Land Retirement Demonstration Project

The Native Release Trial

Overview

The Native Release trial was developed in order to examine the possibility of promoting germination of native seed in the seed bank by reducing competition from weeds. The trial was situated on a portion of the Tranquillity project site that possessed a good-sized population of the native annual forb, Malacothrix coulteri (snakes head). This area served as a seed collecting site for snakes head during the 2002-03 growing season. However, during the next two growing seasons the abundance of the invasive grass Bromus madritensis increased dramatically. Concomitantly, M. coulteri decreased in abundance to the point where there were insufficient individuals to allow harvesting.

It was hoped that by reducing Bromus madritensis through various weed-control methods Malacothrix coulteri might once again proliferate in the area. Four treatments were applied: 1) flaming {i.e., burning existing vegetation with an agricultural flamer}; 2) mowing; 3) spraying with Poast®, a grass-specific herbicide; and, 4) spraying with Roundup®, a broad-spectrum herbicide.

The experiment is composed of 40 plots (Figure 2; plot dimensions are approximately 2 m by 3 m (6.7 ft by 9.8 ft). A complete randomized block design was applied, with treatments replicated eight times. Monitoring will be conducted during the spring of 2005.