“Genetic rescue by distant trees in threatened populations of a Mediterranean tree”

Organização: CEF/CEABN

Data: 19 junho :: 12h30 às 13h30

Local: Auditório Florestal do Instituto Superior de Agronomia

Tema: “Genetic rescue by distant trees in threatened populations of a Mediterranean tree”

Orador: António Castilha, Centro de Ecologia Aplicada Prof. Baeta Neves, Instituto Superior de Agronomia

Biosketch: O Dr.Antonio Castilla completou o Doutoramento na Universidade de Sevilha em 2012 tendo tido experiência de pós-Doutoramento na Universidade do Texas e North Arizona. Actualmente é investigador de pós-Doutoramento no Centro de Ecologia Aplicada Prof. Baeta Neves do Instituto Superior de Agronomia, onde investiga quais os mecanismos genéticos que permitem a adaptação das comunidades vegetais às Alterações Globais e como aplicar ferramentas genéticas à conservação da biodiversidade e restauro de ecossistemas.

Abstract: Forest fragmentation represents a major threat to terrestrial biodiversity. Deforestation and resulting declines in tree population density can fundamentally lead to “Allee effects”, potentially compromising survival and reproductive success of tree species. In this line, positive density-dependent reproduction has been reported for a number of tree species with individuals living in dense neighborhoods exhibiting greater fruit and seed production than those more spatially isolated. However, the net effect of positive density-dependence on reproduction is expected to be mediated by the kinship within the conspecific neighborhood. Increased kinship within the immediate neighborhood may lead to intense biparental inbreeding that may result in increased abortion rates. In this study, we tested for positive fine-scale spatial genetic structure (FSGS) in populations of animal-pollinated tree Pyrus bourgeana using microsatellite markers. Also, we conducted hand-pollination experiments using pollen from individuals within and outside of the spatial patches of trees during two consecutive years. Specifically, we investigated the following hypotheses in the Iberian pear: (i) Pyrus bourgeana exhibits significant FSGS with trees within the same patch having increased levels of kinship; and (ii) both fruit and seed production are higher in crosses involving the mating of distant trees. We found positive FSGS in P. bourgaeana populations. Our results also revealed that the mating involving distant parents led to increased fruit production than those involving nearby trees, being the difference greater during the later stages of fruit development. Furthermore, we detected that a substantial portion of saplings in P. bourgaeana populations are clonal shoots instead of recruits from sexual reproduction. Our results support a critical role of pollen quality for the recruitment in tree populations and highlight the relevance of high-mobile pollinators for the preservation of effective pollination services.