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Rajapakshe RPVGSW, Tomlinson S, Tudor EP, Turner SR, Elliott CP, Lewandrowski W. Same, same, but different: dissimilarities in the hydrothermal germination performance of range-restricted endemics emerge despite microclimatic similarities. CONSERVATION PHYSIOLOGY 2024; 12:coae009. [PMID: 38487732 PMCID: PMC10939308 DOI: 10.1093/conphys/coae009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 01/17/2024] [Accepted: 01/24/2024] [Indexed: 03/17/2024]
Abstract
Seed germination responses for most narrow-range endemic species are poorly understood, imperilling their conservation management in the face of warming and drying terrestrial ecosystems. We quantified the realized microclimatic niches and the hydrothermal germination thresholds in four threatened taxa (Tetratheca erubescens, Tetratheca harperi, Tetratheca paynterae subsp. paynterae and Tetratheca aphylla subsp. aphylla) that are restricted to individual Banded Ironstone Formations in Western Australia. While T. aphylla subsp. aphylla largely failed to germinate in our trials, all other species demonstrated extended hydrothermal time accumulation (186-500°C MPa days), cool minimum temperatures (7.8-8.5°C), but broad base water potential thresholds (-2.46 to -5.41 MPa) under which germination occurred. These slow germination dynamics are suggestive of cool and wet winter months, where soil moisture is retained to a greater capacity in local microsites where these species occur, rather than the warmer and drier conditions in the surrounding arid environment. Hydrothermal time-to-event modelling showed that each species occupied unique hydrothermal germination niches, which correspond with the microclimatic differences the species are exposed to. Our results provide a baseline understanding for environmental and germination thresholds that govern the recruitment, and ultimately the population structure and persistence, of these short-range endemic plants. In addition, our results can aid future conservation, as well as restoration actions such as translocation to bolster population numbers and to mitigate against losses due to anthropogenic disturbance and global environmental change.
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Affiliation(s)
- Rajapakshe P V G S W Rajapakshe
- ARC Centre for Mine Site Restoration, Curtin University, Bentley, 6102, Australia
- School of Molecular and Life Sciences, Curtin University, Bentley, 6102, Australia
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, Kings Park, 6005, Australia
| | - Sean Tomlinson
- School of Molecular and Life Sciences, Curtin University, Bentley, 6102, Australia
- School of Biological Sciences, University of Adelaide, Adelaide, 5000, Australia
| | - Emily P Tudor
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, Kings Park, 6005, Australia
- School of Biological Sciences, University of Western Australia, Crawley, 6009, Australia
| | - Shane R Turner
- ARC Centre for Mine Site Restoration, Curtin University, Bentley, 6102, Australia
- School of Molecular and Life Sciences, Curtin University, Bentley, 6102, Australia
| | - Carole P Elliott
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, Kings Park, 6005, Australia
- School of Biological Sciences, University of Western Australia, Crawley, 6009, Australia
| | - Wolfgang Lewandrowski
- Kings Park Science, Department of Biodiversity, Conservation and Attractions, Kings Park, 6005, Australia
- School of Biological Sciences, University of Western Australia, Crawley, 6009, Australia
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Just M, Turner S, Cross A, Lewandrowski W, Pedrini S, Dixon K. Germination physiology of Cochlospermum fraseri (Bixaceae), a deciduous tree from Northern Australia with physical seed dormancy. CONSERVATION PHYSIOLOGY 2023; 11:coad057. [PMID: 37671236 PMCID: PMC10476509 DOI: 10.1093/conphys/coad057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/28/2023] [Accepted: 07/19/2023] [Indexed: 09/07/2023]
Abstract
Cochlospermum fraseri ('Kapok', Bixaceae) is a deciduous tree widely distributed throughout semi-arid and monsoon tropical northern Australia, and an important species for ecological restoration in the region. We aimed to better understand the seed biology and ecology of C. fraseri to determine the mechanisms by which seed dormancy might be alleviated, and the conditions that support germination to inform the use of this species in restoration. Dormancy breaking treatments (wet heat, dry heat, scarification) commonly applied to species with physical seed dormancy (PY) were tested along with stratification at 5-35°C (nine treatments). Following dormancy alleviation, seeds were germinated at nine temperatures (5 to 40°C) and five water potentials (0 to -0.8 MPa) to understand environmental thresholds that regulate germination physiology in non-dormant seeds. A proportion of seeds (<0.3) lose dormancy naturally in response to warm (25 to 35°C) moist conditions, which dislodges the hypostase plug that prevents water uptake, whilst neither dry (≥100°C) nor wet (~100°C) heat were effective. Dormancy loss was also achieved by exposing seeds to concentrated (95-98% v/v) sulphuric acid for 3-7 hours, after which high proportions (>0.75) of germination were observed. Cochlospermum fraseri seeds possess PY, which is alleviated by seasonal temperatures that occur when soil moisture is high, allowing seeds to employ a risk-adverse strategy and maximize establishment success in episodic environments with stochastic rainfall events. The understanding of dormancy alleviation requirements gained here adds to our knowledge of PY worldwide and recruitment dynamics in the Australian monsoonal tropics and will aid land managers and restoration practitioners by informing both seeding sites and optimal time for in situ sowing as well as the potential capacity of this species to form a persistent soil seed bank.
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Affiliation(s)
- Michael Just
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, Western Australia 6102, Australia
| | - Shane Turner
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, Western Australia 6102, Australia
| | - Adam Cross
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, Western Australia 6102, Australia
- Ecological Health Network, 1330 Beacon St, Suite 355a, Brookline, Massachusetts 02446, United States of America
| | - Wolfgang Lewandrowski
- Department of Biodiversity, Conservation and Attractions, Kings Park Science, Fraser Avenue, Kings Park, Western Australia 6005, Australia
- School of Biological Sciences, University of Western Australia, Stirling Highway, Crawley, Western Australia 6009, Australia
| | - Simone Pedrini
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, Western Australia 6102, Australia
| | - Kingsley Dixon
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, Western Australia 6102, Australia
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Zomer M, Moreira B, Pausas JG. Fire and summer temperatures interact to shape seed dormancy thresholds. ANNALS OF BOTANY 2022; 129:809-816. [PMID: 35390121 PMCID: PMC9292603 DOI: 10.1093/aob/mcac047] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 04/05/2022] [Indexed: 05/05/2023]
Abstract
BACKGROUND AND AIMS In Mediterranean ecosystems, the heat shock of wildfire disrupts physical seed dormancy in many plant species. This triggers germination in the post-fire environment where seedling establishment is optimal due to decreased competition and increased resource availability. However, to maintain the soil seed bank until a fire occurs, the minimum heat capable of breaking seed dormancy (i.e. the lower heat threshold) must be above the maximum temperatures typically observed in the soil during the summer. We therefore hypothesized that summer temperatures have shaped heat requirements for physical dormancy release. Specifically, we predicted that seeds from populations growing under warmer summers will have higher values of the lower heat threshold. METHODS To evaluate this prediction, we collected seeds from two Cistus species in 31 populations (20 Cistus albidus and 11 Cistus salviifolius) along a climate gradient of summer temperatures on the eastern coast of Spain. For each population, seeds were treated to 10 min heat shocks, from 30 to 120 °C in 5 °C increments (19 treatments), to simulate increasing heat doses from summer to fire-related temperatures. Seeds were then germinated in the lab. KEY RESULTS For all populations, maximum germination was observed when applying temperatures associated with fire. Lower heat thresholds varied among populations, with a positive relationship between summer temperatures at seed population origin and the heat dose required to break dormancy. CONCLUSIONS Our results suggest that fire drives maximum dormancy release for successful post-fire germination, while summer temperatures determine lower heat thresholds for ensuring inter-fire seed bank persistence. Significant among-population variation of thresholds also suggests that post-fire seeder species have some potential to modify their dormancy release requirements in response to changing climate.
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Affiliation(s)
- Maya Zomer
- Centro de Investigaciones sobre Desertificación (CIDE-CSIC), Ctra. Náquera Km. 4.5, Moncada, E-46113 Valencia, Spain
| | - Bruno Moreira
- Centro de Investigaciones sobre Desertificación (CIDE-CSIC), Ctra. Náquera Km. 4.5, Moncada, E-46113 Valencia, Spain
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Rajapakshe RPVGSW, Cross AT, Turner SR, Tomlinson S. Understanding the interplay of temperature and moisture on the germination niche to improve management of threatened species impacted by mining. Restor Ecol 2022. [DOI: 10.1111/rec.13708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Rajapakshe P. V. G. S. W. Rajapakshe
- ARC Centre for Mine Site Restoration, School of Molecular and Life Sciences Curtin University Bentley WA 6102 Australia
- School of Molecular and Life Sciences Curtin University Bentley Western Australia 6102 Australia
- Kings Park Science, Department of Biodiversity Conservation and Attractions Kings Park Western Australia 6005 Australia
| | - Adam T. Cross
- ARC Centre for Mine Site Restoration, School of Molecular and Life Sciences Curtin University Bentley WA 6102 Australia
- School of Molecular and Life Sciences Curtin University Bentley Western Australia 6102 Australia
- EcoHealth Network, 1330 Beacon St, Suite 355a Brookline MA 02446 United States
| | - Shane R. Turner
- ARC Centre for Mine Site Restoration, School of Molecular and Life Sciences Curtin University Bentley WA 6102 Australia
- Kings Park Science, Department of Biodiversity Conservation and Attractions Kings Park Western Australia 6005 Australia
- School of Biological Sciences University of Western Australia Crawley Western Australia 6009 Australia
| | - Sean Tomlinson
- School of Molecular and Life Sciences Curtin University Bentley Western Australia 6102 Australia
- Kings Park Science, Department of Biodiversity Conservation and Attractions Kings Park Western Australia 6005 Australia
- School of Biological Sciences, University of Adelaide, North Terrace Adelaide South Australia 5000 Australia
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Tomlinson S, Tudor EP, Turner SR, Cross S, Riviera F, Stevens J, Valliere J, Lewandrowski W. Leveraging the value of conservation physiology for ecological restoration. Restor Ecol 2021. [DOI: 10.1111/rec.13616] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Sean Tomlinson
- School of Biological Sciences, University of Adelaide, North Terrace Adelaide South Australia 5000 Australia
- School of Molecular and Life Sciences, Curtin University Bentley Western Australia 6102 Australia
- Kings Park Science, Department of Biodiversity, Conservation and Attractions Kings Park, Western Australia 6005 Australia
| | - Emily P. Tudor
- School of Molecular and Life Sciences, Curtin University Bentley Western Australia 6102 Australia
- Kings Park Science, Department of Biodiversity, Conservation and Attractions Kings Park, Western Australia 6005 Australia
- School of Biological Sciences, University of Western Australia Crawley Western Australia 6009 Australia
| | - Shane R. Turner
- Kings Park Science, Department of Biodiversity, Conservation and Attractions Kings Park, Western Australia 6005 Australia
- ARC Centre for Mine Site Restoration, School of Molecular and Life Sciences, Curtin University Bentley WA 6102 Australia
- School of Biological Sciences, University of Western Australia Crawley Western Australia 6009 Australia
| | - Sophie Cross
- ARC Centre for Mine Site Restoration, School of Molecular and Life Sciences, Curtin University Bentley WA 6102 Australia
| | - Fiamma Riviera
- ARC Centre for Mine Site Restoration, School of Molecular and Life Sciences, Curtin University Bentley WA 6102 Australia
- School of Biological Sciences, University of Western Australia Crawley Western Australia 6009 Australia
| | - Jason Stevens
- Kings Park Science, Department of Biodiversity, Conservation and Attractions Kings Park, Western Australia 6005 Australia
- ARC Centre for Mine Site Restoration, School of Molecular and Life Sciences, Curtin University Bentley WA 6102 Australia
- School of Biological Sciences, University of Western Australia Crawley Western Australia 6009 Australia
| | - Justin Valliere
- Department of Biology California State University Dominguez Hills Carson California 90747 US
| | - Wolfgang Lewandrowski
- Kings Park Science, Department of Biodiversity, Conservation and Attractions Kings Park, Western Australia 6005 Australia
- School of Biological Sciences, University of Western Australia Crawley Western Australia 6009 Australia
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Valliere JM, Ruscalleda Alvarez J, Cross AT, Lewandrowski W, Riviera F, Stevens JC, Tomlinson S, Tudor EP, Wong WS, Yong JWH, Veneklaas EJ. Restoration ecophysiology: an ecophysiological approach to improve restoration strategies and outcomes in severely disturbed landscapes. Restor Ecol 2021. [DOI: 10.1111/rec.13571] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Justin M. Valliere
- Department of Biology California State University Dominguez Hills Carson CA 90747 U.S.A
- School of Biological Sciences The University of Western Australia Crawley WA 6009 Australia
- ARC Centre for Mine Site Restoration Curtin University Bentley WA 6102 Australia
| | - Jaume Ruscalleda Alvarez
- School of Biological Sciences The University of Western Australia Crawley WA 6009 Australia
- ARC Centre for Mine Site Restoration Curtin University Bentley WA 6102 Australia
| | - Adam T. Cross
- ARC Centre for Mine Site Restoration Curtin University Bentley WA 6102 Australia
- EcoHealth Network, 1330 Beacon Street Brookline MA 02446 U.S.A
- School of Molecular and Life Sciences Curtin University Bentley WA 6102 Australia
| | - Wolfgang Lewandrowski
- School of Biological Sciences The University of Western Australia Crawley WA 6009 Australia
- Kings Park Science Department of Biodiversity Conservation and Attractions Kings Park WA 6005 Australia
| | - Fiamma Riviera
- School of Biological Sciences The University of Western Australia Crawley WA 6009 Australia
- ARC Centre for Mine Site Restoration Curtin University Bentley WA 6102 Australia
| | - Jason C. Stevens
- School of Biological Sciences The University of Western Australia Crawley WA 6009 Australia
- ARC Centre for Mine Site Restoration Curtin University Bentley WA 6102 Australia
- Kings Park Science Department of Biodiversity Conservation and Attractions Kings Park WA 6005 Australia
| | - Sean Tomlinson
- ARC Centre for Mine Site Restoration Curtin University Bentley WA 6102 Australia
- Kings Park Science Department of Biodiversity Conservation and Attractions Kings Park WA 6005 Australia
- School of Biological Sciences The University of Adelaide Adelaide SA 5005 Australia
| | - Emily P. Tudor
- School of Biological Sciences The University of Western Australia Crawley WA 6009 Australia
- School of Molecular and Life Sciences Curtin University Bentley WA 6102 Australia
- Kings Park Science Department of Biodiversity Conservation and Attractions Kings Park WA 6005 Australia
| | - Wei San Wong
- School of Biological Sciences The University of Western Australia Crawley WA 6009 Australia
- ARC Centre for Mine Site Restoration Curtin University Bentley WA 6102 Australia
| | - Jean W. H. Yong
- School of Biological Sciences The University of Western Australia Crawley WA 6009 Australia
- ARC Centre for Mine Site Restoration Curtin University Bentley WA 6102 Australia
- Department of Biosystems and Technology Swedish University of Agricultural Sciences Alnarp Sweden
| | - Erik J. Veneklaas
- School of Biological Sciences The University of Western Australia Crawley WA 6009 Australia
- ARC Centre for Mine Site Restoration Curtin University Bentley WA 6102 Australia
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Cross AT, Lambers H. Calcicole-calcifuge plant strategies limit restoration potential in a regional semi-arid flora. Ecol Evol 2021; 11:6941-6961. [PMID: 34141267 PMCID: PMC8207153 DOI: 10.1002/ece3.7544] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 03/17/2021] [Accepted: 03/23/2021] [Indexed: 01/06/2023] Open
Abstract
AIM To examine calcicole and calcifuge plant strategies, as well as nutrient-acquisition strategies, as drivers of the distribution of species in response to edaphic factors, and the degree to which these strategies may act as filters to species establishment in ecological restoration on heavily altered or reconstructed substrates. LOCATION An 82,000-ha area within a major mining province in the Mid-West region of Western Australia, harboring vegetation communities ranging from species-poor halophytic scrub on saline flats to dense biodiverse shrubland on the skeletal soils of ancient Banded Ironstone Formations (BIF). METHODS Univariate and multivariate analyses were employed to examine how variation in soil chemistry and landscape position (undulating plains, slopes, and BIF crests and ridges) influenced patterns of floristic diversity, calcifuge plant strategies, and nutrient-acquisition strategies in 538 plant species from 830 relevés. RESULTS Landscape position was the strongest driver of species richness and vegetation functional composition. Soils became increasingly acidic and P-impoverished along an increasing elevational gradient. Vegetation from different landscape positions was not compositionally dissimilar, but vegetation of BIF crests and ridges was up to twice as biodiverse as vegetation from adjacent lower-relief areas and harbored higher proportions of calcifuge species and species with mycorrhizal associations. MAIN CONCLUSIONS Topographic and edaphic complexity of BIF landforms in an otherwise relatively homogenous landscape has likely facilitated species accumulation over long time periods. They represent musea of regional floristic biodiversity, excluding only species that cannot establish or are inferior competitors in heavily weathered, acidic, skeletal, and nutrient-impoverished soils. Plant strategies likely represent a major filter in establishing biodiverse, representative vegetation on postmining landforms in geologically ancient regions.
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Affiliation(s)
- Adam T. Cross
- School of Molecular and Life SciencesCurtin UniversityBentleyWAAustralia
- EcoHealth NetworkBrooklineMAUSA
| | - Hans Lambers
- School of Molecular and Life SciencesCurtin UniversityBentleyWAAustralia
- School of Biological SciencesThe University of Western AustraliaPerthWAAustralia
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Cross AT, Zhong H, Lambers H. Incorporating rock in surface covers improves the establishment of native pioneer vegetation on alkaline mine tailings. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 768:145373. [PMID: 33736352 DOI: 10.1016/j.scitotenv.2021.145373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/17/2021] [Accepted: 01/18/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND AIMS Rates of tailings production and deposition around the world have increased markedly in recent decades, and have grown asynchronously with safe and environmentally suitable solutions for their storage. Tailings are often produced in regions harbouring biodiverse native plant communities adapted to old, highly-weathered soils. The highly-altered edaphic conditions of tailings compared with natural soils in these areas will likely select against many locally endemic plant species, making phytostabilisation, rehabilitation or ecological restoration of these landforms challenging. METHODS We established four substrate cover composition treatments on a dry-stacked magnetite tailings storage facility in semi-arid Western Australia, representative of standard industry practices for rehabilitating or restoring post-mining landforms in the region. Plots were seeded with a selection of locally native plant species and monitored for five years to determine whether different substrate cover treatments yielded different edaphic conditions (soil moisture, substrate surface temperature and substrate chemistry) and influenced soil development and the success of native vegetation establishment. RESULTS No vegetation established from seeds on unamended tailings with no surface cover, and substrate chemistry changed minimally over five years. In contrast, rock-containing surface covers allowed establishment of up to 11 native plant species from broadcast seeds at densities of ca. 1.5 seedlings m-2, and up to 3.5 seedlings m-2 of five native pioneer chenopods from capture of wind-dispersed seeds from surrounding undisturbed native vegetation. Greater vegetation establishment in rock-containing surface covers resulted from increased heterogeneity (e.g., lower maximum soil temperature, greater water capture and retention, surface microtopography facilitating seed capture and retention, more niches for seed germination). Soil development and bio-weathering occurred most rapidly under the canopy of native pioneer plants on rock-containing surface covers, particularly increases in organic carbon, total nitrogen, and organo-bound aluminium and iron. CONCLUSIONS Seed germination and seedling survival on tailings were limited by extreme thermal and hydrological conditions and a highly-altered biogeochemical environment. The design of surface cover layers appears crucial to achieving closure outcomes on tailings landforms, and designs should prioritise increasing surface heterogeneity through the incorporation of rock or other structure-improving amendments to assist the establishment of pioneer vegetation.
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Affiliation(s)
- Adam T Cross
- School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, WA 6102, Australia; EcoHealth Network, 1330 Beacon St, Suite 355a, Brookline, MA 02446, United States.
| | - Hongtao Zhong
- School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - Hans Lambers
- School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia; Centre for Mine Site Restoration, School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, WA 6102, Australia
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Tomlinson S. The construction of small‐scale, quasi‐mechanistic spatial models of insect energetics in habitat restoration: A case study of beetles in Western Australia. DIVERS DISTRIB 2020. [DOI: 10.1111/ddi.13074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- Sean Tomlinson
- School of Molecular and Life Sciences Curtin University of Technology Perth WA Australia
- Department of Biodiversity, Conservation an Attractions Kings Park Science Kings Park WA Australia
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