Restoration Challenges Research Articles

Adapting management to a changing world: Warm temperatures, dry soil, and interannual variability limit restoration success of a dominant woody shrub in temperate drylands.

Restoration and rehabilitation of native vegetation in dryland ecosystems, which encompass over 40% of terrestrial ecosystems, is a common challenge that continues to grow as wildfire and biological invasions transform dryland plant communities. The difficulty in part stems from low and variable precipitation, combined with limited understanding about how weather conditions influence restoration outcomes, and increasing recognition that one-time seeding approaches can fail if they do not occur during appropriate plant establishment conditions. The sagebrush biome, which once covered over 620,000km2 of western North America, is a prime example of a pressing dryland restoration challenge for which restoration success has been variable. We analyzed field data on Artemisia tridentata (big sagebrush) restoration collected at 771 plots in 177 wildfire sites across its western range, and used process-based ecohydrological modeling to identify factors leading to its establishment. Our results indicate big sagebrush occurrence is most strongly associated with relatively cool temperatures and wet soils in the first spring after seeding. In particular, the amount of winter snowpack, but not total precipitation, helped explain the availability of spring soil moisture and restoration success. We also find considerable interannual variability in the probability of sagebrush establishment. Adaptive management strategies that target seeding during cool, wet years or mitigate effects of variability through repeated seeding may improve the likelihood of successful restoration in dryland ecosystems. Given consistent projections of increasing temperatures, declining snowpack, and increasing weather variability throughout midlatitude drylands, weather-centric adaptive management approaches to restoration will be increasingly important for dryland restoration success.

Eutrophication, Research and Management History of the Shallow Ypacaraí Lake (Paraguay)

Ypacaraí Lake is the most renowned lake in landlocked Paraguay and a major source of drinking and irrigation water for neighbouring towns. Beyond its socioeconomic and cultural significance, it has great ecological importance, supporting a rich biodiversity. Rapid growth of human presence and activities within its basin has led to its environmental degradation, a heartfelt matter of high political concern that compels intervention. Here, by reconstructing the history of scientific and management-oriented research on this system, we provide a comprehensive assessment of current knowledge and practice to which we contribute our recent, novel findings. An upward trend in total phosphorus concentration confirms ongoing eutrophication of an already eutrophic system, evidenced by consistently high values of trophic state indices. Downward trends in water transparency and chlorophyll-a concentration support the hypothesis that primary production in this lake is fundamentally light limited. Statistical and other analyses suggest high sensitivity of the system to hydraulic, hydro-morphological and hydro-meteorological alterations arising, respectively, from engineering interventions, land use and climate change. By discussing knowledge gaps, opportunities for research and challenges for management and restoration, we argue that this case is of high scientific value and that its study can advance theoretical understanding of shallow subtropical lakes.

Building Resistance and Resilience: Regeneration Should Not be Left to Chance

Contemporary forest planning has tasked managers with developing goals associated with resistance and resilience. In practice, silviculturists use forest structure and tree species composition to characterize goals and desired future conditions, write prescriptions, and monitor outcomes associated with resistance and resilience. Although rarely discussed in the exploding literature relating to forest resistance and resilience, silvicultural regeneration methods are important and underutilized tools to meet these goals. We propose alternative silvicultural systems for building resistance and resilience to two common large-scale bark beetle disturbance agents in the Intermountain West, United States: mountain pine beetle (Dendroctonus ponderosae Hopkins) and spruce beetle (Dendroctonus rufipennis Kirby). Shelterwood, and shelterwood-with-reserves, silvicultural systems provide the desirable facilitative characteristics of a mature overstory on maintaining advance reproduction and the establishment of new cohorts of desirable tree species. These also allow the timely regeneration of large treatment areas necessary to rapidly promote desired future conditions in the face of inevitable disturbance. When implemented proactively, regeneration treatments allow silviculturists to take advantage of currently existing vegetation for the creation of age class and tree species diversity. In general, these examples illustrate the need for proactive planning for regeneration in response to any disturbance where desired future conditions include particular species. Furthermore, we argue that timely silvicultural interventions that focus on regenerating trees may be a key factor in achieving goals relating to resilience to specific disturbance types. Waiting until after the disturbance has occurred could result in the lost opportunity to establish desired species composition or stand structure—and may well result in a considerable restoration challenge.

Concepts, Challenges, and Emerging Themes of Restoration Ecology

Concepts, Challenges, and Emerging Themes of Restoration Ecology

Bird Reliefs with Feathers: Challenges of Conservation and Restoration of Natural History Objects on Paper

The subject of this work is the conservation and restoration of three watercolours with feathers, created by Michal Rymkiewicz in 1848, from the collection of the National Museum in Warsaw (Warsaw,...

Using simulation modeling to inform management of invasive species: A case study of eastern brook trout suppression and eradication

Ecosystem impacts due to invasive species continue to attract significant conservation effort worldwide. In aquatic ecosystems, physical interventions such as suppression and eradication of non-native species are typically expensive, long-term commitments, with few examples of lasting success in the absence of significant ongoing effort. Control of non-native species is a major conservation and restoration challenge, as a species' demographic resilience and connectivity within networks can limit the ability of suppression or eradication efforts to influence populations. Simulation tools can provide valuable insights for the management of these systems - from evaluation of tradeoffs between time and effort to prediction of relative success rates of alternative strategies in changing environments. In the Pacific Northwest region of the U.S., the eastern brook trout (EBT; Salvelinus fontinalis) is a non-native invasive species that competes with native fish species across a wide spatial scale due to extensive human-mediated introduction starting in the early 20th century. The goal of this study was to simulate the individual movement and demographics of EBT before, during, and following implementation of control efforts in tributaries within the Pend Oreille River watershed. The ultimate purpose of the model was to inform mitigation decisions through the investigation of alternative management actions in an adaptive management framework. Our results indicate that eradication of EBT is improbable in large systems via electrofishing, but suppression is a viable alternative given sustained management efforts. Changes to scheduling, effort, and length of electrofishing suppression treatments had minimal effects on EBT population recovery times. We reproduced the effects of compensatory responses to control treatments, including increases in juvenile survival and emigration rates, and demonstrated that these mechanisms are likely drivers of recovery following treatment. Our study highlights the many benefits of incorporating spatially explicit, individual-based models into management plans for the control of invasive species.

The Interactive Effect of Multiple Stressors on Crustacean Zooplankton Communities in Montane Lakes

AbstractNonnative fish introductions have altered thousands of naturally fishless montane lakes, resulting in cascading food web repercussions. Nitrogen deposition has been recognized as an anthropogenic contributor to acidification and eutrophication of freshwater ecosystems, which may affect the abundance and composition of planktonic communities. This study identified responses of zooplankton communities from two lakes (fish present versus absent) in Mount Rainier National Park to manipulations simulating an episodic disturbance of acidification and eutrophication via nitrogen addition in mesocosms. Zooplankton communities from lakes with different food web structure (i.e., fish present or absent) responded differently to the singular effects of acid and nitrogen addition. For instance, zooplankton biomass decreased in the acid treatment of the fishless lake experiment, but increased in response to acid in the fish‐present experiment. In contrast, the combination of acid and nitrogen often resulted in weak responses for both lake types, resulting in nonadditive effects, i.e., the net effect of the stressors was in the opposite direction than predicted, which is known as a reversal or “ecological surprise.” This experiment demonstrates the difficulty in predicting the interactive effects of multiple stressors on aquatic communities, which may pose significant challenges for habitat restoration through fish removal.

Conjoint Use of Chemical Amendments and Municipal Solid Waste Compost for Amelioration of Degraded Sodic Soil

Presence of salts in soil is one of the major challenges for restoration of degraded sodic lands. Reclamation of these soils through chemical amendments like gypsum and phosphogypsum is too expensive for marginal farmers. To provide a realistic solution for ameliorating sodic soils, through conjoint use of lower dose of chemical amendments with municipal solid waste (MSW) compost, a field experiment was conducted during 2015–16 to 2017–18 at ICAR-CSSRI, Research farm, Shivri, Lucknow (26°47′58′′ N, 80°46′24′′ E). The experiment was conducted on highly sodic soil having pH2 9.8, EC2 1.47 dS m−1, and ESP 78. Reduced dose of gypsum or phosphogypsum @ 25% of gypsum requirement (GR) in combination with MSW compost @10 t ha−1 resulted in significant improvement in the soil physical, chemical and microbial properties over the recommended dose of gypsum or phosphogypsum (50% of GR). Combined use of gypsum or phosphogypsum @ 25% of recommended dose of gypsum along with MSW compost @ 10 t ha−1 increased about 10% soil organic carbon content, 13% available N, 42% bacterial population and 200% fungal population; and reduced 14% exchangeable sodium percentage over the recommended dose of inorganic amendments. With the application of gypsum @ 25% GR + on-farm MSW compost @ 10 t ha−1, the soil bulk density decreased by 11% and the infiltration rate increased by 54% as compared to initial values. With the introduction of this approach there is saving of about 50% amount of inorganic amendments that can be utilized to reclaim double the degraded sodic lands and improve food security of resource poor farmers in the region. This also saved about 35.6% reclamation cost on account of reducing gypsum dose.

Light requirements for successful restoration of eelgrass (Zostera marina L.) in a high latitude environment – Acclimatization, growth and carbohydrate storage

The short growth season in high latitude environments pose challenges for eelgrass restoration, particularly in areas that receive little light due to e.g. depth or reduced water quality conditions. In order to improve our understanding of the acclimatization potential of eelgrass to low light and the light requirement for successful restoration of eelgrass, an indoor mesocosm study was performed assessing three light (3, 5 and 10mol photons m−2day−1) and two temperature conditions (12 and 20°C). The aim of the study was to determine if eelgrass transplants originating from a shallow donor meadow with high light could acclimatize to low light conditions and how different light conditions affect growth characteristics and carbohydrate storage of transplants. A second aim was to investigate how eelgrass grown under different light conditions cope during severe shading (zero light) under the two temperature conditions, and how severe shading affect the carbohydrate stock of transplants. The results demonstrate that eelgrass can acclimatize to light levels from 10 down to 3mol photons m−2day−1 by adjustments in morphology, pigmentation and growth strategy, but with a significant reduction in the production of lateral branches below 5mol photons m−2day−1. Temperature had a strong positive effect on shoot morphology and above ground biomass production independent of light treatment, but less effect on branching. Furthermore, the study shows that acclimatized eelgrass transplants can store carbohydrates at light levels down to 3mol photons m−2day−1, but that losses occur in relation to the transplantation process and as a result of severe shading. Survival of transplants during severe shading conditions demonstrated large temperature dependent effects, with no effects of previous light conditions. The results from this study provide important insight into the phenotypic response by eelgrass to environmental conditions and could have important implications for management and restoration of eelgrass in high latitude environments with respect to acclimatization potential and the minimum light requirement for successful restoration.

How to make complexity look simple? Conveying ecosystems restoration complexity for socio-economic research and public engagement.

Ecosystems degradation represents one of the major global challenges at the present time, threating people’s livelihoods and well-being worldwide. Ecosystem restoration therefore seems no longer an option, but an imperative. Restoration challenges are such that a dialogue has begun on the need to re-shape restoration as a science. A critical aspect of that reshaping process is the acceptance that restoration science and practice needs to be coupled with socio-economic research and public engagement. This inescapably means conveying complex ecosystem’s information in a way that is accessible to the wider public. In this paper we take up this challenge with the ultimate aim of contributing to making a step change in science’s contribution to ecosystems restoration practice. Using peatlands as a paradigmatically complex ecosystem, we put in place a transdisciplinary process to articulate a description of the processes and outcomes of restoration that can be understood widely by the public. We provide evidence of the usefulness of the process and tools in addressing four key challenges relevant to restoration of any complex ecosystem: (1) how to represent restoration outcomes; (2) how to establish a restoration reference; (3) how to cope with varying restoration time-lags and (4) how to define spatial units for restoration. This evidence includes the way the process resulted in the creation of materials that are now being used by restoration practitioners for communication with the public and in other research contexts. Our main contribution is of an epistemological nature: while ecosystem services-based approaches have enhanced the integration of academic disciplines and non-specialist knowledge, this has so far only followed one direction (from the biophysical underpinning to the description of ecosystem services and their appreciation by the public). We propose that it is the mix of approaches and epistemological directions (including from the public to the biophysical parameters) what will make a definitive contribution to restoration practice.

Will hypolimnetic waters become anoxic in all deep tropical lakes?

To elucidate trends of hypolimnetic oxygen concentrations, vertical distributions of dissolved oxygen were measured in eight deep tropical bodies of water (one natural lake with two basins, five natural lakes, and one reservoir) in Indonesia. A comparison of those concentrations with previously reported data revealed that shoaling of hypolimnetic oxygen-deficient (around a few decimeters to a few meter per year) water had occurred in all of the lakes. Calculated areal hypolimnetic oxygen depletion rates were 0.046–5.9 g m−2 y−1. The oligomictic or meromictic characteristics of the bodies of water suppressed circulation and mixing in the hypolimnions and thus resulted in continuous shoaling of the uppermost oxygen-deficient layers. In some lakes, millions of fish sometimes died suddenly, probably owing to upward movement of oxygen-deficient water to near the surface during periods of strong winds. In the future, the rate of shoaling will be accelerated by human impacts in the basins and by climate warming, the influence of which has already been manifested by rising water temperatures in these lakes. Appropriate monitoring and discussions of future restoration challenges are urgently needed to prevent the hypolimnions of the lakes from becoming completely anoxic.

Where to from here? Challenges for restoration and revegetation in a fast-changing world

Ecological restoration provides hope and the opportunity for positive action in the face of ongoing rapid environmental change. Restoration techniques and approaches are improving, and restoration is seen as an important element of conservation management and policy from local to global scales. Motivations for undertaking restoration are numerous, and resources available for this enterprise vary greatly from case to case. Restoration encompasses everything from multinational companies restoring minesites or offsets to comply with environmental regulations to local bushcare groups doing voluntary work in their local patch of bush. The financial and human resources available largely determine the extent and type of restoration activities that are possible. An important task is increasing the resources available for these activities, but it is also important to recognise that resources will continue to fall well short of what is actually required into the foreseeable future. In addition, the need for restoration will only increase with ongoing development and changing environments. In this scenario, how then, should decisions be made about what types of restoration activities are appropriate and possible? How do we ensure that the good intentions behind restoration management and policy translate into good outcomes? Challenges for restoration include not only improving the techniques and approaches but also tackling hard questions about what restoration goals are appropriate and engaging in open discussion of hidden assumptions and values behind decisions.

Antibacterial efficacy of triple-layered poly(lactic-co-glycolic acid)/nanoapatite/lauric acid guided bone regeneration membrane on periodontal bacteria.

A guided bone regeneration (GBR) membrane has been extensively used in the repair and regeneration of damaged periodontal tissues. One of the main challenges of GBR restoration is bacterial colonization on the membrane, constitutes to premature membrane degradation. Therefore, the purpose of this study was to investigate the antibacterial efficacy of triple-layered GBR membrane composed of poly(lactic-co-glycolic acid) (PLGA), nanoapatite (NAp) and lauric acid (LA) with two types of Gram-negative periodontal bacteria, Fusobacterium nucleatum and Porphyromonas gingivalis through a disc diffusion and bacterial count tests. The membranes exhibited a pattern of growth inhibition and killing effect against both bacteria. The increase in LA concentration tended to increase the bactericidal activities which indicated by higher diameter of inhibition zone and higher antibacterial percentage. It is shown that the incorporation of LA into the GBR membrane has retarded the growth and proliferation of Gram-negative periodontal bacteria for the treatment of periodontal disease.

The age of restoration: challenges presented by dryland systems

Intact drylands are highly evolved and complex ecosystems, which allow them to be productive despite harsh environmental conditions. However, drylands are particularly susceptible to degradation, even after minor disturbance events. Conditions for natural plant recruitment in dryland systems are spatially and temporally irregular, which can create challenges for restoration. Large-scale restoration and rehabilitation of dryland ecosystems have become a global concern, prompted by ever-increasing anthropogenic pressure and associated degradation of these natural systems worldwide. The success of plant reestablishment programs in these regions is closely linked to both ecological and socioeconomic opportunities and limitations. This special issue brings together papers that discuss the roles which ecological and socioeconomic factors play in influencing dryland ecosystem restoration outcomes. We aim to (1) highlight the current status of recovery efforts taking place across a range of dryland ecosystems, emphasize advances in the region-specific understanding of plant community development, and (2) provide comparisons between the primary drivers and limitations to restoration that exist across dryland systems.

Rescue of American chestnut with extraspecific genes following its destruction by a naturalized pathogen

Following the near-obliteration of American chestnut (Castanea dentata [Marsh.] Borkh.) by the chestnut blight early in the last century, interest in its restoration has been revived by efforts to develop a blight-resistant form of the species. We summarize progress and outline future steps in two approaches: (1) a system of hybridizing with a blight-resistant chestnut species and then backcrossing repeatedly to recover the American type and (2) transformation of American chestnut with a resistance-conferring transgene followed by propagation and conventional breeding. Several decades of effort have been invested in each approach. More work remains, but results indicate that success is within practical reach. The restoration of C. dentata to its native habitat now appears to be less a matter of time and conjecture than ever before in 90 years of work by public and private entities. The difficult and protracted task of incorporating extraspecific genes for resistance into a tree species with lethal susceptibility to a naturalized pathogen represents perhaps the most extreme of restoration challenges. Its pursuit by a small non-governmental organization supported primarily by philanthropy and volunteers may serve as a model for other species threatened by exotic pathogens or insects.

Optimizing seed mixture diversity and seeding rates for grassland restoration

AbstractRevegetation by seeding is an important tool in restoration. Seeding practices for restoration often rely on standard prescriptions for seed mix diversity and seeding rates. Seed mix diversity and rates are generally low within restoration projects and these practices are typically not informed by research. The objective of this study was to explore a new method for determining an optimal seed mix diversity and seeding rate for restoration of a semiarid grassland. We examined restoration success associated with differing seed mix diversity levels (5–50 species) and seeding rates (400–1,600 pure live seeds [PLS]/m2) using a response surface regression (RSR) experimental design at 12 disturbed sites in northeastern Colorado. Overall restoration success was evaluated based on optimizing desirability across nine individual responses: biomass and diversity of seeded, volunteer native, noxious, non‐native species, and the density of seeded species. Greatest restoration success after four growing seasons occurred at a seed mix diversity of 35 species and a seeding rate of 1,366PLS/m2.RSRexperimental design and analysis has seldom been used to answer ecological questions. This novel approach to address a pressing restoration challenge provided unique insight into how seed mix diversity and seeding rate, singly or in combination, influence the first 4 years of plant community development and overall restoration success. These results suggest that including more native species and seeding at higher rates than current practice could lead to greater restoration success in grasslands.

How economics can further the success of ecological restoration.

Restoration scientists and practitioners have recently begun to include economic and social aspects in the design and investment decisions for restoration projects. With few exceptions, ecological restoration studies that include economics focus solely on evaluating costs of restoration projects. However, economic principles, tools, and instruments can be applied to a range of other factors that affect project success. We considered the relevance of applying economics to address 4 key challenges of ecological restoration: assessing social and economic benefits, estimating overall costs, project prioritization and selection, and long-term financing of restoration programs. We found it is uncommon to consider all types of benefits (such as nonmarket values) and costs (such as transaction costs) in restoration programs. Total benefit of a restoration project can be estimated using market prices and various nonmarket valuation techniques. Total cost of a project can be estimated using methods based on property or land-sale prices, such as hedonic pricing method and organizational surveys. Securing continuous (or long-term) funding is also vital to accomplishing restoration goals and can be achieved by establishing synergy with existing programs, public-private partnerships, and financing through taxation.

Seed production areas for the global restoration challenge.

Wild-collected seed can no longer meet global demand in restoration. Dedicated Seed Production Areas (SPA) for restoration are needed and these require application of ecological, economic, and population-genetic science. SPA design and construction must embrace the ecological sustainability principles of restoration.

An overview of the progress and challenges of peatland restoration in Western Europe

AbstractPeatlands are the most efficient terrestrial carbon store on Earth, and deliver multiple other ecosystem services including climate regulation, water purification, preservation of ecological and archaeological records, etc. Disturbed and degraded peatlands do not provide the same ecological services and thus bear a significant cost to society. Because this cost may be alleviated by appropriate restoration measures, money is being invested in peatland restoration projects around the world. Here, we review over 25 years of restoration in Western Europe. First, we provide an overview of techniques used in different contexts and evaluate the status of the evidence base for restoration outcomes. Between 1993 and 2015, the EU‐LIFE nature programme alone invested 167.6M € in 80 projects, which aim to restore over 913 km2 of peatland habitats in Western European countries, mostly in protected sites part of the Natura 2000 EU network. This represents less than 2% of the total remaining area of peatlands in these countries, most of which have been impacted to some degree by anthropogenic disturbances. Potential for restoration should be considered in nondesignated sites. We reviewed a number of case studies covering a range of restoration approaches used in different parts of Western Europe. We found that published evidence of restoration progress was limited to specific sites/areas, and in many cases lacked baseline measurements and clear goals, that is, measurable target or contemporary reference(s). We discuss barriers and opportunities to turn the tide for peatland restoration in Western Europe and promote the establishment of robust, standardized monitoring schemes.

Meeting Forest Restoration Challenges: Using the Target Plant Concept

Meeting forest restoration challenges relies on successful establishment of plant materials (e.g., seeds, cuttings, rooted cuttings, or seedlings, etc.; hereafter simply “seedlings”). The Target Plant Concept (TPC) provides a flexible framework that nursery managers and their clients can use to improve the survival and growth of these seedlings. The key tenets of the TPC are that (1) more emphasis is placed on how seedlings perform on the outplanting site rather than on nursery performance, (2) a partnership exists between the nursery manager and the client to determine the target plant based on site characteristics, and (3) that information gleaned from post-planting monitoring is used to improve subsequent plant materials. Through the nursery manager–client partnership, answers to a matrix of interrelated questions define a target plant to meet the reforestation or forest restoration objectives. These questions focus on project objectives; site characteristics, limiting factors, and possible mitigation efforts; species and genetic criteria; stocktype; outplanting tools and techniques; and outplanting window. We provide examples from the southeastern United States, Hawai‛i, and Lebanon on how the TPC process has improved performance of seedlings deployed for reforestation and forest restoration.