The Optimization of Life-History Patterns Under Density Dependence

1981 ◽  
Vol 117 (3) ◽  
pp. 403-408 ◽  
Author(s):  
Robert E. Ricklefs
Keyword(s):  
Life History ◽  
Density Dependence ◽  
Life History Patterns

Recognition of larvae of the Tetrabothriidae (Eucestoda): implications for the origin of tapeworms in marine homeotherms

1987 ◽  
Vol 65 (4) ◽  
pp. 997-1000 ◽  
Author(s):  
Eric P. Hoberg
Keyword(s):  
Life History ◽  
Phylogenetic Relationships ◽  
Host Switching ◽  
Larval Morphology ◽  
Dominant Group ◽  
Marine Birds ◽  
Marine Communities ◽  
Definitive Evidence ◽  
Life History Patterns ◽  
Ecological Associations

The Tetrabothriidae represent the dominant group of cestodes, previously known only as adult parasites, in marine birds and mammals. Recognition of their unique plerocercoid larvae provides the first definitive evidence for life history patterns and phylogenetic relationships with other cestodes. Affinities of the Tetrabothriidae and Tetraphyllidea, cestodes of elasmobranchs, are indicated by larval morphology and ontogeny. However, patterns of sequential heterochrony in the ontogeny of the adult scolex of Tetrabothrius sp. appear to be unique among the Eucestoda. Tetrabothriids constitute a fauna that originated by host switching from elasmobranchs to homeotherms, via ecological associations, following invasion of marine communities by birds and mammals in the Tertiary.

scholarly journals Effects of Climate and Biotic Factors on Life History Characteristics and Vital Rates of Yellowstone Cutthroat Trout in Spread Creek, Wyoming

2013 ◽  
Vol 36 ◽  
pp. 160-174
Author(s):  
Patrick Uthe ◽  
Robert Al-Chokhachy
Keyword(s):  
Life History ◽  
Brook Trout ◽  
Cutthroat Trout ◽  
Conservation Strategies ◽  
Snake River ◽  
Vital Rates ◽  
Factors Influencing ◽  
Yellowstone Cutthroat Trout ◽  
Life History Patterns ◽  
Diversity Of Life

The Upper Snake River represents one of the largest remaining strongholds of Yellowstone cutthroat across its native range. Understanding the effects of restoration activities and the diversity of life-history patterns and factors influencing such patterns remains paramount for long-term conservation strategies. In 2011, we initiated a project to quantify the success of the removal of a historic barrier on Spread Creek and to evaluate the relative influence of different climate attributes on native Yellowstone cutthroat trout and non-native brook trout behavior and fitness. Our results to date have demonstrated the partial success of the dam removal with large, fluvial Yellowstone cutthroat trout migrating up Spread Creek to spawn, thus reconnecting this population to the greater Snake River metapopulation. Early indications from mark-recapture data demonstrate considerable differences in life-history and demographic patterns across tributaries within the Spread Creek drainage. Our results highlight the diversity of life-history patterns of resident and fluvial Yellowstone cutthroat trout with considerable differences in seasonal and annual growth rates and behavior across populations. Continuing to understand the factors influencing such patterns will provide a template for prioritizing restoration activities in the context of future challenges to conservation (e.g., climate change).

scholarly journals Are we missing the forest for the trees? Conspecific negative density dependence in a temperate deciduous forest

2021 ◽  
Author(s):  
Kathryn E. Barry ◽  
Stefan A. Schnitzer
Keyword(s):  
Life History ◽  
Density Dependence ◽  
Plant Community ◽  
Plant Diversity ◽  
Temperate Forest ◽  
Woody Plant ◽  
Community Level ◽  
Life History Strategies ◽  
Canopy Trees ◽  
Negative Density Dependence

AbstractOne of the central goals of ecology is to determine the mechanisms that enable coexistence among species. Evidence is accruing that conspecific negative density dependence (CNDD), the process by which plant seedlings are unable to survive in the area surrounding adults of their same species, is a major contributor to tree species coexistence. However, for CNDD to maintain diversity, three conditions must be met. First, CNDD must maintain diversity for the majority of the woody plant community (rather than merely specific groups). Second, the pattern of repelled recruitment must increase in with plant size. Third, CNDD must occurs across life history strategies and not be restricted to a single life history strategy. These three conditions are rarely tested simultaneously. In this study, we simultaneously test all three conditions in a woody plant community in a North American temperate forest. We examined whether the different woody plant growth forms (shrubs, understory trees, mid-story trees, canopy trees, and lianas) at different ontogenetic stages (seedling, sapling, and adult) were overdispersed – a spatial pattern indicative of CNDD – using spatial point pattern analysis across life history stages and strategies. We found that there was a strong signal of overdispersal at the community level. However, this pattern was driven by adult canopy trees. By contrast, understory plants, which can constitute up to 80% of temperate forest plant diversity, were not overdispersed as adults. The lack of overdispersal suggests that CNDD is unlikely to be a major mechanism maintaining understory plant diversity. The focus on trees for the vast majority of CNDD studies may have biased the perception of the prevalence of CNDD as a dominant mechanism that maintains community-level diversity when, according to our data, CNDD may be restricted largely to trees.

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