fall Dropseed Muhly), Carex exilis (Coast Sedge), Carex michauxiana (Michaux Sedge), Smilacina trifolia (Three-leaved False Solomon’s Seal), Myrica gale (Sweet Gale), Alnus rugosa (Speckled Alder), Sarracenia purpurea (Pitcher Plant), Aronia sp. (Chokeberry), Rosa nitida (Swamp Rose), Ledum groenlandicum (Labrador Tea), Kalmia angustifolia (Sheep Laurel), K. polifolia (Bog Laurel), Chamaedaphne calyculata (Leatherleaf), Solidago uliginosa (Bog Goldenrod), Aster nemoralis (Bog Aster).

Other rush species that may be found with Juncus caesariensis are Juncus canadensis (Canada Rush) and Juncus brevicaudatus (Narrow-panicled Rush). Occasionally, Juncus stygius ssp. americanus (Moor Rush) is also found in the same habitat as New Jersey Rush. This species is ranked by the Atlantic Canada Conservation Data Centre (ACCDC) as an S1 species.

Additional rare plants encountered in the vicinity of Juncus caesariensis populations include Selaginella selaginoides (Low Spike-moss), Carex tenuiflora (Sparse-flowered Sedge), and the moss, Scorpidum scorpioides. Selaginella selaginoides is listed by the ACCDC as an S2 species and Carex tenuiflora is ranked S1.

In July of 1991, pH measurements and peat depths were recorded at five sites in the Point Michaud region (Newell and Newell, 1992). The pH at these locations ranged from 4.07 to 5.52. Peat depth ranged from 40 cm to greater than 2 m.

Trends

There is no historical information prior to 1992 on which to determine long-term trends in Canada.

Fieldwork in 2002 revealed some changes to the quality of New Jersey Rush habitat in Cape Breton over the past ten years.  There was an increase in all-terrain vehicle usage on some of the wetlands where New Jersey Rush occurs and in one case, a road had been constructed across a wetland (Site 3) in order to clear-cut the forest on the far side. The clear cut was taken to the very edge of the wetland.

Given the abundance of wetlands on southeastern Cape Breton Island, there is a strong possibility that still more populations (within the currently known range of this species) will be found with additional fieldwork.

Protection/ownership

Of the 25 sites known for this species, eight are located on crown land and the remaining seventeen are privately owned (Table 1). None of these sites fall within any protected areas.

New Jersey Rush is listed under the Nova Scotia Endangered Species Act as a vulnerable species. Under this act, species listed as vulnerable receive recognition as “species at risk” and require a management plan within three years of designation. However, destroying either the plants themselves or their habitat is not illegal.

Under the Nova Scotia Department of Environment and Labour’s Wetlands Directive, all alterations that may impact on a wetland require a permit. Wetlands over two ha in size require an environmental assessment before a permit is issued. Species at risk and wildlife habitat are two of the top considerations in issuing or not issuing a permit. However, for a variety of reasons, permits are sometimes issued inadvertently on wetlands that harbour species at risk. In other cases, development proceeds without any application for a permit being submitted.

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