Ex situ conservation
Exceptional Species
Exceptional species refers to plant species with challenges in their ex situ (“off site”) conservation. This includes both physiological responses that prevent ex situ storage methods, as well as other challenges throughout the conservation pipeline, such as access.
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The challenges are coined as exceptional factors. Members of the Hawaiʻi Seed Bank Partnership (HSBP) collaborated to apply 4 exceptional factors to the native Hawaiian flora to support conservation partners in Hawai’i and to drive research to investigate the remaining gaps.
Exceptionality factor 1 (EF1) is that seeds are not produced or are extremely limited in quantity, viability, or accessibility.
Exceptionality factor 2 (EF2) states that seeds cannot survive drying to ca. 15% RH.
Exceptionality factor 3 (EF3) is seeds may be desiccation tolerant, but their viability will decline to 50% (p50) in <20 years.
Exceptionality factor 4 (EF4) states that seeds are deeply dormant with very long germination times (>1 year), and germination has not yet been successful with any conventional dormancy‐breaking method (Pence et al., 2022a).
Multiple exceptionality factors includes species that fit more than one EF.
Identifying exceptional factors and species for the Hawaiian flora is a valuable tool to aid the conservation community for ex situ collections and management. While seed storage is the most efficient way to preserve most of the Hawaiian flora (Weisenberger and Keir, 2014), other collections may be necessary to overcome exceptional factors.
This work continues to build upon 2019 Hawai’i Seed Bank Userʻs Guide, which advanced our understanding of ex situ storage and exceptional factors affecting the Hawaiian flora. Due to the highly endangered flora and remaining knowledge gaps in ex situ storage behavior, it is important to identify which species are known, unknown, and inferred to inform conservation and restoration activities. Here, we reassess the Hawaiian flora’s ex situ storage behavior by applying exceptional factors based on research and data from conservation collections. This work will need to be periodically updated as the conservation community gathers new data and research.
For conservation practitioners, we recommend a cautious approach due to the high number of endangered species and limited plant material, and to drive research.
The exceptional factors information presented here can further inform and empower practitioners to collect and manage new species and increase the genetic diversity of species within collections. Regional assessments, such as this, help unify and strengthen conservation and brings Hawaiʻi closer to meeting the challenges of conserving its unique flora.
Seeds of Hawai’i also reflects this updated information.
[Will update]
Photo credits:
Contributing Network members: Center for Plant Conservation, Lyon Arboretum, O‘ahu Army Natural Resources Program, National Tropical Botanical Garden, US Fish & Wildlife Service, State of Hawai‘i Department of Land & Natural Resources – Division of Forestry & Wildlife, and Plant Extinction Prevention Program of Hawai‘i.
Laukahi has a growing number of partners that help to implement the Hawai‘i Strategy for Plant Conservation by supporting our initiatives, conducting field work to protect native habitats, propagate and secure propagules in ex situ facilities, and do research to inform strategies.
Mahalo to all our partners!