A framework for the practical science necessary to restore sustainable, resilient, and biodiverse ecosystems

Demand for restoration of resilient, self-sustaining, and biodiverse natural ecosystems as a conservation measure is increasing globally; however, restoration efforts frequently fail to meet standards appropriate for this objective. Achieving these standards requires management underpinned by input from diverse scientific disciplines including ecology, biotechnology, engineering, soil science, ecophysiology, and genetics. Despite increasing restoration research activity, a gap between the immediate needs of restoration practitioners and the outputs of restoration science often limits the effectiveness of restoration programs. Regrettably, studies often fail to identify the practical issues most critical for restoration success. We propose that part of this oversight may result from the absence of a considered statement of the necessary practical restoration science questions. Here we develop a comprehensive framework of the research required to bridge this gap and guide effective restoration. We structure questions in five themes: (1) setting targets and planning for success, (2) sourcing biological material, (3) optimizing establishment, (4) facilitating growth and survival, and (5) restoring resilience, sustainability, and landscape integration. This framework will assist restoration practitioners and scientists to identify knowledge gaps and develop strategic research focused on applied outcomes. The breadth of questions highlights the importance of cross-discipline collaboration among restoration scientists, and while the program is broad, successful restoration projects have typically invested in many or most of these themes. Achieving restoration ecology's goal of averting biodiversity losses is a vast challenge: investment in appropriate science is urgently needed for ecological restoration to fulfill its potential and meet demand as a conservation too

Seed germination traits can contribute better to plant community ecology

Analyses of functional traits have become fundamental tools for understanding patterns and processes in plant community ecology. In this context, regenerative seed traits play an important, yet overlooked, role because they largely determine the ability of plants to disperse and re-establish. A survey of recent publications in community ecology suggests that seed germination traits in particular are neglected at the expense of other relevant but overused traits based only on seed morphology. As a response to this bias, we discuss the functional significance of seed germination traits in comparison with morphological and biophysical seed traits, and advocate their use in vegetation science. We also demonstrate how research in community assembly, climate change and restoration ecology can benefit from the inclusion of germination traits, encompassing functions that cannot be explained solely by adult plant traits. Seed germination experiments conducted in the laboratory or field to quantify these traits provide ecologically meaningful and relatively easy-to-obtain information about the functional properties of plant communities. We argue that bridging the gap between seed physiologists and community ecologists will improve the prediction of plant assemblages, and propose further perspectives for including seed traits into the research agenda of functional community ecologists

The role of after-ripening in promoting germination of arid zone seeds: a study on six Australian species

The effects of after-ripening (storage under warm, dry conditions) on seed germination was examined in six plant species from the arid zone of Western Australia with the aim of improving germination and germination rate for rehabilitation objectives. Study species (Acanthocarpus preissii, Anthocercis littorea, Dioscorea hastifolia, Eremophila oldfieldii, Thryptomene baeckeacea and Zygophyllum fruticulosum) were selected based on diverse plant habits, seed types and requirements for rehabilitation. After-ripening was investigated by adjusting seed moisture content to 13 and 50 equilibrium relative humidity (eRH) at 23 °C and storing seeds at two temperatures (30 and 45 °C) from 1 to 18 months. Following storage, seeds were incubated in water, gibberellic acid (GA3) or karrikinolide (KAR1; the butenolide, 3-methyl-2H-furo[2,3-c]pyran-2-one). All after-ripening conditions increased germination percentage and rate of A. littorea and D. hastifolia, with A. littorea only germinating when treated with GA3 or KAR1. The germination of Z. fruticulosum was dependent on after-ripening temperature and seed moisture content. After-ripening had a limited effect on the remaining three species. The restoration implications of the findings are discussed

Germination behaviour of Astroloma xerophyllum (Ericaceae), a species with woody indehiscent endocarps

The dispersal unit of many Ericaceae comprises an ovoid drupe with a woody indehiscent endocarp, and diaspores of this type are notoriously difficult to germinate for most members of this widely distributed family. Within the biodiverse south-west of Western Australia, more than 200 drupaceous species of Ericaceae have been described, more than 50 of which are considered to be rare and threatened, requiring significant conservation action in the near future. In this paper, we investigate the germination ecology of the common Australian endemic, Astroloma xerophyllum, as a proxy for closely related threatened taxa, focusing on the ex situ and in situ germination requirements of seeds and indehiscent endocarps. Each endocarp possessed up to seven locules and means of 2.0–3.4 seeds per endocarp from the two collections used in this study. Seeds were up to 2.74 mm in length and 100% viable. Embryos were linear, differentiated and approximately 1.3 mm in length. Seeds within endocarps imbibed water to 28%, whereas excised seeds became hydrated to 44%. Fifty-five per cent of seeds extracted from endocarps germinated on water agar alone and 100% germinated when presoaked in gibberellic acid. Seeds remaining inside intact endocarps failed to germinate unless treated with a germination promoter and incubated for more than 20 weeks. Rapid germination of seeds in intact endocarps was promoted by soaking endocarps in gibberellic acid and incubating them in 100% O2. Embryos grew substantially in length within seeds prior to germination, and thus seeds have morphophysiological dormancy. Seeds under natural conditions required several seasons to germinate to any degree

Seed germinability and longevity influences regeneration of Acacia gerrardii

Acacia gerrardii is the only native tree species of the Kuwaiti desert ecosystem. However, anthropogenic disturbances and harsh arid climate have contributed towards the disappearance of this keystone species from its habitat. In this study, effects of different seed pretreatments to break dormancy, water entry pathway, and ecology (seasonal timing) of dormancy loss and germination of A. gerrardii were investigated. Effects of mechanical scarification, hot water treatment (30 s, 1, 2, and 5 min), and concentrated acid scarification (10, 20, and 30 min) on germination percentage and rate (time to 50% germination and final germination) were also examined. Pretreatment with mechanical scarification produced the highest germination in the least time and 20 °C, 40% RH with 12 h of light (2370 Lux) were found to provide the best germination environment. Seeds were rapidly aged at 60% RH and 45 or 50 °C to determine longevity, and the results were analyzed using probit analysis. Times taken for viability of A. gerrardii seeds aged at 45 and 50 °C to fall to 50% (p50) were 38.6 and 9.3 days, respectively, and therefore the seeds can be considered to have medium longevity. Experiments to find the water entry pathway in A. gerrardii indicated that the micropyle region was the primary point of water entry into the seed. Seed burial experiments indicated that though seed retention decreased over time, there was no significant decrease in number of viable seeds after 31 weeks. The findings of this study are important to nursery managers, seed banks, and those involved in conservation and restoration activities