Author
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Brown, John |
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Submitted to: Proceedings of the Entomological Society of Washington
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/20/2000 Publication Date: N/A Citation: N/A Interpretive Summary: The larvae or caterpillars of almost all tortricid moths (leafrollers) are plant-feeding; many are important pests of crops, ornamentals, and forest trees. Because many are host-specific, feeding on only a few different plant species, it is highly likely that changes in the vegetation of an area will lead to changes in the species composition of the resident leafroller fauna. However, this hypothesis has not been tested. Based on historical and current data, Species turnover was examined in the leafroller fauna of Plummers Island, Maryland, a small portion of a natural reserve area along the Potomac River near Washington, D.C. The findings suggest that active management of natural areas may be necessary in order ot maintain species richness and that species that are polyphagous (have many hosts) are more likely to survive thatn those that are specialists. The conclusions will be useful to those involved in conservation planning and in management of nature reserves. Technical Abstract: During the period 1990 through 1999, 114 species of tortricid moths (leafrollers) have been present at one time or another on Plummers Island and the adjacent northern shore of the Potomac River, Maryland. The number of species of leafrollers has declined over the last century from 70 in the decade 1900-1909 to 49 in the decade 1990-1999 - a reduction of 30% in species richness. Of 70 species recorded from the turn of the century, only 28 are still present. With 42 apparent species extinctions and 21 apparent species colonizations, species turnover is 53%. The most likely explanation for changes in the species composition of the site is faunal response and plant community succession. Since the turn of the last century, vegetation of the island has changed from an open juniper grassland to a submature hickory-maple-oak woodland. The adjacent northern shore, likewise, has undergone considerable succession. The hypothesis that changes in the fauna are the result of succession is consistent with the proposal that habitat maturation is the mechanism behind regional declines of several bird and mammal species that require early successional habitat in the northeastern United States. |
