Document: ROB-3-40-19

Relationships among woodland vegetation and land-use history, Cape Cod National Seashore, MA.

EBERHARDT, R.W.*, D.R.FOSTER, G.MOTZKIN, J.HARROD and B.HALL

Harvard Forest, Petersham, MA 01366 ¹

Abstract:
Human land-use affects the composition, structure, and landscape pattern of vegetation worldwide. The specific effects of land-use history on modern vegetation are poorly understood because of complex, yet poorly documented histories of use and frequent correlations of past land-use and environmental gradients. Here we report relationships among modern woodland vegetation and land-use history on 4400 ha of glacial outwash deposits on Cape Cod National Seashore in southeastern Massachusetts. Relatively homogeneous site conditions and the availability of detailed historical information make the study area particularly appropriate for evaluating the effects of land-use history on vegetation. The conservation significance of the site also provides an opportunity to inform management efforts. Colonists settled outer Cape Cod by 1644, and US Coast and Geodetic Survey maps suggest that agriculture/open land covered approximately 48 % of the study area during the mid-nineteenth century. Land abandonment and reforestation followed: based on 1938 aerial photographs and tree ring counts, agriculture/open land covered only 15 % of randomly-chosen modern woodland plots (n = 94) by the mid-twentieth century. Comparison of these historical sources, the presence/absence of plow (Ap) horizons, and quantitative vegetation data show that modern woodland species distributions closely track patterns of land-use history. Clonal shrubs including Gaultheria procumbens, Epigaea repens, Gaylussacia baccata, and Vaccinium spp. are concentrated in areas never plowed for crop cultivation, and species indicative of globally-rare coastal heathlands/grasslands occur preferentially in former croplands, pastures and other previously disturbed areas. This study illustrates the importance of considering human disturbance history in interpretations of modern vegetation and in developing conservation objectives and management guidelines for uncommon species and communities.

Keywords: Cape Cod, conservation, disturbance, heathlands, land-use history, New England, pine barrens, pitch pine, vegetation

This abstract is being presented at: 10:30 AM in session:
Poster Session #5: Landscape Ecology.