LATE HOLOCENE VS. MODERN ENVIRONMENTS OF CENTRAL MAINE: COMPARISON OF POLLEN, PLANT MACROFOSSIL AND COLEOPTERAN ASSEMBLAGES WITH THE HISTORICAL RECORD

Precise natures of pre-Colonial habitats in North America are important in defining what is environmentally natural. This reports initial results of such a study in central Maine. The Sandy River cutbank study site in Starks, Maine, was sampled for pollen, plant macrofossils, and coleopteran remains. Modern river sediment samples were taken for comparable organic remains. Historical records yielded reliable data for this area from the mid-18th century, predating significant European impacts. Pollen from the sediments is dominated by Tsuga and Betula, with minor Abies and Pinus. Modern river sediment samples show a shift to Betula dominance with decreased Tsuga, Abies and Pinus; Ambrosia, Alnus, Tilia, Thuja, Asteraceae and Poaceae all increase. The plant macrofossil record was dominated by graminoid stems and blades, suggesting the depositional site was an herbaceous marshland devoid of regular flooding. Plant macrofossils from this section add Panicum latifolium type, Carex spp., Scirpus spp., Najas flexilis, Potamogeton spp., Rubus spp., and Sambucus canadensis to the late Holocene flora. The modern river detritus sample, however, was dominated by woody debris, including leaves and seeds of the introduced Acer saccharinum, needles of Abies balsamea, Pinus strobus, Thuja occidentalis & Tsuga canadensis, and macrofossils of Betula populifolia, Quercus rubra, Carex, Scirpus, Najas flexilis and Poaceae. Coleopteran remains were sparse in both the Holocene and modern specimens, but were dominated by remains of Elmidae, Staphylinidae and Carabidae. The Holocene fauna was typified by a greater diversity in Elmids; Carabidae include Bembidion frontale, a species of wet organic substrates, and Agonum extensicolle, of more open sand or gravel; Sphaeroderus lecontei is a forest species. Bembidion castor and Schizogenius sulcifrons in modern detritus are characteristic of open sand and gravel substrates; Xanthania decemnotata feeds on Quercus. Historical records suggest pre-European uplands were pine-dominated, but lowlands by hemlock and cedar, consistent with this study. Macrofossil changes may reflect changes in depositional environment, but are consistent with a shift towards more hardwoods in the post-Colonial forest.