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Harvard Forest Symposium Abstract 2008

  • Title: Moth abundance and diversity in Tom’s Swamp Tract #4 (ts30-a) slated for removal of non-native conifers
  • Primary Author: Mark Mello (Lloyd Center for the Environment)
  • Abstract:

    In order to obtain a measure of habitat utilization by the moth community at Tom’s Swamp Tract #4 (TS30-A), a 47-acre parcel within which removal of non-native conifers is planned, portable quantum UV blacklight traps were operated from dusk to dawn on three nights (July 16, August 2 and September 25, 2007) at three stations established therein. Stations differed somewhat in percent canopy, canopy composition and understory vegetation, but red pine, white pine and/or larch were major components of the canopy each site. All macrolepidoptera (Drepanoidea, Geometroidea, Bombycoidea, Sphingoidea and Noctuoidea) captured were identified and counted.

    A total of 3,537 moths were recorded, comprising 202 species, which likely represents 40-60% of the macrolepidopteran species present at this parcel. Nearly 60% (2,108) of the individuals representing 40% (80/202) of the species are primarily deciduous forest species, particularly second growth forest with a varied understory. Another 769 moths (22%) representing 11% of the species inhabit coniferous forests, and 475 moths (13%) representing 24% of the species are generalists that inhabit forested as well as other habitat types. The remaining 5% of the individuals representing 25% of the species encountered are shrubland, grassland or wetland species that may have traveled from these nearby habitats to the traps. Thus, the overwhelming number of individuals (95%) are primarily or exclusively forest dwellers but as many as 25% of the species are likely transients.

    Although each of the three stations differed somewhat in habitat composition, pair-wise comparisons of the Index of Similarity using t-test on the Shannon-H index of diversity (calculated using PAST) indicated no statistical difference in the diversities between stations: p(1,2) = 0.817; p(2,3) = 0.676; p(1,3) = 0.528. Likewise, a Krushal-Wallis test (calculated using PAST) detected no significant difference (p = 0.5486) in species distribution among stations at the 5% level. I therefore conclude that the entire Tom’s Swamp Tract #4 forms single, but heterogeneous community of forest-dwelling moth species dominated by deciduous forest species.

    Because this data likely represents 50% or less of the entire species composition on site, because light trap effectiveness is highly subject to the vagaries of the weather, and because insect populations are highly volatile in their year to year and seasonal peak abundance, this data is minimally useful in multi-year comparisons of individual species trends. However it is useful in tracking change at the community level post non-native tree removal, particularly in monitoring changes in community diversity and habitat utilization.

  • Research Category: Biodiversity Studies