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

Jasmine A Eltawely,Raymond M Newman,Ryan A Thum

doi:10.3390/d12030120

Jasmine A Eltawely, Raymond M Newman + Show 1 more

Open Access

https://doi.org/10.3390/d12030120

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Abstract

Eurasian watermilfoil (Myriophyllum spicatum L.) hybridizes with the native northern watermilfoil (M. sibiricum Kom.), which raises new issues regarding management strategies to control infestations. To determine the distribution of hybrid (and coincidentally Eurasian and northern) watermilfoil in Minnesota, we sampled lakes across the state during 2017–2018 for watermilfoil. A total of 62 lakes were sampled, spanning a range of sizes and duration of invasion. Forty-three lakes contained Eurasian, 28 contained hybrid and 21 contained northern watermilfoil. Eurasian watermilfoil populations were widespread throughout the state. Hybrid populations were more commonly found in lakes in the seven county Twin Cities Metro and northern watermilfoil populations were more commonly found in lakes outside of the Metro area. We found no evidence that hybrid watermilfoil occurred in lakes environmentally different than those with Eurasian and northern watermilfoil, suggesting that hybrid watermilfoil is not associated with a unique niche. Hybrid watermilfoil presence was significantly associated with the Metro area, which may likely be due to spatial and temporal factors associated with hybrid formation and spread. Hybrid watermilfoil presence was also significantly associated with lakes that had more parking spaces and older infestations, but this relationship was not significant when the effect of region was considered. Hybrid watermilfoil populations were the result of both in situ hybridization and clonal spread and continued assessment is needed to determine if particularly invasive or herbicide-resistant genotypes develop.

Highlights

Hybrid watermilfoil was most commonly found in lakes in the Metro area (82%)
This contrasts with Eurasian watermilfoil infestations, which we found to be due to clonal spread and persistence
Eurasian watermilfoil infestations were primarily the result of clonal spread, whereas there was no evidence of clonal spread in native northern watermilfoil populations, which were more genetically diverse

Summary

Introduction

There is an increasing appreciation for the role of genetics and hybridization in invasion biology [1,2,3,4,5].Hybridization between introduced and native species can lead to novel combinations of traits, novel trait values, or increased genetic variation, which may result in superior competitive phenotypes [2,3,6].Hybrid species may have increased likelihood of survival and establishment success in novel habitats. most research on invasive hybrids has focused on terrestrial and wetland herbaceous plants [5,7], hybrids have been associated with invasiveness in woody plants [8], submersed aquatic plants [3,9] and animals [10]. There is an increasing appreciation for the role of genetics and hybridization in invasion biology [1,2,3,4,5]. Hybridization between introduced and native species can lead to novel combinations of traits, novel trait values, or increased genetic variation, which may result in superior competitive phenotypes [2,3,6]. Identifying hybrids and the factors associated with their occurrence and spread is important to understanding biological invasions and informing management of invasive species. Eurasian watermilfoil (Myriophyllum spicatum L.) is one of the most heavily managed invasive aquatic plants in North America. Eurasian watermilfoil was first documented in Diversity 2020, 12, 120; doi:10.3390/d12030120 www.mdpi.com/journal/diversity

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