Early genetic consequences of defaunation in a large-seeded vertebrate-dispersed palm (Syagrus romanzoffiana)

GIOMBINI, M. I.; TOSTO, D. S.; SICA, Y. V.; SICA, Y. V.; BRAVO, S. P.; BRAVO, S. P.; GIOMBINI, M. I.; TOSTO, D. S.

HEREDITY

NATURE PUBLISHING GROUP

Lugar: Londres; Año: 2017 vol. 118 p. 568 - 577

0018-067X

Plant populations are seriously threatened byanthropogenic habitat disturbance. In particular, defaunation may disruptplant-disperser mutualisms, thus reducing levels of seed-mediated gene flow andgenetic variation in animal-dispersed plants. This may ultimately limit theiradaptive potential and ability to cope with environmental change. Tropicalforest remnants are typically deprived of medium to large vertebrates uponwhich many large-seeded plants rely for accomplishing effective seed dispersal.Our main goal was to examine the potential early genetic consequences of theloss of large vertebrates for large-seeded vertebrate-dispersed plants. Wecompared the genetic variation in early-stage individuals of the large-seededpalm Syagrus romanzoffiana betweencontinuous protected forest and nearby partially defaunated fragments in theAtlantic Forest of South America. Using nine microsatellites, we found lowerallelic richness and stronger fine-scale spatial genetic structure in thedisturbed area. In addition, the percentage of dispersed recruits aroundconspecific adults was lower, although not significantly, in the disturbed area(median values: 0.0% vs. 14.4%). On the other hand, no evidence of increasedinbreeding or reduced pollen-mediated gene flow (selfing rate and diversity ofpollen donors) was found in the disturbed area. Our findings are stronglysuggestive of some early genetic consequences resulting from the limitation incontemporary gene flow via seeds, but not pollen, in defaunated areas.Plant-disperser mutualisms involving medium-large frugivores, which areseriously threatened in tropical systems, should therefore be protected towarrant the maintenance of seed-mediated gene flow and genetic diversity inlarge-seeded plants.