Life History and Seed Dispersal of the Short-Lived Chaparral Shrub Dendromecon rigida (Papaveraceae)
1989; Wiley; Volume: 76; Issue: 10 Linguagem: Inglês
10.2307/2444438
ISSN1537-2197
Autores Tópico(s)Botany, Ecology, and Taxonomy Studies
ResumoAmerican Journal of BotanyVolume 76, Issue 10 p. 1506-1517 Article LIFE HISTORY AND SEED DISPERSAL OF THE SHORT-LIVED CHAPARRAL SHRUB DENDROMECON RIGIDA (PAPAVERACEAE) Stephen H. Bullock, Stephen H. Bullock Biology Department, San Diego State University, San Diego, California, 92182 Estación de Biología Chamela, Universidad Nacional Autónoma de México, Apartado Postal 21, 48980 San Patricio, Jalisco, MéxicoSearch for more papers by this author Stephen H. Bullock, Stephen H. Bullock Biology Department, San Diego State University, San Diego, California, 92182 Estación de Biología Chamela, Universidad Nacional Autónoma de México, Apartado Postal 21, 48980 San Patricio, Jalisco, MéxicoSearch for more papers by this author First published: 01 October 1989 https://doi.org/10.1002/j.1537-2197.1989.tb15132.xCitations: 19AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract The natural history of the short-lived, fire-following shrub Dendromecon rigida Benth. was studied with emphasis on reproductive output and the consequences of seed dispersal, by intensive study of one population and comparisons with several others. In 16 populations throughout California, mean seed weight ranged from 10 to 16 mg, and was not correlated with rainfall, elevation or latitude. Seed number per fruit ranged from 3 to 11. Adult populations ranged in size up to several million, but each was probably even-aged, established after recent disturbance. Seed-dispersing ants were found at all localities. Reproduction began one year after establishment. Precocious reproduction did not increase mortality; rather, longer-lived plants were more fecund at all ages. The percentage of the population reproducing and fruit number in the most fecund plants were directly related to rainfall in the preceding six months, regardless of plant age. Reproduction also differed according to topographic position. Mean life expectancy of one-year-old plants was about six years, and only 5% survived to age 10 years. Intraspecific density effects were not apparent. Seed longevity probably exceeds adult longevity by a factor of five or ten. The fruits are explosive and secondary dispersal is by gravity and ants. The ants are attracted to a caruncle which represents 14% of the propagule's caloric content. In the intensive study area ants removed more seeds from more sites than did vertebrate seed predators. Pogonomyrmex subnitidus developed large nests on open sites on ridges, and thus provided uphill (even interdrainage) dispersal; it discarded seeds on the soil surface, free to roll but open to predation. Camponotus species had fewer foragers but many small nests in well-covered sites, and discarded the seeds in underground refuse galleries. Dispersal thus affects exposure to predation, the microsite of germination, conspecific aggregation, and position in the mosaic patterns of topography and fire. Citing Literature Volume76, Issue10October 1989Pages 1506-1517 RelatedInformation
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