Publication:
Competitive ability of an epilithic moss, Thuidium tomentosum Schimp., under different light treatments in a subtropical lower montane forest in Puerto Rico

dc.contributor.advisor Sastre-De Jesús, Inés
dc.contributor.author Benavides-Duque, Juan C.
dc.contributor.college College of Arts and Sciences - Sciences en_US
dc.contributor.committee Chinea, Jesús Danilo
dc.contributor.committee Acosta-Mercado, Dimaris
dc.contributor.department Department of Biology en_US
dc.contributor.representative González, Sally
dc.date.accessioned 2018-03-26T15:56:33Z
dc.date.available 2018-03-26T15:56:33Z
dc.date.issued 2007
dc.description.abstract Bryophyte competition in tropical vegetation has been considered a weak shaping drive in the assembly of the communities. Studies on tropical bryophytes considered that changes in species composition are originated mainly by direct interactions with abiotic factors rather than by inter-specific interactions. Here I investigated the competitive ability of Thuidium tomentosum, as well as the importance of its flagelliform branches and the competitive hierarchy with two epilithic bryophyte species: Ceratolejeunea cornuta and Leucoloma cruegerianum. Relative growth rate (RGR) of T. tomentosum was compared across three species combinations, three levels of light (full light, intermediate light and full shade), and two clipping levels (clipped and non–clipped flagelliform branches) during a nine months in a secondary forests of the Ciales municipality. Bryophyte hierarchies were estimated using standardized growth rates during three months in the Toro Negro Commonwealth Forest. Changes in RGR and relative competitive performance (RCP) were analyzed with a mixed model ANOVA for repeated measures. The combination of T. tomentosum with only one of the species showed an effect coherent with the resource competition hypothesis, but the combination of the three species together showed a positive interaction coherent with facilitation hypothesis (F = 8.62, p < 0.001). Light intensity modified the competitive ability of T. tomentosum with higher growth rates under full light and intermediate light than in complete shade (F = 2.76, p = 0.0076). Flagelliform branches seemed to have a role in the lateral expansion of T. tomentosum under different light conditions (F = 3.73, p = 0.025) but did not enhance its competitive ability (F = 0.08, p = 0.98). The competitive ability of T. tomentosum was favored by the presence of C. cornuta and L. cruegerianum and at the same time was reduced in the presence of a sole species. Thuidium tomentosum showed the best competitive performance and was at the top of the hierarchy. Ceratolejeunea cornuta and L. cruegerianum interchanged their role under different light conditions (F = 11.7, p = 0.001) indicating that competition is an important element structuring the epilithic bryophyte communities of mountain forests in Puerto Rico. Changes in the competitive hierarchies across environmental gradients are a new approach to explain the coexistence of numerous bryophyte species in tropical mountains. en_US
dc.description.abstract La competencia en briofitos tropicales ha sido considerada una fuerza débil en la conformación de las comunidades. Los estudios realizados han resaltado la interacción con los factores abióticos más que las interacciones interespecíficas. En este estudio investigue la capacidad competitiva de Thuidium tomentosum, la importancia de sus ramas flageliformes en su capacidad competitiva y la jerarquía competitiva con otras dos especies de briofitos epilíticos,-+ Ceratolejeunea cornuta y Leucoloma cruegerianum. La tasa de crecimiento relativo (RGR) de T. tomentosum fué comparada en tres combinaciones de especies, tres niveles de luz (iluminación completa, iluminación intermedia y sombra), y dos niveles de poda (poda y no poda de las ramas flageliformes) durante nueve meses. Las jerarquías de las tres especies fueron establecidas luego de tres meses de mediciones. Cambios en RGR y desempeño competitivo relativo (RCP) fueron analizados con una ANOVA mixta para medidas repetidas. Las combinaciones de T. tomentosum con solo una de las especies mostró una respuesta acorde a la hipótesis de competencia por recursos con valores inferiores de RGR a los monocultivos, sin embargo la combinación de las tres especies estuvo acorde a la hipótesis de facilitación con tasas de crecimiento similares a los monocultivos (F = 8.62, p < 0.001). La intensidad de la luz afectó el desempeño de T. tomentosum con valores un mejor desempeño en iluminación completa e intermedia que en sombra (F = 2.76, p = 0.0076), evidenciando a T. tomentosum como una especie de zonas abiertas. Las ramas flageliformes aparentemente tienen un papel en la expansión lateral de T. tomentosum (F = 3.73, p = 0.025) pero no incrementan su capacidad competitiva (F = 0.08, p = 0.98). Thuidium tomentosum tuvo siempre un mejor desempeño que las otras dos especies, sin embargo C. cornuta y L. cruegerianum intercambiaban posiciones en su desempeño en diferentes niveles de luminosidad (F = 11.7, p = 0.001), indicando la competencia como un factor importante en la determinación de la composición y estructura de las comunidades de briofitos epilíticos de montaña. Los cambios en las jerarquías competitivas a lo largo de gradientes ambientales son un acercamiento novedoso para explicar la coexistencia de numerosas especies de briofitos en las montanas tropicales. en_US
dc.description.graduationYear 2007 en_US
dc.description.sponsorship Program MARK/SLOAN that funded part of the experimental setting. en_US
dc.identifier.uri https://hdl.handle.net/20.500.11801/308
dc.language.iso en en_US
dc.rights.holder (c) 2007 Juan C. Benavides-Duque en_US
dc.rights.license All rights reserved en_US
dc.subject Bryophyte en_US
dc.subject Thuidium tomentosum en_US
dc.subject Ceratolejeunea cornuta en_US
dc.subject Leucoloma cruegerianum en_US
dc.subject.lcsh Bryophytes--Puerto Rico. en_US
dc.subject.lcsh Forest bryophytes--Puerto Rico. en_US
dc.subject.lcsh Forest plants--Puerto Rico. en_US
dc.subject.lcsh Mosses--Puerto Rico. en_US
dc.subject.lcsh Bryophytes--Toro Negro Forest (P.R.) en_US
dc.title Competitive ability of an epilithic moss, Thuidium tomentosum Schimp., under different light treatments in a subtropical lower montane forest in Puerto Rico en_US
dc.type Thesis en_US
dspace.entity.type Publication
thesis.degree.discipline Biology en_US
thesis.degree.level M.S. en_US
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