Assessing Restoration Success Research Articles

Modelling Water Depth, Turbidity and Chlorophyll Using Airborne Hyperspectral Remote Sensing in a Restored Pond Complex of Doñana National Park (Spain)

Restored wetlands should be closely monitored to fully evaluate the effectiveness of restoration efforts. However, regular post-restoration monitoring can be time-consuming and expensive, and is often absent or inadequate. Satellite and airborne remote sensing systems have proven to be cost-effective tools in many fields, but they have not been widely used to monitor ecological restoration. This study assessed the potential of airborne hyperspectral remote sensing to monitor water mass characteristics of experimental temporary ponds in the Mediterranean region. These ponds were created during marsh restoration in Doñana National Park (south-west Spain). We used hyperspectral images acquired by the CASI-1500 hyperspectral airborne sensor to estimate and map water depth, turbidity and chlorophyll a in a subset of the 96 new ponds. The high spatial and spectral resolution of the CASI sensor allowed us to detect differences between ponds in water depth, turbidity and chlorophyll a, providing accurate mapping of these three variables, and a useful method to assess restoration success. High levels of spatial variation were recorded between different ponds, which likely generates high diversity in the animal and plant species that they contain. These results highlight the great potential of hyperspectral sensors for the long-term monitoring of wetland complexes in the Mediterranean region and elsewhere.

Trait-based approach of aquatic insects to track recovery of wetland ecosystems in Northeast China

Wetland restoration has received increasing attention to compensate for the continuing loss of natural wetlands and revive biodiversity and associated ecological functions. The development of methods for assessing the effectiveness of restoration measures is important for wetland management. However, most studies assessing restoration success in freshwater ecosystems are based on taxonomic biodiversity; trait-based approaches remain limited, particularly in wetland ecosystems. Here, we assess the effectiveness of wetland restoration in the Sanjiang Plain, Northeast China, based on the trait composition and functional diversity of aquatic insect assemblages. We found that functional richness in restored wetlands was significantly higher than impacted wetlands but lower than natural wetlands. Compared to natural wetlands, functional beta diversity of impacted wetlands was higher. In terms of dissimilarity between wetland types, trait composition of aquatic insects in restored wetlands showed a higher similarity to natural wetlands compared to those in impacted wetlands. Trait compositions of aquatic insect assemblages in restored wetlands were more similar to impacted wetlands in May but showed a greater similarity to natural wetlands in October. Our study shows that restoration measures have facilitated the partial recovery of functional diversity and trait composition of aquatic insect assemblages in the Sanjiang Plain wetlands. Our study confirms the potential of using trait-based approach to assess the effectiveness of wetland restoration. Given that assessments based on taxonomic and trait data can provide complementary information, we recommend incorporating both taxonomic and functional metrics and considering seasonal dynamics of wetlands in post-restoration monitoring and assessment in wetlands.

Determining mussel restoration success: An Australasian case study

Restoration is becoming an increasingly common management tool to aid in recovering degraded, damaged, or destroyed ecosystems. Developing and adopting best practices are valuable for maximising restoration efficiency. This frequently includes using natural reference sites to guide restoration goals and target setting, as well as assessing restoration success. Natural reference sites are representative of an ecosystem that has not experienced intense degradation and provides a basis for the conditions that restoration is aspiring to achieve. However, in the instance of mussel reefs, historical overharvesting and habitat degradation have led to a widespread decline in natural reefs, with few natural sites remaining. While mussel restoration is receiving increased efforts, the absence of reference conditions has resulted in many projects lacking clearly defined and achievable restoration goals. This study aims to improve the efficiency of mussel restoration by developing example restoration goals and a theoretical reference system. A broad range of restoration goals are proposed in line with associated ecosystem services, which restoration practitioners can adapt and apply depending on specific project objectives. A dynamic theoretical reference system for mussel restoration is also developed using knowledge of past reefs, observations from remaining reefs, and anticipated future conditions. Two case studies of the application of restoration goals and the theoretical reference system are provided for mussel restoration projects within New Zealand and Australia. This research provides guidance for restoration practitioners to effectively plan and assess progress of restoration, in line with project goals and targets.

The role of dominant prairie species ecotypes on plant diversity patterns of restored grasslands across a rainfall gradient in the US Great Plains

AbstractQuestionsA robust ecosystem requires a functionally heterogeneous community of organisms with ecological traits that permit broad resource partitioning. Understanding community diversity patterns can help investigate drivers of community assembly and assess restoration success. Do biodiversity patterns differ among grassland communities sown with different ecotypes of dominant species during restoration along a rainfall gradient in the tallgrass prairie of the central US Great Plains?LocationFour field sites across a rainfall gradient within the North American Great Plains: Colby, Kansas (39°23′17.8″N, 101°04′57.4″W), Hays, Kansas (38°51′13.2″N, 99°19′08.6″W), Manhattan, Kansas (39°08′22.3″N, 96°38′23.3″W), and Carbondale, Illinois (IL, 37°41′47.0″N, 89°14′19.2″W).MethodsWe applied linear mixed models to assess the effect of dominant species ecotype, year, and location on grassland taxonomic, phylogenetic, and functional diversity.ResultsThe non‐local grass ecotype (compared to the local ecotype) promoted species richness. In contrast, the effect of the dominant species ecotype on phylogenetic or functional diversity was site‐specific over the 10‐year restoration. Richness decreased across the rainfall gradient from dry to moist sites, and the wettest site had the highest phylogenetic and functional diversity.ConclusionsOur results suggest that abiotic filtering by rainfall is a key assembly mechanism that could predict grassland changes in biodiversity in the early restoration phases. Given the community response across the tallgrass prairie, restoration practitioners should consider the impact of regional sources of dominant species used in restoration when biodiversity is a restoration goal. It is recommended for future grassland restoration to detect gaps and limitations in evolutionary and trait structure that will reveal which diversity components to evaluate.

Research Opportunity on Fractional Cover of Forest: A Bibliometric Review

Forests are threatened globally by deforestation. Forest restoration at the landscape scale can reduce these threats. Ground-based and remote sensing inventories are needed to assess restoration success. Fractional canopy cover estimated from forest algorithms can be used to monitor forest loss, growth, and health via remote sensing. Various studies on the fractional cover of forest have been published. However, none has yet conducted a bibliometric analysis. Bibliometrics provide a detailed examination of a topic, pointing academics to new research possibilities. To the best of the authors’ knowledge, this is the first bibliometric study screening publications to assess the incidence of studies of the fractional cover of forests in Web of Science (WoS) and Scopus databases. This research analyses WoS and Scopus publications on the fractional cover of forest dating from 1984 to 2021. The current study uses the Bibliometrix R-package for citation metrics and analysis. The first paper on the fractional cover of forest was published in 1984 and annual publication numbers have risen since 2002. USA and China were the most active countries in the study of fractional cover of forests. A total of 955 documents from 69 countries with multiple languages were retrieved. Vegetation, forestry, and remote sensing were the most discussed topics. Findings suggest more studies on the fractional cover of forests algorithms should be conducted in tropical forest from developing countries.

Modelling restoration of natural flow regimes in dam impaired systems: Biomorphodynamic effects and recovery times

Dams affect the natural flow regime by altering the magnitude, timing and frequency of high and low flows. Many river ecosystems impaired by dams are currently being restored. Restoration success is difficult to quantify and is often assessed by comparing the restored system to an unimpaired static ‘reference’ system. However, restoring a river to past environmental conditions and assessing restoration success by comparing it to a static situation neglects natural system dynamics and non-linear, adaptive system responses. With this modelling study we evaluate long-term changes in river morphology, morphodynamics, riparian vegetation cover and habitat suitability of two fish species and two types of wetland vegetation in a meandering gravel bed river after removal of an upstream dam and complete restoration of the natural flow regime. We assessed the ecological and hydromorphodynamic recovery of systems impaired by two different dam operating regimes and three different time periods the dam was present by comparing these to a dynamic undisturbed situation. Modelling results show that recovery potential depends on how much the system has been changed by the dam and the system state at the start of the restoration, rather than the duration of the pressure. Even if the conditions shortly after restoration are comparable to pre-disturbance conditions, there can still be a time-lag in the system response where the future state of the restored system continues to deviate from the undisturbed situation. When this happens, the system can develop into an alternative dynamic equilibrium where recovery becomes increasingly difficult. These results stress the importance of considering natural variability in restored systems as well as in reference systems, requiring detailed spatio-temporal monitoring to assess restoration effects.

Restored saltmarshes have low beta diversity due to limited topographic variation, but this can be countered by management

Abstract Spatial heterogeneity of species (beta diversity) is an important attribute of ecological communities, but is less frequently considered when assessing restoration success than other aspects of diversity (gamma and alpha). Differences in beta diversity between restored and natural sites may arise due to differences in environmental heterogeneity. We used a nested sampling design to survey plant communities and environmental conditions (elevation, redox potential and metrics of topography) on four pairs of restored and natural saltmarshes. We assessed whether there were differences in both alpha and beta diversity between natural and restored sites and analysed their environmental drivers. Topography was an important driver of plant alpha diversity and beta diversity on saltmarshes. The effects of topography were partly indirect, mediated though changes in redox potential, but topography also influenced plant communities independently of both elevation and redox. Restored saltmarshes were less heterogeneous in topography than natural marshes. This reduced topography was reflected in lower beta diversity; plant communities 1 m apart in natural marshes were as dissimilar as those found 20 m apart in restored marshes. Large‐scale topographic manipulation carried out at one site a decade after initial restoration successfully increased topographic heterogeneity and increased beta diversity when surveyed 3 years after manipulation. These changes were still evident when resurveyed after a further 2 years. Synthesis and applications. Increasing environmental heterogeneity can improve restoration outcomes by increasing beta diversity on restored sites. The effect of environmental heterogeneity is likely to be particularly strong within intertidal habitats such as saltmarshes, where small changes in topography can determine whether a species can occur at a given location. Topographic manipulation is a feasible post‐restoration technique that can be applied to ensure restored saltmarshes better meet policy targets of biological, physical and functional equivalence with natural marshes.

Leveraging time series of satellite and aerial images to promote the long‐term monitoring of restored plant communities

AbstractAimsEcological restoration is integral to meeting conservation goals in rapidly changing landscapes, but outcomes vary substantially with some projects failing to meet their targets. To understand the causes of this variability, long‐term monitoring of existing projects is critical, but this comes at considerable costs. Current literature counts several studies using time series of satellite images to assess vegetation responses to disturbances and landscape transformations. Yet such methods are seldom used in the restoration literature and in practice. This synthesis seeks to identify how common remote sensing approaches for the assessment of plant recovery could inform the monitoring and management of restored plant communities.MethodsThis paper reviews the methods and metrics used to detect trajectories (i.e., change through time) in plant properties from rich time series of aerial and satellite images following change drivers including fire, extreme climatic events, climate change, and pest outbreaks. Specifically, it reviews the sensors, vegetation properties, modeling approaches, and indicators that can help measure plant stress and response to interventions.Results and ConclusionsRemote sensing methods commonly used in disturbance ecology and assessments of land‐cover changes could inform the monitoring of restoration projects at low cost and over large spatio‐temporal scales, thus bridging the gap between field surveys to rapidly identify stressors or unexpected vegetation responses. Potential applications include comparing sites to identify factors impacting their responses to restoration, assessing restoration success, and testing ecological hypotheses to guide future project planning and design.

Environmental Cues of Spawning Migration into a Confined Wetland by Northern Pike and Common Carp in Lake Erie: Identifying Fine‐Scale Patterns

AbstractRestoration of wetlands in the Laurentian Great Lakes is designed to improve numerous ecosystem services including nutrient sequestration, support recreational uses, augment waterfowl habitat, and provide spawning and nursery habitat for fish. These projects often use Northern Pike Esox lucius, as a sentinel species for assessing restoration success because of their obligate use of emergent and submergent vegetation by the early life stages. However, invasive species such as Common Carp Cyprinus carpio also utilize these habitats and can have negative effects. Thus, fostering the use of these wetlands by Northern Pike and limiting access by invasive carp is a common restoration management concern. Using a dual frequency sonar system to observe fish migration in a recently connected Lake Erie coastal wetland, we were able to identify fine‐scale environmental correlates to immigration by each species during early spring. Both species overwhelmingly migrated during daylight hours and against the flow of water that was generated through seiche‐driven water oscillations. However, Northern Pike predominantly immigrated during the initial increase in water temperature immediately after ice‐out; Common Carp also began to enter the wetland at low temperatures shortly after ice‐out, but immigration exhibited a slow exponentially increasing pattern, such that the primary immigration timing differed by almost 30 d. Thus, we demonstrate common fine‐scale spawning migration patterns (i.e., water oscillation effects and time of day) for both species and reinforce the temperature‐correlated differences in spawning migration. Using these results could enable managers of connected wetlands to more precisely and dynamically manage habitat accessibility for desired species like Northern Pike while better regulating invasive Common Carp spawning migration and use of these systems.

Leveraging the value of conservation physiology for ecological restoration

The incorporation of conservation physiology into environmental management, particularly ecological restoration, is underutilized, despite the capacity of such approaches to discern how populations respond to the challenges of unpredictable and potentially inhospitable environments. We explore several examples where detailed mechanistic understanding of the physiological constraints of keystone and foundational species, ecological service providers such as insect pollinators, and species of conservation concern has been used to optimize the return of these species to landscapes following the cessation of mineral extraction. Using such data can optimize the rapid return of functioning ecosystems during restoration or increase the conservation value of restoration by returning insurance populations of threatened species. Integrating this level of mechanistic understanding with fine‐resolution spatial data in the form of biophysical modeling can help plan recovery and identify targets that can subsequently be used in assessing restoration success, particularly in situations that require substantial investment over long periods, such as post‐mining restoration. There is growing recognition of the valuable insights offered by conservation physiology to broader practice and policy development, and there have been substantial technical developments in conservation physiology leading up to and into the twenty‐first century as a result. The global challenge facing restoration ecology has, however, also grown in that time. Rapidly and efficiently meeting ambitious global restoration objectives will require a targeted approach, and we suggest that the application of physiological data will be most strategic for rare species, keystone species, and ecosystem service providers more broadly.

Diversity of herpetofauna at restored cranberry bogs: A comparative survey of herpetofaunal diversity at a restored wetland in comparison to a retired cranberry bog to assess the restoration success

Wetlands perform critical ecological functions and provide wildlife habitats. Yet, wetland degradation continues at a global scale. In Massachusetts, USA, wetland restoration has reached remarkable heights, partly promoted by the retirement of cranberry bogs. In this study, to assess the effectiveness of cranberry-farm restoration for conservation of native herpetofauna, we surveyed both retired and restored cranberry bogs in south-eastern Massachusetts. Using both visual encounter surveys and baited aquatic traps, we documented herpetofaunal species and their relative abundance. Both survey methods combined, the cumulative herpetofaunal species richness at the restored bogs (16) exceeded that of the retired bogs (11). Our trap surveys indicated that the amphibian species richness at the retired bog was significantly greater than that of the restored bog. In contrast, reptilian species richness as well as the relative abundance of both amphibians and reptiles were significantly greater at the restored bog compared to the retired bog. Subsequent analyses we performed identified that greater habitat heterogeneity emerging from active restoration intervention was the underlying driver of elevated richness and abundance. Most frequently encountered herpetofauna at the restored versus retired bogs were habitat generalists with broader geographic ranges and are not of conservation concern. Our findings suggest that the restored bog we monitored is still in the early-recovery phase after active intervention. We urge the need for long-term herpetofaunal inventories via systematic, standard surveys to assess restoration success.

A systematic review of the global freshwater mussel restoration toolbox

Abstract Halting the global decline of freshwater mussels requires an improved understanding of the restoration approaches currently in use and the identification of shortcomings to inform the development of new ones. This article reviews published evaluations of restoration efforts on the ground and those identified or proposed in the literature. This review found few reports of the effectiveness of restoration measures, and of those reported there was strong temporal and geographical bias. Reports were mostly recent and took place within mussel‐diverse regions of the Global North (i.e. North America, Europe). Efforts focused on population support encompassed relocation, translocation and population augmentation from captive breeding, and potential restoration approaches emphasized planning and prioritization. It was challenging to assess restoration success owing to differences in success metrics and varied lengths of post‐restoration monitoring. Some measures were inherently more species specific, such as population support, but some articles suggested that the use of multiple measures may allow more species to be addressed by restoration efforts. Consistent documentation and reporting of restoration measures – including failed ones – are needed to advance freshwater mussel restoration. In addition, continued work is needed to accelerate and better align the development and use of restoration approaches for freshwater mussels. Reporting of unsuccessful or partially successful attempts does not adequately reflect the long life histories of freshwater mussels. Investigation of the contexts where approaches have been effective (even partially), and concerted efforts to implement combinations of measures at a catchment scale are critical for unionids globally. As such, recommendations are posed to aid integration of research and practice to advance and further develop freshwater mussel restoration.

Active restoration fosters better recovery of tropical rainforest birds than natural regeneration in degraded forest fragments

Abstract Ecological restoration has emerged as a key strategy for conserving tropical forests and habitat specialists, and monitoring faunal recovery using indicator taxa like birds can help assess restoration success. Few studies have examined, however, whether active restoration (AR) achieves better recovery of bird communities than natural regeneration, or how bird recovery relates to habitat affiliations of species in the community. In rainforests restored over the past two decades in a fragmented landscape (Western Ghats, India), we examined whether bird species richness and community composition recovery in 23 actively restored (AR) sites were significantly better than recovery in paired naturally regenerating (NR) sites, relative to 23 undisturbed benchmark (BM) rainforests. We measured eight habitat variables and tested whether bird recovery tracked habitat recovery, whether rainforest and open‐country birds showed contrasting patterns, and assessed species‐level responses to restoration. We recorded 92 bird species in 460 point‐count surveys. Rainforest bird species richness was highest in BM, intermediate in AR and lowest in NR. Contrastingly, open‐country bird species richness was least in BM, intermediate in AR and highest in NR. Bird community composition varied significantly across treatment types with composition in AR in transition from NR to BM. Bird community dissimilarity between sites was positively related to dissimilarity in habitat structure and floristics, and geographical distance between sites. Variance partitioning indicated that structural and floristic dissimilarity explained 90% of the variation in community composition. Indicator species analysis revealed significant associations of 34 species with one or more treatment types. Species associated with BM and AR treatment types were all rainforest species, while only 38% of species associated with AR and NR treatment types were rainforest species. Synthesis and applications. We show that active restoration (AR) of degraded fragments benefits rainforest birds and reduces the infiltration of open‐country birds, and highlight the importance of considering rainforest and open‐country species separately. In human‐modified tropical rainforest landscapes, AR of degraded fragments fosters partial recovery and complements protection of mature forests for bird conservation.

Restoration of riparian vegetation on a mountain river degraded by historical mining and grazing

AbstractRiparian ecosystems in montane areas have been degraded by mining, streamflow alterations, and livestock grazing. Restoration of ecological and economic functions, especially in high‐elevation watersheds that supply water to lower elevation urban and agriculture areas is of high priority. We investigated the response of riparian vegetation and bank stability following channel treatments and riparian habitat restoration along a segment of the upper Arkansas River south of Leadville, Colorado. The study area has been historically degraded by heavy‐metal mining and is designated a U.S. Superfund site. Additionally, trans‐basin water diversions and livestock grazing have contributed to channel widening and altered vegetation composition and cover. We used a before‐after‐control impact study design in four reaches with varied contamination and grazing history to assess restoration success. Before restoration, streambanks were dominated by graminoids and total vegetation cover varied among reaches with willow cover less than 16% in three reaches. Post‐restoration, changes in total vegetation cover fell short of projected goals, but willow cover was greater than 20% in all study reaches. The increase in woody cover likely contributed to reduced erosion and vegetation encroachment post‐restoration. Differences in functional group cover among reaches persisted post‐restoration and may be attributed to soil contamination levels and low willow seed rain and dispersal. These results highlight the importance of setting realistic restoration goals based on elevation and past land use. We recommend further remediation of fluvial tailings with low vegetation cover and continued monitoring of willow height and cover to determine if further restoration activities are needed.

Bottom-up cascading effects of quarry revegetation deplete bird-mediated seed dispersal services

Quarrying activities cause profound modifications on ecosystems, such as removal of vegetation cover, biodiversity loss and depletion of ecosystem services. Ecological restoration stands as a solution to revert such effects. Concomitantly, awareness is currently being given on ecosystem services and ecological processes to evaluate restoration efficiency.The objective of the study was to assess restoration success in a quarry subjected to restoration practices for the last 40 years involving the plantation of native Mediterranean vegetation and the non-native Aleppo pine Pinus halepensis. The study was carried out by assessing the effectiveness of seed dispersal service provided by birds in the restored quarry by comparing this service to neighbouring natural (shrubland) and other semi-natural areas (oak-pine mixed open and Aleppo pine forest) present at the landscape. For this purpose, we explored bird composition structure and seed dispersal networks using point counts and faecal samples of mist-netted birds. We also collected vegetation structure data and explored its effect on bird community composition.Our results showed that bird abundance in the restored quarry was significantly lower, and its bird community was compositionally different than natural shrubland and semi-natural areas. For instance, seed-dispersing birds, woody and shrub/ground foragers and partially migrators were the most affected groups at the restored area. Bird community composition and their traits were likely driven by vegetation characteristics, with higher native vegetation cover and fruit richness promoting higher bird abundance and Aleppo pine cover negatively influencing seed-dispersing birds. Concurrently, seed dispersal network in the restored quarry was less complex than in other areas.Seed dispersal services in the restored quarry were below the reported values for neighbouring natural and semi-natural areas and are likely driven by the low abundance of seed-dispersing birds. We consider that the causes affecting this group's low abundance can be related to revegetation measures favouring Aleppo pine, combined with a shallow soil depth and poor soil quality, which may have constrained native vegetation development.We conclude that seed dispersal services at the quarry are depleted, which may suggest a low restoration success concerning ecosystem functioning. Our results strengthen that quarry revegetation with non-native species must be avoided, since it alters bird community composition, and consequently, affects seed dispersal service provided by birds.

Long-term monitoring reveals convergent patterns of recovery from mining contamination across 4 western US watersheds

Long-term studies of stream ecosystems are essential for assessing restoration success because they allow researchers to quantify recovery trajectories, gauge the relative influence of episodic events, and determine the time required to achieve clean-up objectives. To quantify responses of benthic macroinvertebrate assemblages to stream remediation, we integrated results of 4 long-term (20–29 y) assessments of mining-impacted watersheds that were broadly distributed across the western US (California, Colorado, Idaho, Montana). Using a before–after control–impact (BACI) study design, we observed substantial reductions in metal concentrations and corresponding improvements of benthic assemblages following remediation. Recovery rates were relatively consistent, and streams typically recovered within 10 to 15 y after remediation was initiated (mean = 10.25 y), although episodic events changed trajectories at some sites. Differences in recovery among watersheds were likely determined by a number of factors, including the severity of contamination, effectiveness of remediation, proximity to upstream sources of colonization, and hydrologic variation. We also observed considerable variation in the rate and extent of recovery among assemblage metrics. For example, total abundance and richness recovered rapidly at most sites, but the composition of benthic macroinvertebrate assemblages remained substantially altered compared with reference sites. Using piecewise linear regression, we estimated a threshold response of Ephemeroptera, Plecoptera, and Trichoptera (EPT) species richness at ~1 cumulative criteria unit (CCU), which is the sum of the fractions of chronic water-quality criteria for metals measured, suggesting this value was protective of benthic assemblages. However, EPT richness was reduced by ~20% at 2× this CCU value, indicating that moderate exceedances of water-quality criteria could substantially affect stream biodiversity. Non-metric multidimensional scaling analyses identified common sets of species trait states across the 4 watersheds that were associated with either metal contamination or with recovering and intact reference stream assemblages. Our study illustrates the importance of long-term studies for quantifying responses to stream restoration and the usefulness of BACI designs for demonstrating cause-and-effect relationships between restoration treatments and community recovery. Because these 4 watersheds were among the most severely polluted sites in the western US, our study demonstrates the value of these investments in watershed restoration and the potential for success under the most extreme conditions.

A conceptual framework for urban ecological restoration and rehabilitation

Urban greenspace has gained considerable attention during the last decades because of its relevance to wildlife conservation, human welfare, and climate change adaptation. Biodiversity loss and ecosystem degradation worldwide require the formation of new concepts of ecological restoration and rehabilitation aimed at improving ecosystem functions, services, and biodiversity conservation in cities. Although relict sites of natural and semi-natural ecosystems can be found in urban areas, environmental conditions and species composition of most urban ecosystems are highly modified, inducing the development of novel and hybrid ecosystems. A consequence of this ecological novelty is the lack of (semi-) natural reference systems available for defining restoration targets and assessing restoration success in urban areas. This hampers the implementation of ecological restoration in cities. In consideration of these challenges, we present a new conceptual framework that provides guidance and support for urban ecological restoration and rehabilitation by formulating restoration targets for different levels of ecological novelty (i.e., historic, hybrid, and novel ecosystems). To facilitate the restoration and rehabilitation of novel urban ecosystems, we recommend using established species-rich and well-functioning urban ecosystems as reference. Such urban reference systems are likely to be present in many cities. Highlighting their value in comparison to degraded ecosystems can stimulate and guide restoration initiatives. As urban restoration approaches must consider local history and site conditions, as well as citizens’ needs, it may also be advisable to focus the restoration of strongly altered urban ecosystems on selected ecosystem functions, services and/or biodiversity values. Ecosystem restoration and rehabilitation in cities can be either relatively inexpensive or costly, but even expensive measures can pay off when they effectively improve ecosystem services such as climate change mitigation or recreation. Successful re‐shaping and re-thinking of urban greenspace by involving citizens and other stakeholders will help to make our cities more sustainable in the future.

Changes in motile benthic faunal community structure following large-scale oyster reef restoration in a subtropical estuary

Restored oyster reefs support diverse communities of motile benthic organisms (small fishes and macroinvertebrates). These communities represent a critical component of estuarine food webs and frequently include juveniles of ecologically and economically important species that utilize oyster reefs as nurseries. Oyster-related metrics are commonly used to quantify restoration success, yet it is also important to examine communities of oyster-associated organisms when attempting to identify ecological convergence between natural and restored oyster reefs. Here, we compare the community composition of motile benthic organisms over time at one restored and three natural oyster (Crassostrea virginica) reefs in the Loxahatchee River estuary (Florida, USA) as one means of assessing restoration success. We also examine the effects of vertical relief on motile benthic organisms following restoration. The community of motile benthic organisms at the 1.93-ha restoration reef gradually began to resemble natural communities in the months following reef construction. Within ~22 months, biomass and community composition were similar between natural and restored habitats. At that point, the mean biomass of motile benthic organisms at the restoration site had reached 83.6 g/m2 (versus 89.8 g/m2 at nearby natural reefs), and the restored reef supported >1600 kg of small, motile, oyster-associated organisms. Biomass values increased more rapidly in high-relief sections of the restored reef (30 cm vs. 15 cm reef height), particularly during the first year following restoration. High-relief areas were also characterized by increased oyster densities, greater oyster-generated rugosity, and decreased sedimentation. Our findings suggest that small differences in reef design can have important implications for restoration success as well as food web structure and dynamics via shifts in community composition.

Fruit bat diversity patterns for assessing restoration success in reforestation areas in the Philippines

In response to extensive deforestation in the Philippines in the last century, reforestation initiatives have been developed, setting area- or seedling count-based success criteria. However, to sufficiently assess reforestation as an approach to conserving biodiversity and protecting habitats, restoration of ecosystem integrity must be evaluated. Increased recognition of the role of fauna in ecological restoration has led to the evaluation of the role of different groups in assisting recovery and as potential metrics of success. In this study, we used mist netting data to evaluate how richness, abundance, diversity, and composition of fruit bats differ between reforestation areas and nearby secondary forest, and their potential as measures of restoration success. We captured 6564 fruit bats representing 15 species from a sampling effort of 1,994,366 m2·h. Estimated species richness and Simpson indices did not differ significantly between habitat types. Overall abundance was only significantly different in Palinpinon, with more individuals in the reforestation area, while Shannon indices only differed significantly in BacMan. Differences in composition were all found to be statistically significant, based on non-metric multidimensional scaling ordination biplots and permutational MANOVA. Of the three most abundant species captured across all reservations, the generalists Cynopterus luzoniensis and Macroglossus minimus were more abundant in reforestation areas. On the other hand, the forest specialists Haplonycteris fischeri, Harpyionycteris whiteheadi, and Ptenochirus minor showed lower abundances in reforestation areas. While univariate biodiversity metrics did not differ between secondary forests and reforestation areas, the abundance of particular species and the species composition of fruit bats remained distinct between these habitats. We identified specific aspects of the fruit bat assemblage with the potential as metrics of restoration success. To facilitate evaluation of restoration success using changes in faunal assemblage, we recommend the development of sampling protocols and metrics that would standardize this process.

Recovering trophic structure through habitat restoration: A review

Restoration ecologists have long-called for more holistic approaches to ecosystem restoration and tools for monitoring restoration success. There has been an increased number of restoration projects assessing ecosystem-scale processes, such as nutrient cycling and productivity. However, an examination of trophic interactions (e.g., trophic position, linkages, and diversity) as a tool for assessing restoration success is limited and can provide a more complete depiction of restoration success when coupled with traditional community metrics. Here, the impact of habitat restoration on trophic recovery was assessed through a targeted literature review, analyzing how trophic structure responds to habitat restoration over time, compared to control sites, and viewed across ecosystems. Overall, trophic structure recovers following restoration but may require several years. Comparing systems, restoration of trophic structure in terrestrial environments has received less attention (19%) as compared to freshwater (31%) and coastal (50%) systems. Community metrics and stable isotopes were the most common methods for assessing trophic interactions and will likely continue to be valuable tools when assessing how restoration impacts ecosystems. In terms of best practices to achieve and quantify trophic restoration success, future studies should increase frequency and duration of pre- and post-restoration monitoring, establish consistency in selecting control sites, and incorporate habitat structural elements compatible with restoration to attract higher trophic level species. The inclusion of trophic interactions in restoration projects generates a more comprehensive understanding of trophic structure and ecosystem function and offers insights to develop more effective management strategies for achieving long-term restoration success.