Recolonization after habitat restoration leads to decreased genetic variation in populations of a terrestrial orchid

Abstract

Colonization is crucial to habitat restoration projects that rely on the spontaneous regeneration of the original vegetation. However, as a previously declining plant species spreads again, the likelihood of founder effects increases through recurrent population founding and associated serial bottlenecks. We related Amplified Fragment Length Polymorphism markers genetic variation and fitness to colonization history for all extant populations of the outcrossing terrestrial orchid Dactylorhiza incarnata in an isolated coastal dune complex. Around 1970, D. incarnata suffered a severe bottleneck yet ultimately persisted and gradually spread throughout the spatially segregated dune slacks, aided by the restoration of an open vegetation. Genetic assignment demonstrated dispersal to vacant sites from few nearby extant populations and very limited inflow from outside the spatially isolated reserve. Results further indicated that recurrent founding from few local sources resulted in the loss of genetic diversity and promoted genetic divergence (F(ST) = 0.35) among populations, but did not influence population fitness. The few source populations initially available and the limited inflow of genes from outside the study reserve, as a consequence of habitat degradation and spatial isolation, may have magnified the genetic effects of recurrent population founding.

Rapid Buildup of Genetic Diversity in Founder Populations of the Gynodioecious Plant Species Origanum vulgare after Semi-Natural Grassland Restoration

“…So far, there are only few reports on the genetic effects of spontaneous plant colonization directly following ecological restoration practices, e.g. [7]–[9].…”

Seed dispersal in six species of terrestrial orchids in Biebrza National Park (NE Poland)

“…Data from field observations testing seed dispersal is very scarce, and mostly focused on seeds dispersed by animals, mainly in fleshy-fruited plants [21][22][23][24][25]. Genetic methods, based both on parentage analysis, fine-scale spatial genetic analysis and assignment tests, have also been used to assess the relative contributions of seed dispersal to gene flow [1,10,12,13,[26][27][28][29][30]. We should remember that many genetic studies based on F st (the standardized measure of the genetic variance among populations), although very valuable in explaining gene exchange, do not reflect actual seed dispersal.…”

Genetic diversity of Dactylorhiza incarnata (Orchidaceae) in northern Poland

“…In Pomerania, a similar pattern of differentiation was also observed, with G ST = 0.55 [19]. A slightly lower value of genetic differentiation, but still high, was reported by Vandepitte et al [55] within populations along the Belgian-French coast (F ST = 0.35), using the AFLP markers. In turn, in our study the genetic differentiation of the early marsh orchid populations was low (F ST = 0.149 and R ST = 0.174).…”