Forest restoration

From Wikipedia, the free encyclopedia

 

In the 1980s, conservation organizations warned that, once destroyed, tropical forests could never be restored. Thirty years of restoration research now challenge this: a) This site in Doi Suthep-Pui National Park, N. Thailand was deforested, over-cultivated and then burnt. The black tree stump was one of the original forest trees. Local people teamed up with scientists to repair their watershed.

 

Fire prevention, nurturing natural regeneration and planting framework tree species resulted in trees growing above the weed canopy within a year.

 

After 12 years, the restored forest overwhelmed the black tree stump.

Forest restoration is defined as “actions to re-instate ecological processes, which accelerate recovery of forest structure, ecological functioning and biodiversity levels towards those typical of climax forest” i.e. the end-stage of natural forest succession. Climax forests are relatively stable ecosystems that have developed the maximum biomass, structural complexity and species diversity that are possible within the limits imposed by climate and soil and without continued disturbance from humans. Climax forest is therefore the target ecosystem, which defines the ultimate aim of forest restoration. Since climate is a major factor that determines climax forest composition, global climate change may result in changing restoration aims.

Forest restoration is a specialized form of reforestation, but it differs from conventional tree plantations in that its primary goals are biodiversity recovery and environmental protection.

Scope

Forest restoration may include simply protecting remnant vegetation (fire prevention, cattle exclusion etc.) or more active interventions to accelerate natural regeneration, as well as tree planting and/or sowing seeds (direct seeding) of species characteristic of the target ecosystem. Tree species planted (or encouraged to establish) are those that are typical of, or provide a critical ecological function in, the target ecosystem. However, wherever people live in or near restoration sites, restoration projects often include economic species amongst the planted trees, to yield subsistence or cash-generating products. 

Forest restoration is an inclusive process, which depends on collaboration among a wide range of stakeholders including local communities, government officials, non-government organizations, scientists and funding agencies. Its ecological success is measured in terms of increased biological diversity, biomass, primary productivity, soil organic matter and water-holding capacity, as well as the return of rare and keystone species, characteristic of the target ecosystem. Economic indices of success include the value of forest products and ecological services generated (e.g. watershed protection, carbon storage etc.), which ultimately contribute towards poverty reduction. Payments for such ecological services (PES) and forest products can provide strong incentives for local people to implement restoration projects.

Opportunities for forest restoration

Demonstration forest restoration plot, SUNY-ESF, Syracuse, NY

 

Forest restoration is appropriate wherever biodiversity recovery is one of the main goals of reforestation, such as for wildlife conservation, environmental protection, eco-tourism or to supply a wide variety of forest products to local communities. Forests can be restored in a wide range of circumstances, but degraded sites within protected areas are a high priority, especially where some climax forest remains as a seed source within the landscape. Even in protected areas, there are often large deforested sites: logged over areas or sites formerly cleared for agriculture. If protected areas are to act as Earth’s last wildlife refuges, restoration of such areas will be needed.

Many restoration projects are now being implemented under the umbrella of “forest landscape restoration” (FLR), defined as a “planned process to regain ecological integrity and enhance human well-being in deforested or degraded landscapes”. FLR recognizes that forest restoration has social and economic functions. It aims to achieve the best possible compromise between meeting both conservation goals and the needs of rural communities. As human pressure on landscapes increases, forest restoration will most commonly be practiced within a mosaic of other forms of forest management, to meet the economic needs of local people. 

A recent focal area for forest restoration efforts is within the urban context, where both people and biodiversity will benefit, however this context presents unique challenges.

Natural regeneration

Tree planting is not always essential to restore forest ecosystems. A lot can be achieved by studying how forests regenerate naturally, identifying the factors that limit regeneration and devising methods to overcome them. These can include weeding and adding fertilizer around natural tree seedlings, preventing fire, removing cattle and so on. This is "accelerated" or "assisted" natural regeneration. It is simple and cost-effective, but it can only operate on trees that are already present, mostly light-loving pioneer species. Such tree species are not usually those that comprise climax forests, but they can foster recolonization of the site by shade-tolerant climax forest tree species, via natural seed dispersal from remnant forest. Because this is a slow process, biodiversity recovery can usually be accelerated by planting some climax forest tree species, especially large-seeded, poorly dispersed species. It is not feasible to plant all the tree species that may have formerly grown in the original primary forest and it is usually unnecessary to do so, if the framework species method can be used.

Post-fire regeneration

In large parts of the world, forest fires cover a heavy toll on forests. That can be because of provoked deforestation in order to substitute forests by crop areas, or in dry areas, because of wild fires occurring naturally or intentionally. A whole section of forest landscape restoration in linked to this particular problem, as in many cases, the net loss of ecosystem value is very high and can open the drop to an accelerated further degradation of the soil conditions through erosion and desertification. This indeed has dire consequences on both the quality of the habitats and their related fauna. Nevertheless, in some specific cases, wild fires do actually allow to increase the biodiversity index of the burnt area, in which case the Forest Restoration Strategies tend to look for a different land-use.

Forest restoration projects

Ashland Forest Resiliency Stewardship Project

The Ashland Forest Resiliency Stewardship Project (AFR) is a decade long, science-based project launched in 2010 with the intent of reducing severe wildfire risk, but also protecting water quality, old-growth forest, wildlife, people, property, and the overall quality of life within the Ashland watershed. The primary stakeholders in this cooperative restoration effort are the U.S. Forest Service, the City of Ashland, Lomaktsi Restoration Project, and the Nature Conservancy. The project was launched with initial funding from the Economic Recovery stimulus, and has more recently received funding from the Forest Service Hazardous Fuels program and the Joint Chiefs Landscape Restoration Partnerships program to back the project through 2016.

Located in the dry forests of southern Oregon, the threat of wildfire is a reality for land managers and property owners alike. The boundaries of the city of Ashland intersect with the surrounding forest in what is referred to as the wildland-urban interface (WUI). Historically, the forests of this region experienced a relatively frequent fire return interval, which prevented buildup of heavy fuel loads. A century of fire exclusion and suppression on federal lands in the Pacific Northwest has led to increased forest density and fuel loads, and thus a more persistent threat of devastating wildfire.

The AFR project has implemented restoration techniques and prescriptions that aim to replicate the process of ecological succession in dry, mixed-conifer forests of the Pacific Northwest. The approach involves a combination of fuels reduction, thinning small-diameter trees, and carrying out prescribed burns. Priority is given to maintaining ecological function and complexity by retaining the largest and oldest trees, preserving wildlife habitat and riparian areas, and protecting erodible soils and maintaining slope stability. 

Since its inception in 2010, the AFR project has completed restoration work on 4,000 of the 7,600 acres slated for the project. The project has provided educational experience to over 2,000 students and has benefitted the local community by creating jobs and providing workforce training. Currently, helicopter logging operations are thinning 1,100 acres of the watershed while controlled burning operations take place as air quality conditions allow.

Forest landscape restoration

Forest landscape restoration (FLR) is defined as “a planned process to regain ecological integrity and enhance human well-being in deforested or degraded landscapes”. It comprises tools and procedures to integrate site-level forest restoration actions with desirable landscape-level objectives, which are decided upon via various participatory mechanisms among stakeholders. The concept has grown out of collaboration among some of the world's major international conservation organizations including the International Union for Conservation of Nature (IUCN), the World Wide Fund for Nature (WWF), the World Resources Institute and the International Tropical Timber Organization (ITTO).

Aims

The concept of FLR was conceived to bring about compromises between meeting the needs of both humans and wildlife, by restoring a range of forest functions at the landscape level. It includes actions to strengthen the resilience and ecological integrity of landscapes and thereby keep future management options open. The participation of local communities is central to the concept, because they play a critical role in shaping the landscape and gain significant benefits from restored forest resources. Therefore, FLR activities are inclusive and participatory.

Desirable outcomes

The desirable outcomes of an FLR program usually comprise a combination of the following, depending on local needs and aspirations:

• identification of the root causes of forest degradation and prevention of further deforestation,
• positive engagement of people in the planning of forest restoration, resolution of land-use conflicts and agreement on benefit-sharing systems,
• compromises over land-use trade-offs that are acceptable to the majority of stakeholders,
• a repository of biological diversity of both local and global value,
• delivery of a range of utilitarian benefits to local communities including:
  • a reliable supply of clean water,
  • environmental protection particularly watershed services (e.g. reduced soil erosion, lower landslide risk, flood/drought mitigation etc.),
  • a sustainable supply of a diverse range of forest products including foods, medicines, firewood etc.,
  • monetary income from various sources e.g. ecotourism, carbon trading via the REDD+ mechanism and from payments for other environmental services (PES)

Activities

FLR combines several existing principles and techniques of development, conservation and natural resource management, such as landscape character assessment, participatory rural appraisal, adaptive management etc. within a clear and consistent evaluation and learning framework. An FLR program may comprise various forestry practices on different sites within the landscape, depending on local environmental and socioeconomic factors. These may include protection and management of secondary and degraded primary forests, standard forest restoration techniques such as "assisted" or "accelerated" natural regeneration (ANR) and the planting of framework tree species to restore degraded areas, as well as conventional tree plantations and agroforestry systems to meet more immediate monetary needs.

 

The IUCN hosts the Global Partnership on Forest Landscape Restoration, which co-ordinates development of the concept around the world. 

In 2014, the Food and Agricultural Organization of the United Nations established the Forest and Landscape Restoration Mechanism. The Mechanism supports countries to implement FLR as a contribution to achieving the Bonn Challenge - the restoration of 150 million hectare of deforested and degraded lands by 2020 - and the Convention on Biological Diversity Aichi Biodiversity Targets - related to ecosystem conservation and restoration. 

In partnership with the Global Mechanism of the United Nations Convention to Combat Desertification, FAO released two discussion papers on sustainable financing for FLR in 2015. Sustainable Financing for Forest and Landscape Restoration: The Role of Public Policy Makers provides recommendations and examples of FLR financing for countrues. Sustainable Financing for Forest and Landscape Restoration - Opportunities, challenges and the way forward provides an overview of funding sources and financial instruments available for FLR activities.

Restoration ecology

From Wikipedia, the free encyclopedia

 

Recently constructed wetland regeneration in Australia, on a site previously used for agriculture

 

Rehabilitation of a portion of Johnson Creek, to restore bioswale and flood control functions of the land which had long been converted to pasture for cow grazing. The horizontal logs can float, but are anchored by the posts. Just-planted trees will eventually stabilize the soil. The fallen trees with roots jutting into the stream are intended to enhance wildlife habitat. The meandering of the stream is enhanced here by a factor of about three times, perhaps to its original course.

 

Restoration ecology is the scientific study supporting the practice of ecological restoration, which is the practice of renewing and restoring degraded, damaged, or destroyed ecosystems and habitats in the environment by active human intervention and action. 

Natural ecosystems provide ecosystem services in the form of resources such as food, fuel, and timber; the purification of air and water; the detoxification and decomposition of wastes; the regulation of climate; the regeneration of soil fertility; and the pollination of crops. These ecosystem processes have been estimated to be worth trillions of dollars annually. There is consensus in the scientific community that the current environmental degradation and destruction of many of the Earth's biota is taking place on a "catastrophically short timescale". Scientists estimate that the current species extinction rate, or the rate of the Holocene extinction, is 1,000 to 10,000 times higher than the normal, background rate. Habitat loss is the leading cause of both species extinctions and ecosystem service decline. Two methods have been identified to slow the rate of species extinction and ecosystem service decline, they are the conservation of currently viable habitat, and the restoration of degraded habitat. The commercial applications of ecological restoration have increased exponentially in recent years. The United Nations General Assembly (01.03.2019) declared 2021 – 2030 the UN Decade on Ecosystem Restoration 

Definition

Restoration ecology is the academic study of the process, whereas ecological restoration is the actual project or process by restoration practitioners. The Society for Ecological Restoration defines "ecological restoration" as an "intentional activity that initiates or accelerates the recovery of an ecosystem with respect to its health, integrity and sustainability". Ecological restoration includes a wide scope of projects including erosion control, reforestation, removal of non-native species and weeds, revegetation of disturbed areas, daylighting streams, reintroduction of native species (preferably native species that have local adaptation), and habitat and range improvement for targeted species.

E. O. Wilson, a biologist, states, "Here is the means to end the great extinction spasm. The next century will, I believe, be the era of restoration in ecology."

History

Restoration ecology emerged as a separate field in ecology in the late twentieth century. The term was coined by John Aber and William Jordan III when they were at the University of Wisconsin–Madison. However, indigenous peoples, land managers, stewards, and laypeople have been practicing ecological restoration or ecological management for thousands of years.

Considered the birthplace of modern ecological restoration, the first tallgrass prairie restoration was the 1936 Curtis Prairie at the University of Wisconsin–Madison Arboretum. Civilian Conservation Corps workers replanted nearby prairie species onto a former horse pasture, overseen by university faculty including renowned ecologist Aldo Leopold, botanist Theodore Sperry, mycologist Henry C. Greene, and plant ecologist John T. Curtis. Curtis and his graduate students surveyed the whole of Wisconsin, documenting native species communities and creating the first species lists for tallgrass restorations. Existing prairie remnants, such as locations within pioneer cemeteries and railroad rights-of-way, were located and inventoried by Curtis and his team. The UW Arboretum was the center of tallgrass prairie research through the first half of the 20th century, with the development of the nearby Greene Prairie, Aldo Leopold Shack and Farm, and pioneering techniques like prescribed burning.

The latter-half of the 20th century saw the growth of ecological restoration beyond Wisconsin borders. The 285-hectare Green Oaks Biological Field Station at Knox College began in 1955 under the guidance of zoologist Paul Shepard. It was followed by the 40-hectare Schulenberg Prairie at the Morton Arboretum, started in 1962 by Ray Schulenberg and Bob Betz. Betz then worked with The Nature Conservancy to establish the 260-hectare Fermi National Laboratory tallgrass prairie in 1974. These major tallgrass restoration projects marked the growth of ecological restoration from isolated studies to widespread practice.

Australia has also been the site of historically significant ecological restoration projects. In 1935 Ambrose Crawford commenced restoring a degraded four acres (1.7 hectares) patch of the Big Scrub (Lowland Tropical Rainforest) at Lumley Park reserve, Alstonville, in northern New South Wales. Clearing of weeds and planting of suitable indigenous flora species were his main restoration techniques. The restored rainforest reserve still exists today and is home to threatened plant and animal species. In 1936 Albert Morris and his restoration colleagues initiated the Broken Hill regeneration area project, which involved the natural regeneration of indigenous flora on a severely degraded site of hundreds of hectares in arid western New South Wales. Completed in 1958, the successful project still maintains ecological function today as the Broken Hill Regeneration Area.

Theoretical foundations

Restoration ecology draws on a wide range of ecological concepts.

Disturbance

Disturbance is a change in environmental conditions that disrupts the functioning of an ecosystem. Disturbance can occur at a variety of spatial and temporal scales, and is a natural component of many communities. For example, many forest and grassland restorations implement fire as a natural disturbance regime. However the severity and scope of anthropogenic impact has grown in the last few centuries. Differentiating between human-caused and naturally occurring disturbances is important if we are to understand how to restore natural processes and minimize anthropogenic impacts on the ecosystems.

Succession

Ecological succession is the process by which a community changes over time, especially following a disturbance. In many instances, an ecosystem will change from a simple level of organization with a few dominant pioneer species to an increasingly complex community with many interdependent species. Restoration often consists of initiating, assisting, or accelerating ecological successional processes, depending on the severity of the disturbance. Following mild to moderate natural and anthropogenic disturbances, restoration in these systems involves hastening natural successional trajectories through careful management. However, in a system that has experienced a more severe disturbance (such as in urban ecosystems), restoration may require intensive efforts to recreate environmental conditions that favor natural successional processes.

Fragmentation

Habitat fragmentation describes spatial discontinuities in a biological system, where ecosystems are broken up into smaller parts through land use changes (e.g. agriculture) and natural disturbance. This both reduces the size of the populations and increases the degree of isolation. These smaller and isolated populations are more vulnerable to extinction. Fragmenting ecosystems decreases quality of the habitat. The edge of a fragment has a different range of environmental conditions and therefore supports different species than the interior. Restorative projects can increase the effective size of a population by adding suitable habitat and decrease isolation by creating habitat corridors that link isolated fragments. Reversing the effects of fragmentation is an important component of restoration ecology.

Ecosystem function

Ecosystem function describes the most basic and essential foundational processes of any natural systems, including nutrient cycles and energy fluxes. An understanding of the complexity of these ecosystem functions is necessary to address any ecological processes that may be degraded. Ecosystem functions are emergent properties of the system as a whole, thus monitoring and management are crucial for the long-term stability of ecosystems. A fully functional ecosystem that is completely self-perpetuating is the ultimate goal of restorative efforts. We must understand what ecosystem properties influence others to restore desired functions and reach this goal.

Community assembly

Community assembly "is a framework that can unify virtually all of (community) ecology under a single conceptual umbrella". Community assembly theory attempts to explain the existence of environmentally similar sites with differing assemblages of species. It assumes that species have similar niche requirements, so that community formation is a product of random fluctuations from a common species pool. Essentially, if all species are fairly ecologically equivalent, then random variation in colonization, and migration and extinction rates between species, drive differences in species composition between sites with comparable environmental conditions.

Population genetics

Genetic diversity has shown to be as important as species diversity for restoring ecosystem processes. Hence ecological restorations are increasingly factoring genetic processes into management practices. Population genetic processes that are important to consider in restored populations include founder effects, inbreeding depression, outbreeding depression, genetic drift, and gene flow. Such processes can predict whether or not a species successfully establishes at a restoration site.

Applications

Soil heterogeneity effects on community heterogeneity

Spatial heterogeneity of resources can influence plant community composition, diversity, and assembly trajectory. Baer et al. (2005) manipulated soil resource heterogeneity in a tallgrass prairie restoration project. They found increasing resource heterogeneity, which on its own was insufficient to insure species diversity in situations where one species may dominate across the range of resource levels. Their findings were consistent with the theory regarding the role of ecological filters on community assembly. The establishment of a single species, best adapted to the physical and biological conditions can play an inordinately important role in determining the community structure.

Invasion and restoration

Restoration is used as a tool for reducing the spread of invasive plant species in a number of ways. The first method views restoration primarily as a means to reduce the presence of invasive species and limit their spread. As this approach emphasizes control of invaders, the restoration techniques can differ from typical restoration projects. The goal of such projects is not necessarily to restore an entire ecosystem or habitat. These projects frequently use lower diversity mixes of aggressive native species seeded at high density. They are not always actively managed following seeding. The target areas for this type of restoration are those which are heavily dominated by invasive species. The goals are to first remove the species and then in so doing, reduce the number of invasive seeds being spread to surrounding areas. An example of this is through use of biological control agents (such as herbivorous insects) which suppress invasive weed species while restoration practitioners concurrently seed in native plant species that take advantage of the freed resources. These approaches have been shown to be effective in reducing weeds, although it is not always a sustainable solution long term without additional weed control, such as mowing, or re-seeding.

Restoration projects are also used as a way to better understand what makes an ecological community resistant to invasion. As restoration projects have a broad range of implementation strategies and methods used to control invasive species, they can be used by ecologists to test theories about invasion. Restoration projects have been used to understand how the diversity of the species introduced in the restoration affects invasion. We know that generally higher diversity prairies have lower levels of invasion. Incorporation of functional ecology has shown that more functionally diverse restorations have lower levels of invasion. Furthermore, studies have shown that using native species functionally similar to invasive species are better able to compete with invasive species. Restoration ecologists have also used the variety of strategies employed at different restoration sites to better understand the most successful management techniques to control invasion.

Successional trajectories

Progress along a desired successional pathway may be difficult if multiple stable states exist. Looking over 40 years of wetland restoration data, Klötzli and Gootjans (2001) argue that unexpected and undesired vegetation assemblies "may indicate that environmental conditions are not suitable for target communities". Succession may move in unpredicted directions, but constricting environmental conditions within a narrow range may rein in the possible successional trajectories and increase the likelihood of a desired outcome.

Sourcing material for restoration

For most restoration projects it is generally recommend to source material from local populations, to increase chance of restoration success and minimize the effects of maladaptation. However the definition of local can vary based on species. habitat and region. US Forest Service recently developed provisional seed zones based on a combination of minimum winter temperature zones, aridity, and the Level III ecoregions. Rather than putting strict distance recommendations, other guidelines recommend sourcing seeds to match similar environmental conditions. For example, sourcing for Castilleja levisecta found that farther source populations that matched similar environmental variables were better suited for the restoration project than closer source populations.

Principles

Ecosystem restoration for the superb parrot on an abandoned railway line in Australia

Rationale

There are many reasons to restore ecosystems. Some include:

• Restoring natural capital such as drinkable water or wildlife populations
• Helping human communities and the ecosystems upon which they depend adapt to the impacts of climate change (through ecosystem-based adaptation)
• Mitigating climate change (e.g. through carbon sequestration)
• Helping threatened or endangered species
• Aesthetic reasons 
• Moral reasons: human intervention has unnaturally destroyed many habitats, and there exists an innate obligation to restore these destroyed habitats
• Regulated use/harvest, particularly for subsistence
• Cultural relevance of native ecosystems to Native people
• Environmental health of nearby populations 

Forest restoration in action at the Buffelsdraai Landfill Site Community Reforestation Project in South Africa

 

There exist considerable differences of opinion in how to set restoration goals and how to define their success among conservation groups. Some urge active restoration (e.g. eradicating invasive animals to allow the native ones to survive) and others who believe that protected areas should have the bare minimum of human interference, such as rewilding. Ecosystem restoration has generated controversy. Skeptics doubt that the benefits justify the economic investment or who point to failed restoration projects and question the feasibility of restoration altogether. It can be difficult to set restoration goals, in part because, as Anthony Bradshaw claims, "ecosystems are not static, but in a state of dynamic equilibrium…. [with restoration] we aim [for a] moving target." 

Some conservationists argue that, though an ecosystem may not be returned to its original state, the functions of the ecosystem (especially ones that provide services to us) may be more valuable in its current configuration (Bradshaw 1987). This is especially true in cases where the ecosystem services are central to the physical and cultural survival of human populations, as is the case with many Native groups in the United States and other communities around the world who subsist using ecological services and environmental resources. One reason to consider ecosystem restoration is to mitigate climate change through activities such as afforestation. Afforestation involves replanting forests, which remove carbon dioxide from the air. Carbon dioxide is a leading cause of global warming (Speth, 2005) and capturing it would help alleviate climate change. Another example of a common driver of restoration projects in the United States is the legal framework of the Clean Water Act, which often requires mitigation for damage inflicted on aquatic systems by development or other activities.

Restored prairie at the West Eugene Wetlands in Eugene, Oregon.

Challenges

Some view ecosystem restoration as impractical, partially because restorations often fall short of their goals. Hilderbrand et al. point out that many times uncertainty (about ecosystem functions, species relationships, and such) is not addressed, and that the time-scales set out for 'complete' restoration are unreasonably short, while other critical markers for full-scale restoration are either ignored or abridged due to feasibility concerns. In other instances an ecosystem may be so degraded that abandonment (allowing a severely degraded ecosystem to recover on its own) may be the wisest option. Local communities sometimes object to restorations that include the introduction of large predators or plants that require disturbance regimes such as regular fires, citing threat to human habitation in the area. High economic costs can also be perceived as a negative impact of the restoration process. 

Public opinion is very important in the feasibility of a restoration; if the public believes that the costs of restoration outweigh the benefits they will not support it.

Many failures have occurred in past restoration projects, many times because clear goals were not set out as the aim of the restoration, or an incomplete understanding of the underlying ecological framework lead to insufficient measures. This may be because, as Peter Alpert says, "people may not [always] know how to manage natural systems effectively". Furthermore, many assumptions are made about myths of restoration such as carbon copy, where a restoration plan, which worked in one area, is applied to another with the same results expected, but not realized.

Science-practice gap

One of the struggles for both fields is a divide between restoration ecology and ecological restoration in practice. Many restoration practitioners as well as scientists feel that science is not being adequately incorporated into ecological restoration projects. In a 2009 survey of practitioners and scientists, the "science-practice gap" was listed as the second most commonly cited reason limiting the growth of both science and practice of restoration.

There are a variety of theories about the cause of this gap. However, it has been well established that one of the main issues is that the questions studied by restoration ecologists are frequently not found useful or easily applicable by land managers. For instance, many publications in restoration ecology characterize the scope of a problem in depth, without providing concrete solutions. Additionally many restoration ecology studies are carried out under controlled conditions and frequently at scales much smaller than actual restorations. Whether or not these patterns hold true in an applied context is often unknown. There is evidence that these small-scale experiments inflate type II error rates and differ from ecological patterns in actual restorations.

There is further complication in that restoration ecologists who want to collect large-scale data on restoration projects can face enormous hurdles in obtaining the data. Managers vary in how much data they collect, and how many records they keep. Some agencies keep only a handful of physical copies of data that make it difficult for the researcher to access. Many restoration projects are limited by time and money, so data collection and record keeping are not always feasible. However, this limits the ability of scientists to analyze restoration projects and give recommendations based on empirical data.

Contrasting restoration ecology and conservation biology

Restoration ecology may be viewed as a sub-discipline of conservation biology, the scientific study of how to protect and restore biodiversity. Ecological restoration is then a part of the resulting conservation movement.

Both restoration ecologists and conservation biologists agree that protecting and restoring habitat is important for protecting biodiversity. However, conservation biology is primarily rooted in population biology. Because of that, it is generally organized at the population genetic level and assesses specific species populations (i.e. endangered species). Restoration ecology is organized at the community level, which focuses on broader groups within ecosystems.

In addition, conservation biology often concentrates on vertebrate animals because of their salience and popularity, whereas restoration ecology concentrates on plants. Restoration ecology focuses on plants because restoration projects typically begin by establishing plant communities. Ecological restoration, despite being focused on plants, may also have "poster species" for individual ecosystems and restoration projects. For example, the Monarch butterfly is a poster species for conserving and restoring milkweed plant habitat, because Monarch butterflies require milkweed plants to reproduce. Finally, restoration ecology has a stronger focus on soils, soil structure, fungi, and microorganisms because soils provide the foundation of functional terrestrial ecosystems.

Natural Capital Committee's recommendation for a 25-year plan

The UK Natural Capital Committee (NCC) made a recommendation in its second State of Natural Capital report published in March 2014 that in order to meet the Government's goal of being the first generation to leave the environment in a better state than it was inherited, a long-term 25-year plan was needed to maintain and improve England's natural capital. The UK Government has not yet responded to this recommendation. 

The Secretary of State for the UK's Department for Environment, Food and Rural Affairs, Owen Paterson, described his ambition for the natural environment and how the work of the Committee fits into this at an NCC event in November 2012: "I do not, however, just want to maintain our natural assets; I want to improve them. I want us to derive the greatest possible benefit from them, while ensuring that they are available for generations to come. This is what the NCC's innovative work is geared towards".

Acrylamide

From Wikipedia, the free encyclopedia

 

Acrylamide

Names
Preferred IUPAC name Prop-2-enamide
Other names Acrylamide Acrylic amide
Identifiers
CAS Number	79-06-1
3D model (JSmol)	Interactive image Interactive image
ChEBI	CHEBI:28619
ChEMBL	ChEMBL348107
ChemSpider	6331
ECHA InfoCard	100.001.067
IUPHAR/BPS	4553
KEGG	C01659
PubChem CID	6579
UNII	20R035KLCI
CompTox Dashboard (EPA)	DTXSID5020027
InChI[show]
SMILES[show]
Properties
Chemical formula	C3H5NO
Molar mass	71.079 g·mol−1
Appearance	white crystalline solid, no odor
Density	1.322 g/cm3
Melting point	84.5 °C (184.1 °F; 357.6 K)
Boiling point	None (polymerization); decomposes at 175-300°C
Solubility in water	2.04 kg/L (25 °C)
Hazards
Main hazards	potential occupational carcinogen
Safety data sheet	ICSC 0091
GHS pictograms
GHS hazard statements	H301, H312, H315, H317, H319, H332, H340, H350, H361, H372
GHS precautionary statements	P201, P280, P301+310, P305+351+338, P308+313
NFPA 704	2 3 2
Flash point	138 °C (280 °F; 411 K)
Autoignition temperature	424 °C (795 °F; 697 K)
Lethal dose or concentration (LD, LC):
LD50 (median dose)	100-200 mg/kg (mammal, oral) 107 mg/kg (mouse, oral) 150 mg/kg (rabbit, oral) 150 mg/kg (guinea pig, oral) 124 mg/kg (rat, oral)
US health exposure limits (NIOSH):
PEL (Permissible)	TWA 0.3 mg/m3 [skin]
REL (Recommended)	Ca TWA 0.03 mg/m3 [skin]
IDLH (Immediate danger)	60 mg/m3
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Acrylamide (or acrylic amide) is an organic compound with the chemical formula CH₂=CHC(O)NH₂. It is a white odorless solid, soluble in water and several organic solvents. It is produced industrially as a precursor to polyacrylamides, which find many uses as water-soluble thickeners and flocculation agents. It is highly toxic, likely to be carcinogenic, and partly for that reason it is mainly handled as an aqueous solution.

The discovery that some cooked foods contain acrylamide in 2002 attracted significant attention to its possible biological effects. As of 2019 epidemiological studies suggest it is unlikely that acrylamide consumption increases people's risk of developing cancer.

Production

Acrylamide can be prepared by the hydrolysis of acrylonitrile. The reaction is catalyzed by sulfuric acid as well as various metal salts. It is also catalyzed by the enzyme nitrile hydratase. US demand for acrylamide was 253,000,000 pounds (115,000,000 kg) as of 2007, increased from 245,000,000 pounds (111,000,000 kg) in 2006. 

N-(D-glucos-1-yl)-L-asparagine, precursor to acrylamide in cooked food.

 

Acrylamide arises in some cooked foods via a series of steps initiated by the condensation of the amino acid asparagine and glucose. This condensation, one of the Maillard reactions followed by dehydrogenation produces N-(D-glucos-1-yl)-L-asparagine, which upon pyrolysis generates some acrylamide.

Uses

The majority of acrylamide is used to manufacture various polymers, especially polyacrylamide used as a thickening agent and in water treatment.

Toxicity and carcinogenicity

U.S. regulation

Acrylamide is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.

Acrylamide is considered a potential occupational carcinogen by U.S. government agencies and classified as a Group 2A carcinogen by the IARC. The Occupational Safety and Health Administration and the National Institute for Occupational Safety and Health have set dermal occupational exposure limits at 0.03 mg/m³ over an eight-hour workday. In animal models, exposure to acrylamide causes tumors in the adrenal glands, thyroid, lungs, and testes. Acrylamide is easily absorbed by the skin and distributed throughout the organism; the highest levels of acrylamide post-exposure are found in the blood, non-exposed skin, kidneys, liver, testes, and spleen. Acrylamide can be metabolically-activated by cytochrome P450 to a genotoxic metabolite, glycidamide, which is considered to be a critical mode of action to the carcinogenesis of acrylamide. On the other hand, acrylamide and glycidamide can be detoxified via conjugation with glutathione to form acrylamide- and isomeric glycidamide-glutathione conjugates, subsequently metabolized to mercapturic acids and excreted in urine. Acrylamide has also been found to have neurotoxic effects in humans who have been exposed. Animal studies show neurotoxic effects as well as mutations in sperm.

Hazards

Acrylamide is also a skin irritant and may be a tumor initiator in the skin, potentially increasing risk for skin cancer. Symptoms of acrylamide exposure include dermatitis in the exposed area, and peripheral neuropathy.

Laboratory research has found that some phytochemicals may have the potential to be developed into drugs which could alleviate the toxicity of acrylamide.

Occurrence in food and associated health risks

Discovery of acrylamide in foods

Hot french fries (chips) are heated to a high temperature

 

Acrylamide was discovered in foods in April 2002 by Eritrean scientist Eden Tareke in Sweden; she found the chemical in starchy foods such as potato chips (potato crisps), French fries (chips), and bread that had been heated higher than 120 °C (248 °F). Production of acrylamide in the heating process was shown to be temperature dependent. It was not found in food that had been boiled, or in foods that were not heated.

Acrylamide has been found in roasted barley tea, called mugicha in Japanese. The barley is roasted so it is dark brown prior to being steeped in hot water. The roasting process produced 200–600 micrograms/kg of acrylamide in mugicha. This is less than the >1000 micrograms/kg found in potato crisps and other fried whole potato snack foods cited in the same study and it is unclear how much of this is ingested after the drink is prepared. Rice cracker and sweet potato levels were lower than in potatoes. Potatoes cooked whole were found to have significantly lower acrylamide levels than the others, suggesting a link between food preparation method and acrylamide levels.

Acrylamide levels appear to rise as food is heated for longer periods of time. Although researchers are still unsure of the precise mechanisms by which acrylamide forms in foods, many believe it is a byproduct of the Maillard reaction. In fried or baked goods, acrylamide may be produced by the reaction between asparagine and reducing sugars (fructose, glucose, etc.) or reactive carbonyls at temperatures above 120 °C (248 °F).

Later studies have found acrylamide in black olives, dried plums, dried pears, coffee, and peanuts.

The US FDA has analyzed a variety of U.S. food products for levels of acrylamide since 2002.

According to the EFSA, the main toxicity risks of acrylamide are "Neurotoxicity, adverse effects on male reproduction, developmental toxicity and carcinogenicity". However, according to their research, there is no concern on non-neoplastic effects. Furthermore, while the relation between consumption of acrylamide and cancer in rats and mice has been shown, it is still not clear whether acrylamide consumption has an effect on the risk of developing cancer in humans, and existing epidemological studies in humans are very limited and don't show any relation between acrylamide and cancer in humans. Food industry workers exposed to twice the average level of acrylamide do not exhibit higher cancer rates.

Acceptable limits

Although acrylamide has known toxic effects on the nervous system and on fertility, a June 2002 report by the Food and Agriculture Organization of the United Nations and the World Health Organization attempting to establish basic toxicology (threshold limit value, no-observed-adverse-effect levels, tolerable daily intake, etc.) concluded the intake level required to observe neuropathy (0.5 mg/kg body weight/day) was 500 times higher than the average dietary intake of acrylamide (1 μg/kg body weight/day). For effects on fertility, the level is 2,000 times higher than the average intake. From this, they concluded acrylamide levels in food were safe in terms of neuropathy, but raised concerns over human carcinogenicity based on known carcinogenicity in laboratory animals.

Opinions of health organizations

The American Cancer Society say that laboratory studies have shown that acrylamide is likely to be a carcinogen, but that as of 2019 evidence from epidemiological studies suggest that dietary acrylamide is unlikely to raise the risk of people developing cancer.

The World Health Organization (WHO) has set up a clearinghouse for information about acrylamide that includes a database of researchers and data providers; references for research published elsewhere; information updates about the current status of research efforts; and updates on information relevant to the health risk of acrylamide in food.

HEATOX (heat-generated food toxicants) study in Europe

The Heat-generated Food Toxicants (HEATOX) Project was a European Commission-funded multidisciplinary research project running from late 2003 to early 2007. Its objectives were to "estimate health risks that may be associated with hazardous compounds in heat-treated food [, and to] find cooking/processing methods that minimize the amounts of these compounds, thereby providing safe, nutritious, and high-quality food-stuffs." It found that "the evidence of acrylamide posing a cancer risk for humans has been strengthened," and that "compared with many regulated food carcinogens, the exposure to acrylamide poses a higher estimated risk to European consumers." HEATOX sought also to provide consumers with advice on how to lower their intake of acrylamide, specifically pointing out that home-cooked food tends to contribute far less to overall acrylamide levels than food that was industrially prepared, and that avoiding overcooking is one of the best ways to minimize exposure at home.

Public awareness

On April 24, 2002, the Swedish National Food Administration announced that acrylamide can be found in baked and fried starchy foods, such as potato chips, breads, and cookies. Concern was raised mainly because of the probable carcinogenic effects of acrylamide. This was followed by a strong, but short-lived, interest from the press. 

On August 26, 2005, California attorney general Bill Lockyer filed a lawsuit against four makers of french fries and potato chips – H.J. Heinz Co., Frito-Lay, Kettle Foods Inc., and Lance Inc. – to reduce the risk to consumers from consuming acrylamide. The lawsuit was settled on August 1, 2008, with the food producers agreeing to cut acrylamide levels to 275 parts per billion in three years, to avoid a Proposition 65 warning label. The companies avoided trial by agreeing to pay a combined $3 million in fines as a settlement with the California attorney general's office.

In 2016, the UK Food Standards Agency launched a campaign called "Go for Gold", warning of the possible cancer risk associated with cooking potatoes and other starchy foods at high temperatures.

In 2018, a judge in California ruled that the coffee industry had not provided sufficient evidence that acrylamide contents in coffee were at safe enough levels to not require a Proposition 65 warning.

Occurrence in cigarettes

Cigarette smoking is a major acrylamide source. It has been shown in one study to cause an increase in blood acrylamide levels three-fold greater than any dietary factor.