Appendix
Table A1. Age, size, and land-use history of archaeological shell middens analyzed in this study. All dates obtained from Rick et al. (2014)1. We determined site area with subsurface auger excavations, standard excavation units, and surface observations. These values, however, differ from previous site dimensions determined solely by surface observations and reported in site data forms and Rick et al. (2014)1.Cultural periods follow Dent (1995)2. LW=Late Woodland, EW=Early Woodland, CO=Colonial, and HI=Historic.
Site / Age / Cultural Period / Area (m2) / Depth (cmbs)18AN308A / 1250-800 BC / EW / 76 / 0-25
18AN308B / 1250-800 BC / EW / 41 / 0-50
18AN741A / AD 1270-1400 / LW / 26 / 0-26
18AN741B / AD 1270-1400 / LW / 19 / 0-20
18AN226 / AD 1270-1490 / LW / 126 / 0-50
18AN287 / AD 1300-1520 / LW / 41 / 10-65
18AN294 / AD 1460-1630 / LW / 22 / 0-38
18AN854 / AD 1840-1950 / HI / 5 / 0-1
18AN1323 / AD 1860-1950 / HI / 5 / 0-70
18AN296 / AD 1660-1870 / CO/HI / 5 / 0-20
1. Rick, T. C. et al. 2014. Shell middens, cultural chronologies, and coastal settlement on the Rhode River sub-estuary of the Chesapeake Bay, Maryland. Geoarchaeology.
2. Dent, R. J., Jr 1995. Chesapeake Prehistory: Old Traditions New Directions. - Plenum Press.
Table A2: Concentration (ppm for all but pH and cation exchange capacity (MEQ/100G)) of soil chemistry in midden soils and adjacent off-midden areas (means ± 95% C.I.), with significantly higher compounds highlighted in gray. To control for multiple comparisons, we adjusted the p-values (padjusted) using Benjamini and Hochberg’s methods1.
Compound / Midden / Off-midden / t / p-value / padjustedAl / 8.3 ± 2.3 / 283.3± 129.6 / 4.1 / 0.002 / 0.006
B / 1.5 ± 0.6 / 0.5 ± 0.1 / 3.2 / 0.008 / 0.016
Ca / 14300.3 ± 7500.4 / 311.0 ± 315.4 / 3.6 / 0.005 / 0.011
Cd / 0.04 ± 0.03 / 0 ± 0 / 2.4 / 0.036 / 0.052
Cr / 0.01 ± 0.02 / 0.16 ± 0.06 / 4.6 / < 0.001 / 0.006
Cu / 0.87 ± 0.03 / 0.88 ± 0.02 / 0.4 / 0.627 / 0.661
Fe / 1.7 ± 1.2 / 75.0 ± 34.6 / 4.1 / 0.002 / 0.006
K / 219.9 ± 98.6 / 143.4 ± 68.2 / 1.2 / 0.229 / 0.290
Mg / 644.2 ± 392.1 / 255.5 ± 192.6 / 1.7 / 0.104 / 0.141
Mn / 2.4 ± 0.8 / 1.0 ± 0.7 / 2.7 / 0.013 / 0.020
Ni / 0.08 ± 0.03 / 0.11 ± 0.05 / 1.1 / 0.282 / 0.334
NO32- / 28.8 ± 15.4 / 3.8 ± 7.2 / 2.8 / 0.012 / 0.020
P / 2.9 ± 0.7 / 5.6 ± 1.7 / 2.9 / 0.013 / 0.020
Pb / 0.4 ± 0.8 / 2.1 ± 0.5 / 3.4 / 0.002 / 0.006
S / 199.3 ± 64.3 / 30.0 ± 21.3 / 4.8 / < 0.001 / 0.006
Zn / 1.0 ± 0.3 / 1.2 ± 0.3 / 0.5 / 0.560 / 0.625
soil organic matter / 7.5 ± 2.0 / 7.7 ± 7.2 / < 0.1 / 0.983 / 0.983
pH / 7.5 ± 0.2 / 4.4 ± 0.3 / 15.8 / < 0.0001 / 0.001
cation exchange capacity / 63.1 ± 20.1 / 22.2 ± 7.8 / 3.7 / 0.003 / 0.008
1Benjamini Y, Hochberg Y (1995) Controlling the false discover rate: a practical and powerful approach to multiple testing. Journal of the Royal Statistical Society Series B 57:289–300.
Table A3. Species observed in quadrats on and off middens. Information regarding plant origin (N = native, E = exotic/non-native), morphotype, and perenniality (A = annual, B = biennial, P = perennial) derives from the USDA Plants Database (plants.usda.gov). Location refers to whether plants were found exclusively on middens, off middens or on both soil types.
Aceraceae / Acer rubrum / N / P / woody / both
Anacardiaceae / Toxicodendron radicans / N / P / woody / both
Apiaceae / Hydrocotyle verticillata / N / P / forb / both
Aquifoliaceae / Ilex opaca / N / P / woody / both
Asteraceae / Achillea millefolium / E / P / forb / both
Iva frutescens / N / P / woody / both
Berberidaceae / Berberis thunbergii / E / P / woody / both
Bignoniaceae / Campsis radicans / N / P / woody / both
Caprifoliaceae / Lonicera japonica / E / P / woody / both
Viburnum prunifolium / N / P / woody / both
Cornaceae / Cornus florida / N / P / woody / both
Nyssa sylvatica / N / P / woody / both
Cupressaceae / Juniperus virginiana / N / P / woody / both
Cyperaceae / Carex sp. / N / P / graminoid / both
Carex vulpinoidea / N / P / graminoid / both
Dioscoreaceae / Dioscorea villosa / N / P / forb / both
Ebenaceae / Diospyros virginiana / N / P / woody / both
Ericaceae / Kalmia latifolia / N / P / woody / both
Vaccinium corymbosum / N / P / woody / both
Fabaceae / Robinia pseudoacacia / N / P / woody / both
Fagaceae / Fagus grandifolia / N / P / woody / both
Quercus michauxii / N / P / woody / both
Quercus palustris / N / P / woody / both
Quercus prinus / N / P / woody / both
Hamamelidaceae / Liquidambar styraciflua / N / P / woody / both
Juglandaceae / Carya alba / N / P / woody / both
Juncaceae / Juncus tenuis / N / P / graminoid / both
Lauraceae / Sassafras albidum / N / P / woody / both
Liliaceae / Allium vineale / E / P / forb / both
Magnoliaceae / Liriodendron tulipifera / N / P / woody / both
Malvaceae / Hibiscus moscheutos / N / AP / woody / both
Oleaceae / Fraxinus pennsylvanica / N / P / woody / both
Pinaceae / Pinus virginiana / N / P / woody / both
Poaceae / Agrostis gigantea / E / P / graminoid / both
Elymus villosus / N / P / graminoid / both
Festuca rubra / N / P / graminoid / both
Leersia virginica / N / P / graminoid / both
Schedonorus pratensis / E / P / graminoid / both
Sorghum halepense / E / P / graminoid / both
Tripsacum dactyloides / N / P / graminoid / both
Polygonaceae / Polygonum arifolium / N / A / forb / both
Polygonaceae / Polygonum arifolium / N / A / woody / both
Polygonum hydropiperoides / N / P / forb / both
Pyrolaceae / Chimaphila maculata / N / P / woody / both
Rosaceae / Geum canadense / N / P / forb / both
Prunus serotina / N / P / woody / both
Rosa multiflora / E / P / woody / both
Rubus allegheniensis / N / P / woody / both
Rubiaceae / Galium circaezans / N / P / forb / both
Salicaceae / Salix nigra / N / P / woody / both
Smilacaceae / Smilax rotundifolia / N / P / woody / both
Ulmaceae / Ulmus rubra / N / P / woody / both
Vitaceae / Parthenocissus quinquefolia / N / P / woody / both
Vitis labrusca / N / P / woody / both
Aspleniaceae / Asplenium platyneuron / N / P / forb / off
Asteraceae / Baccharis halimifolia / N / P / woody / off
Cyperaceae / Schoenoplectus americanus / N / P / graminoid / off
Lamiaceae / Perilla frutescens / E / A / forb / off
Lauraceae / Lindera benzoin / N / P / woody / off
Poaceae / Distichlis spicata / N / P / graminoid / off
Setaria parviflora / N / P / graminoid / off
Polygonaceae / Rumex acetosella / E / P / forb / off
Rubiaceae / Mitchella repens / N / P / forb / off
Araceae / Arisaema triphyllum / N / P / forb / on
Asteraceae / Antennaria plantaginifolia / N / P / forb / on
Cirsium arvense / E / P / forb / on
Eupatorium serotinum / N / P / forb / on
Solidago bicolor / N / P / forb / on
Solidago sempervirens / N / P / forb / on
Sonchus asper / E / A / forb / on
Taraxacum officinale / E / P / forb / on
Verbesina occidentalis / N / P / forb / on
Caprifoliaceae / Viburnum dentatum / N / P / woody / on
Celastraceae / Celastrus orbiculatus / E / P / woody / on
Chenopodiaceae / Atriplex prostrata / N / A / forb / on
Cyperaceae / Bulbostylis capillaris / N / AP / graminoid / on
Fabaceae / Cercis canadensis / N / P / woody / on
Fagaceae / Quercus ilicifolia / N / P / woody / on
Juglandaceae / Carya cordiformis / N / P / woody / on
Malvaceae / Kosteletzkya virginica / N / P / woody / on
Moraceae / Morus rubra / N / P / woody / on
Onagraceae / Ludwigia alternifolia / N / P / forb / on
Oxalidaceae / Oxalis stricta / N / P / forb / on
Plantaginaceae / Plantago lanceolata / E / ABP / forb / on
Poaceae / Andropogon virginicus / N / P / graminoid / on
Dichanthelium villosissimum / N / P / graminoid / on
Phalaris arundinacea / N / P / graminoid / on
Sphenopholis nitida / N / P / graminoid / on
Rosaceae / Crataegus pruinosa / N / P / woody / on
Rosaceae / Rubus phoenicolasius / E / P / woody / on
Rubiaceae / Galium odoratum / E / P / forb / on
Smilacaceae / Smilax glauca / N / P / woody / on
Figure A1. Changes in species richness and vegetative cover through time. EW refers to the Early Woodland Period (1250-800 BC), LW refers to the Late Woodland Period (AD 1270-1630), and HI refers to the historic and colonial period (AD 1630-1950).