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Restoration of degraded drylands is urgently needed to mitigate climate change, reverse desertification and secure livelihoods for the two billion people who live in these areas. Bold global targets have been set for dryland restoration to restore millions of hectares of degraded land. These targets have been questioned as overly ambitious, but without a global evaluation of successes and failures it is impossible to gauge feasibility. Here we examine restoration seeding outcomes across 174 sites on six continents, encompassing 594,065 observations of 671 plant species. Our findings suggest reasons for optimism. Seeding had a positive impact on species presence: in almost a third of all treatments, 100% of species seeded were growing at first monitoring. However, dryland restoration is risky: 17% of projects failed, with no establishment of any seeded species, and consistent declines were found in seeded species as projects matured. Across projects, higher seeding rates and larger seed sizes resulted in a greater probability of recruitment, with further influences on species success including site aridity, taxonomic identity and species life form. Our findings suggest that investigations examining these predictive factors will yield more effective and informed restoration decision-making.
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Articles
https://doi.org/10.1038/s41559-021-01510-3
A full list of affiliations appears at the end of the paper.
Restoration ecology is rapidly advancing in response to the
ever-expanding global decline in ecosystem integrity and its
associated socio-economic repercussions14. Nowhere are
these dynamics more evident than in drylands, which help sustain
39% of the world’s human population5 but remain some of the most
difficult areas to restore6,7. Restoration of degraded dryland ecosys-
tems is frequently constrained by low and variable precipitation,
extreme temperatures, relatively low soil fertility, seed quality and
availability and a prevalence of invasive species811. As a result, suc-
cessful establishment of seeded species in dryland restoration proj-
ects may be as low as 1%12,13. Despite these challenges, only a small
fraction of terrestrial ecology (6%)14 and restoration studies (<5%)15
are conducted in drylands.
Dryland ecosystems are ecologically distinct16,17, increasing in
global extent under shifting climates1820 and have been recognized
as degraded in over 50% of their range21. Depending on the sever-
ity of degradation, vegetation recovery of depleted and denuded
dryland landscapes through natural succession processes is very
slow, if not impossible22. Passive restoration methods (for example
reducing livestock and wildlife grazing) are often ineffective alone,
as degraded dryland environments can show stability and resilience
in undesired states11. Resource-intensive methods such as seedling
Drivers of seedling establishment success in
dryland restoration efforts
Nancy Shackelford 1,2,71 ✉ , Gustavo B. Paterno 3,4,71, Daniel E. Winkler5, Todd E. Erickson6,7,
Elizabeth A. Leger8, Lauren N. Svejcar9, Martin F. Breed 10, Akasha M. Faist11, Peter A. Harrison 12,
Michael F. Curran13, Qinfeng Guo 14, Anita Kirmer 15, Darin J. Law16, Kevin Z. Mganga17,
Seth M. Munson 18, Lauren M. Porensky19, R. Emiliano Quiroga20,21, Péter Török 22,
Claire E. Wainwright23, Ali Abdullahi24, Matt A. Bahm25, Elizabeth A. Ballenger26, Nichole Barger2,
Owen W. Baughman27, Carina Becker 28, Manuel Esteban Lucas-Borja29, Chad S. Boyd9,
Carla M. Burton30, Philip J. Burton 30, Eman Calleja31, Peter J. Carrick32, Alex Caruana 31,
Charlie D. Clements33, Kirk W. Davies9, Balázs Deák 34, Jessica Drake35, Sandra Dullau 15,
Joshua Eldridge36, Erin Espeland37, Hannah L. Farrell18, Stephen E. Fick5, Magda Garbowski38,
Enrique G. de la Riva39, Peter J. Golos 7, Penelope A. Grey40, Barry Heydenrych41,
Patricia M. Holmes 42, Jeremy J. James43, Jayne Jonas-Bratten 44, Réka Kiss34, Andrea T. Kramer45,
Julie E. Larson2, Juan Lorite 46,47, C. Ellery Mayence48, Luis Merino-Martín 49, Tamás Miglécz50,
Suanne Jane Milton 51,52, Thomas A. Monaco53, Arlee M. Montalvo54, Jose A. Navarro-Cano55,
Mark W. Paschke56, Pablo Luis Peri57, Monica L. Pokorny58, Matthew J. Rinella59, Nelmarie Saayman60,
Merilynn C. Schantz61, Tina Parkhurst62, Eric W. Seabloom 63, Katharine L. Stuble64,
Shauna M. Uselman65, Orsolya Valkó 34, Kari Veblen 66, Scott Wilson67, Megan Wong68,
Zhiwei Xu 69 and Katharine L. Suding 2,70
Restoration of degraded drylands is urgently needed to mitigate climate change, reverse desertification and secure livelihoods
for the two billion people who live in these areas. Bold global targets have been set for dryland restoration to restore millions
of hectares of degraded land. These targets have been questioned as overly ambitious, but without a global evaluation of suc-
cesses and failures it is impossible to gauge feasibility. Here we examine restoration seeding outcomes across 174 sites on six
continents, encompassing 594,065 observations of 671 plant species. Our findings suggest reasons for optimism. Seeding had
a positive impact on species presence: in almost a third of all treatments, 100% of species seeded were growing at first monitor-
ing. However, dryland restoration is risky: 17% of projects failed, with no establishment of any seeded species, and consistent
declines were found in seeded species as projects matured. Across projects, higher seeding rates and larger seed sizes resulted
in a greater probability of recruitment, with further influences on species success including site aridity, taxonomic identity
and species life form. Our findings suggest that investigations examining these predictive factors will yield more effective and
informed restoration decision-making.
NATURE ECOLOGY & EVOLUTION | VOL 5 | SEPTEMBER 2021 | 1283–1290 | www.nature.com/natecolevol 1283
Content courtesy of Springer Nature, terms of use apply. Rights reserved
... The use of suitable strategies for dry forest restoration is of primary concern due to the high levels of degradation affecting these ecosystems in the world (Vieira and Scariot 2006;Svejcar and Kildisheva 2017;Hallett and Omar, 2020). In fact, successful establishment of seeded species in dry lands restoration projects may be as low as 1 % due to severe environmental factors, such as scarce and variable precipitation, extreme temperatures and relatively low soil fertility (Shackelford et al. 2021). Therefore, using nurse plants for seedling establishment could be particularly useful in highly disturbed arid environments (Domínguez et al., 2015;Torres et al. 2021). ...
... Drylands occupy a large proportion of land in the world (41 %), with most of them being degraded in over 50 % of their range, and with very low or no resilience (Shackelford et al. 2021). However, published works on restoration in dry forest are still scarce, with most studies being concentrated in the northern hemisphere, especially in western North America, and in tropical rain forests (Vieira and Scariot 2006;Svejcar and Kildisheva 2017;Hallett and Omar, 2020;Shackelford et al. 2021). ...
... Drylands occupy a large proportion of land in the world (41 %), with most of them being degraded in over 50 % of their range, and with very low or no resilience (Shackelford et al. 2021). However, published works on restoration in dry forest are still scarce, with most studies being concentrated in the northern hemisphere, especially in western North America, and in tropical rain forests (Vieira and Scariot 2006;Svejcar and Kildisheva 2017;Hallett and Omar, 2020;Shackelford et al. 2021). In South America, in the Arid Chaco region of Argentina, the driest and least productive portion of the Gran Chaco, agricultural and forestry exploitation has generated profound changes in plant communities, with the consequent degradation of vast areas (Zak et al. 2008;Hoyos et al. 2013;Cabido et al. 2018). ...
Article
In degraded dry environments, a promising restoration strategy involves nurse plants and their microsites, which facilitate species recruitment. Different nurse plant species might provide different microclimatic and soil conditions under their canopy as well as diverse herbivory protection strategies. Seed provenance of target species is also relevant to restoration success. We evaluated the effectiveness of two native woody species (Parkinsonia praecox and Larrea divaricata) as nurse plants for Prosopis flexuosa establishment to be used in restoration programs in semiarid Chaco forests of central Argentina. We conducted a field experiment in a degraded site to analyze microclimatic and soil characteristics under the canopy of the nurse species and in bare soil. In these microsites we planted 240 P. flexuosa saplings to evaluate their performance during two years, including local and non-local provenances. Both nurse species were safer sites for recruitment than bare soil, because under their canopies microclimatic characteristics were ameliorated and soil nutrient availability was increased, with the best sapling performance being under P. praecox crown. Of the total plants that survived (42%), most of them did so under the nurses (74%). Height of P. flexuosa saplings decreased regarding initial height, in the three microsites. Herbivory greatly limited sapling establishment success in bare soil; therefore, both nurses would have an important role in providing shelter. P. flexuosa performance was not influenced by provenance. Including P. praecox and L. divaricata as nurse plants in restoration strategies would promote the use of established vegetation in recovering the semi-arid Chaco forest.
... Planting nursery-grown seedlings is common in revegetation, but is relatively inefficient and limited to small scales (<100 ha) or to species that occur in low densities (e.g. trees and shrubs) (Leverkus et al. 2021;Shackelford et al. 2021;Svejcar et al. 2021). Direct-seeding provides a more time and cost-effective technique for revegetation over large scales (100s-1000s of ha) and for species that occur in high densities (e.g. ...
... Direct-seeding provides a more time and cost-effective technique for revegetation over large scales (100s-1000s of ha) and for species that occur in high densities (e.g. grasses and herbs) (Leverkus et al. 2021;Shackelford et al. 2021;Svejcar et al. 2021). ...
... Abiotic barriers include heavily modified environments, such as where agricultural or mining activities have degraded soils (e.g. topsoil removal) ), or where climate change has altered rainfall (Shackelford et al. 2021). Dispersal challenges (i.e. ...
Article
Almost 1 billion ha of land have been pledged for restoration globally under the UN Decade on Ecosystem Restoration. Seed‐based restoration will be essential to achieve native revegetation targets in a timely and effective manner. However, problematic seed germination, seeding environments, and seed handling can limit our ability to use native seeds in revegetation. Seed enhancement technologies (SETs) are post‐harvest seed treatments which may improve seed performance and handling, thereby optimizing seed use efficiency and success in restoration. We highlight SETs as a restoration tool accessible to anyone and which can also be used to deliver seed‐based restoration at scale. If SETs are to rise to the challenge of restoration targets in the coming decade, improving native seed supply, research efforts, knowledge and data sharing, and collaboration and funding will be essential. These actions are discussed within a roadmap for advancing SETs in the UN Decade on Ecosystem Restoration. This article is protected by copyright. All rights reserved.
... Congenital advantages of xerophytes in the study of seed DT Dryland ecosystems are ecologically distinct, increasing in global extent under shifting climates and have been recognized as degraded in over 50% of their range (Shackelford et al., 2021). Various ecosystem assessments have indicated this is a threatened habitat and intervention is needed (Louhaichi et al., 2014;Peŕez et al., 2019;Miguel et al., 2020;Shackelford et al., 2021). ...
... Congenital advantages of xerophytes in the study of seed DT Dryland ecosystems are ecologically distinct, increasing in global extent under shifting climates and have been recognized as degraded in over 50% of their range (Shackelford et al., 2021). Various ecosystem assessments have indicated this is a threatened habitat and intervention is needed (Louhaichi et al., 2014;Peŕez et al., 2019;Miguel et al., 2020;Shackelford et al., 2021). For this, it is best to use native species, particularly shrubby xerophytes. ...
Article
Full-text available
Germplasm conservation strongly depends on the desiccation tolerance (DT) of seeds. Xerophytic seeds have strong desiccation resistance, which makes them excellent models to study DT. Although some experimental strategies have been applied previously, most methods are difficult to apply to xerophytic seeds. In this review, we attempted to synthesize current strategies for the study of seed DT and provide an in-depth look at Caragana korshinskii as an example. First, we analyze congenital advantages of xerophytes in the study of seed DT. Second, we summarize several strategies used to study DT and illustrate a suitable strategy for xerophytic species. Then, based on our previous studies work with C. korshinskii , a feasible technical strategy for DT re-establishment is provided and we provide illustrate some special molecular mechanisms seen in xerophytic seeds. Finally, several steps to unveil the DT mechanism of xerophytic seeds are suggested, and three scientific questions that the field should consider are listed. We hope to optimize and utilize this strategy for more xerophytic species to more systematically decipher the physiological and molecular processes of seed DT and provide more candidate genes for molecular breeding.
... exclusion of grazing) do not result in sufficient return of plant species, then re-introduction of plants is needed, often requiring large quantities of seeds of wild species (Merritt and Dixon, 2011). Seeds can be employed for planting seedlings via nursery production and for broadcast or direct seeding, depending on the species and context (Commander et al., 2013;Shackelford et al., 2021). But sourcing vast quantities of seeds from wild populations has significant ecological and financial consequences and implementing large-scale, seed-based restoration projects compels practitioners to use seeds as efficiently as possible (Gibson-Roy et al., 2021). ...
... Seedling recruitment is one of the most vulnerable stages of the plant lifecycle, and poor germination and seedling establishment frequently hinder ecological restoration, particularly in arid environments and other ecosystems with marked dry seasons (Palma and Laurance, 2015;Lewandrowski et al., 2017;Merino-Martín et al., 2017;Shackelford et al., 2021). Restoration trajectories may be set during the earliest phases of plant recruitment (Fraaije et al., 2015), and patterns of early vegetation community assembly from sown seeds can endure long into the future (Hoelzle et al., 2012;Groves et al., 2020). ...
Article
Full-text available
Seeds are a primary source for generating plants for large-scale restoration and understanding the requirements for seed germination and establishment is fundamental to ecological restoration. Seed germination traits are central to defining the germination niche and identifying traits that may limit seedling establishment provides insights into how seeds may interact with the abiotic environment and the soil substrates specific to each restoration site and informs seed management practices. In this paper we review seed trait data derived from research to improve restoration practice across diverse ecosystems within Western Australia. We compile and evaluate seed trait data for up to 300 seed collections of 287 species that are used in restoration programmes to identify species, lifeform, and region-specific variation in seed dormancy, maximum germination, germination speed, base water potential, and germination niche breadth. Through a synthesis of this data, we outline our ecologically-guided approach to identifying key seed traits that support plant regeneration to improve the success of seed-based restoration across the biodiverse Western Australian landscape.
... Restoration of arid and semiarid lands is a global priority but is constrained by low success rates (Shackelford et al. 2021). Factors contributing to the failure of dryland seeding are complex and heterogeneously distributed in space and time (Whisenant 1999;Boyd & Davies 2012;Hardegree et al. 2016;Kildisheva et al. 2016;Copeland et al. 2021), and arise from the natural complexities of dryland ecology itself (Boyd & Svejcar 2009;Winkler et al. 2018;Hoover et al. 2020), sociopolitical constraints (Cortina-Segarra et al. 2021), as well as from the specific methods and approaches used (Ott et al. 2017;Havrilla et al. 2020). ...
... Factors contributing to the failure of dryland seeding are complex and heterogeneously distributed in space and time (Whisenant 1999;Boyd & Davies 2012;Hardegree et al. 2016;Kildisheva et al. 2016;Copeland et al. 2021), and arise from the natural complexities of dryland ecology itself (Boyd & Svejcar 2009;Winkler et al. 2018;Hoover et al. 2020), sociopolitical constraints (Cortina-Segarra et al. 2021), as well as from the specific methods and approaches used (Ott et al. 2017;Havrilla et al. 2020). Natural factors closely linked with seed-based restoration success can include weather and climate variation (Hagger et al. 2018;Shriver et al. 2018;James et al. 2019;Shackelford et al. 2021), competition with invasive species (Humphrey & Schupp 2004;Eiswerth et al. 2009;Mangla et al. 2011), pathogens and predation (Barber a et al. 2006;Suazo Author contributions: JDK, CSB, MM, TJS conceived, designed, and performed the research; OWB, JDK analyzed the data and drafted the manuscript; all authors provided edits and comments and participated in the revision of the manuscript. Gornish et al. 2015), and physically prohibitive soil characteristics (Madsen et al. 2012;Ritchie et al. 2020). ...
Article
Full-text available
Efforts to restore semi‐arid wildlands in the western United States predominantly use fall seeding. Fall conditions are more amenable to seeding, and successfully over‐wintered seeds or plants are poised to take full advantage of spring moisture. However, over‐winter mortality can be a barrier to seeding success. One solution to avoid winter mortality without sacrificing the benefits of fall seeding is to delay germination of fall‐sown seeds. At six northern Great Basin field sites over three planting years (18 trials), we tested whether a hydrophobic seed coating reliably delayed germination and increased seedling establishment of a native bunchgrass. Despite considerable variation among sites and years, seed treatment successfully reduced pre‐winter germination by 84% compared to untreated, but also consistently reduced final germination by 23%. Still, treatment resulted in an average of 2.1‐fold higher emerged seedling density in seven trials, six of which were among the eight trials where more than 50% of untreated seeds germinated pre‐winter. Emergence was greater for untreated seed in five trials, all of them in the same year, and all but one of them with below‐average total germination. Our treatment consistently reduced pre‐winter germination, but only improved emergence when pre‐winter germination of untreated seeds was high. Continued research is merited with germination‐delaying treatments and to experimentally define – and develop models that predict – winter‐related mortality barriers. We also suggest future exploration of bet hedging strategies that mix treated and untreated seeds where fall seeding is required and significant but variable risk of over‐winter seedling mortality exists. This article is protected by copyright. All rights reserved.
... Speculatively, this could reflect a weaker initial environmental filter on colonization that becomes more apparent through time, perhaps reflecting growing dominance of more resource-acquisitive species. Greater habitat connectivity and dispersal could therefore dampen losses under nutrient addition, particularly because grasslands are capable of supporting greater diversity than their steady-state richness suggests (Foster & Tilman, 2003;Shackelford et al., 2021). Accordingly, dispersal limitation may enhance declines in both absolute and functional richness. ...
Article
(1) Declines in grassland diversity in response to nutrient addition are a general consequence of global change. This decline in species richness may be driven by multiple underlying processes operating at different timescales. Nutrient addition can reduce diversity by enhancing the rate of local extinction via competitive exclusion, or by reducing the rate of colonization by constraining the pool of species able to colonize under new conditions. Partitioning net change into extinction and colonization rates will better delineate the long‐term effect of global change in grasslands. (2) We synthesized changes in richness in response to experimental fertilization with nitrogen, phosphorus and potassium with micronutrients across 30 grasslands. We quantified changes in local richness, colonization, and extinction over 8‐10 years of nutrient addition, and compared these rates against control conditions to isolate the effect of nutrient addition from background dynamics. (3) Total richness at steady state in the control plots was the sum of equal, relatively high rates of local colonization and extinction. On aggregate, 30‐35% of initial species were lost and the same proportion of new species were gained at least once over a decade. Absolute turnover increased with site‐level richness, but was proportionately greater at lower richness sites relative to starting richness. Loss of total richness with nutrient addition, especially N in combination with P or K, was driven by enhanced rates of extinction with a smaller contribution from reduced colonization. Enhanced extinction and reduced colonization were disproportionately among native species, perennials, and forbs. Reduced colonization plateaued after the first few (< 5) years after nutrient addition, while enhanced extinction continued throughout the first decade. (4) Synthesis. Our results indicate a high rate of colonizations and extinctions underlying the richness of ambient communities, and that nutrient enhancement drives overall declines in diversity primarily by exclusion of previously established species. Moreover, enhanced extinction continues over long time scales, suggesting continuous, long‐term community responses and a need for long‐term study to fully realize the extinction impact of increased nutrients on grassland composition.
... For example, in prairie seed mixes if the ratio of grasses to forbs is too high, it can impede the establishment of individual forb species (Dickson and Busby, 2009;Grman et al., 2015). Some species may benefit from repeated seeding (Sluis et al., 2018) and/or a higher seeding rate (Grman et al., 2015;Shackelford et al., 2021). For species that are difficult to establish from seed, planting plugs is often recommended (Gallagher and Wagenius, 2016), but some species are more likely to establish and persist at a site when planted from seeds (St. ...
Article
Full-text available
The U.N. Decade on Ecosystem Restoration aims to accelerate actions to prevent, halt, and reverse the degradation of ecosystems, and re-establish ecosystem functioning and species diversity. The practice of ecological restoration has made great progress in recent decades, as has recognition of the importance of species diversity to maintaining the long-term stability and functioning of restored ecosystems. Restorations may also focus on specific species to fulfill needed functions, such as supporting dependent wildlife or mitigating extinction risk. Yet even in the most carefully planned and managed restoration, target species may fail to germinate, establish, or persist. To support the successful reintroduction of ecologically and culturally important plant species with an emphasis on temperate grasslands, we developed a tool to diagnose common causes of missing species, focusing on four major categories of filters, or factors: genetic, biotic, abiotic, and planning & land management. Through a review of the scientific literature, we propose a series of diagnostic tests to identify potential causes of failure to restore target species, and treatments that could improve future outcomes. This practical diagnostic tool is meant to strengthen collaboration between restoration practitioners and researchers on diagnosing and treating causes of missing species in order to effectively restore them.
... Poor seedling emergence is a common bottleneck in native seedbased restoration (Shackelford et al. 2021). Although options exist to overcome this bottleneck (e.g. ...
Article
Extruded pellets containing activated carbon (AC) can be used to sow native seeds whilst simultaneously applying herbicide to control invasive species. Incorporating AC in pellets has been demonstrated to protect native seeds, however; there may be unintended detrimental impacts to seedling emergence. We aimed to optimise seed position within pellets to maximise emergence and survival of the perennial shrub Jacksonia furcellata. Seeds were positioned at 2 mm (top), 6 mm (middle) and 12 mm (bottom) within pellets (with or without AC), sown on or below the soil surface, and compared to non‐pelleted seeds sown under the soil surface in the equivalent positions (2, 6 and 12 mm depth). Trays were treated with a pre‐emergent herbicide (Simazine) or left unsprayed. Emergence (without herbicide) was significantly higher from seeds positioned at the bottom of pellets without AC sown on the soil surface (70%), compared to non‐pelleted seeds sown at the bottom (12 mm below the soil surface; 57%). However, emergence was inhibited when seeds were positioned in the middle (6 mm) of pellets with AC (32%). When treated with Simazine, survival was highest from seeds positioned at the bottom of pellets with AC (60%), compared to pellets without AC (15%) and non‐pelleted seeds sown at the bottom (12 mm below the soil surface; 15%). Jacksonia furcellata seeds positioned at the bottom of pellets, sown on the soil surface, shows promise to minimise negative impacts to emergence, and maximise herbicide protection. Further testing with additional species is required to refine pellet production (e.g., recipe, extrusion and shape) for optimal emergence. This article is protected by copyright. All rights reserved.
... Incomplete recovery of biodiversity and ecosystem functions on restored old fields may be due to abiotic and biotic constraints to recovery, such as depleted soil chemical and biophysical functions, altered edaphic properties, and competition mechanism of native and invasive plant species (Shackelford et al., 2021) (Flinn & Marks, 2007;Piché & Kelting, 2015;Standish et al., 2006). For example, compacted soils and depleted soil carbon concentrations limit key ecosystem functions such as water infiltration and water storage capacity, therefore reducing ecosystem productivity (Franzluebbers, 2002). ...
Article
Full-text available
Ecological restoration of former agricultural land can improve soil conditions, recover native vegetation, and provide fauna habitat. However, restoration benefits are often associated with time lags, as many attributes, such as leaf litter and coarse woody debris, need time to accumulate. Here, we experimentally tested whether adding mulch and logs to restoration sites in semi-arid Western Australia can accelerate restoration benefits. All sites had been cropped and then planted with native trees and shrubs (i.e., Eucalyptus, Melaleuca, and Acacia spp.) 10 years prior to our experiment, to re-establish the original temperate eucalypt woodland vegetation community. We used a Multi-site Before-After-Control-Impact (MBACI) design to test the effects on 30 abiotic and biotic response variables over a period of 2 years. Of the 30 response variables, a significant effect was found for just four variables: volumetric water content, decomposition, native herbaceous species cover and species richness of disturbance specialist ants. Mulch addition had a positive effect on soil moisture when compared to controls but suppressed growth of native (but not exotic) herbaceous plants. On plots with log additions, decomposition rates decreased, and species richness of disturbance specialist ants increased. However, we found no effect on total species richness and abundance of other ant species groups. The benefit of mulch to soil moisture was offset by its disbenefit to native herbs in our study. Given time, logs may also provide habitat for ant species that prefer concealed habitats. Indeed, benefits to other soil biophysical properties, vegetation, and ant fauna may require longer time frames to be detected. Further research is needed to determine whether the type, quantity, and context of mulch and log additions may improve their utility for old field restoration and whether effects on native herbs are correlated with idiosyncratic climatic conditions.
... If insects are, in fact, moving among well pads, they may be delivering benefits to plants in the reference areas by increasing genetic diversity through cross-pollination and may be providing other ecosystem services such as comminution of organic matter, nutrient cycling and acting as a food source for other birds and animals (Grodsky et al. 2018). Although vegetation communities were different between reclaimed sites and reference areas, with reference areas exhibiting vegetation communities closer to climax stages of succession, it is important to understand ecosystem dynamics on early seral reclamation sites because land restoration in arid environments is challenging (Shackelford et al. 2021) and sagebrush reestablishment on disturbed sites may take decades (Monroe et al. 2020). ...
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Insects are critical components of terrestrial ecosystems and are often considered ecosystem engineers. Due to the vast amount of ecosystem services they provide, because statistically valid samples can be captured in short durations, and because they respond rapidly to environmental change, insects have been used as indicators of restoration success and ecosystem functionality. In Wyoming (USA), thousands of acres of land surface has been disturbed to extract natural resources. While traditional reclamation practices of these lands focused on site stabilization and weed control, more recent efforts have been made to restore ecosystem services. It has been suggested that a spatial and temporal mosaic of flowering species will benefit insect populations. In this study, we compared early seral reclamation sites (i.e., well pads undergoing interim reclamation) to reference areas at two points within a growing season. We found reference ecosystems were devoid of forb species, while one year old reclaimed sites contained late-season blooming Rocky Mountain beeplant (Cleome serrulata) and three-four year old well pads contained early-season blooming perennial forb species, mainly western yarrow (Achillea millefolium). We compared insect abundance and family richness on 6 well pads with early season perennial forbs and 6 well pads with the late season annual forb, Rocky Mountain beeplant to insect communities on adjacent reference areas. A total of 237 insects were found on early season reclaimed sites compared to 84 on reference sites, while 858 insects were found on late season reclaimed sites compared to 40 on reference sites. Insect abundance and family richness was significantly higher on reclaimed well pads compared to reference areas at both points in the growing season. We also found interesting differences in abundance at family levels.
Article
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Restoration of agricultural drylands globally, here farmlands and grazing lands, is a priority for ecosystem function and biodiversity preservation. Natural areas in drylands are recognized as biodiversity hotspots and face continued human impacts. Global water shortages are driving increased agricultural land retirement providing the opportunity to reclaim some of these lands for natural habitat. We used meta-analysis to contrast different classes of dryland restoration practices. All interventions were categorized as active and passive for the analyses of efficacy in dryland agricultural ecosystems. We evaluated the impact of 19 specific restoration practices from 42 studies on soil, plant, animal, and general habitat targets across 16 countries, for a total of 1,427 independent observations. Passive vegetation restoration and grazing exclusion led to net positive restoration outcomes. Passive restoration practices were more variable and less effective than active restoration practices. Furthermore, passive soil restoration led to net negative restoration outcomes. Active restoration practices consistently led to positive outcomes for soil, plant, and habitat targets. Water supplementation was the most effective restoration practice. These findings suggest that active interventions are necessary and critical in most instances for dryland agricultural ecosystems likely because of severe anthropogenic pressures and concurrent environmental stressors-both past and present.
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Drylands cover 41% of the Earth's terrestrial surface, play a critical role in global ecosystem function, and are home to over two billion people. Like other biomes, drylands face increasing pressure from global change, but many of these ecosystems are close to tipping points, which, if crossed, can lead to abrupt transitions and persistent degraded states. Their limited but variable precipitation, low soil fertility, and low productivity have given rise to a perception that drylands are wastelands, needing societal intervention to bring value to them. Negative perceptions of drylands synergistically combine with conflicting sociocultural values regarding what constitutes a threat to these ecosystems. In the present article, we propose a framework for assessing threats to dryland ecosystems and suggest we must also combat the negative perceptions of drylands in order to preserve the ecosystem services that they offer.
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Restoration efforts will be taking place over the next decade(s) in the largest scope and capacity ever seen. Immense commitments, goals, and budgets are set, with impactful wide‐reaching potential benefits for people and the environment. These are ambitious aims for a relatively new branch of science and practice. It is time for restoration action to scale up, the legacy of which could impact over 350 million hectares targeted for the U.N. Decade on Restoration. However, restoration still proceeds on a case‐by‐case, trial by error basis and restoration outcomes can be variable even under similar conditions. The ability to put each case into context‐ what about it worked, what didn't, and why, is something that the synthesis of data across studies can facilitate. The link between data synthesis and predictive capacity is strong. There are examples of extremely ambitious and successful efforts to compile data in structured, standardized databases which have led to valuable insights across regional and global scales in other branches of science. There is opportunity and challenge in compiling, standardizing, and synthesizing restoration monitoring data to inform the future of restoration practice and science. Through global collation of restoration data, knowledge gaps can be addressed and data synthesized to advance toward a more predictive science to inform more consistent success. The interdisciplinary potential of restoration ecology sits just over the horizon of this decade. Through truly collaborative synthesis across foci within the restoration community, we have the opportunity to rapidly reach that potential and achieve extraordinary outcomes together. This article is protected by copyright. All rights reserved.
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Drylands cover 41% of Earth’s surface and are the largest source of interannual variability in the global carbon sink. Drylands are projected to experience accelerated expansion over the next century, but the implications of this expansion on variability in gross primary production (GPP) remain elusive. Here we show that by 2100 total dryland GPP will increase by 12 ± 3% relative to the 2000–2014 baseline. Because drylands will largely expand into formerly productive ecosystems, this increase in dryland GPP may not increase global GPP. Further, GPP per unit dryland area will decrease as degradation of historical drylands outpaces the higher GPP of expanded drylands. Dryland expansion and climate-induced conversions among sub-humid, semi-arid, arid, and hyper-arid subtypes will lead to substantial changes in regional and subtype contributions to global dryland GPP variability. Our results highlight the vulnerability of dryland subtypes to more frequent and severe climate extremes and suggest that regional variations will require different mitigation strategies.
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Ecological restoration is practiced worldwide as a direct response to the degradation and destruction of ecosystems. In addition to its ecological impact it has enormous potential to improve population health, socio‐economic wellbeing, and the integrity of diverse national and ethnic cultures. In recognition of the critical role of restoration in ecosystem health, the United Nations declared 2021–2030 as the Decade on Ecosystem Restoration. We propose six practical strategies to strengthen the effectiveness and amplify the work of ecological restoration to meet the aspirations of the Decade: (1) incorporate holistic actions, including working at effective scale; (2) include Traditional Ecological Knowledge (TEK); (3) collaborate with allied movements and organizations; (4) advance and apply soil microbiome science and technology; (5) study and show the relationships between ecosystem health and human health; and (6) provide training and capacity‐building opportunities for communities and practitioners. We offer these in the hope of identifying possible leverage points and pathways for collaborative action among interdisciplinary groups already committed to act and support the UN Decade on Ecosystem Restoration. Collectively, these six strategies work synergistically to improve human health and also the health of the ecosystems on which we all depend, and can be the basis for a global restorative culture. This article is protected by copyright. All rights reserved.
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The challenges of restoration in dryland ecosystems are growing due to a rise in anthropogenic disturbance and increasing aridity. Plant functional traits are often used to predict plant performance and can offer a window into potential outcomes of restoration efforts across environmental gradients. We analyzed a database including 15 years of seeding outcomes across 150 sites on the Colorado Plateau, a cold desert ecoregion in the western United States, and analyzed the independent and interactive effects of functional traits (seed mass, height, and specific leaf area) and local biologically‐relevant climate variables on seeding success. We predicted that the best models would include an interaction between plant traits and climate, indicating a need to match the right trait value to the right climate conditions to maximize seeding success. Indeed, we found that both plant height and seed size significantly interacted with temperature seasonality, with larger seeds and taller plants performing better in more seasonal environments. We also determined that these trait‐environment patterns are not influenced by whether a species is native or non‐native. Our results inform the selection of seed mixes for restoring areas with specific climatic conditions, while also demonstrating the strong influence of temperature seasonality on seeding success in the Colorado Plateau region.
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Plant traits—the morphological, anatomical, physiological, biochemical and phenological characteristics of plants—determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits—almost complete coverage for ‘plant growth form’. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait– nvironmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
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In large areas of the world that are deeply scarred by desertification and hampered by low capacity for natural regeneration, the scaling‐up of ecological restoration and rehabilitation can be achieved only if it is low in cost with high return on investment, and shows promise of providing long‐lasting social‐economic as well as ecological benefits. In the Monte Austral region of Patagonia Argentina, concerted efforts are underway to facilitate scaling up of ecological restoration and rehabilitation practices. Here we evaluate financial costs and preliminary results of direct seeding as compared to outplanting of nursery‐grown seedlings of three native species (Atriplex lampa, Senecio subulatus var. subulatus, and Hyalis argentea var. latisquama) considered to be high priority dryland framework species. Comparative success is expressed in terms of plant survival and in monetary terms. The three candidate species showed low survival rates, ranging from 4.3% to 22.3%, after the first summer following direct seeding. In contrast, survival rates for planted seedlings of the same three taxa varied between 84 and 91%, after the first summer following reintroduction. However, cost of direct seeding varied between 1,693 and 1,772 US$ less per hectare, that is 64 % less than the cost of outplanting nursery seedlings. Therefore, in the search for ways to scale‐up ecological restoration and rehabilitation in drylands, direct seeding should receive more attention. We discuss the social and ecological perspectives and the way forward for direct seeding techniques in Patagonia. We also consider how costs could be reduced and effectiveness improved in large‐scale efforts. This article is protected by copyright. All rights reserved.