Explaining people's perceptions of invasive alien species: A conceptual framework

Educational Approaches Help Bridge Perception Gaps of Invasive Alien Species (Mikania micrantha) between Managers and Non-managers

Invasive alien species (IAS) significantly impact biodiversity, human health, and economies, and considerable resources are often used to manage their spread. Few studies have focused on the human perception of IAS management, and little is known about approaches to improve stakeholder perception. This study examined perception gaps between managers and non-managers of a notorious weed Mikania micrantha and the preference for educational approaches to bridge those gaps. Household questionnaires and key informant interviews were conducted in the China-Myanmar Border Region (China), and ordinal logistic regressions and Wilcoxon rank sum tests were used in statistical analyses. We found a high level of perception of M. micrantha among stakeholders, and a significant influence of socio-demographic factors including gender, educational level, ethnic group, and geographical location. Scores of the identification, damage, control measure, and manual treatment of M. micrantha were significantly higher for managers than those for non-managers, indicating that there were certain perception gaps between two stakeholder groups. Nine educational approaches were identified as being effective in improving stakeholder perception of IAS, of which training workshops were mostly preferred, followed by brochures (or leaflets) and other promotional materials. Additionally, we propose that well-designed and well-conducted educational approaches would benefit stakeholder perception of IAS, and that integration of IAS management into a comprehensive rural development scheme would improve its long-term performance in marginalized rural communities.

Lessons From a 10-yr Invasive Species Webinar Program: Emerald Ash Borer University

Information about invasive species needs to be spread rapidly across a wide geographic area following an invasion. However, in-person events can be time-consuming and costly for the participants, organizers, and presenters. Online programming like webinars can bridge this gap, but there is limited published data on how best to run these programs. We report on a 10-yr webinar program, Emerald Ash Borer University, and offer suggestions for improving their effectiveness as a communication tool. Webinar participants viewed the webinars positively and undertook recommended management actions. In addition, most of our survey respondents extended the reach of this program by widely sharing the information from the webinars. Posting the webinars on popular streaming platforms greatly extended their reach long after the live viewing event. Despite their longevity, viewers of recorded videos watched them differently than those viewing live events. We suggest modifying the format of future webinar presentations to accommodate these differences to improve information transfer.

Between approval and disapproval: Citizens’ views on the invasive tree Ailanthus altissima and its management

While cities are invasion hotspots, the view of urban residents on non-native species is critically understudied – an important knowledge gap since strategies on biological invasions could gain power by integrating human values, attitudes and perceptions. How citizens perceive the non-native tree Ailanthus altissima (tree of heaven) is unknown despite its abundance in many cities globally and its classification as invasive in many countries. In a quantitative survey with closed questions, we analysed (i) whether residents of Berlin, Germany knew the widespread species, (ii) how they perceived it in different urban situations, (iii) how they accepted different management strategies of it, and (iv) how the sociodemographic background of respondents predicted their preference and acceptability ratings.

In total, we surveyed 196 respondents. Most respondents recognized the tree in a photograph, but few provided its correct name. Citizens’ preferences differed significantly among four urban contexts in which the species was shown, with prevailing approval for trees as a component of designed green spaces and less pronounced preferences for wild-grown trees in other urban spaces. When respondents were asked to indicate how the tree should be managed (three options), we found the most support for removal in problematic cases (‘adaptive on-site’ strategy); some support was found for the ‘leave alone’ strategy and least support for the ‘complete removal’ management strategy. Practitioners with expertise in urban landscaping were more critical of Ailanthus than laypeople. Ordinal logistic regression analyses showed that respondents with a ‘close to nature’ behaviour and attitude had a more positive view on Ailanthus and expressed more support for ‘leave alone’ management. Results demonstrate the importance of citizens’ context dependent views about a widespread invasive species, spanning from approval to disapproval in different situations. We conclude that urban management strategies concerning Ailanthus would gain support from citizens when combining multiple approaches: (i) to control the species in case of realized negative impacts; (ii) to prevent the invasion of the species in areas of conservation concern; and (iii) to develop novel approaches of integrating wild Ailanthus trees into urban green spaces. These insights could support management measures that need to be established due to the EU-Regulation on Invasive Alien Species.

Lake Users’ Perceptions of Environmental Change: Ecosystem Services and Disservices Associated with Aquatic Plants

Lake Léman (Lake Geneva), Switzerland, is known to have undergone major environmental change over the last few decades, including changes in the abundance, distribution, and species composition of macrophytic plants (aquatic plants). In this study, questionnaires and key informant interviews were used to assess lake users’ perceptions of broad scale environmental change in the lake paying special attention tochanges in the abundance of aquatic plants and the perceived ecosystem services (ES) and ecosystem disservices (EDS) associated with them. In addition, we assessed whether users’ perceptions of aquatic plants had an impact on perceived management need. Most respondents (63%) perceived aquatic plant abundance to have increased over the last 10 years, primarily because of climate change. Aquatic plants were seen to benefit water quality through improved regulation and supporting services, and to provide important habitat and food for fauna. Most EDS associated with increased aquatic plant abundance were categorized as cultural or economic. User perceptions of the ES and EDS associated with aquatic plants affected support for management (60% of respondents supported some form of management), and such information is important for informing environmental decision making.

Moving from Latent to Manifest Problem: Trajectories Across Scientific and Public Salience of Invasive Alien Species

Who worries first about an invasive alien species: scientists or the general public, or do both become concerned simultaneously? Taking thirteen invasive alien species in the Netherlands, this article reconstructs the development of their public and scientific salience: the attention they attracted and the knowledge about them. Salience was assessed from the number of publications from 1997 onwards in the LexisNexis newspaper database and Scopus scientific database. Three trajectories were derived for a species to move from being a latent problem with low salience toward a manifest status with high public and scientific salience. In the most common trajectory, scientific salience increased first, followed by an increase in public salience. We probed the merit of this concept of trajectories by examining the action undertaken for a representative species of the trajectories. We assigned each of these three species a code for inertia and inaction based on the content of a hundred newspaper articles and all available government documents. Knowing the scientific and public salience of these species clarifies why the actions to deal with them differed even though from an ecological perspective they warranted similar attention. The typology of public and scientific salience and the problem trajectories developed in this article together offer a structured approach for understanding an invasive alien species and provide pointers for engaging a community in managing that species.

Functional diversity changes in native and alien urban flora over three centuries

Alien species in urban areas have a large effect on overall species diversity. A suitable metric of flora’s response to environmental change is functional diversity (FD) that refers to the multivariate space of species’ trait compositions, reflecting their ecological niches. We studied how FD changed over 320 years of urbanization in the city of Halle (Saale), Germany. Selected functional traits (related to stress-tolerance, reproduction, competitiveness and phenology) were examined for the difference in FD between native and alien plant species, the latter specifically for archaeophytes, neophytes and invasive species. Functional diversity for each trait was calculated using Rao’s Q index followed by a linear model to test for changes in Rao’s Q over time between the groups. Over the 320 years, overall FD remained constant despite species turnover, but FD significantly increased for neophytes and invasive species compared to native species. Plant height was the only trait showing increase in FD as main effect, while for the other traits examined FD decreased over time. Considering invasive species separately, the majority of traits exhibit a significant increase in FD except for seed mass where it decreased. Finally, FD of multiple functional traits combined decreased over time. This can be due to homogenization of functional trait between native and alien species, as a consequence of habitats becoming more similar and subsequent habitat filtering. Our results demonstrate that during the last three centuries, urbanization influenced plant FD in various ways and may contribute to future uniformity of urban floras and greater invasiveness.

Biological invasions in brazilian environmental science courses: do we need new approaches?

The increasing destruction of natural environments worldwide favored more and more alien species’ dispersal, distancing people from nature and consequently from native species. We investigated undergrad students’ perception about alien and native Brazilian species evaluating classes of the first (freshmen) and last semesters (seniors) of four courses in environmental sciences in three institutions and assessed these students’ knowledge level in different aspects related to native and alien species. The 509 interviewees were able to identify Brazilian native species better than alien species. They also produced better identifications among taxonomic groups of mammals (either alien or native), native birds, and exotic fish compared to invertebrate species. Most students did not consider themselves well informed about the topic. We found an association between the courses/semesters attended and the level of knowledge of the students. Thus, we concluded that, on the one hand, the students demonstrated relevant knowledge about the native species but, on the other, presented deficiencies in invasive alien species’ knowledge. Therefore, we suggest the revision/restructuring of how the biological invasions theme is covered in the academic curricula of undergraduate courses in the environmental area.

From the Andes to the Apennines: Rise and Fall of a Free-Ranging Population of Feral Llamas

Simple Summary

Domestic mammals may become invasive alien species when introduced within natural environments and when they establish reproductive populations. One of the most common pathways of species introduction is represented by intentional or accidental escapes from confined environments, including zoos, farms and enclosures. A feral population of llama Lama glama has been present in Central Italy since 2016 after escaping from a zoological garden. In 2020, only three individuals were confirmed to be still present within a 40-hectare area, following a field survey. We carried out questionnaires with the resident human population to determine the local perception and the acceptance of two possible management actions, i.e., direct killing and surgical sterilization. Llamas are quite docile domestic animals, thus local perception was, in general, very positive and also linked to the exotic origin of the species, making llamas a welcome observation and a pleasant surprise. The observed decline of this population may be due to predation by wolves and poaching, together with the lack of suitability of natural environment, which may have prevented llamas establishing an invasive population. In this context, however, individual removal action should be conducted before the population shows a demographic rebound.

Abstract

Since 2016, a feral population of llama Lama glama has been present in Central Italy after escaping from a zoological garden and starting to reproduce. We updated demographic status and distribution of this population and investigated societal perception towards the llama presence and management in the area through a standard questionnaire. Field data were collected through direct (transects traveled by car and on foot) and indirect (newspapers, social networks and online platforms) research. The feral population appears to be declining. In July 2020, the population was represented by three individuals (one male and two females), identified also through photoidentification, most likely located within a 40-hectare area. The majority of citizens are aware of the presence of feral llamas and show a positive attitude toward them and a negative one toward management actions. The case of feral llamas in Italy is an evident example of unsafe management of a species which should have kept in a zoo and which, once set free, was able to catalyze the attention of the general public. The decline of this population limits the need of drastic management actions that, given the appreciation expressed by people and press toward these animals, would have been at risk of conflict with the public opinion. Removal action should be rapidly taken, i.e., before any demographic rebound and before the population becomes a stable feature of the local landscape.

The role of citizen science in management of invasive avian species: What people think, know, and do

In North America, nest site competition from invasive cavity-nesting birds can limit the opportunities for successful nesting by native birds. Managing invasive species is costly and complex, requiring input from biologists, decision makers, and the public. An informed and engaged public can play an important role in mitigating the negative effects of invasive avian species. However, little is known regarding the publics' knowledge, attitudes, and behaviors toward non-native bird species. We examined the association between participating in a citizen science project and enjoyment, knowledge, and management of two non-native avian species in North America: European starlings (Sturnus vulgaris) and house sparrows (Passer domesticus). We administered a pre and post survey to 947 people who monitor nest boxes in the United States and Canada, 30% of whom were also reporting their observations to NestWatch, a citizen science project focused on nesting birds. We found that NestWatch participants were more likely to have negative views of non-native species, score higher on bird identification tasks, and manage for invasive species than non-participants. The most important predictor for undertaking management activities was respondents' perceptions of whether they believed non-native birds to be a problem at the continental scale, underscoring the important role of individual factors such as perception. Our study also highlights the important role citizen science may play in shaping attitudes and behaviors and increasing knowledge. We propose a conceptual model describing the mechanisms by which citizen science can be leveraged for management of invasive species.

Beekeepers perception of risks affecting colony loss: A pilot survey

Understanding amateur beekeepers' perception of risks affecting bee health and mortality is essential to analyse the reasons for adopting or rejecting good management practices. A perception survey on how beekeepers perceive and manage factors related to climate change, Varroa infestation, management practices, and pesticide exposure was designed and launched online. This unpreceded sociological survey involved 355 beekeepers spread all over Belgium. A two-sample t test with unequal variances comparing beekeepers with colony loss rates below or exceeding the acceptable level, that is <10% and ≥10%, indicates that beekeepers (N = 213) with colony loss rates <10% generally have greater average levels of perceived risks and the benefits of action that lead to increased motivation to act in better ways. The results of this survey highlight the importance of looking beyond socio-economic determinants in any risk mitigation strategy associated with bee mortality when dealing with amateur beekeepers.

What drives private landowner decisions? Exploring non-native grass management in the eastern Great Plains

Non-native grasses used as forage for domestic livestock can negatively impact ecosystem services provided by grasslands. In the U.S., most grazed grasslands are privately owned so the introduction and reduction of non-native grasses are both driven by landowner behavior. Yet, the social factors that shape non-native grass management are rarely explored. To address this knowledge gap, we evaluated how decisions to reduce these grasses through practices such as herbicide application, prescribed fire, and physical removal are influenced by attitudes, norms, and perceived ability. We administered a mixed mode (mailback and online) survey in 2017 to landowners in the eastern Great Plains of the U.S., in a region where cattle production remains the predominant land-use. Using structural equation modeling with parceling, we tested hypotheses related to management decisions derived from a model integrating two theories - the Theory of Planned Behavior and the Norm Activation Model. In this analysis, we identified perceived ability (i.e., access to time, skills, or other necessary resources) as a barrier to adoption for landowners who were already willing to manage non-native grasses. Positive attitudes toward management and increased social norm pressures were both associated with increased sentiments of moral responsibility to reduce non-native grasses. These personal norms, together with attitudes, positively influenced willingness to control non-native grasses. Further, we observed that social norms related to expectations of neighbors had more influence on personal norms than the social norms from natural resource agencies. The power of norms to explain individual management decisions suggests that landowners could be engaged in landscape-scale initiatives by leveraging moral responsibility and influential social groups.

Invasive raccoon management systems and challenges in regions with active control

BACKGROUND

The raccoon (Procyon lotor) is an invasive, non-native species in Japan. Throughout the country, it causes significant agricultural damage and negatively affects native biodiversity. Most of the responsibility for raccoon management lies with local government, and there are still many challenges to be overcome. Although raccoon populations have not been eradicated, intensive control campaigns such as focus on the early stages of invasion have controlled raccoons in some regions. To improve the national management of raccoons, we conducted a survey on raccoon management systems in local government departments considered to solve the challenges recognized in many areas. During 2014 and 2015, we surveyed three different municipal departments about raccoon management measures. The semi-structured interview survey covered two topics: (1) the situation leading up to the current management system; (2) the current management system.

RESULTS

Our results describe the scope and methods used in raccoon management. The government staff managed raccoons using monitoring, employing a variety of methods, a range of budgets, and various role divisions. The management practices are similar in that they share a sense of taking precautions, collaborating with stakeholders, understanding that adequate methods must be used, and obtaining support from experts.

CONCLUSIONS

Our case studies reveal the challenges in raccoon management faced by local government officers in regions with active control. The management systems and methods that we surveyed seemed to be effective in solving problems in both developed and undeveloped areas.

People's Knowledge and Risk Perceptions of Invasive Plants in Metro Vancouver, British Columbia, Canada

Effective management of invasive plants conserves biodiversity values, reduces economic costs, and minimizes negative impacts on human health. Fostering people's awareness of invasive plants is one of the most cost-effective approaches in preventing the spread and introduction of invasive plants. Therefore, this study aims to understand (1) people's knowledge and risk perceptions, (2) associations between risk perceptions and demographics, and (3) people's willingness to support current management strategies in the Metro Vancouver region, British Columbia, Canada. An online survey was carried out and received 356 responses across the region. We found that people's knowledge and risk perceptions of invasive plants were ecologically oriented. Older respondents perceived higher risks of invasive plants. Among respondents of the same age, annual income higher than $50,000 was associated with higher levels of risk perception. Respondents who had professional and/or recreational group memberships perceived higher economic risks. Respondents highly supported activities that they could take part in directly, such as community invasive pulls and native species planting. Overall, our findings aid managers in allocating appropriate funding or tailoring outreach efforts to different aspects of invasive plants as well as groups/communities where people's knowledge and risk perceptions of invasive plants are low.

The importance of assessing positive and beneficial impacts of alien species

Extensive literature is available on the diversity and magnitude of impacts that alien species cause on recipient systems. Alien species may decrease or increase attributes of ecosystems (e.g. total biomass or species diversity), thus causing negative and positive environmental impacts. Alien species may also negatively or positively impact attributes linked to local human communities (e.g. the number of people involved in a given activity). Ethical and societal values contribute to define these environmental and socio-economic impacts as deleterious or beneficial. Whilst most of the literature focuses on the deleterious effects of alien taxa, some recognise their beneficial impacts on ecosystems and human activities. Impact assessment frameworks show a similar tendency to evaluate mainly deleterious impacts: only relatively few, and not widely applied, frameworks incorporate the beneficial impacts of alien species. Here, we provide a summary of the frameworks assessing beneficial impacts and briefly discuss why they might have been less frequently cited and applied than frameworks assessing exclusively deleterious impacts. Then, we review arguments that invoke a greater consideration of positive and beneficial impacts caused by alien species across the invasion science literature. We collate and describe arguments from a set of 47 papers, grouping them in two categories (value-free and value-laden), which span from a theoretical, basic science perspective to an applied science perspective. We also provide example cases associated with each argument. We advocate that the development of transparent and evidence-based frameworks assessing positive and beneficial impacts might advance our scientific understanding of impact dynamics and better inform management and prioritisation decisions. We also advise that this development should be achieved by recognising the underlying ethical and societal values of the frameworks and their intrinsic limitations. The evaluation of positive and beneficial impacts through impact assessment frameworks should not be seen as an attempt to outweigh or to discount deleterious impacts of alien taxa but rather as an opportunity to provide additional information for scientists, managers and policymakers.

Beliefs and Attitudes of Residents in Queensland, Australia, about Managing Dog and Cat Impacts on Native Wildlife

Many humans have created close relationships with wildlife and companion species. Notwithstanding that companion species were at some point themselves wild, some wild (i.e., feral) and domesticated (owned) dogs and cats now have significant impacts on wildlife. Many strategies exist to control the impact of dogs and cats on wildlife, but the successful implementation of management initiatives is tied to public opinions and the degree of acceptability of these measures. This paper reports the findings of a survey assessing the beliefs of residents in Queensland, Australia, about dog and cat impacts on wildlife, and their attitudes towards various strategies and options for controlling wild (i.e., feral) and domesticated (owned) dogs and cats. The responses of 590 participants were analysed. Our respondents collectively grouped strategies into those that directly cause wild dog and cat deaths and those that allow wild dogs and cats to live a 'natural' life, which is a variation on past research where respondents grouped strategies into lethal and non-lethal methods. Community acceptability of strategies that directly cause wild dog and cat deaths (each assessed using five-category Likert scores) was lower amongst females and respondents aged 34 years or less. Gender expectations in most places and cultures still predominately suggest that women are more 'caring', supportive of animal welfare, and perhaps cognizant that wild dogs and cats are also sentient creatures and appreciate the problematic tension between controlling wild and companion species. Age-related differences may reflect the changing social values of communities at different points in time. There was high support for regulations that enforce responsible pet ownership but not for the importance of pet-free suburbs, which the majority of respondents considered unimportant. These important variations in beliefs and attitudes require careful management within each community for the success of any program to control wild dogs or cats.

Early warning systems in biosecurity; translating risk into action in predictive systems for invasive alien species

Invasive alien species (IAS) are one of the most severe threats to biodiversity and are the subject of varying degrees of surveillance activity. Predictive early warning systems (EWS), incorporating automated surveillance of relevant dataflows, warning generation and dissemination to decision makers are a key target for developing effective management around IAS, alongside more conventional early detection and horizon scanning technologies. Sophisticated modelling frameworks including the definition of the ‘risky’ species pool, and pathway analysis at the macro and micro-scale are increasingly available to support decision making and to help prioritise risks from different regions and/or taxa. The main challenges in constructing such frameworks, to be applied to border inspections, are (i) the lack of standardisation and integration of the associated complex digital data environments and (ii) effective integration into the decision making process, ensuring that risk information is disseminated in an actionable way to frontline surveillance staff and other decision makers. To truly achieve early warning in biosecurity requires close collaboration between developers and end-users to ensure that generated warnings are duly considered by decision makers, reflect best practice, scientific understanding and the working environment facing frontline actors. Progress towards this goal will rely on openness and mutual understanding of the role of EWS in IAS risk management, as much as on developments in the underlying technologies for surveillance and modelling procedures.

Societal attention toward extinction threats: a comparison between climate change and biological invasions

Public attention and interest in the fate of endangered species is a crucial prerequisite for effective conservation programs. Societal awareness and values will largely determine whether conservation initiatives receive necessary support and lead to adequate policy change. Using text data mining, we assessed general public attention in France, Germany and the United Kingdom toward climate change and biological invasions in relation to endangered amphibian, reptile, bird and mammal species. Our analysis revealed that public attention patterns differed among species groups and countries but was globally higher for climate change than for biological invasions. Both threats received better recognition in threatened than in non-threatened species, as well as in native species than in species from other countries and regions. We conclude that more efficient communication regarding the threat from biological invasions should be developed, and that conservation practitioners should take advantage of the existing attention toward climate change.

Perceptions of alien plants and animals and acceptance of control methods among different societal groups

Biological invasions are a widespread phenomenon and cause substantial impacts on the natural environment and human livelihoods. Thus, the European Union (EU) recently adopted Regulation No 1143/2014 to limit the negative impacts of invasive alien species (IAS). For implementing IAS management and policies, public support is highly and increasingly important, especially when it comes to charismatic species and lethal methods. Recognising the importance of the interaction of public perception with acceptance of IAS management methods, we used an online survey targeting three different stakeholder groups in Austria to evaluate potential differences in perception of IAS and management methods.

In total, we received 239 completed responses: 20 nature users (farmers, hunters), 91 nature experts (conservationists, biologists) and 128 from the general public. Participants were more likely to accept lethal management methods when it was an IAS. Nature experts’ acceptance of IAS management methods was rather similar to those of nature users, while the general public preferred non-lethal methods. Chemical lethal methods (herbicides, poison pellets) received low rates of acceptance throughout all stakeholder groups, although nature users were more open to accept such methods for plants. Most respondents (&gt; 50%) were not aware of the role of the EU in IAS topics nor did they know of the existence of the EUIAS regulation 1143/2014. However, more than 75% of respondents agreed that IAS measures and regulations should be implemented at EU level.

This study shows that knowledge about native versus invasive alien status has an influence on the acceptance of management methods. Nature users may have higher levels of acceptance of lethal methods because they are economically dependent on extracting resources from nature. Invasive alien species regulations on EU level are generally acceptable, but there is low awareness for actions already undertaken EU.

Using online questionnaires to assess marine bio-invasions: A demonstration with recreational fishers and the Atlantic blue crab Callinectes sapidus (Rathbun, 1986) along three Mediterranean countries

Marine bioinvasions require integrating monitoring tools with other complementary strategies. In this study, we collected information about the invasive alien crab Callinectes sapidus in Italy, Croatia and Montenegro, by means of online questionnaires administered to recreational fishers (n = 797). Our records matched the current distribution of the species: C. sapidus resulted far more common in the Adriatic/Ionian than in the Tyrrhenian/Ligurian sector. Most respondents rated the species as 'occasional' or 'rare'. Moreover, the more C. sapidus was considered to be abundant, the more fishers tended to perceive it as a negative disturbance over fisheries and the environment. Our findings suggest that C. sapidus is more common than previously thought in most of the study area, and it could have reached the levels of a true invasions in the south-eastern Adriatic Sea. This experience demonstrates that online questionnaires can be appropriate tools to effectively engage stakeholders in alien species monitoring.

Communicating with the Public about Emerald Ash Borer: Militaristic and Fatalistic Framings in the News Media

Invasive species can spread to new landscapes through various anthropogenic factors and negatively impact urban ecosystems, societies, and economies. Public awareness is considered central to mitigating the spread of invasive species. News media contributes to awareness although it is unclear what messages are being communicated. We incorporated Frame Theory to investigate newspapers’ coverage of the emerald ash borer (EAB; Agrilus planipennis Fairmaire (Coleoptera: Buprestidae)), which has killed millions of ash trees in the continental United States. We conducted a content analysis of 924 news articles published between 2002 and 2017 to examine language framing (how a phenomenon like invasive species is constructed and communicated), information sources, management methods, recommended actions for the public and whether this communication changed overtime. Seventy-seven percent of articles used language evocative of distinctive risk framings, with the majority of these using negative attribute frames like invasion-militaristic and/or fatalistic language to describe EAB management. Few discussed positive impacts like galvanizing public support. Most articles used expert sources, primarily government agents. We recommend that public communications regarding invasive species be cautious about language evoking militarism and fatalism. Furthermore, invasive species communication requires a broader diversity and representation of voices because invasive species management requires community effort.

A protective nesting association with native species counteracts biotic resistance for the spread of an invasive parakeet from urban into rural habitats

Background

Non-native species are often introduced in cities, where they take advantage of microclimatic conditions, resources provided by humans, and competitor/predator release to establish and proliferate. However, native communities in the surrounding rural or natural areas usually halt their spread through biotic resistance, mainly via top-down regulative processes (predation pressure). Here, we show an unusual commensal interaction between exotic and native bird species that favours the spread of the former from urban to rural habitats.

Results

We show how Monk parakeets Myiopsitta monachus, an invasive species often introduced in cities worldwide, associated for breeding with a much larger, native species (the white stork Ciconia ciconia) to reduce predation risk in central Spain, thus allowing their colonization of rural areas. Parakeets selected stork nests close to conspecifics and where breeding raptors were less abundant. Parakeets always flushed when raptors approached their nests when breeding alone, but stayed at their nests when breeding in association with storks. Moreover, when storks abandoned a nest, parakeets abandoned it in the following year, suggesting that storks actually confer protection against predators.

Conclusions

Our results show how a protective-nesting association between invasive and native species can counteract biotic resistance to allow the spread of an invasive species across non-urban habitats, where they may become crop pests. Monk parakeet populations are now growing exponentially in several cities in several Mediterranean countries, where they coexist with white storks. Therefore, management plans should consider this risk of spread into rural areas and favour native predators as potential biological controllers.

Assessment of Useful Alien Plant Species Cultivated and Managed in Rural Home Gardens of Limpopo Province, South Africa

Several communities in developing countries derive substantial part of their livelihood needs from alien plants cultivated and managed in home gardens. The aim of this study was to assess useful alien plant species cultivated and managed in home gardens of Limpopo province in South Africa. Semistructured interviews, personal observation, and guided walks with 300 participants between January 2015 and December 2016 were employed to obtain data on names of alien plants cultivated in home gardens and their use categories. A total of 101 plant species belonging to 44 families were recorded from the study area. More than half of the species (66.3%) belonged to 14 families, Fabaceae, Asteraceae, Rosaceae, Solanaceae, Lamiaceae, Anacardiaceae, Poaceae, Amaranthaceae, Apocynaceae, Brassicaceae, Cactaceae, Euphorbiaceae, Moraceae, and Myrtaceae. Twenty-six use categories of alien plants were identified in this study with the majority of species (75.2%) used for medicinal purposes, followed by ornamental (33.7%), edible fruits (24.8%), spices (16.8%), vegetables (16.8%), shade (11.9%), beverages (10.9%), construction materials (8.9%), firewood (7.9%), and hedge (7.9%). These findings corroborate the existing body of knowledge emphasizing the importance of plants grown and managed in home gardens to the livelihood needs of local communities.

Science communication is needed to inform risk perception and action of stakeholders

Stakeholders are critical environmental managers in human-dominated landscapes. In some contexts, stakeholders can be forced to personally act following their own observations and risk perception instead of science recommendation. In particular, biological invasions need rapid control actions to reduce potential socio-ecological impacts, while science-based risk assessments are rather complex and time-delayed. Although they can lead to important detrimental effects on biodiversity, potential time-delayed disconnections between stakeholders' action and science recommendations are rarely studied. Using the case study of western European beekeepers controlling the invasive Asian hornet Vespa velutina nigrithorax for its suspected impact on honey bee colonies, we analysed mechanisms underlying personal actions of stakeholders and how they evolved in science disconnection. Personal actions of stakeholders were causal-effect linked with their risk observation but disconnected to time-delayed science predictions and recommendations. Unfortunately, these science-disconnected actions also led to dramatic impacts on numerous species of the local entomofauna. These results highlight the need to improve mutual risk communication between science and action in the early-stages of management plans to improve the sustainably of stakeholders' practices.

Diverse views among scientists on non-native species

Conservation scientists have traditionally viewed non-native species (NNS) as potential threats to native biodiversity. Here, we question whether alternative views of NNS exist in the scientific community that stand in contrast to the dominant narrative that emerges from the literature. We asked researchers from the biological, social, and environmental sciences to participate in an anonymous poll regarding the perceived values and threats of NNS. Some 314 individuals responded, approximately half of whom were biologists and half were social or environmental scientists. We grouped responses into three statistical clusters defined by shared responses. We then analyzed the correlation of responses to individual questions and membership of clusters with predictor variables age, gender, and field of work. Overall, a majority of respondents in our sample supported statements that the species-component of biodiversity should include all species (55%) or some types of non-native species (an additional 32%), which contrasts with the manner in which major biodiversity assessments and indicators are constructed. A majority of respondents in our sample (65%) also supported that measurement of the impact of invasive species should be based on the net biological, social, and economic effects, which also represents a marked departure from current methods that focus only on the adverse effects of a subset of NNS considered as invasive. Field of work and age were correlated with clusters and numerous individual responses. For example, biologists were three-times more likely than non-biologists to support a definition of species richness that included only native species. Two clusters (Cluster 1 and Cluster 3), mainly composed of non-biologists and biologists, respectively, differed in their support for statements that NNS would provide useful ecosystem services in the future (66% and 40%, respectively). Thus, a key result of this study is that a variety of normative stances regarding NNS is present within the scientific community. Current international indicators of progress (e.g., Aichi Targets) capture only a “nativist” set of values, which, if our sample is representative of the scientific community, appears to be a minority view. Therefore, we argue that indicators should be modified to integrate the diversity of views that exist within the scientific community.

Effective governance for management of invasive alien plants: evidence from the perspective of forest and wildlife officers in Sri Lanka

Invasive alien plants (IAPs) are a significant cause of socio-ecological change in Sri Lanka. Many studies have focused on the ecological dimensions of this problem, but few have addressed sociological factors such as the knowledge and perceptions of individuals and groups tasked with addressing IAPs. This study investigates how IAP issues are understood and perceived by professional forest and wildlife officers in Sri Lanka. The data analyzed were gathered using a questionnaire that covered three themes: the respondents' ability to identify IAPs, the impacts of IAPs and the threats they pose, and knowledge regarding control and mitigation. The questionnaire was completed by 186 field officers, and the resulting descriptive statistics and a probit regression analysis were used to analyze the data. The results show that almost all of the participating forest and wildlife officers were aware of the problems associated with IAPs but more than 75% of them lacked an accurate understanding of scientific means for controlling them and control policies established by the government of Sri Lanka. Generally, wildlife officers had a better understanding than forest officers. In addition, the analysis shows that officers' knowledge and perceptions of IAPs were positively correlated with their level of education and position within the organization. The analysis points to several recommendations for Sri Lankan officials when designing and implementing comprehensive policies and professional programs, particularly for lower-level field officers.

The pest-management attitude (PMA) scale: a unidimensional and versatile assessment tool

Abstract ContextPest species are a widespread environmental and biodiversity threat and understanding people’s attitudes towards managing pests is critical for nature conservation. Attitudes towards pest species and their management are often contextually dependent on the species and location, and no domain-free measure is currently available. This prevents straightforward comparisons of studies and generalisation of attitudes towards pest species globally. AimUndertake initial psychometric tests of a unidimensional pest-management attitude (PMA) scale in three community samples from the two largest cities of New Zealand. The PMA scale comprises statements intentionally absent of specific reference to pest species or pest-management methods, and avoids terminology that has the potential to become outdated, as a result of evolving management methods and technology or the emergence of new pests. This broad focus aims to enable the ongoing use of the scale, within differing geographical contexts. MethodTwo studies tested the psychometric properties of the PMA scale. Tests comprise assessing the scales dimensionality through exploratory and confirmatory factor analysis, and measurement equivalence across samples. Internal consistency was tested through Cronbach’s α, and demographic and context-specific measures were used to validate the scale using correlation measures. ResultsExploratory and confirmatory factor analyses confirmed the nine-item, one-factor model of the PMA scale in Study 1 (n=1190). Measurement and structural invariance of the one-factor model was confirmed across two distinct samples in Study 2 (n=739 and 705). Internal consistency (Cronbach’s alphas=0.73 to 0.81) and criterion-related validity of the PMA scale was supported in both studies, with greater PMA scores being associated with membership of a conservation or environmental organisation, active participation in conservation over the past 12 months, active actions for pest control, and not owning a pet. ConclusionsResults demonstrated high construct and criterion validity of the PMA scale, which might have powerful global utility as a context-independent measure of attitudes to pest species and their management. ImplicationsThrough generalising the social components of pest management, regardless of target species or method, there is potential to unify global studies in pest management.

Human adaptation to invasive species: A conceptual framework based on a case study metasynthesis

Species invasions are a major driver of ecological change, are very difficult to control or reverse, and will increase with climate change and global trade. Invasion sciences consider how species in invaded environments adapt, but neither scientists nor policy makers consider human adaptation to invasive species and how this affects ecosystems and well-being. To address this, a framework conceptualising autochthonous human adaptation to invasions was developed based on the Human Adaptation to Biodiversity Change framework and a case study metasynthesis. Results show that adaptation occurs within different spheres of human activity and organisation at different social-ecological scales; responses have feedbacks within and across these spheres. Adaptation to invasives and other drivers is a set of highly contextual, complex, non-linear responses that make up pathways pursued over time. Most invasive species management and adaptation occurs 'from below,' and policies and planned control efforts should support autochthonous adaptation, rather than undermining it.

You Can’t See the Woods for the Trees: Invasive Acer negundo L. in Urban Riparian Forests Harms Biodiversity and Limits Recreation Activity

Public access to high quality green environments has become a key issue for city managers and a matter of environmental justice. Urban pressures on ecosystem remnants may act to favor the expansion of some invasive species in cities. Whilst the negative impacts of invasive species on ecosystem function is well documented, little is known about how invasive species influence the use of green space by people. Here, we examined one of the few remnants of urban riparian forests in Europe, the Vistula river valley in Warsaw, which has recently become an attractive recreation site. Despite their high ecological value, the poplar and willow forests have been increasingly taken over by the invasive tree species Acer negundo. We examined the status of the invasion process and the relationship between recreational ecosystem services and the characteristics of the tree stands—tree species, tree density, and age and NDVI values. We found the willow forest to be more susceptible to invasion by A. negundo than the poplar forest, which was revealed in significantly higher share of the maple individuals and their greater volume per unit area. Ash-leaved maples also prevailed in numbers in younger stands (<10 years) than in older ones. The presence of A. negundo affected biodiversity, resulting in decreased undergrowth density and biodiversity expressed in number of species. The use intensity by the public, assessed on the basis of soil compaction of existing informal tracks, as revealed by GLM analysis, was related to volume of invasive maple and distance from the main track. This study highlights the need to integrate invasive species management into green infrastructure planning and management.

Are the ecological effects of the "worst" marine invasive species linked with scientific and media attention?

Non-native species are a major driver of environmental change. In this study we assessed the ecological impact of the “worst” non-native species and the associated scientific and media publications through time to understand what influences interest in these species. Ecological effect was based on a qualitative assessment reported in research publications and additional searches of the scientific and media attention were conducted to determine published articles and assess attention. We did not detect a relationship between the number of publications for a non-native species and the magnitude of the ecological effects of that species or the number of citations. Media coverage on non-native species was low, only evident for less than 50% of the non-native species assessed. Media coverage was initially related to the number of scientific publications, but was short-lived. In contrast, the attention to individual non-native species in the scientific literature was sustained through time and often continued to increase over time. Time between detection of the non-native species and the scientific/media attention were reduced with each successive introduction to a new geographic location. Tracking publications on non-native species indicated that media attention does seem to be associated with the production of scientific research while scientific attention was not related to the magnitude of the ecological effects.

Research on the social perception of invasive species: a systematic literature review

We conducted a systematic literature review of the current state of research on the social perceptions of invasive species, aiming to provide guidance towards transdisciplinary research and participatory decision making. In order to detect patterns regarding publication trends and factors determining social perceptions of invasive species, we applied qualitative content as well as quantitative data analysis. By applying content analysis, we identified five main categories of influence on the perception of invasive species: ecological conditions, social conditions, values and beliefs, impacts, and benefits. The disciplinary focus of the research was predominantly interdisciplinary, followed by a social sciences approach. Our review revealed a disproportionate use of quantitative methods in research on social perceptions of invasive species, yet quantitative methods were less likely to identify benefits as factors determining the perception of invasive species. However, without the understanding of perceived benefits, researchers and managers lack the socio-cultural context these species are embedded in. Our review also revealed the geographical, methodological and taxonomic bias of research on perceptions of invasive species. The majority of studies focused on the local public, whereas fewer than half of the studies focused on decision-makers. Furthermore, our results showed differences in the social perceptions of invasive species among different stakeholder groups. Consensus over the definition and terminology of invasive species was lacking whereas differences in terminology were clearly value-laden. In order to foster sustainable management of invasive species, research on social perceptions should focus on a transdisciplinary and transparent discourse about the inherent values of invasion science.

Predictors of Participation in Invasive Species Control Activities Depend on Prior Experience with the Species

The increasing worldwide spread of non-native species is both a component and a consequence of environmental change, and islands are especially vulnerable to negative effects. Efforts to control non-native species often include public education intended to promote behaviors designed to reduce or reverse their spread. To inform the use of information strategies to control the invasive, non-native frog Eleutherodactylus coqui in Hawaii, USA, we surveyed over 700 property owners about their attitudes and behaviors regarding the species. Included were residents of the island of Hawaii, where the species is common and management emphasizes prevention of further spread, and three other islands where the species is largely absent and management emphasizes detection and eradication. Where frogs are present, 61% of respondents reported taking actions to reduce their population, typically clearing vegetation or hand-capturing individual frogs. For these individuals, intentions to engage in future control activities were not significantly related to reports of past behavior. Intentions to participate in future control efforts on the island of Hawaii were best predicted by attitudes toward practices. On the other islands, behavioral intentions were best predicted by subjective norms (i.e., beliefs about others' expectations that they should manage frogs). Thus, intentions to engage in non-native species management behaviors appear to be influenced by prior exposure to, and experience with, that species. Understanding the predictors of behavioral intentions at different stages of invasion have implications for the design of information strategies that can promote participation in control activities.

The human and social dimensions of invasion science and management

Biological invasions are a leading cause of global environmental change given their effects on both humans and biodiversity. Humans introduce invasive alien species and may facilitate their establishment and spread, which can alter ecosystem services, livelihoods, and human well-being. People perceive the benefits and costs of these species through the lens of diverse value systems; these perspectives influence decisions about when and where to manage them. Despite the entanglement of humans with invasive alien species, most research on the topic has focused on their ecological aspects. Only relatively recently have the human and social dimensions of invasions started to receive sustained attention in light of their importance for understanding and governing biological invasions. This editorial draws on contributions to a special issue on the "Human and Social Dimensions of Invasion Science" and other literature to elucidate major trends and current contributions in this research area. We examine the relation between humans and biological invasions in terms of four crosscutting themes: (1) how people cause biological invasions; (2) how people conceptualise and perceive them; (3) how people are affected - both positively and negatively - by them; and (4) how people respond to them. We also highlight several ways in which research on the human and social dimensions of invasion science improves understanding, stakeholder engagement, and management.

Landscape perceptions and social representations of Fallopia spp. in France

Choices have to be made to manage invasive species because eradication often is not possible. Both ecological and social factors have to be considered to improve the efficiency of management plans. We conducted a social study on Fallopia spp., a major invasive plant taxon in Europe, including (1) a survey on the perception of a landscape containing Fallopia spp. using a photoquestionnaire and (2) an analysis of the social representations of Fallopia spp. of managers and users in one highly invaded area and one less invaded area. The respondents to the photoquestionnaire survey appreciated the esthetics of the landscapes less when tall Fallopia spp. were present. Few people were able to identify and name the plant, and this knowledge negatively affected the appreciation of the photos containing Fallopia spp. The central core of the social representation of Fallopia spp. was composed of the invasive status of the plant, its density, and its ecological impacts. The peripheral elements of the representation depended on the people surveyed. The users highlighted the natural aspect whereas the managers identified the need for control. In the invaded area, the managers qualified the species as "unmanageable," whereas the species was qualified as "foreign" in the less invaded area. Those results provide insights that have to be included when objectives of management plans of these species are selected.