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Individual study: A hairy vetch Vicia villosa cover crop increases establishment success of transplanted sweetgrass Anthoxanthum nitens at Kanatsiohareke and LaFayette Experiment Station, New York, USA

Published source details

Shebitz D.J. & Kimmerer R.W. (2005) Reestablishing roots of a Mohawk community and a culturally significant plant: sweetgrass. Restoration Ecology, 13, 257-264

Summary

Sweetgrass Anthoxanthum nitens is an example of a culturally significant plant used by indigenous people (for example, in traditional medicine and basket making) that is reportedly declining in traditional gathering sites in northeastern USA. This decline is in part is attributed to competition with non-native plants. This project evaluated methods to reintroduce sweetgrass to Kanatsiohareke (near New York) so that traditions associated with the species will endure through basket-making and social sweetgrass harvesting, and enable others to establish sweetgrass gardens near their homes.

This project has two main objectives: to assess the restoration potential of sweetgrass; and to evaluate the effects of four reestablishment methods on the success of sweetgrass establishment.

Study sites: The restoration potential of sweetgrass Anthoxanthum nitens was evaluated through a field experiment conducted on Kanatsiohareke, a Mohawk indian farm, and at the LaFayette Experiment Station near Syracuse, New York. The particular location at Kanatsiohareke was chosen as it was indicated by members of the Mohawk community as an area historically having sweetgrass and was similar in structure and composition to other sweetgrass-harvesting areas.

The existing vegetation at both LaFayette and Kanatsiohareke was old-field vegetation dominated by non-native grasses. Soils at Kanatsiohareke had a lower percentage of sand and higher percentage of silt and clay than those at site at the LaFayette Experiment Station.

The closest area to Kanatsiohareke where sweetgrass is harvested in large quantities is near the Akwesasne Mohawk Territory (on the border of northern New York and Canada), approximately 325 km from Kanatsiohareke. Although sweetgrass occurs naturally at Akwesasne and the surrounding areas, it is becoming more difficult to locate and gatherers believe that it is declining.

Sweetgrass cultivation: The sweetgrass used in the experiment was grown in a nursery bed at the LaFayette Experiment Station. The original source comprised 100 tillers from a nursery in northern New York State, purchased in 1997. Three years after planting these sweetgrass tillers, had multiplied and supplied 1,960 tillers that were used in the experiment.

Sweetgrass reestablishment The effects of competition reduction and two cover crops on sweetgrass reestablishment success were examined by comparing establishment of sweetgrass planted under four treatments:

1) sweetgrass alone

2) with existing, old-field vegetation

3) with a cover crop of Hairy vetch Vicia villosa

4) with a cover crop of Italian (annual) ryegrass Lolium multiflorum

The experiment consisted of five replicates of the four treatments at both LaFayette and Kanatsiohareke.

Sweetgrass survival & growth: Most sweetgrass transplants at Kanatsiohareke (87%) and LaFayette (70%) survived through the first growing season, and persisted in all plots a year following planting. Sweetgrass survival was greatest in the hairy vetch plots and the manually weeded plots at both sites.

Sweetgrass increased by as much as four times the original amount in the first growing season and by as much as 20 times in the second year. Tiller density continued to increase even after weeding ceased in the plots in which weed competition had been manually controlled.

Sweetgrass biomass, height, reproduction rate and survival were greatest in plots that were weeded to eliminate competition and in plots with hairy vetch as a cover crop.

A year after sweetgrass was planted, the effect of hairy vetch was evident through the low abundance of competitive weeds, although the vetch itself was no longer present. The cover crop of italian ryegrass (which persisted into the second growing season) resulted in reduced sweetgrass growth and reproduction.

Conclusions: The results of these experiments indicate that there is great restoration potential for sweetgrass as it is easily transplanted and reproduces vigorously, mostly though a rapid increase in tillers. Of the plots in this study, those with a hairy vetch cover crop proved most effective for successful sweetgrass establishment and growth. Planting the sweetgrass with hairy vetch also generated grass properties desired by basketmakers, such as abundance and long leaf blades. This technique also allowed for a relatively non–labor intensive method of cultivation.


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