Disrupted connectivity within a metapopulation of a wind-pollinated declining conifer, Taxus baccata L.  

作　　者：Igor J.Chybicki Juan J.Robledo-Arnuncio Jan Bodziarczyk Marcin Widlak Katarzyna Meyza Andrzej Oleksa Bartosz Ulaszewski 

机构地区：[1]Department of Genetics,Kazimierz Wielki University,Chodkiewicza 30,85064,Bydgoszcz,Poland [2]Institute of Forest Sciences,ICIFOR-INIA,CSIC,Ctra.de la Coruna km 7.5,28040,Madrid,Spain [3]Department of Forest Biodiversity,University of Agriculture in Krakow,29-listopada 46,31-425,Krakow,Poland [4]Gorlice Forest District,Zagorzany 343,38-333,Zagorzany,Poland

出　　处：《Forest Ecosystems》2024年第6期861-874,共14页森林生态系统(英文版)

基　　金：supported by the National Science Centre,Poland(the grant UMO-2018/31/B/NZ8/01808 to IJC).

摘　　要：Population connectivity through seed and pollen dispersal determines the genetic diversity,adaptive potential,and demography of plant metapopulations.In wind-pollinated trees,population connectivity is typically maintained by long-distance pollen flow,counteracting the genetic differentiation generated by drift and restricted seed dispersal.Although strong population fragmentation is theoretically expected to disrupt connectivity in forest trees,empirical evidence remains scarce and inconclusive.We investigated contemporary connectivity within a network of small remnant populations of a declining conifer(Taxus baccata L.),which have been hypothesized to be largely isolated from each other.We tested this hypothesis using molecular data for adult trees and naturally recruited seedlings from all known remnants across a fragmented landscape spanning a length of 20 km,and a specifically designed statistical approach to quantify contemporary pollen and seed migration rates between populations.We additionally assessed dispersal potential using a spatially explicit parentage analysis to estimate seed and pollen dispersal kernels within one of the remnants.Estimated pairwise migration rates between populations were barely detectable for seeds,while they were larger(up to 1.1%)and significant for pollen.Both seed and pollen migration rates decreased with geographic distance between populations,more steeply in the case of pollen migration.According to parentage-based dispersal kernels,51.8% of seeds and 11.4% of pollen travel less than 25 m,whereas 0.2% of seeds and 36.1%of pollen travel more than 250 m from a source tree.In addition,1.2% of pollen can travel more than 2.5 km.We showed that strong present-day population fragmentation,with separation distances over a few kilometers between small fragments,can substantially limit the connectivity of a wind-pollinated declining tree,leading to low pollen-mediated contemporary gene flow and null or virtually null demographic connectivity via seed dispersal.

关 键 词：Population connectivity FRAGMENTATION Seed dispersal Pollen dispersal Gene flow Genetic assignment PARENTAGE European yew 

分 类 号：Q94[生物学—植物学]