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Seed-based restoration in dryland environments is commonly limited by low and sporadic rainfall, extreme temperatures, and degraded soils. These challenges are exacerbated in dryland mine restoration sites where species are seeded onto mine waste substrates due to limited availability of topsoil. Native grasses are focal dryland and mine restoration species, though the ability to deliver seeds to targeted sites presents further constraints to seed-based restoration due to complex seed morphology and site attributes. Seed enhancement technologies (SETs) may help to mitigate environmental stressors and improving seed handling. In this study, SETs which promote seedling recruitment and/or address edaphic challenges while also improving seed morphology and handling were tested in four Australian native grasses (Cymbopogon ambiguus, C. obtectus, Eulalia aurea, and Eriachne obtusa). Flash flaming or acid digestion (depending on species), extruded seed pellets with or without the addition of topsoil, and flaming or acid digestion used in combination with extruded pellets (with or without topsoil) were evaluated on topsoil and mine waste substrates. Material treated with either flash flaming or acid digestion tended to produce similar maximum emergence (week 3), final emergence (week 14), and above-ground biomass (week 14) on both topsoil and mine waste when compared to the un-enhanced ('control') treatment. Extruded pellets enhanced emergence (maximum and final) on both soil types, though had no effect on biomass. Extruded pellets containing topsoil and/or when used in combination with flash flamed or acid digested florets, provided the most significant benefits to seedling emergence, particularly on mine waste soil. However, SETs were unable to mitigate the detrimental effects of mine waste substrates on seedling biomass. This study shows promise for improving seed-based restoration in post-mine and dryland environments using SETs, though also highlights potential limitations and the importance of understanding long-term (i.e., beyond emergence) plant recruitment outcomes in SET applications. [ABSTRACT FROM AUTHOR]

Tree establishment following severe or stand-replacing disturbance is critical for achieving U.S. climate change mitigation goals and for maintaining the co-benefits of intact forest ecosystems. In many contexts, natural post-fire tree regeneration is sufficient to maintain forest cover and associated ecosystem services, but increasingly the pattern and scale of disturbance exceeds ecological thresholds and active reforestation may be warranted. Our capacity to plant trees, however, is not keeping pace with reforestation needs. This shortfall is uniquely apparent in the western U.S., where wildfire size and severity have increased in recent decades and long-term divestment in the reforestation supply chain has limited our ability to respond to existing needs. Here we present an analysis of key facets of both the supply and demand side of reforestation in the western U.S. and address six questions: (1) What is the current backlog of potential reforestation needs driven by high-severity wildfire?; (2) How will increasing wildfire activity through the end of the century affect potential reforestation needs?; (3) What is our capacity to meet current and future reforestation needs?; (4) How can we scale the reforestation supply chain to meet current and future demands?; (5) What approaches to reforestation can promote forest resilience to climate change and wildfire?; and (6) Where are opportunities emerging from recent policy initiatives, innovative public-private partnerships, and natural capital markets for scaling reforestation? Between 1984 and 2000, annual tree planting capacity met post-fire needs but cumulatively over the last two decades (2000 to 2021) it has fallen short of fire-driven needs by an estimated 1.5 million ha (ca. 3.8 million ac). We anticipate this gap will increase 2 to 3 fold by 2050. Scaling up reforestation efforts to close this gap will require increased investment across all facets of the reforestation supply chain, public-private partnerships, and novel approaches to reforestation that increase the resilience of western forests to drought and wildfire. We highlight emerging opportunities from recent policy initiatives and conservation finance for expanding reforestation efforts. [ABSTRACT FROM AUTHOR]

As larger tracts of land experience degradation, seed‐based restoration (SBR) will be a primary tool to reestablish vegetation and ecosystem function. SBR has advanced in terms of technical and technological approaches, yet plant recruitment remains a major barrier in some systems, notably drylands. There is an unmet opportunity to test science‐based approaches to seed mix design and application, based not only on diversity or local provenance, but on the unique recruitment strategies of species. We lay out a framework that uses a quantitative representation of species' recruitment niches to match them to targeted goals (e.g. drought or invasion resistance) and methods (e.g. precision tools and technologies) in SBR. We first describe how to quantify the recruitment niche with seed and seedling traits tied to observed recruitment responses to environmental factors. We then show how a quantified recruitment niche framework can serve as the foundation to address three major restoration challenges: (1) designing forward‐looking seed mixes that increase resilience to future climate and disturbance, (2) accounting for natural recovery in SBR planning, and (3) applying precision seeding practices to maximize restoration success. Finally, we demonstrate these ideas with existing data and discuss key challenges to adoption in SBR practice. While the ideas in this framework are based in ecological theory, they will require substantial testing and refinement by scientists engaged in SBR efforts. If this framework is integrated into research agendas, we believe it has the potential to unify and advance diverse elements of seed‐based restoration ecology and improve restoration outcomes. [ABSTRACT FROM AUTHOR]

Pre‐emergent herbicides, commonly employed for managing invasive annual plants, often fail to meet restoration targets due to the absence of remnant perennial plants, which leaves sites vulnerable to re‐invasion and hinders effective control of annual grasses. Combining an herbicide treatment with seeding is therefore desirable, but seeded plants can also be negatively impacted by pre‐emergent herbicides. Herbicide protection (HP) seed technologies use activated carbon to adsorb herbicide near seeds and have shown promise for allowing simultaneous deployment of herbicide and seed, but recent research recommends numerous additional refinements be tested. We addressed some of these recommendations through one laboratory and a field trial replicated at multiple sites to explore whether commercially produced, single‐seed HP coatings with two different rates of activated carbon can prevent herbicide‐related damage to two perennial bunchgrasses native to the western United States. We also investigated how these coated prototypes compare in performance to the multi‐seed extruded herbicide protection pellets (HPPs) tested in prior research. In the laboratory, neither coating treatment reduced total emergence, emergence rate, survival, or biomass in the absence of herbicide. In the presence of herbicide, both provided several‐fold higher survival and aboveground biomass compared to untreated bare seed, but this represented incomplete protection from herbicide. In field trials where conditions were harsher than the laboratory, we found no evidence of HP from any treatment, and HPPs reduced seedling count for one species. We conclude that the tested HP coating prototype is an improvement over HPPs but requires additional refinements and testing. [ABSTRACT FROM AUTHOR]