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Calystegia collina

About: Calystegia collina is a research topic. Over the lifetime, 6 publications have been published within this topic receiving 268 citations.

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Journal ArticleDOI
TL;DR: The findings demonstrate that the size of habitat may have strong effects on the reproductive success of locally endemic plants by enhancing opportu- nities for successful sexual reproduction and warn against the presumption that naturally patchy plant species are invulnerable to the effects of habitat fragmentation.
Abstract: We examined the effects of habitat area and patch isolation on reproductive success in serpentine morning glory (Calystegia collina (Convolvulaceae)), a primarily self-incompatible clonal plant endemic to serpentine outcrops in northern California's coast ranges. Within a 4000-km2 region, we compared the repro- ductive success of C. collina on 16 small ( 300 ha) outcrops. Flower andfruit produc- tion were significantly higher on large serpentine outcrops than on small outcrops. Fruit production also was positively correlated with the soil's ratio of calcium to magnesium. Successful pollination was positively af- fected by flower density and the number of other flowering patches within 100 m of a C. collina patch. The number of nearby flowering patches was considerably higher on large than on small outcrops. Flowers on large outcrops did not receive significantly more bee visitors than flowers on small outcrops, suggesting that pollination success is related to the quality rather than the quantity of pollen deposited. Fruit production by plants on both small and large outcrops was enhanced by the experimental addition of pollen from other patches, but not by the addition of pollen from the same patch. These findings demonstrate that the size of habitat may have strong effects on the reproductive success of locally endemic plants by enhancing opportu- nities for successful sexual reproduction. They also warn against the presumption that naturally patchy plant species are invulnerable to the effects of habitatfragmentation.

96 citations

Journal ArticleDOI
TL;DR: It is concluded that vegetative reproduction, perhaps coupled with somatic mutation, helps maintain genetic diversity in these isolated but long-lived populations of C. collina, a clonal plant species endemic to serpentine outcrops in northern California.
Abstract: We used enzyme electrophoresis to evaluate genetic diversity in 32 populations of Calystegia collina, a clonal plant species endemic to serpentine outcrops in northern California (USA). Of 34 loci examined 56% were polymorphic, but on average only 17% were polymorphic within local populations. Neither the total number of alleles nor the number of multilocus genotypes differed significantly between populations in small vs. large serpentine outcrops. Genetic and geographic distances between populations were positively correlated, but this relationship was not significantly affected by the isolation of serpentine outcrops. Populations were highly differentiated (Fst 5 0.417) and little genetic variation was explained by geographic region or serpentine outcrop. Observed heterozygosity within populations almost always exceeded Hardy-Weinberg expectations. In many populations, all 30 sample ramets were uniformly heterozygous at one or more loci yet were genetically variable at other loci. These results imply that many C. collina populations originate from one or a few genetic founders, with little recruitment from seeds. Genetic variation within uniformly heterozygous populations must be the product of multiple, closely related founders or somatic mutations within the population. We conclude that vegetative reproduction, perhaps coupled with somatic mutation, helps maintain genetic diversity in these isolated but long-lived populations.

71 citations

Journal ArticleDOI
TL;DR: The reproductive ecology of two endemic plant species on large and small serpentine outcrops are studied, illustrating the need to protect serpentine landscapes that contain multiple local populations and the full range of microhabitats that are inhabited by serpentine endemic plants.

51 citations

Journal ArticleDOI
TL;DR: The findings suggest that plant conservation strategies must take into account the natural distribution of populations, and the effects of habitat fragmentation on C. collina and other plant species that occur naturally in small, discrete patches may be unlike those that have been documented in more recently fragmented species.
Abstract: Conservation of rare plant species often involves small, local populations dispersed within apparently suitable habitat. We used enzyme electrophoresis to study genotypic diversity in 32 populations of Calystegia collina, a self-incompatible clonal plant endemic to serpentine substrate in northern California's Coast Range. Genotypic diversity within a population was a good predictor of seed set by randomly marked flowers. Ramets from the most abundant genotypes in a population were most likely to produce flowers, but flowers from abundant genotypes were less likely to produce seed capsules than were flowers from rarer genotypes. These results are consistent with previous findings that reproductive success in C. collina is limited by the availability of compatible pollen. On small serpentine outcrops supporting only one or two populations, C. collina did not show reduced genotypic diversity or heterozygosity compared with populations on large outcrops supporting many populations. Instead, genotypic diversity and outcrop size had strong but independent influences on reproductive success. Although large serpentine outcrops contain more populations and provide better conditions for flower and seed production, significant diversity of unique genotypes clearly exists in isolated serpentine outcrops. Our findings suggest that plant conservation strategies must take into account the natural distribution of populations. The effects of habitat fragmentation on C. collina and other plant species that occur naturally in small, discrete patches may be unlike those that have been documented in more recently fragmented species. Resumen: La conservacion de plantas raras a menudo implica pequenas poblaciones locales esparcidas en un habitat aparentemente adecuado. Utilizamos electroforesis de enzimas para estudiar la diversidad genotipica de 32 poblaciones de Calystegia collina, una planta auto-incompatible clonal endemica a sustratos serpentinos de la cadena costera del norte de California. La diversidad genotipica dentro de una poblacion fue un buen elemento de prediccion de semillas producidas por flores marcadas aleatoriamente. Ramas de los genotipos mas abundantes en una poblacion tenian mayor probabilidad de producir flores, pero las flores de los genotipos abundantes tenian menor probabilidad de producir capsulas de semillas que las flores de genotipos mas raros. Estos resultados son consistentes con hallazgos anteriores que establecen que el exito reproductivo de C. collina esta limitado por la disponibilidad de polen compatible. En pequenos afloramientos de serpentina que sirven de sustrato para 1–2 poblaciones solamente, Calystegia collina no presento una reduccion en la diversidad genetica ni en la heterocigosidad en comparacion con las poblaciones en afloramientos mayores que sirven de sustrato para varias poblaciones. En cambio, la diversidad genotipica y el tamano del afloramiento tuvieron una influencia fuerte, pero independiente, sobre el exito reproductivo. Aunque los afloramientos grandes de serpentina contienen mas poblaciones y proporcionan mejores condiciones para la produccion de flores y semillas, existe una diversidad significativa de genotipos unicos en afloramientos de serpentina aislados. Nuestros hallazgos sugieren que las estrategias de conservacion de plantas que ocurren naturalmente en pequenos parches discretos deben ser distintas a las que se han documentado para especies fragmentadas mas recientemente.

51 citations

Book ChapterDOI
01 Jan 2000
TL;DR: Direct evidence for local extinction and recolonization was found in five herbaceous species that inhabit serpentine seeps, illustrating the importance of largescale landscape structure for population persistence and community diversity in plants.
Abstract: Serpentine soils in California are patchily distributed at multiple spatial scales and support a distinctive flora. In a region of 10 x 30 km in Northern California, I compared plant species richness on 24 small ( 1 km2) outcrops. For serpentine endemic plants, alpha (local) diversity was lower but beta (differentiation) diversity was higher on small outcrops compared to sites within large outcrops. For alien plants, local diversity was higher on small outcrops than on sites within large outcrops. Experimental work examined mechanisms underlying these patterns. Two alien grasses (Avena fatua and Bromus hordeaceus) appeared to be more prevalent on small outcrops because of edge effects rather than because of habitat quality. One serpentine endemic herb (Calystegia collina) exhibited lower reproductive success on small outcrops, evidently because of a shortage of compatible pollen. Another endemic herb (Helianthus exilis) was absent from small outcrops because of the absence of seeps, a specialized habitat found within large serpentine outcrops. Direct evidence for local extinction and recolonization was found in five herbaceous species that inhabit serpentine seeps. These results illustrate the importance of largescale landscape structure for population persistence and community diversity in plants.

3 citations

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20131
20012
20003