- Common name (english): False hop sedge
- Common name (french): Carex faux-lupulina
- Latin name : Carex lupuliformis
False hop sedge is a rare plant for which a great number of populations have now disappeared and the remaining is still experiencing serious threats. Due to its precarious situation, a recovery plan has been implemented in 2006 by a team from the Institut de Recherche en Biologie Végétale.
What is false hop sedge?
False hop sedge is a grass-like herbaceous perennial plant from the Cyperaceae family growing in clumps. It can reach heights of 50 to 130 cm and each individual possesses female as well as male flowers. In Canada, it generally blooms from June to August and produces fruits from July to October. False hop sedge’s name comes from the fact that it looks just like hop sedge (Carex lupulina) which is an abundant species in Canada that can be found in roughly the same habitats. The only morphological difference which accurately allows distinction between the two species is that the achene (fruit) of false hop sedge possesses thick angles with knobby projections.
Where does false hop sedge live?
False hop sedge is found only in Eastern North America, from Texas and Florida in the south, up to the southern limits of Ontario and Québec. With only 10 known populations that are still standing in Canada, false hop sedge is one of the rarest sedge in the country.
Of the 11 Quebec populations once inventoried, only three are still standing today and they are all located within a segment of approximately 10 km on the banks of the Richelieu River. Formerly, false hop sedge could also be found in the vicinities of the Lake of Two Mountains and on the banks of the Ottawa River. Each of the three Quebec populations contains a very limited number of individuals (between two and 20). In all of Quebec, a total of less than thirty plants were found in 2010!
In Ontario, seven out of the nine known populations of false hop sedge are still extant. They are all located within the counties of Elgin and Middlesex. About 200 plants were reported in 2009 within Ontario populations.
Within its distribution area, false hop sedge is always associated with various wetlands that are rather open and subject to seasonal flooding. By comparison, the look-alike hop sedge can grow in shadier zones of the same habitats.
In Quebec, false hop sedge is exclusively found on riparian floodplains and located generally at the edge of silver maple stands or beneath an opening of their canopy. In Ontario, it mainly grows on small temporary pond shores that are isolated within red maple, silver maple or ash marshes.
What is the status of false hop sedge?
False hop sedge has been designated as a Threatened species in Quebec since 1998 and is therefore protected by the Act respecting threatened or vulnerable species from the Ministère du développement durable, de l’environnement et des parcs. In Ontario, it has been designated as an Endangered species since 2000 and is thus protected under the Endangered Species Act of Ontario Ministry of Natural Resources, following recommendation of the Committee on the Status of Species at Risk in Ontario.
At the federal level, false hop sedge has been designated as an Endangered species in 2000 by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). It was registered on Schedule 1 of the list of Wildlife Species at Risk in 2003 and is thus protected, on federal land, by the Species at Risk Act.
Why is false hop sedge at risk in Canada?
There are only very few populations of false hop sedge, each containing an extremely limited number of individuals. Added to which, its habitat is prone to important episodic disturbances such as flooding and drought. Furthermore, false hop sedge is sensitive to canopy closure as well as competition, especially by invasive exotic species such as reed canary grass (Phalaris arundinacea) and common buckthorn (Rhamnus cathartica). Infestation by an exotic aphid seems to be another rather threatening problem to the survival of this species. Finally, the destruction of its habitat in favour of urban, industrial, residential and agricultural development also represents an ongoing threat.
Which actions have been taken to save false hop sedge?
Given the critical situation that faces false hop sedge, various measures have been taken in order to stop the species decline and avoid its extinction. A conservation plan has been generated in 2006 by the Ministère du Développement Durable, de l’Environnement et des Parcs. With respect to the conservation plan, a recovery plan has been developed by a team from the Institut de recherche en biologie végétale in collaboration with the Montreal Botanical Garden, Montreal Biodome, Environment Canada, the Ministère du Développement Durable, de l’Environnement et des Parcs, the Ministère des Ressources Naturelles et de la Faune, WWF-Canada, and Laboratoires Klorane.
The program is mainly carried out in the province of Quebec and involves six objectives: 1) the search for new populations; 2) the monitoring of extant populations; 3) the reintroduction of individuals and the increase of populations size; 4) characterization of the species ecology and biology; 5) ex-situ conservation; and 6) raising awareness about the species situation.
1) Search for new populations
Since 2006, several kilometres have been explored along the shores of the Lake of Two Mountains, as well as on the banks of the Ottawa River, the Richelieu River and the South River, which is a tributary of the Richelieu River. Unfortunately, no new false hop sedge population has been discovered. However, we identified about ten sites which would be suitable for introducing or reintroducing the species.
2) Monitoring of existing populations
Each of the known natural plants has been permanently identified using a metal stalk as well as unique identification number. It is thus possible to detect trends within populations. Follow-ups are conducted once a year. For each individual, physical traits (height, number of stalks, etc.) as well as reproductive traits (status, number of male and female spikes, etc.) are registered. This information allows us to estimate population health status and trends.
3) Reintroduction and increase of population size
The low number of populations and individuals within them is the main threat for false hop sedge long term survival. In order to damper that threat, over 600 that had been produced in Montreal Biodome’s greenhouses were introduced on the shores of Richelieu River and in the Oka National Park between 2006 and 2010. By 2010, almost 30% of all transplants were still alive.
4) Ecology and biology
In order to perfect our knowledge on false hop sedge as well as on its suitable habitat, many abiotic variables such as light, water table fluctuations, and substrate nutrient concentrations, were collected over the years. Preliminary analyses suggest that soil conditions (nutrient content, organic matter content, etc.) do not affect the plants’ survival nor its growth. Additionally, we have conducted several seed germination and viability experiments. We have thus observed a very high germination and viability rate of false hope sedge seeds which therefore showed that this species is not limited by this aspect of reproduction.
5) Ex-situ conservation
In order to ensure the species survival, ex-situ (outside of the natural habitat) conservation activities complement the in-situ (within the natural habitat) conservation efforts already undertaken. These actions secure a supply of biological material useful for new plant production as well as provide research opportunities that allow us to perfect our knowledge of the species. The specimens that are preserved ex situ are also used for raising awareness towards false hop sedge conservation as well as broadcast information about rare plant issues.
Over a hundred false hop sedge live specimens are currently kept at the Montreal Botanical Garden where they are integrated with the existing outdoor collections, in particular within the Aquatic garden and the Boisé des frênes. Furthermore, several thousand seeds of the species are currently kept within two world seed banks: the Gene Bank at the Plant Gene Resources of Canada organization, as well as the Millenium Seed Bank at Kew Royal Botanical Gardens, in England.
Several activities aimed at raising population awareness towards false hop sedge conservation issues have been carried out since 2006. For instance, popularization posters are currently exposed at the Montreal Botanical Garden (PDF), as well as at Oka National Park (PDF). Additionally, interpretive articles have been published in various media (Quatre-Temps, Le Devoir, etc.) and several conferences were given on this topic.