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COSEWIC Assessment and Status Report on the Baikal Sedge in Canada

Biology

General

The biology of Carex sabulosa has not been studied. It is evident, however, that this species can withstand high, desiccating winds and tolerates shifting sands, which can bury most of the clones.


Reproduction

Reproduction of Carex sabulosa is by seed and rhizomes. It is apparent, from the widely disjunctive populations in northwestern North America, that dispersal of the seeds, over at least moderate distances, is possible. On both the active (Carcross and Takhini River) and semi-stabilized (Kaskawulsh/Dezadeash Rivers) sand dunes, the rhizomatous nature of the plants is readily evident (Figure 9).


Survival

Sand deposits of depths greater than 1 m, over short periods of time, appear to restrict or prevent the growth of Carex sabulosa ramets.


Physiology

No information is available.


Genetics

No information is available.


Movements/Dispersal

Carex sabulosa reproduces successfully from rhizomes in local populations. The population at the confluence of the Kaskawulsh/Dezadeash rivers occupies, due mainly to its rhizomatous habit, almost all the stabilized sand dune habitat in the area. This is also readily evident on the active dunes at Carcross. Parts of the latter dunes, and about 90% of the dunes along Klondike Highway at Carcross, are so unstable that vascular plants are unable to establish.


Figure 10: Exposed Root System of Carex sabulosa at the Klondike Highway Dunes, Near Carcross

Figure 10: Exposed root system of Carex sabulosa at the Klondike Highwaydunes, near Carcross.

The root system (a rusty-brown colour when seen in the field) is readily evident at this eroded sand bank. All the fibrous roots in this photo belong to Carex sabulosa clones. Below-ground biomass at this site is probably 10 to 20 times greater than above-ground biomass (Photo by S.J. Smith, Douglas Ecological Consultants Ltd.).

Dispersal of C. sabulosa by seeds, over at least moderate distances of 40 to 100 km is demonstrated by the Yukon sites (Figure 4). It is quite evident from geomorphological features that sand dunes were a common feature on the landscape during the Pleistocene. It is likely that Carex sabulosa would have been required to move at intervals to temporarily ice-free sites during the Pleistocene since most of the region was covered by ice at various times. Studies indicate that all the valleys in the region were covered to a depth of 1825 to 2194 m elevation (Kindle 1952, Day 1962, Krinsley 1965, Muller 1967). Wheeler (1963) noted glacial erratics at an even higher elevation than 2194 m on Outpost Mountain just south of Kluane Lake.

Movement of the species between the southern Yukon and the nearest North American site, 900 km away in central Alaska, was probably by occupation of smaller refugia or temporarily ice-free areas during glaciation. Transportation by birds is also a possibility. In Alaska, C. sabulosa occurs in the Nogahabara Sand Dunes within the Koyukuk National Wildlife Refuge (Alaska Natural Heritage Program, 2002). This refuge is within the Alaska/Yukon Refugium, an extensive refugium that was ice-free during the Pleistocene. Rescue of Canadian populations by propagules from Alaskan plants is unlikely.


Nutrition and Interspecific Interactions

No information is available.


Behaviour/Adaptability

No information is available.