Extensive pollen flow in a natural fragmented population of Patagonian cypress Austrocedrus chilensis

Abstract

Habitat fragmentation might significantly affect mating and pollen dispersal patterns in plant populations, contributing to the decline of remnant populations. However, wind-pollinated species are able to disperse pollen at longer distances after opening of the canopy. Our objectives were to characterize the mating system parameters and to estimate the average distance of effective pollen dispersal in the windpollinated conifer Austrocedrus chilensis. We sampled 19 "mother trees," 200 progeny, and 81 additional adults (both male and female), in a fragmented population at the Argentinean Patagonian steppe. We registered the spatial positions of individuals and genotyped all samples with five microsatellite markers. We found a high genetic diversity, a moderated rate of biparental inbreeding (t m −t s =0.105), and a complete absence of correlated paternity (r p =−0.015). The effective number of pollen donors contributing to a single mother (N ep ) was 13.9. Applying TWOGENER, we estimated a low but significant differentiation among the inferred pollen pools (Φ FT =0.036, p=0.001) and a very large average pollen dispersal distance (d=1,032.3 m). The leptokurtic distribution (b=0.18) presumes a potential for even larger dispersal distances. The high genetic diversity, the mating patterns, and the extensive pollen dispersal presume that habitat fragmentation did not have a negative impact on pollen movement in this population of A. chilensis. Genetic connectivity among fragmented populations scattered in the Patagonian region is possible, and we stress the need of management policies at the landscape level.

Genetic Characterization of Chinese fir from Six Provinces in Southern China and Construction of a Core Collection

“… 32 . The mean values for Ho and He obtained using SSR markers in this germplasm were higher than those reported for other Chinese firs 24 – 26 and other conifers 33 – 35 , but lower than those in Abies chensiensis and Austrocedrus chilensis 36 , 37 ; this suggests that the level of genetic diversity in this germplasm is moderate. Outcrossing and wind-pollination may explain the considerable level of polymorphisms in this species 38 – 41 .…”

Genetic characterization of red-colored heartwood genotypes of Chinese fir using simple sequence repeat (SSR) markers

“…H E (0.584) obtained using SSR markers was also higher for some conifers, including Pinus bungeana (H E : 0.249; Zhao et al, 2014), Pinus massoniana (H E : 0.536; Bai et al, 2014), and Pinus dabeshanensis (H E : 0.458; Xiang et al, 2015). However, it is lower than that of Abies chensiensis (H E : 0.803; Li et al, 2012), and Austrocedrus chilensis (H E : 0.865; Colabella et al, 2014). Further studies have indicated that the genetic diversity of this germplasm resource is moderate.…”

Habitat fragmentation influences genetic diversity and differentiation: Fine‐scale population structure ofCercis canadensis(eastern redbud)

“…Limited gene flow typically leads to reduced genetic diversity, increased population structure, and inbreeding within populations (Byrne et al, 2008; Sherwin & Moritz, 2000; Young et al, 1996), which were not consistent with our findings. Other studies focused on forest trees in fragmented landscapes found that regardless of moderate‐to‐high habitat fragmentation, many insect‐pollinated tree species were able to maintain high levels of gene flow across isolated patches through increased long distance pollen dispersal (Bacles, Burczyk, Lowe, & Ennos, 2005; Colabella, Gallo, Moreno, & Marchelli, 2014; Nason & Hamrick, 1997; Wang, Stephen, & Xiao‐Yong, 2011). Our study findings are consistent with these studies as shown by the high level of gene flow present across fragmented C. canadensis populations.…”