Land Retirement Demonstration Project

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The Suitability Trial was developed to evaluate the performance (i.e., establishment and growth) of various native species under field conditions at the Tranquillity Demonstration Site. Forty-three species were initially considered for inclusion in the trial. These species represented species that had previously been used in restoration activities in California. The species were ranked based on 18 criteria (see, Uptain et al. 2004, p. 136). Six species (five perennial grasses and one sub-woody perennial), were selected for inclusion in the trial.

Each species was planted (imprinted) in a single, approximately 0.13 ha (0.33 ac) plot (12' x 1200'). This approach was adopted because of difficulties associated with seeding small plots with an imprinter. Although this experimental design promoted a more equitable seeding of the plots, this approach limited the analysis options as there were no true replicates (see Hurlbert 1984 for a discussion of pseudoreplication). Hence, rather than being treated as a rigorous experiment, this trial should be interpreted more as a structured step in identifying suitable species for inclusion in restoration efforts.

Imprinting was undertaken on 15 March, 2002. The plots were sprinkler irrigated twice during the course of the experiment (March and April, 2002). Vegetation sampling was conducted during June 16-18, 2002). Plots were divided into 40 equal-length (ca. 9.2 m; 30 ft.) segments; vegetation data were collected from one randomly located quadrat (35 x 70 cm) within each segment.


Hurlbert, S. H. 1984. Pseudoreplication and the design of ecological field experiments. Ecol. Monogr. 54: 187-211.

Uptain, C. E., N. P. Ritter, S. L. Lee, J. Brummer, S. A. Laymon, K. R. Garcia, A. J. Howard, G. Basso, K. E. Kreitinger, S. E. Phillips, S. R. Messer, D. P. Newman, E. M. Magill, L. L. Williams, P. A. Kelly and D. F. Williams. 2004. Land Retirement Demonstration Project Year Four. 2002 Annual Report. Endangered Species Recovery Program, Fresno, CA. 273 pp.

Page created: March 1, 2005; Last updated: Dec. 20, 2005

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The Land Retirement Program is a Department of the Interior program
composed of representatives from the USBR, FWS, and BLM.