Conservation Genetics of the Endemic Mexican Heliconia uxpanapensis in the Los Tuxtlas Tropical Rain Forest

Abstract

Heliconia uxpanapensis (Heliconiaceae) is an outcrossing endemic herb that grows within continuous and fragmented areas of the tropical rain forest of southeast Veracrúz (México). The genetic diversity, population differentiation, and genetic structure of seven populations of the studied species were assessed using inter-simple sequence repeat) markers. Population differentiation was moderately high (F ST range: 0.18-0.22) and indirect estimates of gene flow were rather low (Nm = 0.65-0.83). Analysis of molecular variance indicated that the populations explained 22.2 percent of the variation, while individuals within the populations accounted for 77.8 percent. The similar and high level of genetic diversity found within populations of the continuous and fragmented forest suggests that H. uxpanapensis has not suffered yet the expected negative effect of fragmentation. Genetic structure analyses indicated the presence of fewer genetic clusters (K = 4) than populations (N = 7). Three of the four fragmented forest populations were assigned each to one of the clusters found within the continuous forest, suggesting the absence of a negative fragmentation effect on the amount and distribution of genetic variation. Given the significant genetic structure combined with high genetic diversity and low levels of gene flow, theoretical simulations indicated that H. uxpanapensis might be highly susceptible to changes in the mating system, which promotes inbreeding within fragmented populations. Thus, future conservation efforts in this species should be directed to ensure that levels of gene flow among populations are sufficient to prevent an increment in the magnitude of inbreeding within fragments.Abstract in Spanish is available at http://www.blackwell-synergy.com/loi/btp.

Life history and past demography maintain genetic structure, outcrossing rate, contemporary pollen gene flow of an understory herb in a highly fragmented rainforest

“…Most genetic variation is contained among individuals within populations (96%) rather than between populations (3%) in fragments of different size. A similar result was obtained for other understory tropical herbs in the same region (Cuartas-Hernández & Núñez-Farfán, 2006; Suárez-Montes, Fornoni & Núñez-Farfán, 2011). Genetic clustering analyses revealed that most populations shared genetic information of one cluster or community, which explain the low genetic differentiation.…”

“…The impact of rainforest fragmentation on the genetic structure of plant populations is highly variable, depending on life history, life-span, and mating system (Cuartas-Hernández & Núñez-Farfán, 2006; Figueroa-Esquivel et al, 2010; Suárez-Montes, Fornoni & Núñez-Farfán, 2011; Chávez-Pesqueira et al, 2014). At the landscape scale, factors like the spatial configuration of fragments can also explain the genetic change of populations (Leimu et al, 2006; Vranckx et al, 2011; Aparicio et al, 2012; Chávez-Pesqueira et al, 2014).…”

Spatial genetic structure in four understoryPsychotriaspecies (Rubiaceae) and implications for tropical forest diversity

“…The program Peakmatcher ( DeHaan et al, 2002 ) was used to generate 0/1 matrices of banding patterns. Bands occurring in fewer than 5% (or more than 95%) of accessions within a species were discarded ( Lynch and Milligan, 1994 ;Suárez-Montes et al, 2011 ;Martínez-Natarén et al, 2014 ). AFLP bands were assumed to correspond to loci with two alleles, in which band presence indicated either a dominant homozygote or a heterozygote, while band absence indicated a recessive homozygote.…”

Peer Review #1 of "Life history and past demography maintain genetic structure, outcrossing rate, contemporary pollen gene flow of an understory herb in a highly fragmented rainforest (v0.1)"

“…The impact of rainforest fragmentation on genetic structure is highly variable between species depending on life history, life-span, and mating system (Cuartas-Hernández & Núñez-Farfán, 2006;Figueroa-Esquivel et al, 2010;Suárez-Montes, Fornoni & Núñez-Farfán, 2011;Chávez-Pesqueira et al, 2014). At the landscape scale, factors like spatial configuration of fragments can also explain the genetic change of populations (Leimu et al, 2006;Vranckx et al, 2011;Aparicio et al, 2012;Chávez-Pesqueira et al, 2014).…”