Conceptual ecological models for the Long Island pitch pine barrens: implications for managing rare plant communities

Abstract

Fire dependent pitch pine (Pinus rigida Mill.) and scrub oak (Quercus ilicifolia Wang.) barrens are found on coarse-textured, droughty soils in the northeastern United States. These communities are globablly rare and, in many areas, dependent on active management to sustain them. We used historic and recent aerial photographs of the Central Pine Barrens in New York to develop transition matrices and trajectories of vegetation change. A vegetation map for 1990 provided pre-burn cover type information for a 1,200 ha area burned by an extremely severe wildfire in August 1995. Geographic information system analyses, a firehistory study, post-wildfire research and existing literature provided additional information for development of three conceptual models that describe our understanding of vegetation change in response to fire and land clearing. A simulation model was then used to predict the amount of each cover type in 2046. The reasonableness of the prediction was assessed based on our understanding of pine barrens vegetation dynamics.In 1938, following a period of frequent, intense wildfires of the region, 90% of vegetation in the study area was open canopy barrens (including dwarf pine plains, pitch pine-scrub oak woodland, heath, pine-heath woodland, and scrub oak shrubland). Between 1938 and 1994, wildfires decreased in size, the average area burned per year generally declined, and there were no fires in 70% of the study area. As a result, barrens decreased to $45% of study area vegetation. In August 1995, an unusually severe summer wildfire converted 810 ha of woodland and forest into scrub oak shrubland, and increased barrens to 60% of study area vegetation. Most areas of heath and pine-heath, which comprised 24% of barrens vegetation in 1996, are successional types that developed on formerly cleared land. In the absence of extensive burning, we expect barrens vegetation to be converted to closedcanopy forest as coppice trees and new seedlings mature. Recent changes in fire regimes are likely to result in a loss of barrens vegetation that exceeds predictions of the simulation model. Careful use of prescribed fire and/or mechanical treatments to simulate the effects of fire are recommended for future restoration and maintenance of pitch pine barrens, and for protection of human life and property. #

Responses of soil carbon, nitrogen and cations to the frequency and seasonality of prescribed burning in a Cape Cod oak-pine forest

“…Fire maintained grasslands and recently-burned pitch pine-scrub oak communities are priorities for conservation in the northeastern U.S., because they are uncommon, declining, and support a number of rare plant and animal species (Schweitzer and Rawinski, 1988;Dunwiddie 4 et al, 1996;Motzkin and Foster, 2002;Wagner et al, 2003). The historical role of fire, recent decreases in fire frequency, fire's association with rare species, and increased risk of large wildfires have led to calls for more prescribed burning for forest and rare species management in the coastal plain region (Patterson et al 1985;Dunwiddie et al, 1997;Jordan et al, 2003).…”

Fire in the Northeast: Learning from the Past, Planning for the Future

“…While grasslands and shrublands may represent an almost entirely human legacy of past land-use, the decline of these habitats from landscapes of the northeastern United States in the modern era represents a loss of rare seral species and regional plant and animal species diversity (Foster & Motzkin, 2003;Jordan, Patterson, & Windisch, 2003;. In response to these conservation concerns, both public and private conservation groups are now actively using fire as a tool for preserving this habitat type (Chandler, King, & Chandler, 2009;Oehler, 2003).…”

Monitoring the effects of gypsy moth defoliation on forest stand dynamics on Cape Cod, Massachusetts: Sampling intervals and appropriate interpretations

“…Depending upon the pre-defoliation condition of the forest, stands reverting to shrublands could have an intermediate woodland phase defined by an open canopy and generally smaller trees, with openings occupied by sedges and ericaceous shrubs. Incorporating fire into a conceptual model of pine-oak forest development has been considered elsewhere (Jordan et al, 2003;Lilly et al, 2004).…”