Undertaking large-scale forest restoration to generate ecosystem services

Optimizing restoration: A holistic spatial approach to deliver Nature's Contributions to People with minimal tradeoffs and maximal equity

Ecosystem restoration is inherently a complex activity with inevitable tradeoffs in environmental and societal outcomes. These tradeoffs can potentially be large when policies and practices are focused on single outcomes versus joint achievement of multiple outcomes. Few studies have assessed the tradeoffs in Nature's Contributions to People (NCP) and the distributional equity of NCP from forest restoration strategies. Here, we optimized a defined forest restoration area across India with systematic conservation planning to assess the tradeoffs between three NCP: i) climate change mitigation NCP, ii) biodiversity value NCP (habitat created for forest-dependent mammals), and iii) societal NCP (human direct use of restored forests for livelihoods, housing construction material, and energy). We show that restoration plans aimed at a single-NCP tend not to deliver other NCP outcomes efficiently. In contrast, integrated spatial forest restoration plans aimed at achievement of multiple outcomes deliver on average 83.3% (43.2 to 100%) of climate change mitigation NCP, 89.9% (63.8 to 100%) of biodiversity value NCP, and 93.9% (64.5 to 100%) of societal NCP delivered by single-objective plans. Integrated plans deliver NCP more evenly across the restoration area when compared to other plans that identify certain regions such as the Western Ghats and north-eastern India. Last, 38 to 41% of the people impacted by integrated spatial plans belong to socioeconomically disadvantaged groups, greater than their overall representation in India's population. Moving ahead, effective policy design and evaluation integrating ecosystem protection and restoration strategies can benefit from the blueprint we provide in this study for India.

Effects of seagrass restoration on coastal fish abundance and diversity

Restoration is accelerating to reverse global declines of key habitats and recover lost ecosystem functions, particularly in coastal ecosystems. However, there is high uncertainty about the long-term capacity of restored ecosystems to provide habitat and increase biodiversity and the degree to which these ecosystem services are mediated by spatial and temporal environmental variability. We addressed these gaps by sampling fishes biannually for 5-7 years (2012-2018) at 16 sites inside and outside a rapidly expanding restored seagrass meadow in coastal Virginia (USA). Despite substantial among-year variation in abundance and species composition, seine catches in restored seagrass beds were consistently larger (6.4 times more fish, p < 0.001) and more speciose (2.6 times greater species richness, p < 0.001; 3.1 times greater Hill-Shannon diversity, p = 0.03) than seine catches in adjacent unvegetated areas. Catches were particularly larger during summer than autumn (p < 0.01). Structural equation modeling revealed that depth and water residence time interacted to control seagrass presence, leading to higher fish abundance and richness in shallow, well-flushed areas that supported seagrass. Together, our results indicate that seagrass restoration yields large and consistent benefits for many coastal fishes, but that restoration and its benefits are sensitive to the dynamic seascapes in which restoration is conducted. Consideration of how seascape-scale environmental variability affects the success of habitat restoration and subsequent ecosystem function will improve restoration outcomes and the provisioning of ecosystem services.

Plant functional traits explain long-term differences in ecosystem services between artificial forests and natural grasslands

Declining ecosystem services have prompted numerous studies aiming at developing more sustainable management practices for vegetation restoration. Advances in functional ecology indicate that the sustainable management of afforestation ecosystems should be performed based on plant functional traits, which provides pivotal knowledge for long-term sustainable vegetation restoration. Currently, the mechanism of how plant functional traits affect long term ecosystem services in restored areas is still unclear. This study investigates plant functional traits and the associated ecosystem services from artificial forestlands (Robinia pseudoacacia, Caragana korshinskii) and natural grasslands following different durations of vegetation restoration (10, 20, 30 and 40 years) in the Danangou watershed, a loess hilly-gully region in the Loess Plateau, China. The results showed that 1) the water conservation services of artificial forestlands first decreased and then increased over time, whereas the soil conservation service had an opposite trend; in turn, natural grassland led to a consistent increase in soil conservation and carbon sequestration services over time. 2) Artificial forestlands had greater soil conservation and carbon sequestration services than natural grassland but had lower water conservation services. 3) Leaves had a greater impact on carbon sequestration and water conservation services than did root length and root biomass density. 4) Root biomass density had a greater effect on soil conservation services than did leaf carbon content and soil organic matter. 5) Leaf carbon content, specific root length, and root biomass density had significant effects on the trade-off value between any two ecosystem services with increasing time after restoration of artificial forestland. 6) Specific leaf area had a greater effect on the trade-off values among the three services than did the other functional traits in the natural grassland. In arid ecosystems, natural grasslands are the best restoration strategy given their higher water conservation services. However, in soil erosion-affected areas, restoration through artificial forestlands is more appropriate. To mitigate the trade-offs between ecosystem services, it is recommended that artificial forestlands be thinned before the leaf carbon content, specific root length, and root biomass density reach a maximum (i.e., mature forestland).

Below-ground traits mediate tree survival in a tropical dry forest restoration

Reforestation is one of our most promising natural climate solutions, and one that addresses the looming biodiversity crisis. Tree planting can catalyse forest community reassembly in degraded landscapes where natural regeneration is slow, however, tree survival rates vary remarkably across projects. Building a trait-based framework for tree survival could streamline species selection in a way that generalizes across ecosystems, thereby increasing the effectiveness of the global restoration movement. We investigated how traits mediated seedling survival in a tropical dry forest restoration, and how traits were coordinated across plant structures. We examined growth and survival of 14 species for 2 years and measured six below-ground and 22 above-ground traits. Species-level survival ranged widely from 7.8% to 90.1%, and a model including growth rate, below-ground traits and their interaction explained more than 73% of this variation. A strong interaction between below-ground traits and growth rate indicated that selecting species with fast growth rates can promote establishment, but this effect was most apparent for species that invest in thick fine roots and deep root structures. Overall, results emphasize the prominent role of below-ground traits in determining early restoration outcomes, and highlight little above- and below-ground trait coordination, providing a path forward for tropical dry forest restoration efforts. This article is part of the theme issue 'Understanding forest landscape restoration: reinforcing scientific foundations for the UN Decade on Ecosystem Restoration'.

New approaches: Use of assisted natural succession in revegetation of inhabited arid drylands as alternative to large-scale afforestation

It is a great concept to let nature do the work of revegetation, however in semi-arid and arid regions the process of natural succession, if it occurs at all, typically requires many years of undisturbed development until an increase in biomass becomes measurable, hence it rather is applied to remote, sparsely populated regions and may be underrated as a measure to restore native vegetation, particularly in inhabited arid areas. What are the factors that make arid successional processes successful, how to expedite, and how to enable their use for the ecological revegetation of densely populated drylands? We review restoration methods that combine the planting of shelterbelt compartments with successional revegetation of the internal area, protected from wind and drought. Various measures of assisted natural succession can be applied to greatly accelerate the revegetation, including soil tillage, amendment with organic matter and the inoculation with cyanobacteria or lichens to form biocrusts. The aim is to initiate the development of native, water-saving savanna with biodiversity, resilience and adaptability to climate change. A narrow twin shelterbelt module could facilitate the use of natural succession within inhabited and peri-urban areas, also serving as protective greenbelt for cities. A pilot is planned in a peri-urban area of Northern Iraq, with a successional area of 125–150 m between shelterbelts. Land-use of agriculture, gardening and recreation can be integrated within the successional area, which also generates engagement of residents in the maintenance work. Planting of shelterbelts is required on 10–25% (not 100%) of the restoration area, therefore the use of assisted succession within protective compartments is expected to have both, ecological and economic advantages over large-scale afforestation.

New frontiers in Japanese Forest Policy: Addressing ecosystem disservices in the 21st century

Forests are a potential solution to numerous global environmental issues, and their restoration is widely pursued. Forty percent of Japan's forests are planted forests. This has caused the common occurrence of forest ecosystem disservices in the country, like-wildlife damage, pollinosis, and driftwood damage. Forest policy processes in Japan are characterized by incrementalism, central mobilization, and hegemony of career civil servants. Responses to forest ecosystem disservices have changed the central mobilization policy pattern. Punctuated equilibrium theory can be applied to several policy processes in Japan, but it provides only limited explanation for policy responses to forest ecosystem disservices. The responses are influenced by national governance and public administration traditions and cultures. It is relevant to expand research on policy responses to forest ecosystem disservices, recognizing that ideal responses may require unusual approaches not within traditional policy making or outside of established policy cultures.

The High Cost of the Low-Cost Polybag System: A Review of Nursery Seedling Production Systems

An important strategy for meeting global landscape restoration goals is nursery production of high-quality seedlings. Growing seedlings with attributes that promote post-planting survival and growth can be dramatically influenced by the nursery container system. In many countries, nurseries produce seedlings in polybags filled with excavated soil. These seedlings often develop deformed roots with limited fibrosity which can lead to poor survival and growth after outplanting. Polybags are initially inexpensive but using these single-use plastic containers accrues expenses that are often untracked. Comparisons among nursery production systems must account for factors such as container longevity, labor efficiency, and seedling field performance. A more holistic approach to account for environmental, economic, social, logistic, and cultural elements in the cost–benefit equation that influences nursery production systems is needed. Converting to a modern container system requires concomitant adjustments in nursery scheduling and culturing matched to the new stock type. Doing so provides an opportunity to align nursery production techniques and resulting seedling attributes with anticipated field conditions. This article describes and discusses the advantages and disadvantages of nursery production systems and provides recommendations and case studies to aid nurseries in improving seedling quality toward meeting restoration goals in a cost-effective and timely manner.

China’s Key Forestry Ecological Development Programs: Implementation, Environmental Impact and Challenges

Forest ecosystems are in serious trouble globally, largely due to the over-exploitation. To alleviate environmental problems caused by deforestation, China has undertaken a series of key forestry ecological development programs, including the Natural Forest Protection Program (NFPP), the Conversion of Cropland into Forests Program (CCFP), the Desertification Combating Program around Beijing and Tianjing (DCBT), the Key Shelterbelt Development Programs in the Three-North Region and in the Middle and Lower Reaches of the Yangtze River (KSDP) and the Nature Reserve Development Program in Forestry Sector (WCNR). This article aims to make a documentation of the specific contents (duration, major aims, geographic coverage and investment), and environmental impacts of these programs from peer-reviewed literature, official reports and journals. Environmental impact is measured with land area afforested (except the WCNR) and the consequent changes in ecosystem function. Overall, with the huge investment and long-term efforts, these programs have made tremendous progress in increasing vegetative coverage, enhancing carbon sequestration, controlling soil erosion, conservation of biodiversity, etc. For proper implementation and remarkable achievement, a more balanced approach with flexible planning, suitable measures and proper management should be adopted. Meanwhile, the scientific communities need to be more actively involved in execution and assessment of these programs. The environmental impact of the DCBT, the KSDP, and the WCNR deserve more research concern.

Participatory Assessment of Ecosystem Services from Community-Managed Planted Forests in Bhutan

Planted forests provide a range of ecosystem services, from the local to global scales. In this study, we evaluated the perceptions by local people of the ecosystem services from planted forest stands in Bhutan. We employed household questionnaires, interviews and focus group discussions in eight villages in two regions of Bhutan: Trashigang dzongkhag, in eastern Bhutan, and Punakha dzongkhag in western Bhutan. At all sites, the planted forests were created several decades ago to restore forest cover in deforested and degraded areas. The restored stands were perceived by residents to provide multiple goods and ecosystem services important to local security, health, and livelihoods, including wild edibles, freshwater, and soil protection, and aesthetic and cultural services. This study indicates that local community participation in forest resource management can ease user conflict and manage the planted forests sustainably. We see community-based forest restoration on degraded lands as a viable approach, among others, to achieve national commitments to the Bonn Challenge and other multilateral environmental agreements related to forests.

Partial river flow recovery with forest age is rare in the decades following establishment

Forest regeneration and expansion are occurring in many countries, with 80 million ha established from 2000 to 2012 under the Bonn accord and 17.5 million ha established from 1990 to 2005 according to the Food and Agriculture Organisation. Multiple reviews have linked increasing forest cover with reduced river flow and potentially detrimental effects downstream. Previous reviews have investigated trends in river flow response over time, but the influence of forest age remains uncertain. Partial river flow recovery (towards non-forested conditions) has been reported in decades following forest establishment, but the role of climate in driving these trends has not been explored. Here, we evaluate river flow trends in 43 studies following forest establishment, which provide sufficient information to distinguish the effects of ageing forests from variable climate. Our meta-analysis supports previous findings showing that forestation reduces annual river flow (by 23% after 5 years and 38% after 25 years) with greater reductions in catchments with higher mean annual precipitation, larger increases in forest cover, and which were idle, rather than agricultural land, prior to forestation. The impact of forests on river flow is sensitive to annual precipitation and potential evapotranspiration, but responses are highly variable. Forests affect river flow less when annual precipitation is low, and sensitivity to precipitation decreases as catchment aridity increases. The majority of catchments demonstrated persistent river flow declines after forest establishment. However, nine catchments showed partial flow recovery after an initial decrease, with peak flow reductions at an average age of 15 and across a range of tree species. The mean rate of recovery was 34 mm/year over 5 years. Partial flow recovery with forest age cannot be commonly expected, however, and forestation programmes should take into account that changes to annual river flow are likely to persist for up to five decades.

Narratives Across Scales on Barriers and Strategies for Upscaling Forest Restoration: A Brazilian Case Study

Several countries worldwide have committed to forest and landscape restoration (FLR) through ambitious pledges in numbers of hectares to be restored. As the implementation of these commitments happens within countries, different actors from global to local scales must negotiate the “what, where and how” of specific forest restoration projects. We interviewed actors at national, state and local scales to gather their narratives regarding barriers and strategies for upscaling forest restoration and compared the narratives among them and with those that prevail in the global literature on FLR. We based the local scale in four Atlantic Forest landscapes. We classified the narratives gathered according to three discourses commonly used in environmental policy arenas: (1) ecological modernization, advocating market solutions; (2) green governmentality, with its emphasis on technocratic solutions; and (3) civic environmentalism promoting governance. Brazilian legislation with its mandate of forest restoration in private lands appeared as the main restoration driver in the interviews. However, when political will for enforcement weakens, other strategies are needed. An ecological modernization narrative, around increasing funding, incentives, market and investments, prevailed in the narratives on barriers and strategies for all actors from the global to the local scales. Similarities nevertheless diminished from the global to the local scale. The narratives of national actors resembled those found in the global literature, which emphasize strategies based on increased capacity building, within a green governmentality narrative, and governance arrangements, a civic environmentalist narrative. These narratives appeared less at state scales, and were almost absent at local scales where forest restoration was perceived mostly as a costly legal mandate. Similar narratives across all actors and scales indicate that a focus on improving the economics of restoration can aid in upscaling forest restoration in Brazilian Atlantic Forest landscapes. However, discrepant narratives also show that inclusive governance spaces where the negotiation of FLR interventions can take place is key to increase trust and aid implementation.

Conserving plants within and beyond protected areas - still problematic and future uncertain

Against a background of continuing loss of biodiversity, it is argued that for the successful conservation of threatened plant species we need to ensure the more effective integration of the various conservation actions employed, clarify the wording of the CBD targets and provide clearer operational guidance as to how they are to be implemented and their implementation monitored. The role and effectiveness of protected areas in conserving biodiversity and in particular plant species in situ are discussed as are recent proposals for a massive increase of their extent. The need for much greater effort and investment in the conservation or protection of threatened species outside protected areas where most plant diversity occurs is highlighted. The difficulties involved in implementing effective in situ conservation of plant diversity both at an area- and species/population-based level are discussed. The widespread neglect of species recovery for plants is noted and the desirability of making a clearer distinction between species recovery and reintroduction is emphasized. Key messages from a global overview of species recovery are outlined and recommendations made, including the desirability of each country preparing a national species recovery strategy. The projected impacts of global change on protected areas and on species conservation and recovery, and ways of addressing them are discussed.

Recovering threatened plant species and their habitats: The need for integrated action

As an introduction to the Special Issue on the restoration of threatened plant species and their habitats, this editorial shows how the various papers in the issue address the range of in situ interventions involved in species population management and restoration of their habitat, together with examples of case studies implementing these actions. It stresses the need for integrating these various interventions. It highlights the importance of protected areas in providing a degree of protection for threatened species but also the need to complement this with actions at the species level to ensure the effective conservation and long term persistence of these species. It emphasizes that ecological restoration is a complement to, not a substitute for conservation, and that the balance of effort and allocation of resources between them is a key issue.

Intensive silviculture enhances biomass accumulation and tree diversity recovery in tropical forest restoration

Maximizing initial aboveground woody biomass (AGB) accumulation in order to obtain early payments for carbon stocking is essential for the financial viability of reforestation programs fostered by climate mitigation efforts. Intensive silviculture, i.e., silviculture traditionally used in commercial forestry to maximize productivity and gains, has recently been advocated as a promising approach to enhance AGB accumulation in restoration plantations. However, this approach may hamper natural forest regeneration and ecological succession due to high competition between colonizing plants and planted trees. We investigated the impacts of different silvicultural treatments applied to restoration plantations with 20 native tree species on AGB accumulation and spontaneous regeneration of native woody species in an experiment set up in the Atlantic Forest of Brazil. Intensive silviculture demonstrated a remarkable potential to enhance AGB accumulation in restoration plantations by increasing up to three times the AGB of tree stands (from ~25 to 75 Mg/ha in the 12th year). Intensive fertilization/weed control enhanced AGB accumulation, while higher tree density and the proportion of pioneers did not have a significant effect on AGB over the time. In spite of higher costs (cost increase of 13-19%), the cost-effectiveness for AGB accumulation of intensive silviculture was comparable to that of traditional silviculture applied to restoration (US$50-100/Mg AGB for 3 × 2 m spacing). Contrary to our expectations, we did not find a trade-off between AGB accumulation by planted trees and the spontaneous regeneration of tree species, since intensive silviculture enhanced the regeneration of both planted (total of 12 species) and colonizing woody species (total of 30 species) in the plantation understory. Specifically, a strong association was found between AGB stocks and the abundance and richness of colonizing species, a vast majority of which (90% of species and 95% of individuals) were dispersed by animals. We report a case of positive correlation between AGB stocking and woody species regeneration in the restoration of the Atlantic Forest. Fostering the establishment and maintenance of restoration tree plantations can, in some cases, be a win-win strategy for climate mitigation and biodiversity conservation in human-modified tropical landscapes.