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You searched for: Journal name Ecology Remove constraint Journal name: Ecology Publication year rev 8007-1993 Remove constraint Publication year rev: 8007-1993 Source 1993 v.74 no.1 Remove constraint Source: 1993 v.74 no.1
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1. Constant Predator‐Prey Ratios: An Arithmetical Artifact?

Author:
G. Closs; G. A. Watterson; P. J. Donnelly
Source:
Ecology 1993 v.74 no.1 pp. 238-243
ISSN:
0012-9658
Subject:
animal ecology; community ecology; food webs; mathematics and statistics; models; predator-prey relationships; predators
Abstract:
... Analysis of several large collections of food webs has shown that predator—prey ratios tend to be roughly constant at values close to one. We suggest that the constancy of the ratio may simply be an arithmetical artifact, a consequence of the way the ratio is defined. Taxa can be recorded as both predator and prey and, hence, be double counted. In many webs the proportion of species that are doubl ...
DOI:
10.2307/1939518

2. Effect of pH Variation of Interspecific Competition Between Two Species of Hylid Tadpoles

Author:
Susan C. Warner; Joseph Travis; William A. Dunson
Source:
Ecology 1993 v.74 no.1 pp. 183-194
ISSN:
0012-9658
Subject:
Hyla; body size; interspecific competition; interspecific variation; intraspecific competition; metamorphosis; pH; tadpoles
Abstract:
... When species differ in their ability to cope with varying abiotic conditions, a change in an abiotic factor can potentially alter the outcome of biotic interactions. The purpose of this study was to examine this phenomenon. We tested the effects of an abiotic factor (pH) and two biotic factors (intraspecific and interspecific competition) on survival and growth to metamorphosis by larvae of two an ...
DOI:
10.2307/1939513

3. Effects of Shading and Fertilization on Resistance of Winter‐Dormant Birch (Betula Pendula) to Voles and Hares

Author:
Matti Rousi; Jorma Tahvanainen; Heikki Henttonen; Ilari Uotila
Source:
Ecology 1993 v.74 no.1 pp. 30-38
ISSN:
0012-9658
Subject:
Betula pendula; Lepus timidus; Microtus agrestis; biomass; growing season; hares; herbivores; nitrogen fertilizers; palatability; seedlings; shade; voles; winter
Abstract:
... Seedling representing four families of European white birch (Betula pendula) were grown through their first growing season in two fertilization and three shading treatments. The growth responses of seedlings were measured, and after complete winter hardening the basal parts of seedlings were offered to voles (Microtus agrestis) and the top parts of the same seedlings were fed to hares (Lepus timid ...
DOI:
10.2307/1939498

4. Energy Constraints and Ultimate Decisions During Egg‐Laying in the Blue Tit

Author:
Jan-Ake Nilsson; Erik Svensson
Source:
Ecology 1993 v.74 no.1 pp. 244-251
ISSN:
0012-9658
Subject:
Cyanistes caeruleus; Parus; birds; breeding; breeding season; clutch size; eggs; energy; females; hatching; progeny
Abstract:
... In a population of Blue Tits, Parus caeruleus, we performed two different food provisioning experiments; one starting before clutch initiaition and one starting when the first eggs were laid. We assessed the effect of these feeding experiments on four fitness—related factors, viz., laying date, clutch size, egg mass, and onset of incubation. Given that breeding birds are food and energy constraine ...
DOI:
10.2307/1939519

5. Induced Resistance and Plant Density of a Native Shrub, Gossypium Thurberi, Affect Its Herbivores

Author:
Richard Karban
Source:
Ecology 1993 v.74 no.1 pp. 1-8
ISSN:
0012-9658
Subject:
Bucculatrix thurberiella; Gossypium thurberi; field experimentation; herbivores; host plants; induced resistance; insect larvae; insects; plant damage; plant density; population size; shrubs
Abstract:
... This field experiment examined whether early—season damage to a wild, native shrub affected the survival and cumulative numbers over several generations of its most abundant herbivore, Bucculatrix thurberiella. The effects of reduced plant density on these herbivores and possible interactions between density and induced resistance were also considered. Half of the plants were damaged experimentall ...
DOI:
10.2307/1939495

6. Intertidal Community Structure: Space‐Time Interactions in the Northern Gulf of California

Author:
Curtis M. Lively; Peter T. Raimondi; Lynda F. Delph
Source:
Ecology 1993 v.74 no.1 pp. 162-173
ISSN:
0012-9658
Subject:
Chlorophyta; Cirripedia; algae; analysis of variance; community structure; estivation; foraging; limpets; littoral zone; mussels; population density; predation; snails; temporal variation; Gulf of California
Abstract:
... Long—term studies are required for an understanding of how temporal variation and space—time interactions affect the structure of communities. Here we report on a long—term study of the independent effects of, and the interactions among, two sources of temporal variation (seasonal and annual) and two sources of spatial variation for a rocky intertidal community in the northern Gulf of California. ...
DOI:
10.2307/1939511

7. Intraguild Predation and Competition Between Larval Dragonflies: Direct and Indirect Effects on Shared Prey

Author:
Scott Wissinger; Jill McGrady
Source:
Ecology 1993 v.74 no.1 pp. 207-218
ISSN:
0012-9658
Subject:
Anisoptera (Odonata); Zygoptera; aquariums; benthic organisms; field experimentation; foraging; freshwater; larvae; migratory behavior; mortality; mouthparts; ponds; predation; predators
Abstract:
... We conducted manipulative field experiments in artificial ponds to quantify the predatory impact of larvae of a migratory dragonfly (Tramea lacerata) on a common resident dragonfly species (Erythemis simplicicollis), and on damselflies as shared prey of the two dragonflies. We found that the combined predatory effects of these two dragonflies on damselflies were not additive. To determine the unde ...
DOI:
10.2307/1939515

8. Patch‐Size Effects on Plant Phenolics in Successional Openings of the Southern Appalachians

Author:
Donald J. Shure; Lawrence A. Wilson
Source:
Ecology 1993 v.74 no.1 pp. 55-67
ISSN:
0012-9658
Subject:
Acer rubrum; Cornus florida; Liriodendron tulipifera; Robinia pseudoacacia; canopy gaps; carbon; chemical defenses; forests; growing season; leaves; phenotype; phytophagous insects; pioneer species; proanthocyanidins; seasonal variation; shade tolerance; solar radiation; summer; tannins; trees; understory; Appalachian region
Abstract:
... We examined the seasonal changes in plant chemical defenses of key tree species (Robinia pseudoacacia, Liriodendron tulipifera, Acer rubrum, and Cornus florida) regenerating during early succession in different patch sizes within Southern Appalachian forests. Trees of each species were sampled from five sizes of forest openings (0.016, 0.08, 0.4, 2.0, and 10 ha; two replicates each) and from the u ...
DOI:
10.2307/1939501

9. Processes Regulating Soil Emissions of NO and N^2O in a Seasonally Dry Tropical Forest

Author:
E. A. Davidson; P. A. Matson; P. M. Vitousek; R. Riley; K. Dunkin; G. Garcia-Mendez; J. M. Maass
Source:
Ecology 1993 v.74 no.1 pp. 130-139
ISSN:
0012-9658
Subject:
ammonium compounds; carbon dioxide; denitrification; denitrifying bacteria; dry season; environmental factors; field experimentation; gases; greenhouse gas emissions; mineralization; models; nitric oxide; nitrification; nitrites; nitrogen; nitrous oxide; soil water; tropical forests; wet season; Mexico
Abstract:
... While much is known about control of production of NO and N₂O by nitrifying and denitrifying bacteria at the cellular level, application of this knowledge to field studies has not yielded unifying concepts that are widely applicable and that foster understanding of global sources of these atmospheric trace gases. We applied a simple conceptual model to the investigation of sources of NO and N₂O an ...
DOI:
10.2307/1939508

10. Size‐Dependent Competition: Effects on the Dynamics Vs. The End Point of Mussel Bed Succession

Author:
J. Timothy Wootton
Source:
Ecology 1993 v.74 no.1 pp. 195-206
ISSN:
0012-9658
Subject:
Larus; Lepadidae; Mytilus californianus; adults; birds; body size; indeterminate growth; littoral zone; mussels; predation; predators
Abstract:
... I manipulated relative body size of mussels (Mytilus californianus) and gull (Larus glaucescens) predation pressure within gaps in a mussel bed to determine (1) whether size differences could cause shifts in competitive dominance between goose barnacles (Pollicipes polymerus) and Mytilus, species with indeterminate growth, and (2) if the late recruiting Mytilus required gull predation on establish ...
DOI:
10.2307/1939514

11. Ant Lion Zones: Causes of High‐Density Predator Aggregations

Author:
Nicholas J. Gotelli
Source:
Ecology 1993 v.74 no.1 pp. 226-237
ISSN:
0012-9658
Subject:
Myrmeleon; arthropod communities; arthropods; avoidance behavior; cannibalism; cliffs; community structure; field experimentation; food availability; larvae; microhabitats; mortality; pitfall traps; population dynamics; predation; predators; probability; rain; sandstone; seasonal variation; soil crusts; soil water; surface temperature; vegetation; Oklahoma
Abstract:
... In this study, I describe the causes of persistent small—scale zonation in a terrestrial arthropod community. In central Oklahoma, two species of predaceous, pit—building ant lion larvae (Myrmeleon immaculatus and M. crudelis) coexist in a narrow, high—density (>50 animals/m²) zone at the base of sandstone cliffs, where they are sheltered from rain and afternoon sun. Although larval movement is fr ...
DOI:
10.2307/1939517

12. Biomass and Nutrient Dynamics Associated with Slash Fires in Neotropical Dry Forests

Author:
J. Boone Kauffman; Robert L. Sanford Jr.; Dian L. Cummings; I. H. Salcedo; E. V. S. B. Sampaio
Source:
Ecology 1993 v.74 no.1 pp. 140-151
ISSN:
0012-9658
Subject:
aboveground biomass; air pollution; biodiversity; biogeochemical cycles; burning; burning season; calcium; carbon sinks; combustion; deforestation; dry forests; ecosystems; fallow; fire severity; fires; forest soils; leaves; nitrogen; nitrogen content; nutrients; phosphorus; second growth; slash; tropics; wind erosion; wood; Brazil
Abstract:
... Unprecedenteded rates of deforestation and biomass burning in tropical dry forests are dramatically influencing biogeochemical cycles, resulting in resource depletion, declines in biodiversity, and atmospheric pollution. We quantified the effects of deforestation and varying levels of slash—fire severity on nutrient losses and redistribution in a second—growth tropical dry forest ("Caatinga") near ...
DOI:
10.2307/1939509

13. Competitive Effects of Grassland Annuals on Soil Water and Blue Oak (Quercus Douglasii) Seedlings

Author:
Doria R. Gordon; Kevin J. Rice
Source:
Ecology 1993 v.74 no.1 pp. 68-82
ISSN:
0012-9658
Subject:
Bromus diandrus; Erodium botrys; Quercus douglasii; annuals; flowers; forbs; fruits; gas exchange; grasses; grasslands; introduced species; phenology; plant available water; seedling growth; seedlings; soil density; soil water potential; sowing; spring; summer; survival rate; woodlands; California
Abstract:
... Four California annual grassland species were used to examine the hypothesis that different plant species have equivalent competitive effects. We investigated the effects of the annuals on soil water availability and the growth responses of blue oak (Quercus douglasii Hook & Arn.) to neighbor—induced water depletion. Neighborhoods of annuals were composed of species from California annual grasslan ...
DOI:
10.2307/1939502

14. Controls over Nutrient Resorption from Leaves of Evergreen Mediterranean Species

Author:
Francisco I. Pugnaire; F. Stuart Chapin III
Source:
Ecology 1993 v.74 no.1 pp. 124-129
ISSN:
0012-9658
Subject:
leaves; nutrient balance; nutrient resorption (physiology); nutrients; phenotype; phosphorus; proteins; resorption; serpentine; serpentine soils; shrubs; trees; California
Abstract:
... Nutrient resorption from senescent leaves, by minimizing nutrient losses, could be just as important as uptake in determining nutrient balance, especially in low—nutrient environments. To examine the relative importance of phenotypic and genotypic factors in controlling nutrient resorption, we sampled several meditterranean trees and shrubs growing in serpentine and nonserpentine soils in northern ...
DOI:
10.2307/1939507

15. Costs and Benefits of Induced Resistance and Plant Density for a Native Shrub, Gossypium Thurberi

Author:
Richard Karban
Source:
Ecology 1993 v.74 no.1 pp. 9-19
ISSN:
0012-9658
Subject:
Bucculatrix thurberiella; Gossypium thurberi; herbivores; induced resistance; insect larvae; models; plant damage; plant density; plant growth; reproduction; seeds; shrubs
Abstract:
... Many plants employ induced defenses that are activated after attack rather than constitutive defenses that are always present. Current theory predicts that one benefit of induced defenses is to optimize the plant's allocation to defense, growth, and reproduction. According to this reasoning induced defenses are expected under the following conditions: (1) Attack is unpredictable and not fatal. (2) ...
DOI:
10.2307/1939496

16. Effects of Herbivores on Growth and Reproduction of their Perennial Host, Erigeron Glaucus

Author:
Richard Karban; Sharon Y. Strauss
Source:
Ecology 1993 v.74 no.1 pp. 39-46
ISSN:
0012-9658
Subject:
Cercopidae; Erigeron; Thomomys bottae; biomass; buds; corolla; gophers; greenhouse experimentation; herbivores; host plants; insect larvae; leaves; monitoring; mortality; moths; plant growth; pollinators; reproduction; seedlings
Abstract:
... Experiments were conducted over several years to assess the effects of the three most abundant herbivores (a thrips, a spittlebug, and a plume moth) on the growth and reproduction of their long—lived, iteroparous host plant. In a greenhouse experiment, thrips reduced root biomass of seedlings, but not shoot biomass. No correlation was found between density of thirps and change in aboveground area ...
DOI:
10.2307/1939499

17. Gas Exchange Dynamics in C^3 and C^4 Grasses: Consequence of Differences in Stomatal Conductance

Author:
Alan K. Knapp
Source:
Ecology 1993 v.74 no.1 pp. 113-123
ISSN:
0012-9658
Subject:
stomatal movement; carbon dioxide; grasses; C4 plants; simulation models; solar radiation; stomatal conductance; Bromus inermis; water vapor; equations; gas exchange; water use efficiency; cloud cover; shade; photosynthesis; C3 plants; grasslands; stomata; Sorghastrum nutans
Abstract:
... In full sunlight (photosynthetic photon flux density, 0.4—0.7. μm, PPFD), stomatal conductance to water vapor (g) and transpiration rates (E) are usually higher, and water use efficiency lower, in C₃ than C₄ species. In the C₃ grass Bromus inermis, the difference in conductance between full sun (photosynthetic photon flux [PPFD] > 1500 μmol°m— ²°S— ¹) and shade (PPFD ° 400 μmol°m— ²°s— ¹) was twic ...
DOI:
10.2307/1939506

18. Induced Resistance in Ipomoea Purpurea

Author:
Mark D. Rausher; Keisuke Iwao; Ellen L. Simms; Naota Ohsaki; David Hall
Source:
Ecology 1993 v.74 no.1 pp. 20-29
ISSN:
0012-9658
Subject:
Chaetocnema confinis; Deloyala guttata; Ipomoea purpurea; Metriona bicolor; Spodoptera eridania; herbivores; induced resistance; insects; larvae; leaves
Abstract:
... A series of experiments indicate that induced changes occur in the foliage of the annual morning glory Ipomopea purpurea when subjected to prior damage. These changes reduce the growth rate, consumption rate, growth efficiency of larvae of the generalist lepidopteran Spodoptera eridania. They also alter the pattern of damage caused by specialist flea beetles, Chaetocnema confinis, and by generalis ...
DOI:
10.2307/1939497

19. Leaf Decomposition in Two Mediterranean Ecosystems of Southwest Spain: Influence of Substrate Quality

Author:
Antonio Gallardo; Jose Merino
Source:
Ecology 1993 v.74 no.1 pp. 152-161
ISSN:
0012-9658
Subject:
biodegradation; cellulose; cutin; ecosystems; leaching; leaves; lignin; nitrogen; phosphorus; plant litter; shrubs; tannins; trees; Spain
Abstract:
... We studied the influence of litter quality on the decomposition rate of leaves from nine Mediterranean shrubs and trees using litter bag methods for a 2—yr period at two ecosystems in southwest Spain. Linear and nonlinear regressions were calculated between mass loss and the concentrations of the major organic and inorganic constituents of leaves (lignin, cutin, cellulose, tannins, crude fat, solu ...
DOI:
10.2307/1939510

20. Mechanisms Controlling Invasion of Coastal Plant Communities by the Alien Succulent Carpobrotus Edulis

Author:
Carla M. D'Antonio
Source:
Ecology 1993 v.74 no.1 pp. 83-95
ISSN:
0012-9658
Subject:
Carpobrotus edulis; biomass; disturbed soils; germination; gophers; grasses; grasslands; herbivores; introduced plants; plant communities; roots; seedlings; shoots; shrublands; shrubs; species recruitment; California
Abstract:
... The South African succulent Carpobrotus edulis has been invading native and non—native plant assemblages in California since its introduction in the early 1900s. This study was designed to determine mechanisms controlling invasion by this species into three different communities: coastal grassland, backdune, and coastal scrub. The communities differed in several factors that influenced invasion by ...
DOI:
10.2307/1939503