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Conservation and restoration of riparian vegetation in agricultural landscapes has had mixed success at protecting in‐stream habitat, potentially due to the mismatch between watershed‐scale impacts and reach‐scale restoration. Prioritizing contiguous placement of small‐scale restoration interventions may effectively create larger‐scale restoration projects and improve ecological outcomes. We performed a multi‐site field study to evaluate whether greater linear length of narrow riparian tree corridors resulted in measurable benefits to in‐stream condition. We collected data at 41 sites with varying upstream tree cover nested within 13 groups in rangeland streams in coastal northern California, United States. We evaluated the effect of riparian tree corridor length on benthic macroinvertebrate communities, as well as food resources, water temperature, and substrate size. Sites with longer riparian corridors had higher percentages of invertebrates sensitive to disturbance (including clingers and EPT taxa) as well as lower water temperatures and less fine sediment, two of the most important aquatic stressors. Despite marked improvement, we found no evidence that macroinvertebrate communities fully recovered, suggesting that land use continued to constrain conditions. The restoration of long riparian corridors may be an economically viable and rapidly implementable technique to improve habitat, control sediment, and counter increasing water temperatures expected with climate change within the context of ongoing land use.

Restoration frequently aims to improve native species biodiversity at a site, but practitioners have limited resources. In diverse ecosystems, the selective use of certain guilds or species can come at the cost of species that are more challenging to incorporate, resulting in the overall homogenization of the ecosystem and a relative loss of biodiversity. We surveyed practitioners who restore California prairies to understand their use of native annual forbs, an important component of the biodiversity in this ecosystem. We found that practitioners preferentially planted native perennial species, mainly grasses. Despite practitioners' recognition of the high conservation value of native annual forbs, they were hesitant to include this guild in their planting palettes because of high costs, low and unpredictable establishment, and lack of seed. We recommend that California annual prairie forbs be seeded in multiple years to enhance establishment, and that monitoring targets be designed to better reflect the high variability in interannual abundance of native annual forbs. These issues are not unique to California prairie, and more broadly, restoration objectives and research across a range of ecosystems should prioritize guilds that are more challenging to establish but are of high conservation concern.

Neotropical fruit bats (family Phyllostomidae) facilitate forest regeneration on degraded lands by dispersing shrub and tree seeds. Accordingly, if fruit bats can be attracted to restoration sites, seed dispersal could be enhanced. We surveyed bat communities at 10 sites in southern Costa Rica to evaluate whether restoration treatments attracted more fruit bats if trees were planted on degraded farmlands in plantations or island configurations versus natural regeneration. We also compared the relative influence of tree cover at local and landscape spatial scales on bat abundances. We captured 68% more fruit bat individuals in tree plantations as in controls, whereas tree island plots were intermediate. Bat activity also responded to landscape tree cover within a 200-m radius of restoration plots, with greater abundance but lower species richness in deforested landscapes. Fruit bat captures in controls and tree island plots declined with increasing landscape tree cover, but captures in plantations were relatively constant. Individual species responded differentially to tree cover measured at different spatial scales. We attribute restoration effects primarily to habitat structure rather than food resources because no planted trees produced fruits regularly eaten by bats. The magnitude of tree planting effects on fruit bats was less than previous studies have found for frugivorous birds, suggesting that bats may play a particularly important role in dispersing seeds in heavily deforested and naturally regenerating areas. Nonetheless, our results show that larger tree plantations in more intact landscapes are more likely to attract diverse fruit bats, potentially enhancing seed dispersal.

The first few years of tropical forest restoration can be expensive, especially when applied to expansive areas. In light of this, passive restoration has been recommended as a considerably cheaper or even free alternative. There are, however, both direct and indirect costs associated with passive restoration. First, the longer recovery time that is typically required in passive restoration can be perceived as project failure, especially when compared with nearby active restoration efforts. In the worst-case scenario, this can lead to the premature termination of a project by a landowner who would like to see more rapid or visible results. Second, passive restoration may be viewed as land abandonment, and in developing nations where land tenure is not always strictly enforced this may invite unanticipated uses, such as ranchers who may unintentionally or intentionally allow livestock to take advantage of the “unused” forage grass, thus setting back recovery efforts. Lastly, passive restoration does have direct financial costs, including material costs for establishing fences and repairing them, and labor costs for site vigilance. These upfront investments may need to be made repeatedly in passive restoration efforts, and for a longer time period than for an active restoration project. Both the direct and indirect costs should be considered prior to choosing passive restoration as a strategy in a particular restoration project.

The selection of ecological indicators is an important step toward more effective restoration monitoring. The debate between Reid (2015) and Durigan and Suganuma (2015) regarding the usefulness of species composition for monitoring restoration trajectory is timely and salient, but it lacks a middle way proposal to balance ecological relevance and practical viability. We propose a way forward to resolving this debate, namely using easily measurable functional traits, a type of compositional measure, as an indicator. Assessing functional composition trajectory may help overcome some limitations with taxonomic identification and provide more meaningful outcomes to evaluate restoration success.

+ . Moreover, there is a pressing need to restore forests to reduce erosion into nearby waterways and to conserve the high diversity of tropi-cal forest organisms. In certain areas of the tropics, agricultural land is being abandoned and undergoing secondary succession due to changes in commodity prices and urr al – urban migartion (Mar i n - Spiotta

We compare two successional models as guides for restoring native riparian understory species along a 160-km stretch of the Sacramento River in California. In 2001 and 2007, we surveyed cover, frequency, and richness of native and exotic understory species in 15 sites planted (1989–1996) with overstory species to determine whether native understory species colonized naturally (passive relay floristics model). In 2007, we surveyed 20 additional sites (planted 1997–2003) in 14 of which understory species were planted (initial floristics model) to evaluate whether planting accelerated community recovery. We surveyed 10 remnant forests as references for successional trajectories. Mean cover and frequency of natives changed little over time in sites where they were not planted initially; increases in native cover in a few sites were primarily due to a single common species (Galium aparine). Species composition shifted from light-demanding to shade-adapted species, both exotic and native, in response to a doubling of overstory cover. Sites with high intensity understory plantings had greater cover and frequency of native understory species than unplanted sites, but were still low relative to reference forests. Light-demanding natives (e.g., Artemisia douglasiana, Rubus ursinus, and grasses) established in sites where they were planted; however, a shade-adapted species (Carex barbarae) did not survive well. Our research indicates that the passive relay floristics and the initial floristic composition approaches serve to restore a few common native understory species, but that planting species as site conditions become appropriate (active relay floristics model) will be needed to restore entire native understory communities.

Planting tree seedlings in small patches (islands) has been proposed as a method to facilitate forest recovery that is less expensive than planting large areas and better simulates the nucleation process of recovery. We planted seedlings of four tree species at 12 formerly agricultural sites in southern Costa Rica in two designs: plantation (entire 50 × 50 m area planted) and island (six patches of three sizes). We monitored seedling survival, height, and canopy area over 3 years. To elucidate mechanisms influencing survival and growth, we measured soil and foliar nutrients, soil compaction, and photosynthesis. Survival of all species was similar in the two planting designs. Seedling height and canopy area were greater in plantations than islands at most sites, and more seedlings in islands decreased in height due to damage incurred during plot maintenance. Survival, height, and canopy area were both site- and species-specific with the two N-fixing species (Inga edulis and Erythrina poeppigiana) greater than the other species (Terminalia amazonia and Vochysia guatemalensis). Foliar N was higher in Terminalia and Vochysia in sites where Inga growth was greater. Soil nutrients, however, explained a small amount of the large differences in growth across sites. Leaf mass per area was higher in islands, and P use efficiency was higher in plantations. Our results show advantages (good seedling survival, cheaper) and disadvantages (more seedling damage, slightly lower growth) to the island planting design. Our study highlights the importance of replicating restoration strategies at several sites to make widespread management recommendations.

After tropical lands have been abandoned from anthropogenic pressures, often forest structure and some species recover naturally. Studies suggest, however, that matureforest species are frequently slow to establish and an active management strategy may be necessary. We tested direct seeding of mature-forest species as a restoration strategy in sites previously used for slash-and-burn agriculture in semi-evergreen, seasonal forest in the Yucatan peninsula, Mexico, and evaluated when in the successional process this strategy had the highest success rate. We planted three mature-forest species (Brosimum alicastrum, Enterolobium cyclocarpum ,a ndManilkara zapota) in three forest ages: recently abandoned ( 50 years). Overall, an average of 5–41% of planted seeds germinated, and 3–35% were present through the seedling stage. Only M. zapota had higher germination in the reference forest than in the other forest ages, whereas the other two species had similar percentage germination in all successional stages. Of the seeds that germinated in the 8–15 years sites and the reference forest, 58–95% of the seedlings survived through the end of the study, whereas survival in recently abandoned sites was less than 50% in most cases. Seedling height was generally similar across forest age categories. Our results suggest that direct seeding these mature-forest species after the first few years of natural succession could be a successful strategy to accelerate and guarantee their establishment.

Efforts to restore tropical forest in abandoned pasture are likely to be more successful when bird visitation is promoted because birds disperse seeds and eat herbivorous arthropods that damage leaves. Thus, it is critical to understand bird behavior in relation to different restoration strategies. We measured the likelihood of visitation, number of visits, and duration of visits for all birds and for Cherrie’s Tanager (Ramphocelus costaricensis), a common seed disperser, in five sizes of forest restoration patches planted with four tree species in southern Costa Rica. We predicted that the largest patches, and the tree species with the greatest canopy cover, would be visited most frequently and have the longest visits because we assumed that these patch types had the greatest food resources and the lowest predation risk. We found that birds were more likely to visit large patches and the tree species with the highest canopy cover (Inga edulis). Birds visited Inga trees more often and stayed in Inga and Erythrina poeppigiana trees for longer periods of time than in other tree species. We found similar results for Cherrie’s Tanagers. Thus, we identified two factors, tree species and patch size, which may be manipulated in restoration projects to increase bird visitation.

With the increasing need to restore former agricultural lands worldwide and in the tropics, in particular, it is critical to explore different models for how to restore these lands in a cost-effective manner which best simulates natural forest recovery and provides for human livelihoods. We propose that agro-successional restoration, which we define as incorporating a range of agroecology and agroforestry techniques as a transition phase early in forest restoration, could be used more widely to overcome socioeconomic and ecological obstacles to restoring these lands. Over centuries, farmers and scientists have developed various agroforestry techniques that aim to cultivate crops and trees, in a range of crop types, time periods of cultivation (a few years to several decades), and complexity of species planted. The management practices used in these systems, such as weeding and increasing soil fertility, parallel those used in many forest restoration efforts. The synergism between these approaches is evidenced by many existing agro-successional examples currently used by smallholders in the tropics. Benefits of the agro-successional model include extending the management period of restoration, offsetting some management costs, providing food security for small landholders, and involving small landholders in the restoration process.

The goal of restoration is to accelerate ecosystem recovery, but in ecosystems that naturally regenerate rapidly restoration techniques need to be selected carefully to facilitate rather than impede natural recovery. We compared the effects of five restoration techniques, such as plowing the soil, removing grasses, adding forest litter, seeding, and planting nursery-growing seedlings, on the regeneration of seasonal deciduous forest trees in four abandoned pastures in central Brazil. We monitored all woody stems immediately prior to treatments and again 14 months after the treatments. We recorded an average of 16,663 tree stems per hectare and a total of 83 species before implementing treatments. Planting strongly increased species richness; adding litter and seeding had weaker positive effects on richness; and plowing and grass removal had no effect. Plowing substantially reduced the density of naturally established stems. Despite the high survival of planted seedlings, stem density in planting treatments did not change because the tractor and digging holes to plant seedlings caused mortality of naturally regenerating seedlings. Tree stems grew more in the grass release plots than in the control plots. Our results suggest that early succession of seasonal deciduous forest in pastures in the region studied does not need to be stimulated once the perturbation is stopped and that intensive restoration efforts may actually slow recovery. We recommend only enrichment planting of seedlings that are not able to resprout.

Human activities have degraded riparian systems in numerous ways, including homogenization of the floodplain landscape and minimization of extreme flows. We analyzed the effects of changes in these and other factors for extinction‐colonization dynamics of a threatened Bank Swallow population along the upper Sacramento River, California, U.S.A. We monitored Bank Swallow distributions along a 160-km stretch of the river from 1986‐1992 and 1996‐2003 and tested whether site extinctions and colonizations corresponded with changes in maximum river discharge, surrounding land cover, estimated colony size, temperature, and precipitation. Colonization probabilities increased with maximum discharge. Extinction probabilities decreased with proximity to the nearest grassland, decreased with colony size, and increased with maximum discharge. To explore the implications for restoration, we incorporated the statistically estimated effects of distance to grassland and maximum discharge into simple metapopulation models. Under current conditions, the Bank Swallow metapopulation appears to be in continued decline, although stable or increasing numbers cannot be ruled out with the existing data. Maximum likelihood parameters from these regression models suggest that the Sacramento River metapopulation could be restored to 45 colonies through moderate amounts of grassland restoration, large increases in discharge, or direct restoration of nesting habitat by removing approximately 10% of existing bank protection (riprap) from suitable areas. Our results highlight the importance of grassland restoration, mixed benefits of restoring high spring discharge, and the importance of within-colony dynamics as areas for future research.

Authors submitting to Restoration Ecology and other international publishing venues need to give careful thought to framing their manuscripts to maximize the relevance of their message to an international audience. I discuss five questions that all authors should reflect upon in framing their papers. Namely, authors should consider which conclusions will be most relevant to an international audience, the scope of systems to which these conclusions apply, and the amount of data supporting these conclusions. Authors should also think about the breadth of the literature cited and the degree of replication of the study. Localized studies are critical to implementing ecological restoration, but all authors, regardless of their intended outlet, need to carefully consider their audience. To publish successfully in an international journal, such as Restoration Ecology, authors need to frame their results within a broad context.

Tropical forests are being cleared at an alarming rate although our understanding of their ecology is limited. It is therefore essential to design restoration experiments that both further our basic knowledge of tropical ecology and inform management strategies to facilitate recovery of these ecosystems. Here we synthesize the results of research on tropical montane forest recovery in abandoned pasture in Costa Rica to address the following questions: (1) What factors limit tropical forest recovery in abandoned pasture? and (2) How can we use this information to design strategies to facilitate ecosystem recovery? Our results indicate that a number of factors impede tropical forest recovery in abandoned pasture land. The most important barriers are lack of dispersal of forest seeds and seedling competition with pasture grasses. High seed predation, low seed germination, lack of nutrients, high light intensity, and rabbit herbivory also affect recovery. Successful strategies to facilitate recovery in abandoned pastures must simultaneously overcome numerous obstacles. Our research shows that establishment of woody species, either native tree seedlings or early-successional shrubs, can be successful in facilitating recovery, by enhancing seed dispersal and shading out pasture grasses. On the contrary, bird perching structures alone are not an effective strategy, because they only serve to enhance seed dispersal but do not reduce grass cover. Remnant pasture trees can serve as foci of natural recovery and may enhance growth of planted seedlings. Our results highlight the importance of: (1) understanding the basic biology of an ecosystem to design effective restoration strategies; (2) comparing results across a range of sites to determine which restoration strategies are most generally useful; and (3) considering where best to allocate efforts in large-scale restoration projects.

The question of how society is going to pay for restoration has received little open discussion. We review existing literature and examples to explore two questions: How should ecological and economic considerations be balanced in determining expenditures on restoration projects? and How is society going to pay for the substantial costs involved? We discuss a number of different techniques for determining the amount of money to allocate to restoration efforts, including ecosystem replacement costs, quantifying ecosystem services, contingent valuation, and surrogate market price techniques. We then review different strategies for paying for restoration including private funding by the party responsible for the damage, public funding through taxes, voluntary contributions, and various public/private partnerships. We conclude by discussing other considerations in developing strategies to pay for restoration, including uncertainty, time-scale, evaluating success, and regional planning.

Efforts to reforest tropical pasture with native tree species have increased in recent years, yet little is known about the physiology of most tropical trees. The goal of this study was to assess the effect of habitat on photosynthetic responses to light for seedlings of four native rainforest species (Calophyllum brasiliense, Ocotea glaucosericea, Ocotea whitei, and Sideroxylon portoricense) planted to facilitate tropical rainforest recovery in southern Costa Rica. Seedlings were planted in primary forest, in open abandoned pasture, and in the shade of remnant trees within the pasture. Growth, morphology, photosynthetic gas exchange responses to light, and chlorophyll fluorescence (an indication of the integrity of photosynthetic processes) were measured in the three habitats. Height and leaf area were generally greater for seedlings in tree shade compared to those in the forest and open pasture. Photosynthetic rates were higher for plants in open pasture and tree shade compared to those in the forest for two of the four species. Chlorophyll fluorescence results indicated flexibility in the photosynthetic processing of light energy that may help plants tolerate the bright light of the pasture. This study demonstrates that, for certain species, seedlings under remnant pasture trees do not exhibit the level of photosynthetic stress experienced in open abandoned pasture. Seedling responses to light, in combination with other factors such as increased nutrient input through litterfall, help explain the enhanced growth of seedlings under remnant pasture trees. Planting seedlings under remnant trees may increase the success of future efforts to restore tropical forest in abandoned agricultural land.

We agree with Prach and del Moral that passive recovery is often a desirable and effective restoration strategy. Passive and various active restoration approaches need to be weighed on a case-by-case basis and depend on the goals, relative rates of recovery desired, and various social and financial costs implicit in each option. That said, we stress that passive restoration has a unique set of challenges and costs, which we highlighted in our original article and briefly reiterate here.

Book Review BOOK REVIEW Large-Scale Forest Restoration David Lamb (2015) Routledge, London, 302 pages, $145.00 (hardback), ISBN ver the past few years, there O have been numerous global, regional, and national targets set for large-scale forest restoration to con- serve biodiversity, provide a range of ecosystem services, and ensure the well-being of human communities. Most notable of these are the Bonn Challenge and the more recent New York Declaration on Forests, which aim to restore 150 million hectares of forest worldwide by 2020 and 350 million hectares by 2030. David Lamb’s recent book Large-Scale For- est Restoration provides a timely overview of the complex issues that must be addressed to achieve these ambitious goals. Lamb draws on a range of examples from his three decades of experience teaching forest ecology and advising on numerous forest restoration projects worldwide for international organizations, includ- ing the World Bank, the Food and Agriculture Organization, and the International Union for the Con- servation of Nature. He recognizes the complexity of the topic and its many interwoven strands, offering glimpses into an array of contentious debates without taking a strong stance, thus inviting readers to draw their own conclusions. This book fills a niche as the first to synthesize the vast arena of work on large-scale forest restoration, and most impor- tantly, to integrate the ecological, social, and economic factors. Unlike Lamb’s prior book, Regreening the Bare Hills (2011), which focuses on restoration in the Asia-Pacific region, Large-Scale Forest Restoration spans a Restoration Ecology range of countries, forest types, and sociopolitical systems. The beginning of the book pro- vides a context for large-scale forest restoration by discussing factors leading to degradation, and the extent to which reforestation can serve both human and ecological goals. The second chapter provides a succinct historical perspective on the evolution of the timber industry over the past century. The next two chapters describe landscape-level ecological constraints and silvi- cultural management practices associated with natural and planted forest regrowth. The subsequent chapters address questions of where and how much restoration is needed as a function of different land uses and ecosystem services (e.g. hydro- logic processes, carbon sequestration, and biodiversity conservation). Chapter 7 discusses the choices and trade-offs facing landholders as they attempt to reconcile production and conservation objectives to achieve multifunctionality. The penultimate chapter investigates market-based, regulatory, and institutional policies needed to carry out and sustain future large-scale restoration efforts. The book closes by putting forth questions on governance, scale, and climate change certain to elicit fur- ther consideration by the reader. Lamb uses a combination of pho- tographs, tables, and diverse case studies in each chapter to high- light main points, and includes an extensive bibliography. Although the intended audi- ence for the book is not explicitly stated, this book is a broad entree to the extensive literature on the many facets of forest restoration and will be useful to forestry stu- dents and others in related fields. Moreover, we think that the book could be particularly relevant to restoration practitioners who imple- ment projects on the ground and are seeking to integrate their work into a larger global restoration con- text. Unfortunately, the price of the book may make it prohibitive for those who could most benefit. A paperback version and transla- tion into other languages would make it more accessible to a broader audience. As an interdisciplinary team of primarily graduate students with expertise in both natural and social sciences, and experience in tropical and temperate forest restoration, we brought diverse perspectives to this review. We found the treat- ment of certain topics to be uneven, which is not surprising for a single author writing on such a complex subject. The book emphasizes plan- tation silviculture, while overlooking agroforestry and underemphasiz- ing technical assistance and rural extension as public policy options. Discussion of international forest policies and regulations, institutional arrangements, and livelihood issues was patchy. Despite the focus on large-scale reforestation (>10,000 ha) and on the challenge of “scaling-up,” the book lacked an analytical frame- work for integrating diverse types of land managers—both small and large—in reforestation projects. More sustained attention to the challenge of how to coordinate dif- ferent actors, including cooperative or community-based approaches, would have been welcome. Although the book offers valuable case studies and models regarding various silvi- cultural techniques and ecological approaches, it falls short of repre- senting the variety of constraints within which land managers make decisions on the ground. Perhaps due to the large breadth of topics, the book’s organization often felt erratic and transitions were not always intuitive. Chapter titles and section headings were sometimes misleading relative to the content. For example, Chapter 6 (“How much forest restoration is

Lack of seed dispersal has been shown to be a major factor limiting tropical forest recovery in abandoned pasture land. The goal of this work was to determine whether bird perching structures serve to enhance seed dispersal and seedling establishment in an abandoned pasture in Costa Rica. Two types of perching structures (crossbar and branch) were tested. Bird visitation rates were significantly higher on branch than on crossbar perches. The number of animal-dispersed seeds was significantly higher below branch perches than below crossbar perches or in open pasture. Despite differences in seed rain, percent cover of animal-dispersed plants and the number of seedlings of animal-dispersed plant species were similar below both perch types and in open pasture. Baiting perches with bananas did not increase either bird visitation rates or seed rain. These results suggest that, although bird perching structures increase seed dispersal, they do not overcome other barriers to tropical forest recovery such as seed predation and low seed germination.

Despite the critical role insects play in ecosystem functioning, there has been little study of factors affecting their reestablishment in restored ecosystems. The goals of this research were to quantify the nectar resources provided by reclaimed coal surface mines and to examine the role nectar resources play in determining butterfly community composition on these sites. Adult butterfly communities and nectar resources were sampled on 18 reclaimed coal surface-mined sites and five unmined hardwood sites in southwestern Virginia. Recently, reclaimed sites provided an average of 300 times the nectar abundance of the surrounding hardwoods, and nectar abundance and species richness decreased with time since reclamation. Total nectar abundance was highly correlated with total butterfly abundance and species richness for the entire flight season; these variables were also significantly correlated among sites during most of the 12 sampling periods during the flight season. In only a few cases, however, were butterfly and nectar abundance and species richness significantly correlated within individual sites during the flight season. These results suggest that, although adults of many butterfly species move in response to nectar availability, nectar resources are not sufficiently limiting that their life histories have evolved to maximize nectar resources temporally. While planting species in restored areas that provide abundant nectar will likely attract adult butterflies, this is only one of a number of habitat variables that must be considered in efforts to restore butterfly populations. Finally, adult butterflies appear to have limited utility as indicators of revegetation success.