Restoration Seed Banks-A Matter of Scale
Kings Park and Botanic Garden, West Perth, Western Australia 6005, Australia.Science (Impact Factor: 33.61). 04/2011; 332(6028):424-5. DOI: 10.1126/science.1203083
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- "Although SPAs are widely used in other countries (e.g. for tallgrass prairie communities in the western USA), few examples currently exist in Australia. However, growing demand for seed and the recognition that remnant vegetation is unlikely to provide sufficient seed to meet future restoration targets (Broadhurst et al. 2015; Merritt and Dixon 2011; Mortlock 2000) suggest that SPAs can help meet the supply gap. Two important issues underpin the usefulness of SPAs as sources of high genetic-quality seed, namely inadvertently creating genetic bottlenecks during SPA establishment, and ensuring that the seed produced by a SPA is representative of the diversity present in natural populations. "
ABSTRACT: Vegetation clearing and land-use change have depleted many natural plant communities to the point where restoration is required. A major impediment to the success of rebuilding complex vegetation communities is having regular access to sufficient quantities of high-quality seed. Seed-production areas (SPAs) can help generate this seed, but these must be underpinned by a broad genetic base to maximise the evolutionary potential of restored populations. However, genetic bottlenecks can occur at the collection, establishment and production stages in SPAs, requiring genetic evaluation. This is especially relevant for species that may take many years before a return on SPA investment is realised. Two recently established yellow box (Eucalyptus melliodora A.Cunn. ex Schauer, Myrtaceae) SPAs were evaluated to determine whether genetic bottlenecks had occurred between seed collection and SPA establishment. No evidence was found to suggest that a significant loss of genetic diversity had occurred at this stage, although there was a significant difference in diversity between the two SPAs. Complex population genetic structure was also observed in the seed used to source the SPAs, with up to eight groups identified. Plant survival in the SPAs was influenced by seed collection location but not by SPA location and was not associated with genetic diversity. There were also no associations between genetic diversity and plant growth. These data highlighted the importance of chance events when establishing SPAs and indicated that the two yellow box SPAs are likely to provide genetically diverse seed sources for future restoration projects, especially by pooling seed from both SPAs.
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- "While the use of native species is highly recommended, it often presents major challenges with respect to the availability of seeds as well as the definition of adequate seed harvesting, storage and seeding protocols (Tischew et al. 2011; Oliveira et al. 2011). The successful use of seeds in restoration actions critically depends on the one hand on appropriate storage methods to maintain seed viability, but on the other hand on the knowledge of the conditions that will break seed dormancy (Merritt and Dixon 2011). According to Oliveira et al. (2011), the main drawbacks for predicting germination success in many native species are the knowledge gaps regarding the presence of different types of dormancy and the correspondent dormancy breaking mechanisms. "
ABSTRACT: Context The use of native species in ecological restoration is highly recommended but, in practice, it is often impaired by knowledge gaps in the germination ecology of suitable species. & Aims This study aimed to assess the role of storage condi-tions and seed source on the germination of three Mediterranean shrub species with contrasting types of dormancy. & Methods Ripe fruits were harvested at two or three distant locations in mainland Portugal. Seeds were subjected to three treatments consisting in different storage conditions: cold storage at low and high moisture conditions, plus a control. Five replicates of up to 30 seeds were placed under constant temperature conditions and germination was monitored weekly during 14 weeks. & Results The effect of cold storage at high moisture on germination differed between the three species and seed source played a significant role in the germination of all three species. In the case of the species with dormancy, the observed differences in germination could reflect changes in the spe-cies' dormancy degree or sensitivity to dormancy breaking factors across their geographical range. In the case of Pistacia lentiscus (no dormancy), the results suggested a possible adaptation of the northern seed source to high moisture conditions. & Conclusions The observed differences between species agreed well with their dormancy types, and the seed source-related differences could be adaptive features, as they seemed related with local climate conditions.
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- "Conservation seed banks can establish and maintain genetically and geographically representative samples of wild plant germplasm able to be used years, decades, or even centuries into the future (Walters et al. 2005; Li and Pritchard 2009). Seed banks also have a major role to play in facilitating the restoration of degraded land (Merritt and Dixon 2011). The longevity of orthodox (desiccation tolerant) seeds increases as seed moisture content and storage temperature is reduced (Ellis and Roberts 1980). "
ABSTRACT: Management of seed banks conserving the biodiversity of phylogenetically diverse species requires insight into seed longevity. This study determined the seed longevity of 172 species sourced from across the mega-diverse flora of the Australia continent. Seeds were aged via a controlled ageing experiment through storage at 45 °C and 60 % RH, or 60 °C and 60 % RH, and regularly tested for germination. Relative seed longevity between species was determined by comparing the time to 50 % viability loss (p 50), calculated via probit analysis of seed survival curves. Seed, plant, and environmental traits were examined for associations with longevity. The p 50 values varied between species from 3.0 to 588.6 days. Serotinous species, and woody trees and shrubs, had significantly longer-lived seeds than geosporous species, and species of herbaceous habit. Seeds that possess physical dormancy, and seeds with large embryos with little endosperm, were also long-lived. There was a weak, but significant, positive correlation between seed mass and longevity. Seeds sourced from regions of higher mean annual temperature and rainfall were significantly longer-lived than seeds from cooler and drier regions, although both environmental factors were weakly associated with longevity. Compared with species from other regions of the world, prolonged longevity is a feature of many Australian species. Nevertheless, seed life-spans vary substantially between species and close consideration of seed traits along with biotic and abiotic components of the plants and their environment can assist to differentiate between potentially long- and short-lived seeds.