Establishing a Wild, Ex Situ Population of a Critically Endangered Shade-Tolerant Rainforest Conifer: A Translocation Experiment

• Published in: PloS one Vol. 11; no. 7; p. e0157559
• Main Authors: Zimmer, Heidi C, Offord, Catherine A, Auld, Tony D, Baker, Patrick J
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 12-07-2016; Public Library of Science (PLoS)
• Subjects: Australia; Biodiversity conservation; Biology and Life Sciences; Coniferophyta - growth & development; Coniferophyta - physiology; Coniferophyta - radiation effects; Conservation of Natural Resources - methods; Ecology; Ecology and Environmental Sciences; Ecosystems; Endangered & extinct species; Endangered Species; Environmental aspects; Extinction; Extinction, Biological; Forests; Light; Morphology; Pinus palustris; Plant Stems - growth & development; Plant Stems - radiation effects; Planting; Population; Population growth; Population number; Rain forests; Rainforest; Rainforests; Risk; Shade; Species extinction; Sunlight; Survival; Threatened species; Translocation; Wollemia nobilis; Australia; Canada; Victoria Australia; United States > US; New South Wales Australia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0157559

Translocation can reduce extinction risk by increasing population size and geographic range, and is increasingly being used in the management of rare and threatened plant species. A critical determinant of successful plant establishment is light environment. Wollemia nobilis (Wollemi pine) is a critically endangered conifer, with a wild population of 83 mature trees and a highly restricted distribution of less than 10 km2. We used under-planting to establish a population of W. nobilis in a new rainforest site. Because its optimal establishment conditions were unknown, we conducted an experimental translocation, planting in a range of different light conditions from deeply shaded to high light gaps. Two years after the experimental translocation, 85% of plants had survived. There were two distinct responses: very high survival (94%) but very low growth, and lower survival (69%) and higher growth, associated with initial plant condition. Overall survival of translocated W. nobilis was strongly increased in planting sites with higher light, in contrast to previous studies demonstrating long-term survival of wild W. nobilis juveniles in deep shade. Translocation by under-planting may be useful in establishing new populations of shade-tolerant plant species, not least by utilizing the range of light conditions that occur in forest understories.