Document: DAV-3-64-16

Herbivory of Ceanothus fendleri: Implications for forest restoration.

HUFFMAN, D.W.* and M.M.MOORE

Northern Arizona University, Flagstaff, AZ 86011, U.S.A. ¹

Abstract:
Treatments to restore ecological conditions of Southwestern ponderosa pine forests, primarily overstory thinning and prescribed burning, have the potential to restore understory plant communities by increasing the availability of resources and facilitating regeneration. However, the role of herbivory in the reestablishment of understory species following restoration activities is largely unknown. To quantify use of a browse species preferred by wild ungulates, we constructed exclosures around 90 Ceanothus fendleri plants in three areas that had been recently thinned according to ecological restoration guidelines. After one growing season, 67% of the aerial shoots produced by unprotected plants had been browsed. Significant (p < 0.001) differences in shoot length and biomass of new growth were found between protected and unprotected plants. Average length of new shoots on protected plants (9.2 cm) was more than three times that of unprotected plants (2.8 cm). Similarly, mean length of the longest shoots produced was 19.5 cm for protected plants and 7.6 cm for unprotected plants. Biomass of new growth on ramets within exclosures was 1.96 g/ramet whereas only 0.66 g/ramet remained on unprotected plants. Total biomass of new growth within exclosures (11.47 g/m²) was nearly four times that of unprotected plants (3.47 g/m²). No differences were found between protected and unprotected plants for the number of new shoots produced (avg. 5.3 shoots/ramet) nor for the number of ramets per plot (avg. 7.5 ramets/m²). Results of this preliminary study indicate the potential of Ceanothus fendleri to respond rapidly when released from overstory interference and browsing pressure. Moreover, herbivory on these sites is an important factor influencing understory structure and rate of recovery following ecological restoration.

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This abstract is being presented at: 10:30 AM in session:
RESTORATION ECOLOGY AND INVASIONS