Soil Calcium and Forest Birds: Indirect Links Between Nutrient Availability and Community

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Appendix A. Abundances (number per 50-m radius point count) of Songbirds Observed at 14 Forest Sites in Central Pennsylvania, 2006-2008.

Species / Abundance (SE)
Eastern wood-pewee (Contopus virens) / 0.16 (0.02)
Acadian flycatcher (Empidonax virescens) / 0.13 (0.02)
Blue-headed vireo (Vireo solitarius) / 0.23 (0.03)
Red-eyed vireo (Vireo olivaceus) / 0.93 (0.03)
Black-capped chickadee (Poecile atricapillus) / 0.14 (0.02)
Tufted titmouse (Baeolophus bicolor) / 0.07 (0.02)
White-breasted nuthatch (Sitta carolinensis) / 0.11 (0.02)
Blue-gray gnatcatcher (Polioptila caerulea) / 0.09 (0.02)
Veery (Catharus fuscescens) / 0.05 (0.01)
Hermit thrush (Catharus guttatus) / 0.07 (0.02)
Wood thrush (Hylocichla mustelina) / 0.11 (0.02)
American robin (Turdus migratorius) / 0.07 (0.02)
Ovenbird (Seiurus aurocapilla) / 0.62 (0.04)
Worm-eating warbler (Helmitheros vermivorum) / 0.04 (0.01)
Black-and-white warbler (Mniotilta varia) / 0.05 (0.01)
Common yellowthroat (Geothlypis thrichas) / 0.20 (0.03)
Hooded warbler (Setophaga citrina) / 0.13 (0.02)
American redstart (Setophaga ruticilla) / 0.16 (0.02)
Blackburnian warbler (Setophaga fusca) / 0.08 (0.02)
Chestnut-sided warbler (Setophaga pensylvanica) / 0.06 (0.02)
Black-throated blue warbler (Setophaga caerulescens) / 0.14 (0.02)
Black-throatedgreen warbler (Setophaga virens) / 0.35 (0.03)
Eastern towhee (Pipilo erythrophthalmus) / 0.20 (0.03)
Chipping sparrow (Spizella passerina) / 0.11 (0.02)
Scarlet tanager (Piranga olivacea) / 0.39 (0.03)
Indigo bunting (Passerina cyanea) / 0.07 (0.02)
Brown-headed cowbird (Molothrus ater) / 0.04 (0.01)
American goldfinch (Spinus tristis) / 0.08 (0.02)

Appendix B. Basal Area (m2/ha) of Tree Species Observed at 14 Forest Sitesin Central Pennsylvania, 2006-2008

Tree species / Basal area (SE)
Magnolia acuminata / 0.06 (0.02)
Nyssa sylvatica / 0.69 (0.07)
Sassafras albidum / 0.30 (0.07)
Fagus gradifolia / 0.07 (0.02)
Betula lenta / 0.88 (0.12)
Prunus serotina / 0.08 (0.02)
Amelancheir spp / 0.10 (0.01)
Quercus velutina / 0.77 (0.09)
Quercus rubra / 3.69 (0.20)
Quercus coccinea / 0.12 (0.02)
Quercus montana / 4.80 (0.29)
Quercus alba / 2.66 (0.23)
Liriodendron tulipifera / 0.49 (0.12)
Hamamelis virginiana / 0.17 (0.02)
Carya tomintosa / 0.07 (0.02)
Carya cordiformis / 0.23 (0.03)
Carya ovata / 0.03 (0.01)
Cretaegus spp / 0.01 (0.00)
Cornus florida / 0.07 (0.01)
Acer rubrum / 4.49 (0.23)
Acer pensylvanicum / 0.11 (0.02)
Acer saccharum / 0.23 (0.06)
Fraxinus spp / 0.17 (0.04)
Tsuga canadensis / 0.39 (0.10)
Picea spp / 0.07 (0.04)
Pinus pungens / 0.27 (0.07)
Pinus strobus / 0.72 (0.12)
Carpinus caroliniana / 0.02 (0.01)
Ostrya virginiana / 0.09 (0.02)

Appendix C. Density (stems/point) of Shrub and Sapling Species Observed at 14 Forest Sitesin Central Pennsylvania, 2006-2008

Shrub/sapling species / Density (SE)
Nyssa sylvatica / 0.23 (0.08)
Fagus gradifolia / 1.14 (0.64)
Betula lenta / 1.24 (0.64)
Amelancheir spp / 0.42 (0.10)
Quercus velutina / 0.99 (0.21)
Quercus rubra / 0.81 (0.18)
Quercusmontana / 2.83 (0.56)
Quercus alba / 2.91 (0.82)
Hamamelis virginiana / 3.84 (0.53)
Cornus florida / 0.06 (0.02)
Acer rubrum / 6.46 (1.17)
Acer pensylvanicum / 4.06 (0.79)
Acer saccharum / 0.52 (0.27)
Fraxinus spp / 0.77 (0.22)
Tsuga canadensis / 0.60 (0.26)
Pinus strobus / 1.56 (0.35)
Ostrya virginiana / 2.38 (0.48)
Vaccinium spp / 17.79 (1.83)
Kalmia latifolia / 26.51 (2.70)

Appendix D. Mean Ground Cover of 10 Cover Types Observed at 14 Forest Sitesin Central Pennsylvania, 2006-2008

Category / Percent cover (SE)
Green / 56.8 (1.3)
Grass / 3.6 (0.4)
Shrub / 30.3 (1.4)
Brush / 4.5 (0.2)
Forb / 8.7 (0.7)
Fern / 17.3 (1.6)
Moss / 4.6 (0.4)
Litter / 94.8 (0.6)
Log / 4.7 (0.2)
Rock / 7.3 (0.8)

Appendix E. General Habitat Features Observed at 14 Forest Sitesin Central Pennsylvania, 2006-2008

Category / Value (SE)
Litter depth (mm) / 27.1 (0.5)
O-horizon depth (mm) / 23.6 (1.2)
Soil moisture (0=dry, 1=wet) / 0.63 (0.03)
Slope (degrees) / 8.6 (0.4)
Canopy cover (percent) / 91.6 (0.5)
Canopy height (m) / 22.9 (0.6)
Shrub/sapling diversity (species/point) / 5.0 (0.2)
Shrub/sapling density (stems/point) / 86.5 (4.5)
Tree diversity (species/point) / 9.8 (0.2)
Tree basal area (m2/ha) / 22.0 (0.3)
Conifer basal area (m2/ha) / 1.5 (0.2)
Small trees (stems/point) / 51.6 (3.4)
Medium trees (stems/point) / 47.9 (1.6)
Large trees (stems/point) / 19.0 (0.4)
X-large trees (stems/point) / 6.8 (0.3)

Appendix F. Relationships between vegetation (A. trees, B. shrubs and saplings, C. ground cover, D. vegetation structure) and the first axis of the Canonical Correspondence Analysis related to soil calcium and pH. Species scores indicate where peak abundances of each species occurred. Higher cumulative fit scores indicate a higher proportion of the variance in the species data explained by the axis. Vegetation classifications included: associated with high calcium soils (black squares), associated with low calcium soils (hollow diamonds), and not associated with soil calcium (gray circles). Species codes: ACPE=Acer pensylvanicum, ACRU=A. rubrum, ACSA=A. saccharum, AMEL=Amelancheir spp., BELE=Betula lenta, CACA=Carpinus caroliniana, CACO=Carya cordiformis, CAOV=C. ovata, CATO=C. tomintosa, COFL=Cornus florida, CRET=Cretaegus spp., FAGR=Fagus grandifolia, FRAX=Fraxinus spp., HAVI=Hamamelis virginiana, KALA=Kalmia latifolia, LITU=Liriodendron tulipifera, MAAC=Magnolia acuminata, NYSY=Nyssa sylvatica, OSVI=Ostrya virginiana, PICE=Picea spp., PIPU=Pinus pungens, PIST=Pinus strobus, PRSE=Prunus serotina, QUAL=Quercus alba, QUCO=Q. coccinea, QUMO=Q. montana, QURU=Q. rubra, QUVE=Q. velutina, SAAL=Sassafras albidum, TSCA=Tsuga canadensis, VACC=Vaccinium spp.