Technical Report #58. Loope, L. L., and C. F. Crivellone. May 1986. Status of the Silversword in Haleakala National Park: Past and Present
 

26 MB

 

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Abstract: The Haleakala silversword, Argyroxiphium sandwicense DC. ssp. macrocephalum (Gray) Meyrat, declined markedly in the late 1800's and early 1900's due to browsing by goats and cattle and to vandalism by humans. During the 1930s, after protection was provided by the national park, much concern arose over the high level of seed predation by native insects. Nevertheless, following protection, silversword numbers have increased and now total about 50,000 individuals. Although total crater-wide numbers remained stable between censuses in 1971 and 1982, large fluctuations have occurred on individual cinder cones. Plots for long-term study of silversword population dynamics have been established, with data taken annually. Preliminary results after three years suggest that many seedlings establish in some years, few or none in others; that substantial natural mortality occurs in some years; and that wide population fluctuations from year to year are occurring. The greatest threats to the Haleakala silversword today are thought to be the Argentine ant (Iridomyrmex humilis) and the western
yellow-jacket (Vespula pensvlvanica), aggressive alien predators (of insects) which could disrupt ecosystem processes, especially pollination. Park managers now recognize the need
for preservation of the entire complex of organisms belonging to the silversword ecosystem.

Cover, Title page, Frontispiece

3 MB

Abstract

470 KB

Table of contents, list of figures, list of tables

867 KB

Introduction, methods, results and discussion

17 MB

Acknowledgements & literature cited

2.3 MB

Tables

2.6 MB

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