The assessment of clonal diversity in populations of the endemic
Hawaiian coral Porites compressa was undertaken using four independent
assays of genotypic identity: colony morphology, immunocompatibility
testing by tissue grafting, electrophoresis of soluble proteins, and
chromatography of ultra-violet absorbing compounds. All methods were
corroborative, but electrophoresis of soluble proteins provided the
single most efficacious assay of genotypic diversity, with a 7-locus
(21 alleles) system which was estimated to sufficiently resolve approximately
95% of clonal samples.
Populations of Porites compressa were demonstrated to have
derived substantial contributions from both sexual and asexual modes of
reproduction. Sexual reproduction in P. compressa was similar in most
life history parameters to other Porites species that broadcast spawn.
Age at first reproduction was estimated to be between 1.8 and 2.5
years. Mean oocyte diameters were approxiInately 250 um at spawning,
with 10-30 eggs per polyp. Spawning was synchronized with full moon
during summer months, and some colonies spawned over more than one
night and over subsequent months. Planulae were competent to
metamorphose after three days, and sibling juveniles which settled
gregariously were often observed to fuse, suggesting that there may be
ontogenetic changes in self-recognition responses in this species.
Production of asexual propagules by fragmentation was calculated
to be between 35 and 96 fragments/m2/year for a patchreef population of
Porites compressa in Kaneohe Bay, Oahu. Fragment production was
continuous through the year, with a 5-10 fold increase in summer months due pertlaps to increased activity of turtles near sheltering areas on
the reef. Asexual propagules were large (1.5-151 cm2) and survived
for many weeks or months before "recruiting" or being lost from the
fragment pool.
Spatial and/or numeric abundance of dominant and rare clones of
Porites compressa could be explained, in part, by differences in
measurable fitness parameters of growth rate and competitive ability.
No significant differences in the propensity of clones to produce
fragments were detected. The relationship between clonal abundance and
single fitness correlates, however, was not a simple one. Clonal
fitness is the sum of many life history and ecological characteristics
of a genotype. Clonal abundance and distribution may also be effected
by non-selective random physical processes leading to asexual colony
replication and recruitment.
Genotypic diversity in six populations of Porites compressa was
directly related to habitat disturbance histories. Highest diversity
was found in populations which had been intensely or recently disturbed. In these populations, space was not limited and mean colony
size was small (<500 cm2), suggesting an early stage in population
recolonization. In a stable, undisturbed population, low genotypic
diversity revealed the extent of clonal replication of established
genotypes. Unoccupied substratum was rare in this habitat, and
average colony size was larger (>2000 cm2). Single clones were
distributed over small or large areas (<1 to >16 m2) or distances (<1
to >90 m), and were numerically (>13% of total number of colonies) or
spatially (>15% of total colony area) dominant. / Typescript. Thesis (Ph. D.)--University of Hawaii at Manoa, 1988. Includes bibliographical references.
| Identifer | oai:union.ndltd.org:UHAWAII/oai:scholarspace.manoa.hawaii.edu:10125/15322 |
| Date | 01 December 1988 |
| Creators | Hunter, Cynthia L |
| Publisher | University of Hawai'i, Honolulu |
| Source Sets | University of Hawaii at Manoa Libraries |
| Language | en-US |
| Detected Language | English |
| Type | Thesis, Text |
| Format | 148 pages |
| Rights | All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner. |
Page generated in 0.0663 seconds