Showing papers in "Ecological Monographs in 1967"

Ecological Studies in the Boreal Spruce-Fir Forests of the North American Taiga. I. Analysis of the Vascular Flora

Abstract: 1. STRATIFICATION 231 2. SYSTEMATIC TABULATION 233 3. SPEciEs DIVERSITY BY STAND AND STRATUM. .. 234 4. PRESENCE 234 5. PHYTOGEOGRAPHY . .232 A. Tree Stratum White Spruce-Fir Stands .234 Black Spruce Stands .235 Discussion .236 B. Low Tree-Tall Shrub Stratum White Spruce-Fir Stands .236 Black Spruce Stands .237 Discussion 237 C. Medium and Low Shrub Stratum White Spruce-Fir Stands ...... ......... 238 Black Spruce Stands ....... 239 Discussion . 239 D. Herb-Dwarf Shrub Stratum White Spruce-Fir Stands ...... ......... 239 Black Spruce Stands ....... 241 Discussion . 243 6. PRELIMINARY CLASSIFICATION OF STANDS BASED ON FLORISTIC CRITERIA ..... ......... 243 A. White Spruce-Fir Stand Classification .... 244 B. Black Spruce Stand Classification ....... 246 C. Discussion 247 SUMMARY 249 ACKNOWLEDGMENTS ....... 251 LITERATURE CITED ........ 251 APPENDIXES 252

On the Ecology of the Red Sea Littoral Salt Marsh, Egypt

Abstract: THE PLANT COMMUNITIES 299 I Avicennia marina community 299 II Halocnemon strobilaceum community ....... 299 III Arthrocnemon, glaucum community ........ 300 IV Halopepltis perfoltiata community 301 V Limonium pruinosum community 302 VI Limonium axtllare community 302 VII Aeluropus sp. community 303 VIII Sporobolus spicatus community 304 IX Halopyrum mucronatum community ........ 304 X Zygophyllum album community 305 XI Nitraria retusa community . 306 XII Stuaeda monoica community 307 XIII Tamarix mannifera community 308

Stevens Pond: A Postglacial Pollen Diagram from a Small Typha Swamp in Northwestern Minnesota, Interpreted from Pollen Indicators and Surface Samples

Abstract: The pollen assemblages of a core in the coniferhardwood formation in northwestern Minnesota are compared with the floristics of the recent vegetation in the region. Percentage levels of the main tree components have been compared first with those from recent surface samples taken at the same short distance from various types of upland forests and second with the regional values of the pollen rain in this area (McAndrews 1966). To that end all the data were recalculated on the basis of special pollen sums. The regional diagram of Stevens Pond shows basically the same assemblage zones as established by McAndrews but without the late-glacial Picea-Populus assemblage zone. The pollen in the following Pinus-Pteridium assemblage zone has been interpreted as derived from a pine forest. During the midpostglacial expansion of the prairie eastwards the regional vegetation must have been a Quercus savanna, locally with prairie. Corylus reaches relatively high percentages in this zone. Among the prairie elements especially the occurrence of Lilium philadelphicum may be noted. In the next zone the pollen diagram shows a rise of the curves of mesic elements. In spite of this the comparison with recent surface samples indicates a xerophytic Quercus forest rather than a mesophytic deciduous forest. In the following Pinus assemblage zone pine was present along the margin of Stevens Pond and is therefore overrepresented in the diagram. In the uppermost zone the pollen curves show the effect of logging of the forest about 1900. Pollen of cultivated and introduced plants appear in this zone. Many local pollen types were found, on account of local overrepresentation. This made it possible to compare the local Stevens Pond sequence with the composition of recent lowland vegetation types. The pollen sequence was similar to a large extent to the recent pattern of lake filling, starting with a eutrophic vegetation of Typha latifolia and Salix in the prairie period and leading to a Larix forest and then to a mesotrophic Picea mariana forest, the present edaphic climax on peaty soils. There is a delay, however, in the introduction of acidophilous species, the Larix forest being without Sphagnum and Ericaceae. This is explained by assuming an influence of the vegetation of the surrounding slopes upon the local vegetation. About 1900 the bog forest was destroyed by logging operations and replaced by the present Typha latifolia mat.

Effects of chronic gamma radiation on the structure and diversity of an oak- pine forest.

Abstract: INTRODUCTION 53 OBJECTIVES 54 METHODS 54 DESIGN OF THE EXPERIMENT ...... 54 SIZE AND ARRANGEMENT OF THE PERMANENT PLOTS 55 DOSIMETRY 55 VEGETATION SURVEY ........ 55 RESULTS 56 STRUCTURE OF THE OAK-PINE FOREST .... ........ 56 ZONATION OF VEGETATION AFTER IRRADIATION ..... 56 Devastated zone ........ 57 Carex zone 57 Shrub zone 57 O ak f orest 59 Oak-pine f orest 59 SPECIES DIVERSITY ......... 59 MORTALITY OF TREES ......... 60 Tree survival and radiation exposure . 60 Effects on crown condition .61 Relationship between mortality and size of trees 62 DISCUSSION .64 RADIATION EFFECTS ON STRUCTURE. OF THE POREST 64 DIVERSITY AND ABUNDANCE .65

Structure, Stability, and Energy Flow in Plants and Arthropods in a Sericea Lespedeza Stand

Abstract: The primary purpose of this investigation was to examine energy flow of plants and arthropods in the herb stratum of a sericea lespedeza stand [Lespedeza cuneata (Dumont) G. Don]. The study was conducted on the Atomic Energy Commission Savannah River Plant, Aiken, South Carolina, in 19591960 as a part of ecological research being carried out by University of Georgia staff and students. The lespedeza stand chosen for study was uniform in appearance, stable from year to year, and essentially a monophytic community (composed of but one species of plant). Herb stratum animals were primarily adult arthropods which simplified sampling and taxonomic classification. Simultaneous studies of energy flow, species diversity, and species similarity undertaken at regular collecting periods permitted examination of: (1) the effect of insect populations undisturbed by man on their plant food supply, (2) the regulation of species in stable communities, and (3) the comparison of heterotrophic populations in a monophytic community in regard to interrelationships of species diversity, density, and stability. I wish to express my appreciation to Dr. Eugene P. Odum who directed the study and to Dr. Frank B. Golley both of whom have been most generous with advice and criticism throughout the course of this study. I also wish to thank Dr. D. A. Crossley and Dr. Stanley I. Auerbach of the Radiation Ecology Section, Health Physics Division, Oak Ridge

Comparative Physiological Ecology of the Genus Eriogonum in the Santa Monica Mountains, Southern California

Abstract: The genus Eriogonum Michx., a North American member of the Polygonaceae, has its greatest concentration of species in the drier parts of the western United States and northern Mexico. The species offer a dramatic example of adaptive radiation in the diverse growth forms they assume and the varied habitats they occupy. In California alone there are over 75 species, both annuals and perennials, which occur from coastal bluffs to alpine tundra and in the most severe deserts. On the Santa Monica Mountains of southern California, there are seven closely related species of Eriogonum all of which belong to the subgenus, Oregonium (Munz & Keek 1959). This mountain range offers a variety of habitats with different climates where adaptive radiation is apparent in Eriogonum, although on a smaller scale than that which is evident in the genus as a whole. Some of the species occupy very limited habitats; others are seemingly habitat indifferent. Torrey and Gray monographed the genus Eriogonum in 1870. Then, in 1936, Susan Stokes published a revision emphasizing geographical distribution and probable paleohistory of the group. She divided the genus into four subgenera corresponding to the four main geographical areas of distribution of the genus during the postglacial era. Stebbins

Production of Juvenile Steelhead Trout in a Freshwater Impoundment

Abstract: The purpose of this study was to investigate the population dynamics of juvenile steelhead trout (Salmo gairdneri Richardson) in an artificial freshwater impoundment of 13.3 hectares situated in Western Oregon. Data were collected from May 1962 until May 1963. The specific objectives of the investigation were (a) to determine the limnological characteristics of the pond, and (b) to make a detailed study of the dynamics of survival, growth, and production of the fish population. In the study of fish population dynamics, data were obtained on population size, growth and mortality rates, net production, and total yield. The feeding habits of the fish were studied and related to the standing crop estimates of the available food organisms. The concept of rearing fingerling steelhead trout and Pacific salmon (Oncorhynchus spp.) in controlled impoundments is relatively new. It originated a few years ago in the northwestern regions of the United States as a reaction against the increasing civilization pressure on the natural areas suitable for salmonid production. Fresh and saltwater areas were set aside for producing smolts in one-year cycles.