C.S. Shopmeyer

Bio: C.S. Shopmeyer is an academic researcher. The author has contributed to research in topics: Germination & Woody plant. The author has an hindex of 1, co-authored 1 publications receiving 751 citations.

Ecology of Seed Dispersal

Abstract: Identification of the selective forces on plant dispersal engenders theoretical argument, empirical study, and speculation. We separate evidence, testable hypotheses, and conjecture surrounding two major questions in dispersal ecology. The first asks what ecological, and ultimately evolutionary, advantages exist in seed dispersal. Astonishingly little is known about the advantages to a parent plant that are actually conferred by investment in dispersal structures. Does dispersal enable seeds and ultimately seedlings to escape mortality near the parent? Is continual recolonization of unstable habitats the primary advantage? Must seeds find rare microhabitats suitable for reestablishment? Such issues are addressed through joint consideration of dispersal and establishment-those stages both mediated by parental provisioning and subject to the highest mortality in the life of a plant. The second broad question asks what general and explicit environmental forces influence the timing and mode of dispersal. Do climates or seasons favor one dispersal mode over another? Do differences in number, size, morphology, or nutritional quality of fruits influence frugivore choice, and consequently differential dispersal of species or individuals within species? Studies of dispersal process and mode should be intimately connected. A general objective of this paper is to explore the degree to which they are integrated and, in so doing, to catalyze their union. We emphasize topics most in need of critical attention: the evolutionary ecology of dispersal process and mode. Excellent recent reviews consider such related topics as dispersal mechanism (131, 184), seed dormancy (1, 30), phytogeography (11, 115, 146), masting and predator satiation (105, 156), and succession (68, 69, 189).

The Physiological Ecology of Plant Succession

Abstract: Succession is a process of continuous colonization of and extinction on a site by species populations. The process has long been central in ecological thinking; much theory and many data about succession have accumulated over the years. Since nearly all species in all communities participate in successional interactions, and because physiological ecology encompasses everything that a plant does during its life cycle, a complete review of physiological ecology of all species in all successions is not possible. Thus in this review I discuss the physiological adaptations of species of one successional gradient-from open field to broad-leaved deciduous forest. I concentrate on the physiological adaptations of early successional plants to environmental variability and collate the literature on tree physiology to make comparisons with early successional plants. My discussion may not be applicable to seres where there is little difference in physiognomy between early and late successional plants or where the designation of species as early or late successional is unjustified (e.g. for certain desert and tundra habitats). I discuss the nature of successional environments, seed germination, seedling and mature plant development, plant growth, photosynthesis, water use, and the physiological ecology of competition and interference.

Acclimation and adaptive responses of woody plants to environmental stresses

Abstract: The predominant emphasis on harmful effects of environmental stresses on growth of woody plants has obscured some very beneficial effects of such stresses. Slowly increasing stresses may induce physiological adjustment that protects plants from the growth inhibition and/or injury that follow when environmental stresses are abruptly imposed. In addition, short exposures of woody plants to extreme environmental conditions at critical times in their development often improve growth. Furthermore, maintaining harvested seedlings and plant products at very low temperatures extends their longevity. Drought tolerance: Seedlings previously exposed to water stress often undergo less inhibition of growth and other processes following transplanting than do seedlings not previously exposed to such stress. Controlled wetting and drying cycles often promote early budset, dormancy, and drought tolerance. In many species increased drought tolerance following such cycles is associated with osmotic adjustment that ...

The evolutionary ecology of mast seeding in trees

Abstract: The hypothesis that masting by trees is a defensive strategy which satiates seed predators in mast years and starves them in the intervening periods is tested in 59 sets of data on the seed production and pre-dispersal seed-predation of 25 tree species. Twenty-lour of the 59 data-sets support the hypothesis and show a statistically significant positive relationship between the proportion of seeds surviving the pre-dispersal stage and the log10 of the crop size for the same year. Evidence that pre-dispersal seed survival increases with the length of the mast interval is poor. A positive relationship between the strength of the masting habit and the maxintum observed pre-dispersal seed mortality in a sample of 15 tree species suggests that the masting habit is best developed in predator-prone species. A survey of seed crop frequencies in the woody plant flora of Nortli America shows masting species to be under-represented amongst shrubs and amongst trees which disperse their seeds in fleshy dispersal units. The selection pressures and evolutionary constraints which operate on the evolution of masting plants and their seed predators are discussed.