Plant Population Biology Research Articles

TOPICS IN PLANT POPULATION BIOLOGY

EvolutionVolume 34, Issue 2 p. 407-408 Book ReviewFree Access TOPICS IN PLANT POPULATION BIOLOGY† S. J. McNaughton, S. J. McNaughton Biological Research Laboratories, Syracuse University, Syracuse, New York, 13210Search for more papers by this author S. J. McNaughton, S. J. McNaughton Biological Research Laboratories, Syracuse University, Syracuse, New York, 13210Search for more papers by this author First published: March 1980 https://doi.org/10.1111/j.1558-5646.1980.tb04828.x †Topics in Plant Population Biology. Edited by Otto T. Solbrig, Subodh Jain, George B. Johnson, and Peter H. Raven. Columbia University Press, New York, 1979. 589 pp. $25.00. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume34, Issue2March 1980Pages 407-408 RelatedInformation

Topics in Plant Population Biology.

Topics in Plant Population Biology.

Sex ratio and niche differentiation in spinach (Spinacia oleracea L.)

Studies on the population biology of dioecious plants have concentrated on deviations from the expected sex ratio of 1:1 (refs 1–4) and on sexual imorphism5–10. Sexual dimorphism may imply that the two sexes have different ecologies and this has been demonstrated for a number of animals11. Clearly, if males and females occupy at least partially different niches, competition between members of the two sexes will be reduced and observed sex ratios may be biased by the relative carrying capacities of the two niches. Putwain and Harper12 described differences in the seasonal patterns of growth of males and females in Rumex acetosa and Rumex acetosella and Freeman et al. 13 showed that the males of five dioecious plant species in northern Utah were more abundant on xeric microsites, while females were over-represented in the moister regions of each local environment. We report here that the growth of male and female plants of the annual Spinacia oleracea L. var. Viking is affected differently by population density, and this is reflected in the sex ratio.

The Population Biology of Plants with Clonal Growth: I. The Morphology and Structural Demography of Carex Arenaria

(1) The structural demography of the rhizomatous sand sedge, Carex arenaria L., was studied in two dune-slack systems on Anglesey, North Wales. Carex arenaria was chosen as a model species, since any study of rhizomes is easier when plants grow in loose-textured substrates such as dune sand. (2) A distinctive architectural feature of this plant is the longevity of the rhizome system. Clonal growth by C. arenaria results in subpopulations of shoot modules (tillers) which may be separated into distinct growth phases in the field (juvenile, adolescent, mature, senile and slack). (3) Field plots were established in the mature, senile and slack phases of natural populations; half the plots received a massive nutrient application of NPK fertilizer. The shoot populations within permanent quadrats were mapped at frequent intervals. (4) Recruitment and death of tillers of C. arenaria occurred throughout the year, although the birth and death rates were both highest during the summer. The spring and summer cohorts were generally larger and had lower survivorship. Most of the flowering shoots were derived from shoot cohorts produced during the previous spring and summer. (5) Life expectancy of tillers differed little between the mature and senile phases, but was considerably less in the slack phase. (6) Nutrient application increased the density of shoot populations in the mature and senile phases, but even more striking was the speeding-up of the flux of shoot turnover. The mortality risk within individual cohorts was increased by adding nutrients. Survivorship curves were generally negatively skewed (Deevey Type I) though some maintained a constant death risk (Deevey Type II). Added nutrients changed the age structure of the shoot population to a more juvenile-dominated state. (7) The flux in the shoot populations in the slack phase was sluggish in response to applications of nutrients, probably because this phase was associated with abundant vegetation of other species which absorbed the applied nutrients.

Population Biology of Plants.

Population Biology of Plants.

Topics in Plant Population Biology.

Topics in Plant Population Biology.

Plant Population Biology at the Crossroads.

Plant Population Biology at the Crossroads.

PLANT POPULATION BIOLOGY AT THE CROSSROADS

EvolutionVolume 32, Issue 3 p. 691-692 Book ReviewFree Access PLANT POPULATION BIOLOGY AT THE CROSSROADS† Stephen G. Weller, Stephen G. Weller Department of Biological Sciences, University of Illinois, Chicago, IllinoisSearch for more papers by this author Stephen G. Weller, Stephen G. Weller Department of Biological Sciences, University of Illinois, Chicago, IllinoisSearch for more papers by this author First published: September 1978 https://doi.org/10.1111/j.1558-5646.1978.tb04620.xCitations: 1 †Plant Population Biology at the Crossroads. Systematic Botany 1:201-326. 1976. $4.00 American Society of Plant Taxonomists, Kansas State University, Manhattan, KS 66506. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume32, Issue3September 1978Pages 691-692 RelatedInformation

Population Biology of Plants.

Population Biology of Plants.

Plant Ecology: Matters of Numbers: Population Biology of Plants . John L. Harper. Academic Press, New York, 1977. xxvi, 892 pp., illus. $58.60.

Plant Ecology: Matters of Numbers: <i>Population Biology of Plants</i> . John L. Harper. Academic Press, New York, 1977. xxvi, 892 pp., illus. $58.60.

REVIEWS

Books reviewed in this article: Population Biology of Plants. By John L. Harper. Hybridization and the Flora of the British Isles. Ed. by C. A. Stace. Die Orchideen. By Rudolf Schlechter. Encyclopedia of Plant Physiology, New Series Vol. 5. Photosynthesis I. Photosynthetic Electron Transport and Photophosphorylation. Edited by A. Trebst and M. Avron. Introduction to Ecological Biochemistry. By J. B. Harborne. Plant Growth Regulation. Ed. by P. E. Pilet. Water in Plants Bibliography. Volume 1‐1975. Ed. by J. Pospisilova and J. Solarova. Seaweeds. A Color‐coded, Illustrated Guide to Common Marine Plants of the East Coast of the United States. By C. J. Hillson.

Population Biology of Plants, by John L. Harper. Academic Press: New York–London–San Francisco: xxiv + 892 pp., 23.5 × 15 × 5 cm, £ 30, 1977.

Population Biology of Plants, by John L. Harper. Academic Press: New York–London–San Francisco: xxiv + 892 pp., 23.5 × 15 × 5 cm, £ 30, 1977.

Best kind of Natural History

Population Biology of Plants. By John L. Harper. Pp. xxiv+892. (Academic: London, New York and San Francisco, 1977.) £30; $58.60.

The Prospective Role of Mathematical Theory in Plant Ecology

Despite the recent flowering of mathematical theory in animal ecology, comparable developments in plant population biology are few. Most theory in animal ecology presumes uniform mixing of individuals and, consequently, spatially homogeneous populations. This assumption, which some animal ecologists can scarcely tolerate, is wholly inappropriate for plants. The simplest relaxations of the assumption of uniform mixing lead either to ad hoc theories that are not easily generalized or to second-order partial differential equations that are susceptible neither to mathematical analysis nor to computer simulation. It is suggested that developing methods to deal with spatial heterogeneity, which is the inevitable consequence of imperfect mixing, is crucial to the useful application of mathematics to plant ecology. From time to time the more theoretically minded sort of zoologist may wonder why there has been no eruption of mathematical theory among plant ecologists to match that which made Hutchinson, MacArthur, and Levins household names in animal ecology. Quite likely, our zoologist is unaware of just how intricate (and how different from the algebra of population growth) the mathematics of plant ecology can be-for example, the methods used to detect environmental gradients and associations or natural groupings of species. Nor is he likely to know the literature on spiral leaf arrangement (Thompson, 1917; Leigh, 1972), unless his bent runs to D'Arcy Thompson and functional anatomy. Even the paper in which Skellam (1951) showed how an inferior competitor might coexist with a superior one that would invariably replace it whenever the two came into contact, is likely to be unfamiliar, and so also the extensions of Leslie's (1945) stable age matrix in which age classes of animals are replaced by size classes of trees (Usher, 1969). No doubt there are other more compelling evidences of botanical expertise in mathematics. But this only sharpens the point of our zoologist's question: Why, despite the high level of mathematical sophistication among certain sorts of botanists and plant ecologists, has there been no pandemic of theory in plant population biology? Is this an accident of history, or is there a message here for the animal ecologist as well? To answer this question, let us consider the way in which animal ecologists typically construct a theoretical basis for their science. We begin with 1 We thank H. R. Pulliam, M. L. Rosenzweig, and Patricia A. Werner for useful discussion. 2 Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ 85721. 3 Smithsonian Tropical Research Institute, Balboa, Canal Zone. This content downloaded from 207.46.13.113 on Thu, 06 Oct 2016 04:33:49 UTC All use subject to http://about.jstor.org/terms 210 SYSTEMATIC BOTANY [Volume 1 the growth of a single species and hence with the logistic equation of Pearl and Verhulst. Suppose that N(t) is the density of animals at time t. Let r be the per capita rate of increase, i.e. births minus deaths, when N(t) is near zero, and let a measure the reduction in r occasioned per unit increase in density. Then, [l/N(t)] [dN(t)/dt] (d log N)/dt r aN. (1) Integration of this expression yields the familiar sigmoid growth curve, with N(t) asymptotically increasing to the equilibrium density,

Some Contributions of Physiological Ecology to Plant Population Biology

Information on the physiological responses of plants, particularly photosynthetic capacity, can be utilized in an integrative manner to predict potential success in habitats where resources are closely defined. This approach has been utilized primarily for interspecific and interpopulation comparisons. Similar studies of withinpopulation physiological variability, which will be demanding, are needed to link the approaches of physiological ecology more closely with those of evolutionary population biology. Physiological ecology is the study of the physiological mechanisms that adapt organisms to their environment. Once understood, the operation of these mechanisms can be,quantitatively related to the environment and hence predictions can be made about the success of a given phenotype in any environment. In the context of population biology the result of a selection experiment in a specified environment could be predicted as indicated in Figure 1. Physiological ecology offers population biology some understanding of the what and why that goes on in the selection environment that is more often than not treated as a black box by population biologists. Unfortunately the physiological ecologist rarely follows through on his predictions and actually tests an ending array of phenotypes for heritable physiological characteristics. Attention is instead focused on learning about the physiological characteristics of the starting array and how these relate to the existing environment. Generally, predictions rather than tests are made of the possible results of new selection. Physiological ecologists study many problems of common interest with population biologists, such as adaptation along environmental gradients, adaptation to fluctuating environments, evolution of optimal forms, and niche separation. The approaches utilized in these studies illustrate more specifically how physiological ecologists contribute to the objectives of population biology. The photosynthetic capacity of plants has been intensively studied by physiological ecologists because this process is so fundamental that the linkage to reproductive success is fairly direct. Thus many of the examples that I give center on the varying photosynthetic capacities of plants. Photosynthesis provides the energy for organisms to engage in the competitive process of gathering water, light, and nutrients. These resources are in turn 1 Appreciation is expressed to the National Science Foundation for the support of many of the studies described here. 2 Biological Sciences, Stanford University, Stanford CA 94305, This content downloaded from 207.46.13.111 on Sun, 07 Aug 2016 06:55:08 UTC All use subject to http://about.jstor.org/terms 270 SYSTEMATIC BOTANY [Volume 1

Predation on Scheelea Palm Seeds by Bruchid Beetles: Seed Density and Distance from the Parent Palm

In a test of the following hypotheses, the first was rejected and the second accepted. Rejected: (1) The farther a freshly cleaned [pile of] palm nut[s] (endocarp) is placed from a fruiting parent, the lower will be the probability of the nut[s'] being found by a bruchid. Accepted: (2) The larger the pile of freshly cleaned nuts at a site where there is no parent the more likely that it will be found by bruchids. The study was carried out in a palm forest in Guanacaste Province, Costa Rica, from March until July 1971. In addition to testing the above hypotheses, the study generated natural history data on bruchid oviposition behavior, oviposition intensity, survivorship of the larvae, and developmental rate.