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We investigated the influence of differing patch types on the germination, growth, and survival of two species of tree seedlings in a catastrophic, old-growth forest windthrow. We documented environmental conditions, and experimentally introduced seeds, transplanted seedlings, and manipulated litter and herbivore access to determine the effects of patch types during initial forest regrowth. Among patch types defined by substrate condition and exposure, we found significant differential influence of patch type on germination of seeds of a common colonizer, Betula alleghaniensis. Patch types that provided exposed mineral soil allowed greater germination than other patch types, regardless of light availability. Germination of Acer rubrum varied among patch types in a fashion similar to that of B. alleghaniensis, although differences among patch types were not significant. Litter can also be the basis of patch classification. Both type and amount of litter significantly influenced emergence of seedlings, with broad-leaf litter (in amounts typical of intact forest) producing greater inhibition of emergence than amounts of conifer needles typical of intact forest. Survival and performance of fenced and unfenced Acer rubrum seedlings transplanted into different patch types reflected influences of both herbivory and competition with existing vegetation. Survival was lowest where the Acer seedlings were most apparent to mammalian herbivores. Growth of Acer seedlings was greater when they were protected from herbivory and free of competition from surrounding vegetation. These findings demonstrate that patch types offer different suitability as regeneration microsites during early tree life history stages. Because these patch types are common and easy to recognize, the differences in species' responses may be sufficiently general to apply in other disturbances of this type. If general species responses to patch types can be combined with knowledge of propagule abundance and patch abundance, it could provide a basis for improved understanding of post-disturbance regeneration, via patch influences.

One of the most important ways the discipline of ecology can advance is to facilitate synthesis and integration. In turn synthesis can be stimulated by attending to the cultural factors that promote and constrain the process. Culture refers to special training and development or to the totality of socially transmitted behavior patterns, arts, beliefs, institutions, and all other products of human work and thought. Certain aspects of the general concept of culture can be applied to scientific practice, help explain the role synthesis currently plays in ecology, and identify ways to facilitate synthesis in the discipline. Potential cultural barriers to synthesis include a dominance by narrow, reductive methods without a well-developed counterpoise of integrative and creative habits of mind. The literature on the creative process provides ecologists with a model of the long-term commitment required, the use of analogy and radical juxtaposition, and a vanquishing of the eureka myth. Vertical integration, linkage across a diverse field, cross-disciplinary fertilization, and increased use of the diversity among the community of ecologists can be stimulated by a culture of synthesis.

Ascertaining whether an ecosystem, a community or any other ecological unit has completely changed. whether it has been destroyed or whether it remains the same is a common task for ecologists. At the heart of this task is the question of what constitutes the identity of a unit through time. which we call self-identity. The determination of self-identity requires that we know what the essence of an ecological unit is. This is highly dependent on the definition and specification of the ecological unit of interest, which in turn, depends upon the question(s) being asked. We develop a framework to provide unambiguous definitions of ecological units. The components of this framework are different criteria describing the spatial or process-based boundaries of a unit, the degree of required internal relationship and the level of abstraction t an ecological unit is specified. These criteria can be represented in a three-dimensional graphical model which locates the definitions of ecological units within a conceptual volume. We describe the application of the model for the assessment of the self-identity of ecological units through time. The specification of ecological units and the possibility of assessing the self-identity of ecological objects are also dependent upon the specific ecological theories applied (and upon issues that reside outside the realm of pure ecological science). The universe of meaningful questions and of ecological units is constrained by both societal and scientific interests. We argue that a precise specification of ecological units is necessary for advancing both ecological understanding and its application.

Because the fate of seed rain is critical to understanding the invasion of old fields by trees, we investigated spatial and temporal variation and difference among six tree species in seed predation. Very few Juniperus virginiana seeds were lost to predation but predation for all other test species was reduced by additions of Quercus litter and solidago litter. Carya tomentosa seed predation was also reduced by increasing distance from the forest edge. In addition to litter and distance effects, differing starting densities of Acer rubrum seeds significantly affected predation rates but Fraxinus americana rates were not affected (...)

We studied early soil dynamics, environmental conditions and plant colonization of microsites within 28 recently created treefall pits and mounds in a catastrophic windthrow. Pit and mound sizes were proportional to the size of the fallen trees, and deposition of eroded soil in the center of pits occurred at a decreasing rate over 2 yr. Instability of the substrate contributed to low plant abundance in the pits resulting in lower total plant cover than in the intact soil microsites adjacent to the pits. Larger pits revegetated more slowly than small ones. We recognized four microsites associated with the exhumed roots of each treefall: mound, pit, wall, and intact forest floor (no soil disturbed). Both growth forms and individual species differed in their colonization among microsites, resulting in lower species diversity and total cover on mounds relative to other microsites. Small-seeded, wind-dispersed species colonized the center of pits more readily than species that relied on vegetative spread. Species that are rare in intact forest were common on the disturbed soil of pits and mounds. During two successive years, we documented significant differences among microsites in light, soil moisture, and soil temperature. The species of fallen canopy trees had little influence on the plant community after disturbance, except in the intact soil microsite. We conclude that differential colonization of microsites within forest disturbances occurs at a finer scale than previously recognized and that this facilitates the maintenance of species diversity in the plant community.