Agave palmeri Inflorescence Production on Fort Huachuca, Arizona
Abstract
Agave (Agave palmeri) is important to Fort Huachuca because of its status as a critical resource for the lesser long-nosed bat (Leptonycteris curasoae), which was listed as an endangered species in 1988. The bat depends on agave flower nectar as a primary food source in late summer and early fall. Individual plants can live for 25 or more years but flower only once before dying. The basal rosette sends up an inflorescence (a flowering stalk) from 4.5 to 9 m in height and from 7.6 to 15.25 cm in diameter. The inflorescence will comprise more than half the plant's total biomass when fully formed. The plant is already dying by the time seeds are produced. Fort Huachuca contains some of the few remaining roosting sites for this bat in the southwestern United States, and also has abundant agave stands, which are distributed throughout the grasslands. This project was initiated to assess correlates of agave flower production to potentially predict which plants may flower and which will not. A secondary objective of the project was to determine if there are any other impediments to inflorescence production. Plant density data were obtained from 29 randomly chosen flowering plants. Density ranged from 700 to 2200 plants per hectare with approximately 10% flowering stalks. Analysis of the density data indicated that agave plants were significantly and substantially clustered around flowering plants. Individual plants seem to flower based on several criteria, including basal diameter and presence of neighbors. The closer and larger the neighboring agave were, the more likely a particular plant was to flower. Ungulate herbivory affected 50 percent of the agave inflorescences. Given the lack of predators and minimal hunting, herbivore numbers seem likely to increase, putting greater pressure on inflorescence numbers, especially in years when fewer plants flower. Other than the loss of inflorescences, the agave population at Fort Huachuca appears robust and self-sustaining. 7
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2004
- Accession Number
- ADA430808
Entities
People
- Jeffrey S. Fehmi
- Joanne Roberts
- Shelley Danzer
Organizations
- Engineer Research and Development Center