AOBPreview published online on August 19, 2004
Annals of Botany, doi:10.1093/aob/mch171
© 2004 by Annals of Botany Company
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Submitted on April 9, 2004
Affiliation of the authors:
1 Laboratorio de Genética de Poblaciones, Departamento de Biología Evolutiva, Instituto de Ecología, A. C. Km 2·5 Antigua Carretera a Coatepec, Xalapa 91070, Veracruz, México;
2 CEAMISH-UAEM, Av. Universidad 1001, Col. Chamilpa, Cuernavaca, Morelos, México
* To whom correspondence should be addressed. E-mail: astorga{at}ecologia.edu.mx.
Background and Aims The monoecious, bird-pollinated epiphytic Tillandsia achyrostachys E. Morr. ex Baker var. achyrostachys is an endemic bromeliad of the tropical dry forests of Mexico with clonal growth. In the Sierra de Huautla Natural Reserve this species shows a host preference for Bursera copallifera (Sessé & Moc ex. DC) Bullock. As a result of deforestation in the study area, B. copallifera has become a rare tree species in the remaining forest patches. This human-induced disturbance has directly affected the population densities of T. achyrostachys. In this study the genetic consequences of habitat fragmentation were assessed by comparing the genetic diversity, gene flow and genetic differentiation in six populations of T. achyrostachys in the Sierra de Huautla Natural Reserve, Mexico. Methods Allozyme electrophoresis of sixteen loci (eleven polymorphic and five monomorphic) were used. The data were analysed with standard statistical approximations for obtaining diversity, genetic structure and gene flow. Key Results Genetic diversity and allelic richness were: HE = 0·21 ± 0·02, A = 1·86 ± 0·08, respectively. F-statistics revealed a deficiency of heterozygous plants in all populations (Fit = 0·65 ± 0·02 and Fis = 0·43 ± 0·06). Significant genetic differentiation between populations was detected (Fst = 0·39 ± 0·07). Average gene flow between pairs of populations was relatively low and had high variation (Nm = 0·46 ± 0·21), which denotes a pattern of isolation by distance. The genetic structure of populations of T. achyrostachys suggests that habitat fragmentation has reduced allelic richness and genetic diversity, and increased significant genetic differentiation (by approx. 40 %) between populations. Conclusions The F-statistic values (>0) and the level of gene flow found suggest that habitat fragmentation has broken up the former population structure. In this context, it is proposed that the host trees of T. achyrostachys should be considered as a conservation priority, since they represent the limiting factor to bromeliad population growth and connectivity.
Revised on June 15, 2004
Accepted on June 18, 2004
Diversity and Genetic Structure of the Mexican Endemic Epiphyte Tillandsia achyrostachys E. Morr. ex Baker var. achyrostachys (Bromeliaceae)
JORGE GONZÁLEZ-ASTORGA1*,
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
T. Barbara, G. Martinelli, C. Palma-Silva, M. F. Fay, S. Mayo, and C. Lexer Genetic relationships and variation in reproductive strategies in four closely related bromeliads adapted to neotropical 'inselbergs': Alcantarea glaziouana, A. regina, A. geniculata and A. imperialis (Bromeliaceae) Ann. Bot., January 1, 2009; 103(1): 65 - 77. [Abstract] [Full Text] [PDF] |
||||
![]() |
I. Avila-Diaz and K. Oyama Conservation genetics of an endemic and endangered epiphytic Laelia speciosa (Orchidaceae) Am. J. Botany, February 1, 2007; 94(2): 184 - 193. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. ALCANTARA, J. SEMIR, and V. N. SOLFERINI Low Genetic Structure in an Epiphytic Orchidaceae (Oncidium hookeri) in the Atlantic Rainforest of South-eastern Brazil Ann. Bot., December 1, 2006; 98(6): 1207 - 1213. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. GONZALEZ-ASTORGA, A. P. VOVIDES, A. CRUZ-ANGON, P. OCTAVIO-AGUILAR, and C. IGLESIAS Allozyme Variation in the Three Extant Populations of the Narrowly Endemic Cycad Dioon angustifolium Miq. (Zamiaceae) from North-eastern Mexico Ann. Bot., May 1, 2005; 95(6): 999 - 1007. [Abstract] [Full Text] [PDF] |
||||

