What motivates ecological restoration?

Ecological restoration projects are motivated by diverse environmental and social reasons. Motivations likely vary between stakeholders or regions, and influence the approach taken to plan, implement, and monitor restoration projects. We surveyed 307 people involved in the restoration of native vegetation across Australia to identify their underlying motivations. We also elicited information on planning, implementation, and monitoring of restoration projects. We found that biodiversity enhancement is the main motivation for undertaking restoration, with biodiversity offsetting, water quality improvements, and social reasons as important secondary motivations. Motivations varied significantly by stakeholder type and region. Restoration projects primarily motivated by ecosystem service provision (e.g. water quality improvements and social reasons) sought less pristine ecological outcomes than projects motivated by biodiversity enhancement or offsetting. Rigorous monitoring designs (e.g. quantitative, repeatable surveys, and use of performance indicators) were rarely used in restoration projects, except for projects motivated by scientific research. Better alignment of different restoration motivations with the planning and monitoring of restoration projects should deliver greater benefits through setting appropriate objectives and evaluating outcomes against these objectives. These improvements will increase the capacity of the restoration practice to meet international biodiversity commitments and communicate restoration outcomes to stakeholders.     

Spicing up restoration: can chili peppers improve restoration seeding by reducing seed predation?

Seed predation by rodents presents a significant barrier to native plant recruitment and can impede restoration seeding efforts. In nature, some plants contain secondary defense compounds that deter seed predators. If these natural defense compounds can be applied to unprotected seeds to inhibit rodent granivores, this approach could improve restoration seeding. Capsaicin is the active ingredient in chili pepper (Capsicum spp.) seeds that creates the burning sensation associated with human consumption of hot peppers. This compound has a similar effect on other mammals and is believed to have evolved as a deterrent to rodent seed predators. We used seed‐coating techniques to attach powder ground from Bhut Jolokia (Capsicum chinense) peppers to native plant seeds and evaluated the efficacy of these seed coatings for deterring rodent seed predation and enhancing native plant recruitment using laboratory and field experiments. Laboratory feeding trials demonstrated that native deer mice (Peromyscus maniculatus) consumed far fewer pepper‐coated seeds compared to untreated control seeds. Field seed‐addition experiments consistently demonstrated that rodent seed predation reduced native plant recruitment over the 4‐year study. Coating techniques used in the first 3 years were not persistent enough to reduce rodent seed predation effects on plant recruitment. However, a more persistent coating applied in conjunction with late‐winter sowing negated rodent seed predation effects on recruitment in year 4. Our results demonstrate that coating seeds with natural plant defense compounds may provide an effective, economical way to improve the efficacy of plant restoration by deterring seed predation by ubiquitous rodent granivores.     

When is restoration not?: Incorporating landscape-scale processes to restore self-sustaining ecosystems in coastal wetland restoration

With increasing restoration initiatives for coastal wetlands, the question of ‘What are we restoring to?’ becomes more pressing. The goal of this paper is to explore restoration concepts, examples, and challenges from the Pacific and Gulf coasts. One of the fundamental concepts explored is change over time – either in the controlling processes or the restoration structure – and how such changes can be meshed with the goals of various restoration efforts. We subsequently review the concepts of ecosystem trajectories, alternative restoration approaches, and the ideal attributes of functional self-sustaining restoration in the context of realities of restoration planning, design, and implementation. These realities include the dynamics of the ecosystems being restored, very real constraints that are imposed by the contemporary physical and human landscape, and the need to plan for the long term development of restoration sites recognizing that both project performance and expectations may change over time.     

River restoration concepts — goals and perspectives

An analysis of restoration projects carried out both in Austria and abroad shows that most projects are limited to design measures within the river bed with the general intention to increase habitat diversity. The various measures are not based on the type-specific characteristics of the river and thus there is a danger of creating uniform restoration stretches, independent of the specific landscape area, river morphology, discharge regime or site specific biocoenoses. Such proceeding lacks in considering a comprehensive improvement of ecological functioning of the whole river-system. To meet those demands a type-specific guiding view (Leitbild) has to be developed based on the pristine river conditions.The comparison of the river pattern including the characteristic features of its unmodified state with the actual situation leads to a comprehensive set of measures. The essential goals of such management-concepts are the integrity of the river habitat, self-regulation and self-regeneration, the preservation of intact resources, as well as the possibility to experience the uniqueness, diversity and beauty of natural river landscapes.     

Can carbon credits fund riparian forest restoration?

Ecological restoration is increasingly called on to provide ecosystem services (ES) valuable to humans, as well as to benefit biodiversity and improve wildlife habitat. Where mechanisms to pay for ES exist, they may serve as incentives to embark on habitat restoration projects. We evaluated the potential of newly established carbon markets in the United States to incentivize afforestation along riparian corridors, by comparing the income earnable by carbon offset credits with the costs of planting, maintaining, and registering such a restoration project in California. We used a 20‐year chronosequence of riparian forest sites along the Sacramento River as our model project. We found that carbon credits can repay more than 100% of costs after two decades of regrowth, if sufficient effort is put into sampling intensity in the first post‐restoration decade. However, carbon credits alone are unlikely to entice landowners currently engaged in agricultural activities to switch from farming crops to farming habitat.     

Can exotic pine trees assist in restoration?

Invasive exotic woody species, including conifers escaped from plantations, are usually regarded as serious threats to native biodiversity. Becerra & Montenegro (Applied Vegetation Science, 16, 2013, 2) present an interesting example of invasive Pinus radiata facilitating native woody regeneration in semi‐arid central Chile. However, the positive value of invasive conifers for restoration and conservation will not necessarily apply in all situations.     

Dispersal-limited species – A challenge for ecological restoration

In recent years, increasing efforts have been directed to the restoration of natural communities affected by human activities. However, restoration success is often reduced because of the lack of dispersal-limited species in the restored site. Numerous rare species are dispersal-limited, having low probabilities to re-colonize restored sites and to establish viable populations. A high species richness enhances the ability of ecosystems to maintain multiple functions. It has been shown that in highly diverse ecosystems such as alpine meadows, tropical forests and coral reefs, the most distinct combinations of functions are supported predominantly by rare species. Thus, more emphasis should be given to support rare species in restoration actions. I suggest that well-known techniques for increasing plant diversity in restoration projects should be complemented with techniques to re-introduce dispersal-limited animals. Re-establishing ecological connectivity might be of benefit for certain species in the long term. However, for the majority of dispersal-limited animal species, translocations of founder individuals might be the only tool to re-establish populations in restored sites.     

Testing heterogeneity–diversity relationships in tropical forest restoration

Restoring small-scale habitat heterogeneity in highly diverse systems, like tropical forests, is a conservation challenge and offers an excellent opportunity to test factors affecting community assembly. We investigated whether (1) the applied nucleation restoration strategy (planting tree islands) resulted in higher habitat heterogeneity than more homogeneous forest restoration approaches, (2) increased heterogeneity resulted in more diverse tree recruitment, and (3) the mean or coefficient of variation of habitat variables best explained tree recruitment. We measured soil nutrients, overstory and understory vegetation structure, and tree recruitment at six sites with three 5- to 7-year-old restoration treatments: control (no planting), planted tree islands, and conventional, mixed-species tree plantations. Canopy openness and soil base saturation were more variable in island treatments than in controls and plantations, whereas most soil nutrients had similar coefficients of variation across treatments, and bare ground was more variable in control plots. Seedling and sapling species density were equivalent in plantations and islands, and were substantially higher than in controls. Species spatial turnover, diversity, and richness were similar in island and plantation treatments. Mean canopy openness, rather than heterogeneity, explained the largest proportion of variance in species density. Our results show that, whereas canopy openness and soil base saturation are more heterogeneous with the applied nucleation restoration strategy, this pattern does not translate into greater tree diversity. The lack of a heterogeneity–diversity relationship is likely due to the fact that recruits respond more strongly to mean resource gradients than variability at this early stage in succession, and that seed dispersal limitation likely reduces the available species pool. Results show that planting tree islands facilitates tree recruitment to a similar degree as intensive plantation-style restoration strategies.     

Ecosystem restoration with teeth: what role for predators?

Recent advances highlight the potential for predators to restore ecosystems and confer resilience against globally threatening processes, including climate change and biological invasions. However, releasing the ecological benefits of predators entails significant challenges. Here, we discuss the economic, environmental and social considerations affecting predator-driven ecological restoration programmes, and suggest approaches for reducing the undesirable impacts of predators. Because the roles of predators are context dependent, we argue for increased emphasis on predator functionality in ecosystems and less on the identities and origins of species and genotypes. We emphasise that insufficient attention is currently given to the importance of variation in the social structures and behaviours of predators in influencing the dynamics of trophic interactions. Lastly, we outline experiments specifically designed to clarify the ecological roles of predators and their potential utility in ecosystem restoration.     

Climate change and plant invasions: restoration opportunities ahead?

Rather than simply enhancing invasion risk, climate change may also reduce invasive plant competitiveness if conditions become climatically unsuitable. Using bioclimatic envelope modeling, we show that climate change could result in both range expansion and contraction for five widespread and dominant invasive plants in the western United States. Yellow starthistle ( Centaurea solstitialis ) and tamarisk ( Tamarix spp.) are likely to expand with climate change. Cheatgrass ( Bromus tectorum ) and spotted knapweed ( Centaurea biebersteinii ) are likely to shift in range, leading to both expansion and contraction. Leafy spurge ( Euphorbia esula ) is likely to contract. The retreat of once-intractable invasive species could create restoration opportunities across millions of hectares. Identifying and establishing native or novel species in places where invasive species contract will pose a considerable challenge for ecologists and land managers. This challenge must be addressed before other undesirable species invade and eliminate restoration opportunities.     

Conservation and restoration of plant–animal mutualisms on oceanic islands

Islands harbour much of the world's threatened biodiversity. Recent work has highlighted how it is not species diversity per se but rather the interactions between organisms that breathes life into ecosystems. Thus, the real challenge to preserving and restoring biodiversity on islands is not to only focus on species themselves, but more importantly on maintaining and restoring the integrity of interactions between the species. Here we argue that mutualistic plant–animal interactions play a pivotal role with regards to conservation and restoration on islands. Furthermore, these interactions are ideally suited for inter-island comparisons due to ecological and evolutionary similarities across geographical and taxonomical boundaries. The similarities include highly generalised mutualistic systems, the evolution and readjustment of plant reproductive traits, and a disharmony in taxonomic groups of mutualists, compared to continental ecosystems. We highlight past and present threats to island plant–animal mutualisms, as well as the challenges and opportunities inherent to these interactions. In particular, we (1) argue that mutualistic networks provide an ideal approach to collect information and advance our knowledge on the systems, (2) suggest the use of interactions as biodiversity monitoring and assessment tools, (3) highlight the differences and similarities between pollination and seed dispersal interactions in the context of restoration, and (4) briefly discuss the ambiguous role of alien invasive species in the management of mutualistic interactions. Finally, we highlight how a recently proposed but controversial restoration strategy, rewilding, can be gainfully applied to and further advanced in island settings.     

Spontaneous revegetation of mined peatlands: An useful restoration tool?

The recent development of peatlandrestoration activities indicates thatmodern peat mining techniques seriouslyhamper the natural capacity of bogecosystems to regenerate after adisturbance. However, some plants have theability to colonize dry peat deposits, andseem to help stabilize the soil surface andfacilitate the establishment of other plantspecies. In this paper, we review studiesregarding the spontaneous regeneration ofombrotrophic peatlands. There are numerousexamples throughout North America andEurope showing that spontaneousrevegetation of mined peatlands by typicalbog plants, and particularly by Sphagnum species, is possible. However,this phenomenon is much more common inblock-cut peatlands than in vacuum-minedsites. The slow recovery of vacuum-minedpeatlands compared to block-cut sites isprobably related to intense drainagenecessary for the use of tractor-drawnvacuum machines. There are some cases,however, where the spontaneous revegetationof vacuum-mined sites is successful,particularly for vascular plants. Thesesites are mainly dominated by cotton-grass(Eriophorum vaginatum L.). Itseems that the microclimatic conditionscreated by cotton-grass tussocks improveestablishment conditions for other vascularand non-vascular plants. Restorationactivities should be minimal in minedpeatlands already invaded by cotton-grass,and spontaneous revegetation processescould and should be integrated intopeatland restoration programs.     

Does restoration work? It depends on how we measure success

The restoration of 4 partial stream barriers was evaluated in watersheds of Terra Nova National Park, Newfoundland, Canada from 2009 to 2011. Brook trout (n = 462) were tagged and tracked moving through our study sites using passive‐integrated transponder telemetry and the restoration actions were assessed using 3 different measures: passage success rates; the range of passable flows; and the availability of passable flows. We considered the observed results within a before‐after‐control‐impact (BACI) design that included reference reaches and pre‐restoration observations. The conclusions of BACI analyses were also contrasted with those that would have been obtained from commonly used before‐after (B‐A) or control‐impact (C‐I) study designs. While the restoration actions changed hydrological conditions in a way that should facilitate fish passage, our biological measures indicated that success was variable across culverts and within culverts depending on the measure evaluated. Furthermore, the natural temporal and spatial variability of fish movements often resulted in different conclusions between the more robust BACI design and the more commonly used B‐A and C‐I designs. Our results demonstrate that restoration of partial barriers may not always yield dramatic improvements. Furthermore, without suitable controls, the chances of drawing false conclusions regarding restorations in temporally and spatially dynamic systems are substantial.     

To what extent can and should revegetation serve as restoration?

Desertification and climate change are degrading large areas of arid and semiarid habitat in many regions. In response, many countries have implemented revegetation programs, commonly using Atriplex nummularia, native to Australia. Although not intrinsically targeted at habitat restoration, these programs aim to restore (stabilize) erosional processes and provide livestock forage (usually goats, sheep). Few investigators have assessed the utility of these novel habitats for native fauna. In a recent, extensive survey of small mammal communities in lands revegetated with A. nummularia in north‐central Chile, we captured a single animal, the marsupial (Thylamys elegans). We also captured no birds in our live traps and saw numerous darkling beetles in traps. These striking results contrasted with data from a nearby ungrazed park with natural vegetation where 10 small mammal species are known with total abundances ranging from 15 to 80 animals in similar sampling efforts. These revegetated lands provide poor habitat for native mammals, and we argue that revegetation efforts should include proactive risk assessment and cost‐benefit analyses in a structured decision‐making framework. In addition, managers should target increased plant species diversity to support broader biological diversity in addition to the need to control erosion. Although our work has focused on revegetation with Atriplex, numerous other plant species have been intentionally introduced to arid lands, usually for economic reasons; many of these, like Atriplex, have unintended consequences for native biota.     

Can pollination syndromes indicate ecological restoration success in tropical forests?

We evaluated the pollination syndromes of plant species occurring in revegetated patches of riparian Atlantic Forest in order to evaluate the success of restoration process. Between March 2013 and January 2014, the floral traits of all of the flowering plants found in, among four restoration sites of different ages and one reference site, were recorded and used to characterize pollination syndromes. Richness, abundance, and composition of pollination syndromes were related to season, age and width of the forest fragment, species richness and abundance of sampled plants, and also to the quality of the surrounding matrix. There were differences in the composition of syndromes among sampling units and among seasons. Richness and abundance of pollination syndromes varied among climatic periods, the highest values occurred at the end of the dry season and the start of the rainy season. Older, wider, and areas with more plants had higher values of richness and abundance of syndromes. The quality of the surrounding matrix influences only the richness of syndromes. It was concluded that floral traits are good indicators of ecological restoration of riparian forests and that the surrounding matrix contributes to the greater richness of syndromes. However, when planning for active restoration, attention should be given to the proper choice of plant species on the basis of pollination syndromes that should attract pollinators.     

Dynamic restoration in Möbius and Möbius-like patients

M?bius syndrome is classically characterized by bilateral facial nerve and abducens nerve paralysis in combination with limb defects. In the past 110 years, physicians diagnosed children as having the syndrome on the basis of heterogeneity of symptoms and used the term "M?bius syndrome" or "M?bius-like syndrome" for patients with multiple cranial nerve involvement. The cause and the exact pathogenesis of the syndrome still elude understanding. Genetic work-ups, radiological findings, and data from autopsies differ in their approaches and their findings of the basic causes of M?bius syndrome. In the international literature, about 301 case reports are found scattered through the past century. The appearance of the facial deformity is easy to recognize, because the M?bius patient is impaired in his or her ability to communicate nonverbally. Despite ophthalmologic problems, it is the search for a smile that brings these patients to the reconstructive surgeon. Over the past 100 years, surgical efforts attempted to improve the mask-like appearance by static and dynamic procedures, usually local muscle transpositions. Today, combinations of microsurgical procedures and aesthetic techniques are being used to restore some movement to the expressionless face of these patients by nerve and muscle transplantation. This article discusses the heterogeneity of M?bius syndrome, advocates a new classification system, presents the clinical findings of 42 patients who were seen and examined in consultation, and discusses the surgical management of 20 patients who underwent dynamic restorative microsurgery. Exemplary cases illustrating the preoperative work-up regimen and possible outcomes are reported.     

Degraded or just different? Perceptions and value judgements in restoration decisions

An underlying premise of ecological restoration is that it focuses on the recovery of degraded systems. While this is an apparently straightforward aim, there is in fact considerable variation in how the term “degraded” is defined, used and assessed. In addition, there is a notable subjective component to decisions regarding what is degraded and what isn't, and this often relates to the values and goals being considered. There is likely to be little argument over highly degraded systems where damage and loss of valued characteristics are evident. But where system change is less stark and the changes have mixed benefits and disbenefits, the decision on whether the system is degraded and hence in need of restoration becomes more difficult. As systems continue to change in the face of ongoing climate, land use and other environmental changes, decisions become more difficult regarding which systems are degraded and which are merely different from what was there before. Difference does not necessarily equate to degradation. Effective use of scarce management resources relies on an improved ability to openly debate and resolve such issues.     

What is the value of wild animal welfare for restoration ecology?

The restoration community continues to discuss what constitutes good environmental stewardship. One area of tension is the extent to which the well‐being of wild animals should inform restoration efforts. We discuss three ways that the perspective of wild animal welfare can augment restoration ecology: strengthening people's relationship with nature, reinforcing biotic integrity, and reducing mechanistic uncertainty. The animal welfare movement elevates sentient animals as stakeholders and explores how environmental context directly impacts the well‐being of individuals. Viewing wild animals through this lens may encourage people to think and act with empathy and altruism. Second, we incorporate animal welfare into the concept of biotic integrity for ecological and ethical reasons. Restoring ecosystem processes may enhance animal welfare, and vice versa. Alternatively, there may be a trade‐off between these factors, requiring local decision‐makers to prioritize between restoring ecosystem function and promoting individuals' well‐being. We conclude by discussing how welfare can impact population recovery, thereby adding insights about mechanisms underpinning restoration objectives. Ultimately, restoration ecologists and proponents of wild animal welfare could enjoy a productive union.     

The hemiparasite Pedicularis palustris: ‘Ecosystem engineer’ for fen-meadow restoration

‘Ecosystem engineers’ have a critical role in the structure and function of natural communities and need to be considered as focal species to enable successful conservation or restoration of ecosystems. Through introduction and/or managing a single species, an entire community can be influenced. In our study we show that Pedicularis palustris, an endangered hemiparasite in large parts of Europe, can act as an ‘ecosystem engineer,’ speeding up the restoration of undrained fen-meadow ecosystems colonised by species-poor and resistant Carex acuta vegetation. The parasitic behavior of Pedicularis palustris on tall sedges significantly alters local plant diversity, biomass production and soil characteristics. Our experiments show that, under the right hydrological conditions and mowing management practice, several target species for nature conservation can benefit from the gaps it creates in above-ground Carex acuta vegetation and its dense below-ground root system. The more prominent presence of mosses and lower density of the topsoil stimulates the recovery of mesotrophic transition mire with active peat formation. Since this habitat type is specifically protected under the European Habitat Directive, (re)introduction of Pedicularis palustris in similar sites within its geographical distribution range in Europe may be a helpful tool to achieve the imposed obligations for appropriate management and restoration.