Improving Planting Stocks for the Brazilian Atlantic Forest Restoration through Community‐Based Seed Harvesting Strategies

High‐diversity reforestation can help jumpstart tropical forest restoration, but obtaining viable seedlings is a major constraint: if nurseries do not offer them, it is hard to plant all the species one would like. From 2007 to 2009, we investigated five different seed acquisition strategies employed by a well‐established tree nursery in southeastern Brazil, namely (1) in‐house seed harvesters; (2) hiring a professional harvester; (3) amateur seed harvesters; or (4) a seed production cooperative, as well as (5) participating in a seed exchange program. In addition, we evaluated two strategies not dependent on seeds: harvesting seedlings from native tree species found regenerating under Eucalyptus plantations, and in a native forest remnant. A total of 344 native tree and shrub species were collected as seeds or seedlings, including 2,465 seed lots. Among these, a subset of 120 species was obtained through seed harvesting in each year. Overall, combining several strategies for obtaining planting stocks was an effective way to increase species richness, representation of some functional groups (dispersal syndromes, planting group, and shade tolerance), and genetic diversity of seedlings produced in forest tree nurseries. Such outcomes are greatly desirable to support high‐diversity reforestation as part of tropical forest restoration. In addition, community‐based seed harvesting strategies fostered greater socioeconomic integration of traditional communities in restoration projects and programs, which is an important bottleneck for the advance of ecological restoration, especially in developing countries. Finally, we discuss some of the limitations of the various strategies for obtaining planting stocks and the way forward for their improvement.     

Genetic diversity of reintroduced tree populations in restoration plantations of the Brazilian Atlantic Forest

Long‐term ecological success of large‐scale restoration programs planned for the next decades will rely on genetic diversity (GD) of reintroduced or colonizing species, a limiting factor in highly fragmented landscapes. In small and isolated natural remnants or restoration areas, substantial reduction in population's size or connectivity may lead to local extinctions due to the accumulation of deleterious recessive alleles and ongoing reduction of fecundity, plant vigor, recruitment success, and adaptive potential. Despite the paramount role of GD for species persistence, its levels in restoration programs are poorly known. We assessed the GD of four model tree species (different succession stages, dispersal, and pollination syndromes) from the Brazilian Atlantic Forest, comparing two high‐diversity restoration plantations, one forest fragment and one conserved remnant. Contrary to the expectation that the plantation strategies adopted in the restoration programs could result in genetic composition homogenization, we found that restoration areas established heterogeneous genetic groups with similar levels of neutral GD and inbreeding to those observed in natural forest remnants. This pattern was consistent across the four functionally different tree species, despite some species idiosyncrasies. For instance, we observed lower allelic richness in early successional species in restoration sites, suggesting that some species may be more prone to reintroduction with lower GD. Thus, we advocate the use of high GD levels in restoration to support biodiversity conservation in human‐modified landscapes, thus reinforcing the role of ecological restoration for recovering the diversity of genes—the basic constituent of biodiversity.     

Emerging Threats and Opportunities for Large‐Scale Ecological Restoration in the Atlantic Forest of Brazil

Over the past 150 years, Brazil has played a pioneering role in developing environmental policies and pursuing forest conservation and ecological restoration of degraded ecosystems. In particular, the Brazilian Forest Act, first drafted in 1934, has been fundamental in reducing deforestation and engaging private land owners in forest restoration initiatives. At the time of writing (December 2010), however, a proposal for major revision of the Brazilian Forest Act is under intense debate in the National Assembly, and we are deeply concerned about the outcome. On the basis of the analysis of detailed vegetation and hydrographic maps, we estimate that the proposed changes may reduce the total amount of potential areas for restoration in the Atlantic Forest by approximately 6 million hectares. As a radically different policy model, we present the Atlantic Forest Restoration Pact (AFRP), which is a group of more than 160 members that represents one of the most important and ambitious ecological restoration programs in the world. The AFRP aims to restore 15 million hectares of degraded lands in the Brazilian Atlantic Forest biome by 2050 and increase the current forest cover of the biome from 17% to at least 30%. We argue that not only should Brazilian lawmakers refrain from revising the existing Forest Law, but also greatly step up investments in the science, business, and practice of ecological restoration throughout the country, including the Atlantic Forest. The AFRP provides a template that could be adapted to other forest biomes in Brazil and to other megadiversity countries around the world.     

Cultural Ecosystem Services and Popular Perceptions of the Benefits of an Ecological Restoration Project in the Brazilian Atlantic Forest

It is essential to understand how ecological restoration (ER) improves human well‐being in order to justify more investments and upscaling in this emergent field of action. As part of a 22‐year‐old, 80 ha ER project being carried out around a water reservoir that supplies drinking water to the city of Iracemápolis (population 19,700), in the mega‐diversity Atlantic Forest biome of Brazil, we assessed local community perceptions of the tangible and intangible benefits expected to arise from this project. A detailed questionnaire was completed for 292 members of the local community to gauge perceptions of benefits arising from various cultural and provisioning ecosystem services (ESs; especially safe and clean drinking water) provided by the 80 ha forest restoration project. A striking 94% of those interviewed wanted more ER projects in their community. Participants reported an appreciation for cultural ESs such as esthetic landscape improvement, tourism, recreation, as well as various religious, spiritual, and educational services. In addition, 87% of interviewees believed that the restoration project improved the quality of their drinking water, and 63% said they would agree to an increase in water tariffs if the proceeds were to be invested in more forest restoration. Judging from this study, investigation and subsequent communication of popular perceptions of the various benefits of ER projects could promote consensus‐building and support for projects among stakeholders, and inform governmental and societal investments in restoration .     

Relations Between Regional–Local Habitat Loss and Metapopulation Properties of Epiphyllous Bryophytes in the Brazilian Atlantic Forest

Richness and occupancy patterns of epiphyll bryophytes in a fragmented landscape of tropical rain forests in northeastern Brazil (Murici Ecological Station) were investigated to assess the influence of regional and local disappearance of habitat on epiphyllous metapopulation indicators. Bryophytes were collected from ten forest fragments, from the fragment's border to 100 m inside the forest. The number of colonized phorophytes and the cover on leaves were scored. Decreasing trends in regional and local abundance linked to habitat loss were observed, which may be related to the sexual and asexual expression. Although fertility was not related to constancy in the fragments, frequently fertile species colonized more sites within fragments than infertile species. Landscape metrics and indicators of habitat quality explained better the variation in epiphyll richness and occupancy than distance from the forest's edge. This suggests that the abrupt habitat quality modification resulting from edge creation is secondary in the area studied, while irreversible landscape modifications still play an important role. The results add to empirical support that metapopulations are prone to negative and long-term effects in fragmented landscapes. Thus, the selection of priority areas for conservation must take into account the remaining amount of habitat as well as the connectivity between the landscape's patches.     

Long‐term Spatial Changes in the Distribution of the Brazilian Atlantic Forest

The aim of this study is to represent simultaneously changes in the spatial distribution of the Atlantic forest during the last 17,000 years. To characterize such changes, here we focused on three different forest physiognomies, evergreen, semi‐deciduous, and Araucaria, and we provide a list of indicator taxa for each class retrieved from the original published datasets. A review of the published fossil pollen records allowed us to classify regional behaviors in three main areas of distribution, north of 15°S, between 15° and 23°S and south of 23°S latitude that correspond to three climatic geographical barriers. Statistical probability density function method was used to illustrate changes in forest physiognomies throughout the three distribution areas. We show that the three modern barriers also functioned through the past. Asynchronous patterns of forest physiognomies are linked to an antiphasing pattern of monsoon precipitation between the northern and central area, whereas in the southern area, it is linked to the frequency and intensity of the polar advection in the subtropics. Our results attest to strong climate forcing on forest distribution between the late glacial and the interglacial period. They call into question the common reference to the last glacial maximum as a major (and sometimes as the only) driver of forest‐related vicariance and genetic diversity patterns, but suggest that instead, orbital cycles were the main drivers of the successive expansion/contraction of the Atlantic forest throughout the Quaternary.     

Experimental Native Tree Seedling Establishment for the Restoration of a Mexican Cloud Forest

The cloud forests of Mexico have been degraded and severely fragmented, and urgently require restoration. However, progress with restoration has been constrained by a lack of information concerning the seedling ecology of native tree species. An experiment was therefore conducted to assess the influence of different environmental factors on the seedling survival and growth of four native tree species (Fagus grandifolia var. mexicana, Carpinus caroliniana, Symplocos coccinea, and Quercus acutifolia). The seedlings were established on three sites, in two contrasting environments: inside forest fragments and on adjacent agricultural land. Highly significant differences were recorded in seedling survival and growth among sites, environments, species, and interactions between these factors. Highest survival was recorded for Quercus, which uniquely among the four species displayed the same survival percentage inside and outside the forest. Survival of the other species was higher inside the forest. In contrast, growth rates of all four species were higher outside the forest. The most important cause of mortality outside the forest was desiccation, although significant seedling predation was also observed on two sites. Results indicate that all four species can be established successfully both within forest fragments and in neighboring agricultural areas, emphasizing the scope for forest restoration. However, the interactions observed between species, sites, and environments highlight the importance of accurate species–site matching if optimum rates of growth and survival are to be obtained. Quercus spp. have great potential for establishment on agricultural sites.     

Landscape‐scale lidar analysis of aboveground biomass distribution in secondary Brazilian Atlantic Forest

Secondary forests account for more than half of tropical forests and represent a growing carbon sink, but rates of biomass accumulation vary by a factor of two or more even among plots in the same landscape. To better understand the drivers of this variability, we used airborne lidar to measure forest canopy height and estimate biomass over 4529 ha at Serra do Conduru Park in Southern Bahia, Brazil. We measured trees in 30 georeferenced field plots (0.25‐ha each) to estimate biomass using allometry. Then we estimated aboveground biomass density (ABD) across the lidar study area using a statistical model developed from our field plots. This model related the 95th percentile of the distribution of lidar return heights to ABD. We overlaid this map of ABD on a Landsat‐derived forest age map to determine rates of biomass accumulation. We found rapid initial biomass regeneration (~6 Mg/ha yr), which slowed as forests aged. We also observed high variability in both height and biomass across the landscape within forests of similar age. Nevertheless, a regression model that accounted for spatial autocorrelation and included forest age, slope, and distance to roads or open areas explained 62 and 77 percent of the landscape variation in ABD and canopy height, respectively. Thus, while there is high spatial heterogeneity in forest recovery, and the drivers of this heterogeneity warrant further investigation, we suggest that a relatively simple set of predictor variables is sufficient to explain the majority of variance in both height and ABD in this landscape.     

Effectiveness of seed sowing techniques for sloped restoration sites

Practitioners are challenged with choosing among many potentially effective methods for sowing seed in ecological restoration projects to achieve sufficient native plant establishment. We tested the effectiveness of seed sowing techniques on moderate and steep slopes in a Mediterranean climate by measuring native seedling density immediately following germination, as well as plant density, recruitment success, and soil movement through the second growing season. We calculated cost effectiveness of different methods as the native plant density per dollar spent sowing seed. While all sowing techniques resulted in significant native establishment compared with unseeded controls, hydro seeding on moderate slopes was the most cost effective (native seedlings established per dollar spent). Although all steep‐sloped seeding techniques resulted in high densities of native species, all methods also resulted in significant soil loss. Shrubs preferred hand seeding followed by jute netting on steep slopes, while forbs reached greatest densities with hydro seeding on moderate slopes. Seedlings of species with heavy seeds were present in greater densities than species with lighter seeds in imprint sowing treatments. The “best” seed sowing technique varied depending on slope and metric of success (native density, species richness, shrub density, or forb density). Different combinations of slope, technique, and success metric resulted in significantly different project costs, which implies opportunities for savings given careful decision‐making relative to mitigation needs on heterogeneous landscapes. Evaluations of techniques for restoring slopes are limited, yet critical for expanding the area capable of being restored and the application of limited conservation funding.     

Shrub influences on seedling performance when restoring the slow‐growing conifer Pilgerodendron uviferum in southern bog forests

Forest restoration is most efficient if it can take advantage of facilitative interactions between established vegetation and planted trees. However, positive and negative interactions have been identified in a number of plant communities. After centuries of anthropogenic fires, forest recovery has been extremely slow in southern bog forests previously dominated by the slow‐growing and vulnerable conifer Pilgerodendron uviferum on Chiloé Island, Chile. Today, the landscape is dominated by secondary shrublands with scattered patches of Sphagnum moss and limited natural tree regeneration. We hypothesized that the retention of secondary shrubs facilitates the early performance of P. uviferum restoration plantings by providing better microsite conditions. To test this hypothesis, we compared the response of seedlings planted on sites prepared at two levels of intervention: after shrubs had been removed or where shrubs were retained. Shrub retention showed a nurse‐plant effect on P. uviferum seedlings 4 years after planting, which resulted in reduced physiological stress (measured as Fv/Fm) for seedlings, as well as reduced browsing. Consequently, the seedlings growing in areas with shrub retention had larger height increment and higher vitality than those in areas where shrubs had been removed. Thus, the more open micro‐site conditions created by shrub removal resulted in generally poorer seedling performance, although seedling mortality—which was low overall (approximately 2–4%)—showed no significant difference between the two levels of intervention. These findings have direct implications for the restoration of slow‐growing conifers that can tolerate extreme wet conditions in highly degraded forests.     

The role of natural regeneration to ecosystem services provision and habitat availability: a case study in the Brazilian Atlantic Forest

Natural regeneration provides multiple benefits to nature and human societies, and can play a major role in global and national restoration targets. However, these benefits are context specific and impacted by both biophysical and socioeconomic heterogeneity across landscapes. Here, we investigate the benefits of natural regeneration for climate change mitigation, sediment retention and biodiversity conservation in a spatially explicit way at very high resolution for a region within the global biodiversity hotspot of the Atlantic Forest. We classified current land‐use cover in the region and simulated a natural regeneration scenario in abandoned pasturelands, areas where potential conflicts with agricultural production would be minimized and where some early stage regeneration is already occurring. We then modeled changes in biophysical functions for climate change mitigation and sediment retention, and performed an economic valuation of both ecosystem services. We also modeled how land‐use changes affect habitat availability for species. We found that natural regeneration can provide significant ecological and social benefits. Economic values of climate change mitigation and sediment retention alone could completely compensate for the opportunity costs of agricultural production over 20 yr. Habitat availability is improved for three species with different dispersal abilities, although by different magnitudes. Improving the understanding of how costs and benefits of natural regeneration are distributed can be useful to design incentive structures that bring farmers’ decision making more in line with societal benefits. This alignment is crucial for natural regeneration to fulfill its potential as a large‐scale solution for pressing local and global environmental challenges.     

Restoring the Victorian Western (Basalt) Plains grassland. 1. Laboratory trials of viability and germination, and the implications for direct seeding

Summary   The Victorian Western (Basalt) Plains grassland is one of Australia's most threatened plant communities. Practitioners using seed for its restoration need to know whether seed can be sown fresh or whether it requires an after-ripening period. This study assessed the viability and germination of freshly harvested wild seed from 64 grassland species indigenous to the Basalt Plains of western Victoria. The seed was collected as part of a broader experiment that examined the potential of direct-sown complex seed mixes for the restoration of grassland communities. The germination of fresh seed at 25°C varied widely between species. Comparisons with tetrazolium viability tests for each species indicated varying levels of dormancy within the species pool. Germination separated into three broad responses at day 28. One-third of the species failed to germinate, one-third germinated at 1% to 50% and the remaining species germinated between 51% and 100%. Therefore, if the aim of a sowing was the rapid and synchronous establishment of most of the sown species, the use of fresh seed in restoration could be problematic. After 3 months of dry storage, eight species were re-tested for germination. Each of the selected species had shown high viability but low initial germination. Only two species significantly increased their total germination at 25°C. The annual species, Triptilodiscus pygmaeus , increased its total germination from 6% as fresh seed to 99% after dry storage. Testing the viability and germination capacity of freshly harvested seed from a large and diverse sample of native grassland species demonstrated that many of the species were unlikely to germinate rapidly or synchronously when sown in complex seed mixes soon after harvest. This finding has implications for the scheduling and management of restoration projects that rely on the use of such seed.     

Post‐Establishment Seedling Success in the Brazilian Cerrado: A Comparison of Savanna and Forest Species1

Due to frequent fire, low nutrient availability, and prolonged drought, tropical savanna is a stressful environment for the survival and growth of woody plant seedlings. To understand why forest species do not succeed in this environment while savanna species are able to persist, the effects of fire and woody cover on seedlings of these two functional groups were investigated in the Brazilian Cerrado. Seedlings were established in experimental plots under three densities of woody cover, in sites protected from fire and sites to be subjected to fire. There was a clear difference in the ability of savanna and forest species to survive fire. None of the three forest species were able to survive fire during the first two years of life, whereas eight of the nine savanna species were able to resprout following fire. The small seed size of the ninth savanna species, Miconia albicans, predisposed its seedlings to be sensitive to fire, because there was a strong positive correlation between seed size and survivorship. Savanna species were less dependent on woody cover than were forest species, which exhibited higher growth and survival under tree canopies than in open grassland. The low rates of establishment and survival of forest trees in savanna, combined with high sensitivity to fire, appear sufficient to prevent the expansion of forest into savanna under current fire regimes in the Cerrado.     

Revegetation to combat tree decline in the Midlands and Derwent Valley Lowlands of Tasmania: Practices for improved plant establishment

Summary The results of site assessment and information survey of 13 plantings established between 1995 and 2000 from the Tasmanian Midlands and Derwent Valley Lowlands are presented. Establishment success of tubestock plantings ranged from 2 to 100% and that of direct seeding from 860 to 20 000 seedlings/ha. Successful establishment of tubestock and direct seeding was associated with first year watering and good rains, respectively. Browsing damage was evident in direct seeded plots with eucalypts most affected and acacias and She-oak ( Allocasuarina verticillata ) least affected. Treeguards appeared to prevent browsing of tubestock, but those poorly constructed by inexperienced planters tended to collapse and smother seedlings. Larger seedlings appeared to exhibit better survival and growth than smaller seedlings under conditions of drought. While only two sites were mounded, mounding appeared superior over ripping as a site preparation technique, particularly where ripping on heavy, black cracking clays induces cracking, drying of the soil profile and seedling mortality when planted too close to rip lines. Recommendations are listed for best practice establishment techniques based on the site assessment and survey results. Of the recommendations, the requirement for postplanting weed control and the benefits of detailed records of plantings are emphasized. Most plantings surveyed would have benefited from postplanting weed control and it is suggested that this has been a major deficiency in previous revegetation programs. Furthermore, there has been little accountability of the success of projects undertaken. Improved record keeping would benefit landholders and particularly extension officers and researchers in the industry.     

Softening the agricultural matrix: a novel agri‐environment scheme that balances habitat restoration and livestock grazing

The loss and degradation of woody vegetation in the agricultural matrix represents a key threat to biodiversity. Strategies for habitat restoration in these landscapes should maximize the biodiversity benefit for each dollar spent in order to achieve the greatest conservation outcomes with scarce funding. To be effective at scale, such strategies also need to account for the opportunity cost of restoration to the farmer. Here, we critique the Whole‐of‐Paddock Rehabilitation program, a novel agri‐environment scheme which seeks to provide a cost‐effective strategy for balancing habitat restoration and livestock grazing. The scheme involves the revegetation of large (minimum 10 ha) fields, designed to maximize biodiversity benefits and minimize costs while allowing for continued agricultural production. The objectives and design of the scheme are outlined, biodiversity and production benefits are discussed, and we contrast its cost‐effectiveness with alternative habitat restoration strategies. Our analysis indicates that this scheme achieves greater restoration outcomes at approximately half the cost of windbreak‐style plantings, the prevailing planting configuration in southeastern Australia, largely due to a focus on larger fields, and the avoidance of fencing costs through the use of existing farm configuration and infrastructure. This emphasis on cost‐effectiveness, the offsetting of opportunity costs through incentive payments, and the use of a planting design that seeks to maximize biodiversity benefits while achieving production benefits to the farmer, has the potential to achieve conservation in productive parts of the agricultural landscape that have traditionally been “off limits” to conservation.     

The merits of artificial selection for the development of restoration‐ready plant materials of native perennial grasses

Although seed harvested from remnant, wildland perennial‐grass populations can be used for restoration in humid and subhumid temperate regions, seed harvested in semiarid and arid environments is often of low quality and highly variable in quantity. In addition, ongoing harvest of indigenous populations can be unsustainable, especially for those that are small. In such environments, dependable and repeatable broad‐scale restoration of degraded grasslands requires sufficient and consistent supplies of reliable, cost‐effective seed sources that can only result from intensively managed cultivated stands. But does the harvest of intensively managed seed‐production fields inadvertently compromise genetic diversity, thereby adversely affecting the restoration outcome? That is, are seed‐production systems a part of the solution for restoration, or do they create new unintended management issues? This article discusses the potential impacts of cultivated seed‐production systems and recurrent artificial selection for specific traits on genetic integrity and performance of native‐species perennial‐grass populations. Although genetic shift resulting from cultivated perennial‐grass seed production may be inevitable, genetic shifts that change phenological expression may be limited in genotypes that exhibit high seed retention. Artificial selection can improve plant material performance on the often‐harsh conditions of restoration sites, but sufficiently high‐effective population sizes (N_e) must be maintained to conserve genetic diversity, thereby precluding the inbreeding depression that can compromise plant performance. Potentially useful traits of native perennial‐grass species that respond to artificial selection include seed production, seed retention, seedling establishment, competitive ability against weeds, and herbicide tolerance. Potential trade‐offs between traits should also be considered to avoid undesirable inadvertent responses to selection.     

Wood‐rotting basidiomycetes associated with declining native trees in timber‐harvesting compartments of the Garden Route National Park of South Africa

Trees in the Garden Route National Park (GRNP) indigenous forests in South Africa are selectively harvested for timber based on criteria that include signs and symptoms induced by wood‐rotting fungi. However, virtually nothing is known regarding the identity and host associations of these macro‐fungi in this natural ecosystem. Surveys were conducted in three harvesting compartments in the GRNP to investigate the taxonomic affiliation and species richness of these fungi on standing and recently harvested trees. Samples were collected from basidiomes on infected trees and tree stumps, and from diseased tissues on symptomatic trees. Phylogenetic analyses using ITS sequences characterized the isolates obtained into 26 Operational Taxonomic Units (OTUs) belonging to 17 genera after clustering the sequences at a 97% identity threshold. Ganoderma (Ganodermataceae) and Inonotus (Hymenochaetaceae) were the most species‐rich genera and the Bloukrans compartment, with 22 OTUs, showed the highest species richness. A fungus (OTU1) affiliated with Ganoderma pfeifferi was the most abundant in the surveyed areas. Its predominance was also evidenced on host trees since it occurred on 15 of the 20 tree species sampled, with Olea capensis subsp. macrocarpa (Oleaceae) being the most colonized host. Given the wide variety of wood‐rotting basidiomycetes revealed by this study and particularly the preponderance of species with pathogenic potential, more attention should be given to better understand their ecological role in this natural ecosystem as well as the effects of logging that may enhance their dissemination or negatively affect their diversity and the health of trees in the region.     

A commensal network of epiphytic orchids and host trees in an Atlantic Forest remnant: A case study revealing the important role of large trees in the network structure

Application of metrics derived from network theory could elucidate the structural organization of orchid assemblages, and help identify the host tree species on which they depend, as well as predicting the impacts of removing host tree species. In this study, we used nestedness, modularity, connectance and robustness, to identify the factors that predict the structure of a quantitative orchid–host tree network in a remnant of Atlantic Forest in Brazil. The network exhibited low nestedness (NODF = 14.07; P = 0.03; WNODF = 5.3; P = 0.02) and no modularity. It was highly robust to the random elimination of host tree species, but showed low robustness when host trees with more interactions started to be eliminated. The nested pattern found was attributed to a combination of two main host tree traits, height and diameter (given by DBH measure). Thus, our analyses reflect the importance of tall and large host tree species, which seem to play an important role in the network structure, providing a substrate for orchid species with different habitat associations and representing a decisive factor in both nested and robust patterns found.     

Direct seeding and outplantings in drylands of Argentinean Patagonia: estimated costs,and prospects for large‐scale restoration and rehabilitation

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.     

Comparisons of population density and genetic diversity in artificial and wild populations of an arborescent coral,Acropora yongei: implications for the efficacy of “artificial spawning hotspots”

We are developing techniques to restore coral populations by enhancing larval supply using “artificial spawning hotspots” that aggregate conspecific adult corals. However, no data were available regarding how natural larval supply from wild coral populations is influenced by fertilization rate and how this is in turn affected by local population density and genetic diversity. Therefore, we assessed population density and genetic diversity of a wild, arborescent coral, Acropora yongei, and compared these parameters with those of an artificially established A. yongei population in the field. The population density of wild arborescent corals was only 0.27% of that in the artificial population, even in a high‐coverage area. Genetic diversity was also low in the wild population compared with the artificial population, and approximately 10% of all wild colonies were clones. Based on these results, the larval supply in the artificial population was estimated to be at least 1,400 times higher than that in wild A. yongei populations for the same area of adult population.