Enhancing Conservation of a Globally Imperiled Rockland Herb (Linum arenicola) through Assessments of Seed Functional Traits and Multi-Dimensional Germination Niche Breadths.

Héctor Eduardo Pérez,Luis Andres Ochoa Chumana

doi:10.3390/plants9111493

Abstract

Humans currently face an extraordinary period of plant biodiversity loss. One strategy to stem further losses involves the development of species-level recovery plans that guide conservation actions. Seeds represent an important component in the life history of plants and are crucial for conservation activities. Yet, most recovery plans contain meager seed biology information. We set out to examine seed functional traits and germination niche breadth of Linum arenicola seeds exposed to a range of thermal, photoperiodic, and salinity gradients to gain perspectives on the seed biology of this endangered species that may inform conservation decision making and assist recovery plan development. We found that fresh seeds possess non-deep physiological dormancy, which may be alleviated via a four-week dry after-ripening treatment. The germination response of non-dormant seeds is subsequently promoted by constant rather than alternating temperatures. The optimum germination temperature range is 20–22 °C. Non-dormant seeds do not possess an absolute light requirement for germination, but are sensitive to low levels of salinity (EC50 = 6.34 ppth NaCl). The narrow thermal and salinity germination niche breadths reported here suggest a specialized reproductive strategy that may require careful consideration when planning ex and in situ conservation activities.

Highlights

Species extinctions measured on geologic time scales are a normal part of the evolutionary process.Pimm et al [1] estimate that the background extinction rate due to naturally occurring environmental and ecological factors is about 0.1 extinctions per million species years (E/MSY)
This stands in stark contrast to the estimated 1000-fold increase in current extinction rates induced by human activity
We examined seed functional traits and germination niche breadth of Linum arenicola seeds exposed to a range of thermal, photoperiodic, and salinity gradients to gain perspectives on the seed biology of this endangered species that may inform conservation decision making and assist recovery plan development

Summary

Introduction

Pimm et al [1] estimate that the background extinction rate due to naturally occurring environmental and ecological factors is about 0.1 extinctions per million species years (E/MSY). This stands in stark contrast to the estimated 1000-fold increase in current extinction rates induced by human activity. Current estimates suggest that almost 33 to 40% of all plant species are threatened with extinction [2,3]. Such information is startling considering that humans depend on plants for life and points to an unprecedented time of plant biodiversity loss

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