Conservation genetics of an endemic and endangered epiphyticLaelia speciosa(Orchidaceae)

Abstract

We used isozymes (16 loci in 11 enzymatic systems) from Laelia speciosa, an endemic and endangered epiphytic orchid of Mexico, to assess the genetic diversity and population genetic structure in nine populations distributed along its geographic range, as well as to detect those populations that are genetically unique and therefore deserve high-priority protection. On average, the genetic diversity was high (percentage of polymorphic loci, P(p) = 76%, mean number of alleles per locus, A = 3.34, the average observed heterozygosity H(O) = 0.302, the average expected heterozygosity H(E) = 0.382). Moderate levels of inbreeding ( f = 0.216, 95% confidence interval = 0.029-0.381) were found. Low levels of genetic differentiation were observed among populations ((p) = 0.040); however, there was a significant correlation between geographic and genetic distances among the populations (Mantel test: r(2) = 0.43, P < 0.05). Populations located within the same mountain range were genetically more similar. Private alleles were found, so proper management requires protection and maintenance of genetic diversity throughout its range. In case of reintroduction, we suggest using individuals propagated from seeds from as many capsules as possible, from close populations. An ex situ conservation strategy also is proposed.

Genetic differentiation and diversity of Adansonia digitata L (baobab) in Malawi using microsatellite markers

“…Over time, baobab demography has been influenced substantially by anthropogenic factors (land -use pattern, trampling by domesticated livestock), climate (prolonged drought), elephant damage (Edkins et al 2007;Wilson 1988), fire, clearing during cultivation, browsing (Chirwa et al 2006) which have had adverse impact on genetic diversity. It is known that positive correlation exists among the levels of genetic diversity and fitness in plants ( A´vila-di´az and Oyama 2007). For baobab domestication to succeed, it requires understanding of the genetic diversity since it is the fabric of evolution, the base material on which adaptation depends with high levels of genetic diversity considered as acceptable for conferring the ability to respond to threats such as diseases, parasites, predators and environmental change (Amos and Harwood 1998).…”

High gene flow in epiphytic ferns despite habitat loss and fragmentation

“…In determining the genetic effects of fragmentation, plant longevity, mating system and ability for dispersal play an important role (Hamrick and Godt 1996). Similar to tropical trees (Nason 2002), epiphytes seem to be more resistant to adverse genetic consequences of habitat fragmentation (e.g., Alcantara et al 2006; Avila-Diaz and Oyama 2007; Murren 2003; but see González-Astorga et al 2004) than terrestrial herbs. Most epiphytes are wind-dispersed (Benzing 1990), and especially epiphytic ferns and orchids with their dust-like diaspores can bridge even long distances between remnant forest patches, which efficiently reduces genetic isolation.…”

“…In recently fragmented populations often no effects on population genetic structure were found (reviewed in Aguilar et al 2008; González-Astorga and Núñez-Farfán 2001; Murren 2003; Neel and Ellstrand 2001). Long-lived species and/or species with far-ranging pollination or seed dispersal syndromes like neotropical tree species (reviewed in Nason 2002) and epiphytic orchids (Ackerman and Ward 1999; Avila-Diaz and Oyama 2007; Bush et al 1999; Trapnell and Hamrick 2004; Trapnell et al 2004) exhibit high levels of genetic diversity and low genetic differentiation among populations even when they are separated by long distances.…”

Molecular evidence reveals fungi associated within the epiphytic orchid Laelia speciosa (HBK) Schltr.

“…However, thousands of plants are harvested every year from their habitats to be sold due to the beauty of their fl owers. This massive harvesting has caused local extinction, but fortunately, large populations can still be found (Halbinger and Soto, 1997;Ávila-Díaz and Oyama, 2007). Samples were collected in the Olvido population (19° 37'N, 101° 29' W, 2,361 m), and in Indaparapeo (19° 43' N, 101° 55' W, 2,400 m).…”