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Restoration Ecology in Environmental Science
This document provides an overview of restoration ecology and ecological restoration. It discusses key concepts like ecosystem structure and function, disturbance and succession, resistance and resilience, fragmentation and reference ecosystems. It also describes the need for restoration ecology due to increasing threatened species. As a case study, it outlines mangrove restoration efforts in Andhra Pradesh, India from 1997-2004 that were aimed at regenerating degraded mangrove forests through activities like digging canals to reduce salinity and planting mangrove saplings. Measurement of the project's success included regrowth of indigenous species and self-sustainability of the restored ecosystems.
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Restoration Ecology in Environmental Science
- 1. RESTORATION ECOLOGY INENVIRONMENTAL STUDIES G. KANTHARAJAN AEM-PA6-01 ICAR-CIFE, Mumbai
- 2. How individuals areaffected by/ affects Environment Composition and structure of community Presence/absence, Abundance/rarity among population nothing is ever perfectly balanced - 'relatively stable state' Up and Down but not upwards or downwards trend Biotic: Plants and animals Abiotic: soil, water, air, light, temperature, the climate Balanced (Homeostasis) Cell Tissue Organ Individual Organisms Population Community ECOLOGY
- 3. IF IT CONTINUES… Structureof Ecosystem: a description of the organisms and physical features of environment, amount and distribution of nutrients range of climatic conditions prevailing in the area 2 basic components: 1. Abiotic Components: Inorganic substances – C, N, P etc… Organic substances – Carbohydrate, Protein, Lipid etc… Air, water, substrate and climate regime Radiant energy of sun 2. Biotic Components: • Producers • Macro consumers (Phagotrophs) • Micro consumers (Saprotrophs; decomposers)
- 4. Functions (1) energy ofsun (2) organic materials from inorganic ones by producers (3) Consumption of producers by consumers (4) After the death - complex organic compounds are degraded and finally converted by decomposers The principal steps in the operation of ecosystem not only involve the production, growth and death of living components but also influence the abiotic aspects of habitat. The two ecological processes— energy flow and mineral cycling which involve interaction between biotic and abiotic components lie at the heart of ecosystem dynamics. In this transfer there is a progressive decrease of energy but nutrient component is not diminished and it shows cycling from abiotic to biotic and vice versa.
- 5. Need for RestorationEcology… Threatened species in India (IUCN red list) 2008 – 659 sp 2013 – 973 sp 2014 – 988 sp 64% OF WORLD’S WETLANDS DISAPPEARED SINCE 1900 (RAMSAR, 2015)
- 6. • Restore v.to make almost as good as new; to give back • Research and study of restored populations, communities & ecosystems • the scientific study supporting the practice of ecological restoration “the practice of renewing and restoring degraded, damaged, or destroyed ecosystems and habitats in the environment by active human intervention and action” • emerged as a separate field in ecology in the 1980s • Restoration ecology, as a scientific discipline, is theoretically rooted in conservation biology RESTORATION ECOLOGY
- 7. Concepts Underpinning Goalsof RE Disturbance Many scales and different levels of Severity Natural parts of every ecosystem alter species composition, nutrient cycling & soil properties Natural - weather damage, fire, flooding, treefalls and even volcanic eruptions. Anthropogenic - can alter or destroy natural habitat (like clearing land for agriculture) and/or ecological functions (like damming rivers for flood control).
- 8. FAQ during/after theDisturbance… If uni-directional change acts faster than the organisms' ability to adapt their tolerances; - the system will not be sufficiently resistant - full recovery through succession not possible – Not resilience (1) Will the species of this system be able to tolerate it ? (implying resistance) (2) Is recovery possible through a successional trajectory, back to the same, or at least a desirable, ecosystem state (implying resilience)?
- 9. Resistance Resilience propertyof communities to remain "essentially unchanged" when subject to disturbance Show little impact due to repeated disturbances over time Ability to return to a former successional trajectory after being degraded or deflected by outside disturbances. Immediately impacted by even low intensity disturbances Disturbance without loss Capacity to recover from a disturbance after incurring losses No internal re-organization and successional change is needed System is internally re-organizing, perhaps through a mozaic of patches that are at different stages of re-assembly Loss of resistance can’t display early- warning signals of a collapse Loss of resilience can display early-warning signals of a collapse
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- 11. features of naturalcommunities that contribute to resilience… *ecosystem recovery (the point at which the habitat is functioning normally) from disturbance *resistance to alterations *reversibility of ecosystem changes
- 12. Indicative recovery periodsafter oiling *The goal of a restoration project may be to ‘’initiate or speed the recovery of an ecosystem after disturbance’’ *designed to re-establish natural disturbance regimes
- 13. Ecosystem function the foundationalprocesses of natural systems - nutrient cycles and energy fluxes most basic and essential components of ecosystems An understanding of the full complexity and intricacies of these cycles is necessary to address any ecological processes that may be degraded A functional ecosystem is completely self-perpetuating (i.e. no management required), is the ultimate goal of restorative efforts
- 14. Fragmentation the emergence ofspatial discontinuities in a biological system land use changes and "natural" disturbance Small fragments of habitat small populations vulnerable to extinction decreases interior habitat edge of a fragment has a different range of environmental conditions - different species than the interior
- 15. Contd… reduction in interiorhabitat - extinction of those species which require interior habitat Restorative projects can increase the effective size of a habitat by simply adding area or by planting habitat corridors Reversing the effects of fragmentation and increasing habitat connectivity are central goals of restoration ecology
- 16. Succession ‘’process by whichbiological community composition- the number and proportion of different species in an ecosystem- recover over time following a disturbance event’’ i) Passive restoration - simply allowing natural succession to occur - after removing a source of disturbance - The recovery of the deciduous forests in the eastern United States after the abandonment of agriculture ii) Active restoration involves accelerating the process or attempting to change the trajectory of succession - Mine tailings would take so long to recover passively that active restoration is usually appropriate
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- 18. Options in restoration Rehabilitation: “theaction of restoring a thing to a previous condition or status.” but something that is rehabilitated is not expected to be in as original or healthy a state as if it had been restored. Remediation: act of “to rectify, to make good.” but emphasis is on the process than on the endpoint Reclamation: “the making of land fit for cultivation.” (reclaim = to bring back to a proper state.” but There is no implication of returning to an original state but rather to a useful one Replacement: “to provide or procure a substitute or equivalent in place of” Mitigation: “to appease... So although mitigation can be an outcome of restoration it is a separate consideration
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- 20. Reference ecosystem a. Areference ecosystem can serve as the model for planning an ecological restoration project, and later serve in the evaluation of that project (The Society for Ecological Restoration, 2004). b. a point of advanced development that lies somewhere along the intended trajectory of the restoration. c. consist of one or several specified sites d. A reference is best assembled from multiple reference sites
- 21. How to DefineReference Ecosystems? • ecological descriptions and species lists of similar intact or historical ecosystems • herbarium and museum specimens • historical accounts and oral histories by persons familiar with the project site prior to damage (e.g., expert review) • historical and recent aerial and ground-level photographs
- 22. Dynamic Reference Defining referenceconditions is a challenge in the contemporary landscape • Impacts of human activities • Environmental changes including climate change, species invasion, etc. change of both reference conditions and restored sites are measured simultaneously and are statistically evaluated.
- 23. • rehabilitation andreplacement - offering something different, may provide an endpoint that is more valuable than what was there in the first place • In the heavily developed agricultural land of Britain, sand and gravel workings left to fill with water have contributed enormously to the diversity of wildlife and landscape in many areas. - This is valuable reclamation; however, it is not true restoration although there may be restoration of particular attributes such as biodiversity. Something worthy???
- 24. Ten Hypotheses forRestoration & Rehabilitation Ecology 1. Beyond one or more thresholds of irreversibility, ecosystem degradation is irreversible without structural interventions 2. The more thresholds passed, the more time and energy will be required 3. Without massive intervention, restoration will proceed only as far as the next highest threshold in the process of vegetation change or succession 4. Beta diversity and life form ranges decline with ecosystem degradation, while alpha diversity temporarily increases 5. The loss of keystone species speeds degradation more than the loss of other species
- 25. 6. The reintroductionof keystone species should accelerate rehabilitation - by facilitating the intro. of native species 7. Water and nitrogen use efficiency and nutrient cycling times decrease with ecosystem degradation 8. Diversity of soil biota and their compatibility with extant higher plants decrease with ecosystem retrogression. 9. Between a floor and a ceiling of a given phase of retrogression, resistance increases but resilience decreases. 10. The rate of recovery in restoration 1/∞ structural and functional complexity of the ecosystem
- 26. The Process… • firststep is to restore soils and hydrology to some functional level • conducive to the reintroduction of higher order plants and animals • we can rebuild the conditions of the habitats to closely resemble - initiate a self- sustaining process • Introduce plants and animals • Take care of threat of invasive species • species succession
- 28. Components of restoration •Essentially three matters will need attention: (i) Remodelling the physical aspects of the habitat (ii) Remodelling the chemical aspects, nutrients, and toxicity (iii) replacing missing species or removing undesirable exotics what is required will depend on what is wrong…
- 29. • acid landleft after coal mining will require liming • raw inert materials left to be soils will require nutrients • lakes overcharged with phosphorus may require mud pumping • lost species may require reintroduction • acid land left after coal mining will require liming • raw inert materials left to be soils will require nutrients • lakes overcharged with phosphorus may require mud pumping; • lost species may require reintroduction • acid land left after coal mining will require liming • raw inert materials left to be soils will require nutrients • lakes overcharged with phosphorus may require mud pumping • lost species may require reintroduction • acid land left after coal mining will require liming • raw inert materials left to be soils will require nutrients • lakes overcharged with phosphorus may require mud pumping; • lost species may require reintroduction
- 30. forest ecosystem -500 yr for age structure 5000 yr – for achieving original soil structure biological functions of a soil can be restored in less than 10 yr. Possible to restore the functions fairly completely, but original structure?
- 31. Use of naturalprocesses - harnessed to help restoration – decide - should be used wherever possible, 1. they cost nothing in themselves (although they may cost something to initiate) 2. self sustaining because they originate from within nature (although they may need nurturing in some situations) 3. they can be used on a large scale (achieve full restoration but take a long time and need to be assisted)
- 32. Preservation vs Conservationvs Restoration • Preservation* - an area set aside and protected in its pristine, natural state. • Conservation* – Some resource use is unavoidable; Attempts trying to minimize the unsustainable use of resources • Restoration – Return a degraded resource to its original state * Less Cost effective
- 33. Restoration Ecology vsEcological Restoration the science of restoration A Scientific discipline the practice of restoration. A Societal activity Restoration Ecology vs Conservation Biology Traits CB RE Mind set (Threats of) permanent losses Long-term recovery Dominant organizational levels Genetic, population Community, ecosystem Dominant taxon Vertebrate animals Plants Dominant conceptual theme Population viability and dynamics Succession and assembly Dominant mode of inquiry Decriptive and modeling Experimental
- 34. How to MeasureRestoration Success The society for Ecological Restoration (SER) International had produced the list of nine parameters to measure the restoration success in 2004, 1. Similar diversity & community structure in comparison with reference sites, 2. Presence of indigenous species, 3. Presence of groups which are necessary for long term stability, 4. physical environments capacity to sustain reproducing populations, 5. normal functioning, 6. integration with the landscape, 7. elimination of potential threats, 8. resilience to natural disturbances 9. Self-sustainability
- 35. Some successful restorationprojects in India • the Yamuna Biodiversity Park which is a collaborative effort of Delhi Development Authority and Centre for Environmental Management of Degraded Ecosystems (CEMDE), University of Delhi contains flora and fauna which used to exist 100 years ago and now extinct locally (DDA website). • Mangrove restoration in Andhra Pradesh, India • In Odisha, the Chilka Lake was restored and salinity and biodiversity was revived (UNEP website).
- 36. Case Study :Mangrove Restoration In Andhra Pradesh Original Ecosystem: The total area - 58,263 ha (33,263.32 ha are in Godavari and 24,999.47 ha area in Krishna) Type of Degradation: Extractive Industries, Fisheries & Aquaculture, Infrastructure Disturbances Degradation Description Until 1972, mangroves were clear felled - not been able to regenerate due to topographic changes. Krishna river - heavily utilized - reduction in fresh water flow The rapid siltation and pollution of Kakinada Bay - increased developmental activities and the establishment of fertilizer units - effluents are being discharge - ammonium and nitrate in bay waters – low depth leads to reduced lateral mixing Anthropogenic activities - firewood, fodder, fencing, house construction, thatching and fishing poles. Mangrove forests are also being converted into aquaculture ponds, salt pans and paddy fields with increasing frequency.
- 37. Project Desc: MSSRF,Chennai Funding Source: India-Canada Environment Facility (ICEF) Period : 1997 – 2004 Fund : About 2 billion Stakeholder Involvement: “Microplans” - respective villages for the Mangrove Management Units (MMU) – includes degraded and pristine mangroves for management each Village Level Institution (VLI). The VLIs were trained in nursery raising and digging canals, and the restoration activity was carried out with the cooperation.
- 38. Survey - toidentify the degraded areas Digging of canals to reduce salinity, facilitate tidal flushing, and drain stagnant water A fishbone design - to facilitate easy inflow and outflow of tidal water The main canals were dug at an angle of 45º to the natural creek, and the side canals were dug at an angle of 30 º to the main canal. The canals were dug in a trapezoidal shape - plant the saplings at the mid level of the canal - to ensure that the plants receive tidal water The distance between side canals was 12.5 m during the first year of plantation; however, in subsequent years, this distance was reduced to 8 m in order to ensure a dense canopy. Project Activities PHYSICAL MODIFICATION
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- 40. After a bufferperiod of three months - plantation The planting was done in October and November, after the southwest monsoon, as the influx of rainwater during this period reduces the salinity of the soil – (Utilization of Natural Process) The eight-month-old saplings were planted along the slopes of the canals (20-25 cm from the top) with a gap of 2 m The species Avicennia marina, Avicennia officinalis and Excoecaria agallocha were selected for planting, as these species tolerate a wide range of salinity. Aegiceras corniculatum, Bruguiera gymnorrhiza, Rhizophora apiculata, Rhizophora mucronata and Xylocarpus moluccensis were also planted in order to ensure genetic diversity. BIOLOGICAL MODIFICATION
- 41. A total areaof 520 ha of degraded mangroves was restored in the Godavari and Krishna mangroves. Initially the growth rate of new seedlings was slow, but after 2 to 3 years their growth rate had improved. The bio-diversity of the area has been positively impacted by the restoration - The crab population in the restored areas has increased due to the increased water regime. As biodiversity has improved and the denuded patches have been covered with mangroves, populations of larger animals like otters have also increased substantially. In addition to this, the bird population has shown an increase since the project began. With the improvements made in hydrology, further degradation of mangroves has stopped. Mangroves are now naturally regenerating, and the canopy cover has become denser, as evidenced by remote sensing. An area of 9,442 ha – long term management RECOVERY
- 42. PRO ARGUMENTS 1. Providesa way to reclaim degraded lands to a higher level of ecological functioning, benefiting both humans and wildlife. 2. Ecological restoration sites, especially those in otherwise urban landscapes, are often high-profile installations that may serve to increase public awareness of many environmental issues 3. Ecological restoration provides an alternative to financial penalties
- 43. CON ARGUEMENTS I. Restorationis always next to preservation II. Expensive if done effectively and many times fail to meet expectations III. Ecological restoration, in some cases, is done largely for aesthetic reasons and does little to restore full ecological functioning IV. In many cases, overseers of restoration projects have little information about the original state of a habitat - guesses V. Media miscommunications about successful restoration projects may serve to undermine support for other conservation efforts.
- 44. REFERENCES • Bradshaw, A.D., 1996. Underlying principles of restoration. Can. J. Fish. Aquat. Sci. 53 Suppl (1), 3-9. • Young, Truman P., 2000. Restoration ecology and conservation biology. Biological Conservation (92), 73-83. • Hobbs, R. J. and Harris, J. A., 2001. Restoration Ecology: Repairing the Earth’s Ecosystems in the New Millennium. Restoration Ecology Vol. 9 No. 2, pp. 239–246. • Society for Ecological Restoration International (SER) , Foundations of restoration ecology / edited by Donald A. Falk, Margaret A. Palmer, and Joy B. Zedler ; foreword by Richard J. Hobbs. p. cm. — (Science and practice of ecological restoration) • http://wps.prenhall.com/wps/media/objects/1373/1406592/Regional_Updates/update31.html • Vaughn, K. J., Porensky, L. M., Wilkerson, M. L., Balachowski, J., Peffer, E., Riginos, C. and Young, T. P. (2010) Restoration Ecology. Nature Education Knowledge 3(10):66 • http://www.globalrestorationnetwork.org/database/case-study/?id=60
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Editor's Notes
- #3 Stability and the climax community. When we looked at succession, we saw that some ecologists believed that each ecosystem would, over time, reach a stable state - the climax community. Others argued that natural communities never really stop changing. Given enough time, the latter view must be true - otherwise we might still be hiding from dinosaurs. Stability is probably best regarded as apparent stability - stability for a while. Another term for stability, and a good fashionable one these days, is sustainability. A sustainable ecosystem is one which maintains, over time, features like levels of productivity, processes of nutrient cycling, levels of soil fertility, and its characteristic level of biodiversity. A stable ecosystem, a sustainable ecosystem, is something which keeps working - working in the sense of the processes we have been looking at in the course so far. Stability, in theory at least, can be measured by monitoring these kinds of processes. nothing is ever perfectly balanced - ecosystem in equilibrium is said to be in a 'relatively stable state'. This means that the populations of various animals in the ecosystem are generally staying within a similar range. Populations can go up and down in cycles, as long as there isn't a general upwards or downwards trend
- #4 The structure of an ecosystem is basically a description of the organisms and physical features of environment including the amount and distribution of nutrients in a particular habitat. It also provides information regarding the range of climatic conditions prevailing in the area.
- #9 When considering the potential effect of a certain type of disturbance it is thus useful to ask two questions: (1) Will the species of this system be able to tolerate it (implying resistance), and if not, (2) Is recovery possible through a successional trajectory, back to the same, or at least a desirable, ecosystem state (implying resilience)? It should be clear that the system will not be sufficiently resistant when (even gradual) uni-directional change acts faster than the organisms' ability to adapt their tolerances. If uni-directional gradual change is this fast, the system will not be sufficiently resilient either, as full recovery through succession will then not be possible. Recovery from sudden and local disturbance is usually possible through re-colonization, but the rate of recovery will depend tremendously on the spatial extent of disturbance. For example, recovery from anoxia could take 5 to 8 months at the scale of square meters (Rossi et al. 2009[1]), but could take 5 to 8 years at the scale of a whole bay(Diaz & Rosenberg 1995[2]).
- #15 the emergence of spatial discontinuities in a biological system land use changes and "natural" disturbance, ecosystems are broken up into smaller parts Small fragments of habitat - small populations - vulnerable to extinction decreases interior habitat edge of a fragment has a different range of environmental conditions - different species than the interior reduction in interior habitat and may lead to the extinction of those species which require interior habitat. Restorative projects can increase the effective size of a habitat by simply adding area or by planting habitat corridors that link and fill in the gap between two isolated fragments. Reversing the effects of fragmentation and increasing habitat connectivity are central goals of restoration ecology.
- #21 Reference ecosystem– ideal description of an ecosystem should look like. The description of a reference is complicated by two factors that should be reconciled to assure its quality and usefulness. First, a reference site is normally selected for its well-developed expression of biodiversity, whereas a site in the process of restoration typically exhibits an earlier ecological stage. In such a case, the reference requires interpolation back to a prior developmental phase for purposes of both project planning and evaluation. The need for interpretation diminishes where the developmental stage at the restoration project site is sufficiently advanced for direct comparison with the reference. Second, where the goal of restoration is a natural ecosystem, nearly all available references will have suffered some adverse human-mediated impacts that should not be emulated. Therefore, the reference may require interpretation to remove these sources of artifice. For these reasons, the preparation of the description of the reference requires experience and sophisticated ecological judgement.
- #23 In most cases, the first step is to restore soils and hydrology to some functional level conducive to the reintroduction of higher order plants and animals. Underlying many of these efforts is the belief that if we can rebuild the conditions of the habitats to closely resemble what they were in the past, we can initiate a self-sustaining process whereby most or all of the plants and animals that formerly inhabited the area will once again thrive. In general, such plans involve the direct importation of plants and animals into the habitat. In many cases this is necessary, as there is little hope of these organisms actually colonizing the habitat on their own. At the same time, most restoration projects are plagued by the incessant threat of invasive species, many of which are extremely adept at colonizing disturbed or newly prepared but largely vacant habitats. The removal of weedy invaders such as canary reed grass (in wetlands), Japanese knotweed (in riparian areas), scotch broom, and St. John’s Wort (on prairies) is a primary concern for vigilant land managers engaged in restoration projects. Finally, the idea of species succession, a major theme of community ecology, features prominently in the establishment and monitoring of restoration projects. In Northwest prairies, for instance, fire is instrumental in suppressing some early colonizing species; therefore, resource managers often employ controlled burns to manipulate species composition and abundance. These and many other details stemming from our knowledge about single-species and community ecology (e.g., appropriate levels of genetic diversity and locally adapted genotypes to ensure the survival of introduced plantings) are important to consider in the planning, implementation, and monitoring of restoration projects.
- #24 This is valuable reclamation; however, it is not true restoration although there may be restoration of particular attributes such as biodiversity.
- #25 Beyond one or more thresholds of irreversibility, ecosystem degradation is irreversible without structural interventions combined with revised management techniques. The more thresholds passed, the more time and energy will be required for an ecosystem’s restoration or rehabilitation. Without massive intervention, restoration will proceed only as far as the next highest threshold in the process of vegetation change or succession. Beta diversity and life form ranges decline with ecosystem degradation, while alpha diversity temporarily increases. The loss of keystone species speeds degradation more than the loss of other species.
- #26 The reintroduction of keystone species should accelerate rehabilitation of an ecosystem by facilitating the reintroduction and establishment of additional native species. Water and nitrogen use efficiency and nutrient cycling times decrease with ecosystem degradation. Diversity of soil biota and their compatibility with extant higher plants decrease with ecosystem retrogression. Between a floor and a ceiling of a given phase of retrogression, resistance increases but resilience decreases. The rate of recovery in restoration or rehabilitation pathways is inversely related to the structural and functional complexity of the ecosystem of reference.
- #43 PRO AND CON ARGUMENTS Pro Arguments 1. Restoration ecology provides a way to reclaim degraded lands to a higher level of ecological functioning, benefiting both humans (by providing “nature’s services”) and wildlife. 2. Ecological restoration sites, especially those in otherwise urban landscapes, are often high-profile installations that may serve to increase public awareness of many environmental issues, including the merits of inherently valuing natural resources as well as reversing common trends in urban/suburban sprawl and unplanned development. 3. Ecological restoration provides an alternative to financial penalties through which private and public organizations that are responsible for environmental degradation may contribute to future environmental stewardship in a meaningful way. Con Arguments 1. Restoration efforts, if done effectively, are often prohibitively expensive and many times fail to meet expectations in many cases, portions or entire communities fail to establish and thrive despite the best efforts of restorationists. 2. Ecological restoration, in some cases, is done largely for aesthetic reasons and does little to restore full ecological functioning to habitats in any real meaningful way. In many cases, overseers of restoration projects have little information about the original state of a habitat, thereby reducing management decisions to best guesses about what sort of conditions would be most appropriate. 3. Media miscommunications about successful restoration projects may serve to undermine support for other conservation efforts. Parties opposed to conservation efforts may argue that, as we become more knowledgeable about the science of restoration, any habitat may be restored to its former state, and hence it needn’t be of special concern. On a larger scale, the public may be less concerned about conservation if too much faith in the ability of scientists to prescribe a “magic bullet” for restoring full ecological functioning to any habitat becomes part of the public consciousness.
- #44 Restoration is always next to preservation Restoration efforts, if done effectively, are often prohibitively expensive and many times fail to meet expectations in many cases Ecological restoration, in some cases, is done largely for aesthetic reasons and does little to restore full ecological functioning to habitats In many cases, overseers of restoration projects have little information about the original state of a habitat, thereby reducing management decisions to best guesses about what sort of conditions would be most appropriate. Media miscommunications about successful restoration projects may serve to undermine support for other conservation efforts. Parties opposed to conservation efforts may argue that, as we become more knowledgeable about the science of restoration, any habitat may be restored to its former state, and hence it needn’t be of special concern.