Does genetic diversity of restored sites differ from natural sites? A comparison of Vallisneria americana (Hydrocharitaceae) populations within the Chesapeake Bay

Abstract

The goal of ecological restoration is to re-establish self-sustaining ecosystems that will resist future perturbation without additional human input. We focus here on the re-establishment of submersed aquatic macrophyte beds in the restoration of the Chesapeake Bay estuary. Degraded environmental conditions are often to blame for poor bed establishment, but genetic factors could also be contributing to low survival. We quantified the effect of restoration practices on genetic diversity in the submersed aquatic plant species Vallisneria americana Michx. (Hydrocharitaceae) in the Chesapeake Bay. In 2007, we collected 440 shoots from 8 restored/natural site pairs and 4 restoration stock repositories, and genotyped those individuals at 10 microsatellite loci. Restoration practices do not appear to negatively impact genetic diversity, and basic measures of genetic diversity within restored sites overlap with natural sites. However, small population size of restored sites, significant inbreeding coefficients within 3 sites, and low overlap of allele composition among sites provide cause for concern. These problems are relatively minor, and we propose several corrections that would alleviate them altogether. Managers should be encouraged by our findings as well as the current state of the genetic diversity within V. americana restoration efforts.

Landscape genomics reveals altered genome wide diversity within revegetated stands of Eucalyptus microcarpa (Grey Box)

“…The relatively small difference between revegetation and natural sites highlights the capacity for landscape diversity to be maintained during revegetation, consistent with findings from other studies (Liu et al ., ; Lloyd et al ., ; Reynolds et al ., ; Ritchie & Krauss, ). Careful selection of widely sourced seed, including mixing multiple source populations, can even lead to greater diversity at restored sites than source populations (Smulders et al ., ; Fant et al ., ).…”

Genetic and mating system assessment of translocation success of the long‐lived perennial shrub Lambertia orbifolia (Proteaceae)

“…The Wahlund effect and mode of admixture may also be playing a role in the level of linkage disequilibrium in the Chorkerup translocation, with this phenomenon seen in other translocated populations of plants established using admixture (Fotinos et al 2015; Zavodna et al 2015) and is most likely where admixture occurs multiple times (Pfaff et al 2001). While essentially an artifact of the admixture process, it is important to note that in artificially created populations these effects may be detected during the initial establishment phase but should not necessarily be viewed negatively in terms of long‐term translocation success, as the genetic sub‐ structuring would be expected to dissipate, and the high inbreeding coefficients and linkage disequilibrium decrease as plants from different source populations interbreed (Lloyd et al 2012).…”

Genetic rescue versus outbreeding depression in Vallisneria americana: Implications for mixing seed sources for restoration

“…Reynolds et al (2012b) demonstrated that Zostera marina seeds harvested from multiple parents from nearby beds can preserve genetic diversity in restored sites with no signs of inbreeding depression in either donor or restored sites. Lloyd et al (2012) found that current V. americana restoration techniques generally reflect the genetic diversity found in natural populations in the Chesapeake Bay. We see no strong argument against local sourcing in this case because most populations are not inbred based on microsatellite markers, and population level differences in seed production (Fig.…”

“…Restoration of aquatic species in the Chesapeake Bay typically involves planting locally sourced material, including whole individuals harvested from beds in the same tributary, individuals reared from seeds harvested from nearby beds, or individuals from repositories that were initially established from local populations (Lloyd et al, 2012). Reynolds et al (2012b) demonstrated that Zostera marina seeds harvested from multiple parents from nearby beds can preserve genetic diversity in restored sites with no signs of inbreeding depression in either donor or restored sites.…”