Semiochemicals and habitat manipulation to support green lacewing activity to reduce aphid infestations in agroecosystems

Conservation biological control (CBC) is a promising tool for ecological intensification that aims to establish resilient natural enemy populations that contribute to pest management with reduced use of pesticides and at the same time support native biodiversity in agroecosystems. Yet the impact of natural enemies in CBC is often limited due to missing resources such as food, habitat, and hibernation shelters. Here, we studied a CBC strategy that incorporates these essential resources combined with semiochemicals, focusing on how the common green lacewing can enhance biological control of aphids.In a 4-year field study conducted at three locations in the region of East Norway, we developed a CBC strategy combining the three measures ATTRACT (a ternary attractant that increase lacewing egg laying), FOOD (floral buffer strips), and SHELTER (insect hotels for overwintering survival) to increase aphid biological control in spring barley. We recorded the number of lacewings, ladybirds, hoverflies, parasitized aphid mummies, and the two cereal aphid species Sitobion avenae and Rhopalosiphum padi. Our CBC strategy resulted in a significant increase in lacewing activity and significant aphid suppression. At all three locations and over the 4-year period, aphid infestation was below the economic damage threshold in the field plots using CBC measures. In contrast, during two of the years, the density of the aphid infestation in the control plots was significantly above the damage threshold. We found evidence that use of the ternary attractant supported green lacewings but led to loss of ladybirds, hoverflies, and parasitoids, even though flower strips were used as alternative resources.Our study shows a promising increase in lacewing activity in the agricultural landscape and high biological control of aphids in barley. Long-term field studies are needed to evaluate the impact on non-target species and the agroecosystem before practical application of this approach can be considered.     

Arbuscular Mycorrhizal Fungi as Components of Sustainable Soil-Plant Systems

Abstract

Increased pressure for food production has, in recent years, led to the development of intensive agricultural systems that use significant quantities of inorganic fertilizers and pesticides. However, there is now substantial evidence for the environmental costs of this high-input strategy and this has led to demands for agricultural systems to be modified in order to make them more sustainable. Arbuscular mycorrhizal fungi (AMF) play a key role in natural and agricultural ecosystems through major functions in the enhancement of plant phosphorus and nitrogen nutrition, nutrient and soil conservation, and the biological control of plant pathogens. They are essential to the sustainability of systems and their importance in agricultural ecosystems is likely to increase as inputs are reduced and/or rationalized. In order to maximize their benefits it is essential to ensure that management practices include minimum tillage, reduced use of inappropriate fertilizer, appropriate crop rotations with minimal fallow, and rationalized pesticide use. Furthermore, crop breeders should take full account of the symbiosis in selection. Future research should be targeted to understanding the functional ecology of AMF in agroecosystems.     

Nanotechnology and chemical engineering as a tool to bioprocess microalgae for its applications in therapeutics and bioresource management

Abstract

Microalgae are a dynamic biological resource with various biotechnological applications. During recent times, the scope of this application has expanded to include: nutritional health foods, pharmaceuticals, agricultural and industrial products, environmental remediation and bioenergy production. At the same time, the methods and technologies to bioprocess microalgae for the intended applications have also evolved. However, there are still significant developments needed to reach the full potential of microalgae. The presented review discusses current methodologies to improve the effectiveness of algal feedstocks by bioprocessing them innovatively with cost-effective and environmentally sustainable techniques for their applications in therapeutics and bioresource management. The first section discusses the diversity of microalgae and its applications. In following sections, bioprocessing microalgae for their applications in therapeutics focusing on the efficacy of algae-mediated metallic nanoparticles against microbial infections and cancer is discussed. In addition, a discussion on bioresource management to produce value-added products for bioenergy and bioresource conservation elaborated the potential of microalgae as a biological reservoir to resolve the energy crisis for the modern world.     

Biological control of invasive stink bugs: review of global state and future prospects

Invasive stink bugs (Hemiptera: Pentatomidae) are responsible for high economic losses to agriculture on a global scale. The most important species, dating from recent to old invasions, include Bagrada hilaris (Burmeister), Halyomorpha halys (Stål), Piezodorus guildinii (Westwood), Nezara viridula (L.), and Murgantia histrionica (Hahn). Bagrada hilaris, H. halys, and N. viridula are now almost globally distributed. Biological control of these pests faces a complex set of challenges that must be addressed to maintain pest populations below the economic injury level. Several case studies of classical and conservation biological control of invasive stink bugs are reported here. The most common parasitoids in their geographical area of origin are egg parasitoids (Hymenoptera: Scelionidae, Encyrtidae, and Eupelmidae). Additionally, native parasitoids of adult stink bugs (Diptera: Tachinidae) have in some cases adapted to the novel hosts in the invaded area and native predators are known to prey on the various instars. Improving the efficacy of biocontrol agents is possible through conservation biological control techniques and exploitation of their chemical ecology. Moreover, integration of biological control with other techniques, such as behavioural manipulation of adult stink bugs and plant resistance, may be a sustainable pest control method within organic farming and integrated pest management programs. However, additional field studies are needed to verify the efficacy of these novel methods and transfer them from research to application.     

Predictor species: Improving assessments of rare species occurrence by modeling environmental co‐responses

Designing an effective conservation strategy requires understanding where rare species are located. Because rare species can be difficult to find, ecologists often identify other species called conservation surrogates that can help inform the distribution of rare species. Species distribution models typically rely on environmental data when predicting the occurrence of species, neglecting the effect of species' co‐occurrences and biotic interactions. Here, we present a new approach that uses Bayesian networks to improve predictions by modeling environmental co‐responses among species. For species from a European peat bog community, our approach consistently performs better than single‐species models and better than conventional multi‐species approaches that include the presence of nontarget species as additional independent variables in regression models. Our approach performs particularly well with rare species and when calibration data are limited. Furthermore, we identify a group of “predictor species” that are relatively common, insensitive to the presence of other species, and can be used to improve occurrence predictions of rare species. Predictor species are distinct from other categories of conservation surrogates such as umbrella or indicator species, which motivates focused data collection of predictor species to enhance conservation practices.     

Mediterranean island biodiversity and climate change: the last 10,000 years and the future

Mediterranean islands (MI) are hotspots of global biodiversity and lie in one of the most susceptible to climate change (CC) areas of the world; a big challenge for any conservation strategy. In fact, there is already increasing evidence for CC in the region and associated biological responses in MI ecosystems. These include phenological changes and upward elevation shifts of species and plant communities; although evidence is frequently contrasting for different taxa. Threats are also evident, mainly for endemic species from most taxonomic groups, while communities in mountain and coastal regions are likely to be affected most. For MI conservation under CC additional factors need to be considered: (i) their position at the crossroads of three continents; with which they share common environmental characteristics, (ii) their great variability in sizes and topography and (iii) their climatic differences; with a clear west-east basin divide. CC synergies with changing tourist aspiration and agricultural practices will, in the medium term, modify island landscapes and provide further challenges for biodiversity conservation. Such a combined impact from CC, land-use change, fragmentation of habitats and tourism is difficult to predict. Furthermore, the limited space on islands (especially habitat availability and climatic range limitations) imposes a barrier to species range expansion. Thus, conservation of MI biodiversity under CC requires: (i) future research to focus on improved climate predictions linked to improved understanding of ecological (climate-biotic) responses, incorporating lessons learnt from (island) biogeography, (ii) specific adaptation measures for spatial planning and improvement in regional institutional capacities.     

Enhancing pest control in annual crops by conservation of predatory Heteroptera

Conservation biological control (CBC) combines a diverse set of actions aiming to enhance pest regulation by the provision of pest natural enemies’ preservation in the crop environment. This is accomplished through appropriate implementation practices and the creation of infrastructures of non-crop vegetation. On most annual crops, omnivorous heteropteran predators comprise the main assemblage of native natural enemies. Their populations, when protected from pesticides, have shown a high potential in biological control. Aiming to promote their functioning in CBC, efforts targeted to modify the crop environment are focusing on the determination of their non-crop host plants that can support the predators’ persistence as well as the emigration of these predators to the nearby crops. Nonetheless, relatively few studies seek to collect essential and adequately verified data for the practical implementation of CBC approaches. In this review, the advances already developed are illustrated, the shortcomings are discussed and the future research needs are highlighted in an effort to intensify efforts for CBC developments on annual crops.     

Response of the two rare arable weed species Lithospermum arvense and Scandix pecten-veneris to climate change conditions

Rare weeds are currently under pressure due to intensifying arable management practices, and as a consequence of climate change, these practices will likely become even more intensive, together with a greater uniformity of land use. As a result, ecological stresses will increase for most species of rare weeds, in some cases leading to their further decline or even extinction. Moreover, climate change will alter the suitability of the environment for many plants, since average temperatures are predicted to increase and precipitation extremes to become more common. For most arable weed species it is unclear, whether the anticipated changes in environmental conditions are disadvantageous or beneficial. Little is known about specific biological responses of rare weeds to climate changes, and this study attempts to close some of these knowledge gaps. Here, the rare arable weed Lithospermum arvense and the endangered arable species Scandix pecten-veneris were investigated with regard to the effects of higher temperature and different crop densities on flowering time, shoot development, plant height, dry mass and seed production. Semi-field experiments were conducted with winter wheat crop for 3 years, involving 48 climate cages, in which every second was a variant of warmer temperature and contrasting crop density. We observed that S. pecten-veneris flowered earlier under warmer conditions and had fewer seeds and less biomass in the dense wheat crop compared to control conditions, while L. arvense grew taller, it produced fewer seeds in the high density crop. We suggest that such data concerning the biological responses of weeds can improve the precision of bioclimatic distribution models. Finally, we discuss strategies, such as relocation or non-intrusive management practices, for preventing further disappearances of rare arable weeds. Our results should be of considerable interest for the fields of plant ecology, biodiversity research and conservation.     

The UK Nest Record Scheme: its value for science and conservation

Capsule A review of its methodology, analytical procedures and uses.

Aims To provide a comprehensive review of the UK Nest Record Scheme (NRS), its methodology and value to science and conservation.

Methods We reviewed the history of the development and current methodology used in the analysis of NRS data in the scientific literature and unpublished documents and from our personal knowledge.

Results The British Trust for Ornithology's (BTO's) NRS is the largest, longest running and most highly computerized such scheme in the world. Advanced and efficient techniques of data gathering, data capture and analysis are used. It was founded in 1939 to provide information on the breeding biology of birds, but has since developed into a key component of the overall monitoring strategy for birds in the UK. A range of specialized analytical methods is available for NRS data and potential biases need careful treatment. More than 250 scientific publications have used NRS data to describe aspects of basic breeding biology and performance, to study the population dynamics of bird populations and to investigate the demographic causes of bird population declines in the UK.

Conclusions Extensive long-term monitoring schemes, such as the NRS, that collate large historical data sets will become increasingly valuable for monitoring the impact of environmental change. While aspects of the NRS, its recording methods, data capture and analysis can be developed further, the scheme will continue to advance our understanding of both the impacts of new environmental stresses in the UK and the effectiveness of new conservation measures in the wider countryside. This has been amply demonstrated by its use for exploring the impacts of global climate change on the UK's avifauna.     

Integrating Economic Costs and Biological Traits into Global Conservation Priorities for Carnivores

Background

Prioritization schemes usually highlight species-rich areas, where many species are at imminent risk of extinction. To be ecologically relevant these schemes should also include species biological traits into area-setting methods. Furthermore, in a world of limited funds for conservation, conservation action is constrained by land acquisition costs. Hence, including economic costs into conservation priorities can substantially improve their conservation cost-effectiveness.

Methodology/Principal Findings

We examined four global conservation scenarios for carnivores based on the joint mapping of economic costs and species biological traits. These scenarios identify the most cost-effective priority sets of ecoregions, indicating best investment opportunities for safeguarding every carnivore species, and also establish priority sets that can maximize species representation in areas harboring highly vulnerable species. We compared these results with a scenario that minimizes the total number of ecoregions required for conserving all species, irrespective of other factors. We found that cost-effective conservation investments should focus on 41 ecoregions highlighted in the scenario that consider simultaneously both ecoregion vulnerability and economic costs of land acquisition. Ecoregions included in priority sets under these criteria should yield best returns of investments since they harbor species with high extinction risk and have lower mean land cost.

Conclusions/Significance

Our study highlights ecoregions of particular importance for the conservation of the world''s carnivores defining global conservation priorities in analyses that encompass socioeconomic and life-history factors. We consider the identification of a comprehensive priority-set of areas as a first step towards an in-situ biodiversity maintenance strategy.     

Conserving and Enhancing Biological Control of Nematodes

Conservation biological control is the modification of the environment or existing practices to protect and enhance antagonistic organisms to reduce damage from pests. This approach to biological control has received insufficient attention compared with inundative applications of microbial antagonists to control nematodes. This review provides examples of how production practices can enhance or diminish biological control of plant-parasitic nematodes and other soilborne pests. Antagonists of nematodes can be enhanced by providing supplementary food sources such as occurs when organic amendments are applied to soil. However, some organic amendments (e.g., manures and plants containing allelopathic compounds) can also be detrimental to nematode antagonists. Plant species and genotype can strongly influence the outcome of biological control. For instance, the susceptibility of the plant to the nematode can determine the effectiveness of control; good hosts will require greater levels of suppression than poor hosts. Plant genotype can also influence the degree of rhizosphere colonization and antibiotic production by antagonists, as well the expression of induced resistance by plants. Production practices such as crop rotation, fallow periods, tillage, and pesticide applications can directly disrupt populations of antagonistic organisms. These practices can also indirectly affect antagonists by reducing their primary nematode host. One of the challenges of conservation biological control is that practices intended to protect or enhance suppression of nematodes may not be effective in all field sites because they are dependent on indigenous antagonists. Ultimately, indicators will need to be identified, such as the presence of particular antagonists, which can guide decisions on where it is practical to use conservation biological control. Antagonists can also be applied to field sites in conjunction with conservation practices to improve the consistency, efficacy, and duration of biological control. In future research, greater use should be made of bioassays that measure nematode suppression because changes in abundance of particular antagonists may not affect biological control of plant parasites.     

Inter-annual variability in the environmental performance of viticulture technical management routes—a case study in the Middle Loire Valley (France)

Purpose

Improving the environmental performances of viticulture practices is particularly complicated during unfavorable climatic conditions because of the need for fungal and other pest pressure and the variability of phytosanitary control methods available for winegrowers. However, winegrowers wish to improve the environmental performances of their practices regardless of climatic conditions. The objective of the study was to quantify the variability in environmental impacts due to climatic variations, and changes in viticulture practices induced by climatic variability.

Methods

Life cycle assessment was used to evaluate the environmental impacts of viticulture technical management routes (TMR) implemented on five plots in the Loire Valley for the Chenin Blanc grape variety. These TMRs are representative of the range of practices used in the region, including intensive conventional practices to moderate organic practices. The study covered two different years of production (2011 and 2013) under contrasting climatic conditions. The first year (2011) was hot and dry, which are favorable conditions for viticulture, while the second year (2013) was cold and humid, which are unfavorable conditions.

Results and discussion

During the unfavorable year, the number of phytosanitary treatments and soil maintenance interventions increased for most of the studied TMRs. This meant that the inter-annual variability in environmental impact was significant, depending on the type of TMR, with differences in impacts ranging from 19% to more than 40% between 2011 and 2013. Managing environmental impacts was found to be more difficult for the organic systems when climatic conditions are unfavorable (in 2013). The non-organic TMRs showed less variation in environmental impacts than the organic TMRs between the 2 years studied.

Conclusions

This study shows the importance of taking into account inter-annual variability in environmental assessments of viticulture systems. Indeed, winegrowers do not respond the same way to climate variability mainly with regard to plant protection and soil maintenance. Viticulture is very sensitive to inter-annual climate variations due to the parasitic pressure variability. The different production systems do not give to winegrowers the same possibilities for adapting practices to limit their impact on the environment.

     

Stabilizing Spatially-Structured Populations through Adaptive Limiter Control

Stabilizing the dynamics of complex, non-linear systems is a major concern across several scientific disciplines including ecology and conservation biology. Unfortunately, most methods proposed to reduce the fluctuations in chaotic systems are not applicable to real, biological populations. This is because such methods typically require detailed knowledge of system specific parameters and the ability to manipulate them in real time; conditions often not met by most real populations. Moreover, real populations are often noisy and extinction-prone, which can sometimes render such methods ineffective. Here, we investigate a control strategy, which works by perturbing the population size, and is robust to reasonable amounts of noise and extinction probability. This strategy, called the Adaptive Limiter Control (ALC), has been previously shown to increase constancy and persistence of laboratory populations and metapopulations of Drosophila melanogaster. Here, we present a detailed numerical investigation of the effects of ALC on the fluctuations and persistence of metapopulations. We show that at high migration rates, application of ALC does not require a priori information about the population growth rates. We also show that ALC can stabilize metapopulations even when applied to as low as one-tenth of the total number of subpopulations. Moreover, ALC is effective even when the subpopulations have high extinction rates: conditions under which another control algorithm had previously failed to attain stability. Importantly, ALC not only reduces the fluctuation in metapopulation sizes, but also the global extinction probability. Finally, the method is robust to moderate levels of noise in the dynamics and the carrying capacity of the environment. These results, coupled with our earlier empirical findings, establish ALC to be a strong candidate for stabilizing real biological metapopulations.     

Prospects for the Management of Invasive Alien Weeds Using Co-Evolved Fungal Pathogens: A Latin American Perspective

Invasive alien weeds pose a serious threat to the biodiversity of natural ecosystems and a significant constraint to agricultural production worldwide. The use of co-evolved natural enemies, a strategy referred to as classical biological control (CBC), has proven to be a potentially efficacious, cost-effective, and safe option for the management of alien weeds. An analysis of CBC of invasive weeds in Latin America is presented, which shows that only 5% of the worldwide releases of agents, overwhelmingly arthropod, have been in this region. Fungal pathogens are increasingly being considered in CBC programmes, and there are now 11 examples of Latin American fungi having been released as biocontrol agents in other regions of the world. In contrast, only three weed pathogens have been deliberately released in the region. Possible reasons for the paucity of CBC programmes in Latin America are presented, despite the presence of a significant number of alien weed species (60 are listed). An analysis of these weeds reveals that many of them could be amenable to control using natural enemies, including nine weed species for which CBC programmes have been successfully implemented elsewhere in the world. In addition, for many of these 60 species, a co-evolved and damaging mycobiota has already been recorded. The prospects for management of invasive alien weeds in Latin America, using co-evolved fungal pathogens, are assessed with particular reference to selected species from the genera Ambrosia, Broussonetia, Calotropis, Commelina, Cyperus, Dichrostachys, Echinochloa, Pittosporum, Rottboellia, Rubus, Sonchus and Ulex. This revised version was published online in July 2006 with corrections to the Cover Date.     

Building Taxon Substitution Guidelines on a Biological Control Foundation

When a species becomes extinct, its ecological functions are lost as well. Taxon substitution is a controversial approach to restoring such functions via introduction of non‐native species known to serve similar functions elsewhere. Due to the possibility of nontarget effects from such introductions, taxon substitution has been proposed and implemented in only a few systems, but these attempts have successfully restored functions. As a conservation tool, taxon substitution bears similarity to biological control, wherein species are also introduced for their ecological function with consideration of potential nontarget effects. To improve both the safety and efficacy of taxon substitution, regulatory bodies that currently issue guidelines for biological control can do the same for taxon substitution. Indeed, many biological control guidelines would apply well to taxon substitution. We examine the standard practices followed by biological control programs and propose corresponding taxon substitution guidelines. Integration of taxon substitution into the existing national and international environmental management conversation will improve the tool and has the potential to enhance conservation efforts across a wide diversity of systems if appropriate and stringent precautions are taken.     

Reprint of: Biological control of rice insect pests in China

Rice is one of the most important food crops in the world. China has the second largest area of the rice growing in the world and the highest yield of rice produced. Infestation by insect pests, especially rice planthoppers, stem borers and leaf folders, is always a serious challenge to rice production in China. Current methods for controlling insect pests in China mainly include good farming practices, biological control, breeding and growing resistant varieties, and the use of chemical insecticides. However, for farmers, the favorite method for insect pest control is still the application of chemical insecticide, which not only causes severe environmental pollution and the resurgence of herbivores but also reduces populations of the natural enemies of herbivores. To control insect pests safely, effectively and sustainably, strategies encouraging biological control are currently demanded. Here we review the progress that has been made in the development and implementation of biological controls for rice in China since the 1970s. Such progress includes the species identification of the natural enemies of rice insect pests, the characterization of their biology, and the integration of biological controls in integrated pest management. To develop effective ecological engineering programs whose aim is to implement conservation biological controls, further research, including the evaluation of the roles of plants in non-crop habitats in conservation biological controls, volatiles in enhancing efficiency of natural enemies and natural enemies in manipulating insect pests, and education to increase farmers’ knowledge of biological controls, is proposed.     

Provider Decisions to Treat Respiratory Illnesses with Antibiotics: Insights from a Randomized Controlled Trial

RationaleLower respiratory tract illness (LRTI) frequently causes adult hospitalization and antibiotic overuse. Procalcitonin (PCT) treatment algorithms have been used successfully in Europe to safely reduce antibiotic use for LRTI but have not been adopted in the United States. We recently performed a feasibility study for a randomized clinical trial (RCT) of PCT and viral testing to guide therapy for non-pneumonic LRTI.ObjectiveThe primary objective of the current study was to understand factors influencing PCT algorithm adherence during the RCT and evaluate factors influencing provider antibiotic prescribing practices for LRTI.ResultsDiagnosis of pneumonia on admission was the only variable significantly associated with non-adherence [7% (adherence) vs. 26% (nonadherence), p = 0.01]. Surveys confirmed possible infiltrate on chest radiograph as important for provider decisions, as were severity of illness, positive sputum culture, abnormal CBC and fever. However, age, patient expectations and medical-legal concerns were also at least somewhat important to prescribing practices. Physician agreement with the importance of viral and PCT testing increased from 42% to 64% (p = 0.007) and 49% to 74% (p = 0.001), respectively, after the study.ConclusionsOptimal algorithm adherence will be important for definitive PCT intervention trials in the US to determine if PCT guided algorithms result in better outcomes than reliance on traditional clinical variables. Factors influencing treatment decisions such as patient age, presence of fever, patient expectations and medical legal concerns may be amenable to education to improve PCT algorithm compliance for LRTI.     

Fallow management for steppe bird conservation: the impact of cultural practices on vegetation structure and food resources

The potential of fallow lands to favor farmland bird conservation is widely recognized. Since fallows provide key resources for birds within the agricultural matrix, such as nesting sites, shelter and forage, complete understanding of the effect of field-management strategies on vegetation structure and food is essential to fulfill bird requirements and improve habitat management. In this study we experimentally compare the most common field practices (ploughing, shredding, herbicide application and cover cropping) on fallow lands by assessing the resources they provide for birds in terms of vegetation structure and food resources (leaf and seed availability), as well as the economic costs of their implementation. Fallow management treatments are ranked for six target species in a lowland area of the north-eastern Iberian Peninsula, according to the available information on their requirements. The different agronomic practices offer various quantities and types of resources, highlighting the importance of fallow management in bird conservation. Shredding and early herbicide application (February) are estimated to be good practices for Little Bustard (Tetrax tetrax) and Calandra Lark (Melanocorypha calandra), providing both favorable habitat and foraging conditions, while being economical. Meanwhile, superficial tillage in spring is found to be optimum for the rest of the species tested, despite being among the poorest food providers. Alternating patches of the best treatments would improve the effectiveness of agri-environmental schemes by maximizing the harboring habitat for the endangered species.     

Imperfect detection and the determination of environmental flows for fish: challenges,implications and solutions

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Genomic and microarray approaches to coral reef conservation biology

New technologies based on DNA microarrays and comparative genomics hold great promise for providing the background biological information necessary for effective coral reef conservation and management. Microarray analysis has been used in a wide range of applications across the biological sciences, most frequently to examine simultaneous changes in the expression of large numbers of genes in response to experimental manipulation or environmental variation. Other applications of microarray methods include the assessment of divergence in gene sequences between species and the identification of fast-evolving genes. Arrays are presently available for only a limited range of species, but with appropriate controls they can be used for related species, thus avoiding the considerable costs associated with development of a system de novo. Arrays are in use or preparation to study stress responses, early development, and symbiosis in Acropora and Montastraea. Ongoing projects on several corals are making available large numbers of expressed gene sequences, enabling the identification of candidate genes for studies on gamete specificity, allorecognition and symbiont interactions. Over the next few years, microarray and comparative genomic approaches are likely to assume increasingly important and widespread use to study many aspects of the biology of coral reef organisms. Application of these genomic approaches to enhance our understanding of genetic and physiological correlates during stress, environmental disturbance and disease bears direct relevance to the conservation of coral reef ecosystems. S. Forêt and K.S. Kassahn contributed equally.