Experimental translocation of a rare Hawaiian tree reveals disparity between remnant and potential habitat

Biological Conservation
By: , and 

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Abstract

Translocation is implemented worldwide as a conservation strategy for rare and endangered plant species, yet the factors that influence long-term success remain poorly understood. Remnant wild populations are often used as indicators to model habitat preference and select translocation sites, but such populations may be refugia from past biological or anthropogenic stressors and represent sub-optimal habitat conditions for focal taxa. To test assumptions about habitat preferences of rare species, we conducted a four-year experimental translocation of the Critically Endangered Hawaiian tree, ‘ohe mauka, Polyscias bisattenuata (Araliaceae), planting 3,700 saplings across eleven sites spanning diverse environmental conditions both within and beyond the species’ extant range. We measured seventeen predictor variables at the site and individual plant level in categories of climate, surrounding vegetation, soil chemistry, and genetic provenance. We used linear mixed effects models to assess relative effects of predictors on translocated plant survival, growth, and vigor. The factors which influenced plant performance shifted across ontogeny. The height of surrounding vegetation showed an initial negative relationship with two-year survival, but later showed a positive relationship with four-year growth. Four-year growth demonstrated a strong positive relationship with site annual mean temperature. Successful translocation sites were lower in elevation and warmer in temperature than conditions represented by remnant wild populations. Results demonstrate that basing translocation sites solely on limited extant wild occurrences can lead to suboptimal restoration practices, and experimental outplanting across broad conditions may help identify rare species' contemporary habitat preferences.

Suggested Citation

Douglas, J., Bai, M., Fortini, L., Yelenik, S.G., and Rønsted, N., 2026, Experimental translocation of a rare Hawaiian tree reveals disparity between remnant and potential habitat: Biological Conservation, v. 316, 111686, 14 p., https://doi.org/10.1016/j.biocon.2025.111686.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Experimental translocation of a rare Hawaiian tree reveals disparity between remnant and potential habitat
Series title Biological Conservation
DOI 10.1016/j.biocon.2025.111686
Volume 316
Publication Date February 12, 2026
Year Published 2026
Language English
Publisher Elsevier
Contributing office(s) Pacific Island Ecosystems Research Center
Description 111686, 14 p.
Country United States
State Hawaii
Other Geospatial Kauai
Additional publication details