Implications of seed germination ecology for conservation of Camptotheca acuminata , a rare, endemic, and endangered spe
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Implications of seed germination ecology for conservation of Camptotheca acuminata, a rare, endemic, and endangered species in China Bin Wen
. Peiru Yang
Received: 23 September 2020 / Accepted: 3 November 2020 Ó Springer Nature B.V. 2020
Abstract Seed germination and seedling recruitment are among the most critical stages for plant population persistence and development, which may be influenced by habitat fragmentation and resulting microhabitat changes. We conducted laboratory and field experiments using seeds of Camptotheca acuminata, a rare, endemic, and endangered species in China, to investigate the effects of temperature change and water availability on seed viability and germination. The seeds were sensitive to high temperature and water stress. Germination percentages [ 60% occurred only between 20–35 °C and water potentials [ - 0.6 MPa. Heating at 75 °C and above for 30 min, continuous heating at 40 °C for 20 days, or desiccation following 120 h imbibition killed nearly all seeds. These seed traits made none of the five microhabitats investigated suitable for regeneration. In the understory plot, most seeds germinated, but the
resultant seedlings survived only a short time, depending on reserve food supply from the seeds. Sensitivity to high temperature and water stress inhibited germination in the other plots and most seeds died in the hydration-dehydration cycles. We concluded that efficient natural regeneration could occur only in very special habitats: cool, with stable moist soil but ample sunlight, most likely in suitable gaps in continuous forests. In addition to habitat loss and over-exploitation, difficulties in natural seed germination and seedling recruitment are primary reasons for the current status of C. acuminata. For population recovery of C. acuminata, understory microhabitat protection and artificial support for germination and seedling recruitment are required. Keywords Habitat fragmentation Hightemperature tolerance Medicinal tree Plant diversity conservation Water stress
Communicated by Thomas Abeli. B. Wen (&) P. Yang CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, Yunnan, China e-mail: [email protected] B. Wen Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Mengla 666303, Yunnan, China
Introduction Habitat fragmentation is a widespread phenomenon across terrestrial ecosystems (Ashworth and Martı´ 2011). On habitat fragmentation, some conclusions can be drawn based on cumulated evidences: (1) it causes diverse biotic and abiotic changes, which are generally reported as the so-called edge effects and
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dry-hot effects, including temperature increase and moisture decrease in forest remnants (Gascon et al. 2000; Ma et al. 1998); (2) fragmentation may affect biological and ecological processes of plants at many stages of their life cycle, from reproductive to vegetative gro
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