Abstract
During 1996 and 1997, two adjacent 2.5 has organic vineyard blocks (A and B) were monitored to assess the distributional and abundance patterns of the Western grape leafhopper Erythroneura elegantula Osborn (Homoptera: Cicadellidae) and its parasitoid Anagrus epos Girault (Hymenoptera: Mymaridae), Western flower thrips Frankliniella occidentalis (Pergande) and generalist predators. The main difference between blocks was that block A was cut across by a corridor composed of 65 flowering plant species which was connected to the surrounding riparian habitat, whereas block B had no plant corridor. In both years, leafhopper adults and nymphs and thrips tended to be more numerous in the middle rows of block A and less abundant in border rows close to the forest and corridor where predators were more abundant. The complex of predators circulating through the corridor moved to the adjacent vine rows and exerted a regulatory impact on herbivores present in such rows. In block B all insects were evenly distributed over the field, no obvious density gradient was detected from the edges into the center of the field. Although it is suspected that A. epos depended on food resources of the corridor, it did not display a gradient from this rich flowering area into the middle of the field. Likewise no differences in rates of egg parasitism of leafhoppers could be detected in vines near the corridor or in the vineyard center. The presence of riparian habitats enhanced predator colonization and abundance on adjacent vineyards, although this influence was limited by the distance to which natural enemies dispersed into the vineyard. However, the corridor amplified this influence by enhancing timely circulation and dispersal movement of predators into the center of the field.
Similar content being viewed by others
References
Altieri, M. A. 1994. Biodiversity and Pest Management in Agroecosystems. Haworth Press, New York, NY, USA.
Baudry, J. 1984. Effects of landscape structure on biological communities: the case of hedgerows network landscapes, Vol. 1. pp. 55–65. In: Methodology in Landscape Ecological Research and Planning. Edited by J. Brandt and P. Agger. Roskilde University Center, Roskilde, Denmark.
Corbett, A. and Rosenheim, J. A. 1996. Impact of natural enemy overwintering refuge and its interaction with the surrounding landscape. Ecol Entomol 21: 155–164.
Corbett, A. and Plant, R. E. 1993. Role of movement in the response of natural enemies to agroecosystem diversification: a theoretical evaluation. Environ Entomol 22: 519–531.
Coombes, D. S. and Sotherton, N. W. 1986. The dispersal and distribution of polyphagous predatory Coleoptera in cereals. Ann Appl Biol 108: 461–474.
Doutt, R. I and Nakata, J. 1973. The Rubus leafhopper and its egg parasitoid: an endemic biotic system useful in grape-pest management. Environ Entomol 2: 381–386.
Duelli, P, Studer, M., Marchand, I. and Jakob, S. 1990. Population movements of arthropods between natural and cultivated areas. Biol Conserv 54: 193–207.
Flaherty, D. L., Christensen, P. T., Lanini, T., Marois, J. and Wilson, L. T. 1992. Grape Pest Management. University of California Division of Agriculture and Natural Resources, Davis, CA, USA.
Fry, G. 1995. Landscape ecology of insect movement in arable ecosystems. In Ecology and Integrated Farming Systems. Edited by D. M. Glen, M. P. Greaves and H. M Anderson. John Wiley and Sons, Bristol, UK, pp. 177–202.
Kido, H.; D. L. Flaherty; D. F. Bosch and K. A. Vaero. 1984. French prune trees as overwintering sites for the grape leafhopper egg parasite. Am J Enol Vitic 35: 156–160.
Lewis, T. 1965. The effects of shelter on the distribution of insect pests. Scientific Horticulture 17: 74–84.
Lys, J. A, Zimmermann, M. and Nentwing, W. 1994. Increase in activity density and species number of carabid beetles in cereals as a result of strip-management. Entomol Exp Appl 73: 1–9.
Murphy, B. C., Rosenheim, J. A. and Granett, J. 1996. Habitat diversification for improving biological control: Abundance of Anagrus epos (Hymenoptera: Mymaridae) in grape vineyards. Environ Entomol 25(2): 495–504.
Nentwing, W., Frank, T. and Lethmayer, C. 1998. Sown weed strips: artificial ecological compensation areas an important tool in conservation biological control. In Conservation Biological Control. Edited by P. Barbosa. AUTHOR, Publisher please, pp. 133–151.
Pollard, E. 1968. Hedges IV. A comparison between the carabidae of a hedge and field site and those of a woodland glade. J Appl Ecol 5: 649–657.
Rosenberg, D. K., Noon, B. R. and Meslow, E. C. 1997. Biological corridors: form, function and efficacy. BioScience 47(10): 677-687.
Settle, W. H. and Wilson, T. 1990. Invasion by the variegated leafhopper and biotic interactions: parasitism, competition, and apparent competition. Ecology 71: 1461–1470.
Sotherton, N.W. 1984. The distribution and abundance of predatory arthropods overwintering on farmland. Ann. Appl. Biol. 105: 423–429.
Thomas, M. B., Wratter, S. D. and Sotherton, N. W. 1991. Creation of ‘islands’ habitats in farmland to manipulate populations of biological arthropods: predator densities and emigration. J Appl Ecol 28: 906–917.
Wratten, S. D. 1988. The role of field margins as reservoirs of natural enemies. In Environmental Management in Agriculture. Edited by A.J. Burn. Belhaven Press, London.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Nicholls, C.I., Parrella, M. & Altieri, M.A. The effects of a vegetational corridor on the abundance and dispersal of insect biodiversity within a northern California organic vineyard. Landscape Ecology 16, 133–146 (2001). https://doi.org/10.1023/A:1011128222867
Issue Date:
DOI: https://doi.org/10.1023/A:1011128222867