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20 Pág. Departamento de Medio Ambiente y Agronomía​, 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., We would like to thank the supporters of the Global Arid Zone Project. The intellectual and energetic input of the network participants made this work possible. We also acknowledge the many employers and funding agencies that supported projects and the authors’ time in preparing this work and contributing data to the GAZP database. Please note that any use of trade, firm or product names is for descriptive purposes only and does not imply endorsement by the US Government

1 Pág. Correción errata., In the version of this Article originally published, the surname of author Tina Parkhurst was incorrectly written as Schroeder. This has now been corrected.

No standardized, objective methodology exists for optimizing seeding rates when establishing herbaceous plant cover for pastures, hay fields, ecological restoration, or other revegetation activities. Seeding densities, fertilizer use, season of seeding, and the interaction of these treatments were tested using native plants on degraded sites in northern British Columbia, Canada. A mixture of 20% Achillea millefolium, 20% Carex aenea, 20% Elymus glaucus, 20% Festuca occidentalis, 16% Geum macrophyllum, and 4% Lupinus polyphyllus seed was applied at 0, 375, 750, 1,500, 3,000, and 6,000 pure live seed (PLS) per m 2 in 2.5 3 2.5‐m rototilled test plots, established in the fall and spring, with and without fertilizer. There was no significant difference in plant cover of sown species between fall seeding and spring seeding, and few treatment interactions were identified in the first 2 years after sowing. There was no significant difference in cover between seed densities of 3,000 and 6,000 PLS/m 2 in the first year, nor among 1,500, 3,000, and 6,000 PLS/m 2 treatments in the second year. Seed densities as low as 375 PLS/m 2 produced year 2 plant cover equivalent to that observed at 3,000 PLS/m 2 in year 1. Plots sown to seed densities less than or equal to 750 PLS/m 2 generally exhibited an increase (infilling) in plant density from year 1 to year 2, whereas plots sown to seed densities greater than or equal to 1,500 PLS/m 2 generally exhibited a decrease (density-dependent mortality) in plant density. These results imply a most efficient sowing density between 750 and 1,500 PLS/m 2 (corresponding to 190‐301 established plants . m 22 after two growing seasons). It is suggested that net changes in plant populations observed over a range of sowing densities are a robust and objective means of determining optimal sowing densities for the establishment of herbaceous perennials.

Normal 0 false false false MicrosoftInternetExplorer4 The persistence and recovery of devil’s club ( Oplopanax horridus (Sm.) Miq., Araliaceae) after clearcut logging in northwestern British Columbia, Canada, is investigated through a series of retrospective surveys. This species remains important to the traditional culture of many First Peoples of western North America and is being studied for its biological abilities by medical researchers. Based on observations in 16 clearcuts that had been logged 3 to 37 years earlier, it is clear that devil’s club can survive and grow in these disturbed habitats and appears to take at least 10 years for sizes to recover to those found in old-growth forests. The most successful populations of post-logging devil’s club probably escaped damage during logging operations, showed no recent signs of fire, and were associated with loose piles of dead branches, tree tops, and rotten logs. Consideration of these factors in forest management, in combination with the time since logging, should facilitate the resilience and sustainability of this species. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;}