Seed Bank Research Articles

Reproductive Biology in the Possible Last Healthy Population of Parodia rechensis (Cactaceae): Perspectives to Avoid Its Extinction.

All 32 Brazilian species of Parodia Speg (Cactaceae) occurring in Rio Grande do Sul State are considered threatened, according to the IUCN criteria. Until 2021, Parodia rechensis (CR) was known by only two small populations. However, a new population with over 400 individuals was discovered in 2021, prompting the study of its reproductive biology as a way to promote its conservation. Anthesis, breeding system, and natural pollination were studied in the field. The breeding system was studied by applying controlled pollination treatments to plants excluded from pollinators (bagged). Germination features were studied at the Seed Bank of the Porto Alegre Botanical Garden under controlled temperatures (20, 25, and 30 °C). The anthesis is diurnal and lasts for up to four days. The flowers offer pollen as the sole resource to the pollinators. The study species is unable to set fruit and seed without the agency of pollinators and has self-incompatible (unable to set fruit and seeds when pollinated with pollen of the same individual) characteristics that can considerably restrict its reproduction. Native bees of Halictidae and Apidae (Hymenoptera) are the main pollinators, with a smaller contribution of Melyridae (Coleoptera) and Syrphidae (Diptera). Natural fruit set is moderate (≤64%, per individual), but the species presents vegetative growth, producing several branches from the mother plant. Seeds showed the optimum germination rate at 20 °C and an inhibition of 75% in germinability at 30 °C. Our findings suggest the need to manage the species' habitat to guarantee the permanency of the plants and healthy populations of pollinators as well. Our findings raise concerns about the germination and establishment of new individuals in the context of rising temperatures caused by climate change. Suggestions for the possible management of the extant populations are made.

Promising Strategies to Enhance the Sustainability of Community Seed Banks

Community seed banks are farmer-managed organizations that conserve and sustainably manage local crop and tree diversity. They are found in many countries of the Global South and increasingly in the Global North. Altogether, they maintain hundreds of crop and tree species and thousands of mostly local varieties and distribute tons of quality seed per year. Through their activities, they share and safeguard the world’s agrobiodiversity, contribute to seed security, and allow farming households in local communities to produce and consume more affordable, secure, diverse, and nutritious foods. However, community seed banks are knowledge-, resource-, and time-intensive organizations that operate through their members’ voluntary contributions. The purpose of this article is to analyze the sustainability challenge of community seed banks and identify strategies that address it. Focus group discussions and key informant interviews were used, complemented by secondary data analysis of research reports and other deliverables, resulting in five case study countries in Africa and Asia. Five promising sustainability strategies can support viable community seed bank development: value addition; nature-positive agriculture; enabling environment and national genebank partnership; networking and digitalization; and modern, low-cost seed quality technologies. Sustainable community seed banks can make important contributions to national seed sector development but they need stronger policy and legal support to maintain their sustainability.

Streamlining Workflows for the Digitisation of New Acquisition Herbarium Specimens: Meeting Archive Service Accreditation Standards amid Mass Digitisation

The herbarium at the Royal Botanic Gardens, Kew*1 (RBG Kew) houses around seven million pressed, dried plants, making it one of the largest herbaria globally. Acting as a reference library for plants, the collection is arranged according to the botanical tree of life and represents over 95% of vascular plant genera worldwide. It is actively used for scientific study and is contacted daily by taxonomists, conservationists, artists and historians interested in the collection’s wide-ranging specimens. In October 2021, funding was secured for a 4-year project to digitise the entire herbarium and fungarium collections. The goal is to create a complete, freely accessible online catalogue of these collections for researchers across the world, so they can be used in aiding efforts to combat urgent global challenges such as habitat degradation, climate change and human health. Simultaneously, RBG Kew is seeking Archive Service Accreditation*2, which uses United Kingdom sector standards, Spectrum*3, as a benchmark for best practices. It encourages better management of collections, increased efficiency across operations and raises collections accessibility. Ultimately, it ensures collections are governed appropriately and provides a guide for staff to engage with collections sustainably, protecting them for the future. These two initiatives underpin the importance of effectively curating images, digital records, and physical specimens, subsequently requiring RBG Kew to review and alter workflows to maintain and enhance the expanding dataset. In this paper, we discuss the workflow development for the digitisation and integration of our annual fifteen thousand to twenty thousand new accession specimens, accounting for the large-scale digitisation project, accreditation requirements and existing workflows. After initial research and collaboration with key stakeholders, five pilot workflows were proposed to manage and digitise our newly acquired material. These workflows explored options including databasing post-curation and imaging after mounting; complete digitisation occurring post-curation and mounting; and using transaction numbers to track specimens between object entry and accessioning instead of barcodes. The most promising option, based on stakeholder feedback, was piloted and iterated over two years, ultimately becoming the collection operating procedure (COP) for new material entering the herbarium (Fig. 1). The current COP has three fundamental elements: Traceability of an object based on consignment information. Integration with existing procedures and consistency between curation teams. Definition of a specimen’s legal status throughout the procedure. Traceability of an object based on consignment information. Integration with existing procedures and consistency between curation teams. Definition of a specimen’s legal status throughout the procedure. For traceability, RBG Kew’s new Integrated Collection Management System (ICMS), EarthCape*4, means a transaction number can be added to each individual object. Upon arrival, a transaction record, containing all legal and transactional information, is created with a unique ID. This ID is printed onto a hanging label attached to each specimen bundle. The digitisation team is then able to assign a unique catalogue number to every specimen, database the label data into ICMS and link each object to the transaction record using the transaction ID, providing the ability to view all consignment information through a specimen record. The legal status for a specimen at this step is “Object Entry.” The specimens then enters the pre-existing workflow for newly acquired material, where the curatorial and research teams assess it for keeping, further identification, preparation and mounting. Since the specimens are not yet accessioned or under Kew’s legal custodianship, any material can be disposed via destruction, gifting or returned to its owner without deaccessioning at this point. Once mounted, the specimen returns to digitisation for imaging. At this point, the specimen is officially considered part of Kew’s collection, and its legal status is updated to Accessioned or Acquired-Custodianship, based on Kew’s legal ownership, recorded in the consignment. As a result of the pilot and subsequent workflow changes, there was additionally the requirement for flexibility to incorporate material from collections that have different and often more complex requirements to the standard museum material. This culminated in adaptations to process material from the Millennium Seed Bank*5, DNA & Tissue Bank*6, Living Collection*7, as well as outgoing and returning loans. Next steps for new acquisitions at RBG Kew involve developing procedures for inter-institutional digital data and physical specimen exchange, which are currently in the research and trial phase, as well as creating streamlined methods for digital data collection in the field.

Parable of the Svalbard Seed Vault: An Arctic repository for agricultural plant diversity embodies the flawed logic of climate adaptation.

Parable of the Svalbard Seed Vault: An Arctic repository for agricultural plant diversity embodies the flawed logic of climate adaptation.

Genetic Diversity Assessment of Brinjal Germplasm for Varietal Improvement

Forty-one (41) brinjal (Solanum melongena L.) germplasm of were evaluated at the field of Plant Genetic Resources Centre, BARI, Gazipur to identify the salient features and to assess genetic divergence of germplasm in the time of rabi season 2021-22. Distinct variation was observed in qualitative characters among the germplasm except two characters i.e. fruit cross section and fruit position. For the characters length breath ratio and calyx prickles of fruit, the topmost variation was found. In case of quantitative characters, variation was noticed maximum in the length of fruit (CV-43.79%), afterwards individual weight of fruit (CV-32.91%) and yield plant-1 (CV-30.12%). The highest number of germplasm was dispersed into cluster I. Among the clusters, cluster II and cluster III were occupied by ten germplasm, respectively. Cluster mean value was noted maximum in cluster II for the characters days required for 50% flowering (67.90%), plant height (97.97 cm), individual fruit weight (107.35 g), and yield plant-1 (2.51%). Among the principal components, 27.28% of the total variation interpreted by the first PC and the second PC clarified 22.36% of the variation. In the biplot, germplasm NF-15, NF-20, NF-13, NF-7, NF-4, NF-25, NF-16, and NF-2 etc. were independently far away from the studied germplasm by keeping a distance from the centroid. These results displayed distinctiveness and divergence of germplasm as regards of the studied traits. Populations with high values for the first eigen vectors are individual fruit weight (0.642), yield plant-1 (0.564), and width of fruit (0.313), these characters were the utmost significant contributors towards the diversity of germplasm in PC1. The germplasm NF-4 (3.45 kg), NF-30 (3.38 kg), and NF-25 (3.08 kg) were higher yielders among the tested germplasm and may be used for future varietal improvement of brinjal. J. of Sci. and Tech. Res. 5(1): 21-29, 2023

Conservation and Utilization of Summer Crops Biodiversity in Nepal

Nepal faces a pressing challenge with the alarming loss of around 50% of its summer crop genetic resources (SCGRs) and the endangerment of native landraces. To combat this decline, the national genebank in Nepal has developed 101 good practices for agricultural genetic resources (AGRs) conservation and utilization. Red zoning and red listing strategies aid in identifying conservation priorities. The Genebank collaborates with stakeholders to collect, characterize, and promote SCGRs, resulting in 6177 accessions representing 71 summer crop species stored in Seed Banks. Diverse conservation repositories include genebanks, tissue banks, DNA banks, community genebanks, school field genebanks, and agro-gene sanctuaries. In 2022, 724 accessions of 20 summer crops were distributed for research, while the registration of 19 landraces after genetic enhancements led to their inclusion under the National Seed Board. The free distribution of germplasm accelerates its utilization, further facilitated by online access. The genebank also promotes agro-insect field genebanks recognizing the importance of agro-insects and pollinators in biodiversity conservation. To maintain native SCGRs, value additions are emphasized, underlining the need to actively enhance genetic diversity in agricultural fields. These comprehensive measures underscore Nepal’s commitment to safeguarding agrobiodiversity, ensuring food security, and bolstering agricultural resilience to climate and other stresses.

Herbicidal Effects of Pyroligneous Acid for Control in Weed Seed Bank

Aims: Pyroligneous liquor, a by-product extracted from wood pyrolysis during charcoal production, is mainly discarded. Pyroligneous liquor has a phytotoxic effect and can be used environmentally as an herbicide of natural and sustainable origin for plant control. The objective of this research was to evaluate the effectiveness of pyroligneous liquor to control the plant seed bank. Study Design: Different concentrations of pyroligneous liquor (0, 1, 2, 3, 4, 5, 10, 15, 20, 25, 50, 75, 100% (v/v)) were tested in soil samples with 10 replications each. Statistical analysis of the data found was carried out using the OriginPro 2018 software, employing a nonlinear regression model. Place and Duration of Study: The experiment was carried out in the Federal University of Tocantins, Gurupi – To, Brazil. Soil collection and formal analyzes carried out between January 2023 and August 2023. Methodology: The soil was collected with the aid of a digger, with five subsamples within the useful area of ​​the plot and constituted a composite sample. After collection, samples from the Seed Banks were separated to quantify the seeds present in the soil seed bank, the other half of the sample, the soil was divided into 10 gerbox boxes for each treatment and benches were placed with natural light and kept under irrigation to stimulate germination. Throughout the experiment, temperature and relative humidity were monitored, remaining on average at 26.4°C and 73.5%, respectively. From the pyroligneous liquor obtained, dilutions were made with distilled water at liquor concentrations 0, 1, 2, 3, 4, 5, 10, 15, 20, 25, 50, 75, 100%(v/v) that were used in the treatments. Results: Higher pyroligneous liquor concentrations inhibited seed germination, while lower concentrations had less impact. Conclusion: These findings suggest that pyroligneous liquor can be used to control of weed seed bank.

Spatial–Temporal Dynamics of a Germinable Seed Bank of a Semi-Arid Vegetation in the Brazilian Northeast

Spatial–Temporal Dynamics of a Germinable Seed Bank of a Semi-Arid Vegetation in the Brazilian Northeast

Gardenia (Rubiaceae) seed conservation physiology with emphasis on rare Hawaiian species

Background and aims – Gardenia species are ecologically, culturally, and economically significant but the three native species of Gardenia in Hawai‘i are assessed as Critically Endangered. Seed banking is the most cost effective and efficient means of conserving plant material ex situ. To better understand the conservation physiology of Hawaiian and South Pacific Gardenia spp. and support their conservation, we asked 1) How do seeds respond to different temperatures and light and dark regimes? 2) What class of dormancy, if any, do seeds exhibit? 3) How does seed germinability respond over time in a seed bank? and 4) What is the conservation status and level of ex situ representation of Gardenia globally? Material and methods – To answer these questions, we used 19 accessions of fresh seeds and seeds stored for varying periods of time in the National Tropical Botanical Garden’s Conservation Seed Bank and Laboratory of Hawaiian (G. brighamii, G. remyi), New Caledonian (G. aubryi, G. oudiepe), and Tahitian (G. taitensis) species. Seeds were incubated at varying temperatures and in light, and in dark. Key results – We found that (1) seeds of all species tested germinated slowly and only at higher temperatures in the light and dark, (2) seeds have non-deep physiological dormancy, (3) seeds of the Hawaiian species are short lived at conventional seed bank conditions, and (4) only 40% of Gardenia spp. are represented in ex situ facilities, and 66% of the species have not been evaluated for the IUCN Red List. Conclusion – Seeds of Hawaiian Gardenia spp. are short lived in storage. Since seeds germinate in darkness, they are unlikely to form a persistent soil seedbank. Although seeds of all species tested are physiologically dormant, they can be easily propagated from seed at warmer temperatures, giving some hope to the conservation and restoration of the Critically Endangered Hawaiian species. Since our dataset was limited by a lack of continuous viability monitoring, we emphasize the need for initial germination testing and ongoing viability tests to better understand seed longevity. Lastly, we discuss the ecological relevance of our results in the context of the Hawaiian archipelago.

Repossession Through Community Participation: A Study of Vrihi Community Seed Bank in Odisha

Seeds are the building blocks of food security, and their free exchange amongst the farming community has formed the bedrock for maintaining genetic diversity in addition to food security and sovereignty. The appropriation of production, exchange, and marketing of seeds by the corporate over the past decades has altered the agricultural scene in the Global South. Given the conflicting perspectives, mandates, and practices of multiple stakeholders, this article attempts to critically evaluate seed policies in India considering the cultural, economic, and social undertones that characterise them. From the perspective of the sociology of science, this article attempts to trace the shifts in the decline of the ‘rural,’ erosion of national agriculture, policy gaps, and why values matter in India’s development narratives vis-à-vis science and technology solutions. Further, this article investigates, through a case study of Vrihi Community Seed Bank (CSB),1 located in the eastern state of Odisha, how CSBs are progressively being seen as a possible long-term solution to combat the diverse challenges posed by changing agro-climatic conditions, increasing corporatisation, and industrialisation of agricultural and allied practices of food production.

Ex-situ Conservation of Woody Plants within the Framework of the Millennium Seed Bank Partnership in Georgia

Ex-situ Conservation of Woody Plants within the Framework of the Millennium Seed Bank Partnership in Georgia

BOTANICAL GARDEN NAMED AFTER JÓZSEF SZIKURA

Objective is to study and analyse the history of the creation of the József Szikura Botanical Garden, the results of its scientific, educational and environmental work. Materials and methods of the study. The collections of the natural flora plants established by Professor József Szikura in 2011 in the village of Velyki Berehy, located 8 km northeast of the city of Berehove, Zakarpattya region were studied. The main criteria for assessing the plants diversity in the botanical garden were the following: the qualitative and quantitative composition of the collections, their condition, the results of plant propagation, the possibility of repatriating them to natural ecosystems, the effects of research work, and educational activities. The plant compositions were analyzed, and the species composition of the plots was studied. The role of the botanical garden in preserving the gene pool of flora was also assessed by the qualitative and quantitative composition of the long-lived seed bank. The results of the cultivation and acclimatisation of species of the world flora and the Carpathians have been evaluated since 2012. The evaluation of the results, cultivation and acclimatization of species of the world flora and the Carpathians has been carried out since 2012. Scientific novelty. For the first time, the compositional and systematic composition of the József Szikura Botanical Garden was analysed in the context of successful solution of problems related to the conservation of plant diversity in artificially created phytocoenoses of Transcarpathia. Based on the results of the study, an electronic catalogue (EC) of the Bank of long-lived seeds was created for the first time. Conclusions. According to the results of the inventory analysis, it was determined that the area of 0,82 ha is represented by plants of different natural flora, the taxonomic composition of the collection of which includes 89 families, 468 species, 149 varieties and cultivars. The most numerous families in the collection are Amaryllidaceae J.St.-Hil., Iridaceae Juss., Poaceae Barnhart, Caryophyllaceae Juss., Lamiaceae Martinov, Asteraceae Giseke, Cupressaceae Gray. Three Allium L. species and two Iris L. species are listed in the Red Data Book of Ukraine. The collection contains plants listed in the IUCN Red List (Allium - 5 species, Iris - 2 species) and the relict Syringa josikaea J.Jacq. ex Rchb. The analysis of the composition of the Seed Bank showed the following distribution between taxa – 249 species belonging to 47 families. The József Szikura Botanical Garden effectively combines research work on the study and protection of biodiversity, introduction and acclimatisation, reproduction and efficient use of plants, and functioning as an educational regional centre for the dissemination of ecological and ethnographic knowledge, education and upbringing of the population in the traditions of caring for nature and preserving the cultural heritage of the region.

Effect of the Seed Bank on Evolutionary Rescue in Small Populations: Univariate and Multivariate Demogenetic Dynamics.

AbstractUnder global change, the impact of seed banks on evolutionary rescue is uncertain. They buffer plant populations from demographic and genetic stochasticity but extend generation time and can become a reservoir of maladapted alleles. We built analytical and individual-based models to predict the effect of seed banks on the persistence of small annual plant populations facing an abrupt or sustained directional change in uni- or multivariate trait optima. Demogenetic dynamics predict that under most scenarios seed banks increase the lag yet enhance persistence to 200-250 years by absorbing demographic losses. Simulations indicate that the seed bank has a minimal impact on the genetic skew, although we suggest that this result could depend on the fitness component under selection. Our multivariate model reveals that by enlarging and reshaping the G matrix, seed banks can diminish the impact of mutational correlation and even accelerate adaptation under antagonistic pleiotropy relative to populations without a bank. We illustrate how the magnitude of optimum fluctuations, type and degree of optimum change, selection strength, and vital rates are weights that tip the scales determining persistence. Finally, our work highlights that migration from the past is not maladaptative when optimum fluctuations are large enough to create stepping stones to the new optimum.

Axenic Culture and DNA Barcode Identification of Wood Decay Fungi from the Maltese Islands

Wood-decaying fungi are important study subjects for their ecological role as well as for their biotechnological applications. They break down lignin, cellulose, and hemicelluloses using enzymes that modify the chemical structure of these complex macromolecules. Due to their ability to degrade wood, these fungi can create structural damage to wooden structures and to trees, especially those with very low level of fitness. Previous studies on wood decay fungi in the Maltese Islands are limited to records and checklists described by a handful of authors. The aim of this study was to provide a comprehensive description of wood decay fungal diversity in the Maltese Islands including an updated checklist based on DNA barcoding, as well as to establish the first wood-decay fungal culture collection at the Biology Department Seed Bank of the University of Malta. Several surveys were carried out during the rainy season along wooded areas of the Maltese Islands as well as in historical gardens. Isolates were identified using macro- and micro-morphological features, dichotomous keys, as well as molecular data. Basidiomes were recorded growing on 14 different host plant species, 11 axenic cultures have been made and 9 species of wood decay fungi have been conclusively identified by DNA barcoding. The collection of the axenic isolates includes one of Aurificaria cf. euphoria, three of Ganoderma resinaceum sl., two of Laetiporus sulphureus, one of Inonotus sp., one of Inonotus rickii anamorph, one of Inocutis tamaricis, one of Stereum hirsutum, and one of Pleurotus eryngii. However, the mycelium of Coriolopsis gallica, though collected and identified, could not be isolated.

IMPACT OF SOIL STERILIZATION FROM DIFFERENT LOCATIONS, WHEAT SEEDS CLEANING AND THEIR INTERACTIONS ON WEED CONTROL, AND YIELD AND YIELD COMPONENTS

IMPACT OF SOIL STERILIZATION FROM DIFFERENT LOCATIONS, WHEAT SEEDS CLEANING AND THEIR INTERACTIONS ON WEED CONTROL, AND YIELD AND YIELD COMPONENTS

Seeds of latent hope: The figurative entwinement of children, adolescents, and plants in Maja Lunde’s "The Dream of a Tree"

Drawing on theorizations of climate fiction, previous studies of plants in climate fiction (cli-fi) for young adults, perspectives from critical plant studies, and discussions on the symbolism of seeds and trees, this study traces metaphorical relationships between plants and the child- and adolescent characters in Maja Lunde’s latest climate fiction, The Dream of a Tree (Drømmen om et tre, 2022). The novel is the last volume in Lunde’s “climate quartet”, where she, for the first time in her series, employs a young adult protagonist. The plot revolves around a group of children, stranded on the archipelago of Svalbard that hosts the Global Seed Vault. The study aims to show how the child and adolescent characters in Lunde’s climate fiction are embedded in metaphorical patterns associating them with growth and hope in ways that serve to move Lunde’s climate quartet from a dystopian towards a more utopian resolution.

Planting The Seed

Cultural preservation is an evolving phenomenon that has historically been undertaken through the written or oral passage of knowledge from one generation to the next. Some archives emerge so individuals can understand their social, cultural, and personal histories, while others emerge to preserve non-human-related specimens to prepare for worst-case scenarios. This paper discusses the notion of the “doomsday” archive and connects it to concepts of archival practice by exploring the history and efficacy of the Svalbard Global Seed Vault and the various ways humans have used archival principles to mitigate harm in the face of global catastrophes.

Towards a standardised orchid germination protocol: determining the optimal duration of chemical scarification for orchid seeds by means of viability and permeability staining

Complex nutrient media are used for the germination of orchids in the laboratory. These substrates are also suitable for the growth of microbes and thus the sterilization of both the medium and the seeds prior to sowing is mandatory. The surface disinfection of orchid seeds with chemical substances eliminates possible infections and enhances germination in several cases, by chemically scarifying their seed coats. However, long durations of chemical treatments may result in viability loss, and consequently, precisely determining the optimal treatment duration is essential for developing effective germination protocols. In this study, the double staining technique with Tetrazolium Chloride and Trypan Blue is tested as a proxy method to determine the optimal chemical treatment duration for 10 orchid taxa of Greece. Various durations of chemical treatment with 5% Ca(OCl)2 were carried out on independent seed samples which were subsequently tested, pairwise, for both germination and viability. The results in the corresponding experiments are extraordinarily similar and we conclude that the double viability staining is a quick and accurate technique in determining the permeability and optimal duration for chemical scarification prior to germination experiments. The storability potential of the taxa studied is discussed in comparison with previous data of the NKUA Seed Bank.

The Trypsin Inhibitory Activity of Vigna unguiculata ssp. Sesquipedalis (Hawari Mae) Seeds Grown in Sri Lanka was Evaluated

Aims: This study aimed to screen the entire seed sample of Vigna unguiculata ssp sesquipedalis (Hawari mae) for serine protease inhibitory activity. Additionally, the study explored the impact of various factors such as temperature, pH, metal ions, detergent, oxidizing and reducing agents on the inhibitory activity. Methodology: A batch of Hawari Mae seeds was obtained from the Plant Genetic Resources Center in Sri Lanka. A concentration gradient of aqueous seed extracts was tested for Serine Inhibitory Activity (SIA). To carry out the SIA assay, seed extracts were mixed with trypsin in phosphoric acid buffer (pH 7.6) and casein was added as the substrate. The samples were then incubated at 37°C and trichloroacetic acid was used to stop the reaction. The supernatants were checked for absorbance at 280 nm and the percentage of serine inhibitory activity (SIA%) was calculated. All experiments were conducted three times to ensure accuracy. The inhibitory activities were tested under various conditions, including different temperatures, pH levels, metal ions, detergents, and oxidizing and reducing agents. Results: The crude extract containing 10% of the substance showed the highest level of trypsin inhibitory activity at 96.03±0.005%. This particular extract was selected for further analysis. The study revealed that the enzyme inhibition activity was highest at a temperature of 37°C (95.42±0.006%) and a pH of 7.6 (95.71±0.003%). It was observed that all tested metal ions, except Cu2+, significantly reduced (P<0.05) the trypsin inhibitory activity in Hawari mae. The presence of the detergent Triton X-100 did not significantly affect (P>0.05) the trypsin inhibitory activity of Hawari mae. However, the presence of DMSO and dithiothreitol significantly (P<0.05) reduced its activity. Conclusion: Significant trypsin inhibitory activity was observed in the seed extract of Hawari mae. Further studies on the effects of various physio-chemical parameters can aid in the purification and isolation of trypsin inhibitors.

Short-Interval, High-Severity Wildfire Depletes Diversity of Both Extant Vegetation and Soil Seed Banks in Fire-Tolerant Eucalypt Forests

Many plant species are well-adapted to historical fire regimes. An increase in the severity, frequency, and extent of wildfires could compromise the regenerative capacity of species, resulting in permanent shifts in plant diversity. We surveyed extant vegetation and soil seed banks across two forest types with contrasting historical fire regimes—Shrubby Dry Forest (fire return interval: 10–20 years) and Sub-Alpine Woodland (50–100 years). Over the past 20 years, both forests have been subject to repeated, high-severity wildfires at intervals significantly shorter than their historical return intervals. We examined the soil seed bank response to fire-cued germination, and whether the plant diversity in soil seed banks and extant vegetation demonstrated similar responses to short-interval, high-severity wildfires. The soil seed bank demonstrated a positive response to heat in combination with smoke, and for the Sub-Alpine Woodland, this was limited to sites more frequently burnt by fire. With an increase in fire frequency, there was a decline in species richness and Shannon’s Diversity and a shift in species composition in both extant vegetation and the soil seed bank. The fire frequency effects on the relative richness of trait associations were restricted to the Shrubby Dry Forest, and included an increase in short-lived obligate seeders, wind-dispersed species, and ant-dispersed shrubs in burnt relative to long unburnt sites in both extant vegetation and the soil seed bank. Graminoids were the most abundant component of the soil seed banks of Sub-Alpine Woodlands, and this increased with more frequent fire, with a similar trend (p = 0.06) in extant vegetation. Clear shifts in plant diversity in both soil seed banks and extant vegetation in forest types with contrasting historical fire regimes suggest that emerging fire regimes are pushing ecosystems beyond their historical range of variability, including potentially more flammable states and a decline in the buffering capacity of soil seed banks.