Thermal Requirements Underpinning Germination Allude to Risk of Species Decline from Climate Warming

Abstract

The storage of seeds is a commonly used means of preserving plant genetic diversity in the face of rising threats such as climate change. Here, the findings of research from the past decade into thermal requirements for germination are synthesised for more than 100 plant species from southern Western Australia. This global biodiversity hotspot is predicted to suffer major plant collapse under forecast climate change. A temperature gradient plate was used to assess the thermal requirements underpinning seed germination in both commonly occurring and geographically restricted species. The results suggest that the local climate of the seed source sites does not drive seed responses, neither is it indicative of temperatures for optimal germination. The low diurnal phase of the temperature regime provided the most significant impact on germination timing. Several species germinated optimally at mean temperatures below or close to current wet quarter temperatures, and more than 40% of species were likely to be impacted in the future, with germination occurring under supra-optimal temperature conditions. This research highlights both species vulnerability and resilience to a warming climate during the regeneration phase of the life cycle and provides vital information for those aiming to manage, conserve and restore this regional flora.

Simulated Photovoltaic Solar Panels Alter the Seed Bank Survival of Two Desert Annual Plant Species

“…Studies of seed bank trait-environment interactions are needed to understand responses to anthropogenic disturbances and predict demographic and ecological consequences of such changes into the future, including changes in growth rates and extinction [ 7 , 19 , 20 , 21 ]. Deserts provide an ideal setting for experimentation given that relatively small variation in amounts of rainfall can elicit dramatic effects on the density and life history traits of desert annuals, including seed emergence and seed survival [ 57 , 58 ].…”

“…Understanding seed banks has proven to be exceptionally challenging, rendering our knowledge of early life history traits incomplete across the plant kingdom [ 1 , 2 ]. Studies are needed to enumerate and predict changes in seed banks, particularly to ascertain if plant species’ or communities’ seed banks respond to environmental changes [ 2 , 3 , 4 , 5 , 6 , 7 , 8 ]. Studies of annual seed banks in deserts may be especially useful to study seed bank trait–environment interactions because these environments are characterized by extreme variability in temperature and precipitation [ 9 , 10 ]—variability that increasingly characterizes Earth’s environments.…”

Simulated Photovoltaic Solar Panels Alters the Seed Bank Survival of Desert Annual Plant Species

“…interactions are needed to understand responses to anthropogenic changes and predict demographic and ecological consequences of such changes into the future, including changes in growth rates and extinction [7,[11][12][13]. Deserts provide an ideal setting for experimentation given that relatively small variation in amounts of rainfall can elicit dramatic effects on the density and life history traits of desert annuals, including seed emergence and seed survival [54,55].…”

“…Understanding seed banks has proven to be exceptionally challenging, rendering our knowledge of early life history traits incomplete across the plant kingdom [1,2]. Studies are needed to enumerate and predict changes in seed banks, particularly to ascertain if plant species' or communities' seed banks respond to environmental changes [2][3][4][5][6][7][8]. Studies of annual seed banks in deserts may be especially useful to study seed bank trait-environment interactions because these environments are characterized by extreme variability in temperature and precipitation [9,10]variability that increasingly characterizes Earth's environments.…”

Differential Interpretation of Mountain Temperatures by Endospermic Seeds of Three Endemic Species Impacts the Timing of In Situ Germination

“…These conditions impact the timing of plant emergence, since dry summer conditions limit water availability and thus seed germination and growth, while cool winter temperatures can limit germination, even when the season has high water availability [ 2 , 3 , 4 ]. In seasonal climates and in moist soils, temperature is usually the main environmental factor influencing seed germination [ 5 ], which is a complex adaptive trait that determines plant establishment and contributes to population persistence [ 6 ]. Moreover, this adaptive trait becomes even more complex in species that produce dormant seeds, by which germination is prevented before or during unfavourable environmental conditions for emergence and subsequent seedling development [ 7 ].…”