Developing methods of assisted natural regeneration for restoring foundational desert plants

Abstract

Assisted natural regeneration (ANR) is a restoration and management technique for enhancing the natural recruitment of desired species. To test ANR strategies in an arid environment, we applied irrigation and shelters to natural seedlings of the ecologically foundational shrub Larrea tridentata to enhance revegetation of a disturbed site in the Mojave Desert, USA. Irrigation did not improve seedling survival and growth. Shelters reduced 2-year survival by 31% but tripled height growth of surviving seedlings. Utility of shelter for ANR thus hinged on uncertain tradeoffs among seedling survival, height growth, and implementation costs. Mixed results suggest that further evaluating other combinations of treatments and with different species is required to understand ANR’s potential for restoration in arid lands.

Keywords:

• Irrigation
• foundation species
• Larrea tridentata
• Mojave Desert
• protection
• recruitment
• tree shelter

Acknowledgments

We thank the Bureau of Land Management (BLM) California State Office for funding through a cooperative agreement with the University of Nevada Las Vegas; Ramona Daniels and the BLM Needles Office for permits; Carlee Coleman, Matt Rader, Mary Balogh, Mandy Mountain, Audrey Rader, and Shelley Porter for help with experimental set up and monitoring; and two anonymous reviewers for helpful comments on the manuscript.