Successful translocation of the threatened New Zealand root-holoparasite Dactylanthus taylorii (Mystropetalaceae)

Abstract

The conservation and translocation of threatened holoparasitic flowering plants provide added challenges due to their complete host dependency and often large knowledge gaps of their autecology. Here, we present the first successful, quantified field trial to establish from seed populations of dactylanthus (Dactylanthus taylorii, Mystropetalaceae), a threatened New Zealand endemic rootholoparasitic angiosperm. Establishment was monitored at four sites at Waipapa, Pureora Forest Park. The impact of two different sowing methods (broad-and central-sown), canopy state (as a proxy for soil moisture levels) and three dominant host species were tested. Establishment of dactylanthus was confirmed in 22 out of 24 plots 10 years after sowing, with earliest emergence after 4 years. Average and maximum inflorescence numbers per plot were similar to those of protected wild populations. The only opencanopy site performed worse in comparison with a closed-canopy site sharing the same dominant host species; differences in root availability and survival of the desiccation-sensitive seeds were regarded as the most likely explanations. Host species dominance had a significant impact on inflorescence numbers, indicating host preference in the species despite a wide host range. In contrast to longer-established wild populations, most of which are male-biased, female inflorescences strongly outnumbered males, considered as evidence of environmental sex determination and sex-switching of individuals. Findings from this study have increased our knowledge of the biology of dactylanthus, confirmed translocation as an effective tool in the conservation of the species and should be applicable for the protection of threatened parasitic plants species elsewhere in the world.

Langsdorffia: Creatures from the deep?

“…Future work should focus on the effective propagation of Langsdorffia. The translocation and conservation of holoparasitic flowering plants are impeded significantly by the complete dependency on their host plants (Holzapfel, Dodgson, & Rohan, 2018). As a consequence of their difficulty of cultivation, parasitic plants seem to be underrepresented significantly in conservation collections.…”

Best practices, errors, and perspectives of half a century of plant translocation in Italy

“…Conservation translocations (translocation hereafter) are intentional movements of plant and animal individuals for conservation purposes, including population reinforcement (augmentation of an existing population), reintroduction (release of an organism in a site from which it has disappeared), and conservation introduction (release of an organisms outside its natural range) (IUCN, 2013). Although translocations remain high‐risk and high‐cost conservation practices (Fenu et al., 2016), their importance in conservation science is increasing worldwide, as demonstrated by successful projects (Colas et al., 2008; Draper Munt et al., 2016; Holzapfel et al., 2016; Maunder et al., 2000; Soorae, 2021).…”

Center for Plant Conservation's Best Practice Guidelines for the reintroduction of rare plants

“…Reintroduction plans should also account for a species life-history in the experimental design and when setting success benchmarks. For example, reintroductions of the root-holoparasite, Dactylanthus taylorii , to four sites in New Zealand revealed that sowing method, canopy type, and the dominant host influenced establishment and flowering ( Holzapfel et al., 2016 ). Because flowering maturation required four years, different conclusions could have been drawn if the reintroduction had not been tracked for a decade and accounted for this species' growth rates.…”