A test of density-dependent pollination within three populations of endangered Pentachaeta lyonii

Jocelyn R. Holt; Paul Wilson; Christy A. Brigham

doi:10.26786/1920-7603(2014)3

Authors

Jocelyn R. Holt California State University, Northridge
Paul Wilson California State University, Northridge
Christy A. Brigham Santa Monica Mountains National Recreation Area

DOI:

https://doi.org/10.26786/1920-7603(2014)3

Abstract

A major concern with endangered plants is that they might attract insufficient numbers of pollinators, produce low numbers of seeds, and decline towards extinction. We examined effects of density as it varied within populations on the pollination of Pentachaeta lyonii, an endangered species that requires pollinators for seed set. Generalist bee-flies and bees were abundant pollinators at three sites for two years. Per-capita visitation rates did not decline at sparse points or for plants placed on the order of 10 m away from other flowering individuals. Seed production was not pollinator-limited within patches, but seed set was low beyond 10 m from neighbours. Considering prior findings, factors such as habitat loss, competition with alien plants, and poor establishment of new populations likely contribute to the rarity of P. lyonii more than pollination failure.

Author Biographies

Jocelyn R. Holt, California State University, Northridge

M.S. granted

Paul Wilson, California State University, Northridge

Professor of Biology

Christy A. Brigham, Santa Monica Mountains National Recreation Area

Ph.D.; head of resource management.

References

Ashman T-L, Knight TM, Steers JA, Amarasekare P, Burd M, Campbell DR, Dudash MR, Johnston MO, Mazer SJ, Mitchell RJ, Morgan MT, Wilson WG (2004) Pollen limitation of plant reproduction: ecological and evolutionary causes and consequences. Ecology 85:2408-2421. DOI: https://doi.org/10.1890/03-8024

Braker E, Verhoeven L (2000) Relative success of flower visitors in pollination of the endangered Lyon’s Pentachaeta (Pentachaeta lyonii). Lay report. National Park Service, Thousand Oaks, CA.

Braker E, Verhoeven L (2002) Influence of plant neighborhood on pollinator behavior for the endangered Lyon's Pentachaeta (Pentachaeta lyonii). Lay report. National Park Service, Thousand Oaks, CA.

Campbell LG, Husband BC (2007) Small populations are mate-poor but pollinator-rich in a rare, self-incompatible plant, Hymenoxys herbacea (Asteraceae). New Phytologist 174:915-925. DOI: https://doi.org/10.1111/j.1469-8137.2007.02045.x

Caughley G (1994) Directions in conservation biology. Journal of Animal Ecology 63:215-244. DOI: https://doi.org/10.2307/5542

Clements FE, Goldsmith GW (1924) The phytometer method in ecology: the plant and community as instruments. Carnegie Institution of Washington, publication no. 356, Washington, DC. DOI: https://doi.org/10.5962/bhl.title.165873

Conover WJ, Iman RL. 1981. Rank transformation as a bridge between parametric and nonparametric statistics. American Statistician 35:123-129. DOI: https://doi.org/10.1080/00031305.1981.10479327

Courchamp F, Berec L, Gascoigne J (2008) Allee effects in ecology and conservation. Oxford University Press, Oxford, UK. DOI: https://doi.org/10.1093/acprof:oso/9780198570301.001.0001

Courchamp F, Clutton-Brock T, Grenfell B (1999) Inverse density dependence and the Allee effect. Trends in Ecology and Evolution 14:405-410. DOI: https://doi.org/10.1016/S0169-5347(99)01683-3

D’Antonio CM, Vitousek PM (1992) Biological invasions by exotic grasses, the grass/fire cycle, and global change. Annual Review of Ecology and Systematics 23:63-87. DOI: https://doi.org/10.1146/annurev.es.23.110192.000431

Dauber J, Biesmeijer JC, Gabriel D, Kunin WE, Lamborn E, Meyer B, Nielsen A, Potts SG, Roberts SPM, Sōber V, Settele J, Steffan-Dewenter I, Stout JC, Teder T, Tscheulin T, Vavarelle D, Petanidou T (2010) Effects of patch size and density on flower visitation and seed set of wild plants: a pan-European approach. Journal of Ecology 98:188-19. DOI: https://doi.org/10.1111/j.1365-2745.2009.01590.x

Davis FW, Stine PA, Stoms DM (1994) Distribution and conservation status of coastal sage scrub in southwestern California. Journal of Vegetation Science 5:743-756. DOI: https://doi.org/10.2307/3235887

Duncan DH, Nicotra AB, Wood JT, Cunningham SA. 2004. Plant isolation reduces outcross pollen receipt in a partially self-compatible herb. Journal of Ecology 92:977-985. DOI: https://doi.org/10.1111/j.1365-2745.2004.00933.x

Feldman TS (2006) Pollinator aggregative and functional responses to flower density: does pollinator response to patches of plants accelerate at low-densities? Oikos 115:128-140. DOI: https://doi.org/10.1111/j.2006.0030-1299.14493.x

Field DL, Ayre DJ, Whelan RJ (2005) The effect of local plant density on pollinator behavior and the breeding system of Persoonia bargoensis (Proteaceae). International Journal of Plant Sciences 166:969-977. DOI: https://doi.org/10.1086/467473

Forsyth SA (2003) Density-dependent seed set in the Haleakala silversword: evidence for an Allee effect. Oecologia 136:551-557. DOI: https://doi.org/10.1007/s00442-003-1295-3

Fotheringham CJ, Keeley JE (1998) Ecology and distribution of Braunton’s milkvetch (Astragalus brauntonii) and Lyon’s pentachaeta (Pentachaeta lyonii). California Department of Fish and Game. Pp. 1-58, Sacramento, CA.

Gascoigne J, Berec L, Gregory S, Courchamp F (2009) Dangerously few liaisons: a review of mate-finding Allee effects. Population Ecology 51:355-372. DOI: https://doi.org/10.1007/s10144-009-0146-4

Groom MJ (1998) Allee effects limit population viability of an annual plant. American Naturalist 151:487-496. DOI: https://doi.org/10.1086/286135

Groom MJ (2001) Consequences of subpopulation isolation for pollination, herbivory, and population growth in Clarkia concinna concinna (Onagraceae). Biological Conservation 100:55-63. DOI: https://doi.org/10.1016/S0006-3207(00)00207-X

Holt JR (2011) No Allee effects in Lyon’s pentachaeta, a federally listed endangered sunflower. M.S. thesis, California State University, Northridge. Northridge, CA. http://hdl.handle.net/10211.2/684

Keeley JE (1995) Seed germination and dormancy of Pentachaeta lyonii. Final report to California Department of Fish and Game, Sacramento, CA.

Keeley JE (2004) Invasive plants and fire management in California mediterranean-climate ecosystems. In: Arianoutsou M, Papanastasis VP (ed) Proceedings 10th MEDECOS Conference. Mill Press, Rotterdam, Netherlands, pp. 1-10.

Kniskern JM, Rausher MD (2006) Environmental variation mediates the deleterious effects of Coleosporium ipomoeae on Ipomoea purpurea. Ecology 87:675-685. DOI: https://doi.org/10.1890/05-1327

Kunin WE (1997a) Population biology and rarity: on the complexity of density dependence in insect-plant interactions. In: Kunin WE, Gaston KJ (eds) The biology of rarity. Chapman & Hall, London, pp. 150-173. DOI: https://doi.org/10.1007/978-94-011-5874-9_9

Kunin WE (1997b) Population size and density effects in pollination: pollinator foraging and plant reproductive success in experimental arrays of Brasica kaber. Journal of Ecology 85:225-234. DOI: https://doi.org/10.2307/2960653

Lamont BB, Klinkhamer PGL, Witkowski ETF (1993) Population fragmentation may reduce fertility to zero in Banksia goodii—a demonstration of the Allee effect. Oecologia 94:446-450. DOI: https://doi.org/10.1007/BF00317122

Minnich RA, Dezzani RJ (1998) Historical decline of coastal sage scrub in the Riverside-Perris Plain, California. Western Birds 29:366-391.

Moroney JR, Schiffman PM, Brigham CA (2011) Invasive European annual plants impact a rare endemic sunflower. Madroño 58:69-77. DOI: https://doi.org/10.3120/0024-9637-58.2.69

Price MV, Campbell DR, Waser NM, Brody AK. 2008. Bridging the generation gap in plants: pollination, parental fecundity, and offspring demography. Ecology 89:1596-1604. DOI: https://doi.org/10.1890/07-0614.1

Pucci JR (2006) The effects of invasive plants on the endangered sunflower, Pentachaeta lyonii Gray. M.S. thesis. California State University, Northridge. Northridge, CA. http://hdl.handle.net/10211.2/844

Quinn G, Keough M (2002) Experimental design and data analysis for biologists. Cambridge University Press, Cambridge. DOI: https://doi.org/10.1017/CBO9780511806384

Rathcke B (1983) Competition and facilitation among plants for pollination. In: Real L (ed) Pollination biology. Academic Press, Orlando, Florida, pp. 305-329. DOI: https://doi.org/10.1016/B978-0-12-583980-8.50019-3

Rundel PW (2007) Sage scrub. In: Barbour MG, Keeler-Wolf T., Schoenherr AA (eds) Terrestrial vegetation of California. University of California Press Berkeley, CA, pp. 208-228. DOI: https://doi.org/10.1525/california/9780520249554.003.0008

Schulke B, Waser NM (2001) Long-distance pollinator flights and pollen dispersal between populations of Delphinium nuttallianum. Oecologia 127:239-245. DOI: https://doi.org/10.1007/s004420000586

Sih A, Baltus M-S (1987) Patch size, pollinator behavior, and pollinator limitation in catnip. Ecology 68:1679-1690. DOI: https://doi.org/10.2307/1939860

Sokal RR, Rohlf FJ (1995) Biometry, 3rd ed. W. H. Freeman and Company, New York.

Steven JC, Rooney TP, Boyle OD, Waller DM (2003) Density-dependent pollinator visitation and self-incompatibility in upper Great Lakes populations of Trillium grandiflorum. Journal of the Torrey Botanical Society 130:23-29. DOI: https://doi.org/10.2307/3557522

Stephens PA, Sutherland WJ, Freckleton RP (1999) What is the Allee effect? Oikos 87:185-190. DOI: https://doi.org/10.2307/3547011

U.S. Fish and Wildlife Service (1999) Recovery plan for six plants from the mountains surrounding the Los Angeles basin. Portland, Oregon.

Wagenius S, Lyon SP (2010) Reproduction of Echinacea angustifolia in fragmented prairie is pollen-limited but not pollinator-limited. Ecology 91:733-742. DOI: https://doi.org/10.1890/08-1375.1

Widén B (1993) Demographic and genetic effects on reproduction as related to population size in a rare, perennial herb, Senecio integrifolius (Asteraceae). Biological Journal of the Linnean Society 50:179-195. DOI: https://doi.org/10.1006/bijl.1993.1053

Wilson P (1995) Variation in the intensity of pollination in Drosera tracyi: selection is strongest when resources are intermediate. Evolutionary Ecology 9:382-396. DOI: https://doi.org/10.1007/BF01237761