Early Secondary Succession following Restoration and Reseeding Treatments in Northern Arizona

Reseeding, with and without disc harrowing, building of water bars, and piling of slash on utility corridors (restoration), was studied on access roads and pylon sites following construction of the 500 kV Navajo Project Southern Transmission Line in 1973. Reseeding was not successful. Restoration either had no significant positive effect on revegetation or slowed plant succession in the following Qyear period, or had a deleterious effect on amount and quality of revegetation due to the destruction of climax vegetation which survived powerline construction. Reseeding rangeland has been shown to be both successful and economically feasible by many (e.g. Godfrey 1979, Kearl and Cordingly 1975). Successful seeding, however, has been shown to be dependent upon prevailing weather conditions; weed control (Herbel et al. 1973); seedbed preparation (Struth and Dahl 1974, Hull 1974); and sometimes, pretreatment of seeds to enhance germination (Voigt 1978). In previous papers (Hessing et al. 1981a,b) we described the secondary succession of plants after construction of the 500 kV Navajo Project Southern Transmission Line which connects the Navajo Generating Station at Page, Ariz., with Phoenix. In this paper we describe the effects of reseeding and restoration treatments on the initial course of secondary succession. We used an experimental design which allowed us to describe succession following restoration either separately or together with reseeding. The sequence of powerline construction was that a survey strip was bulldozed in 1972. The powerline was constructed in the spring and early summer of 1973 with part of the survey strip serving as an access road for construction. All restoration and reseeding was done after construction in the summer of 1973. Reseeding occurred at the beginning of the annual summer rainy season, thus providing the seeds with a moist seed-bed.