The role of sexual reproduction in maintaining populations of Halophila decipiens: implications for the biodiversity and conservation of tropical seagrass ecosystems

1999 ◽  
Vol 5 (4) ◽  
pp. 260 ◽  
Author(s):  
W. Judson Kenworthy
Keyword(s):  
Life History ◽  
Sexual Reproduction ◽  
Clonal Growth ◽  
World Wide ◽  
Vegetative Reproduction ◽  
Indian River Lagoon ◽  
Sexual Life ◽  
Life History Strategies ◽  
Relative Importance ◽  
Seagrass Ecosystems

In subtropical and tropical communities, seagrass species commonly range over an order of magnitude in size and biomass. This biodiversity corresponds with differences in the relative importance of sexual (seed production) and asexual (clonal growth) life history strategies in the maintenance of seagrass populations. Clonal growth and vegetative reproduction are important in maintaining populations of larger-bodied species. As size of species and degree of clonality decrease, the importance of sexual reproduction increases. World-wide, the smallest species in tropical seagrass ecosystems are represented by the most taxonomically diverse, sexually fecund genus, Halophila. A four-year study of the submarine light regime and seasonal growth cycles of Halophila decipiens and other seagrasses in the Indian River Lagoon, Florida, USA provides a comparative context in which to illustrate the relative importance of different life history strategies in tropical seagrass ecosystems world-wide. While sexual reproduction is critical for maintaining some geographically extensive small-bodied seagrass systems in disturbed and extreme environments, there is also evidence to suggest that the quantitative importance of sexual reproduction may be underestimated for larger, highly clonal species like Thalassia testudinum. Future efforts to conserve tropical seagrass ecosystems necessitates a more comprehensive understanding of the evolutionary consequences of sexual reproduction and a more quantitative evaluation of the population dynamics resulting from the sexual life history strategies of different species.

Demography of Xenosaurus platyceps (Squamata: Xenosauridae): a comparison between tropical and temperate populations

2008 ◽  
Vol 29 (2) ◽  
pp. 245-256 ◽  
Author(s):  
Carissa Jones ◽  
Isaac Rojas-González ◽  
Julio Lemos-Espinal ◽  
Jaime Zúñiga-Vega
Keyword(s):  
Life History ◽  
Population Growth ◽  
Adult Mortality ◽  
Life History Strategies ◽  
Relative Importance ◽  
Theoretical Frameworks ◽  
Population Growth Rates ◽  
Relative Contribution ◽  
Two Populations ◽  
Average Fitness

Abstract There appears to be variation in life-history strategies even between populations of the same species. For ectothermic organisms such as lizards, it has been predicted that demographic and life-history traits should differ consistently between temperate and tropical populations. This study compares the demographic strategies of a temperate and a tropical population of the lizard Xenosaurus platyceps. Population growth rates in both types of environments indicated populations in numerical equilibrium. Of the two populations, we found that the temperate population experiences lower adult mortality. The relative importance (estimated as the relative contribution to population growth rate) of permanence and of the adult/reproductive size classes is higher in the temperate population. In contrast, the relative importance for average fitness of fecundity and growth is higher in the tropical population. These results are consistent with the theoretical frameworks about life-historical differences among tropical and temperate lizard populations.

scholarly journals Evolutionary heritage influences Amazon tree ecology

2016 ◽  
Vol 283 (1844) ◽  
pp. 20161587 ◽  
Author(s):  
Fernanda Coelho de Souza ◽  
Kyle G. Dexter ◽  
Oliver L. Phillips ◽  
Roel J. W. Brienen ◽  
Jerome Chave ◽  
...  
Keyword(s):  
Life History ◽  
Evolutionary History ◽  
Large Scale ◽  
Phylogenetic Signal ◽  
Life History Strategies ◽  
Relative Importance ◽  
Life History Variation ◽  
Trait Variation ◽  
Closed Canopy ◽  
Repeated Evolution

Lineages tend to retain ecological characteristics of their ancestors through time. However, for some traits, selection during evolutionary history may have also played a role in determining trait values. To address the relative importance of these processes requires large-scale quantification of traits and evolutionary relationships among species. The Amazonian tree flora comprises a high diversity of angiosperm lineages and species with widely differing life-history characteristics, providing an excellent system to investigate the combined influences of evolutionary heritage and selection in determining trait variation. We used trait data related to the major axes of life-history variation among tropical trees (e.g. growth and mortality rates) from 577 inventory plots in closed-canopy forest, mapped onto a phylogenetic hypothesis spanning more than 300 genera including all major angiosperm clades to test for evolutionary constraints on traits. We found significant phylogenetic signal (PS) for all traits, consistent with evolutionarily related genera having more similar characteristics than expected by chance. Although there is also evidence for repeated evolution of pioneer and shade tolerant life-history strategies within independent lineages, the existence of significant PS allows clearer predictions of the links between evolutionary diversity, ecosystem function and the response of tropical forests to global change.

Size dependency of sexual reproduction and of clonal growth in two perennial plants

1995 ◽  
Vol 73 (11) ◽  
pp. 1831-1837 ◽  
Author(s):  
Bernhard Schmid ◽  
Fakhri A. Bazzaz ◽  
Jacob Weiner
Keyword(s):  
Sexual Reproduction ◽  
Clonal Growth ◽  
Vegetative Reproduction ◽  
Solidago Canadensis ◽  
Threshold Size ◽  
Size Dependency ◽  
Allocation Patterns ◽  
Highly Correlated ◽  
Size Threshold ◽  
Sexual Reproductive Allocation

We compared the size dependency of sexual reproduction and clonal growth in two clonal perennials that inhabit old fields, Aster lanceolatus and Solidago canadensis. In both species there was a threshold size required for sexual reproduction to occur, and above that threshold reproductive output increased linearly with vegetative mass. Biomass allocated to clonal growth was also highly correlated with vegetative mass in both species, but there was no evidence of a threshold size for clonal growth. The absence of a clear size threshold for clonal growth emphasizes the similarity between clonal growth (vegetative reproduction) by rhizomes and growth of other vegetative parts, as opposed to sexual reproductive allocation. In both species there were differences in the allocation patterns of plants derived from seeds and those derived from rhizomes. Although seed- and rhizome-derived plants did not differ in phenology and size, the latter allocated more biomass to sexual reproduction and clonal growth in both species. Key words: clonal growth, size dependency, reproduction, Aster lanceolatus, Solidago canadensis, size threshold.

Distribution and Seasonality of Macroalgae on Oyster Communities of Central Chesapeake Bay

1980 ◽  
Vol 23 (11) ◽  
Author(s):  
Judith L. Connor
Keyword(s):  
Life History ◽  
Sexual Reproduction ◽  
Chesapeake Bay ◽  
Physical Environment ◽  
Algal Species ◽  
Light Availability ◽  
Field Studies ◽  
Spatial And Temporal Distributions ◽  
Red Algal ◽  
Study Sites

AbstractField studies of the benthic macroalgae of fifteen selected Chesapeake Bay oyster communities were conducted over a period of a year (March 1977 to February 1978). Algal distribu tion and seasonal occurrence were studied in relation to changes in the physical environment. Salinity, temperature, and light availability were important factors in the spatial and temporal distributions of algae in these subtidal habitats.Seventeen species of Chlorophyta, Phaeophyta, and Rhodophyta were recorded from the fifteen study sites distributed over 130 kilometers within the Maryland portion of Chesapeake Bay. Species of Chlorophyta were associated with oyster communities throughout the year of study with maximum numbers of species and maximum biomass occurring in spring. Only once was a member of the Phaeophyta encountered; a single filamentous species, Ectocarpus, was collected during winter. Species of Rhodophyta were present throughout the year at the study sites.Most of the algae collected reproduced asexually by spores and/or vegetative fragments. Sexual reproduction occurred in some of the red algal species. The presence of tetrasporic and cystocarpic plants of Dasya baillouviana and Polysiphonia harveyi var. olneyi may indicate that the usual triphasic Florideophycean life history occurs in this estuary.

scholarly journals Natural variation in plant telomere length is associated with flowering time

2021 ◽  
Author(s):  
Jae Young Choi ◽  
Liliia R Abdulkina ◽  
Jun Yin ◽  
Inna B Chastukhina ◽  
John T Lovell ◽  
...  
Keyword(s):  
Life History ◽  
Telomere Length ◽  
Flowering Time ◽  
Dna Sequences ◽  
Genome Wide Association Study ◽  
Genomic Analysis ◽  
Life History Strategies ◽  
Length Variation ◽  
Chromosomal Structure ◽  
Chromosome Integrity

Abstract Telomeres are highly repetitive DNA sequences found at the ends of chromosomes that protect the chromosomes from deterioration during cell division. Here, using whole genome re-sequencing and terminal restriction fragment assays, we found substantial natural intraspecific variation in telomere length in Arabidopsis thaliana, rice (Oryza sativa), and maize (Zea mays). Genome-wide association study (GWAS) mapping in A. thaliana identified 13 regions with GWAS-significant associations underlying telomere length variation, including a region that harbors the telomerase reverse transcriptase (TERT) gene. Population genomic analysis provided evidence for a selective sweep at the TERT region associated with longer telomeres. We found that telomere length is negatively correlated with flowering time variation not only in A. thaliana, but also in maize and rice, indicating a link between life history traits and chromosome integrity. Our results point to several possible reasons for this correlation, including the possibility that longer telomeres may be more adaptive in plants that have faster developmental rates (and therefore flower earlier). Our work suggests that chromosomal structure itself might be an adaptive trait associated with plant life history strategies.

scholarly journals Inconclusive evidence of sexual reproduction of invasive Halophila stipulacea: a new field guide to encourage investigation of flower and fruit production throughout its invasive range

2020 ◽  
Vol 63 (6) ◽  
pp. 537-540
Author(s):  
Fee O.H. Smulders ◽  
Kelcie L. Chiquillo ◽  
Demian A. Willette ◽  
Paul H. Barber ◽  
Marjolijn J.A. Christianen
Keyword(s):  
Sexual Reproduction ◽  
Clonal Growth ◽  
Large Scale ◽  
Fruit Production ◽  
Morphological Evidence ◽  
Invasive Range ◽  
Reproductive Structures ◽  
Halophila Stipulacea ◽  
The Caribbean ◽  
Low Rate

AbstractThe dioecious seagrass species Halophila stipulacea reproduces mainly through fast clonal growth, underlying its invasive behavior. Here, we provide morphological evidence to show that the first findings of fruits in the Caribbean were misidentified. Consequently, H. stipulacea reproduction is likely still only asexual in the Caribbean. Therefore, we introduce an identification key of H. stipulacea reproductive structures to encourage careful identification and quantification throughout its invasive range. Until large-scale seed production in invaded habitats is reported, the apparent low rate of sexual reproduction needs to be considered in current studies investigating the invasion capacity of this species.

Intraspecific hybridization, life history strategies and potential invasion success in a parasitoid wasp

2012 ◽  
Vol 26 (6) ◽  
pp. 1311-1329 ◽  
Author(s):  
Chiara Benvenuto ◽  
Sandrine Cheyppe-Buchmann ◽  
Gérald Bermond ◽  
Nicolas Ris ◽  
Xavier Fauvergue
Keyword(s):  
Life History ◽  
Parasitoid Wasp ◽  
Invasion Success ◽  
Life History Strategies ◽  
Intraspecific Hybridization
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