Influence of niche similarity on hybridization betweenMyriophyllum sibiricumandM. spicatum

Abstract

The impact of ecological factors on natural hybridization is of widespread interest. Here, we asked whether climate niche influences hybridization between the two closely related plant species Myriophyllum sibiricum and M. spicatum. Eight microsatellite loci and two chloroplast fragments were used to investigate the occurrence of hybridization between these two species in two co-occurring regions: north-east China (NEC) and the QinghaiTibetan Plateau (QTP). The climate niches of the species were quantified by principal component analysis with bioclimatic data, and niche comparisons were performed between the two species in each region. Reciprocal hybridization was observed, and M. sibiricum was favoured as the maternal species. Furthermore, hybrids were rare in NEC but common in the QTP. Accordingly, in NEC, the two species were climatically distinct, and hybrids only occurred in the narrow geographical or ecological transition zone, whereas in the QTP, obvious niche overlaps were found for the two species, and hybrids occurred in multiple contact zones. This association between hybridization pattern and climate niche similarity suggests that the level of hybridization was promoted by niche overlap. Compared with the parental species, similar climate niches were found for the hybrid populations in the QTP, indicating that other environmental factors rather than climate were important for hybrid persistence. Our findings highlight the significance of climate niche with respect to hybridization patterns in plants.

Influence of geography and environment on patterns of genetic differentiation in a widespread submerged macrophyte, Eurasian watermilfoil (Myriophyllum spicatum L., Haloragaceae)

“…In our previous study, we confirmed that hybridization between these two species also occurred in China (Wu et al. ). Hybrid populations identified by morphological traits and genetic data were not included in this study.…”

“…A closely related species, M. sibiricum, co-occurs in the QTP region and northeast China (Yu et al 2002), and hybridization between M. spicatum and M. sibiricum has been reported in North America Les 2002, 2007). In our previous study, we confirmed that hybridization between these two species also occurred in China (Wu et al 2015). Hybrid populations identified by morphological traits and genetic data were not included in this study.…”

Factors Influencing the Distribution of Invasive Hybrid (Myriophyllum Spicatum x M. Sibiricum) Watermilfoil and Parental Taxa in Minnesota

“…The types of lakes that hybrid watermilfoil inhabited were very similar to those with Eurasian and northern in regards to our analyzed lake attributes; lake attributes do not appear to determine differential persistence of hybrids. Wu et al [39] quantified and compared the climate niches of Eurasian and northern watermilfoil in two co-occurring regions in their native range. They determined that hybrid watermilfoil was more commonly found in the region where Eurasian and northern watermilfoil occupied similar environments, because of the increased likelihood of contact between the two taxa [39].…”

“…Wu et al [39] quantified and compared the climate niches of Eurasian and northern watermilfoil in two co-occurring regions in their native range. They determined that hybrid watermilfoil was more commonly found in the region where Eurasian and northern watermilfoil occupied similar environments, because of the increased likelihood of contact between the two taxa [39]. Hybridization was less likely to occur where Eurasian and northern watermilfoil occupied areas unique to their respective niche.…”

Environmental (in)dependence of a hybrid zone: Insights from molecular markers and ecological niche modeling in a hybrid zone ofOriganum(Lamiaceae) on the island of Crete

“…Over the last years, various GIS‐based methods using the distribution profiles of the parental and hybrid taxa succeeded in identifying hybrid zones where environmental selection acts upon their observed spatial patterns (Cullingham et al., ; Ortego et al., ; Wu, Ding, Yu, & Xu, ). Additionally, Swenson (, ) pointed out the utility of ENMs in testing classic theories concerning environment‐dependent (bounded hybrid superiority) or environment‐independent types (tension zone) of hybrid zones, and up to now, this type of modeling has been applied in various hybrid zone systems (e.g., Australian crickets, Kohlmann, Nix, & Shaw, ; North American avian, Cicero, ; Swenson, ; passerines in Europe, Engler, Rödder, Elle, Hochkirch, & Secondi, ).…”